The document describes experiments conducted to measure pressure-concentration isotherms (PCI) for two mischmetal-based hydrogen storage alloys (MmNi3.9Co0.6Al0.5 and MmNi4Al) using both static and dynamic methods. The effects of hydrogen flow rate on plateau pressure, enthalpy of formation, and entropy of formation were studied. For MmNi3.9Co0.6Al0.5, both the shape of the PCI curve and plateau pressure depended on the flow rate, but flow rate did not significantly affect plateau pressure for MmNi4Al. Both alloys showed variations in enthalpy of formation with flow rate due to reaction rate changes
In order to study the WGS on an industrial scale at a low pressure, the modeling andsimulation of a WGS reactor operating at a pressure close to Patm and processing an industrial charge in the presence of a high temperature shift catalyst (Fe2O3/Cr2O3) were performed. The Profiles of the carbon monoxide conversion, temperature and pressure along the reactor were obtained. The effect of several operating parameters (inlet temperature, H2O/CO ratio) on the conversion of carbon monoxide along the reactor has been determined. The estimated catalytic mass to convert 60.5% of the carbon monoxide contained in the inlet is 170.76 t. The pressure drops in the reactor are not negligible and the maximum temperaturereached is without any harmful effect on the catalyst. The choice of an optimal inlet temperature and a high H2O/CO ratio improves the conversion of carbon monoxide.
This document summarizes a study on the thermal performance of a shell and tube heat exchanger using nanofluids. Finite volume modeling was used to analyze heat transfer and flow characteristics. Various nanofluids including Ag, Al2O3, CuO, SiO2, and TiO2 suspensions in water were tested and compared to pure water. The objectives were to analyze temperature profiles, heat transfer coefficients, pressure drops, and effectiveness. Results showed nanofluids had higher overall temperatures indicating more heat transfer compared to water alone. This study analyzed the potential for nanofluids to enhance heat exchanger performance.
Modelling and Simulation of Shell and Tube Heat Exchanger Using different Typ...IJMREMJournal
The shell and tube type of heat exchanger module is to be used for simulation study of various fluid systems on rate of heat transfer. The ionic fluids are used to see the difference in outlet temperature of fluid as compared to reference fluid. The cooling fluid is made by adding various amounts of solutes to water and the effect is observed on rate. Also suggestions are made on the nature of heat transfer, rate of heat transfer and improved effectiveness in the rate of heat transfer as compared to the normal process. The conclusions are made about the best simulated results obtain from Chemcad software on rate of heat transfer.
A Review on Study of Heat Transfer Analysis of Helical Coil Heat Exchangersijtsrd
Now a day’s a geometrically modified Helical coil heat exchangers are widely using in industrial applications like cryogenic state processes, air conditioning, thermal nuclear reactors and waste heat recovery due to their compact size and high heat transfer coefficient. Advantage of using helical coils over straight tubes is that the residence time spread is reduced, allowing helical coils to be used to reduce axial dispersion in tubular reactors. In this study, numerical investigation of the influence of geometrical parameters such as tube diameter d , coil radius R , and coil pitch p on overall heat transfer coefficient in helical double tube heat exchangers are performed using a professional CFD software FLUENT. In recent years, numerous styles were introduced for heat exchangers that apply to completely different applications sadly, their heat transfer co efficient wasnt reliable at different operational conditions. the standard of the heat changed rate wasnt optimized and there have been many deficiencies and errors in styles. The heat transfer of the copper material is enhanced in comparison with other material unfortunately thermal resistance is reduced with an increase in pressure drop thus enhancing the heat transfer on the heat exchanger. Helical architecture is often designed with a clear motive of compact size and also address heat transfer co efficient and other ancillary attributes efficiently and effectively. So the better material is suggested for an industrial heat exchanger according to the applications is Copper with the basis of simulation results. The geometry and different dimension parameter of the helical coil show that the proposed study in different material properties and different mass flow rates to heat transfer are maximum in different parameter helical coil heat exchangers. Finally, the heat transfer increase for the copper material compared to another material but with the increase in pressure drop the corresponding thermal resistance decreases which allow the improved heat transfer rate and the rate increases from Aluminum to Bronze to Copper. With the drop in temperature, the thermal resistance is reduced which enhances the heat transfer rate. The simulation results show that the copper has a high heat transfer coefficient than Aluminum and Bronze while operating in identical conditions. Due to the extensive use of helical coils in various applications, knowledge about the flow patterns and heat transfer characteristics are important. Atul Vats | Sunil Kumar Chaturvedi | Abhishek Bhandari "A Review on Study of Heat Transfer Analysis of Helical Coil Heat Exchangers" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd43650.pdf Paper URL: https://www.ijtsrd.comengineering/mechanical-engineering/43650/a-review-on-study-of-heat-transfer-analysis-of-helical-coil-heat-exchangers/atul-vats
Abstract:This paper deals with the thermal and CFD analysis of automobile radiator. The theoretical calculation has been done in MAT Lab by varying the mass flow rate of coolant. Modeling has been done in Solidworks and exported to Ansys for CFD analysis. The temperature distribution, heat transfer rate for different velocities of coolant to has been done for different tube materials such as copper, aluminium and stainless steel. The numerical results were compared and found that copper has best heat transfer rate and has better efficiency than the others.
Analytical Solution of Compartment Based Double Pipe Heat Exchanger using Di...IRJET Journal
This document discusses analytical solutions for a compartment-based double pipe heat exchanger model using the differential transform method. The model considers transformer oil as the hot fluid and water as the coolant fluid flowing in parallel through two compartments of the heat exchanger. Analytical expressions for the temperature profiles of the hot and cold fluids over time are derived. The solutions are shown to converge with increasing terms in the series solutions.
Fatigue Analysis of Acetylene converter reactorIJMER
The structural integrity of mechanical components during several transients should be
assured in the design stage. This requires a fatigue analysis including thermal and structural analysis. As
an example, this study performs a fatigue analysis of the acetylene converter reactor during arbitrary
transients. Using heat transfer coefficients determined based on the operating environments, a transient
thermal analysis is performed and the results are applied to a finite element model along with the
pressure to calculate the stresses. The total stress intensity range and cumulative fatigue usage factor are
investigated to determine the adequacy of the design
FlowVision CFD - Verification Calculations as per CFD FlowVision Code for Sod...capvidia
Application of FlowVision CFD Software for Analytical Validation of Sodium-Cooled Fast Reactor Structure Components
Verification of LMS (Liquid Metals Sodium) Turbulent Heat Transfer Model
Streaming and Mixing of Coolant Flows within "OKBM Afrikantov, BN-600 Reactor with Integral Layout of Equipment
In order to study the WGS on an industrial scale at a low pressure, the modeling andsimulation of a WGS reactor operating at a pressure close to Patm and processing an industrial charge in the presence of a high temperature shift catalyst (Fe2O3/Cr2O3) were performed. The Profiles of the carbon monoxide conversion, temperature and pressure along the reactor were obtained. The effect of several operating parameters (inlet temperature, H2O/CO ratio) on the conversion of carbon monoxide along the reactor has been determined. The estimated catalytic mass to convert 60.5% of the carbon monoxide contained in the inlet is 170.76 t. The pressure drops in the reactor are not negligible and the maximum temperaturereached is without any harmful effect on the catalyst. The choice of an optimal inlet temperature and a high H2O/CO ratio improves the conversion of carbon monoxide.
This document summarizes a study on the thermal performance of a shell and tube heat exchanger using nanofluids. Finite volume modeling was used to analyze heat transfer and flow characteristics. Various nanofluids including Ag, Al2O3, CuO, SiO2, and TiO2 suspensions in water were tested and compared to pure water. The objectives were to analyze temperature profiles, heat transfer coefficients, pressure drops, and effectiveness. Results showed nanofluids had higher overall temperatures indicating more heat transfer compared to water alone. This study analyzed the potential for nanofluids to enhance heat exchanger performance.
Modelling and Simulation of Shell and Tube Heat Exchanger Using different Typ...IJMREMJournal
The shell and tube type of heat exchanger module is to be used for simulation study of various fluid systems on rate of heat transfer. The ionic fluids are used to see the difference in outlet temperature of fluid as compared to reference fluid. The cooling fluid is made by adding various amounts of solutes to water and the effect is observed on rate. Also suggestions are made on the nature of heat transfer, rate of heat transfer and improved effectiveness in the rate of heat transfer as compared to the normal process. The conclusions are made about the best simulated results obtain from Chemcad software on rate of heat transfer.
A Review on Study of Heat Transfer Analysis of Helical Coil Heat Exchangersijtsrd
Now a day’s a geometrically modified Helical coil heat exchangers are widely using in industrial applications like cryogenic state processes, air conditioning, thermal nuclear reactors and waste heat recovery due to their compact size and high heat transfer coefficient. Advantage of using helical coils over straight tubes is that the residence time spread is reduced, allowing helical coils to be used to reduce axial dispersion in tubular reactors. In this study, numerical investigation of the influence of geometrical parameters such as tube diameter d , coil radius R , and coil pitch p on overall heat transfer coefficient in helical double tube heat exchangers are performed using a professional CFD software FLUENT. In recent years, numerous styles were introduced for heat exchangers that apply to completely different applications sadly, their heat transfer co efficient wasnt reliable at different operational conditions. the standard of the heat changed rate wasnt optimized and there have been many deficiencies and errors in styles. The heat transfer of the copper material is enhanced in comparison with other material unfortunately thermal resistance is reduced with an increase in pressure drop thus enhancing the heat transfer on the heat exchanger. Helical architecture is often designed with a clear motive of compact size and also address heat transfer co efficient and other ancillary attributes efficiently and effectively. So the better material is suggested for an industrial heat exchanger according to the applications is Copper with the basis of simulation results. The geometry and different dimension parameter of the helical coil show that the proposed study in different material properties and different mass flow rates to heat transfer are maximum in different parameter helical coil heat exchangers. Finally, the heat transfer increase for the copper material compared to another material but with the increase in pressure drop the corresponding thermal resistance decreases which allow the improved heat transfer rate and the rate increases from Aluminum to Bronze to Copper. With the drop in temperature, the thermal resistance is reduced which enhances the heat transfer rate. The simulation results show that the copper has a high heat transfer coefficient than Aluminum and Bronze while operating in identical conditions. Due to the extensive use of helical coils in various applications, knowledge about the flow patterns and heat transfer characteristics are important. Atul Vats | Sunil Kumar Chaturvedi | Abhishek Bhandari "A Review on Study of Heat Transfer Analysis of Helical Coil Heat Exchangers" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-4 , June 2021, URL: https://www.ijtsrd.compapers/ijtsrd43650.pdf Paper URL: https://www.ijtsrd.comengineering/mechanical-engineering/43650/a-review-on-study-of-heat-transfer-analysis-of-helical-coil-heat-exchangers/atul-vats
Abstract:This paper deals with the thermal and CFD analysis of automobile radiator. The theoretical calculation has been done in MAT Lab by varying the mass flow rate of coolant. Modeling has been done in Solidworks and exported to Ansys for CFD analysis. The temperature distribution, heat transfer rate for different velocities of coolant to has been done for different tube materials such as copper, aluminium and stainless steel. The numerical results were compared and found that copper has best heat transfer rate and has better efficiency than the others.
Analytical Solution of Compartment Based Double Pipe Heat Exchanger using Di...IRJET Journal
This document discusses analytical solutions for a compartment-based double pipe heat exchanger model using the differential transform method. The model considers transformer oil as the hot fluid and water as the coolant fluid flowing in parallel through two compartments of the heat exchanger. Analytical expressions for the temperature profiles of the hot and cold fluids over time are derived. The solutions are shown to converge with increasing terms in the series solutions.
Fatigue Analysis of Acetylene converter reactorIJMER
The structural integrity of mechanical components during several transients should be
assured in the design stage. This requires a fatigue analysis including thermal and structural analysis. As
an example, this study performs a fatigue analysis of the acetylene converter reactor during arbitrary
transients. Using heat transfer coefficients determined based on the operating environments, a transient
thermal analysis is performed and the results are applied to a finite element model along with the
pressure to calculate the stresses. The total stress intensity range and cumulative fatigue usage factor are
investigated to determine the adequacy of the design
FlowVision CFD - Verification Calculations as per CFD FlowVision Code for Sod...capvidia
Application of FlowVision CFD Software for Analytical Validation of Sodium-Cooled Fast Reactor Structure Components
Verification of LMS (Liquid Metals Sodium) Turbulent Heat Transfer Model
Streaming and Mixing of Coolant Flows within "OKBM Afrikantov, BN-600 Reactor with Integral Layout of Equipment
The document describes the monitoring instrumentation used for a helium liquefier system at the University of North Florida Physics Department. It discusses a hygrometer and purity meter that detect impurities like water moisture in stored helium gas and indicate when maintenance is needed. It also describes setting up and collaborating on a LabVIEW program to ensure proper operation of these instruments for efficient liquefaction of helium gas.
Performance prediction of a thermal system using Artificial Neural NetworksIJERD Editor
This document summarizes a study on using artificial neural networks (ANNs) to predict the performance of a condenser system and assess fouling over time. Experiments were conducted on an industrial condenser to collect temperature and flow rate data. An ANN model was developed and trained to predict the overall heat transfer coefficient of the clean condenser system based on the input parameters. The model was then used to calculate the fouling factor by comparing the predicted clean performance to the actual performance measured over time, indicating degradation due to fouling on the heat transfer surfaces. The developed system provides a method to monitor condenser performance and identify when cleaning is needed to improve efficiency.
CFD Simulation and Heat Transfer Analysis of Automobile Radiator using Helica...IJERD Editor
To ensure smooth running of an automotive vehicle under any variable load conditions, one of the major systems necessary is the cooling system. Automobile radiators are becoming highly power-packed with increasing power to weight or volume ratio. Computational Fluid Dynamics (CFD) is one of the important software tools to access preliminary design and the performance of the radiator. In this paper, a 55 hp engine radiator data is taken for analysis in CFD. The model is done Pro-E software and imported in ANSYS-12. Helical tubes are considered for the radiator with two different pitches like 15mm & 20mm. The comparison is done for different mass flow rates like 2.3, 2.0, 1.0, 0.5 kg/sec in helical type tubes. It is found that there is more heat dissipation rate in 15mm pitch helical tubes compared to 20mm pitch helical tubes. Maximum temperature drop & minimum pressure drop occurs in case of 0.5 kg/sec of mass flow rate. It is observed that with increased mass flow rate, there is decrease in temperature drop & increase in pressure drop
IRJET- Experimental Investigation of Pipe in Pipe Tube Heat Exchanger using S...IRJET Journal
This document presents an experimental investigation of a pipe-in-pipe tube heat exchanger using silica (SiO2) nanofluid. The heat exchanger consists of an outer steel pipe and inner aluminum pipe. SiO2 nanofluid with 2% volume concentration and 100nm nanoparticle size is used and compared to water as the base fluid. Test results show that the nanofluid improves heat transfer characteristics and heat transfer coefficient compared to water. Specifically, the effectiveness of the heat exchanger increased by 23.1% when using nanofluid versus water. Varying the mass flow rate was also found to impact the heat transfer rate and effectiveness.
IRJET- Thermal and Fluid Flow Analysis of a Heat Exchanger: “A Comprehensive ...IRJET Journal
This document provides a comprehensive literature review and analysis of thermal and fluid flow performance in heat exchangers. It discusses several types of heat exchangers and techniques used to enhance heat transfer, such as surface textures, channel designs, and nanofluids. The document reviews experimental, numerical, and computational studies on fluid flow characteristics and heat transfer for different heat exchanger configurations and applications. It also provides governing equations for fluid flow and heat transfer analysis and compares experimental results to analytical predictions using correlations.
PREDICTIONS AT THE BLOW END OF THE LD-KGC CONVERTER BY A SEMI-DYNAMIC CONTROL...ijmech
The decision to perform direct turn-down or not, based on an accurate estimate of temperature at the blow end, prevents two types of problems: (a) the loss of productivity due to the wait time in the steelmaking; and (b) tapping of off-specification heat.
In the present work, a technique and model for temperature prediction at the blow end are briefly discussed, along with their limitations and perspectives for application. As a result of this analysis, a mathematical model based in heat and mass balances has been developed with a view to evaluating the possibility of improving this prediction capability. The formulation of said model and its preliminary adjustment to industrial data are presented and discussed, and the main limitations and difficulties in the application of the methodology are highlighted.
The study here presented focuses the development of a semi-dynamic control model in the LD-KGC converter (Linz-Donawitz-Kawasaki Gas Control Converter). The control model enables one to predict the temperature of the blow end by solving both the energy and mass equations. The computational language adopted is Fortran 90; the equations are solved iteratively until a solution for temperature is found. The inputs to the control model are the load data of the LD-KGC converter at the blow beginning and the collected data by the lance to 89% of oxygen blow. The results obtained in the present work were compared to the data measured in steel making. The semi-dynamic control model results agree well with data for LDKGC converters. However, the model is sensitive to the premises here adopted, like those pertaining to the exit gas composition (CO and CO2).
This document summarizes a sensitivity analysis of parameters affecting the temperature and life of a high-pressure, high-temperature turbine blade. It finds that increasing the thermal barrier coating thickness by 3 times leads to a 9-fold increase in blade life. Coolant inlet temperature and pressure also significantly impact blade temperature, with temperature deviations having a greater effect on life. The analysis further determines that 300 hours of operation at 70% load is equivalent to 1 hour at full load in terms of blade life.
JIMEC Thermal modeling and Simulation of HX Conference PaperAhmed Sohail Izhar
1) The document describes a thermal modeling and simulation of an industrial shell and tube heat exchanger used to cool raw natural gas.
2) A thermal model was developed using the effectiveness-NTU method to determine the required heat transfer area and estimate the tube-side and shell-side heat transfer coefficients.
3) The results of the model showed that a heat transfer area of about 1132 m2 is required to provide a thermal duty of 1.4 MW, with tube-side and shell-side heat transfer coefficients of 950 W/m2K and 495 W/m2K respectively.
Computational Fluid Dynamic Analysis for Optimization of Helical Coil Heat Ex...IRJET Journal
This document analyzes computational fluid dynamic (CFD) optimization of a helical coil heat exchanger. It compares CFD analysis results to experimental results and finds that decreasing the pitch length of the helical coil and relative velocity of fluids increases heat transfer rate. The document also describes an experimental setup used to study a helical coil heat exchanger and discusses previous research analyzing factors that affect heat transfer in helical coil exchangers, such as pitch length, tube diameter, and fluid velocity.
A Review on Developments in Technologies of Heat Exchangers WorldwideIRJET Journal
This document reviews developments in heat exchanger technologies worldwide, specifically focusing on helical coil heat exchangers. It summarizes 13 research papers on helical coil heat exchangers, discussing how they enhance heat transfer rates compared to straight tube exchangers and examining factors like coil geometry, fluid properties, and temperature that affect heat transfer performance. The document concludes that while helical coil exchangers provide more efficient heat transfer, correlations to predict performance are impacted by parameters like coil diameter, pitch, and inlet fluid properties and conditions.
IRJET- Heat Transfer Studies of Corrugated Plate Heat Exchanger using OilIRJET Journal
This document presents a study on heat transfer in corrugated plate heat exchangers using oil as the heat transfer fluid. Three corrugated plate heat exchangers with angles of 30°, 40°, and 50° were experimentally tested and compared to a flat plate heat exchanger. The heat transfer coefficient and Nusselt number increased with increasing Reynolds number and corrugation angle. The 50° corrugation angle achieved the highest heat transfer rates, representing a 40% increase over the 30° angle. Using oil as the fluid resulted in slightly higher heat transfer compared to previous studies using water. The experimental results agreed with previous CFD analyses showing improved performance of corrugated plates over flat plates.
Heat exchangers are used widely in industrial application such as chemical,
food processing, power production, refrigeration and air-conditioning
industries. Helical coiled heat exchangers are used in order to obtain a large
heat transfer per unit volume and to enhance the heat transfer rate on the inside
surface. In the present study, CFD simulations are carried out for a counter
flow tube in tube helical heat exchanger where hot water flows through the
inner tube and cold water flows through the outer tube. From the simulation
results heat transfer coefficient, pressure drop and nusselt number are
calculated. The heat transfer characteristics of the same are compared with that
of a counter flow tube in tube straight tube heat exchanger of same length
under same temperature and flow conditions. CFD simulation results showed
that the helical tube in tube heat exchanger is more effective than the straight
tube in tube heat exchanger.
Comparative Study of ECONOMISER Using the CFD Analysis IJMER
This paper presents a simulation of the economizer zone, which allowsstudying the flow
patterns developed in the fluid, while it flows along the length of the economizer. The past failure
details revelsthat erosion is more in U-bend areas of Economizer Unit because of increase in flue gas
velocity near these bends. But it isobserved that the velocity of flue gases surprisingly increases near
the lower bends as compared to upper ones. The model issolved using conventional CFD techniques by
FLUENT software. In which the individual tubes are treated as sub-gridfeatures. A geometrical model
is used to describe the multiplicity of heat-exchanging structures and the interconnectionsamong them.
The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional
modelof the economizer coil of single column tube. With equilibrium assumption applied for
description of the system chemistry. The flue gastemperature, pressure and velocity field of fluid flow
within an economizer tube using the actual bounda
Numerical Analysis of Heat Transfer Enhancement in Pipe-inPipe Helical Coiled...iosrjce
This document presents a numerical analysis of heat transfer enhancement in pipe-in-pipe helical coiled heat exchangers. Computational fluid dynamics (CFD) was used to analyze the effect of varying parameters like inner tube diameter, mass flow rates, and flow configuration (parallel vs. counter flow). The results show that overall heat transfer coefficients increase with increasing inner Dean number and mass flow rates. Heat transfer rates also increase with higher inner mass flow rates. Counter flow configuration provides better heat transfer than parallel flow. Increasing the inner tube size decreases the total heat transfer rate due to a reduction in annulus cross-sectional area. Measured inner Nusselt numbers agree reasonably well with existing correlations.
Experimental investigate to obtain the effectiveness of regenerator using Air.IJESFT
The regenerator is a kind of heat exchanger that provides a way to get the gas to the low temperature with as much potential work (cooling power) as possible without carrying a lot of heat with it. It doesn’t put heat in or out of the system but it absorbs heat from the gas on one part of the pressure cycle and returns heat to the gas on the other part.
More recent applications of regenerators in cryogenic systems can be found in small cryogenic refrigerators (cryocoolers). Systems such as the Stirling Gifford-McMahon, pulse tube, Solvay, Vuilleumier and magnetic cycle refrigerators all use either a static or rotary regenerator. In fact, the success these coolers have achieved is directly related to the characteristics of compact size and efficiency of the regenerator.
Regenerator effectiveness of 99% results in 21% loss of refrigeration effect, similarly regenerator effectiveness of 98% results in 42% loss of refrigeration effect, with refrigeration effectiveness of 95.238% the loss of refrigeration is 100%. i.e. no net cooling is produced.
In cryogenic applications the regenerator is typically made up of 100 to 500 meshes SS 304, Phosphorous bronze screens or small lead spheres (150 to 300 micro meters) are used, that are tightly packed together and held in place on either end in the same manner.
To develop experimental setup at our laboratory level by using air as working fluid and find out the effectiveness of various regenerative materials is basic goal of this work.
CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin InclinationsIJERA Editor
ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT was used in the fin-tube heat exchanger. The fluid flow and heat transfer are simulated and result compared for both laminar and turbulent flow models k-epsilon and SST k-omega, with steady state solvers to calculate heat transfer, flow velocity and temperature fields of variable inclined fin angles (Ɵ = 00,100 , 200, 300, 400,500). Model is validate by comparing the simulated value of velocity, temperature and colburn factor with experimental and numerical results investigated by WANG [1] and GHORI KIRAR [10]. Reasonable agreement is found between the simulations and other results, and the ANSYS Fluent software is sufficient for simulating the flow fields in tube fin heat exchanger.
This document discusses air transient cooling characteristics in the entry regions of ducts with non-circular cross sections. It presents correlations and equations to calculate the hydrodynamic and thermal entrance lengths for triangular, rectangular, circular and square ducts. It also provides equations for the local Nusselt number and convective heat transfer coefficient in the combined entry region where the flow is both thermally and hydrodynamically developing. The analysis considers the transient heat transfer in the duct entry regions using temperature-dependent air properties and numerical modeling. The results indicate that the triangular duct enhances heat transfer the most compared to the other cross section ducts.
With increasing pollution worldwide, the emission standards for diesel engines has become more stringent. The Euro 6 limits the NOxemission from diesel engine to 0.08 g Km. The current paper presents the various analysis method of EGR cooler operating under different conditions. The primary causes of EGR failures i.e. fouling is also studied by various scholars. The numerical method CFD encompassing 1D geometry and experimental techniques of evaluating EGR cooler is also studied. The effect of geometry, material and operating conditions on performance of EGR cooler are investigated by various scholars and the results obtained by such tests are also presented. Dwarika Sahu | Dr. S. S. K. Deepak "Review on Numerical Analysis of EGR Cooler" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33570.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/33570/review-on-numerical-analysis-of-egr-cooler/dwarika-sahu
Effect of nanofluid on friction factor of pipe and pipe fittings part ii ef...eSAT Journals
Abstract A nanofluid is prepared by mixing nano sized particles of size up to 100 nm and a base fluid. Commonly used nanoparticles are made of metals, oxides or carbides, while base fluids may be water, ethylene glycol or oil. Normally, the application of nanofluids is to enhance the heat transfer rate. Due to mixing of nanoparticles in the base fluid, the thermo-physical properties of the resulting mixture (base fluid + nanoparticles) changes. Therefore, resistance to flow of nanofluid increases which increases the friction factor and reduces the flow rate. In the part I of paper, an experimental investigation has been carried out to determine the effect of various concentration of Al2O3 nano-dispersion mixed in water as base fluid on Friction Factor of Pipe and Pipe Fittings. The present study deals with the effect of CuO nanofluid on the Friction Factor of Pipe and Pipe Fittings. The friction factor and loss coefficient of different pipes and pipe fittings increase with increase in volume concentration of CuO in water as compared to water. Keywords: Nanofluid, Friction Factor, Pipe Friction, Pipe Fitting, CuO Nanoparticles
this is the representation of hydrogen fuel. In this presentation we showed how hydrogen is useful for future consumption of fuel. We know that in the future the non-renewable sources of energy will be extincted so we have to concentrate on conventional sources of energy like solar energy energy, nuclear energy, hydrogen fuel. Because hydrogen is highly combustible and produce large of energy so we consider to use hydrogen fuel in future aspect
This certificate from the International Journal of Hydrogen Energy certifies the publication of an article titled "Environmental impact assessment and comparison of some hydrogen production options" authored by Fahad Suleman and Ibrahim Dincer. The article was published in Volume 40, Issue 21 of the journal in 2015, spanning pages 6976-6987.
Hydrogen And Fuel Cell Technology For A Sustainable FutureGavin Harper
The document discusses renewable energy sources like hydrogen produced from electrolysis of water using wind turbine power on the Scottish island of Unst. It describes how the hydrogen is then used in fuel cells to provide electricity, heat, and power for homes and vehicles on the island in a self-sufficient system without connections to the national grid. Examples are given of other projects using hydrogen and fuel cells from homes to larger buildings to demonstrate renewable energy integration and zero carbon energy systems.
The document describes the monitoring instrumentation used for a helium liquefier system at the University of North Florida Physics Department. It discusses a hygrometer and purity meter that detect impurities like water moisture in stored helium gas and indicate when maintenance is needed. It also describes setting up and collaborating on a LabVIEW program to ensure proper operation of these instruments for efficient liquefaction of helium gas.
Performance prediction of a thermal system using Artificial Neural NetworksIJERD Editor
This document summarizes a study on using artificial neural networks (ANNs) to predict the performance of a condenser system and assess fouling over time. Experiments were conducted on an industrial condenser to collect temperature and flow rate data. An ANN model was developed and trained to predict the overall heat transfer coefficient of the clean condenser system based on the input parameters. The model was then used to calculate the fouling factor by comparing the predicted clean performance to the actual performance measured over time, indicating degradation due to fouling on the heat transfer surfaces. The developed system provides a method to monitor condenser performance and identify when cleaning is needed to improve efficiency.
CFD Simulation and Heat Transfer Analysis of Automobile Radiator using Helica...IJERD Editor
To ensure smooth running of an automotive vehicle under any variable load conditions, one of the major systems necessary is the cooling system. Automobile radiators are becoming highly power-packed with increasing power to weight or volume ratio. Computational Fluid Dynamics (CFD) is one of the important software tools to access preliminary design and the performance of the radiator. In this paper, a 55 hp engine radiator data is taken for analysis in CFD. The model is done Pro-E software and imported in ANSYS-12. Helical tubes are considered for the radiator with two different pitches like 15mm & 20mm. The comparison is done for different mass flow rates like 2.3, 2.0, 1.0, 0.5 kg/sec in helical type tubes. It is found that there is more heat dissipation rate in 15mm pitch helical tubes compared to 20mm pitch helical tubes. Maximum temperature drop & minimum pressure drop occurs in case of 0.5 kg/sec of mass flow rate. It is observed that with increased mass flow rate, there is decrease in temperature drop & increase in pressure drop
IRJET- Experimental Investigation of Pipe in Pipe Tube Heat Exchanger using S...IRJET Journal
This document presents an experimental investigation of a pipe-in-pipe tube heat exchanger using silica (SiO2) nanofluid. The heat exchanger consists of an outer steel pipe and inner aluminum pipe. SiO2 nanofluid with 2% volume concentration and 100nm nanoparticle size is used and compared to water as the base fluid. Test results show that the nanofluid improves heat transfer characteristics and heat transfer coefficient compared to water. Specifically, the effectiveness of the heat exchanger increased by 23.1% when using nanofluid versus water. Varying the mass flow rate was also found to impact the heat transfer rate and effectiveness.
IRJET- Thermal and Fluid Flow Analysis of a Heat Exchanger: “A Comprehensive ...IRJET Journal
This document provides a comprehensive literature review and analysis of thermal and fluid flow performance in heat exchangers. It discusses several types of heat exchangers and techniques used to enhance heat transfer, such as surface textures, channel designs, and nanofluids. The document reviews experimental, numerical, and computational studies on fluid flow characteristics and heat transfer for different heat exchanger configurations and applications. It also provides governing equations for fluid flow and heat transfer analysis and compares experimental results to analytical predictions using correlations.
PREDICTIONS AT THE BLOW END OF THE LD-KGC CONVERTER BY A SEMI-DYNAMIC CONTROL...ijmech
The decision to perform direct turn-down or not, based on an accurate estimate of temperature at the blow end, prevents two types of problems: (a) the loss of productivity due to the wait time in the steelmaking; and (b) tapping of off-specification heat.
In the present work, a technique and model for temperature prediction at the blow end are briefly discussed, along with their limitations and perspectives for application. As a result of this analysis, a mathematical model based in heat and mass balances has been developed with a view to evaluating the possibility of improving this prediction capability. The formulation of said model and its preliminary adjustment to industrial data are presented and discussed, and the main limitations and difficulties in the application of the methodology are highlighted.
The study here presented focuses the development of a semi-dynamic control model in the LD-KGC converter (Linz-Donawitz-Kawasaki Gas Control Converter). The control model enables one to predict the temperature of the blow end by solving both the energy and mass equations. The computational language adopted is Fortran 90; the equations are solved iteratively until a solution for temperature is found. The inputs to the control model are the load data of the LD-KGC converter at the blow beginning and the collected data by the lance to 89% of oxygen blow. The results obtained in the present work were compared to the data measured in steel making. The semi-dynamic control model results agree well with data for LDKGC converters. However, the model is sensitive to the premises here adopted, like those pertaining to the exit gas composition (CO and CO2).
This document summarizes a sensitivity analysis of parameters affecting the temperature and life of a high-pressure, high-temperature turbine blade. It finds that increasing the thermal barrier coating thickness by 3 times leads to a 9-fold increase in blade life. Coolant inlet temperature and pressure also significantly impact blade temperature, with temperature deviations having a greater effect on life. The analysis further determines that 300 hours of operation at 70% load is equivalent to 1 hour at full load in terms of blade life.
JIMEC Thermal modeling and Simulation of HX Conference PaperAhmed Sohail Izhar
1) The document describes a thermal modeling and simulation of an industrial shell and tube heat exchanger used to cool raw natural gas.
2) A thermal model was developed using the effectiveness-NTU method to determine the required heat transfer area and estimate the tube-side and shell-side heat transfer coefficients.
3) The results of the model showed that a heat transfer area of about 1132 m2 is required to provide a thermal duty of 1.4 MW, with tube-side and shell-side heat transfer coefficients of 950 W/m2K and 495 W/m2K respectively.
Computational Fluid Dynamic Analysis for Optimization of Helical Coil Heat Ex...IRJET Journal
This document analyzes computational fluid dynamic (CFD) optimization of a helical coil heat exchanger. It compares CFD analysis results to experimental results and finds that decreasing the pitch length of the helical coil and relative velocity of fluids increases heat transfer rate. The document also describes an experimental setup used to study a helical coil heat exchanger and discusses previous research analyzing factors that affect heat transfer in helical coil exchangers, such as pitch length, tube diameter, and fluid velocity.
A Review on Developments in Technologies of Heat Exchangers WorldwideIRJET Journal
This document reviews developments in heat exchanger technologies worldwide, specifically focusing on helical coil heat exchangers. It summarizes 13 research papers on helical coil heat exchangers, discussing how they enhance heat transfer rates compared to straight tube exchangers and examining factors like coil geometry, fluid properties, and temperature that affect heat transfer performance. The document concludes that while helical coil exchangers provide more efficient heat transfer, correlations to predict performance are impacted by parameters like coil diameter, pitch, and inlet fluid properties and conditions.
IRJET- Heat Transfer Studies of Corrugated Plate Heat Exchanger using OilIRJET Journal
This document presents a study on heat transfer in corrugated plate heat exchangers using oil as the heat transfer fluid. Three corrugated plate heat exchangers with angles of 30°, 40°, and 50° were experimentally tested and compared to a flat plate heat exchanger. The heat transfer coefficient and Nusselt number increased with increasing Reynolds number and corrugation angle. The 50° corrugation angle achieved the highest heat transfer rates, representing a 40% increase over the 30° angle. Using oil as the fluid resulted in slightly higher heat transfer compared to previous studies using water. The experimental results agreed with previous CFD analyses showing improved performance of corrugated plates over flat plates.
Heat exchangers are used widely in industrial application such as chemical,
food processing, power production, refrigeration and air-conditioning
industries. Helical coiled heat exchangers are used in order to obtain a large
heat transfer per unit volume and to enhance the heat transfer rate on the inside
surface. In the present study, CFD simulations are carried out for a counter
flow tube in tube helical heat exchanger where hot water flows through the
inner tube and cold water flows through the outer tube. From the simulation
results heat transfer coefficient, pressure drop and nusselt number are
calculated. The heat transfer characteristics of the same are compared with that
of a counter flow tube in tube straight tube heat exchanger of same length
under same temperature and flow conditions. CFD simulation results showed
that the helical tube in tube heat exchanger is more effective than the straight
tube in tube heat exchanger.
Comparative Study of ECONOMISER Using the CFD Analysis IJMER
This paper presents a simulation of the economizer zone, which allowsstudying the flow
patterns developed in the fluid, while it flows along the length of the economizer. The past failure
details revelsthat erosion is more in U-bend areas of Economizer Unit because of increase in flue gas
velocity near these bends. But it isobserved that the velocity of flue gases surprisingly increases near
the lower bends as compared to upper ones. The model issolved using conventional CFD techniques by
FLUENT software. In which the individual tubes are treated as sub-gridfeatures. A geometrical model
is used to describe the multiplicity of heat-exchanging structures and the interconnectionsamong them.
The Computational Fluid Dynamics (CFD) approach is utilised for the creation of a three-dimensional
modelof the economizer coil of single column tube. With equilibrium assumption applied for
description of the system chemistry. The flue gastemperature, pressure and velocity field of fluid flow
within an economizer tube using the actual bounda
Numerical Analysis of Heat Transfer Enhancement in Pipe-inPipe Helical Coiled...iosrjce
This document presents a numerical analysis of heat transfer enhancement in pipe-in-pipe helical coiled heat exchangers. Computational fluid dynamics (CFD) was used to analyze the effect of varying parameters like inner tube diameter, mass flow rates, and flow configuration (parallel vs. counter flow). The results show that overall heat transfer coefficients increase with increasing inner Dean number and mass flow rates. Heat transfer rates also increase with higher inner mass flow rates. Counter flow configuration provides better heat transfer than parallel flow. Increasing the inner tube size decreases the total heat transfer rate due to a reduction in annulus cross-sectional area. Measured inner Nusselt numbers agree reasonably well with existing correlations.
Experimental investigate to obtain the effectiveness of regenerator using Air.IJESFT
The regenerator is a kind of heat exchanger that provides a way to get the gas to the low temperature with as much potential work (cooling power) as possible without carrying a lot of heat with it. It doesn’t put heat in or out of the system but it absorbs heat from the gas on one part of the pressure cycle and returns heat to the gas on the other part.
More recent applications of regenerators in cryogenic systems can be found in small cryogenic refrigerators (cryocoolers). Systems such as the Stirling Gifford-McMahon, pulse tube, Solvay, Vuilleumier and magnetic cycle refrigerators all use either a static or rotary regenerator. In fact, the success these coolers have achieved is directly related to the characteristics of compact size and efficiency of the regenerator.
Regenerator effectiveness of 99% results in 21% loss of refrigeration effect, similarly regenerator effectiveness of 98% results in 42% loss of refrigeration effect, with refrigeration effectiveness of 95.238% the loss of refrigeration is 100%. i.e. no net cooling is produced.
In cryogenic applications the regenerator is typically made up of 100 to 500 meshes SS 304, Phosphorous bronze screens or small lead spheres (150 to 300 micro meters) are used, that are tightly packed together and held in place on either end in the same manner.
To develop experimental setup at our laboratory level by using air as working fluid and find out the effectiveness of various regenerative materials is basic goal of this work.
CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin InclinationsIJERA Editor
ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT was used in the fin-tube heat exchanger. The fluid flow and heat transfer are simulated and result compared for both laminar and turbulent flow models k-epsilon and SST k-omega, with steady state solvers to calculate heat transfer, flow velocity and temperature fields of variable inclined fin angles (Ɵ = 00,100 , 200, 300, 400,500). Model is validate by comparing the simulated value of velocity, temperature and colburn factor with experimental and numerical results investigated by WANG [1] and GHORI KIRAR [10]. Reasonable agreement is found between the simulations and other results, and the ANSYS Fluent software is sufficient for simulating the flow fields in tube fin heat exchanger.
This document discusses air transient cooling characteristics in the entry regions of ducts with non-circular cross sections. It presents correlations and equations to calculate the hydrodynamic and thermal entrance lengths for triangular, rectangular, circular and square ducts. It also provides equations for the local Nusselt number and convective heat transfer coefficient in the combined entry region where the flow is both thermally and hydrodynamically developing. The analysis considers the transient heat transfer in the duct entry regions using temperature-dependent air properties and numerical modeling. The results indicate that the triangular duct enhances heat transfer the most compared to the other cross section ducts.
With increasing pollution worldwide, the emission standards for diesel engines has become more stringent. The Euro 6 limits the NOxemission from diesel engine to 0.08 g Km. The current paper presents the various analysis method of EGR cooler operating under different conditions. The primary causes of EGR failures i.e. fouling is also studied by various scholars. The numerical method CFD encompassing 1D geometry and experimental techniques of evaluating EGR cooler is also studied. The effect of geometry, material and operating conditions on performance of EGR cooler are investigated by various scholars and the results obtained by such tests are also presented. Dwarika Sahu | Dr. S. S. K. Deepak "Review on Numerical Analysis of EGR Cooler" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-6 , October 2020, URL: https://www.ijtsrd.com/papers/ijtsrd33570.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/33570/review-on-numerical-analysis-of-egr-cooler/dwarika-sahu
Effect of nanofluid on friction factor of pipe and pipe fittings part ii ef...eSAT Journals
Abstract A nanofluid is prepared by mixing nano sized particles of size up to 100 nm and a base fluid. Commonly used nanoparticles are made of metals, oxides or carbides, while base fluids may be water, ethylene glycol or oil. Normally, the application of nanofluids is to enhance the heat transfer rate. Due to mixing of nanoparticles in the base fluid, the thermo-physical properties of the resulting mixture (base fluid + nanoparticles) changes. Therefore, resistance to flow of nanofluid increases which increases the friction factor and reduces the flow rate. In the part I of paper, an experimental investigation has been carried out to determine the effect of various concentration of Al2O3 nano-dispersion mixed in water as base fluid on Friction Factor of Pipe and Pipe Fittings. The present study deals with the effect of CuO nanofluid on the Friction Factor of Pipe and Pipe Fittings. The friction factor and loss coefficient of different pipes and pipe fittings increase with increase in volume concentration of CuO in water as compared to water. Keywords: Nanofluid, Friction Factor, Pipe Friction, Pipe Fitting, CuO Nanoparticles
this is the representation of hydrogen fuel. In this presentation we showed how hydrogen is useful for future consumption of fuel. We know that in the future the non-renewable sources of energy will be extincted so we have to concentrate on conventional sources of energy like solar energy energy, nuclear energy, hydrogen fuel. Because hydrogen is highly combustible and produce large of energy so we consider to use hydrogen fuel in future aspect
This certificate from the International Journal of Hydrogen Energy certifies the publication of an article titled "Environmental impact assessment and comparison of some hydrogen production options" authored by Fahad Suleman and Ibrahim Dincer. The article was published in Volume 40, Issue 21 of the journal in 2015, spanning pages 6976-6987.
Hydrogen And Fuel Cell Technology For A Sustainable FutureGavin Harper
The document discusses renewable energy sources like hydrogen produced from electrolysis of water using wind turbine power on the Scottish island of Unst. It describes how the hydrogen is then used in fuel cells to provide electricity, heat, and power for homes and vehicles on the island in a self-sufficient system without connections to the national grid. Examples are given of other projects using hydrogen and fuel cells from homes to larger buildings to demonstrate renewable energy integration and zero carbon energy systems.
The document provides an overview of hydrogen fuel cells, including their history, types, basic functioning, and connections to electrochemistry, thermodynamics, the environment, and potential applications as an energy source. It discusses how hydrogen fuel cells work through redox reactions at the anode and cathode to produce electricity from hydrogen and oxygen, and are more efficient than combustion engines due to their electrochemical rather than combustion process. It also notes that hydrogen fuel cells can be powered through renewable energy sources like electrolysis of water using solar or hydro power.
This very short document appears to be in an unfamiliar language and does not provide much contextual information to summarize. It contains a few words that are unclear in meaning along with references to place names that are not well known out of context. The document leaves off with an ambiguous ending of "The end? To be continued".
Art is a creative expression that stimulates the senses or imagination according to Felicity Hampel. Picasso believed that every child is an artist but growing up can stop that creativity. Aristotle defined art as anything requiring a maker and not being able to create itself.
CFD Analysis and Melting Performance of PCMs in Two Dimensional SphereIRJET Journal
This document summarizes a numerical study comparing the melting performance of three phase change materials (PCMs) - paraffin wax, sodium acetate trihydrate, and lauric acid - in a two-dimensional hollow spherical container. The study uses computational fluid dynamics (CFD) simulations to analyze melt fraction contours and temperature distributions over time as each PCM melts. Grid independence and time independence tests were performed to select appropriate mesh and time step sizes for the simulations. Results show the energy stored by each PCM and compare their melting performances.
Experimental Study on Phase Change Material based Thermal Energy Storage SystemIRJET Journal
1) The document describes an experimental study on using phase change materials (PCMs) like calcium chloride hexahydrate and sodium carbonate decahydrate to store thermal energy.
2) The experiment involved charging two PCMs by flowing hot water through a copper tube containing the PCMs, and discharging by flowing cold water, measuring temperatures over time.
3) The results showed that increasing the flow rate of the heat transfer fluid during charging and discharging increased the heat storage and release capacity of both PCMs.
Analysis of Double Pipe Heat Exchanger With Helical FinsIRJET Journal
This document analyzes a double pipe heat exchanger with helical fins through computational fluid dynamics (CFD). It aims to study the flow and temperature fields inside the tubes for different helical fin angles. The geometry of the double pipe heat exchanger is modeled in CATIA V5 and meshed in Hypermesh. CFD simulations are performed in ANSYS Fluent to analyze the flow and temperature distributions for fin angles of 0, 5, 10, 15, 20, and 25 degrees. The results determine that heat transfer rate and overall heat transfer coefficient increase with helical fins compared to a smooth tube, with fins providing additional surface area to enhance heat transfer.
Comparison of Experimental and DELTA-EC Results on performance of Thermoacous...IRJET Journal
This document compares the experimental and theoretical (DELTA-EC model) results of a thermoacoustic refrigerator's performance under different operating conditions. The refrigerator was tested experimentally for heating loads ranging from 2-10 watts, drive ratios of 1.6-2%, and frequencies of 200-600 Hz. The experimental temperatures and theoretical DELTA-EC temperatures showed similar trends but the experimental results deviated by about 26% due to viscous effects, discontinuities, turbulence, and heat losses not accounted for in the model. The highest temperature difference was obtained experimentally at 2 watts, 400 Hz, and 2% drive ratio.
IRJET- Experimental Investigation of Radiator using Tio2 Nano Fluid as CoolantIRJET Journal
The document presents an experimental investigation into using titanium dioxide (TiO2) nanofluid as a coolant in a car radiator. An experimental setup is designed to test the performance of the radiator using water, ethylene glycol, and TiO2 nanofluid as coolants. Various parameters like temperature difference, average heat transfer rate, effectiveness, and pressure drop are measured and compared between the different coolants. The results show that the TiO2 nanofluid provides better cooling performance than water or ethylene glycol alone, with higher heat transfer rates and effectiveness. This is due to the enhanced thermal conductivity provided by the titanium dioxide nanoparticles suspended in the base fluid. In conclusion, nanofluids show potential for improving the efficiency of autom
IRJET-Performance Simulation of Hydrogen Sorption in Metal Hydride based stor...IRJET Journal
This document discusses the simulation of hydrogen sorption in metal hydride-based storage beds using the 2D Lattice Boltzmann method. Metal hydrides can reversibly store hydrogen through exothermic absorption and endothermic desorption reactions. Heat transfer limits the rate of these reactions in metal hydride beds. The document aims to study heat and mass transfer in metal hydride beds using the 2D Lattice Boltzmann method to analyze the effects of parameters like supply pressure, coolant temperature, and bed thickness on sorption performance. The results will be compared to experimental data.
SRNL Acceptability Envelope metal hydrideschrisrobschu
The design and evaluation of media-based hydrogen storage systems requires the use of
detailed numerical models and experimental studies, with significant amount of time and
monetary investment. Thus a scoping tool, referred to as the Acceptability Envelope, was
developed to screen preliminary candidate media and storage vessel designs, identifying
the range of chemical, physical and geometrical parameters for the coupled media and
storage vessel system that allow it to meet performance targets. The model which
underpins the analysis allows simplifying the storage system, thus resulting in one inputone
output scheme, by grouping of selected quantities.
Two cases have been analyzed and results are presented here. In the first application
the DOE technical targets (Year 2010, Year 2015 and Ultimate) are used to determine the
range of parameters required for the metal hydride media and storage vessel. In the second
case the most promising metal hydrides available are compared, highlighting the potential
of storage systems, utilizing them, to achieve 40% of the 2010 DOE technical target. Results
show that systems based on LiMg media have the best potential to attain these performance
targets.
Srnl acceptability
envelope_metal_hydride_h2_int_j_hydrogen_energy_2012_37
Manufacturing of Sodium Titanate from Egyptian Rutile Concentrate for Welding...IRJET Journal
This document summarizes research on manufacturing sodium titanate from Egyptian rutile concentrate for use as an additive in welding fluxes. Thermodynamic calculations were conducted to determine optimal reaction temperatures and experimental conditions. Rutile and sodium carbonate were roasted at different temperatures, holding times, and concentration ratios to produce sodium titanate. X-ray diffraction was used to analyze the produced phases. Sodium titanate samples were added to welding fluxes and the effects on arc stability were evaluated visually and through sensors during arc welding tests. The results showed that roasting rutile and sodium carbonate at a ratio of 1.5:1 at 900°C for 2 hours produced phases of Na2Ti3O7 and Na2Ti3
Fatigue Analysis of Acetylene converter reactorIJMER
The structural integrity of mechanical components during several transients should be
assured in the design stage. This requires a fatigue analysis including thermal and structural analysis. As
an example, this study performs a fatigue analysis of the acetylene converter reactor during arbitrary
transients. Using heat transfer coefficients determined based on the operating environments, a transient
thermal analysis is performed and the results are applied to a finite element model along with the
pressure to calculate the stresses. The total stress intensity range and cumulative fatigue usage factor are
investigated to determine the adequacy of the design.
Validation of a Model for Ice Formation around Finned TubesIJERA Editor
This document validates a numerical model for ice formation around finned tubes used in latent heat storage systems. Experiments were conducted using a test apparatus to measure ice formation rates and patterns during solidification of water around finned tubes. The numerical model, which is based on conduction and the enthalpy method, was found to predict the experimental results with reasonably good agreement. Comparisons of predicted and measured interface velocities, solidified mass fractions, and radial interface positions validated the model's ability to simulate the solidification process around finned tubes. This confirms finned tubes can enhance the thermal performance of phase change materials for thermal energy storage applications.
Experimental Study of Heat Transfer Enhancement in Triple Tube Heat Exchanger...IRJET Journal
The document describes an experimental study of heat transfer enhancement in a triple tube heat exchanger using CuO and Al2O3 nanofluids. A triple tube heat exchanger was tested with hot water flowing through the intermediate tube and cold water flowing through the inner and outer tubes. Nanofluids of CuO and Al2O3 with a 0.033% volumetric concentration were used. The heat transfer rate and effectiveness of the triple tube heat exchanger were evaluated experimentally for different flow rates of the hot fluid, with the cold fluid flow rate held constant. The results showed that use of nanofluids increased the heat transfer rate and effectiveness compared to using plain water as the working fluid.
ANALYSIS OF HEAT TRANSFER CHARACTERISTICS IN CROSS FLOW PLATE FIN TYPE HEAT E...IRJET Journal
This document summarizes an analysis of heat transfer characteristics in a cross-flow plate fin heat exchanger using non-Newtonian fluids. The study used a cross-flow plate fin heat exchanger constructed of aluminum with corrugated fins to transfer heat between hot water and cold fluids of varying concentrations of carboxy methyl cellulose (CMC). Experiments were conducted at different flow rates and CMC concentrations to determine parameters such as heat transfer coefficients, effectiveness, and heat transfer performance. Results showed that increasing CMC concentration and flow rate affected these parameters.
IRJET- Anlysis based on CFD Study of Different Turbulent Parameters for a Rad...IRJET Journal
This document presents a computational fluid dynamics (CFD) analysis of heat transfer and turbulent parameters for a radiator with louvered fins. The study examines varying the louver angle (24 and 29 degrees) and inlet velocity (4-8 m/s). Results show that increasing the louver angle and inlet velocity leads to higher heat transfer rates, turbulent energy, and turbulent viscosity. The 29 degree louver angle produces better results than the 24 degree angle across all parameters and velocities. The analysis provides design guidance for optimizing louvered fin geometry in radiators.
A REVIEW PAPER ON ANALYSIS OF AUTOMOBILE RADIATORijsrd.com
An Automotive engine cooling system takes out of excess heat produced during engine operation. An automobile cooling system regulates engine surface temperature for engine optimum efficiency. Recent advancement and development in engine for power forced engine cooling system to develop new strategies to improve its performance efficiency. Also to reduce fuel consumption along with controlling engine emission to mitigate environmental pollution norms. This paper throws light on parameters which influence radiator performance along with reviews some of the conventional and modern approaches to enhance radiator performance. This review paper Focus on the various research papers regarding experimental, CFD and Numerical analysis to improving automobile radiator efficiency.
A Review Paper On Analysis Of Automobile RadiatorCarrie Tran
The document reviews research on improving the performance of automobile radiators. It discusses several studies that analyzed radiator performance using computational fluid dynamics (CFD) simulations and experiments with nanofluids (liquids with suspended nanoparticles) as coolants. The studies found that using nanofluids as coolants can enhance heat transfer and improve radiator efficiency compared to conventional coolants like water and ethylene glycol mixtures. Some nanofluids that increased radiator performance included those with copper oxide, aluminum oxide, titanium dioxide, and silicon carbide nanoparticles. The document summarizes various approaches for optimizing radiator design and coolant properties to improve cooling capacity while reducing energy consumption.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology.
Experimental Optimization of Capillary Tube in Domestic Refrigeratorpaperpublications3
Abstract: This paper describes the experimental optimization of capillary tube for choosing best suitable capillary in domestic refrigerator and comparison in performance of two different refrigerants (R134a and R600a). This experiment deals with optimization performance testing for a domestic refrigerator using experimental method.
This document discusses thermo-analytical techniques, specifically thermogravimetric analysis (TGA). It begins with an introduction to thermo-analytical methods and defines the difference between these methods and traditional analytical techniques. TGA is then explained in more detail, including the principles behind how it works, instrumentation involved consisting of a thermo-balance, furnace, and recording device, and factors that can affect TGA results such as sample characteristics and instrumental factors. Applications of TGA include stability studies, oxidation reactions, and pharmacokinetics studies.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document presents a numerical analysis of heat transfer enhancement in pipe-in-pipe helical coiled heat exchangers. A computational fluid dynamics (CFD) analysis was conducted to determine the effect of varying parameters like inner tube diameter, mass flow rates, and flow configuration (parallel vs. counter flow) on heat transfer characteristics. The CFD results showed that decreasing the inner tube diameter and increasing the mass flow rates led to higher overall heat transfer coefficients. Counter flow configuration provided better heat transfer than parallel flow. Validation of the CFD model showed decent agreement with existing empirical correlations for heat transfer in helical coils.
The binding of cosmological structures by massless topological defectsSérgio Sacani
Assuming spherical symmetry and weak field, it is shown that if one solves the Poisson equation or the Einstein field
equations sourced by a topological defect, i.e. a singularity of a very specific form, the result is a localized gravitational
field capable of driving flat rotation (i.e. Keplerian circular orbits at a constant speed for all radii) of test masses on a thin
spherical shell without any underlying mass. Moreover, a large-scale structure which exploits this solution by assembling
concentrically a number of such topological defects can establish a flat stellar or galactic rotation curve, and can also deflect
light in the same manner as an equipotential (isothermal) sphere. Thus, the need for dark matter or modified gravity theory is
mitigated, at least in part.
EWOCS-I: The catalog of X-ray sources in Westerlund 1 from the Extended Weste...Sérgio Sacani
Context. With a mass exceeding several 104 M⊙ and a rich and dense population of massive stars, supermassive young star clusters
represent the most massive star-forming environment that is dominated by the feedback from massive stars and gravitational interactions
among stars.
Aims. In this paper we present the Extended Westerlund 1 and 2 Open Clusters Survey (EWOCS) project, which aims to investigate
the influence of the starburst environment on the formation of stars and planets, and on the evolution of both low and high mass stars.
The primary targets of this project are Westerlund 1 and 2, the closest supermassive star clusters to the Sun.
Methods. The project is based primarily on recent observations conducted with the Chandra and JWST observatories. Specifically,
the Chandra survey of Westerlund 1 consists of 36 new ACIS-I observations, nearly co-pointed, for a total exposure time of 1 Msec.
Additionally, we included 8 archival Chandra/ACIS-S observations. This paper presents the resulting catalog of X-ray sources within
and around Westerlund 1. Sources were detected by combining various existing methods, and photon extraction and source validation
were carried out using the ACIS-Extract software.
Results. The EWOCS X-ray catalog comprises 5963 validated sources out of the 9420 initially provided to ACIS-Extract, reaching a
photon flux threshold of approximately 2 × 10−8 photons cm−2
s
−1
. The X-ray sources exhibit a highly concentrated spatial distribution,
with 1075 sources located within the central 1 arcmin. We have successfully detected X-ray emissions from 126 out of the 166 known
massive stars of the cluster, and we have collected over 71 000 photons from the magnetar CXO J164710.20-455217.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
Travis Hills' Endeavors in Minnesota: Fostering Environmental and Economic Pr...Travis Hills MN
Travis Hills of Minnesota developed a method to convert waste into high-value dry fertilizer, significantly enriching soil quality. By providing farmers with a valuable resource derived from waste, Travis Hills helps enhance farm profitability while promoting environmental stewardship. Travis Hills' sustainable practices lead to cost savings and increased revenue for farmers by improving resource efficiency and reducing waste.
Authoring a personal GPT for your research and practice: How we created the Q...Leonel Morgado
Thematic analysis in qualitative research is a time-consuming and systematic task, typically done using teams. Team members must ground their activities on common understandings of the major concepts underlying the thematic analysis, and define criteria for its development. However, conceptual misunderstandings, equivocations, and lack of adherence to criteria are challenges to the quality and speed of this process. Given the distributed and uncertain nature of this process, we wondered if the tasks in thematic analysis could be supported by readily available artificial intelligence chatbots. Our early efforts point to potential benefits: not just saving time in the coding process but better adherence to criteria and grounding, by increasing triangulation between humans and artificial intelligence. This tutorial will provide a description and demonstration of the process we followed, as two academic researchers, to develop a custom ChatGPT to assist with qualitative coding in the thematic data analysis process of immersive learning accounts in a survey of the academic literature: QUAL-E Immersive Learning Thematic Analysis Helper. In the hands-on time, participants will try out QUAL-E and develop their ideas for their own qualitative coding ChatGPT. Participants that have the paid ChatGPT Plus subscription can create a draft of their assistants. The organizers will provide course materials and slide deck that participants will be able to utilize to continue development of their custom GPT. The paid subscription to ChatGPT Plus is not required to participate in this workshop, just for trying out personal GPTs during it.
The technology uses reclaimed CO₂ as the dyeing medium in a closed loop process. When pressurized, CO₂ becomes supercritical (SC-CO₂). In this state CO₂ has a very high solvent power, allowing the dye to dissolve easily.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
ESR spectroscopy in liquid food and beverages.pptxPRIYANKA PATEL
With increasing population, people need to rely on packaged food stuffs. Packaging of food materials requires the preservation of food. There are various methods for the treatment of food to preserve them and irradiation treatment of food is one of them. It is the most common and the most harmless method for the food preservation as it does not alter the necessary micronutrients of food materials. Although irradiated food doesn’t cause any harm to the human health but still the quality assessment of food is required to provide consumers with necessary information about the food. ESR spectroscopy is the most sophisticated way to investigate the quality of the food and the free radicals induced during the processing of the food. ESR spin trapping technique is useful for the detection of highly unstable radicals in the food. The antioxidant capability of liquid food and beverages in mainly performed by spin trapping technique.
ESR spectroscopy in liquid food and beverages.pptx
Anilkumar2007
1. International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
www.elsevier.com/locate/ijhydene
Influenceoftransient operating conditionson pressure-concentration
isothermsand storage characteristics ofhydridingalloys
E. Anil Kumar, M. Prakash Maiya, S. Srinivasa Murthy ∗
Refrigeration and Air Conditioning Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai - 600 036, India
Received 11 August 2006; received in revised form 9 October 2006; accepted 9 October 2006
Available online 28 November 2006
Abstract
Pressure-concentration isotherms (PCI) are measured by both static and dynamic methods for mischmetal based alloys, MmNi3.9 Co0.6 Al0.5
and MmNi4 Al. The effects of hydrogen flow rate on plateau pressure, enthalpy of formation and entropy of formation are studied. For
MmNi3.9Co0.6Al0.5 both shape of the PCI and plateau pressureare dependent on the flow rate. The effect on plateau pressureis not significant
in the case of MmNi4 Al. Both materials showed significant variations in enthalpy of formation with flow rate due to variation in reaction
rate. The effect of flow rate on desorption isotherm is negligible as the desorption equilibrium pressure is much lower compared to absorption
equilibrium pressure due to large hysteresis in these materials. While the basic nature of variation of pressure with concentration is same for
both static and dynamic PCIs, the thermodynamic properties estimated based on these data vary significantly.
2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
Keywords: Metal hydride; Dynamic PCI characteristics; Enthalpy of formation; Entropy of formation
1. Introduction
Hydriding materials can be synthesized in a variety of com-
positions to suit the hydriding and dehydriding characteris-
tics required for specific applications. Pressure-concentration
isotherms (PCI) represent hydrogen gas pressure in thermody-
namic equilibrium with a metal and its hydride as a function
of hydrogen concentration at a given temperature.
PCI can be obtained by both static and dynamic means. In
static measurement, a given amount of hydrogen is added or
withdrawn stepwise from the system. At the end of each step,
equilibrium condition is established. In dynamic measurement,
hydrogen mass flow rate is maintained constant throughout
the experiment. For the design of metal hydride based systems
like hydrogen storage devices, heat pumps, heat transformers,
thermal compressors etc., static PCI data is not suitable due
to dynamic operating conditions. For instance, if a hydrogen
compressoris designed using static PCI data, the actual driving
temperature has to be somewhat higher than the static design
∗ Corresponding author. Fax: +91 44 2257 0545/4652.
E-mail address: ssmurthy@iitm.ac.in (S. Srinivasa Murthy).
temperature to reach the designed hydrogen pressure [1].
Tuscher et al. [2] tested single and double bed storage units
containing LaNi4.6 Al0.4 as hydrogen storage material with re-
gard to their dynamic behaviour in energy conversion systems.
The dynamic quasi-isotherms showed an increase in hystere-
sis with increase in hydrogen sorption rates. They measured
the total hydrogen flow and hydrogen pressure at various
half-cycle times with coolant (water) at 286 and 353 K. The
operating characteristics of the system showed that the effi-
ciency of energy conversion decreases with increasing hydro-
gen flow. Nagel et al. [3] studied the dynamic PCI behaviour
of the paired metal hydrides MmNi4 Fe and LaNi4.65 Al0.3 .
They observed that dynamic PCI showed more clearly the actual
hydrogen content of the paired hydride than the static PCI
curve. Published data on PCI [4–6] reveal that the plateau
pressures in dynamic PCI measurement depend on the reaction
rate. Detailed discussion on PCI measurements and material
characteristics are given in Ref. [7].
With the above mentioned points in view, two mischmetal
based materials are studied here for effect of flow rate
on PCI, thermodynamic and storage properties at different
temperatures.
0360-3199 /$ - see front matter 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.ijhydene.2006.10.041
2. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23832383 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
4
Nomenclature
ma mass of hydrogen absorbed by metal hydride
in static experiments, g
malloy mass of alloy sample charged in the reactor, g
mf mass of hydrogen expanded as free gas in to
the reactor, g
mia mass ofhydrogen absorbed by metalalloy till
a particular instant in dynamic experiments,
g
mif mass of free gas, g
miT total mass of hydrogen transferred through
mass flow controller till a particular instant,g
mT mass of hydrogen entered in to the reactor in
static experiments, g
P differential pressure transducer reading,
N/m2
Pi pressure in volume upstreamof the reactorat
any instant, N/m2
Praa reactor pressure after absorption,N/m2
Prba reactor pressure before absorption, N/m2
Ps pressure at standard conditions, N/m2
Qit total volume of hydrogen transferred through
mass flow controller till a particular instant,m3
R characteristic gas constant,4.124 J/g K of H2
T1 temperature of hydrogen gas in selected volume,
K
T4 temperature of hydrogen gas in the reactor, K
Ti2 temperature of hydrogen gas in the volume up-
stream of the reactor at any instant, K
Ti3 temperature of hydrogen gas in reactor void vol-
ume at any instant, K
Ts temperature at standard conditions,K
Vf volume upstream of the reactor, m3
VRd void volume of reactor in dynamic measure-
ments, m3
VRs void volume inside the reactorin static measure-
ments, m3
Vs selected volume (volume from where hydrogen
is supplied/desorbed in static experiments), m3
wH storage capacity, %
Z compressibility factor
Fig. 1. Schematic of experimental set-up for static PCI measurements.
2. Experimental setup
The set-up for measuring the static PCI characteristics of
metal hydride alloys is illustrated in Fig. 1. A cylindrical reac-
tor of 15 mm inner diameter and 2 mm thickness as shown in
Fig. 2 is used for the static PCI measurements. One end of the
reactor is closed with a provision for connecting a thermocou-
ple, while the other end is threaded with an end cap, which is
further welded to a 1 ∗∗
SS-tube for hydrogen supply.Only half
volume of the reactor is filled with the alloy. It is ensured that
the hydrogen supply tube is in the upper half of the reactor
so that the hydrogen gas can flow till the other end of the re-
actor and diffuse uniformly downwards maintaining uniform
absorption rate through the entire length of the bed. Piezo re-
sistive type pressure transducers P1 and P2 of range 0–100 bar
are used for measuring the supply pressure and P3 is used for
measuring the hydride equilibrium pressure. Differential pres-
sure (DP) transducer of range 0.5 bar is used for measuring
3. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23842384 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
Fig. 2. Reactor for static PCI measurements.
Fig. 3. Schematic of experimental set-up for dynamic PCI measurements.
the pressure difference between the reference and the selected
volumes. “K” type thermocouples of accuracy ±1 ◦
C and a
time constant of 0.2 s are used for measuring the temperature
of hydrogen gas at different locations as shown in Fig. 1. Ther-
mostatic oven of range 27.350 ◦
C is used for supplying heat
during desorption and also used for maintaining a constant tem-
perature environment for the reactor. A digital Pirani gauge of
accuracy ±0.5% is used for measuring the vacuum.
The set-up for measuring the dynamic PCI characteristics il-
lustrated in Fig. 3 is similar to static PCI measurement set-up
in many features. Differences between two setups are, the dy-
namic setup consists of a thermal mass flow controller (MFC)
and a thermostatic bath instead of the DP transducer and con-
stant temperature oven. A cylindrical reactor of 15 mm inner
diameter and 2 mm thickness as shown in Fig. 4 is used for the
dynamic PCI measurements. One end of the reactor is closed,
while the other end of the reactor is threaded with an end cap,
so that the reactor can be charged with metal alloy through this
end. The dynamic reactor is also half filled like the static re-
actor. Two piezo resistive type pressure transducers P1, P2 of
range 0.100 bar are used for measuring hydrogen supply pres-
sure and reactorpressure respectively.The mass flowcontroller
of range 0.100 ml/ min is used to supply hydrogen at a con-
stant mass flow rate to the reactor.A thermostatic bath of range
0.100 ◦
C is used to maintain isothermal conditions for the re-
actor in spite of continuous release or absorption of reaction
enthalpy.
3. Choice and preparation of alloy
Low pressure AB5 type mischmetal based alloys find a va-
riety of applications such as hydrogen storage, metal hydride
batteries, water pumping systems etc. Detailed studies on the
effects of mass flow rate on dynamic PCI measurements for
the low pressure alloys are not available. Here two well-known
low pressure AB5 mischmetal based alloys MmNi4 Al and
MmNi3.9 Co0.5 Al0.6 are chosen. Both the alloys were synthe-
sised [8] at Defence Metallurgical Research Laboratory, Hy-
derabad and delivered as powder with an average particle size
of 50 m. Alloy samples of 20 g each are used for testing after
activation. Activation procedure consists of evacuation down to
10−3
mbar at 120 ◦
C and charging with hydrogen at a pressure
of 20 bar and room temperature. The evacuation and charging
is repeated for 20 cycles to complete the activation procedure.
4. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23852385 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
m =
m =
Mass of hydrogen absorbed by metal alloy
ma = mT − mf . (4)
Hence storage capacity
ma
wH (wt%) =
malloy
× 100. (5)
Fig. 4. Reactor for dynamic PCI measurements.
4. Experimental procedure
In the case of static PCI measurement during absorption,
a given amount of hydrogen is added to the sample of metal
powder in steps.Any one or two or all the three of CC1 , CC2
and CC3 (Fig. 1) are put into operation by valves v1, v2 and
v3 depending on prior experience about the absorption capac-
ity of the powder. This is necessary to keep the pressure dif-
ference across DP (which is used to reduce the error) within
a limit after absorption in each step.All the valves except v8,
v11, v12 and v13 are opened and hydrogen is introduced to the
system. Then valve v5 is closed. Pipe volumes V4 , V5 and cali-
brated cylinder CC4 together act as reference volume. It’s tem-
To get wH at higher pressures,valve v8 is closed, v5 is opened
and hydrogen is charged via v10 to the predetermined high
pressure.The procedure is repeated to find the wt% at the cor-
responding equilibrium pressure. The experiment is continued
till a maximum wt% is reached (i.e. till there is no significant
difference in wt% two successive steps). Similar procedure is
adopted to find the wt% during desorption stages as well.
In the case of dynamic PCI measurement during absorption,
hydrogen gas is introduced at a predetermined rate by using
MFC (Fig. 3). The gas is allowed to get absorbed simultane-
ously by the sample of metal powder in the reactor maintained
at constant temperature. Valves v3, v4, v5, v7 and v8 are opened
and all the remaining valves are closed. Pressure and tempera-
ture in the upstream of the reactor (pipe volume between v6, v8,
v9, v10 and MFC) are measured continuously to estimate the
free gas in this volume at any instant of time. The same pres-
sure is assumed to prevail in the reactor while its temperature is
continuously monitored (to account for minor changes) to esti-
mate the free hydrogen occupied in its void volume. Thus at any
instant of time hydrogen fed to the control volume is given by
Ps
perature and hence pressure remains constant during each step
of experiment. Valve v8 is opened.Hydrogen gets absorbed in
miT = QiT
RT s
. (6)
the sample of metal powder. After reaching the equilibrium the
pressure drop is measured from DP.
Free hydrogen gas in the control volume:
Amount of hydrogen transferred to the reactor: PiVf
if
ZRT i2
PiVRd
+
ZRT i3
. (7)
P Vs
T
ZRT 1
, (1) Actual amount of hydrogen absorbed:
mia = miT − mif . (8)
where
Z = f (p, T ) = 1 + (B0 + B1 T + B2 T2
)P × 10−6
Hence storage capacity:
m
+ (C0 + C1T + C2T 2
)P 2
× 10−12
, (2)
wH (wt%) =
ia
malloy
× 100. (9)
B0 = 0.00962 MPa−1
,
B1 = −15.446 × 10−9
MPa−1
K−1
,
B2 = 82.314 × 10−13
MPa−1
K−2
,
C0 = 18.167 × 10−8
MPa−2
,
C1 = −83.222 × 10−11
MPa−2
K−1
,
C2 = 9.327 × 10−13
MPa−2
K−2
. Amount of free gas in
the reactor
5. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23862386 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
Experiment is repeated with different
flow rates of hydrogen through MFC
as well as different reactor
temperatures generat- ing a family of
absorption curves. Similar procedure
is adopted for finding desorption
characteristics as well by
appropriately operating various
valves.A vacuum pump is employed
for desorption at sub atmospheric pressures.
The van’t Hoff plot of the metal hydride is obtained by plot-
ting logarithm of equilibrium pressures (the pressure at mid
plateau) against the corresponding reciprocal of temperatures
(in Kelvin). An equation is fitted to the line so obtained. By
comparing the equation of fit (ln Pe = A/ T + B) with van’t
Hoff’s equation (ln Pe = H/RT − S/R), i.e., A = H /R
and B = S/R, the two thermodynamic properties namely
mf =
Prba VRs
ZRT 4
Praa VRs
−
ZRT 4
. (3)
enthalpy of formation ( H) and entropy of formation ( S)
are evaluated.
6. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23872387 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
Pressure(bar)Pressure(bar)
Pressure(bar)Pressure(bar)
100
10
1
0.1
0.01
Absor p tio n
80ºC
60ºC
40ºC
27ºC
80ºC
60ºC
40ºC
27ºC
Desorption
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
100
10
1
0.1
0.01
Absor p t io n
80°C
60°C
40°C
27°C
80°C
60°C
40°C
27°C
Deso r p tio n
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
Fig. 5. Static PCI curves for MmNi3.9 Co0.5 Al0.6 .
Fig. 7. Dynamic PCI curves for MmNi3.9 Co0.5 Al0.6 at 80 ml/min.
100
10
1
0.1
0.01
Absorption
80°C
60°C
40°C
27°C
80°C
60°C
40°C
27°C
Desorption
100
10
1
0.1
0.01
Absorption
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
De sorption
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
Fig. 6. Dynamic PCI curves for MmNi3.9 Co0.5 Al0.6 at a flow rate of
20 ml/min.
A least square analysis is made to find the error limits. The
maximum errors in calculating wt% are ±3 and ±3.5% for
static and dynamic measurements, respectively. Further, the
maximum errors in estimated values H and S are ±5.75
and ±5.65%, respectively.
5. Results and discussion
The static PCI characteristics of MmNi3.9 Co0.5 Al0.6 are
shown in Fig. 5. It is observed that the hydride is a low-pressure
alloy as the plateau pressure is around 1 bar up to 80 ◦
C.
MmNi3.9 Co0.5 Al0.6 reached a maximum storage capacity of
1.3 wt% at 27 ◦
C. The isotherms showed a large plateau slope
as pressure during absorption varies from sub atmospheric to
10 bar absolute at all temperatures which is a characteristic of
all AB5 materials. Higher absorption temperature considerably
reduces the storage capacity due to larger plateau slope. Fig. 6
shows the dynamic PCI isotherms at 20 ml/min. It is observed
that the shapes of the static and dynamic isotherms are similar.
However, in static PCI for a given temperature, the pressure
hysteresis between absorption and desorption is not significant.
But the dynamic PCI curve exhibits greater hysteresis than the
7. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23882388 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
Fig. 8. Comparison of static and dynamic isotherms at 27◦C for
MmNi3.9 Co0.5 Al0.6 .
static curve. There is no significant difference in the storage
capacities.
The isotherm at 27 ◦
C exhibits larger slope. Thus the plateau
pressure and shape of isotherms depend on the mass flow rate.
In dynamic PCI measurement a fixed amount of hydrogen is al-
lowed through the MFC. This flow rate may differ from the rate
of absorption. Hence driving force for reaction rate is not the
difference between the supply and bed pressures but the rate at
which hydrogen is transferred through the MFC. Thus the reac-
tion rate is slowat lower mass flow rate and increases up to max-
imum possible absorption rate with increasing mass flow rate.
The absorption at 80ml/min takes about 60min while about
250 min is necessary for a flow rate of 20 ml/min. The maxi-
mum deviations in temperature in the metal hydride bed during
absorption/desorption are about 1.5 and 3 ◦
C at low (20 ml/min)
and high (80 ml/min) flow rates, respectively. The maximu m
deviation in temperature occurs during absorption/desorption
at the middle of the plateau.
Fig. 7 shows dynamic PCI for MmNi3.9 Co0.5 Al0.6 at a flow
rate of80 ml/min. Isotherms at 27 and 40 ◦C showgreaterslopes
than those at 60 and 80◦
C. This is due to low absorption rate
at lower temperatures. Fig. 8 compares the static and dynamic
8. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23892389 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389Pressure(bar)Pressure(bar)
lnPePressure(bar)
100
10
1
0.1
Absorption
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
Desorption
100
10
1
0.1
Absorption
ml/min
80
60
40
20
ml/min
80
60
40
20
Desorption
0.01
0 0.2 0.4 0.6 0.8 1 1.2
Storage Capacity (wt%)
0.01
0 0.2 0.4 0.6 0.8 1 1.2
Storage Capacity (wt%)
Fig. 9. Comparison of static and dynamic isotherms at 80 ◦C for
MmNi3.9 Co0.5 Al06 .
Fig. 11. Effect of flow rate on plateau pressure at 80 ◦C for
MmNi3.9 Co0.5 Al0.6 .
100
10
Absorption
ml/min
80
60
40
1
0.5
0
Static
20 ml/min
40 ml/min
60 ml/min
80 ml/min
Dynamic
1
0.1
20
ml/min
80
60
40
20
Desorption
-0.5
-1
-1.5
-2
LnPe
= -3867.1x + 10.611
LnPe
= -3975.1/T + 11.071
LnPe
= -4299.9/T + 12.656
LnPe
= -4177.5/T + 12.058
0.01
0 0.2 0.4 0.6 0.8 1 1.2 1.4 -2.5
LnPe
= -4055.8/T + 11.447
Storage Capacity (wt%)
Fig. 10. Effect of flow rate on plateau pressure at 27 ◦C for
MmNi3.9 Co0.5 Al0.6 .
isotherms at 27 ◦C and clearly shows that dynamic PCI exhibits
higher slope and hysteresis compared to static values. These
also increase with increase in flow rate. Fig. 9 shows that dy-
namic absorption isotherm at 20 ml/min coincides with static
PCI. At higher flow rates, the hysteresis is higher as desorp-
tion occurs at lower pressure and absorption occurs at higher
pressure.At higher flow rate there is also a decrease in hydro-
gen capacity. Fig. 10, which shows absorption and desorption
isotherms at 27 ◦
C for different flow rates, reveals that the ab-
sorption curve at 20 ml/min has flat plateau compared to others.
As mass flow rate increases the plateau slope also increases.
This is because, the increase in bed temperature is higher at
higher flow rates. At lower mass flow rates the sample has more
time to reach thermodynamic equilibrium whereas at higher
flow rates accumulation of hydrogen occurs in the reactor if the
amount of hydrogen entering exceeds the absorption rate. It is
observed that the maximum hydrogen capacity also decreases
with increase in flow rate. Fig. 11 shows that the plateau slope
at 80 ◦
C is almost same at all flow rates due to faster kinetics.
However, absorption plateau pressure increases with flow rate
and the maximum amount of hydrogen absorbed decreases with
9. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23902390 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
0.0028 0.0029 0.003 0.0031 0.0032 0.0033 0.0034
1/T (1/K)
Fig. 12. Van’t Hoff plots for MmNi3.9 Co0.5 Al0.6 .
flow rate. The effect of flow rate is negligible on desorption
plateau pressure at all temperatures. Fig. 12 shows the van’t
Hoff plots drawn from static PCI and dynamic data at different
flow rates. It is seen that the line of intercept increases with flow
rate and is the lowest for static PCI. The slope also increases
with flow rate which influences the value of the enthalpy of for-
mation. In the present study, the enthalpy of formation varies
from 32.15 to 35.75 kJ/mol H2 .
The static PCI characteristics of MmNi4 Al shown in Fig. 13
reveal that this low-pressure alloy attains a maximum storage
capacity of 1.3 wt% at 27 ◦
C. The isotherms also show greater
slope which increases with increase in temperature. Fig. 14
shows that the dependence of plateau pressure on flow rate
is much lower when compared to MmNi3.9 Co0.5 Al0.6 as it
shows well defined plateau regions even at low temperature
and high flow rate. The plateau slope is nearly constant with
variation in flow rate, which suggests high nucleation rate of
new phases for this material. Fig. 15 shows PCI at a high flow
rate of 80 ml/min and no pressure over shoot is observed even
at lower temperatures due to the above effect. Fig. 16 makes
a comparison of static and dynamic isotherms at 27 ◦C. The
10. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23912391 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
Pressure(bar)Pressure(bar)Pressure(bar)
Pressure(bar)Pressure(bar)Pressure(bar)
100 100
10
1
0.1
Absor p t io n
80°C
60°C
40°C
27°C
80°C
60°C
40°C
27°C
Desorption
10
1
0.1
0.01
Absorption
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
Desorption
0.01
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
Fig. 13. Static PCI curves for MmNi4 Al.
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
Fig. 16. Comparison of static and dynamic isotherms at 27◦C for MmNi4 Al.
100
10
1
0.1
Absor p tio n
80°C
60°C
40°C
27°C
80°C
60°C
40°C
27°C
Desorption
100
10
1
0.1
Absorption
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
80 ml/min (Dyn)
20 ml/min (Dyn)
Static
Desorption
0.01
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
0.01
0 0.2 0.4 0.6 0.8 1 1.2
Storage Capacity (wt%)
Fig. 14. Dynamic PCI curves for MmNi4 Al at 20 ml/min.
Fig. 17. Comparison of static and dynamic isotherms at 80◦C for MmNi4 Al.
100
10
1
0.1
Absor p t io n
80°C
60°C
40°C
27°C
80°C
60°C
40°C
27°C
Desorption
100
10
1
0.1
0.01
Absorption
ml/min
80
60
40
20
ml/min
80
60
40
20
Desorption
0.01
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity (wt%)
0 0.2 0.4 0.6 0.8 1 1.2 1.4
Storage Capacity(wt%)
Fig. 18. Effect of flow rate on plateau pressure at 27 ◦C for MmNi4 Al.
Fig. 15. Dynamic PCI curves for MmNi4 Al at 80 ml/min.
11. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23922392 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389
dynamic PCI reveals higher hysteresis and plateau slope com-
pared to static PCI. However, unlike MmNi3.9 Co0.5 Al0.6 , the
shape of the curve is not distorted.Fig. 17 shows comparison of
static and dynamic isotherms at a higher temperature of 80 ◦
C.
Figs. 18 and 19 show the effects of flow rate on plateau
pressure at 27 and 80 ◦
C, respectively. It is observed that there
is no significant effect of flow rate on plateau pressure at both
the temperatures, except for a small increase at 80 ml/min at
80 ◦
C. Fig. 20 shows the van’t Hoff plots at different flow
rates. The variation in enthalpy of formation is less (26.6 to
27.1 kJ/mol H2 ) compared to that of MmNi3.9 Co0.5 Al0.6 .
12. E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389 23932393 E. Anil Kumar et al. / International Journal of Hydrogen Energy 32 (2007) 2382 – 2389Pressure(bar)Ln(Pe)
100
10
1
0.1
0.01
Absorption
ml/min
80
60
40
20
ml/m in
80
60
40
20
Deso r p tio n
• The dynamic PCI depends on hydrogen flow rate. The ef-
fect of flow rate is less for material with faster kinetics. The
effect of flow rate on property evaluation is negligible for
MmNi4 Al which is expected to have faster kinetics com-
pared to MmNi3.9 Co0.5 Al0.6 .
• There is significant variation in enthalpy of formation from
static to dynamic measurements and with variation of flow
rate. The variation in entropy of formation is negligible.
• To obtain the most suitable data for a particular applica-
tion the flow rate should be nearer to the average absorp-
tion/desorption rates.
0 0.2 0.4 0.6 0.8 1 1.2
Storage Capacity (wt%)
Fig. 19. Effect of flow rate on plateau pressure at 80◦C for MmNi4 Al.
1.3
Static
20ml
Acknowledgements
This work has been financially supported by Ministry of
Non-conventional Energy Sources, Government of India. The
authors thank Dr. G. Balachandran, Scientist, and the Director,
Defence Metallurgical Research Laboratory for providing the
0.8 LnPe
= -3256.8x + 9.7189 40ml
60ml
80ml
Dynamic
alloys.
0.3
-0.2
-0.7
-1.2
LnPe = -3237.2x + 9.6367
LnPe
= -3213x + 9.2004 LnPe
= -3227.9x + 9.4147
LnPe
= -3197x + 9.1336
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Fig. 20. Van’t Hoff plots for MmNi4 Al.
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• MmN i3.9 Co0.5 Al0.6 and MmNi4 Al are observed as lowpres-
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