This paper addresses the numerical simulation of
helically coiled closed loop pulsating heat pipe which is carried
in ANSYS Fluent. The values of thermal resistance for
constant heat fluxes vs. transient heat fluxes are analyzed.
Phase change visualization after the end of simulation is
carried out to observe the phenomenon in liquid at its
saturation temperature and pressure. Finally, helical heat
pipes are found to have thermal resistance less by 2.7K/W,
0.56 K/W, and 0.227 K/W for 8W, 40W and 80W heat inputs
than circular pipes. Helical heat pipes are found more efficient
than circular heat pipes.
Storing latent heat with liquid crystals (13th european conference on liquid ...Jokin Hidalgo
Thermal energy storage a key element in thermal
processes management especially in those related
to renewable energies. When processes entail
water condensation/evaporation, the best approach
is storing energy as latent heat with phase change
materials (PCM’s) that undergo state transitions at
temperatures close to the steam working conditions
(i.e. 140ºC-340 ºC). Current PCM’s exhibit solid to
liquid transitions and have a very poor thermal
conductivity Power density of the whole storage
is reduced and power in discharge is not constant.
Solar air heater (SAH), which is the most essential component of solar drying systems, receive solar energy and convert it into thermal energy. This review presents descriptions and previous works conducted on performances analysis of SAHs. Exergoenviroeconomic, exergoenvironmental, environmental, and exergy analyses are also presented. In addition, results on the performances of SAHs are summarized. The exergy and energy efficiencies of SAHs at laboratorium testing range from 8% to 61% and from 30% to 79%, respectively.
The objective of this experiment is to calculate the rate of the heat transfer log mean temperature difference, and the overall heat transfer coefficient in case of Counter flow
Experimental Investigation of a Helical Coil Heat Exchangerinventy
Helical coil heat exchangers are one of the most common equipment found in many industrial applications. Helical coil heat exchanger is one of the devices which are used for the recovery system. The helical coil heat exchangers can be made in the form of a shell and tube heat exchangers and can be used for industrial applications such as power generation, nuclear industry, process plants, heat recovery systems, refrigeration, food industry etc. In our work we had designed, fabricated and experimentally analysed a helical coil heat exchanger and a straight tube heat exchanger. From the observations and calculations, the results of the helical coil heat exchanger and straight tube heat exchanger are obtained and are compared. From our obtained results, the helical coil heat exchanger showed increase in the heat transfer rate, effectiveness and overall heat transfer coefficient over the straight tube heat exchanger on all mass flow rates and operating conditions. The centrifugal force due to the curvature of the tube results in the secondary flow development which enhances the heat transfer rate. Comparative study shows that helical coil heat exchanger is having better performance that straight tube heat exchanger.
Storing latent heat with liquid crystals (13th european conference on liquid ...Jokin Hidalgo
Thermal energy storage a key element in thermal
processes management especially in those related
to renewable energies. When processes entail
water condensation/evaporation, the best approach
is storing energy as latent heat with phase change
materials (PCM’s) that undergo state transitions at
temperatures close to the steam working conditions
(i.e. 140ºC-340 ºC). Current PCM’s exhibit solid to
liquid transitions and have a very poor thermal
conductivity Power density of the whole storage
is reduced and power in discharge is not constant.
Solar air heater (SAH), which is the most essential component of solar drying systems, receive solar energy and convert it into thermal energy. This review presents descriptions and previous works conducted on performances analysis of SAHs. Exergoenviroeconomic, exergoenvironmental, environmental, and exergy analyses are also presented. In addition, results on the performances of SAHs are summarized. The exergy and energy efficiencies of SAHs at laboratorium testing range from 8% to 61% and from 30% to 79%, respectively.
The objective of this experiment is to calculate the rate of the heat transfer log mean temperature difference, and the overall heat transfer coefficient in case of Counter flow
Experimental Investigation of a Helical Coil Heat Exchangerinventy
Helical coil heat exchangers are one of the most common equipment found in many industrial applications. Helical coil heat exchanger is one of the devices which are used for the recovery system. The helical coil heat exchangers can be made in the form of a shell and tube heat exchangers and can be used for industrial applications such as power generation, nuclear industry, process plants, heat recovery systems, refrigeration, food industry etc. In our work we had designed, fabricated and experimentally analysed a helical coil heat exchanger and a straight tube heat exchanger. From the observations and calculations, the results of the helical coil heat exchanger and straight tube heat exchanger are obtained and are compared. From our obtained results, the helical coil heat exchanger showed increase in the heat transfer rate, effectiveness and overall heat transfer coefficient over the straight tube heat exchanger on all mass flow rates and operating conditions. The centrifugal force due to the curvature of the tube results in the secondary flow development which enhances the heat transfer rate. Comparative study shows that helical coil heat exchanger is having better performance that straight tube heat exchanger.
EXPERIMENTAL AND THEORTICAL STUDY OF THE THERMAL PERFORMANCE OF HEAT PIPE HEA...IAEME Publication
Heat pipe heat exchanger (HPHE) considers one of the most useful devices for the recovery of waste heat energy. An Experimental study has been carried out on air to –air HPHE constructed of thermosyphon heat pipes with distilled water as the working fluid and a fill ratio of 75% from the evaporator length. Its model was composed of 4 rows, each row contains 12 copper tubes, each tube have ID= 9.5 mm, OD=10mm and length =950 mm and the rows of tubes were arranged in a staggered manner. Aluminum wavy plate fins of 0.1mm thickness were fixed among the tubes to increase the heat transfer area. Tests were conducted at various flow rates (air flow rate through evaporator and condenser sections) ranged between 0.12 and 0.37 kg/s and at different temperatures of air entering evaporator section (90, 100,110) ℃ to indicate discontinuity in the effectiveness when the flow rate ratio equal to one .
Thermodynamic Analysis of a Cascade Refrigeration System Based On Carbon Diox...IJERA Editor
Thermodynamic analysis of a cascade refrigeration system that uses carbon dioxide-ammonia (R744-R717) as refrigerant is presented in this paper to determine the optimum condensing temperature of the cascade condenser at given design parameters, to maximize the COP of the system. The design and operating parameters considered in this study include (1) condensing, sub cooling, evaporating and super heating temperatures in the ammonia (R717) high-temperature circuit, (2) temperature difference in the cascade heat exchanger, and (3) evaporating, superheating, condensing and sub cooling in the carbon dioxide (R744) low-temperature circuit. A multilinear regression analysis was employed in order to develop two useful correlations for maximum COP, and optimum condensing temperature.
Parallel flow heat exchanger is analysed with CFD tool. A comparative study of the analytical and experimental data is carried out to better understand the temperature profile, surface heat flux and heat transfer co-efficient parameters of the heat exchanger
Application of Parabolic Trough Collectorfor Reduction of Pressure Drop in Oi...IJMER
Pipelines are the least expensive and most effective method for the oil transportation.
Due to high viscosity of crude oil, the pressure drop and pumping power requirements are very high.
So it is necessary to bring down the viscosity of crude oil. Heated pipelines are used reduce the oil
viscosity by increasing the oil temperature. Electrical heating and direct flame heating are the common
method used for heating the oil pipeline. In this work, a new application of Parabolic Trough Collector
in the field of oil pipeline transport is introduced for reducing pressure drop in oil pipelines. Oil
pipeline is heated by applying concentrated solar radiation on the pipe surface using a Parabolic
Trough Collector in which the oil pipeline acts as the absorber pipe. 3-D steady state analysis is
carried out on a heated oil pipeline using commercial CFD software package ANSYS Fluent 14.5. In
this work an effort is made to investigate the effect of concentrated solar radiation for reducing
pressure drop in the oil pipeline. The results from the numerical analysis shows that the pressure drop
in oil pipeline is get reduced by heating the pipe line using concentrated solar radiation. From this
work, the application of PTC in oil pipeline transportation is justified.
Design and Development of Parallel - Counter Flow Heat ExchangerAM Publications
Objective of this review paper reviews the literatures related to the parallel and counter flow of different types of heat exchangers and modifications made to improve the performance. Various papers were reviewed from those papers what are the developments in parallel and counter flow heat exchanger are summarized. The development of any system is need because it helps to optimize, improve performance or reduce the cost of system. The heat exchanger development did by many researchers using software’s, design methods, changing the designs, changing shape of tubes, applying second law of thermodynamics etc. The fluid velocity, Reynolds number, overall heat transfer coefficient, baffle spacing, number of baffles, pressure drop, LMTD, helix angle of tubes plays very important role in heat exchanger performance.
In this Thesis I will try to understand the concept associated with cooling towers and model a laboratory sized cooling tower in a software package called Engineering Equation Solver (EES). An example of system modelling is presented in this progress report, along with the comparison of a set of results with an experimental data from P.A Hilton Model H892 Bench top cooling tower with a maximum of 9% error. A user interface is also modelled to simulate off-design performance rather than conducting experiments. It also allows you to do additional scenarios that cannot be practically being done in lab,
like Relative humidity, etc.
Effect of nanofluids and mass flow rate of air on heat transfer rate in autom...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Experimentation and analysis of heat transfer through perforated fins of diff...SharathKumar528
Engineering Project by Abhijath HB, Dashartha H S, Akshay Mohanraj and Sharath Kumar M S involving analysis of Fins( Heat exchanging extensions) with various geometrical perforations.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
EXPERIMENTAL AND THEORTICAL STUDY OF THE THERMAL PERFORMANCE OF HEAT PIPE HEA...IAEME Publication
Heat pipe heat exchanger (HPHE) considers one of the most useful devices for the recovery of waste heat energy. An Experimental study has been carried out on air to –air HPHE constructed of thermosyphon heat pipes with distilled water as the working fluid and a fill ratio of 75% from the evaporator length. Its model was composed of 4 rows, each row contains 12 copper tubes, each tube have ID= 9.5 mm, OD=10mm and length =950 mm and the rows of tubes were arranged in a staggered manner. Aluminum wavy plate fins of 0.1mm thickness were fixed among the tubes to increase the heat transfer area. Tests were conducted at various flow rates (air flow rate through evaporator and condenser sections) ranged between 0.12 and 0.37 kg/s and at different temperatures of air entering evaporator section (90, 100,110) ℃ to indicate discontinuity in the effectiveness when the flow rate ratio equal to one .
Thermodynamic Analysis of a Cascade Refrigeration System Based On Carbon Diox...IJERA Editor
Thermodynamic analysis of a cascade refrigeration system that uses carbon dioxide-ammonia (R744-R717) as refrigerant is presented in this paper to determine the optimum condensing temperature of the cascade condenser at given design parameters, to maximize the COP of the system. The design and operating parameters considered in this study include (1) condensing, sub cooling, evaporating and super heating temperatures in the ammonia (R717) high-temperature circuit, (2) temperature difference in the cascade heat exchanger, and (3) evaporating, superheating, condensing and sub cooling in the carbon dioxide (R744) low-temperature circuit. A multilinear regression analysis was employed in order to develop two useful correlations for maximum COP, and optimum condensing temperature.
Parallel flow heat exchanger is analysed with CFD tool. A comparative study of the analytical and experimental data is carried out to better understand the temperature profile, surface heat flux and heat transfer co-efficient parameters of the heat exchanger
Application of Parabolic Trough Collectorfor Reduction of Pressure Drop in Oi...IJMER
Pipelines are the least expensive and most effective method for the oil transportation.
Due to high viscosity of crude oil, the pressure drop and pumping power requirements are very high.
So it is necessary to bring down the viscosity of crude oil. Heated pipelines are used reduce the oil
viscosity by increasing the oil temperature. Electrical heating and direct flame heating are the common
method used for heating the oil pipeline. In this work, a new application of Parabolic Trough Collector
in the field of oil pipeline transport is introduced for reducing pressure drop in oil pipelines. Oil
pipeline is heated by applying concentrated solar radiation on the pipe surface using a Parabolic
Trough Collector in which the oil pipeline acts as the absorber pipe. 3-D steady state analysis is
carried out on a heated oil pipeline using commercial CFD software package ANSYS Fluent 14.5. In
this work an effort is made to investigate the effect of concentrated solar radiation for reducing
pressure drop in the oil pipeline. The results from the numerical analysis shows that the pressure drop
in oil pipeline is get reduced by heating the pipe line using concentrated solar radiation. From this
work, the application of PTC in oil pipeline transportation is justified.
Design and Development of Parallel - Counter Flow Heat ExchangerAM Publications
Objective of this review paper reviews the literatures related to the parallel and counter flow of different types of heat exchangers and modifications made to improve the performance. Various papers were reviewed from those papers what are the developments in parallel and counter flow heat exchanger are summarized. The development of any system is need because it helps to optimize, improve performance or reduce the cost of system. The heat exchanger development did by many researchers using software’s, design methods, changing the designs, changing shape of tubes, applying second law of thermodynamics etc. The fluid velocity, Reynolds number, overall heat transfer coefficient, baffle spacing, number of baffles, pressure drop, LMTD, helix angle of tubes plays very important role in heat exchanger performance.
In this Thesis I will try to understand the concept associated with cooling towers and model a laboratory sized cooling tower in a software package called Engineering Equation Solver (EES). An example of system modelling is presented in this progress report, along with the comparison of a set of results with an experimental data from P.A Hilton Model H892 Bench top cooling tower with a maximum of 9% error. A user interface is also modelled to simulate off-design performance rather than conducting experiments. It also allows you to do additional scenarios that cannot be practically being done in lab,
like Relative humidity, etc.
Effect of nanofluids and mass flow rate of air on heat transfer rate in autom...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Experimentation and analysis of heat transfer through perforated fins of diff...SharathKumar528
Engineering Project by Abhijath HB, Dashartha H S, Akshay Mohanraj and Sharath Kumar M S involving analysis of Fins( Heat exchanging extensions) with various geometrical perforations.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
PARAMETRIC INVESTIGATIONS ON THE FLOW CHARACTERISTICS OF A CLOSED LOOP PULSAT...IAEME Publication
Pulsating Heat Pipe (PHP) is two phase passive heat transfer device for low temperature applications. Even though it is a simple, flexible and cheap structure, its complex physics has not been fully understood and requires a robust, validated simulation tool. In the present work the basic theoretical model by H.B. Ma et al has been updated with the inclusion of capillary effect in order to characterise the pulsating flow for various refrigerants which could be used in PHPs. The mathematical model is solved using explicit embedded Range-kutta method and the slug displacement and velocity are investigated under various influencing parameters.
Experimental Investigation on the Heat Transfer Coefficient of the Thermosyph...IJERA Editor
Two phase closed thermosyphon is a good heat transfer device. A large heat is transferred from evaporator to condenser with relatively a small temperature difference. In the present work, the heat transfer performance of two phase closed thermosyphon is analyzed experimentally with different cross section shape for the thermosyphon tube. A copper thermosyphon has been constructed with three different cross section shape (circular, square and rectangular) having the same hydraulic diameter and length. Methanol is used as the working fluid. The temperature distribution across the thermosyphon outer surface was measured and recorded using thermocouples. The results showed that the heat transfer coefficient increases with the increase of input power, thermal resistance is indirectly proportional to the input power. The maximum heat transfer coefficient (1815 W/m2C) for square cross section at the input power (500 W).
CFD Analysis of Heat Transfer Enhancement in Shell and Tube Type Heat Exchang...ijtsrd
Shell and Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters. Shell and Tube heat exchanger is one such heat exchanger, provides more area for heat transfer between two fluids in comparison with other type of heat exchanger. To intensify heat transfer with minimum pumping power innovative heat transfer fluids called Nano fluids have become the major area of research now a days. The primary aim is to evaluate the effect of different weight concentration and temperatures on convective heat transfer. Increasing the weight concentration and temperatures leads to enhancement of convective heat transfer coefficient. In the present, work attempts are made to enhance the heat transfer rate in shell and tube heat exchangers. A multi pass shell and tube heat exchanger with 3 tubes with fins modelling is done using ANSYS. Nanofluid such as Al2O3-H2O is used. The CFD simulated results achieved from the use of the creating fin in tube side in shell and tube type heat exchanger are compared with without fin. Based on the results, providing fins on tube causes the increment of overall heat transfer coefficient which results in the enhancement of heat transfer rate of heat exchanger. Sudhanshu Pathak | H. S. Sahu"CFD Analysis of Heat Transfer Enhancement in Shell and Tube Type Heat Exchanger creating Triangular Fin on the Tubes" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd14259.pdf http://www.ijtsrd.com/engineering/mechanical-engineering/14259/cfd-analysis-of-heat-transfer-enhancement-in-shell-and-tube-type-heat-exchanger-creating-triangular-fin-on-the-tubes/sudhanshu-pathak
Heat transfer to down flowing viscous films with Evaporation from the interfaceinventionjournals
Introduction: Within long vertical boiling tubes thermo hydrodynamic processes in liquid film take place at a regime of cycling mixing in the bulk of the film by the powerful waves. The existing Heat Transfer models of such phenomena do not take info account such intermittent mixing of fluid Materials and methods: The heat transfer and hydrodynamic processes that take place in down flowing film of water and sugar solutions at the regimes of evaporation from the interface have been studied. There were developed mathematical models, which then were compared with the result of direct experimentation of heat transfer in tubes at the regimes of solutions concentrations. Results and discussion: A mathematical model of heat transfer in laminar, heated to the saturation temperatures liquid films with the developed wavy structures on the free interface have been developed. The model takes into consideration cyclic relaxation of transient temperature field which happens right after the passage of a powerful big wave. The developed mathematical model describes the time history of the two dimensional temperature fields as a function of the Peclet number and the core characteristic of the wavy motion (the length of big waves). Based upon the proposed model a set of correlations have been obtained. These are proposed as a means for the generalization of heat transfer experimental data, obtained within the experimental studies of liquid films, heated to the saturation temperatures and evaporating from the interface. A generalized equation has been derived, which can be used for the calculations of Heat Transfer Coefficients (HTC) to the saturated sugar solutions liquid films. This equation contains wavy characteristics of down flowing films and valid within the range of parameters characteristic for the sugar industry evaporators, namely: concentrations – 0…70 % dry matter; liquid mass flow rate density–0.01×10-3…0.6×10-3 m 2 /sec, the Peclet number range – 400…25000. The mathematical model of the temperature field cyclic relaxation turned out efficient for generalization of heat transfer experimental data not only laminar, but turbulent liquid films either, despite of the fact that the transport equations do not contain turbulent characteristics. Conclusions: A correlation between the liquid film wavy structure with the heat transfer has been established. The correlation is based upon the model of temperature field cyclic relaxation after passage of big waves. The respective correlations have been presented.
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.
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.
Abstract: Heat pipe are high-efficient heat transfer devices and have been widely applied in various thermal systems. Since heat pipe utilize the phase change of the working fluid to transport the heat, the selection of working fluid is of essential importance to promote the thermal performance of heat pipe. Owing to the heat transfer enhancement effect of nanofluid in the single phase and phase change heat transfer, some researchers have applied various nanofluids in heat pipe as the working fluids to enhance their heat transfer performance.
Thermal analysis of various duct cross sections using altair hyperworks softwaresushil Choudhary
In this work thermal analysis and comparison of various duct cross sections is done computationally using Altair
Hyperworks Software. Simple Analytical results were obtained for conduction and convection through the ducts
which can be used to build up thermal circuit. The inner surface of all ducts is maintained at constant
temperature and ambient air is at certain temperature that is less than inner surface temperature of pipe. Due to
temperature difference heat will flow from higher temperature to lower temperature. Due to temperature
difference heat will flow from higher temperature to lower temperature. The material of pipe provides
conductive resistance and air provides convective resistance. Hence this is a mix mode of heat transfer. The heat
transfer takes place in one dimension only and properties are considered to be isotropic. The ducts are assumed
to be made of aluminium having known thermal conductivity and density. The surroundings of ducts have
known convective heat transfer coefficient and temperature. The results are obtained on hyperview which are for
heat flux, temperature gradient and grid temperature. The different characteristics can be obtained by varying the
material of the ducts.
NUMERICAL SIMULATION OF FORCED CONVECTION HEAT TRANSFER ENHANCEMENT BY POROUS...IAEME Publication
Pin fins have a variety of applications in industry due to their excellent heat transfer performance, e.g., in cooling of electronic components, in cooling of gas turbine blades, and
recently, in hot water boilers of central heating systems. The forced convective heat transfer in three dimensional porous pin fin channels is numerically studied using ANSYS Fluent. Geometric modelling is done using Design Modeller and CFD Meshing is carried out using ANSYS Meshing Preprocessor. The effects of Reynolds number (Re), pore density (PPI) and pin fin form are studied in detail.
HEAT TRANSFER AUGMENTATION IN A PLATE-FIN HEAT EXCHANGER: A REVIEWIAEME Publication
The improvement of the performance of heat exchangers with gas as the working fluid becomes particularly important due to the high thermal resistance offered by gases in general. In order to compensate for the poor heat transfer properties of gases, the surface area density of plate heat exchangers can be increased by making use of the secondary fins such as, off-set fins, triangular fins, wavy fins, louvered fins etc. In addition, a promising technique for the enhancement of heat transfer is the use of longitudinal vortex generators. The longitudinal vortices are produced due to the pressure difference generated between the front and back surface of the vortex generator.
CFD Analysis of a Double Pipe Heat Exchanger by using Fluid Based Nanomaterialsijtsrd
Double pipe heat exchanger design is a device which we using for heat transfer applications straightforward. This maintains one heat exchanger pipe inside another. After determining the required heat exchanger surface area, for either counter flow or parallel flow, the pipe sizes and number of bends for the double pipe heat exchanger can be selected. In double pipe heat exchanger design, an important factor is the type of flow pattern in the heat exchanger. A double pipe heat exchanger will typically be either counterblow or parallel flow. Cross flow just doesnt work for a double pipe heat exchanger. The flow pattern and the required heat exchange duty allow calculation of the log mean temperature difference. That together with an estimated overall heat transfer coefficient allows calculation of the required heat transfer surface area. Then pipe sizes, pipe lengths and number of bends can be determined. The convective heat transfer, friction factor and effectiveness of different volume concentrations of Fe3O4 Nano fluid flow in an inner tube of double pipe heat exchanger with return bend has been estimated experimentally and turbulent flow conditions. The test section used in this study is of double pipe type in which the inner tube diameter is 0.019 m, the annulus tube diameter is 0.05m and the total length of inner tube is 5 m. At a distance of 2.2mfromthe inlet of the inner tube the return bend is provided. The hot Nanofluids flows through an inner tube, whereas the cold water flows through an annulus tube. The volume concentrations of the nanoparticles used in this study are 0.03 and 8 lpm ,10 lpm mass flow rate with Reynolds number range from 9,000 to 30,000.in the process analyze the CFD analysis is performed in Ansys Fluent 15.0 workbench and its used different nanofluids used, which nanofluids better heat transfer rate find base on the results.In this process choose different nanofluids Al2o3, Cuo ,Fe3o4 this nanofluids properties taken by different base papers. Golkonda Venkata Apparao | K. Srinivasa Rao "CFD Analysis of a Double Pipe Heat Exchanger by using Fluid Based Nanomaterials" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-2 , February 2019, URL: https://www.ijtsrd.com/papers/ijtsrd20306.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/20306/cfd-analysis-of-a-double-pipe-heat-exchanger-by-using-fluid-based-nanomaterials/golkonda-venkata-apparao
Total Ionization Cross Sections due to Electron Impact of Ammonia from Thresh...Dr. Amarjeet Singh
In the present paper, we have employed modified Khare-BEB method [Atoms, (2019)] to evaluate total ionization cross sections by the electron impact for ammonia in energy range from the ionization threshold to 10 MeV. The theoretical ionization cross sections have been compared to the available previous theoretical and experimental results. The collision parameters dipole matrix squared M_j^2 and CRP also have been calculated. The present calculations were found in remarkable agreement with the available experimental results.
A Case Study on Small Town Big Player – Enjay IT Solutions Ltd., BhiladDr. Amarjeet Singh
Adequately trained Manpower is a problem that affects the IT industry as a whole, but it is particularly acute for Enjay IT Solution. Enjay's location in a semi-urban or rural area makes it even more difficult to find a talented employee with the right skills. As the competition for skilled workers grows, it becomes more difficult to attract and keep those workers who have the requisite training and experience.
Effect of Biopesticide from the Stems of Gossypium Arboreum on Pink Bollworm ...Dr. Amarjeet Singh
Pink bollworm and Lepidoptera development quickly in numbers which is a typical animal group that produces around 100 youthful ones inside certain days or weeks. This assault influences the harvests broadly in the tropical and sub-tropical temperature areas. Thus, to keep up with the yield of harvests the vermin ought to be kept away by utilizing pesticides. The unnecessary measure of the purpose of pesticides influences the dirt, land, and as well as human well-being, and contaminates the climate. Thus, an ozone-accommodating biopesticide is extracted from the stems of the Gossypium arboreum. Thus, the extraction of biopesticide from the stems of Gossypium arboreum demonstrated that the quantity of pink bollworm and Lepidoptera is diminished step by step in the wake of showering the arrangement on the impacted region of the plant because of the presence of the gossypol.
Artificial Intelligence Techniques in E-Commerce: The Possibility of Exploiti...Dr. Amarjeet Singh
E-Commerce has transformed business as we know over the past few decades. The rapid increasing use of the Internet and the strong purchasing power in Saudi Arabia have had a strong impact on the evolution of E-Commerce in the country. Saudi Arabia is yet another country that will release artificial intelligence power to fuel its growth in the economic world. Recently, artificial intelligence (AI) applications that can facilitate e-commerce processes have been widely used. The impact of using artificial intelligence (AI) concepts and techniques on the efficiency of e-commerce, particularly has been overlooked by many prior studies. In this paper, a literature review was conducted to explore and investigate possible applications of AI in E-Commerce that can help Saudi Arabian businesses.
Factors Influencing Ownership Pattern and its Impact on Corporate Performance...Dr. Amarjeet Singh
This study on factors influencing Ownership pattern and its impact on corporate performance has used five industries data viz Automobile industry, IT industry, Banking industry, Oil & Gas industry and pharmaceutical industry for five years from 2017 to 2021. First the factors influencing ownership pattern was identified and later its impact on corporate performance was analysed. Multiple Regression, ANOVA and Correlation was used in SPSS 28. Percentage of independent directors on the board and size of the company has significant impact on Indian Promotor holding and non-institutional ownership has significant impact on corporate performance.
An Analytical Study on Ratios Influencing Profitability of Selected Indian Au...Dr. Amarjeet Singh
Every country with a well-developed transportation network has a well-developed economy. The automobile industry is a critical engine of the nation's economic development. The automobile industry has significant backward and forward links with every area of the economy, as well as a strong and progressive multiplier impact. The automotive industry and the auto component industry are both included in the vehicle industry. It includes passenger waggons, light, medium, and heavy commercial vehicles, as well as multi-utility vehicles such as jeeps, three-wheelers, military vehicles, motorcycles, tractors, and auto-components such as engine parts, batteries, drive transmission parts, electrical, suspension and chassis parts, and body and other parts. In the last several years, India's automobile sector has seen incredible growth in sales, production, innovation, and exports. India's car industry has emerged as one of the best in the world, and the auto-ancillary sector is poised to assist the vehicle sector's expansion. Vehicle manufacturers and auto-parts manufacturers account for a significant component of global motorised manufacturing. Vehicle manufacturers from across the world are keeping a close eye on the Indian auto sector in order to assess future demand and establish India as a global manufacturing base. The current research focuses on three automotive behemoths: TATA Motors, MRF, and Mahindra & Mahindra.
A Study on Factors Influencing the Financial Performance Analysis Selected Pr...Dr. Amarjeet Singh
The growth of a country's banking sector has a significant impact on its economic development. The banking sector plays a critical role in determining a country's economic future. A well-planned, structured, efficient, and viable banking system is an essential component of an economy's economic and social infrastructure. In modern society, a strong banking system is required because it meets the financial needs of the modern society. In a country's economy, the banking system plays a crucial role. Because it connects surplus and deficit economic agents, the bank is the most important financial intermediary in the economy. The banking system is regarded as the economy's lifeline. It meets the financial needs of commerce, industry, and agriculture. As a result, the country's development and the banking system are intertwined. They are critical in the mobilisation of savings and the distribution of credit to various sectors of the economy. India's private sector banks play a critical role in the country's economic development. So The financial performance of private sector banks must be evaluated carefully.
An Empirical Analysis of Financial Performance of Selected Oil Exploration an...Dr. Amarjeet Singh
After the United States, China, and Japan, India was the world's fourth biggest consumer of oil and petroleum products. The nation is significantly reliant on crude oil imports, the majority of which come from the Middle East. The Indian oil and gas business is one of the country's six main sectors, with important forward links to the rest of the economy. More than two-thirds of the country's overall primary energy demands are met by the oil and gas industry. The industry has played a key role in placing India on the global map. India is now the world's sixth biggest crude oil user and ninth largest crude oil importer. In addition, the country's portion of the worldwide refining market is growing. India's refining industry is now the world's sixth biggest. With plans for Reliance Petroleum Limited to commission another refinery with a capacity of 29 MTPA next 16 to its 33 MTPA refinery in Jamnagar, Gujarat, this position is projected to be enhanced. As a consequence, the Reliance refinery would be the biggest single-site refinery in the world. Based on secondary data gathered from CMIE, the current research examines the ratios influencing the profitability of selected oil exploration and production businesses in India during a 10-year period.
Since 1991, thanks to economic policy liberalization, the Indian economy has entered an era in which Indian businesses can no longer disregard global markets. Prior to the 1990s, the prices of a variety of commodities, metals, and other assets were carefully regulated. Others, which were not rolled, were primarily dependant on regulated input costs. As a result, there was no uncertainty and, as a result, no price fluctuations. However, in 1991, when the process of deregulation began, the prices of most items were deregulated. It has also resulted in the exchange being partially deregulated, easing trade restrictions, lowering interest rates, and making significant advancements in foreign institutional investors' access to the capital markets, as well as establishing market-based government securities pricing, among other things. Furthermore, portfolio and securities price volatility and instability were influenced by market-determined exchange rates and interest rates. As a result, hedging strategies employing a variety of derivatives were exposed to a variety of risks. The Indian capital market will be examined in this study, with a focus on derivatives.
Theoretical Estimation of CO2 Compression and Transport Costs for an hypothet...Dr. Amarjeet Singh
SEI S.p.a. presented a project to build a 1320 MW coal-fired power plant in Saline Joniche, on the Southern tip of Calabria Region, Italy, in 2008. A gross early evaluation about the possibility to add CCS (CO2 Capture & Storage) was performed too. The project generated widespread opposition among environmental associations, citizens and local institutions in that period, against the coal use to produce energy, as a consequence of its GHG clima-alterating impact. Moreover the CCS (also named Carbon Capture & Storage or more recently CCUS: Carbon Capture-Usage-Storage) technology was at that time still an unknown and “mysterious” solution for the GHG avoiding to the atmosphere. The present study concerns the sizing of the compression and transportation system of the CCS section, included in the project presented at the time by SEI Spa; the sizing of the compression station and the pipeline connecting the plant to the possible Fosca01 offshore injection site previously studied as a possible storage solution, as part of a coarse screening of CO2 storage sites in the Calabria Region. This study takes into account the costs of construction, operation and maintenance (O&M) of both the compression plant and the sound pipeline, considering the gross static storage capacity of the Fosca01 reservoir as a whole as previously evaluated.
Analytical Mechanics of Magnetic Particles Suspended in Magnetorheological FluidDr. Amarjeet Singh
In this paper, the behavior of MR particles has been systematically investigated within the scope of analytical mechanics. . A magnetorheological fluid belongs to a class of smart materials. In magnetorheological fluids, the motion of magnetic particles is controlled by the action of internal and external forces. This paper presents analytical mechanics for the interaction of system of particles in MR fluid. In this paper, basic principles of Analytical Mechanics are utilized for the construction of equations.
Techno-Economic Aspects of Solid Food Wastes into Bio-ManureDr. Amarjeet Singh
Solid waste is health hazard and cause damage to the environment due to improper handling. Solid waste comprises of Industrial Waste (IW), Hazardous Waste (HW), Municipal Solid Waste (MSW), Electronic waste (E-waste), Bio-Medical Waste (BMW) which depend on their supply & characteristics. Food waste or Bio-waste composting and its role in sustainable development is explained in food waste is a growing area of concern with many costs to our community in terms of waste collection, disposal and greenhouse gases. When rotting food ends up in landfill it turns into methane, a greenhouse gas that is particularly damaging to the environment. Composting is biochemical process in which organic materials are biologically degraded, resulting in the production of organic by products and energy in the form of heat. Heat is trapped within the composting mass, leading to the phenomenon of self-heating. This overall process provide us Bio-Manure.
Crypto-Currencies: Can Investors Rely on them as Investment Avenue?Dr. Amarjeet Singh
The purpose of this study is to examine investors’ perceptions about investing in crypto-currencies. We think that investors trust in crypto-currencies is largely driven by crypto-currency comprehension, trust in government, and transaction speed. This is the first study to examine crypto-currencies from the investor’s perspective. Following that, we discover important antecedents of crypto-currency confidence. Second, we look at the government's role in crypto-currencies. The importance of this study is: first, crypto-currencies have the potential to disrupt the current economic system as the debate is all about impact of decentralization of transactions; thus, further research into how it affects investors trust is essential; and second, access to crypto-currencies. Finally, if Fin-Tech companies or banks want to enter the bitcoin industry may not attract huge advertising costs as well as marketing to soothe clients' concerns about investing in various digital currencies The research sheds light on indecisiveness in the context of marketing aspects adopted by demonstrating investors are aware about the crypto.
Awareness of Disaster Risk Reduction (DRR) among Student of the Catanduanes S...Dr. Amarjeet Singh
The Island Province of Catanduanes is prone to all types of natural hazards that includes torrential and heavy rains, strong winds and surge, flooding and landslide or slope failures as a result of its geographical location and topography. RA 10121 mandates local DRRM bodies to “encourage community, specifically the youth, participation in disaster risk reduction and management activities, such as organizing quick response groups, particularly in identified disaster-prone areas, as well as the inclusion of disaster risk reduction and management programs as part of youth programs and projects. The study aims to determine the awareness to disaster of the student of the Catanduanes State University. The disaster-based questionnaire was prepared and distributed among 636 students selected randomly from different Colleges and Laboratory Schools in the University
The Catanduanes State University students understood some disaster-related concepts and ideas, but uncertain on issues on preparedness, adaptation, and awareness on the risks inflicted by these natural hazards. Low perception on disaster risks are evidently observed among students. The responses of the students could be based on the efficiency and impact of the integration of DRR education in the senior high school curriculum. Specifically, integration of the concepts about the hazards, hazard maps, disaster preparedness, awareness, mitigation, prevention, adaptation, and resiliency in the science curriculum possibly affect the knowledge and understanding of students on DRR. Preparedness drills and other forms of capacity building must be done to improve awareness of the student towards DRRM.
The study further recommends that teachers and instructor must also be capacitated in handling disaster as they are the prime movers in the implementation of the DRRM in education. Preparedness drills and other forms of capacity building must be done to improve awareness of the student towards DRRM. Core subjects in Earth Sciences must be reinforced with geologic hazards. Learning competencies must also be focused on hazard identification and mapping, and coping with different geologic disaster.
The 1857 war was a watershed moment in the history of the Indian subcontinent. The battle has sparked academic debate among historians and sociologists all around the world. Despite the fact that it has been more than 150 years, this battle continues to pique the interest of historians. The war's causes and events that occurred throughout the conflict, persons who backed the British and anti-British fighters, and the results and ramifications, are all aspects of this conflict. In terms of outcomes, many academics believe that the war was a failure for those who started it. It is often assumed that the Indians who battled the British in this conflict were unable to achieve their goals. Many gains accrued to Indians as a result of the conflict, but these achievements are overshadowed by the dispute over the war's failure. This research effort focuses on the war's achievements for India, and the significance of those achievements.
Haryana's Honour Killings: A Social and Legal Point of ViewDr. Amarjeet Singh
Life is unpredictably unpredictable. Nobody knows what will happen in the next minute of their lives. In this circumstance, every human being has the right and desire to conduct their lives according to their own desires. No one should be forced to live a life solely for the benefit and reputation of others. Honour killing is defined as the assassination of a person, whether male or female, who refuses to accept the family's arranged marriage or decides to move her or his marital life according to her or his wishes solely because it jeopardizes the family's honour. The family's supreme authority looks after the family's name but neglects to consider the love and affection shared among family members. I have discussed honour killing in India in my research work. This sort of murder occurs as a result of particular triggers, which are also examined in relation to the role of the law in honour killing. No one can be released free if they break the law, and in this case, it is a felony that violates various regulations designed to safeguard citizens. This crime is similar to many others, but it is distinct enough to be differentiated in the report. When the husband is of low social standing, it lowers the position and caste of the female family, prompting the male family members to murder the girl. But they forget that the girl is their kid and that while rank may be attained, a girl's life can never be replaced, and that caste is less valuable than the girl's life and love spent with them.
Optimization of Digital-Based MSME E-Commerce: Challenges and Opportunities i...Dr. Amarjeet Singh
The impact caused by the Covid-19 Pandemic on Micro and Small and Medium Enterprises (MSMEs) was so severe and fatal
that not a few went out of business. The heavy burden is borne by MSME actors due to social restrictions imposed by the
government, the declining purchasing power of the people, a product that continues to decline until capital runs out. Plus
inadequate knowledge in carrying out marketing strategies and product innovations are the main trigger for the lack of
enthusiasm for MSME actors as well as bankruptcy. MSME digitalization-based e-commerce is an opportunity and the right
solution in dealing with the obstacles caused by the impact of Covid-19, as well as a challenge for MSME actors to design old
ways in new ways through digital business.
Modal Space Controller for Hydraulically Driven Six Degree of Freedom Paralle...Dr. Amarjeet Singh
This paper presents the Modal space decoupled control for a hydraulically driven parallel mechanism has been presented. The approach is based on singular values decomposition to the properties of joint-space inverse mass matrix, and mapping of the control and feedback variables from the joint space to the decoupling modal space. The method transformed highly coupled six-input six-output dynamics into six independent single-input single-output (SISO) 1 DOF hydraulically driven mechanical systems. The novelty in this method is that the signals including control errors, control outputs and pressure feedbacks are transformed into decoupled modal space and also the proportional gains and dynamic pressure feedback are tuned in modal space. The results indicate that the conventional controller can only attenuate the resonance peaks of the lower eigenfrequencies of six rigid modes properly, and the peaking points of other relative higher eigenfrequencies are over damped, The further results show that it is very effective to design and tune the system in modal space and that the bandwidth increased substantially except surge (x) and sway (y) motions, each degree of freedom can be almost tuned independently and their bandwidths can be increased near to the undamped eigenfrequencies.
It is a known fact that a large number of Steel Industry Expansion projects in India have been delayed due to regulatory clearances, environmental issues and problems pertaining to land acquisition. Also, there are challenges in the tendering phase that affect viability of projects thus delaying implementation, construction phase is beset with over-runs and disputes and last but not the least; provider skills are weak all across the value chain. Given the critical role of Steel Sector in ensuring a sustained growth trajectory for India, it is imperative that we identify the core issues affecting completion of infrastructure projects in India and chalk out initiatives that need to be acted upon in short term as well as long term.
A blockchain is a decentralised database that is shared across computer network nodes. A blockchain acts as a database, storing information in a digital format. The study primarily aims to explore how in the future, block chain technology will alter several areas of the Indian economy. The current study aims to obtain a deeper understanding of blockchain technology's idea and implementation in India, as well as the technology's potential as a disruptive financial technological innovation.
Secondary sources such as reports, journals, papers, and websites were used to compile all the data. Current and relevant information were utilised to help understand the research goals. All the information is rationally organised to fulfil the objectives. The current research focuses on recommendations for enhancing India's Blockchain ecosystem so that it may become one of the best in the world at utilising this new technology.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
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Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
Numerical Simulation of Helically Coiled Closed Loop Pulsating Heat Pipe
1. International Journal of Engineering and Management Research e-ISSN: 2250-0758 | p-ISSN: 2394-6962
Volume- 9, Issue- 2 (April 2019)
www.ijemr.net https://doi.org/10.31033/ijemr.9.2.26
206 This work is licensed under Creative Commons Attribution 4.0 International License.
Numerical Simulation of Helically Coiled Closed Loop Pulsating Heat Pipe
Bhagwat Adhikari1
and Dr. Sanjeev Maharjan2
1
Student, Department of Mechanical Engineering, IOE-Pulchowk Campus, NEPAL
2
Professor, Department of Mechanical Engineering, IOE-Pulchowk Campus, NEPAL
1
Corresponding Author: adh.bhagwat@gmail.com
ABSTRACT
This paper addresses the numerical simulation of
helically coiled closed loop pulsating heat pipe which is carried
in ANSYS Fluent. The values of thermal resistance for
constant heat fluxes vs. transient heat fluxes are analyzed.
Phase change visualization after the end of simulation is
carried out to observe the phenomenon in liquid at its
saturation temperature and pressure. Finally, helical heat
pipes are found to have thermal resistance less by 2.7K/W,
0.56 K/W, and 0.227 K/W for 8W, 40W and 80W heat inputs
than circular pipes. Helical heat pipes are found more efficient
than circular heat pipes.
Keywords— Helical, pulsating heat pipe, simulation,
thermal resistance
Table 1: List of Abbreviations
Abbreviations
Q Heat
Te Evaporator temperature
Tc Condenser temperature
R Thermal resistance
p pressure
Nu Nusselt number
Pr Prandtl number
Re Reynold's Number
S Source Term
Coeff. coefficient to be tuned
v vapor
V Velocity
T Temperature
hs condensation heat transfer coefficient
x vapor quality
Cp,w effective heat capacity of wall
kw thermal conductivity of wall
I. INTRODUCTION
An efficient heat transfer technology the subject of
research globally. The amount of fossil fuels from the earth
crust has been declining and is towards extinction. In
addition to this, the global warming caused by the use of
fossil fuels has compelled the researchers to find an
alternative solution which can address the problem. In the
area of automobile, an alternative to combustion engine can
be high voltage battery which could deliver the same
amount of power and torque. Similarly, the electric
generation via use of coal may be possibly replaced by the
use of solar energy to produce electricity. The storage and
effective transfer of thermal energy system is thought to be
crucial in near future.
Heat pipes are recognized as one of the most
efficient passive heat transfer technologies available. A heat
pipe is a structure with very high thermal conductivity that
enables the transportation of heat whilst maintaining almost
uniform temperature along its heated and cooled sections.
In general, heat pipes are passive thermal transfer devices
able to transport large amounts of heat over relatively long
distances, with no moving parts, using phase-change
processes and vapor diffusion. The main structure of a heat
pipe consists of an evacuated tube partially filled with a
working fluid that exists in both liquid and vapor phases.
The application of the heat pipes is widely known.
The high voltage battery in hybrid-electric, electric vehicles
is said to have maximum efficiency at the temperature of 35
0
C. In order to maintain this temperature, the heat generated
from the battery has to be dissipated to the surrounding
which needs an efficient heat transfer medium. Heat pipes
are being experimented in this field to solve the issue. Also,
in order to transfer the solar thermal energy the people
working in the area of cryogenics fluid is trying to build the
heat pipe system. Industries are challenging the heat
transfer community to provide solutions to enable systems
that can run reliably at extremely cold temperatures.
Theoretically, a heat pipe can operate at any given
temperature, as long as the operation temperature is
between the triple and the critical points of the working
fluid utilized.
The use of heat pipe technology in heat exchange
and thermal management is expanding fast due to their
advantageous characteristics compared with conventional
heat exchangers and temperature control systems. Advances
in the design and capabilities of heat pipes have led to the
development of cost-effective manufacturing techniques for
both wicked and wickless heat pipes and this, in turn, is
2. International Journal of Engineering and Management Research e-ISSN: 2250-0758 | p-ISSN: 2394-6962
Volume- 9, Issue- 2 (April 2019)
www.ijemr.net https://doi.org/10.31033/ijemr.9.2.26
207 This work is licensed under Creative Commons Attribution 4.0 International License.
creating new areas of implementation for heat pipe based
systems. In addition, with advances in automation and
development in material sciences, new heat pipe materials
has to be investigated to deal with challenging areas that
have so far been out of reach for conventional solutions,
particularly in dealing with high temperature and strongly
contaminated flows. The addition of heat pipes in a range of
temperature scales and applications are a clear indication of
the potential for such a technology, but there are significant
modeling issues which are hindering the performance. The
lack of advancements within commercial models will result
in the increase of bespoke codes created in open source
software. The use of nano fluids can be considered
important for the future of heat pipes, but the validity of
such claims is questionable with the lack of validation.
Extensive research still needs to be conducted on
Newtonian fluids before progression onto other fluids.
The search for cost effective, reliable and efficient
thermal management system is constantly growing.
Likewise, research works trying to establish PHP as a novel
device to manage the heat flux problem in wider range of
application has attracted many scientists. PHP is seen as
potential heat controlling devices in the field of
microprocessors, solar panel, fuel cells, space exploration
and many more. Once the operational features of PHP are
fully established, PHP is certain to get a commercial
platform
Theoretical and Numerical Modeling of PHP
Assumptions
In order to model heat transfer and flow
characteristics in the theoretical model, the following
assumptions are made:
The vapor quality in the evaporator and condenser
is in linear variation along the flow direction, and
no variation in adiabatic section.
The liquid is incompressible and the vapor is
assumed to behave as an ideal gas, both in the
saturated state for ammonia working fluid during
experiment temperature area.
The heat losses causing by the convection and
radiation heat transfer between the ambient to the
tube wall of whole PHP are neglected
Governing Equations
Lee Model
The Lee model is used with the mixture and VOF
multiphase models. In the Lee model, the liquid-vapor mass
transfer (evaporation and condensation) is governed by the
vapor transport equation:
𝜕(𝛼 𝑣 𝜌 𝑣)
𝜕𝑥
+ 𝛻 ∙ 𝛼 𝑣 𝜌 𝑣 𝑉𝑣 = 𝑚𝑙𝑣 − 𝑚 𝑣𝑙
If Tl>Tsat (evaporation):
𝑚𝑙𝑣 = 𝑐𝑜𝑒𝑓𝑓 ∗ 𝛼𝑙 𝜌𝑙(𝑇𝑙 − 𝑇𝑠𝑎𝑡 )/𝑇𝑠𝑎𝑡
If Tl<Tsat (condensation):
𝑚 𝑣𝑙 = 𝑐𝑜𝑒𝑓𝑓 ∗ 𝛼 𝑣 𝜌 𝑣(𝑇𝑠𝑎𝑡 − 𝑇𝑣)/𝑇𝑠𝑎𝑡
Where,
𝛼 𝑣 = vapor volume fraction
𝛼𝑙 = liquid volume fraction
𝜌 𝑣 = vapor density
𝑉𝑣 = vapor phase velocity
𝑚𝑙𝑣,𝑚 𝑣𝑙 = the rates of mass transfer due to evaporation and
condensation
Coeff. = coefficients to be tuned which is termed as
evaporation and condensation frequency
Volume Fraction Equation
The tracking of the interface(s) between the phases
is accomplished by the solution of a continuity equation for
the volume fraction of one (or more) of the phases. For the
„w‟ phase, this equation has the following form:
1
𝜌
𝜕
𝜕𝑡
𝛼𝑙 𝜌𝑙 + 𝛻 ∙ 𝛼𝑙 𝜌𝑙 𝑣𝑙 = 𝑆 𝛼 𝑙
+ 𝑚 𝑣𝑙 − 𝑚𝑙𝑣
𝑛
𝑣=1
where, 𝑚 𝑣𝑙is the mass transfer from phase „v‟ to
phase „l‟ and 𝑚𝑙𝑣 is the mass transfer from phase „l‟ to
phase „v‟. By default „S‟, the source term on the right-hand
side of above equation is zero
The volume fraction equation will not be solved
for the primary phase; the primary-phase volume fraction
will be computed based on the following constraint:
𝛼𝑙 = 1
𝑛
𝑙=1
Condensation
The value of condensation heat transfer is
determined by the two factors, which are condensation heat
transfer coefficient hs and vapor quality x. While hs has a
direct relationship with the velocity of fluid flow in the
condenser, and the quality x relates the distribution of liquid
and vapor phase. Obviously, these two items are all varied
as the flow patterns change.
One of the most widely used has been the shah‟s
correlation, covering three flow regimes, such as the
If the flow pattern is in „„Slug Flow”, the vapor will flow
through the condenser section slowly, and the mechanism
of condensation is used following heat transfer equation,
𝑠 = 1.32 ∙ 𝑅𝑒 𝐿𝑆
−1/3
𝜌𝑙 𝜌𝑒 − 𝜌 𝑔 ∙ 𝑔 ∙ 𝑠𝑖𝑛𝛽 ∙ 𝑘𝑙
3
𝜇𝑙
2
1/3
where, ReLS is Reynolds number assuming liquid
phase flowing in tube alone.
Above figure shows a schematic of annular flow
pattern features at high input power in PHP tubes.
If the flow pattern is in „„Annular Flow”, the vapor
flowing velocity increases, and the vapor bubble becomes
long and long, the condensation heat transfer coefficient
also grows. In this case, the mechanism of condensation is
used with annular flow correlation,
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𝑁𝑢 = 0.023𝑅𝑒𝑙𝑠
0.8
𝑃𝑟𝑙
0.4
[ 1 − 𝑥 0.8
+ 3.8𝑥0.76
1 − 𝑥 0.04
/𝑃𝑟0.38
]
Where, the „Pr‟ is the reduced pressure of vapor in the
entrance of condenser.
Characteristics of Helical Coil
Inner diameter of pipe is 2r and the coil diameter is
2Rc (measured between the centers of pipes) .Dean number
is used to characterize the flow in helical pipe as same to
Reynolds number for flowing pipes. Dean number (De):
𝐷𝑒 = 𝑅𝑒
𝑟
𝑅 𝑐
where Re is the Reynolds number.
Mathematical Model
Figure 1: Schematic diagram of helical oscillating heat pipe
Same as circular pulsating heat pipe HOHP
consists of three parts: the evaporator section (Le), the
adiabatic section (La) and the condenser section (Lc), with
the coil radius ra, the pitch ps, the radius a (defined by the
increase in elevation per revolution of coils hg= 2ps, the
curvature ratio and the torsion , which can be calculated
using
𝑘 =
𝑟𝑎
2
𝑟𝑎
2 + 𝑝𝑠
2
𝜏 =
𝑝𝑠
2
𝑟𝑎
2 + 𝑝𝑠
2
Figure shows an orthogonal helical coordinate
system. The basic governing equations for helical tubes can
be represented in an orthogonal helical coordinate system,
as suggested by Germano (1982). An orthogonal helical
coordinate system can be introduced with respect to a
master Cartesian coordinate system (x, y, z), by using the
helical coordinates s for the axial direction, r for the radial
direction and for the circumferential direction.
Figure 2: Cylindrical coordinate system for heat pipe
The vector in the orthogonal coordinate system of
a HOHP isR(s), as calculated by
𝑅(𝑠) = 𝑎𝑐𝑜𝑠 𝑠 𝑖 + 𝑎 𝑠𝑖𝑛 𝑠 𝑗 + 𝑏 𝑠 𝑘
The position of any given point p inside the helical pipe can
be described by the vector X, which can be calculated as
𝑋 = 𝑅 𝑠 − 𝑟𝑠𝑖𝑛 𝜃 − 𝜏𝑠 𝑁𝑠 + 𝑟 𝑐𝑜𝑠 𝜃 − 𝜏𝑠 𝐵𝑠
Where T, N, B are the tangential, normal and bi-normal
directions to the generic curve of the pipe axis R(s) at the
point of consideration, respectively. The metric of the
orthogonal helical coordinate system is given by:
𝑑𝑥 ∙ 𝑑𝑥 = (1 + 𝑘𝑟𝑠𝑖𝑛 𝜃 − 𝜏𝑠 )2
𝑑𝑠2
+ 𝑑𝑟2
+ 𝑟2
𝑑𝜃2
where dr, ds and d are the infinitesimal increments in the
radial, axial and circumferential directions, respectively.
With this metric, one obtains the scale factor hs as given by
𝑠 = 1 + 𝑘𝑟𝑠𝑖𝑛 𝜃 − 𝜏𝑠
Governing Equations
Governing equations for the calculated of the
HOHP are the governing equation at the pipe wall and the
vapor core. In addition, there is the governing equation for
calculation of the heat transfer. All of which can be
describe as in the following.
Heat Conduction of the Pipe Wall
Under normal operation, the heat applied to the
evaporator section by an external source is conducted
through the pipe wall. The three-dimensional transient
condition heat conduction equation that describes the
temperature in the heat pipe wall from conservation of
energy is
𝜌 𝑤 𝐶𝑝,𝑤
𝛿𝑇𝑤
𝛿𝑡
=
𝑘 𝑤
𝑟
𝛿
𝛿𝑟
𝑟
𝛿𝑇𝑤
𝛿𝑟
+
𝑘 𝑤
𝑟
𝛿2
𝑇𝑤
𝛿𝜃2
+ 𝑘 𝑤
𝛿2
𝑇𝑤
𝛿𝑧2
+ 𝑄 𝑤
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where Cp,w is the effective heat capacity of the pipe wall,
and kw is the effective thermal conductivity of the pipe wall.
Vapor Core
The continuity, the momentum and the energy
equations used in the calculation at the vapor core of the
HOHP are given
Continuity Equation:
𝜕𝑟𝑤
𝜕𝑠
= 0
Momentum Equation
𝜕𝑤
𝜕𝑡
+
1
𝑠
𝜕𝑤
𝜕𝑠
+
𝑘𝑠𝑖𝑛(𝜃 − 𝜏𝑠)
𝑠
𝑤 +
𝑘𝑐𝑜𝑠(𝜃 − 𝜏𝑠)
𝑠
𝑤
= −
1
𝑠
𝜕𝑝
𝜕𝑠
+
1
𝑅𝑒
1
𝑠
𝜕
𝜕𝑠
1
𝑟 𝑠
𝜕𝑟𝑤
𝜕𝑠
Energy Equation
𝜕𝑇
𝜕𝑡
+
𝑤
𝑠
𝜕𝑇
𝜕𝑠
=
1
𝑅𝑒𝑃𝑟
1
𝑠 𝑟
𝜕
𝜕𝑠
𝑟
𝑠
𝜕𝑇
𝜕𝑠
II. METHODOLOGY
Geometry
. Since the simulation is expensive in terms of
computation, the number of turns is taken as four. The
geometry for the figure shown above is taken from the
experimental work performed by Pachghare (2014) in order
to valid and verify the results before proceeding with the
helical structure because much researches has not been
done in the area of helical oscillating heat pipe.
Figure 3: Schematic of model for simulation
Table 2: Design parameters for helical heat pipe
Length of Evaporator 100mm
Length of Condenser 100mm
Number of turns 2.5
Diameter of coil 80mm
Diameter of pipe 2mm
Pitch 40mm
Physics Setup
On the basis of the experiment performed by
Pachghare, et al. (2014) following simulating criteria is
selected.
Table 3: Physics setup
SN Domain/Boundary/Physics Type
1 Fluid Model Volume of Fluid
(Lee Model)
2 Time step for Transient
Analysis
0.0003
3 Materials: Water Liquid & Vapor
4 Evaporation and
Condensation Model
For phase change
5 Saturation Temp & Pressure 308K & 4kPa
6 Convergence Criteria 10^-3
7 Solver: Solution Method SIMPLE
8 Wall material Copper
Boundary Conditions
First simulation is tested with 80W heat input on
the evaporator in which the heat fluxes are provided
directly to the walls of evaporator. This is the Neumann
boundary condition because it involves the value obtained
from the derivate of thermal energy per unit area with
respect to time. In some of the experiments performed by
researchers (Yeboaha et. al (2018)), the walls of evaporator
is heated by a hollow cylindrical pipe in which a hot liquid
flows.
The temperature in condenser should be less than
the saturation temperature; otherwise, the phase change
won‟t occur there. Thus condenser of the heat pipe is
maintained at 302 degree Kelvin.
Zero heat flux is assigned to the adiabatic section because
Fluent recognizes the insulation area with this value.
Copper, whose thickness is taken as 0.5mm, is
selected as wall material as it is preferred as solid material
for heat pipes due to its high thermal conductivity.
Solution Controls
The Courant number is adaptive and was not fixed
for the simulation to run. The under relaxation factors for
momentum and pressure were take as 0.3 each because
solution converged soon as this value was decreased from
the default value of 0.7.
Initial Conditions
The saturation temperature is taken to be 35 degree
Celsius for simulation. All velocities are taken zero because
at t=0, both fluids (air and water) are stationary enclosed in
closed loop. As the thermal energy is transferred slowly,
kinetic energy of the fluid particles increase and velocity is
observed. Vapor particles are expected to move from
evaporator to condenser, which is kept at a constant
temperature of 29 0
C, and condensate at 35 degree Celsius
(308 K).
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III. RESULTS AND DISCUSSIONS
Tuning of coefficients in Lee Model
The coefficients in the Lee Model has to be tuned
which is the case of hit and trial to verify the case as similar
to heat pipe. Therefore, before proceeding to the simulation
in heat pipe, a simple case was studied in a cube which has
the following case.
In a closed cubical cylinder 25% of the volume is
occupied by saturated water of mass (ml) 1.4kg and rest by
saturated steam at 200 deg Celsius. When “Q” amount of
heat to be supplied to water the water should evaporate
completely within 12.88sec.
Calculation of Q and Tuning of Lee Coeffients
Using iterative method for Lee coefficient we
obtain [Source of Lee] value of 0.0008. The Lee coefficient
signifies that the mass of water of 1.4 kg at saturation
temperature of 200C completely converts to vapor phase
with addition of Q = 3.9 MW in 14.9 sec.
Figure 4: Steam volume fraction at t=0
Figure 5: Steam volume fraction at t=14.89
Figure 6: Steam Volume fraction at t=14.9
Different to the circular structure, the thermal
resistance curve in helical first increases to the certain
amount of heat input and decreases. It is not the area of
interest beyond the value greater than 90W because heat
pipe is not suitable to transport this amount of heat from
evaporator to condenser that can result in dry out condition.
Effect of Transient Evaporator Heat Flux in Helical Pipe
In helical OHP, at a certain point in evaporator the
value of different parameters such as thermal resistance,
heat flux, steam volume fraction, difference in thermal
potentials are observed. At t= 0.5, thermal resistance is
found to be 0.54. As the rate of heat input from the
evaporator increase, thermal resistance decreases until a
constant value of 0.3 K/W is reached. At this stage the heat
flux in the evaporator is 20252 W/m2
. After increasing the
heat flux to a amount of 25390 W/m2
, the thermal
resistance value increases drastically to 0.7 K/W. The
increase in thermal resistance in that spot is due to the
formation of vapor near to that region which pushes the
liquid slug. The thermal energy in vapor phase is more than
in liquid phase which heats up the wall of the evaporator.
Hence, at this time, the circulation of the fluid commences
resulting in the flow of liquid and vapor periodically in a
particular region. The time of start of the circulation was
found to be 2.52s from the simulation result. As the time
elapses, the thermal resistance value at the particular region
in evaporator shows the same behavior as in previous time
period.
Table 4: Different thermal parameters value obtained from
simulation
t(s) Qin(Watt) Te(K) Tc(K) R
0.5 12.2401452 308.6 302 0.53920929
1.02 24.4802904 310.067 302 0.329530405
1.5 36.000357 312 302 0.277775023
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2.01 48.2405022 316.969 302 0.310299423
2.52 60.4806474 344.79 302 0.70749904
3 72.000714 330.433 302 0.394898862
3.5 84.2408592 338.336 302 0.431334632
4 96.4810044 350.411 302 0.501767164
4.2543 102.10443 357.972 302 0.548183855
Figure 7: Thermal Resistance vs. Time
Figure 8: Evaporator Temperature vs. Time
Figure 9: Thermal Resistance vs. Heat Input
The temperature of evaporator at a particular
region increases linearly at first because the wall heats up
taking the sensible heat flux at first and increases drastically
due to the energy of the vapor phase formed by taking
evaporative heat.
Start Up Performance of Helical Heat Pipe
After heat is supplied to the evaporator, the vapor
generation starts as the saturation temperature is reached.
Due to the uniform heat flux in the evaporator, the vapor
generation starts everywhere downside and upside of the
curve. Due to gravity, the vapor bubbles from the upper part
descend to the lower region where it coalesce with the
bubbles formed in the lower region resulting in the
formation of liquid and vapor slug. As this process
continues, the vapor pressure in the evaporator region rises
till it‟s sufficient to drive the liquid and slug of vapor from
evaporator to the condenser region. The amount of time
taken for one single liquid slug to move from the evaporator
to condenser region and back to evaporator is called the
start up time.
Annular Flow
Annular flows in pipes are the flows that mostly
occur in bends. The liquid and vapor slugs change the shape
of the flow from circular to the angular due to the
centrifugal force and secondary flows.
Slug Flow
Slugs of liquid and vapor are formed when the
large amount of vapors combine which are formed at
different intervals of time. When sufficient amount of heat
is supplied to the evaporator, the change in the thermal
energy to the vapor pressure energy starts the circulation of
these slugs against the buoyant and surface tension forces.
Bubble Flow
The formation of bubble is seen at the initial stage
of heating of the heat pipe. Some amount of bubbles strike
the walls losing its kinetic energy; some starts growing in
diameter due to coalesce of the vapors.
Stratified Flow
The flow in which the bubbles and slugs in
conjunction is known as stratified flow.
The enhancement in heat transfer in helical pipe is
due to the complex flow pattern existing inside the pipe.
The helix angle and the pitch of the coil results in the
torsion of the fluid and the curvature of the coil determines
the centrifugal force. The centrifugal force develops a
secondary flow inside the helical tube. The curvature effect
makes the fluid in the outer side of the pipe to move faster
than that present inside, which gives a difference in velocity
setting up a secondary flow which changes correspondingly
with the Dean number of the flow.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 1 2 3 4 5
ThermalResistance
Time
300
310
320
330
340
350
360
370
0 2 4 6
EvaporatorTemperature
Time
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 20 40 60 80 100 120
ThermalResistance
Heat input
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Figure 10: Steam volume fraction at t=4.25 for transient
heat input with different bubbles and slugs shown
IV. CONCLUSION
From the simulation of the cubical cylinder, the
evaporation frequency to carry out this simulation was
found to be 0.0008 which is the case of hit and trial to
validate the result. This frequency, which is also termed as
coefficient, is used in the entire simulation to see
evaporation and circulation process in the heat pipe.
Thermal resistance of the heat pipe decreases from
the value gradually as heat input in the evaporator is
increased whereas, in helical pipe thermal resistance value
decreases at first and increases again decreases; thermal
resistance value in helical pipe is oscillating in nature for
different heat inputs.
Thermal resistance in helical heat pipe is less than
in circular pipe which is found from constant heat input flux
for both the geometry. From the simulation, helical
structure is found as more effective heat transfer device
compared to circular.
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