This document presents a numerical simulation of a solar air heater using pin fins attached to the absorber plate. ANSYS 14 software was used to model the system and optimize fin geometry. Pin fins can increase thermal efficiency by up to 99% compared to a solar air heater without fins. Staggered fin arrangements provided higher efficiency than inline arrangements, with up to a 13% increase in efficiency observed. The study analyzed the effects of varying mass flow rate, fin height, thickness and arrangement on thermal performance.
Numerical Investigation of Solar Air Heater Duct using Broken‘S’ Shaped Ribs ...ijtsrd
The solar air heater has an important place among solar heat collectors. It can be used as sub systems in many systems meant for the utilization of solar energy. Possible applications of solar air heaters are drying or curing of agricultural products, space heating for comfort regeneration of dehumidifying agents, seasoning of timber, curing of industrial products such as plastics. When air at high temperature is required the design of a heater becomes complicated and very costly. As far as the ultimate application for heating air to maintain a comfortable environment is concerned, the solar air heater is the most logical choice. In general solar heaters are quite suitable for low and moderate temperatures application as their design is simple. These solar air heaters have low heat transfer efficiency which can be improved using geometrical modifications like optimizing duct geometry or adding artificial roughness. The use of artificial roughness on the underside of the absorber plate is an effective and economic way to improve the thermal performance of a solar air heater. Several experimental investigations, involving different types of roughness elements, have been carried out to improve the heat transfer from the absorber plate to air flowing in solar air heaters. In this paper the CFD analysis on heat transfer and friction in rectangular ducts roughened with broken‘S’ shaped ribs has been presented. The relative gap width g e is varied from 0.5 to 2.5 and other parameter are constant. The effects of gap width g e on Nusselt number, friction factor and thermo hydraulic performance parameter have been discussed and results compared with smooth duct under similar conditions. It is found that the maximum heat transfer and friction characteristic at a relative gap width of 1. Ankit Sahu | C. S. Koli "Numerical Investigation of Solar Air Heater Duct using Broken‘S’ Shaped Ribs Roughness on Absorber Plate" 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/ijtsrd33610.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/33610/numerical-investigation-of-solar-air-heater-duct-using-broken-%E2%80%98s%E2%80%99-shaped-ribs-roughness-on-absorber-plate/ankit-sahu
In compact heat exchangers, thermal resistance is generally dominant on the air-side and may
account for 80% or more of the total thermal resistance. The air-side heat transfer surface area is 8 to
10 times larger than the water-side. Any improvement in the heat transfer on air-side therefore
improves the overall performance of the heat exchanger. Due to the high thermal resistance on the
air-side, the optimization of such fins is essential to increase the performance of the heat exchangers
which results in thermal systems enhancement. This helps to reduce CO2 emissions through a
reduction of mass and fuel consumption.
Optimization of louvered fin geometry in such heat exchangers is essential to increase the
heat transfer performance and reduce weight, packaging, and cost requirements. In this study deals
with Computational Fluid Dynamics (CFD) studies of the interactions between the air flow and
louvered fins which equipped the automotive heat exchangers is carried out. 3D numerical
simulation results is obtained by using the ANSYS Fluent 14.0 code and compared with
experimental data. Finally the effect of louver angle and louver pitch geometrical parameters, on
overall thermal hydraulic performances of louvered fins is studied.
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.
experimental investigation of heat transfer intensification of pin fins under...INFOGAIN PUBLICATION
Recent development era in technology has huge requirement of high performance lightweight, and compact heat transfer equipment. To accomplish this demand fins are widely used as effective elements for heat transfer enhancement. One of the commonly used heat exchanger fins is the pin fin which offers an economical and trouble free solution in many situations. This is more important in cooling of air conditioning equipment, thermal power plants, gas turbine blade, aerospace industry, combustion chamber liners, and biomedical devices, electrical and electronic component. Therefore now a day’s industries are utilizing thermal system with pin fins and analyse the various influencing parameters on performance of pin fin of different geometry under force convection. The turbulence occurred due to these techniques are good enough to enhance heat transfer rate. This article is focused on comprehensive review of work carried out in this technology.
Analysis of Natural Convention Heat Transfer Enhancement in Finned Tube Heat ...journal ijrtem
ABSTRACT: Most of the engineering problems require high performance heat transfer components with progressively less weight, volumes, accommodating shapes and costs. Air cooled heat exchangers are subjected to air on outer side of heat exchanger surface on in heat recovery systems like economizers gases are subjected on one side of tube surface. On air or gas side heat transfer coefficient is less. Extended surface (fins) are one of the next exchanging devices that are employed extensively to increase heat transfer rates from tubular heat exchangers. The rate of heat transfer depends on the surface area of fin available for exchanging the heat transfer rate from the primary surface of cylindrical shape. Present study focuses on enhancement of heat transfer by using both circular and elliptical type of fins. The present paper attempts to examine trend of heat transfer coefficient experimentally and by using CFD software for various types of elliptical fins with i) varying elliptical ratio, ii) changing orientation of mounting of heat exchanger tube with elliptical fins, iii) varying spacing or fin density. KEY WORDS: Natural convection, Heat transfer enhancements, Elliptical fin, Fin orientation, Fin density.
Thermo Hydraulic Performance of a Curved Solar Air Heater with Different Shap...ijtsrd
In contrast to the flat plate SAH design, curved designs of solar air heater ducts show substantial improvement in thermal characteristics, with the former showing a slight decrease in hydraulic efficiency. The creation of secondary vortices resulting in the mixing flow is demonstrated by curved SAH due to the centrifugal effect. In addition, the creation of dean vortices increases the rate of heat transfer in curved SAH. In flat plate SAH, these results are absent. In this present work, a three dimensional CFD analysis was carried out in a Curved duct of a solar air heater with a upper roughened wall with down configuration ribs having shape of half triangular, full triangular, and semi circular to investigate the heat transfer and flow behavior. The simulation programme ANSYS 17.0 was used for study of the heat transfer physiognomies of a curved duct of a solar air heater. The curved solar air heater with triangular rib roughness on the absorber plate has been found to yield improved results relative to the half triangular and semi circular rib and can thus be used to increase the heat transfer. The maximum enhancement in Nusselt number is found to be in triangular shaped ribs, which is 1.112 times that of half triangular corresponding to at a Reynolds number of 15,000 for the investigated range of parameters. Satish Sahu | Prof. Animesh Singhai "Thermo-Hydraulic Performance of a Curved Solar Air Heater with Different Shaped down Turbulators using CFD" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-2 , February 2021, URL: https://www.ijtsrd.com/papers/ijtsrd38546.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/38546/thermohydraulic-performance-of-a-curved-solar-air-heater-with-different-shaped-down-turbulators-using-cfd/satish-sahu
Numerical Investigation of Solar Air Heater Duct using Broken‘S’ Shaped Ribs ...ijtsrd
The solar air heater has an important place among solar heat collectors. It can be used as sub systems in many systems meant for the utilization of solar energy. Possible applications of solar air heaters are drying or curing of agricultural products, space heating for comfort regeneration of dehumidifying agents, seasoning of timber, curing of industrial products such as plastics. When air at high temperature is required the design of a heater becomes complicated and very costly. As far as the ultimate application for heating air to maintain a comfortable environment is concerned, the solar air heater is the most logical choice. In general solar heaters are quite suitable for low and moderate temperatures application as their design is simple. These solar air heaters have low heat transfer efficiency which can be improved using geometrical modifications like optimizing duct geometry or adding artificial roughness. The use of artificial roughness on the underside of the absorber plate is an effective and economic way to improve the thermal performance of a solar air heater. Several experimental investigations, involving different types of roughness elements, have been carried out to improve the heat transfer from the absorber plate to air flowing in solar air heaters. In this paper the CFD analysis on heat transfer and friction in rectangular ducts roughened with broken‘S’ shaped ribs has been presented. The relative gap width g e is varied from 0.5 to 2.5 and other parameter are constant. The effects of gap width g e on Nusselt number, friction factor and thermo hydraulic performance parameter have been discussed and results compared with smooth duct under similar conditions. It is found that the maximum heat transfer and friction characteristic at a relative gap width of 1. Ankit Sahu | C. S. Koli "Numerical Investigation of Solar Air Heater Duct using Broken‘S’ Shaped Ribs Roughness on Absorber Plate" 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/ijtsrd33610.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/33610/numerical-investigation-of-solar-air-heater-duct-using-broken-%E2%80%98s%E2%80%99-shaped-ribs-roughness-on-absorber-plate/ankit-sahu
In compact heat exchangers, thermal resistance is generally dominant on the air-side and may
account for 80% or more of the total thermal resistance. The air-side heat transfer surface area is 8 to
10 times larger than the water-side. Any improvement in the heat transfer on air-side therefore
improves the overall performance of the heat exchanger. Due to the high thermal resistance on the
air-side, the optimization of such fins is essential to increase the performance of the heat exchangers
which results in thermal systems enhancement. This helps to reduce CO2 emissions through a
reduction of mass and fuel consumption.
Optimization of louvered fin geometry in such heat exchangers is essential to increase the
heat transfer performance and reduce weight, packaging, and cost requirements. In this study deals
with Computational Fluid Dynamics (CFD) studies of the interactions between the air flow and
louvered fins which equipped the automotive heat exchangers is carried out. 3D numerical
simulation results is obtained by using the ANSYS Fluent 14.0 code and compared with
experimental data. Finally the effect of louver angle and louver pitch geometrical parameters, on
overall thermal hydraulic performances of louvered fins is studied.
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.
experimental investigation of heat transfer intensification of pin fins under...INFOGAIN PUBLICATION
Recent development era in technology has huge requirement of high performance lightweight, and compact heat transfer equipment. To accomplish this demand fins are widely used as effective elements for heat transfer enhancement. One of the commonly used heat exchanger fins is the pin fin which offers an economical and trouble free solution in many situations. This is more important in cooling of air conditioning equipment, thermal power plants, gas turbine blade, aerospace industry, combustion chamber liners, and biomedical devices, electrical and electronic component. Therefore now a day’s industries are utilizing thermal system with pin fins and analyse the various influencing parameters on performance of pin fin of different geometry under force convection. The turbulence occurred due to these techniques are good enough to enhance heat transfer rate. This article is focused on comprehensive review of work carried out in this technology.
Analysis of Natural Convention Heat Transfer Enhancement in Finned Tube Heat ...journal ijrtem
ABSTRACT: Most of the engineering problems require high performance heat transfer components with progressively less weight, volumes, accommodating shapes and costs. Air cooled heat exchangers are subjected to air on outer side of heat exchanger surface on in heat recovery systems like economizers gases are subjected on one side of tube surface. On air or gas side heat transfer coefficient is less. Extended surface (fins) are one of the next exchanging devices that are employed extensively to increase heat transfer rates from tubular heat exchangers. The rate of heat transfer depends on the surface area of fin available for exchanging the heat transfer rate from the primary surface of cylindrical shape. Present study focuses on enhancement of heat transfer by using both circular and elliptical type of fins. The present paper attempts to examine trend of heat transfer coefficient experimentally and by using CFD software for various types of elliptical fins with i) varying elliptical ratio, ii) changing orientation of mounting of heat exchanger tube with elliptical fins, iii) varying spacing or fin density. KEY WORDS: Natural convection, Heat transfer enhancements, Elliptical fin, Fin orientation, Fin density.
Thermo Hydraulic Performance of a Curved Solar Air Heater with Different Shap...ijtsrd
In contrast to the flat plate SAH design, curved designs of solar air heater ducts show substantial improvement in thermal characteristics, with the former showing a slight decrease in hydraulic efficiency. The creation of secondary vortices resulting in the mixing flow is demonstrated by curved SAH due to the centrifugal effect. In addition, the creation of dean vortices increases the rate of heat transfer in curved SAH. In flat plate SAH, these results are absent. In this present work, a three dimensional CFD analysis was carried out in a Curved duct of a solar air heater with a upper roughened wall with down configuration ribs having shape of half triangular, full triangular, and semi circular to investigate the heat transfer and flow behavior. The simulation programme ANSYS 17.0 was used for study of the heat transfer physiognomies of a curved duct of a solar air heater. The curved solar air heater with triangular rib roughness on the absorber plate has been found to yield improved results relative to the half triangular and semi circular rib and can thus be used to increase the heat transfer. The maximum enhancement in Nusselt number is found to be in triangular shaped ribs, which is 1.112 times that of half triangular corresponding to at a Reynolds number of 15,000 for the investigated range of parameters. Satish Sahu | Prof. Animesh Singhai "Thermo-Hydraulic Performance of a Curved Solar Air Heater with Different Shaped down Turbulators using CFD" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-5 | Issue-2 , February 2021, URL: https://www.ijtsrd.com/papers/ijtsrd38546.pdf Paper Url: https://www.ijtsrd.com/engineering/mechanical-engineering/38546/thermohydraulic-performance-of-a-curved-solar-air-heater-with-different-shaped-down-turbulators-using-cfd/satish-sahu
CFD Base Performance Evaluation of Earth-Air Tube Heat Exchanger for Natural ...journal ijrtem
ABSTRACT: The earths inside temperature is commonly higher than the outside air temperature in winter and lower in summer so it can makes the use of the earth convenient as warm source or cold sink respectively. Earth air heat exchanger can contributes to reduce in energy consumption. Numbers of research have been carried out on Computational Fluid Dynamics analysis of EATHE systems and still it requires optimum redevelopment. In the present work a 3D CAD model was developed for CFD analysis of earth air tube heat exchanger (EATHE) system. The obtained simulated results were compared with experimental results obtained from experimental setup installed at Bhopal situated in Central India. The temperature of earth at a certain depth about 2 m to 3 m of ground remains nearly constant throughout the year this constant temperature is called the undisturbed temperature of earth. The performance evolution was carried out to check the effect of pipe length, air flow velocity, depth of buried pipe and pipe diameter of EATHE system for summer cooling. The result shows that this system is more convenient only for summer cooling and not suitable for winter heating. KEYWORDS: CAD Modeling, Earth‐Air Tube Heat Exchanger, CFD Analysis, etc
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
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.
The results show that, with proper selection of physical parameters, significant heat transfer
enhancements and pressure drop reductions can be achieved simultaneously with porous pin fins and
the overall heat transfer performances in porous pin fin channels are much better than those in
traditional solid pin fin channels. The effects of pore density are significant. As PPI increases, the
pressure drops and heat fluxes in porous pin fin channels increase while the overall heat transfer
efficiencies decrease and the maximal overall heat transfer efficiencies are obtained at PPI 20.
Furthermore, the effects of pin fin form are also remarkable. With the same physical parameters, the
overall heat transfer efficiencies in the long elliptic porous pin fin channels are the highest while they
are the lowest in the short elliptic porous pin fin channels
Performance evaluations of two pass solar air heater using 60â° inclinedv-sh...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
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
A Detailed Review on Artificial Roughness Geometries for Optimizing Thermo-Hy...IJMER
It is well known fact that the heat transfer coefficient between the absorber surface of solar air collector & flowing fluid i.e. air can be improved by providing artificial roughness geometry on heat transfer surface (absorber surface).In this way the Thermal efficiency is increased. But at the same time due to roughness geometry pumping power of solar air collector in increased due to fictional losses in duct. So it necessary to examine the shape, size & flow pattern of various roughness elements to get maximum efficiency with minimum frictional losses. Therefore the selection of roughness geometry has to be based on the parameter that takes into account both Thermal & Hydraulic (friction) performance i.e. Thermo-hydraulic Performance of Solar air collector. Number of roughness elements has been investigated on heat transfer & friction characteristics of solar air collectors. In this paper, reviews of various artificial roughness elements used as passive heat transfer techniques, in order to improve Thermo-hydraulic performance of solar air collectors is reviewed & presented. Correlations developed by various researchers with the help of experimental results for heat transfer & friction factor for solar air collector by taking different roughness geometries are given & these correlations are useful to predict the Thermo-hydraulic performance of solar air collector having roughened ducts. The objective of this paper is also the awareness of effect of various types’ roughness geometries on heat
HEAT TRANSFER AUGMENTATION IN A PLATE-FIN HEAT EXCHANGER: A REVIEWIAEME Publication
The improvement of the performance of heat exchangers with gas as the working fluid becomes particularly important due to the high thermal resistance offered by gases in general. In order to compensate for the poor heat transfer properties of gases, the surface area density of plate heat exchangers can be increased by making use of the secondary fins such as, off-set fins, triangular fins, wavy fins, louvered fins etc. In addition, a promising technique for the enhancement of heat transfer is the use of longitudinal vortex generators. The longitudinal vortices are produced due to the pressure difference generated between the front and back surface of the vortex generator.
Performance Analysis of a Shell Tube Condenser for a Model Organic Rankine Cy...IJERA Editor
The global energy demand increases with the economic growth and population rise. Most electrical power is currently generated by conventional methods from fossil fuels. Despite the high energy demand, the conventional energy resources such as fossil fuels have been declining. In addition to this harmful combustion byproducts are resulting global warming. However, the increase of environmental concerns and energy crisis can be minimized by sustainable utilization of the low to medium temperature heat resources. The Organic Rankine Cycle power plant is a very effective option for utilization of low grade heat sources for power generation. Heat exchangers are the main components of the Organic Rankine Cycle power plant which receives heat energy from the heat source to evaporate and condense the low boiling temperature organic working fluid which in turn drives the turbine to generate power. This paper presents a simplified approach to the design, fabrication and performance assessment of a shell tube heat exchanger designed for condenser in a model Organic Rankine Cycle geothermal power plant. The design involved sizing of heat exchanger (condenser) using the LMTD method based on an expected heat transfer rate. The heat exchanger of the model power plant was tested in which hot water simulated geothermal brine. The results of the experiment indicated that the heat exchanger is thermally suitable for the condenser of the model power plant.
CFD Base Performance Evaluation of Earth-Air Tube Heat Exchanger for Natural ...journal ijrtem
ABSTRACT: The earths inside temperature is commonly higher than the outside air temperature in winter and lower in summer so it can makes the use of the earth convenient as warm source or cold sink respectively. Earth air heat exchanger can contributes to reduce in energy consumption. Numbers of research have been carried out on Computational Fluid Dynamics analysis of EATHE systems and still it requires optimum redevelopment. In the present work a 3D CAD model was developed for CFD analysis of earth air tube heat exchanger (EATHE) system. The obtained simulated results were compared with experimental results obtained from experimental setup installed at Bhopal situated in Central India. The temperature of earth at a certain depth about 2 m to 3 m of ground remains nearly constant throughout the year this constant temperature is called the undisturbed temperature of earth. The performance evolution was carried out to check the effect of pipe length, air flow velocity, depth of buried pipe and pipe diameter of EATHE system for summer cooling. The result shows that this system is more convenient only for summer cooling and not suitable for winter heating. KEYWORDS: CAD Modeling, Earth‐Air Tube Heat Exchanger, CFD Analysis, etc
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
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.
The results show that, with proper selection of physical parameters, significant heat transfer
enhancements and pressure drop reductions can be achieved simultaneously with porous pin fins and
the overall heat transfer performances in porous pin fin channels are much better than those in
traditional solid pin fin channels. The effects of pore density are significant. As PPI increases, the
pressure drops and heat fluxes in porous pin fin channels increase while the overall heat transfer
efficiencies decrease and the maximal overall heat transfer efficiencies are obtained at PPI 20.
Furthermore, the effects of pin fin form are also remarkable. With the same physical parameters, the
overall heat transfer efficiencies in the long elliptic porous pin fin channels are the highest while they
are the lowest in the short elliptic porous pin fin channels
Performance evaluations of two pass solar air heater using 60â° inclinedv-sh...inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
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
A Detailed Review on Artificial Roughness Geometries for Optimizing Thermo-Hy...IJMER
It is well known fact that the heat transfer coefficient between the absorber surface of solar air collector & flowing fluid i.e. air can be improved by providing artificial roughness geometry on heat transfer surface (absorber surface).In this way the Thermal efficiency is increased. But at the same time due to roughness geometry pumping power of solar air collector in increased due to fictional losses in duct. So it necessary to examine the shape, size & flow pattern of various roughness elements to get maximum efficiency with minimum frictional losses. Therefore the selection of roughness geometry has to be based on the parameter that takes into account both Thermal & Hydraulic (friction) performance i.e. Thermo-hydraulic Performance of Solar air collector. Number of roughness elements has been investigated on heat transfer & friction characteristics of solar air collectors. In this paper, reviews of various artificial roughness elements used as passive heat transfer techniques, in order to improve Thermo-hydraulic performance of solar air collectors is reviewed & presented. Correlations developed by various researchers with the help of experimental results for heat transfer & friction factor for solar air collector by taking different roughness geometries are given & these correlations are useful to predict the Thermo-hydraulic performance of solar air collector having roughened ducts. The objective of this paper is also the awareness of effect of various types’ roughness geometries on heat
HEAT TRANSFER AUGMENTATION IN A PLATE-FIN HEAT EXCHANGER: A REVIEWIAEME Publication
The improvement of the performance of heat exchangers with gas as the working fluid becomes particularly important due to the high thermal resistance offered by gases in general. In order to compensate for the poor heat transfer properties of gases, the surface area density of plate heat exchangers can be increased by making use of the secondary fins such as, off-set fins, triangular fins, wavy fins, louvered fins etc. In addition, a promising technique for the enhancement of heat transfer is the use of longitudinal vortex generators. The longitudinal vortices are produced due to the pressure difference generated between the front and back surface of the vortex generator.
Performance Analysis of a Shell Tube Condenser for a Model Organic Rankine Cy...IJERA Editor
The global energy demand increases with the economic growth and population rise. Most electrical power is currently generated by conventional methods from fossil fuels. Despite the high energy demand, the conventional energy resources such as fossil fuels have been declining. In addition to this harmful combustion byproducts are resulting global warming. However, the increase of environmental concerns and energy crisis can be minimized by sustainable utilization of the low to medium temperature heat resources. The Organic Rankine Cycle power plant is a very effective option for utilization of low grade heat sources for power generation. Heat exchangers are the main components of the Organic Rankine Cycle power plant which receives heat energy from the heat source to evaporate and condense the low boiling temperature organic working fluid which in turn drives the turbine to generate power. This paper presents a simplified approach to the design, fabrication and performance assessment of a shell tube heat exchanger designed for condenser in a model Organic Rankine Cycle geothermal power plant. The design involved sizing of heat exchanger (condenser) using the LMTD method based on an expected heat transfer rate. The heat exchanger of the model power plant was tested in which hot water simulated geothermal brine. The results of the experiment indicated that the heat exchanger is thermally suitable for the condenser of the model power plant.
NUMERICAL INVESTIGATION OF AUTOMOTIVE RADIATOR LOUVERED FIN COMPACT HEAT EXCH...IAEME Publication
In compact heat exchangers, thermal resistance is generally dominant on the air-side and may account for 80% or more of the total thermal resistance. The air-side heat transfer surface area is 8 to 10 times larger than the water-side. Any improvement in the heat transfer on air-side therefore
improves the overall performance of the heat exchanger. Due to the high thermal resistance on the air-side, the optimization of such fins is essential to increase the performance of the heat exchangers which results in thermal systems enhancement. This helps to reduce CO2 emissions through a
reduction of mass and fuel consumption.
“International Journal on Emerging Technologies” (ISSN NO. Online: 2249-3255) a peer-reviewed and free open access journal, aims to provide the complete and reliable source of information on current developments in the fields of all sciences. The emphasis will be on publishing quality articles rapidly and openly available to researchers worldwide. Manuscripts submitted to “International Journal on Emerging Technologies” must be original work that has not been published or under consideration for publication elsewhere. All submissions must be written in English. Manuscripts should be typed double space on A4 size paper using font size 12 and preferably not more than 30 pages in length inclusive of tables, figures and illustrations. All submissions will be peer reviewed. The scope of “International Journal on Emerging Technologies” covers all aspects of Electrical, Electronics, Computer IT, Instrumentation, Mechanical, Civil engineering, Physics, Chemistry, Mathematics, Environmental Sciences and Agriculture Sciences, “International Journal on Emerging Technologies” is biannual journal. Papers solicited for “International Journal on Emerging Technologies” can be in the form of survey/tutorial, regular papers, brief papers, case studied and technical correspondence. This journal provides a national and international forum for rapid publication of work describing theoretical as well as practical aspects.
Heat Transfer Analysis of a Plate Heat Exchanger with a Combination of Ribs a...ijtsrd
The advancements and improvements in all heat transfer equipment’s are primarily intended to save energy and reduce project capital investment expenses energy or material . A better heat exchanger is one that can transfer a high heat rate while using a low pumping power and at a cheap cost. Passive heat transfer enhancement techniques have various benefits over other heat transfer enhancement techniques, including low cost, ease of fabrication, and installation. Rib turbulators can enhance heat transmission significantly, but they generally come at a considerable cost in terms of pressure loss. Dimple techniques have lately gained popularity because to their ability to promote heat transmission while imposing a minor pressure penalty. When dimple surfaces are mixed with nanofluids, some studies have seen increased heat transmission, but the key concern is an increase in the systems friction factor, which is also regulated within acceptable ranges. The thermal characteristics of a heat exchanger with a combination of dimple ribs were evaluated using a 3 dimensional numerical 3 D simulation. The subject of this study is the handling of air flow velocity through the channel, which was changed from 3.97 to 5.80 m s. The simulation programme ANSYS 19.2 was used to investigate the heat transfer physiognomies of a heat exchanger managing a combination of dimple ribs. The numerical findings revealed that the combination of dimple ribs greatly improved heat transmission over the dimple alone. In comparison, the average Nusselt number of a channel with dimpled Plate is 4.28 percent more than that of a channel with dimpled ribs. Prof. Pushparaj Singh | Navin Kumar "Heat Transfer Analysis of a Plate Heat Exchanger with a Combination of Ribs and Dimples using CFD" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-6 | Issue-4 , June 2022, URL: https://www.ijtsrd.com/papers/ijtsrd49887.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/49887/heat-transfer-analysis-of-a-plate-heat-exchanger-with-a-combination-of-ribs-and-dimples-using-cfd/prof-pushparaj-singh
A Review Paper on Fin Efficiency Enhancementijtsrd
From the previous couple of decades no of endeavours have made by scientists to upgrade the rate of heat transfer with the utilization of fins by differing number of parameters. The parameters like fin geometries, fin spacing, temperature dissemination, height, length have been explored in this paper. The paper gives some short audits about the methods for improving the rate of heat transfer by use of fins. Principle thought process of the paper is to give some concise information about the efficiency enhancements that can be made in fins to improve heat transfer rate. Naveen Kumar | Udit Singhal "A Review Paper on Fin Efficiency Enhancement" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-1 , December 2019, URL: https://www.ijtsrd.com/papers/ijtsrd29543.pdf Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/29543/a-review-paper-on-fin-efficiency-enhancement/naveen-kumar
First law thermal performance improvement of vapour compression refrigeration...editorijrei
In past time, HFC refrigerants were used in refrigeration process and they were having a global warming potential at high level. Now, as time change, and due to the modern techniques are coming into existence with the help of them the refrigeration process become more efficient and safe as compare to previous in atmospheric prospective.
The nanotechnologies used in present time in the vapor compression refrigeration system. The nano refrigerant is nothing but the combined form of nano particle with the refrigerant. The nano refrigerant can be formed by two ways (1) by mixing nano particles with refrigerant in gaseous form, (2) by mixing nano particles to lubricant. We will combine different nano particles such as copper, Al2O3having the same diameter and same volume fraction with the R718 in the secondary circuit of evaporator and to study the nature of thermo-physical properties in refrigeration process which improves the first law performance of vapour compression refrigeration system The nano particles like AL2O3, CuO and TiO2 mixed in R718 and used in secondary circuit of evaporator gives better around 95% more improvements in heat transfer coefficient which improves 11.8% to 19.05% first law thermal performances as presented in this paper
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
Helically Coiled Tube with Different Geometry and Curvature Ratio on Convecti...AM Publications
A helically coil-tube heat exchanger is generally applied in industry applications due to its compact structure, larger heat transfer area and higher heat transfer capability. Several studies from literature have also indicated that heat transfer rate in helically coiled tube are superior to straight tube due to complex flow pattern exist inside helical pipe. The concept behind compact heat exchanger is to decrease size and increase heat load which is the typical feature of modern helical tube heat exchanger. While the heat transfer characteristics of helical coil heat exchangers are available in the literature, This paper elaborates a brief review on different curvature ratio and geometry of tubes in heat transfer through heat exchangers.
[1] ijrei vol 1, issue-2Community analysis of key pests associated with menth...editorijrei
An extensive survey was carried out during 2013 for the real situation in the crop to study the plant pathogenic fungus, bacteria and nematodes associated with Japanese Mint Mentha arvensis var piperascense growing fields. Soil and root samples were collected from 24 Mentha fields represents 15 different locations (villages) Akhtarpur, Tiwaripur, Shuklapur, Katia, Oripur, Ghuripur, Padariya and Dafara. Out of 120 soil samples, 16 soil samples were found infected with Fusarium oxysporum and 27 soil samples with Alternaria spp. 36 samples have the plant parasitic nematodes population. Results revealed that the maximum disease prevalence (DP) of Fusarium oxysporum was recorded at Shuklapur (27%), while the minimum disease prevalence was recorded at Ghuripur (3.4%). Alternaria spp. was more prevalent at Tiwaripur (42%) while root-knot nematode (Meloidogyne incognita) incidence was maximum at Katia (43%). The plant extracts were not so promising for inhibition of pathogenic fungi of Mentha crop.
Vibration analysis of a cantilever beam with crack depth and crack location e...editorijrei
Alloy beams and beam like elements are principal constituents of many structures and widely used in high speed machinery, aircraft and light weight structures. Crack is a damage that often occurs on members of structures and may cause serious failures of structures. In this research the natural frequency of a cracked cantilever beam is investigated by finite element method by using of ANSYS program with different crack depth and location effect. The beam material studied is aluminum alloy, titanium alloy, copper alloy and magnesium alloy. A comparison is made between these alloys and conclude optimized result between them. The increase of the beam length result in a decrease in the natural frequencies of the composite beam and also shows that an increase of the depth of cracks lead to a decrease in the value of natural frequencies.
Analysis of vortex formation around a circular cylinder at low Reynolds numbereditorijrei
Vortex shedding is one of the most interesting phenomenon in turbulent flow. This phenomenon was first studied by Strouhal. In this paper, the analysis of vortex shedding around a 2 dimensional circular cylinder with Reynolds No of 200, 500, and 1000 with different angle of attack 00, 50, and 100 has been studied. In this simulation an implicit pressure-based finite volume method and second order implicit scheme is used. Flow has been studied with the help of Navier-Stokes and continuity equations. The pressure, drag coefficients and vortex shedding for different Reynolds numbers and different angle of attack were computed and compared with other numerical result that show good agreement.
Vibration analysis and response characteristics of a half car model subjected...editorijrei
The displacement response of different masses of half car model. The analysis has been done for different car models also to see the dynamic response of the driver body coupled with the seat of a vehicle. It has been assumed the driver body is rigidly coupled with seat of the vehicle. The vehicle has been modeled for two D.O.F, in two D.O.F Half car model two motion (Pitch and Bounce) have been considered. The response of the vehicle has been obtained for different velocities and different amplitudes sinusoidal bump excitation.
Numerical investigation of fluid flow and aerodynamic performance on a 2D NAC...editorijrei
The performance of an aircraft wing mostly depends on the aerodynamic characteristics i.e. lift force, drag force, pressure distribution, the ratio of lift to drag etc. In this paper, the influence of aerodynamic performance on two dimensional NACA 4412 airfoil is investigated. The computational method consist of steady state, incompressible, finite volume method, spalart-allmaras turbulence model. The flow has been studied with the help of Navier-Stroke and continuity equations. Numerical simulations were performed at Reynolds number (1x106, 2x106, 3x106, and 4x106) at a different angle of attack (00, 30,60, and 90). The results give the satisfactory measure of confidence of fidelity of the simulation. Aerodynamic forces are calculated with different Reynolds number and angle of attack, after analyzing the data it is found that the higher lift coefficient was obtain in Re-4x106 at an angle of attack 9 whereas low drag coefficient obtained in Re-1x106 at AOA-0.
Analysis of calorimetric measurement bismuth and tin system editorijrei
Lead-free soldering alloys with low melting point suitable for use in soldering joints are very essential. Use of lead as a solder is considered dangerous for the environment due to the huge number of printed circuit board and electronic devices, pipe joints etc. needed to be recycled from dumps.
In this work the metallic samples were prepared from Bi in the mass range from 0.75gm. Samples of Sn were dropped into the bath of pure Bi by using an automatic dropping device. System required 40min time interval after every sample of dropped. Calorimetric measurements was done at temperature 830K. The Integral and partial enthalpy of mixing was calculated at this temperatures. The Integral enthalpy of mixing in Bi- Sn system at 830K is endothermic in nature throughout the composition and its maximum value at Xsn = 0.6, is 1005.9061 respectively.
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.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
2. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
8
amount of the energy requirements of many countries.
The production oil reached a maximum around 1985
and now is declining. Present indications are that most
of the reserves of oil and natural gas are likely to be
consumed in other 40 year.
As oil and natural gas become scarcer, a greater
emphasis will fall on coal. It is likely that the
production of coal will touch a maximum somewhere
between the years 2030 and 2060 and that 80 per cent
of the amount available could consumed by 2250 AD.
1.1 Introduction to solar air heater with recycle
It is a particular type of solar air heater in which some
amount of heated air from the outlet of air heater is
continuously circulated through recycle channel and it is
re-mixed to the fresh air at the inlet. Due to recycling the
temperature and flow rate of air get increased at inlet. The
ratio of rate at which air is circulated through recycle
channel to the rates at which air is collected at outlet is
called recycle ratio or reflux ratio (R). A schematic
diagram of recycle type solar air heater is shown in fig.1.
It was pointed out that applications of the recycle effect in
the design and operation of the equipment with external or
internal reflux can effectively enhance the effect on heat-
and mass-transfer, leading to improved performance [5-8].
Actually, there are two conflict effects of recycle operation.
One is the desirable effect of increasing fluid velocity,
resulting in enhancement of convective heat- or mass-
transfer, while the other is the undesirable effect of
decreasing the driving force (temperature or concentration
difference) due to remixing. It was found that the increase
in convective heat- or mass-transfer by increasing the
reflux ratio can generally compensate for the decrease of
driving force, leading to improved performance.
Figure: 1 Schematic diagram of solar air heater with
recycle
2. Literature Review
Norris and Spofford [9], derived first basic heat transfer
and flow-friction data for pin fin surfaces. The experiments
were carried out with the aim of the derivation of basic
parameters of forced convection heat transfer for
continuous, corrugated, strip and pin fins. By use of the
perimeter as the length scale, they could approximately
represent the heat transfer data with a single curve for a
single plane, single cylinder, various strip fins and pin fins.
Norris and Spofford included in their tests an in-line pin fin
arrangement with pin diameters of 0.5 mm and 1 mm and
a pin length of ~ 19 mm.
Kays [10], performed probably the most extensive study of
pin fins as elements for heat transfer enhancement. He
presented test data for four in-line pin arrangements and
one staggered arrangement. It was demonstrated that
owing to a high area to perimeter ratio, pin fins provide one
method for obtaining very high heat transfer coefficients
while at the same time maintaining high fin effectiveness.
He concluded that despite high friction factors of pin fin
surfaces, it is possible to design heat exchangers that are
competitive, from volume and weight points of view, with
heat exchangers having continuous or louvered fins.
Theoclitus[11], performed a limited parametric study of
pin fins with an in-line arrangement. He investigated nine
different geometries of in-line pin fins with circular cross-
section with length to diameter ratios in the range4 ≤ l/d ≤
12. Further, he investigated the acoustic and vibrational
characteristics of the flow over the pins and concluded that
these phenomena are basically influenced by the fluid
velocity and heat exchanger configuration. In general, the
average heat transfer rates reported by Theocritus were
lower for short than for longer cylinders.
Sparrow and Ramsey [12], reported excellent
experimental work on the influence of tip clearance for a
staggered wall-attached array of cylinders. They obtained
data on heat transfer coefficients by applying the analogy
between heat and mass transfer via the naphthalene
sublimation technique. They found that the heat transfer
coefficient increases moderately as the length of the
cylinder increases and the tip clearance between the pin
and the shroud decreases. On the other hand, the array
pressure drop increases markedly with increasing cylinder
length. This behavior was explained with inter-cylinder
velocities for short pins which are less than the mean
velocity, whereas for taller cylinders the inter-cylinder
velocities tend to approach the mean value.
VanFossen [13], investigated the heat transfer from short
pin fin arrays taking into account the heat transfer from the
pin fin surfaces and from end walls. He found that heat
transfer from short pins with a length to diameter ratio l/d
= 2 and 0.5 was lower than those of long pins based on the
available data for long pins. Further he found that heat
transfer from the pin surface was 35% higher than from the
end walls.
Sparrow and Molki [14], investigated the effect of
missing a pin in the array on the heat transfer and pressure
drop characteristics for the flow over pin fins.
Metzger et al. [15], in their investigations of short pin fin
arrays with l/d = 1, found the pin surface heat transfer
coefficients to be approximately twice as large as those
3. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
9
acting on the end walls. The main objective of the
investigations was the influence of the array orientation
with respect to the mean flow direction on the heat transfer
rates and the associated pressure losses for circular and
oblong pin fin arrays. It was reported that with circular pin
fins rotated two-thirds of the way towards a in-line
orientation from a staggered orientation, a 9% increase in
heat transfer and an18% decrease in pressure loss were
observed. For the oblong pins there was 20 % increase in
heat transfer compared with the circular pin fin arrays but
this increase was offset by an approximately 100%
increase in pressure loss.
Babus’Haq et al. [16] studied the influences of the pin fin
distance and the pin fin material on thermal performance
of the inline and staggered pin fin assembly. They
determined the optimal fin distance in the stream wise
direction for a uniform span wise distance and noted that
the optimal spacing increases as the thermal conductivity
of the pin fin material increases. Further, they noted that
the overall pressure drop for all tested configurations
increases steadily with increasing mean inlet velocity and
with decreasing uniform pin fin spacing
3. Numerical simulation and analysis
Numerical Simulation in a crude sense is the method of
predicting the output of a proposed system or an existing
system without conducting experiment on it. A
commercially available software ANSYS-14.0 (FLUENT)
is used to investigate the thermal performance of solar air
heater with pin fins attached on absorber plate.
3.1 Steps for Simulation in Computer Aided Engineering
Software (CAE)
Simulation in CAE software contains three main steps and
various sub-steps
(a) Pre-Processing
This is the first step of CFD simulation process,
which helps in describing the geometry in the best
possible manner. It has some sub-steps as follows
Generation of geometry
Grid generation
Physics model selection
Material properties
Boundary condition
Initial condition
(b) Solver
Once the problem physics has been identified, fluid
material properties, flow physics model, and boundary
conditions are set to solve using computer through
following processes
Solver selection
Residual target
Initialization
(c) Post Processing
The next step after getting the results is to analyze the results
with different methods like contour plots, stream lines,
vector plots etc.
3.1.1 Geometry Generation
The collector consists of one glass cover (2 mm thickness),
a black absorber plate (0.6 x 0.6 m), 196 square shape pin
fins of aluminum attached on absorber plate, one channel
of dimensions (0.6 x 0.6x 0.05 m) for downward flow of
air and an insulated recycle channel of same dimensions as
shown in fig. 2. The air flows in passage between glass
cover and absorber plate and some amounts of hot air from
outlet is re-circulated through recycle channel and it is re-
mixed with cold air at inlet of SAH.
(a)
(b)
Figure: 2 (a) Recycle type solar air heater with pin fins
attached (b) Schematic diagram of solar air heater
4. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
10
Figure: 3 Computational domain of SAH
4. Governing Equations
The governing transport equations in 3D Cartesian
coordinates for the fluid flow, heat and mass transfer are
given below
Continuity equation
𝜕𝑢
𝜕𝑥
+
𝜕𝑣
𝜕𝑦
+
𝜕𝑤
𝜕𝑧
= 0 (1)
X- Momentum equation
𝑢
𝜕𝑢
𝜕𝑥
+ 𝑣
𝜕𝑢
𝜕𝑦
+ 𝑤
𝜕𝑢
𝜕𝑧
= −
1
𝜌
𝜕𝑝
𝜕𝑥
+ 𝜈 ⌊
𝜕2 𝑢
𝜕𝑥2 +
𝜕2 𝑢
𝜕𝑦2 +
𝜕2 𝑢
𝜕𝑧2⌋ (2)
Y- Momentum equation
𝑢
𝜕𝑣
𝜕𝑥
+ 𝑣
𝜕𝑣
𝜕𝑦
+ 𝑤
𝜕𝑣
𝜕𝑧
= −
1
𝜌
𝜕𝑝
𝜕𝑦
+ 𝜈 ⌊
𝜕2 𝑣
𝜕𝑥2 +
𝜕2 𝑣
𝜕𝑦2 +
𝜕2 𝑣
𝜕𝑧2⌋ (3)
Z Momentum equation
𝑢
𝜕𝑤
𝜕𝑥
+ 𝑣
𝜕𝑤
𝜕𝑦
+ 𝑤
𝜕𝑤
𝜕𝑧
= −
1
𝜌
𝜕𝑝
𝜕𝑧
+ 𝜈 ⌊
𝜕2 𝑤
𝜕𝑥2 +
𝜕2 𝑤
𝜕𝑦2 +
𝜕2 𝑤
𝜕𝑧2 ⌋ (4)
Energy equation
𝑢
𝜕𝑇
𝜕𝑥
+ 𝑣
𝜕𝑇
𝜕𝑦
+ 𝑤
𝜕𝑇
𝜕𝑧
= 𝛼 ⌊
𝜕2 𝑢
𝜕𝑥2 +
𝜕2 𝑢
𝜕𝑦2 +
𝜕2 𝑢
𝜕𝑧2⌋ (5)
In the above equations, u, v and w are the velocity
components in x, y and z directions, p and T are the
pressure and temperature of the flowing air.
Transport equation for the Realizable k-ε model.
Turbulent kinetic energy k equation
𝜕
𝜕𝑡
(𝜌𝜀) +
𝜕
𝜕𝑥 𝑗
(𝜌𝑘𝑢𝑗) =
𝜕
𝜕𝑥 𝑗
⌊(𝜇 +
𝜇 𝑡
𝜎 𝑘
)
𝜕𝑘
𝜕𝑥 𝑗
⌋ + 𝐺 𝑘 + 𝐺 𝑏 −
𝜌𝜀 − 𝑌𝑀+𝑆 𝑘 (6)
Rate of energy dissipation ε equation,
𝜕
𝜕𝑡
(𝜌𝜀) +
𝜕
𝜕𝑥 𝑗
(𝜌𝜀𝑢𝑗) =
𝜕
𝜕𝑥 𝑗
[(𝜇 +
𝜇 𝑡
𝜎 𝜀
)
𝜕𝜀
𝜕
] + 𝜌𝐶1 𝑆𝜀 −
𝜌𝐶2
𝜀2
𝑘+√𝜈𝜀
+ 𝐶1𝜀
𝜀
𝑘
𝑐3𝜀 𝐺 𝑏 + 𝑆𝜀 (7)
Where,𝑐1 = 𝑚𝑎𝑥 [0.43,
𝜂
𝜂+5
], 𝜂 = 𝑆
𝑘
𝜀
, 𝑠 = √2𝑠𝑖,𝑗 𝑠𝑖,𝑗 (8)
In these equations,𝐺 𝑘represents the generation of
turbulence kinetic energy due to themean velocity
gradients,𝐺 𝑏is the turbulence kinetic energy generated due
to buoyancy,𝑌𝑀 represents the contribution of the
fluctuating dilatation in compressible turbulence to the
overall dissipation rate,𝐶2 and𝐶1𝜀 are the constant, 𝜎𝑘and
𝜎𝜀are theturbulent Prandtl numbers for𝑘 and 𝜀,
respectively. 𝑆 𝑘 and𝑆𝜀 are user-defined source terms.
The eddy viscosity is computed from
𝜇 𝑡 = 𝜌𝐶𝜇
𝑘2
𝜀
(9)
The model constants are 𝐶1𝜀 = 1.44, 𝐶2 = 1.9, 𝜎𝜀 = 1.2 (10)
Table: 1 properties of materials
5. Boundary Conditions
5.1 Boundary Conditions without Recycling
(a) Inlet boundary: At the inlet of SAH uniform mass flow
rates are used and the direction is normal to the
opening at inlet, mass flow rates along the x-axis are
taken as 0.005, 0.01, 0.015 and .02 kg/s. Turbulence
parameters at the inlet are defined using turbulence
intensity (assuming 5%) and inlet characteristic length
(hydraulic diameter) as 0.0923 m. Inlet air temperature
is taken as 288 K
(b) Both the radiation and convection boundary
conditions are applied to the glass cover. Convective
heat transfer coefficient (hw) for ambient air flowing
over the outside surface of the glass cover depends
primarily on the wind velocity.
hw= 5.7 + 3.8 V (11)
Ambient temperature for radiation from top of glass is
taken as 283 K.
Material
Density
(kg/ m3
)
Specific
heat
J/kg K
Thermal
Conductivity
(W/m 2
K)
Refractive
index
Air 1.225 1006 0.0242 --
Glass 2600 840 1.05 1.5
Aluminum 2719 871 202.4 --
5. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
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(c) Absorber plate is assumed to be insulated at bottom
side.
(d) Sides and bottom losses are assumed to be zero.
(e) Boundary condition at outlet is taken as pressure
outlet.
5.2 Boundary condition with recycle operation
(a) Inlet boundry conditions
Figure: 4 schematic diagram of solar air heater
operating with recycle
In order to determine the mixed air temperature 𝑇𝑓,𝑖
𝑜
because of recycling, let take an energy balance at the inlet
with the inlet temperature 𝑇𝑓,𝑖 as the reference temperature.
𝑚̇ 𝐶 𝑝(𝑇𝑓,𝑖 − 𝑇𝑓,𝑖) + 𝑚̇ 𝑅𝐶 𝑝(𝑇𝑓,𝑜 − 𝑇𝑓,𝑖) = 𝑚̇ (1 +
𝑅)𝐶 𝑝(𝑇𝑓,𝑖
𝑜
− 𝑇𝑓,𝑖) (12)
𝑇𝑓,𝑖
𝑜
= 𝑇𝑓,𝑖 + [
𝑅
1+𝑅
] (𝑇𝑓,𝑜 − 𝑇𝑓,𝑖) (13)
Hence in case of recycling uniform air flow rate at inlet is
taken as 𝑚̇ (1 + 𝑅) instead of 𝑚̇ and inlet air temperature
is given by equation 3.16.
b) Recycle channel is assumed to be perfectly insulated.
While all other boundary conditions are same as without
recycling.
5.3 Solver selection
There are two technologies are available in ANSYS Fluent
to solve any problem one is pressure based solver and
another is density based solver here in this study pressure
based solver is used for Solar Air Heater simulation, Two
algorithms also exist under the pressure-based solver, a
segregated algorithm and a coupled algorithm, for present
work coupled algorithm is used in which the momentum
equations and the pressure-based continuity equation are
solved in a coupled manner. Also the coupled algorithm
significantly improves the convergence speed over the
segregated algorithm. The coupled algorithm solves the
momentum and pressure-based continuity equations
together. The full implicit coupling is achieved through an
implicit discretization of pressure gradient terms in the
momentum equations, and an implicit discretization of the
face mass flux, including the Rhie-Chow pressure
dissipation terms.
5.4 Initialization
Before we start our calculations or patch initial values for
selected variables in selected cells we must initialize the
flow field in the entire domain. The Solution Initialization
Task Page allows us to set initial values for the flow
variables and initialize the solution using these values.
Initialization will result in the volume fraction, X, Y, and
Z velocities, and pressure being patched in the domain. The
volume fraction will be patched in the domain based on the
free surface level of the selected zone from the Compute
from list. The velocities in the domain will be patched
assuming the constant value provided for the velocity
magnitude in the selected zone. There are two types of
initialization method.
Hybrid Initialization
Standard Initialization
5.5 Hybrid Initialization
It is a collection of boundary interpolation methods, where
variables, such as temperature, turbulence, species
fractions, volume fractions, etc., are automatically patched
based on domain averaged values or a particular
interpolation recipe. We have to proceed through following
three steps in using hybrid initialization.
Number of Iterations uses a default value of 10. This is the
number of iterations that will be performed while solving
the Laplace equations to initialize the velocity and
pressure. In general we do not need to change the number
of iterations. However, for complex and highly curved
geometries, if the default number of iterations is not
enough to reach the convergence tolerance of 1e-06 and the
flow fields are not to our liking, then we have to increase
the number of iterations and re-initialize the flow.
5.6 Explicit Under-Relaxation
Factor uses a default value of 1. This value will be used
while solving the Laplace equation to initialize the velocity
and pressure. In general, we do not need to change the
explicit under-relaxation factor. However, for some cases,
where the scalar residuals are oscillating and showing
difficulty reaching the convergence tolerance of 1e-06, we
have to re-initialize the flow by reducing the under-
relaxation factor. We may also want to increase the number
of iterations to produce a smooth initialization field for the
velocity and pressure.
Reference Frame is set to Relative to Cell Zone by default.
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If our problem involves moving reference frames or sliding
meshes, indicate whether the initial velocities are absolute
velocities or velocities relative to the motion of each cell
zone by selecting absolute or Relative to Cell Zone. If no
zone motion occurs in the problem, the two options are
equivalent. If the solution in most of our domain is rotating,
using the relative option may be better than using the
absolute option.
5.7 Standard Initialization
Allows us to define values for flow variables and initialize
the flow field to these values. We can compute the values
from information in a specified zone, enter them manually,
or have the solver compute average values based on all
zones. We can also indicate whether the specified values
for velocities are absolute or relative to the velocity in each
cell zone. The steps for standard initialization are as
follows
Compute from is a drop-down list of zones; the default
values for applicable variables will be computed from
information contained in the zone that we select from this
list. The computation will occur when we select the
required zone, and the variable values will be displayed in
Initial Values. We can also choose the all zones item in this
list to compute average values based on all zones.
Reference Frame indicates whether the initial velocities are
absolute velocities (Absolute) or velocities relative to the
motion of each cell zone (Relative to Cell Zone). This
selection is necessary only if our problem involves moving
reference frames or sliding meshes. If there is no zone
motion, both options are equivalent.
Initial Values displays the initial values of applicable
variables. We can use Compute from to compute values
from a particular zone, or we can enter values directly.
Initialize initializes the entire flow field to the values listed.
Reset resets the fields to their “saved” values.
Standard initialization is used for simulation of solar air
heater. The values are computed from inlet and fluid is
used as a reference frame.
5.8 Calculation for collector efficiency
By the application of above processes we get outlet air
temperature, mean fluid temperature, glass cover
temperature and mean absorber plate temperature. After
getting the outlet air temperature we predict the thermal
efficiency of solar collector by the use of following
equations.
𝜂 =
𝑈𝑠𝑒𝑓𝑢𝑙 𝑔𝑎𝑖𝑛 𝑜𝑓 𝑒𝑛𝑒𝑟𝑔𝑦 𝑐𝑎𝑟𝑟𝑖𝑒𝑑 𝑎𝑤𝑎𝑦 𝑏𝑦 𝑎𝑖𝑟
𝑇𝑜𝑡𝑎𝑙 𝑠𝑜𝑙𝑎𝑟 𝑟𝑎𝑑𝑖𝑎𝑡𝑖𝑜𝑛 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡
=
𝑚̇ 𝐶 𝑝(𝑇 𝑓,𝑜−𝑇 𝑓,𝑖)
𝐼 𝑜 𝐴 𝑐
(14)
and for recycling,
𝜂 =
𝑚̇ (1+𝑅)𝐶 𝑝(𝑇 𝑓,𝑜−𝑇𝑓,𝑖
𝑜
)
𝐼 𝑜 𝐴 𝑐
(15)
Where mixed air flow temperature 𝑇𝑓.𝑖
𝑜
at beginning of the
upper channel, can be calculated by using equation (13).
6. Results and discussions
Four inlet mass flow rates of 0.005, 0.01, 0.015, and 0.02
kg/s corresponding to the Re number to be 850, 1670, 2500
and 3400 are adopted to analyze the thermal performance
of a flat plate solar air heater with internal pin fins attached
by operating with external recycle. At the absorber plate,
square pin fins are arranged in line and staggered ways.
Both staggered and in-line cases are investigated and the
results are compared and analyzed for the following design
and operating conditions:
L = B = 0.6 m; Ac = LB = 0.36 m2
; τ = 0.90; αp = 0.95;
εg = εp = 0.95; Io = 830 w/m2
; Tf,i = 288 K; V = 1 m/s; Ta
= 283 K; σ = 5.67 x 10-8
w/m2
K4
; N=196.
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As thickness of fins increases, the air temperature is firstly
increased due to increase in exposed surface area for
convective heat transfer but simultaneously causes for
decrease in plate area available for absorbing the sun
radiation. Hence after reaching a particular optimum value
of fin thickness second effect is dominated and thereafter
temperature of air get decreased continuously as indicated
from table 2.
6.1 Velocity vectors, temperature contours and stream
lines
Velocity vectors, temperature contours and stream lines
were generated in ANSYS-14(FLUENT) software and are
shown in fig. 5-12.
Figure: 5 Velocity vector 1 generated in ANSYS-14
Figure: 6 Velocity vector 2 generated in ANSYS-14
Figure: 7 Temperature Contour 1 (a) generated in ANSYS-14
9. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
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Figure: 8 Temperature Contour 1 (b) generated in ANSYS-14
Figure: 9 Temperature Contour 1 (c) generated in ANSYS-14
Figure: 10 Temperature Contour 2 at z-x plane, from y=20 mm, for m=0.005 kg/s
10. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
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Figure: 11 Temperature Contour 2 at z-x plane, from y=20 mm, for m=0.01 kg/s
Figure: 12 Temperature Contour 2 at z-x plane, from y=20 mm, for m=0.02 kg/s
For lower air flow rates mean temperature of absorber plate
and fins is higher than that of high flow rates, as indicated
from figs. 7-9. The temperature variations at z-x plane and
from a distance y = 20 mm are shown in fig 10-12. Since
for low air flow rates (0.005 kg/s) energy carried away by
fluid is lower compare to higher flow rates (0.02 kg/s).
That’s why the mean temperature of absorber plate and fins
is highest for air flow rate of 0.005 kg/s and lowest for flow
rate of 0.02 kg/s, as shown in fig 10-12.
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Figure: 13 Comparison Temperature variations at z-x plan for m=0.005 kg/s (in-line arrangement)
Figure: 14 Comparison Temperature variations at z-x plan for m=0.005 kg/s (staggered arrangement)
12. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
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Figure: 15 Comparison temperature variations at z-x plan for m=0.001 kg/s (in-line arrangement)
Figure: 16 Comparison temperature variations at z-x plan for m=0.001 kg/s (staggered arrangement)
Fig. 13 &14 show the temperature variations for in-line
arrangement and staggered arrangement respectively with
mass flow rate of 0.005 kg/s. And fig. 15 & 16 show the
temperature variations for in-line arrangement and
staggered arrangement respectively with mass flow rate of
0.01 kg/s. since energy transfer to the air is more for
staggered arrangement that’s why mean temperature of fins
seems lower than in-line arrangement. Since at lower air
flow rates, air has more time of contact with absorber plate
and fins that is why at lower mass flow rates temperatures
of air are found to be higher than temperatures of air at
higher flow rates.
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Figure: 17 Stream lines for m=0.01 kg/s (in-line arrangements)
Figure: 18 Stream lines for m=0.01 kg/s (staggered arrangements)
By the observation of stream lines for staggered and in-line
arrangement it has been found that swirls generation in
case of staggered fins are more than in-line arrangement.
Hence the heat transfer to the air will be higher in case of
staggered fins.
4.3 Effect of recycling on thermal performance of solar
collector
To investigate the effect of external recycle with fin fins
attached on absorber plate, 196 square shape pin fins of 10
mm thickness (sides) and height 25 mm each were attached
on absorber plate and reflux ratio was varied from 0 to 5
for mass flow rates of 0.01, 0.015 and 0.02 kg/s and its
effects on collector efficiency and outlet air temperature
are determined.
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Table: 3 Improvement of collector performance with recycling, for t=10 mm and h=25 mm.
m R Tpm (K) Tf,o(K) η(%) I(%)
0.01
0 337.09 301.66 45.60 0.00
1 324.12 304.04 53.95 18.31
2 318.93
305.03 57.29
25.63
3 316.25
305.51 58.89
29.14
4 315.38
305.68 59.49
30.46
5 315.02
305.75 59.78
31.09
0.015
0 327.12 298.31 52.01 0.00
1 317.12
299.87 59.61
14.63
2 313.56 300.45 62.81 20.78
3 311.89
300.74 64.21
23.48
4 310.65 300.9 65.01 25.03
5 310.32 300.96 65.41 25.78
0.02
0 321.95 296.37 56.30 0.00
1 313.65 297.46 63.72 13.14
2 310.15
297.92 66.7
18.47
3 308.48
298.12 68.02
20.08
4 307.40 298.23 68.71 22.04
5 306.73 298.3 69.22 22.94
The improvement in collector efficiency I by operating
with recycling is best illustrated by calculating the
percentage increase in collector efficiency based on
operating without recycling.
The device performance of pin fined attached single pass
solar air heater with external recycle was investigated
numerically. The advantages of pin fined attached solar air
heater are to create turbulence intensity and enlarge the
heat transfer area, and hence, the heat transfer efficiency is
enhanced. The improvement in collector efficiencies of
Single- pass type solar air heaters with pin fins attached
operating at same air flow rate, based on a single pass
device without fins of the same working dimension, and
were calculated and the results are presented in Table 3.
The collector efficiencies of both device, η and ηo, increase
with air flow rate. The height and the thickness of the pin
fin were varied from 0 to 45 mm and 0 to 30 mm
respectively and results obtained are presented in Tables 2.
The results show that to get optimum efficiency, the ratio
of h/t should be high with lower mass flow rate, and should
be comparatively low with higher mass flow rates. The
optimum ratio of h/t for196 fins on absorber plate have
been found as 4.5, 1.5-2, 1-1.2 with mass flow rates of
0.005, 0.01 and 0.02 kg/s respectively.
A comparison has been made between recycle type solar
air heater with pin fins attached and longitudinal fins
attached for almost same total cross section area of the fins,
results show that efficiency of collector with pin fins
15. Radha Kant et al/ International journal of research in engineering and innovation (IJREI), vol 1, issue 2 (2017), 7-21
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attached is 30% and 23% more than that of SAH with
longitudinal fins attached for reflux ratio of 0 and 1
respectively, with mass flow rate 0.01 kg/s, and 22% and
19% more with mass flow rate of 0.02 kg/s for reflux ratio
(R) of 0 and 1 respectively.
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