In this study, forced convection heat transfer of nanoliquids is done using both single-phase and mixture-phase models and the results are compared with experimental results. The governing equations of the study here are discretized using the finite volume method. Hybrid differencing scheme is used to calculate the face values of the control volumes. A code is written using SIMPLER algorithm and then solved using the MATLAB engine. The mixture-phase model studied here, considers two slip mechanisms between nanoparticle and base-fluid, namely Brownian diffusion and thermophoresis. Al2O3-water nanofluid is used for the study of nanofluid and the study shows significant increase in convective heat transfer coefficient while the mixturephase model demonstrates slightly lower values than the single-phase model. The study is done with various nanoparticle concentrations and Reynolds numbers. With increasing particle concentration and Reynolds number, the convective heat transfer coefficient increases and as well as the shear stress. For low concentrations of the nanoparticle, Nusselt number is slightly lower than the base fluid and as the concentration increases, the Nusselt number also rises higher than the base fluid
Magnetic field effect on mixed convection flow in a nanofluid under convectiv...IAEME Publication
An analysis is carried out to investigate the influence of the prominent magnetic effect on mixed convection heat and mass transfer in the boundary layer region of a semi-infinite vertical flat plate in a nanofluid under the convective boundary conditions. The transformed boundary layer,ordinary differential equations are solved numerically using Runge-Kutta Fourth order method.
Investigation of the Effect of Nanoparticles Mean Diameter on Turbulent Mixed...A Behzadmehr
Abstract
Turbulent mixed convection of a nanofluid (water/Al2O3, Φ=.02) has been studied numerically. Two-phase
mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. Nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. The non-uniformity of the particles distribution occurs in the case of large nanoparticles and/or high value of the Grashof numbers. The study of particle size effect showed that the effective Nusselt number and turbulent intensity increases with the decreased of particle size.
Study on Thermal and Hydrodynamic Indexes of a Nanofluid Flow in a Micro Heat...A Behzadmehr
The paper numerically presents laminar forced convection of a nanofluid flowing in a duct at microscale.
Results were compared with both analytical and experimental data and observed good concordance with
previous studies available in the literature. Influences of Brinkman and Reynolds number on thermal and
hydrodynamic indexes have been investigated. For a given nanofluid, no change in efficiency (heat dissipation
to pumping power) was observed with an increasing in Reynolds number. It was shown that the pressure was
decrease with an increase in Brinkman number. Dependency of Nu increment changes with substrate material.
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.
MHD Chemically Reacting and Radiating Nanofluid Flow over a Vertical Cone Emb...IJLT EMAS
In this study, we examine the combined effects of
thermal radiation, chemical reaction on MHD hydromagnetic
boundary layer flow over a vertical cone filled with nanofluid
saturated porous medium under variable properties. The
governing flow, heat and mass transfer equations are
transformed into ordinary differential equations using similarity
variables and are solved numerically by a Galerkin Finite
element method. Numerical results are obtained for
dimensionless velocity, temperature, nanoparticle volume
fraction, as well as the skin friction, local Nusselt and Sherwood
number for the different values of the pertinent parameters
entered into the problem. The effects of various controlling
parameters on these quantities are investigated. Pertinent
results are presented graphically and discussed quantitatively.
The present results are compared with existing results and found
to be good agreement. It is found that the temperature of the
fluid remarkably enhances with the rising values of Brownian
motion parameter (Nb).
Magnetic field effect on mixed convection flow in a nanofluid under convectiv...IAEME Publication
An analysis is carried out to investigate the influence of the prominent magnetic effect on mixed convection heat and mass transfer in the boundary layer region of a semi-infinite vertical flat plate in a nanofluid under the convective boundary conditions. The transformed boundary layer,ordinary differential equations are solved numerically using Runge-Kutta Fourth order method.
Investigation of the Effect of Nanoparticles Mean Diameter on Turbulent Mixed...A Behzadmehr
Abstract
Turbulent mixed convection of a nanofluid (water/Al2O3, Φ=.02) has been studied numerically. Two-phase
mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. Nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. The non-uniformity of the particles distribution occurs in the case of large nanoparticles and/or high value of the Grashof numbers. The study of particle size effect showed that the effective Nusselt number and turbulent intensity increases with the decreased of particle size.
Study on Thermal and Hydrodynamic Indexes of a Nanofluid Flow in a Micro Heat...A Behzadmehr
The paper numerically presents laminar forced convection of a nanofluid flowing in a duct at microscale.
Results were compared with both analytical and experimental data and observed good concordance with
previous studies available in the literature. Influences of Brinkman and Reynolds number on thermal and
hydrodynamic indexes have been investigated. For a given nanofluid, no change in efficiency (heat dissipation
to pumping power) was observed with an increasing in Reynolds number. It was shown that the pressure was
decrease with an increase in Brinkman number. Dependency of Nu increment changes with substrate material.
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.
MHD Chemically Reacting and Radiating Nanofluid Flow over a Vertical Cone Emb...IJLT EMAS
In this study, we examine the combined effects of
thermal radiation, chemical reaction on MHD hydromagnetic
boundary layer flow over a vertical cone filled with nanofluid
saturated porous medium under variable properties. The
governing flow, heat and mass transfer equations are
transformed into ordinary differential equations using similarity
variables and are solved numerically by a Galerkin Finite
element method. Numerical results are obtained for
dimensionless velocity, temperature, nanoparticle volume
fraction, as well as the skin friction, local Nusselt and Sherwood
number for the different values of the pertinent parameters
entered into the problem. The effects of various controlling
parameters on these quantities are investigated. Pertinent
results are presented graphically and discussed quantitatively.
The present results are compared with existing results and found
to be good agreement. It is found that the temperature of the
fluid remarkably enhances with the rising values of Brownian
motion parameter (Nb).
Use of Hybrid Nanofluid to Increase Heat Transfer Performance of Double Pipe ...ijtsrd
In present work, forced convection of a turbulent flow of, Al2O3 water nanofluid and Al Al2O3 water hybrid nanofluid a new advanced nanofluid composited of Al and Al2O3 nanoparticles through a double pipe heat exchanger is numerically analyzed. The solid model of the double pipe heat exchanger is created in design modular and analyzed by the computational software ANSYS 16.0.This work examines the effects of these two fluids as the working fluids, a wide range of Reynolds number 20000 = Re = 60000 and also the volume concentration 0.25 , and 0.5 on heat transfer and hydrodynamic performance. The finite volume discretization method is employed to solve the set of the governing equations. The results indicate that employing hybrid nanofluid improves the heat transfer rate with respect to nanofluid. However, the average increase of the average Nusselt number when compared to nanofluid in Al Al2O3 water hybrid nanofluid is 14 and the amount for the average increase of heat transfer coefficient would be 27.5 . Sakshi Jain | Prof. Rohit Soni "Use of Hybrid Nanofluid to Increase Heat Transfer Performance of Double Pipe Heat Exchanger using CFD" 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/ijtsrd33581.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/33581/use-of-hybrid-nanofluid-to-increase-heat-transfer-performance-of-double-pipe-heat-exchanger-using-cfd/sakshi-jain
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, 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.
Porous media has two specifications: First its dissipation area is greater than the conventional fins that enhance heat convection. Second the irregular motion of the fluid flow around the individual beads mixes the fluid more effectively. Nanofluids are mixtures of base fluid with a very small amount of nanoparticles having dimensions from 1 to 100 nm, with very high thermal conductivities, so it would be the best convection heat transfer by using porous media and nanofluids. Thus studies need to be conducted involving nanofluids in porous media. For that, the purpose of this article is to summarize the published subjects respect to the enhancement of convective heat transfer using porous media and nanofluids and identifies opportunities for future research.
Effect of pitch on heat transfer characteristics of helical coils to be used ...eSAT Journals
Abstract Maintaining temperature and eliminating loss from anaerobic reactor highly improve the production of biogas .To achieve the required temperature inside the reactor supplying hot fluid externally using helical coil heat exchanger is required. Helical coil heat exchangers are widely used in industrial applications because they are more efficient as compared to straight tube type heat exchangers. This paper deals with the effect of pitch variation on the heat transfer characteristics (convective heat transfer coefficient, Nusselt number dean number heat removal rate etc.) of helical coil heat exchangers that can be used for supplying hot fluid to maintain the temperature of the reactor to achieve high biogas production. ANSYS 14.5 was used for the numerical investigation and the present study is done for three different coils of two turns having the same cross section and coil diameter but each coil having a different pitch. Modeling of the study was carried out based on the principles of thermodynamics, fluid mechanics, heat transfer and implementing the necessary boundary conditions. The results indicate that the heat transfer enhances with increasing pitch of the helical coil but with an increased pressure drop. Keywords—Biogas, Helical coil heat exchanger, Pitch, Heat transfer characteristic
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.
Heat transfer studies were carried out in a laboratory scale gas-solid fluidized bed with 0.1m
ID x 1 m length column, using three sizes of local sand particles of 301, 454, and 560 µm. the bed
region was heated bya horizontal heat transfer probe. It was made of copper rod (15 mm ODx50 mm
long) and insulated at the ends by Teflon. A hole was drilled at the center of the rod to accommodate
a cartridge heater 200 W (6.5 mm OD x 42 mm long). Three bed inventories of sand 1.5 kg, 2.0 kg,
and 2.5 kg, four superficial air velocities of 1.0 m/s, 1.25 m/s, 1.5 m/s, 1.75 m/s were used. Three
heat fluxes of 1698.9, 2928.4, 4675.7 W m-2 were employed. The data obtained showed how the heat
transfer coefficient effected by the above operating parameters. The heat transfer coefficient is
directly proportional with air superficial velocity as well as the bed inventory and heat fluxes but
inversely proportional with sand particles size.
EXPERIMENTAL INVESTIGATION ON BOILING HEAT TRANSFER USING R134AJournal For Research
The heat transfer characteristic of R134a during boiling were experimentally investigated in a horizontal mini channels. The experiments used different parameters like saturation temperature, mass flux, vapour quality, channel diameter, channel geometry and thermo physical properties on the heat transfer coefficients. Several literatures are used to find a assessment correlations and experimental analysis to prepare an experimental setup and their results validation. Boiling heat transfer correlations and theoretical solutions are used to predict the experimental data in this research.
CFD Analysis to Analyze Thermal Characteristics of a Heat Exchanger Handling ...ijtsrd
It takes a lot of energy to have a good life. For living and working, humans nowadays rely on an abundant and constant source of power. Because energy is depleting at such a rapid rate, it has become important to use heat more efficiently, which necessitates that we preserve. As a result of the global energy crisis, many researchers have worked to improve the efficiency of thermal systems and reduce the size and thus energy consumption rates, which is one of the most critical problems due to the large and continuing increase in consumption, the increasing scarcity of energy resources, and the high cost. A 3 dimensional numerical 3 D simulation was used to evaluate the thermal properties of a heat exchanger managing a combination of dimple ribs. Handling air flow velocity through the channel was varied from 3.97 to 5.80 m s. is the subject of this study. The heat transfer physiognomies of a heat exchanger managing a combination of dimple ribs were studied using the simulation tool ANSYS 19.2. The numerical results showed that the combination of dimple ribs enhanced heat transfer significantly more than the dimple. In comparison, the average Nusselt number of a combination of dimple ribs is 4.28 percent higher than that of a channel with dimpled Plate. Abhishek Singh | Prof. Rohit Soni "CFD Analysis to Analyze Thermal Characteristics of a Heat Exchanger Handling Combination of Dimple Ribs" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-6 , October 2021, URL: https://www.ijtsrd.com/papers/ijtsrd47712.pdf Paper URL : https://www.ijtsrd.com/engineering/mechanical-engineering/47712/cfd-analysis-to-analyze-thermal-characteristics-of-a-heat-exchanger-handling-combination-of-dimple-ribs/abhishek-singh
Effect of Thermo-Diffusion and Chemical Reaction on Mixed Convective Heat And...IJERA Editor
A finite element study of combined heat and mass transfer flow through a porous medium in a circular cylindrical annulus with Soret and Dufour effects in the presence of heat sources has been analyzed. The coupled velocity, energy, and diffusion equations are solved numerically by using Galerkin- finite element technique. Shear stress, Nusslet number and Sherwood number are evaluated numerically for different values of the governing parameters under consideration and are shown in tabular form.
EFFECT OF (MGO) NANOFLUID ON HEAT TRANSFER CHARACTERISTICS FOR INTEGRAL FINNE...IAEME Publication
Experimental investigations have been carried out in this paper to study the enhancement of heat transfer characteristics for cross flow low integral finned tube heat exchanger with using of (MgO) nanofluid. The study includes designing and manufacturing of test section from Pyrex glass with dimensions (2505001200) mm width, height and length, respectively. has a single copper tube with eight passes.. The low integral finned tube with (19 mm) inner diameter, (21 mm) root diameter and (24 mm) outer diameter. The fin height is (1.5 mm), thickness (1 mm) and the pitch is (2 mm). Air was used as a cooling fluid passing across the test tube with a range of velocities (1, 2, 3 and 4) m/sec. The inner side flow rates with a range of (2, 3, 4, 5 and 6) L/min. for water and for nanofluid.
Evaluation of Shell and Tube Heat Exchanger Performance by Using ZnO/Water Na...Barhm Mohamad
To examine and investigate the impact of nanofluid on heat exchanger performance, including the total heat transfer, the effect of friction factor, the average Nusselt number, and the thermal efficiency, the output heat transfers of a shell and tube heat exchanger using ZnO nanoparticles suspended in water has been conducted numerically. The governing equations were solved using finite volume techniques and CFD simulations with ANSYS/FLUENT Solver 2021. The nanoparticles volume fractions adopted are 0.2% and 0.35% that used in numerical computations under 200 to 1400 Reynolds numbers range. The increasing of temperature is approximately 13% from the bottom to the top of heat exchanger, while the maximum enhancement of Nusselt number is about 10%, 19% for volume fractions 0.2% and 0.35% respectively. The elevated values of the friction factor at the volumetric ratios of 0.2% and 0.35% are 0.25% and 0.47% respectively. The findings demonstrate that the performance efficiency of shell and tube heat exchanger is enhanced due to the increase in Nusselt number.
Effect Of Cuo-Distilled Water Based Nanofluids On Heat Transfer Characteristi...IJERA Editor
In this paper, the heat transfer and pressure drop characteristics of the distilled water and the copper oxide-distilled water based nanofluid flowing in a horizontal circular pipe under constant heat flux condition are studied. Copper oxide nanoparticles of 40nm size are dispersed in distilled water using sodium dodecyl sulphate as surfactant and sonicated the nanofluid for three hour. Both surfactant and sonication increases the stability of the nanofluid. The nanofluids are made in three different concentration i.e. 0.1 Vol. %, 0.25 Vol. % and 0.50 Vol. %. The thermal conductivity is measured by KD2 PRO, density with pycnometer, viscosity with Brookfield LVDV-III rheometer. The results show that the thermal conductivity increases with both temperature and concentration. The viscosity and density increases with concentration but decreases with temperature. The specific heat is calculated by model and it decreases with concentration. The experimental local Nusselt number of distilled water is compared with local Nusselt number obtained by the well known shah equation for laminar flow under constant heat flux condition for validation of the experimental set up. The relative error is 4.48 % for the Reynolds number 750.9. The heat transfer coefficient increases with increase in both flow rate and concentration. It increases from 14.33 % to 46.1 % when the concentration is increased from 0.1 Vol. % to 0.5 Vol. % at 20 LPH flow rate. Friction factor decreases with increase in flow rate. It decreases 66.54 % when the flow rate increases from 10 LPH to 30 LPH for 0.1 Vol. %.
Use of Hybrid Nanofluid to Increase Heat Transfer Performance of Double Pipe ...ijtsrd
In present work, forced convection of a turbulent flow of, Al2O3 water nanofluid and Al Al2O3 water hybrid nanofluid a new advanced nanofluid composited of Al and Al2O3 nanoparticles through a double pipe heat exchanger is numerically analyzed. The solid model of the double pipe heat exchanger is created in design modular and analyzed by the computational software ANSYS 16.0.This work examines the effects of these two fluids as the working fluids, a wide range of Reynolds number 20000 = Re = 60000 and also the volume concentration 0.25 , and 0.5 on heat transfer and hydrodynamic performance. The finite volume discretization method is employed to solve the set of the governing equations. The results indicate that employing hybrid nanofluid improves the heat transfer rate with respect to nanofluid. However, the average increase of the average Nusselt number when compared to nanofluid in Al Al2O3 water hybrid nanofluid is 14 and the amount for the average increase of heat transfer coefficient would be 27.5 . Sakshi Jain | Prof. Rohit Soni "Use of Hybrid Nanofluid to Increase Heat Transfer Performance of Double Pipe Heat Exchanger using CFD" 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/ijtsrd33581.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/33581/use-of-hybrid-nanofluid-to-increase-heat-transfer-performance-of-double-pipe-heat-exchanger-using-cfd/sakshi-jain
International Journal of Mathematics and Statistics Invention (IJMSI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJMSI publishes research articles and reviews within the whole field Mathematics and Statistics, 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.
Porous media has two specifications: First its dissipation area is greater than the conventional fins that enhance heat convection. Second the irregular motion of the fluid flow around the individual beads mixes the fluid more effectively. Nanofluids are mixtures of base fluid with a very small amount of nanoparticles having dimensions from 1 to 100 nm, with very high thermal conductivities, so it would be the best convection heat transfer by using porous media and nanofluids. Thus studies need to be conducted involving nanofluids in porous media. For that, the purpose of this article is to summarize the published subjects respect to the enhancement of convective heat transfer using porous media and nanofluids and identifies opportunities for future research.
Effect of pitch on heat transfer characteristics of helical coils to be used ...eSAT Journals
Abstract Maintaining temperature and eliminating loss from anaerobic reactor highly improve the production of biogas .To achieve the required temperature inside the reactor supplying hot fluid externally using helical coil heat exchanger is required. Helical coil heat exchangers are widely used in industrial applications because they are more efficient as compared to straight tube type heat exchangers. This paper deals with the effect of pitch variation on the heat transfer characteristics (convective heat transfer coefficient, Nusselt number dean number heat removal rate etc.) of helical coil heat exchangers that can be used for supplying hot fluid to maintain the temperature of the reactor to achieve high biogas production. ANSYS 14.5 was used for the numerical investigation and the present study is done for three different coils of two turns having the same cross section and coil diameter but each coil having a different pitch. Modeling of the study was carried out based on the principles of thermodynamics, fluid mechanics, heat transfer and implementing the necessary boundary conditions. The results indicate that the heat transfer enhances with increasing pitch of the helical coil but with an increased pressure drop. Keywords—Biogas, Helical coil heat exchanger, Pitch, Heat transfer characteristic
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.
Heat transfer studies were carried out in a laboratory scale gas-solid fluidized bed with 0.1m
ID x 1 m length column, using three sizes of local sand particles of 301, 454, and 560 µm. the bed
region was heated bya horizontal heat transfer probe. It was made of copper rod (15 mm ODx50 mm
long) and insulated at the ends by Teflon. A hole was drilled at the center of the rod to accommodate
a cartridge heater 200 W (6.5 mm OD x 42 mm long). Three bed inventories of sand 1.5 kg, 2.0 kg,
and 2.5 kg, four superficial air velocities of 1.0 m/s, 1.25 m/s, 1.5 m/s, 1.75 m/s were used. Three
heat fluxes of 1698.9, 2928.4, 4675.7 W m-2 were employed. The data obtained showed how the heat
transfer coefficient effected by the above operating parameters. The heat transfer coefficient is
directly proportional with air superficial velocity as well as the bed inventory and heat fluxes but
inversely proportional with sand particles size.
EXPERIMENTAL INVESTIGATION ON BOILING HEAT TRANSFER USING R134AJournal For Research
The heat transfer characteristic of R134a during boiling were experimentally investigated in a horizontal mini channels. The experiments used different parameters like saturation temperature, mass flux, vapour quality, channel diameter, channel geometry and thermo physical properties on the heat transfer coefficients. Several literatures are used to find a assessment correlations and experimental analysis to prepare an experimental setup and their results validation. Boiling heat transfer correlations and theoretical solutions are used to predict the experimental data in this research.
CFD Analysis to Analyze Thermal Characteristics of a Heat Exchanger Handling ...ijtsrd
It takes a lot of energy to have a good life. For living and working, humans nowadays rely on an abundant and constant source of power. Because energy is depleting at such a rapid rate, it has become important to use heat more efficiently, which necessitates that we preserve. As a result of the global energy crisis, many researchers have worked to improve the efficiency of thermal systems and reduce the size and thus energy consumption rates, which is one of the most critical problems due to the large and continuing increase in consumption, the increasing scarcity of energy resources, and the high cost. A 3 dimensional numerical 3 D simulation was used to evaluate the thermal properties of a heat exchanger managing a combination of dimple ribs. Handling air flow velocity through the channel was varied from 3.97 to 5.80 m s. is the subject of this study. The heat transfer physiognomies of a heat exchanger managing a combination of dimple ribs were studied using the simulation tool ANSYS 19.2. The numerical results showed that the combination of dimple ribs enhanced heat transfer significantly more than the dimple. In comparison, the average Nusselt number of a combination of dimple ribs is 4.28 percent higher than that of a channel with dimpled Plate. Abhishek Singh | Prof. Rohit Soni "CFD Analysis to Analyze Thermal Characteristics of a Heat Exchanger Handling Combination of Dimple Ribs" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-6 , October 2021, URL: https://www.ijtsrd.com/papers/ijtsrd47712.pdf Paper URL : https://www.ijtsrd.com/engineering/mechanical-engineering/47712/cfd-analysis-to-analyze-thermal-characteristics-of-a-heat-exchanger-handling-combination-of-dimple-ribs/abhishek-singh
Effect of Thermo-Diffusion and Chemical Reaction on Mixed Convective Heat And...IJERA Editor
A finite element study of combined heat and mass transfer flow through a porous medium in a circular cylindrical annulus with Soret and Dufour effects in the presence of heat sources has been analyzed. The coupled velocity, energy, and diffusion equations are solved numerically by using Galerkin- finite element technique. Shear stress, Nusslet number and Sherwood number are evaluated numerically for different values of the governing parameters under consideration and are shown in tabular form.
EFFECT OF (MGO) NANOFLUID ON HEAT TRANSFER CHARACTERISTICS FOR INTEGRAL FINNE...IAEME Publication
Experimental investigations have been carried out in this paper to study the enhancement of heat transfer characteristics for cross flow low integral finned tube heat exchanger with using of (MgO) nanofluid. The study includes designing and manufacturing of test section from Pyrex glass with dimensions (2505001200) mm width, height and length, respectively. has a single copper tube with eight passes.. The low integral finned tube with (19 mm) inner diameter, (21 mm) root diameter and (24 mm) outer diameter. The fin height is (1.5 mm), thickness (1 mm) and the pitch is (2 mm). Air was used as a cooling fluid passing across the test tube with a range of velocities (1, 2, 3 and 4) m/sec. The inner side flow rates with a range of (2, 3, 4, 5 and 6) L/min. for water and for nanofluid.
Evaluation of Shell and Tube Heat Exchanger Performance by Using ZnO/Water Na...Barhm Mohamad
To examine and investigate the impact of nanofluid on heat exchanger performance, including the total heat transfer, the effect of friction factor, the average Nusselt number, and the thermal efficiency, the output heat transfers of a shell and tube heat exchanger using ZnO nanoparticles suspended in water has been conducted numerically. The governing equations were solved using finite volume techniques and CFD simulations with ANSYS/FLUENT Solver 2021. The nanoparticles volume fractions adopted are 0.2% and 0.35% that used in numerical computations under 200 to 1400 Reynolds numbers range. The increasing of temperature is approximately 13% from the bottom to the top of heat exchanger, while the maximum enhancement of Nusselt number is about 10%, 19% for volume fractions 0.2% and 0.35% respectively. The elevated values of the friction factor at the volumetric ratios of 0.2% and 0.35% are 0.25% and 0.47% respectively. The findings demonstrate that the performance efficiency of shell and tube heat exchanger is enhanced due to the increase in Nusselt number.
Effect Of Cuo-Distilled Water Based Nanofluids On Heat Transfer Characteristi...IJERA Editor
In this paper, the heat transfer and pressure drop characteristics of the distilled water and the copper oxide-distilled water based nanofluid flowing in a horizontal circular pipe under constant heat flux condition are studied. Copper oxide nanoparticles of 40nm size are dispersed in distilled water using sodium dodecyl sulphate as surfactant and sonicated the nanofluid for three hour. Both surfactant and sonication increases the stability of the nanofluid. The nanofluids are made in three different concentration i.e. 0.1 Vol. %, 0.25 Vol. % and 0.50 Vol. %. The thermal conductivity is measured by KD2 PRO, density with pycnometer, viscosity with Brookfield LVDV-III rheometer. The results show that the thermal conductivity increases with both temperature and concentration. The viscosity and density increases with concentration but decreases with temperature. The specific heat is calculated by model and it decreases with concentration. The experimental local Nusselt number of distilled water is compared with local Nusselt number obtained by the well known shah equation for laminar flow under constant heat flux condition for validation of the experimental set up. The relative error is 4.48 % for the Reynolds number 750.9. The heat transfer coefficient increases with increase in both flow rate and concentration. It increases from 14.33 % to 46.1 % when the concentration is increased from 0.1 Vol. % to 0.5 Vol. % at 20 LPH flow rate. Friction factor decreases with increase in flow rate. It decreases 66.54 % when the flow rate increases from 10 LPH to 30 LPH for 0.1 Vol. %.
Effect of nanofluid on heat transfer characteristics of double pipe heat exch...eSAT Journals
Abstract A nanofluid is a mixture of nano sized particles of size up to 100 nm and a base fluid. Typical nanoparticles are made of metals, oxides or carbides, while base fluids may be water, ethylene glycol or oil. The effect of nanofluid to enhance the heat transfer rate in various heat exchangers is experimentally evaluated recently. The heat transfer enhancement using nanofluid mainly depends on type of nanoparticles, size of nanoparticles and concentration of nanoparticles in base fluid. In the present paper, an experimental investigation is carried out to determine the effect of various concentration of Al2O3 nano-dispersion mixed in water as base fluid on heat transfer characteristics of double pipe heat exchanger for parallel flow and counter flow arrangement. The volume concentrations of Al2O3 nanofluid prepared are 0.001 % to 0.01 %. The conclusion derived for the study is that overall heat transfer coefficient increases with increase in volume concentration of Al2O3 nano-dispersion compared to water up to volume concentration of 0.008 % and then decreases. Keywords: Nanofluid, Heat Transfer Characteristics, Double Pipe Heat Exchagner, Al2O3 Nano-dispersion
The Force Convection Heat Transfer of A Nanofluid Over A Flat Plate: Using Th...AEIJjournal2
Advanced Energy: An International Journal (AEIJ) is a quarterly open access peer-reviewed journal that publishes articles which contribute new results in all areas of the Energy Engineering and allied fields. This multi disciplinary journal is devoted to the publication of high quality papers on theoretical and practical aspects of Energy Engineering.
The Force Convection Heat Transfer of A Nanofluid Over A Flat Plate: Using Th...AEIJjournal2
A drift-flux model is utilized to theoretically analyze the boundary layer flow and heat transfer of a
nanofluid over a flat plate. The concentration of nanoparticles at the plate is obtained using the solution of
the governing equations. Assuming a fixed magnitude of free stream velocity, the results show that the heat
transfer may enhance up to 22% or decrease about -7% by using nanofluids compared to the pure base
fluid.
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As a testament to academic excellence, this presentation is a showcase of the heights that can be achieved through relentless pursuit of knowledge. It encapsulates the essence of the student's journey as they progress towards their MPhil degree, solidifying their place within the academic community.
Join us in celebrating the pursuit of knowledge, innovation, and the boundless possibilities that mathematics offers. Whether you're a fellow researcher, a mathematics enthusiast, or someone simply curious about the beauty of numbers, this presentation promises to ignite your intellectual curiosity and leave you with a profound appreciation for the power of mathematical exploration.
Numerical Study of Heat Transfer in Ternary Nanofluid Over a Stretching Sheet...Atif75347
The new method of enhancing heat transfer through tri- hybrid nanofluid is discussed in the current study and represented in differential equation system.
Enhancement of Double-Pipe Heat Exchanger Effectiveness by Using Porous Media...Barhm Mohamad
In this paper, the rate of heat transfer by forced convection in a counterflow heat exchanger, at turbulent flow conditions were investigated experimentally, using
porous media and TiO2 Nanofluid to observe the behaviour of heat transfer with flow rate and volume concentration of nanoparticles t enhance heat transfer through it. 3
mm Steel balls (ε=39.12%) as a porous media completely filled to the inner pipe (core
pipe). The cold and hot water are used as working fluids through the inner and outer
pipes. Then using, the TiO2 nanofluid instead of cold water flowing through the porous
pipe to enhance heat characteristics. The effects of operating parameters include flow rate (4 LPM, 6 LPM, and 8 LPM), Reynolds number between (3000 – 7000), and
nanoparticle volume fraction (0.001, 0.002 and 0.003) on Convective heat transfer co-
efficient and Nusselt number. Effective thermal conductivity is increased when the
nanoparticle volume fraction is increased. The heat transfer coefficient increases with
decreasing nanofluid temperature, but the heating fluid's temperature has no
significant effect on the nanofluid's heat transfer coefficient. The results show that
porous media and TiO2-based nanofluid's improve heat transfer at flow rate of 4 LPM
by 35.4% and improve NTU and effectiveness at flow rate of 4LPM by 12.4%, and 24%,
respectively, when compared to pure water without porous media. This improvement
in thermophysical properties yielded high heat transfer of heat exchangers used in
process industries.
Entropy generation and heat transfer rate for MHD forced convection of nanoli...Barhm Mohamad
In this paper, magnetohydrodynamic laminar forced convection of nanoliquid in a rectangular channel with an extended surface, top moving wall and three cylindrical blocks is numerically studied. The Lattice Boltzmann method is used for the resolution of the governing equations. Validity of the numerical home elaborated FORTRAN code was made and good agreement was found with published results. It is interspersed in this work by the effects of the following parameters: Reynolds number (50≤Re≤200), Hartmann number (0≤Ha≤50), nanoparticles volume fraction (0≤φ≤4%) and Eckert number (0.25≤Ec≤1). The numerical solution shows that the local and average Nusselt numbers ameliorate when the value of Reynolds number, Eckert number, and the nanoparticles volume fraction are enhanced. But decreases when the Hartmann number is increased. The impacts of viscous dissipation on heat transfer rate and entropy generation are more noticeable in the presence of a magnetic field. The addition of 4% of nanoparticles enhances the local Nusselt number by about 7%.
Effect of Radiation on Mixed Convection Flow of a Non-Newtonian Nan fluid ove...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Improving the Cooling Performance of Automobile Radiator with TiO2/Water Nano...ijsrd.com
In this paper, forced convective heat transfer in a water based nanofluid has experimentally beencompared to that of pure water in an automobile radiator. Five different concentrations of nanofluids inthe range of 0.1-1 vol.% have been prepared by the addition of TiO2 nanoparticles into the water. The test liquid flows through the radiator consisted of 34 vertical tubes with elliptical cross section and airmakes a cross flow inside the tube bank with constant speed. Liquid flow rate has been changed in therange of 90-120 l/min to have the fully turbulent regime. Results demonstrate that increasing the fluid circulating rate canimprove the heat transfer performance. Meanwhile, application of nanofluid with low concentrations can enhance heat transfer efficiency up to 45% in comparison with pure water.
Axial Capacity Enhancement of CFRP Confined Columns Made of Steel Fiber Reinf...IOSRJMCE
Results of the experimental study on the axial compressive behavior of steel fiber reinforced concrete (SFRC) wrapped with fiber reinforced polymer (FRP) have been presented in this paper. A total of 18 concrete cylinders were tested under axial compression. The effects of steel fiber parameters were investigated which includes fiber aspect ratio (AR) and fiber volume fraction (VF). The concrete cylinders were divided into groups of confined and unconfined ones. In accordance with previous study, it was found that, FRP confined cylinders showed greater axial stress than that of unconfined specimens. Although the presence of steel fiber increases the peak axial stresses for both confined and unconfined group of specimens, but no significant change of peak axial stress (and peak strain) has been observed in both confined and unconfined group due to increase of fiber volume ratio. But with the increase of fiber aspect ratio, the peak axial stresses of both unconfined and FRPconfined cylinders were found to slightly decrease. It was also observed that, concrete specimens reinforced with internal steel fiber absorbed much higher energy than that of unreinforced ones.
Smart Response Surface Models using Legacy Data for Multidisciplinary Optimiz...IOSRJMCE
One of the key challenges in multidisciplinary design is integration of design and analysis methods of various systems in design framework. To achieve Multidisciplinary Design Optimization (MDO) goals of aircraft systems, high fidelity analysis are required from multiple disciplines like aerodynamics, structures or performance. High Fidelity Analysis like Computer-Aided Design and Engineering (CAD/CAE) techniques, complex computer models and computation-intensive analyses/simulations are often used to accurately study the system behaviour towards design optimization. Due to high computational cost and numerical noise associated with these analyses, they cannot be used effectively. The use of surrogates or Response Surface Models (RSM) is one approach in Multi Disciplinary design optimization to avoid the computation barrier and to take care of artificial minima due to numerical noise. This paper brings out a method based on use of “Smart Response Surface Models" to generate surrogate models, with its validated subspace, in the design space around the point of interest with the use of legacy data for MDO. The method has been evaluated on three test cases, which are created based on High Speed Civil Transport (HSCT) Multidisciplinary Design Optimization Test Suite
Experimental and Numerical Modal Analysis of a Compressor Mounting BracketIOSRJMCE
Experimental modal analysis has grown steadily in popularity since the advent of the digital FFT spectrum analyzer in the early 1970’s. Today, impact testing (or bump testing) has become widespread as a fast and economical means of finding the modes of vibration of a machine or structure. In this paper, it presents the experimental and numerical modal analysis of a compressor mounting bracket (CMB). The dynamic behavior of CMB is investigated through impact testing. The three-dimensional finite element models are constructed using Altair HyperMesh and an numerical modal analysis is then performed to generate natural frequencies and mode shapes in the three-orthogonal directions. The finite element model agrees well with the experimental tests and eventually it helps the designer to design upfront with much lesser cost and time of experimentation
Analysis and Design Aspects of Support Measures of Main Caverns of Karuma Hyd...IOSRJMCE
The Power house complex of Karuma Hydropower project comprises three main caverns i.e Power house, Transformer Hall and Tailrace surge gallery set at a depth of about 80m in mainly granitic gneiss rock medium. The cavern has been oriented in a N141° direction based on engineering considerations. The principle stress direction is also found nearly parallel to the axis of the caverns and thus the present orientation satisfies both engineering and geotechnical criteria. The support by way of rock anchors and SFRS/ Plain shotcrete has been provided based on analysis using phase 2 software. The underground caverns lie in low geostress field and therefore numerical simulation of excavation of these caverns were done to understand the rock mass behavior during excavation and thus help in design of excavation sequence and rock support. The excavation of all three caverns has since been completed and concrete works are in progress. This paper sums up the 3D simulation analysis of the rock medium and the proposed rock support system for the three caverns.
A Review: Effect of Laser Peening Treatment on Properties And Life Cycle of D...IOSRJMCE
- In this review, the effect of laser peening process with and without protective coating is discussed over the different material and it is observed that the residual stress are induced in material surface up to some depth according to process parameters of LSP. Fatigue strength and micro-hardness of material are enhance by inducing residual stresses which further depends on process parameters and material properties.
Experimental Evaluation of Refrigerant Mixtures as Substitutes for HFC134aIOSRJMCE
Refrigerant R134a base systems has higher GWP value that's why the conversion of same into ecofriendly system is the major concern for refrigeration industry. This investigation focuses on mixture ratio of pure hydrocarbon R290 and R600a used in 200 liter domestic refrigeration system by certain changes in mass ratio of refrigerants. In the present work, first of all the effect of mass ratio of HCM refrigerants on the performance of the system was investigated. HCM of R600a/R290 (60/40 by wt. %) gave better performance than that of HCM R600a/R290 (70/30 by wt. %), R600a/R290 (50/50 by wt. %) and R134a. The mass ratio of HCM (R600a/ R290) refrigerants was optimized for the performance parameter with respect to evaporating temperature. The COP of R600a/R290 (60/40 by wt. %) mixture was higher than that of R600a/R290 (50/50 by wt. %) by 21.9% and 17.6% at -5 0C and 5 0C evaporative temperature respectively. COP decreased as propane mass fraction in HCM increased above 40%.
Simulation and Analysis of Electrolyte Flow Pattern in ECM for L-Shaped Tool ...IOSRJMCE
Electrochemical machining (ECM) is a non-traditional machining method based on principle of reverse electroplating (anode loses metal to cathode). ECM uses principal of electrolysis to remove metal from the work piece. Due to improper tool design of complicated shapes, there are chances of passivation and boiling of electrolyte in ECM process that causes poor machining. In this present study three dimensional flow pattern of ECM process has been simulated using Computational Fluid Dynamics (CFD) in L-shaped tool models. This work is for optimizing the design of L-shaped tool and to study the flow pattern, current density distribution, velocity profile, temperature pattern, turbulence and final shape change of workpiece top surface. ANSYS was used for design and simulating this CFD problem, the geometrical model consists of a circular workpiece made with Iron, 20% brine solution (NaCl) as electrolyte and L-shaped copper tool with different kind of grooves.
Study on Transverse Displacement in Composite Laminated Plates across Thickne...IOSRJMCE
: In this paper main focus is given on alternative ways of thermal load applied through the thickness of laminated composite plate. Research has assumed gradient or constant thermal profile along the thickness of the plate. Laminated composite is a complex material therefore assumed loading profiles may not obey the gradient or constant thermal profile path therefore, as a research in all total 10 thermal profiles are studied. The results in tabular and graphical forms are presented along with discussion. First Order Shear Deformation Theory (FOST) is used for analysis. Various quantities, namely in plane as well as transverse displacements and stresses are obtained when thermal load is applied in various orientations along the thickness of the plate. Main focus in this article is analysis of transverse shear displacement and results are presented in tabular and graphical form.
Eigenvalue Buckling Computation and Impact on Pipeline Wall Thickness and Sub...IOSRJMCE
Submarine pipelines used in the transportation of hydrocarbon in the oil and gas industry are usually subjected to external hydrostatic pressure and compressive stresses resulting in susceptibility to buckling and loss of structural stability. The objective of the present work was to examine influence of wall thickness on eigenvalue buckling load and hydrostatic pressure on ocean depth. Linear buckling analysis was conducted employing finite element method using ANSYS software package and the simulation was conducted varying wall thickness and ocean depth. The investigation showed collapse buckling pressure decreased linearly with ocean water depth but increased with thickness increment. Pipeline buckling failure can be minimized with wall thickness optimization design and selection.
Mechanical Analysis of an Ixtle Based Cable for Its Use in ArchitectureIOSRJMCE
Thegrowing conscience for sustainability has driven humanity to attempt to go back to basic and natural materials, such as the use of earth, and the incorporation of biopolymers and fibers, producing, among other things, a diverse kind of structural elements applied to architecture. Natural fibers can be a good alternative given its abundance and the great number of possibilities in regard to its use.The lechuguilla agave Torrey is a plant, belonging to the Agavaceaefamily, that can be found in several zones of Mexico, and from it, the fiber known as ixtle, generally used in the elaboration of crafted structures, can be obtained.The present paper has studied the stress resistance of the ixtle fibers, of this specie and its qualitative effect when dosed in an earth mixture to be used as mortar for wall coating. The study consisted in stress testing the fibers separately and entwined for its possible use. In the case of the mortar, different samples of clay soils were taken, stabilized and dosed with and without the fiber, observing the effect when used to cover a block surface and determining the material’s resistance to compression. It has been found that it is possible to add fibers in mixtures and obtain a greater adherence in the block’s surface, besides, it can be added to clay samples for revoke obtaining resistances of 18kg/cm2. Finally it was obtained that by weaving the fibers, the stress resistance can be enhanced by over 600%.
Application of Artificial Neural Networking for Determining the Plane of Vibr...IOSRJMCE
In this paper a new approach for Artificial Neural Networking using Feed Forward Back Propagation Method and Levenberg-Marquardt backpropagation training function has been developed using Java Programming, where by directly feeding the RMS and Phase values of vibration, the unbalance plane can be detected with minimum error. In a Machine Fault Simulator RMS value and phase values of vibrations are collected from the four accelerometers placed in X and Y direction of Left and Right Bearings .Further these data are fed into the neural network for training purpose. In the testing phase of the neural network, the plane of vibration has been determined using different training algorithms available in MATLAB. Their prediction values have been compared with the actual value, errors for different training algorithms are calculated and a conclusion has been drawn for the best training function available for this current research work.
Effect of Stiffening System on Building Resistance to Earthquake ForcesIOSRJMCE
Multi-story steel buildings of various heights under the action of earthquake force are analyzed by using time-history analysis technique. The ground motion records of El Centro, California in 1940 are considered in this study. Different types of stiffening systems (bracing and shear walls) are used for the considered buildings. The main objective of this study is to evaluate the response of steel structures subjected to earthquake excitation and to investigate the effect of various stiffening systems in improving the response of these buildings. The finite element method of SAP 2000 V17program is used in the analysis. A static analysis is conducted to obtain an indication on the stiffness of the studied stiffening models in order to interpret the stiffness effect on the response of the structures under the seismic load. It is found that, the natural period of a structure is highly affected by the height of the structure and the used stiffeningsystem. It is inversely proportional with the stiffness and directly proportional with the height of the structure. It is concluded that the roof displacement andits maximum value at a specific momentdoes not give a clear indication for the behavior of building. Therefore the full time response of the building must be considered. Also it has been concluded that it is not necessarily when the stiffness of a building increases, the roof or any story displacement of the building decreases under earthquake load.
Resource Optimization of Construction Project Using Primavera P6IOSRJMCE
Construction projects are unique in nature, having their own difficulties, uncertainties and risks, posing never-ending questions concerning the resources and costs. There is always a conflict between ‘how much it will cost?’ and ‘where to raise the finances from?’. The success of a project depends upon the efficiency with which the project management gets the work done by utilizing the planned resources of men, materials, machinery, money and time.. In large scale projects, preparing an accurate and workable plan is very difficult. Resources are required to carry out specific tasks in a project, but the availability of resources within a given firm is always limited. While preparing the schedule structure, the Project Manager might schedule certain tasks in parallel. In such cases it might be possible that the same resource is being used in both the parallel tasks, while its availability is limited. This paper emphasises how the Project Manager could resolve such conflicts by using Resource Balancing in modern softwares such as Primavera (P6) R8.3, to reduce laborious computations. In this paper, the Resource Balancing techniques namely smoothing & leveling have been investigated in detail. This paper uses a case study in order to portray how Resource Balancing could be done using Primavera p6 and its effects are on the duration and cost of the entire project.
Optimization of Electrical Discharge Machining Process Parameters using SCM42...IOSRJMCE
Electrical discharge machining is a nonconventional machining process which enables machining of complex and intricate shapes, hard materials that are precise and difficult to machine such as heat treated tool steels, composites, super alloys, ceramics, carbides, heat resistant steels etc. The process involves spark erosion in the presence of dielectric fluid. In this work SCM 420low alloy steel is the material used for the machining purpose with electrolyte copper as tool. This work investigates effect of process parameters peak current (IP), Pulse on time (Ton) and gap voltage (Vg) on Material removal rate (MRR) and surface roughness (Ra). Response surface methodology is used for experimental design. The suggested model can be used in the different manufacturing firms by selecting right combination of process parameters to achieve optimal values of output responses.
Efficient Mass Participation Ratio of Building with BasementIOSRJMCE
This study investigates the effect of basement floor(s) on seismic analysis of buildings. Considering the basement floor(s) in the seismic analysis using response spectrum method creates a problem regarding the mass participation ratio (MPR) which should not be less than 90% of total mass of building as a requirement by the code. While the MPR depending on the number of mode shapes used in the modal analysis, some codes allow to neglect this ratio with condition that use a reduced number of mode shapes with some restrictions to calculate it. A parametric study was performed to investigate this reduced number of mode shapes and a new restriction was performed to calculate it. The natural period, the top lateral displacement and the internal straining actions using the reduced numbers of mode shapes were compared with those of building where using the number of mode shape which can reach 90% MPR. Finite element simulations are conducted using ANSYS program to investigate the effect of basement floor(s). Results are presented for different buildings by considering different numbers of floors for the super structure (2, 5, 10, 15 and 20), the number of basements (1 and 3) and spring support stiffness, which simulate the effect of soil. The numerical results of the considered cases show that the requirement of 90% MPR can be neglect by using a reduced number of mode shapes and some restrictions stated in this study. In such case the accuracy will be not less than 95%.
Literature Review of Experimental Study on Load Bearing Masonry WallIOSRJMCE
Masonry load bearing wall subjected to vertical concentric and eccentric loading may collapse through instability. In this Paper the buckling behavior of masonry load bearing wall of different slenderness ratio were investigated by many researcher has been reviewed via testing a series of scale masonry wall subjected to concentric and eccentric vertical loading. The influence of nonlinear behavior of interface element, slenderness ratio and various end conditions have been investigated together with the effect of different end eccentricity of vertical load.
Structural Design of Concrete Structure Using E-TabsIOSRJMCE
In the world of technology and evolution, the field of civil engineering has also grown in various dimensions. Earlier the analysis and sustainability of the civil structures used to be paper based calculations which led to insufficient accuracy of analysis and variable factors affecting the failure of the structure through inevitable instances. But with the help of integration of various engineering fields, this determination of various characteristic changes, durability, deformation or failure caused due to hidden factors which are left out in the manual calculations i.e. paper based have converted and led this system to whole new level. Now a number of software are developed for analysis, computation and management of building of civil structures which are highly precise. This document provides the various uses, merits of the software E-Tabs in the construction field and in the analysis of the concrete structures as well as steel structures.
Finite Element Analysis of Opening Plate, Fixed Tube Sheet and Floating Sheet...IOSRJMCE
)A heat exchanger is a device that is used to transfer thermal energy (enthalpy) between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures and in thermal contact. Opening Plate, Fixed Tube Sheet and Floating Tube Sheet is a part of Shell & Tube Heat Exchanger, used in refinery and oil & gas production. Typically, shell & tube heat exchanger can be considered as a pressure vessel subjected to uniform internal pressure. Hence the shell & tube heat exchanger in various design and operating conditions needs to be checked and verified for soundness of participating components. Opening, Fixed tube and Floating sheet plate due to uniform internal pressure in the shell & tube heat exchanger can produce high-localized stress and deformation. If the components are not designed for these conditions, safety of the equipment is at stake. Hence check for the stress and displacement of the shell & tube heat exchanger during operating condition is carried out using finite element analysis software and observed that shell & tube heat exchanger is free from collapse and serviceability failure.
Influence of Combine Vertical Irregularities in the Response of Earthquake Re...IOSRJMCE
This study investigates the effect of frame set-back with vertical irregularity in height on accuracy of Pushover Analysis for predicting target displacement, story drifts, base shear and performance point. The behavior of high rise building during strong earthquake motion depends on the distribution of mass, stiffness and strength in both horizontal and vertical planes of the buildings. The Indian IS code 1893:2002(Part 1) has pointed out of different structures irregularities like plan irregularity and vertical irregularity. In this study the seismic performance of G+ 16 storey having combine effect of vertical irregularity with R.C building are examined using Non Linear Static Analysis (Pushover Analysis). The Base shear, lateral displacement, storey drift and performance points are the response parameters use to quantify the performance of the structure. These irregularities are responsible for structural collapse of buildings under the action of dynamic loads. Five different types of building geometry are taken one regular and four irregular frames. The all buildings are modeled and analyzed in software SAP 2000. It was found that irregularity in elevation of the building reduce the performance level of structure.
Straight Bevel Gears Manufacturing Analysis by Conventional Powder Metallurgy...IOSRJMCE
In this paper it was proposed the manufacture of a component of the agricultural sector machine with conventional Powder Metallurgy (PM) techniques. The proposed process was developed with a Straight Bevel Gears, which is currently manufactured by other manufacturing processes, such as machining and forming. The gearwheel is part of a gearbox that replaces speed reduction. The component developed by powder metallurgy is low-carbon iron, in relation to Ni (nickel), Cu (copper) Mo (molybdenum) in large quantities. It was sought to verify the dimensional behavior with Statistical Process Control (SPC) techniques and also its properties through the analysis of the densities obtained in the gears during the powder metallurgy process. It was found that the parts fulfilled the requirements for coupling operation, such as those processed by other processing methods. The mechanical properties checked fully met the minimum requirements for these components. The chemical composition generated for the sprocket also pleased satisfied for this use.
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.
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/
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
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.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Immunizing Image Classifiers Against Localized Adversary Attacks
Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model at different Reynolds Numbers
1. IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE)
e-ISSN: 2278-1684,p-ISSN: 2320-334X, Volume 14, Issue 1 Ver. V (Jan. - Feb. 2017), PP 44-55
www.iosrjournals.org
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 44 | Page
Study of Forced Convection Heat Transfer with Single phase and
mixture phase Nanofluid Model at different Reynolds Numbers
Mir Moniruzzaman Mobin1
, MD Minal Nahin2
1
(Dept. of Mechanical Engineering, Bangladesh University of Engineering and Technology, Bangladesh)
2
(Dept. of Mechanical Engineering, Indiana University–Purdue University Indianapolis, USA)
Abstract: In this study, forced convection heat transfer of nanoliquids is done using both single-phase and
mixture-phase models and the results are compared with experimental results. The governing equations of the
study here are discretized using the finite volume method. Hybrid differencing scheme is used to calculate the
face values of the control volumes. A code is written using SIMPLER algorithm and then solved using the
MATLAB engine. The mixture-phase model studied here, considers two slip mechanisms between nanoparticle
and base-fluid, namely Brownian diffusion and thermophoresis. Al2O3-water nanofluid is used for the study of
nanofluid and the study shows significant increase in convective heat transfer coefficient while the mixture-
phase model demonstrates slightly lower values than the single-phase model. The study is done with various
nanoparticle concentrations and Reynolds numbers. With increasing particle concentration and Reynolds
number, the convective heat transfer coefficient increases and as well as the shear stress. For low
concentrations of the nanoparticle, Nusselt number is slightly lower than the base fluid and as the concentration
increases, the Nusselt number also rises higher than the base fluid.
Keywords - Nanofluid, single-phase, mixture-phase, convective heat transfer, shear stress, nanoparticle
volume fraction.
I. Introduction
Conventional heat transfer fluids, such as water, engine oil, ethylene glycol etc. have very limited
convective heat transfer coefficient. Maxwell [1] showed the possibility of increasing thermal conductivity of a
mixture by introducing more solid particles in a fluid. Following the Maxwell’s work, numerous theoretical [2-
3] and experimental studies [4-5] were done with suspended solid particles in fluids and gases. These mixtures
demonstrate a considerable increase of heat transfer coefficient. Because of the technological developments of
the recent years, nano-sized particles are now being used with fluids which are called nanofluids.
Choi [6] studied the enhancement of thermal conductivity enhancement by suspending nanoparticles.
Nanofluid is a mixture of fluid and very fine sized particles of size in the range of 1-100nm. Early researchers
have worked mostly on determination of effective thermal conductivity and viscosity of nanofluids [7-10].
Masuda et al. [11] reported an increase in thermal conductivity of liquid suspensions of γ-Al2O3, SiO2 and TiO2
nanoparticles. Lee et al. [12] studied the thermal conductivity enhancement of various metal oxide suspensions.
They found that the thermal conductivity of the nanofluids may increase by about 20% more than the base fluid
for a very little volume fraction of nanoparticles (say 1-5%). These enhancements depend mainly on the
nanoparticle size and form, volume concentration, thermal properties of both constituents etc. Correlations were
developed for effective conductivity and viscosity for various nanofluids as a function of base fluid properties
and volume fraction of nanoparticles. Das et al. [13] experimentally studied the temperature dependence of
thermal conductivity of nanofluids. Kakaç et al.[14] summarized the important published articles on forced
convection heat transfer of nanofluids. Research works on fluid flow and convective heat transfer of nanofluids
in forced and free convection flows were reviewed by [15-17].
Numerical works on nanofluids are performed using two models: the single-phase model and the two-
phase model. In the single-phase model, the basic hypothesis is that the nanofluid behaves like a single-phase
fluid with enhanced thermo-physical properties due to the inclusion of nanoparticles. Maїga et al. [18]
investigated the laminar forced convection flow of nanofluids considering a system of uniformly heated tube
and another system of parallel, coaxial and heated disks. Among the two nanofluids studied, Ethylene Glycol–
Al2O3nanofluid appears to offer a better heat transfer enhancement than water–Al2O3nanofluid. Demir et al. [19]
studied forced convection flows of nanofluidsusing TiO2–water and Al2O3–water nanofluids in a horizontal tube
with constant wall temperature. In the two-phase model, different factors resulting from nanoparticle immersion
such as gravity, Brownian diffusion, thermophoresis, sedimentation, dispersion etc. are considered. Two-phase
models can be Eulerian-Eulerian, Eulerian-Lagrangian, mixture model etc. [20-22].Behzadmehr et al. [20] used
a two-phase mixture model to investigate the turbulent convection with nanofluids in a circular tube. They found
two-phase results are more precise than the homogenous modeling (single-phase) by comparing the results with
2. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 45 | Page
experimental ones. Bianco et al. [21]studied forced convection of nanofluids in a circular pipe using both single
and mixture model. They found a maximum difference of 11% in the average heat transfer coefficient between
the single and two phase model. Kalteh et al. [22, 23] studied the forced convection heat transfer of nanofluids.
Buongiorno [24] theoretically developed a mixture model by considering slip mechanisms that can produce a
relative velocity between the nanoparticles and the base fluid. The slip mechanisms considered were inertia,
Brownian diffusion, diffusiophoresis, thermophoresis, fluid drainage, Magnus effect, and gravity. Brownian
diffusion and thermophoresis were the only important slip mechanisms in nanofluids and based on the result,
Buongiorno proposed a two-component four-equation non-homogeneous equilibrium model for nanofluids.
Allahyari et al. [25] investigated the mixed convection of alumina-water nanofluid in an inclined tube which is
heated at the top half surface.Sidik et al. [26] studied the thermal performance of fins cooled either by water or
alumina-water nanofluid in a channel by lattice Boltzmann method.
Wen and Ding [27] had performed an experimental study of the convection heat transfer of nanofluids
in the entrance region under laminar flow conditions. They found considerable enhancement of convection heat
transfer and it was much higher than that of solely for the enhancement of thermal conduction. Heris et al. [28]
studied the convective heat transfer of alumina-water nanofluid. They found much higher heat transfer
coefficient than the prediction of single phase correlation. Aqueous suspensions of TiO2 and CNT nanofluids
were studied experimentally by [29, 30] to investigate the heat transfer and flow behaviors. Significant
enhancement of the convective heat transfer was observed which depends on the Reynolds number, CNT
concentration and the pH value. Chen et al. [31] studied the heat transfer and flow behaviors of aqueous
suspensions of titanate nanotubes. They found much higher convective heat transfer coefficient, which is not
merely for the enhancement of thermal conductivity. Moraveji and Esmaeili [32] did comparison between
single-phase and two-phases CFD modeling of laminar forced convection flow of nanofluids in a circular tube
under constant heat flux.
Nanofluids are fluids with immersed nanoparticles in it. It demonstrates much higher convective heat
transfer coefficient than conventional working fluids. The present article studies the forced convection heat
transfer of nanofluids using both single-phase and mixture-phase models of nanofluids. For the mixture model,
the study uses the one given by Boungiorno [24]. The study focuses on the variation of convective heat transfer
coefficient, Nusselt number, wall shear stress etc. with Reynolds number for various nanoparticle volume
fractions. The study also discusses the volume fraction distribution of the nanoparticles.
II. Mathematical Modeling
Fluid flow and Heat transfer consists of continuity, momentum and energy equations. Some
assumptions are made to simplify the governing equations. The assumptions are as following: 1.
Incompressible flow 2. Axi-symmetric study 3. Steady-state flow 4. No external forces 5. Dilute solution
( ) 6. Temperature independent properties.
2.1. Governing equations:
The governing equations of the mixture model are different than the single-phase model. The
governing equations of the single-phase model are:
Continuity equation:
Momentum equation:
Energy equation:
The governing equations of the mixture model contain equations (1) and (2) of the single-phase model. The
energy equation of the mixture model is as following:
Energy equation:
The two additional terms on the right side of equation (4) comes due to the heat transfer by virtue of
nanoparticle diffusion. In the equation, is the heat capacity of the nanofluid and is the heat
capacity of the nanoparticle.
The mixture model includes another equation which is the nanoparticle continuity equation. The equation is as
following:
Continuity equation for nanoparticle:
3. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 46 | Page
Here, DB represents the Brownian diffusion coefficient, given by the Einstein-Stokes’s equation, and DT
represents the thermophoretic diffusion coefficient of the nanoparticles.
here, kB is the Boltzmann constant, dnp is particle diameter, k and knp are the conductivities of the base fluid and
nanoparticle respectively.
2.2. Boundary Conditions:
A circular tube of length 1.5 m and inner diameter of 13.5 mm is taken for the study. The fluid is
assumed to have a uniform axial velocity V0, and temperature T0 (=293 K) profiles at the tube inlet section. At
the exit section, the fully developed conditions are applied, which means all axial derivatives are zero. On the
tube wall, no-slip and uniform heat flux boundary conditions are applied. For the mixture model, boundary
conditions are also needed for the nanoparticle volume fraction. At inlet, uniform volume fraction and at wall,
zero nanoparticle mass flux boundary conditions are applied. At outlet, axial derivative of volume fraction is
assumed zero. The different thermo-physical properties are calculated at temperature T0. Both the flow and
thermal fields are assumed axi-symmetric.
2.3. Thermo-Physical Properties
The thermo-physical properties used in this study are calculated using the following equations.
The nanofluid density is the average of the nanoparticle and base fluid densities:
where, the subscripts nf, p and bf refer to the nanofluids, nanoparticles and base fluid respectively.
The effective specific heat of nanofluid can be calculated by the following equation as reported in [9, 18].
Different researchers have studied to calculate the effective viscosity of different nanofluids [11, 12]. Nguyen
et al. [33] proposed the following correlation for Al2O3-water nanofluid as given in equation (8).
Various correlations by different researchers can be found for the effective conductivity of different nanofluids
[9, 11, 28]. The thermal conductivity given by Pak and Cho [9] for Al2O3-water nanofluid is used in this study
which can be correlated as follows:
Table 1: Thermo-physical properties of Al2O3 and water
Thermo-physical Properties Al2O3 Water
3880 998.2
733 4182
--- 9.93e-4
36 0.597
III. Numerical Modeling
In this study, finite volume method is used to discretise the governing equations of single-phase and
mixture models of the nanofluid. For discretizing, the physical space is divided into many small sub-domains
which are called control volumes or cells. The shape of the cells is taken rectangular which is known as
structured grids. The partial differential equations are recast on these cells and approximated by the nodal
values or central values of the control volumes. Hybrid differencing scheme is used to calculate the cell face
values from the cell node values. Staggered grids are used during the storing of the variables. Iterative solution
strategy of SIMPLER algorithm is used to deal with non-linearity and pressure-velocity linkage of the flow
4. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 47 | Page
equations. Grid independence test is performed and 160 and 80 nodes in the axial and radial direction are found
satisfactory for the study.
Fig 1: Flowchart of SIMPLER algorithm
The following equations are used to calculate the various parameters:
Wall shear stress:
Average wall shear stress:
Local convective coefficient:
Average convective coefficient:
Local Nusselt number:
Average Nusselt number:
Average velocity:
5. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 48 | Page
Bulk temperature:
3.1. Code Validation:
The nanofluid study is done by writing a code using FVM method. To validate the code, Nusselt
numbers calculated from pure water flow is compared with the Nusselt number correlation for constant wall
heat flux given by Shah and London [34]. The two results are plotted in Fig. 1. The two plots are almost
identical with present results slightly higher in the developing flow region and it gradually decreases to slightly
lower values in the fully developed region than the Shah and London [34] results. The above trend of variation
of the present results can be attributed to the use of temperature independent properties. The Shah and London
correlation is given by equation (10).
where,
z/L
0.0 0.2 0.4 0.6 0.8 1.0
hz(W/m
2
K)
200
300
400
500
600
700
800
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
Fig. 2: Code validation of nanofluid study
IV. Results and Discussions
Simulation for nanofluidflow in the circular tube is carried out with nanoparticle volume fraction,
at three different Reynolds numbers of 200, 400 and 600. A uniform heat flux of
2500 W/m2
is considered during the study. Change of different parameters like convective heat transfer
coefficient, Nusselt number, shear stress etc. are investigated for nanoparticle immersion to the base fluid.
Fig. 3(a) shows the profiles of axial velocity along pipe radius at different length sections for pure
water at Reynolds number of 200. The plot shows that for z/L=0.2 and 0.3, the two graphs almost coincide i.e.
the flow is fully developed at z/L=0.2. Fig. 3(b) shows the axial velocity profiles for various nanoparticle
concentration at z/L=0.3 for the mixture model. The velocity profiles are fully developed and are nearly
identical with very small increase near the wall. The velocity of the mixture model slightly increases near the
wall because of the reduced viscosity near the wall. The viscosity reduces near the wall because of the reduced
nanoparticle concentration near the wall.
6. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 49 | Page
(a) r/R
0.0 0.2 0.4 0.6 0.8 1.0
V/V0
0.0
0.5
1.0
1.5
2.0
z/L=0.02
z/L=0.06
z/L=0.1
z/L=0.2
z/L=0.3
(b) r/R
0.0 0.2 0.4 0.6 0.8 1.0
V/V0
0.0
0.5
1.0
1.5
2.0
j=0.00
j=0.02
j=0.04
Fig. 3: Axial velocity profiles (a) at various locations for pure water, (b) at z/L=0.3 for various nanoparticle
volume concentration.
Dimensionless temperature is plotted along pipe radius in Fig. 4(a) at various locations along the axial
direction at Re=200. Thermal entrance length is larger length than the hydrodynamic entrance length. The plots
for z/L=0.4, 0.7, and 1.0 are almost identical, meaning a thermally fully developed flow. Fig. 4(b) shows the
dimensionless temperature at outlet for various volume concentrations. The plots are almost identical. With the
increase of volume concentration, Prandtl number increases only slightly. As a result, not much variation is seen
in the plots of dimensionless temperature.
(a) r/R
0.0 0.2 0.4 0.6 0.8 1.0
T
*
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
z/L=0.03
z/L=0.20
z/L=0.40
z/L=0.70
z/L=1.00
(b) r/R
0.0 0.2 0.4 0.6 0.8 1.0
T
*
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
=0.00
=0.02
=0.04
Fig. 4: Dimensionless temperature (a) at various locations for pure water, (b) at z/L=1.0 for various volume
concentration.
The local convective heat transfer coefficient is plotted in Fig. 5(a) for various nanoparticle
concentrations at Re=200. The S-P and M-P stands for single-phase and mixture-phase respectively. The plots
show an increasing convective heat transfer coefficient with increasing particle concentration. The single-phase
and the mixture-phase models provide almost same results for most of the pipe length. Towards the end of the
pipe, the difference between the single-phase and mixture-phase model increases whereas mixture-phase model
provides lower values. At the exit section, the increment is 15% for single-phase model and 13% for mixture-
phase model for nanoparticle volume fraction of 2%. For volume fraction of 4%, the increment is 31% for
single-phase and 26% for mixture-phase model. The mixture model shows lower increment in heat transfer
coefficients than the single-phase model. This is because the nanoparticle volume fraction reduces near the wall
and as a result thermal conductivity gets reduced near the wall. Because of the reduced particle concentration,
velocity increases slightly near the wall but not enough to compensate for the reduced conductivity. Also, the
two additional terms in the right side of mixture-phase energy equation is very small to make noticeable
difference in the convective coefficient. Fig. 5(b) and Fig. 5(c) show the plots of local convective heat transfer
coefficient for Reynolds numbers of 400 and 600. It is seen that the plots have shown almost similar trend of
Fig. 5(a). Finally, the average convective heat transfer coefficient for various nanoparticle concentration and
Reynolds number is plotted in Fig. 5(d). The figure shows that the convective coefficient increases with
Reynolds number and nanoparticle volume fraction. The difference in the convective coefficient of single-phase
and mixture-phase decreases with the Reynolds number. The average convective coefficient increases by about
35% for 4% volume fraction of nanofluid found by single-phase model of study.
7. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 50 | Page
(a) z/L
0.0 0.2 0.4 0.6 0.8 1.0
hz(W/m
2
K)
200
300
400
500
600
700
800
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(b) z/L
0.0 0.2 0.4 0.6 0.8 1.0
hz(W/m
2
K)
200
300
400
500
600
700
800
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(c) z/L
0.0 0.2 0.4 0.6 0.8 1.0
hz(W/m
2
K)
200
300
400
500
600
700
800
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(d) Re
200 300 400 500 600
hav(W/m
2
K)
200
250
300
350
400
450
500
Base Fluid (=0.00)
Nanofluid (=0.02, S-P)
Nanofluid (=0.02, M-P)
Nanofluid (=0.04, S-P)
Nanofluid (=0.04, M-P)
Fig. 5:convective heat transfer coefficient for various volume fractions at (a)Re=200 (b) Re=400 (c) Re=600 (d)
different nanoparticle volume fractions at different Re
The local Nusselt numbers are plotted in Fig. 6(a), Fig. 6(b) and Fig. 6(c) for Reynolds numbers of 200,
400 and 600 respectively. All these graphs have the same trend as that of the convective heat transfer
coefficient. The Nusselt numbers of different nanofluids depend on the nanofluid model and the nanoparticle
concentration. Fig. 6(a) shows that, for mixture model study, the Nusselt number is higher in the entrance region
and it falls below the Nusselt number of base fluid in the developed region. The single-phase model gives
slightly higher Nusselt number than the base fluid in all sections of the pipe.
(a) z/L
0.0 0.2 0.4 0.6 0.8 1.0
Nuz
4
5
6
7
8
9
10
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(b) z/L
0.0 0.2 0.4 0.6 0.8 1.0
Nuz
4
5
6
7
8
9
10
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
8. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 51 | Page
(c) z/L
0.0 0.2 0.4 0.6 0.8 1.0
Nuz
4
5
6
7
8
9
10
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(d) Re
200 300 400 500 600
Nuav
5.0
5.5
6.0
6.5
7.0
7.5
Base Fluid (=0.00)
Nanofluid (=0.02, S-P)
Nanofluid (=0.02, M-P)
Nanofluid (=0.04, S-P)
Nanofluid (=0.04, M-P)
Fig. 6: Local Nusselt number for various volume fractions at (a)Re=200 (b) Re=400 (c) Re=600 (d) different
nanoparticle volume fractions at different Re
The average Nusselt number is plotted in Fig. 6(d) for various nanoparticle volume fractions at different
Reynolds numbers. The variation of average Nusselt number is very small with the nanoparticle volume
percentages. For 2% volume fraction of nanoparticle, the mixture-phase model gives slightly lower average
Nusselt number while the single-phase model gives slightly higher average Nusselt number than the base fluid.
For 4% volume fraction, both the single-phase and mixture-phase model gives higher average Nusselt number
than the base fluid.
The local shear stress is plotted for different volume concentration at Reynolds number of 200, 400 and
600 in Fig. 7(a), Fig. 7(b) and Fig. 7(c) respectively. The plots show that the stress drastically drops to an almost
constant value near the inlet section. The shear stress is almost constant at later sections of the pipe. The shear
stress increases with nanoparticle volume fraction and the relative increment with respect to base fluid is higher
for 4% volume fraction than 2% volume fraction of nanoparticles. The mixture-phase model gives lower values
of shear stress than the single-phase model as the viscosity near the wall reduces in the mixture-phase model.
The average shear stress is plotted in Fig. 7(d) for various volume fractions at different Reynolds numbers. The
average shear stress increases with Reynolds number at an almost constant rate. The average shear stress
increases by 40% and 140% than the base fluid for 2% and 4% volume fraction of nanoparticles for single-phase
study. For mixture-phase study, the increment is 35% and 124% for 2% and 4% volume fraction of
nanoparticles respectively. As both the velocity and effective viscosity of the nanofluid increases with the
nanoparticle volume fraction, the relative increment of wall shear stress increases with the increase in
nanoparticle volume fraction as found in Fig. 7(d).
z/L
0.0 0.2 0.4 0.6 0.8 1.0
s(N/m
2
)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(a)
z/L
0.0 0.2 0.4 0.6 0.8 1.0
s(N/m
2
)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(b)
9. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 52 | Page
z/L
0.0 0.2 0.4 0.6 0.8 1.0
sN/m
2
)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
Base Fluid (j=0.00)
Nanofluid (j=0.02, S-P)
Nanofluid (j=0.02, M-P)
Nanofluid (j=0.04, S-P)
Nanofluid (j=0.04, M-P)
(c)
Re
200 300 400 500 600
sav(N/m
2
)
0.00
0.02
0.04
0.06
0.08
0.10
Base Fluid (=0.00)
Nanofluid (=0.02, S-P)
Nanofluid (=0.02, M-P)
Nanofluid (=0.04, S-P)
Nanofluid (=0.04, M-P)
(d)
Fig. 7: Local shear stress for various volume fractions at (a) Re=200 (b) Re=200 (c)Re=200 (d) different
nanoparticle volume fractions at different Re
The various average values of convective heat transfer coefficient, Nusselt number, wall shear stress
etc. are given in table 2 for different volume fractions at different Reynolds numbers.The radial distribution of
the nanoparticle volume fractions at inlet, middle and outlet section of the pipe are plotted in Fig. 8(a). The
nanoparticle volume fraction reduces near the wall as the length of the tube increases and it is lowest near the
outlet wall. The figure also shows that the volume fraction slightly increases near the axis of the pipe. Fig. 8(b)
shows the distribution of nanoparticle volume fraction for different Reynolds number at the outlet section. It
shows that the volume fraction near the wall is lowest for Re=200 and the value increases as the Reynolds
number increases to 600. So, with higher Reynolds number, the nanoparticle distribution becomes more
uniform. Both the figures are plotted for a volume fraction of 4%.
Table 2: Various average values of convective coefficient, Nusselt number and shear stress
Reynolds
number
Nanoparticle volume fraction
Convective
coefficient, hav
(W/m2
K)
Nusselt number,
Nuav
Shear stress, s
av*103
(N/m2
)
Re=200
=0.00 233.9 5.29 9.54
=0.02
Single-phase 270.4 5.32 13.34
Mixture-phase 266.9 5.25 12.87
=0.04
Single-phase 313.8 5.46 22.88
Mixture-phase 307.0 5.34 21.35
Re=400
=0.00 270.5 6.12 19.40
=0.02
Single-phase 313.3 6.16 27.12
Mixture-phase 310.3 6.11 26.46
=0.04
Single-phase 367.0 6.39 46.52
Mixture-phase 361.4 6.29 44.39
Re=600
=0.00 300.8 6.80 29.57
=0.02
Single-phase 348.4 6.85 41.33
Mixture-phase 345.4 6.79 40.57
=0.04
Single-phase 409.1 7.12 70.89
Mixture-phase 403.9 7.03 68.49
10. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 53 | Page
r/R
0.0 0.2 0.4 0.6 0.8 1.0
Volumefraction,
0.015
0.020
0.025
0.030
0.035
0.040
0.045
at inlet position
at middle position
at outlet position
(a)
r/R
0.0 0.2 0.4 0.6 0.8 1.0
Volumefraction,
0.010
0.015
0.020
0.025
0.030
0.035
0.040
0.045
Re=200
Re=400
Re=600
(b)
Fig. 8: Nanoparticle volume fraction at (a) different positions for Re=400 (b) at various Reynolds number
In Fig. 9, convective coefficient ratios from the present study are compared with the experimental
results given by Heris et al. [28]. In the figure, convective coefficient ratio of nanofluid and base fluid are
plotted against Peclet number. The nanofluid volume fraction is taken as 2.5%. The experimental convective
coefficient ratio initially decreases and then increases with the Peclet number. The convective coefficient ratio
found from single-phase study remains almost constant with Peclet number with very slight reduction with the
increase of Peclet number. The convective coefficient ratio from the mixture-phase model slightly increases
with the Peclet number. While the results from the single-phase and mixture-phase models are very close, these
values are lower than the results reported by Heris et al. [28].
Peclet number, Pe
2400 2600 2800 3000 3200 3400
hnf/hbf
1.00
1.05
1.10
1.15
1.20
1.25
1.30
Single-phase
Mixture-phase
Experimental [38]
Fig. 9: Comparison of convective heat transfer coefficient ratio of nanofluid and base fluid for different study
models.
As the numerical study model of nanofluids is still in its development, researchers have considered this
range of deviation acceptable for the nanofluid study and implemented the results in calculation of the thermal
performance of various heat exchanging devices. Based on the available nanofluid numerical models, the
current results can be considered satisfactory for numerical study of nanofluids.
V. Conclusions
In the present study, the hydrodynamic and thermal behaviors of Al2O3-water nanofluid are studied in a
circular tube by using single-phase and mixture-phase models. The following conclusions can be made from the
study of Al2O3-water nanofluid.
Convective heat transfer coefficient increases significantly with nanoparticle volume fraction for the
same Reynolds number. The increment is higher for single-phase model than the mixture-phase model
of Buongiorno [24]. The convective coefficient also increases with the Reynolds number.
Nusselt number varies slightly with the nanoparticle volume fraction for the same Reynolds number.
For lower values of volume fraction, the mixture-phase model gives slightly lower values of Nusselt
number than the base fluid, while for higher volume fraction, Nusselt number is higher than the base
11. Study of Forced Convection Heat Transfer with Single phase and mixture phase Nanofluid Model ..
DOI: 10.9790/1684-1401054455 www.iosrjournals.org 54 | Page
fluid. The single-phase study demonstrates slightly higher Nusselt number than base fluid both for
lower and higher volume fraction. Nusselt number also increases with the Reynolds number.
The wall shear stress increases with the nanoparticle volume fraction. The increment rate tends to
increase towards higher volume fraction of nanoparticle. The mixture-phase model gives lower values
of shear stress than the single-phase model.
The mixture-phase model gives the nanoparticle distribution in the flow domain. Nanoparticle concentration
tends to reduce near the wall and the reduction increases towards the outlet section. The reduced volume
fraction near the wall inevitably causes the reduced heat transfer coefficient than that found by the single-phase
model.
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