Maher Al-Baghdadi | University of Kufa (original) (raw)
Papers by Maher Al-Baghdadi
The vibration of structure are cusecs generation heat on the machine parts, the heat generation d... more The vibration of structure are cusecs generation heat on the machine parts, the heat generation dependent onto the natural frequency supplied on the structure and the materials types (mechanical and thermal properties). Therefore, in this paper investigation the heat generation in the beam due to vibration of beam under frequency excitation (harmonic load excitation), for the beam supported with various boundary conditions, simply supported; clamped supported; and cantilever supported beam. Also, the results included evaluated the heat generation as a function of time with different frequency applied of harmonic load, less and more than the natural frequency of beam. The heat generation due to vibration of beam with time is evaluated by analytical investigation and comparison with numerical study, by using finite element method with CFD package program. The results evaluated are shown the generation heat is decreasing with increasing the frequency of the applied harmonic load. In ad...
Measurement and prediction study of the effect of
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 2008
Considering the pollution problems and energy crisis today, investigations have been focused on l... more Considering the pollution problems and energy crisis today, investigations have been focused on lowering the concentration of toxic components in combustion products and decreasing fuel consumption by using renewable alternative fuels. The effects of ethanol addition to unleaded gasoline on the performance and pollutant emission of the spark ignition engine are established both analytically and experimentally. In the present work a quasi-dimensional model was developed to study the effect of ethanol blending on the thermodynamic cycle of the engine. The Ricardo E6/US engine has been used for verification and comparison of the results of the model with experimental tests. The results of the standard ASTM methods showed that, with increasing ethanol content, the research octane number of the blended fuels increases, while the Reid vapour pressure of the blended fuels initially increases to a maximum at 10vol% ethanol addition and then decreases. The results of the study showed that th...
Thermal management is essential in electronics, as it improves reliability and enhances performan... more Thermal management is essential in electronics, as it improves reliability and enhances performance by removing heat generated by the devices. Thermal management of handheld systems such as laptops is becoming increasingly challenging due to increasing power dissipation. The power dissipated per unit area on the laptop electronic chips is increasing while the area of the chips itself it decreasing, resulting a high heat flux that causes an increase in temperature. The increasing temperature adversely affects the performance of laptops and in many cases leads to failure through such modes as thermal fatigue and dielectric breakdown. In this work, three dimensional steady state CFD model of a laptop motherboard is presented. The model accounts for heat transfer for both natural convection and radiation to the ambient air temperature. The present CFD study allow accurate, rapid, physical modelling to make decisions on materials, components and layout beside power control feedback to ac...
Optimization CFD study of erosion in 3D elbow during transportation of crude oil contaminated with sand particles, 2018
The oil industry transport the crude oil, but with entrained solid particles. Throughout the prod... more The oil industry transport the crude oil, but with entrained solid particles. Throughout the production operations of the upstream petroleum , crude oil as well as sand particles corroded from the zones of the formation are regularly conveyed through pipes as a mixture up to the well heads and among well heads and flow stations. In this study, a three-dimensional CFD (Computational fluid dynamics) model has been developed that describes a turbulent transport of solid sand particles as well as crude oil through elbows to predict the erosions rates, where various physical aspects have been combined together including flow turbulence, particle tracking, and erosion simulation. The model has been used to investigate the different parameters that effect for crude oil and sand particles on the erosive wear rate on the pipe walls. Where, the parametric studied for crude oil are viscosity, density, velocity and temperature, also, the parametric studied for sand particles are particles size,...
... Al-Baghdadi [5] developed a multiphase three-dimensional CFD model for a planar air-breathing... more ... Al-Baghdadi [5] developed a multiphase three-dimensional CFD model for a planar air-breathing PEM fuel cell that considered both heat and mass transfer in addition to the phase-change. ... All rights reserved. 560 c O O i F M S 4 2 2 − = (17) ...
... 4. Conclusion Full three-dimensional, non-isothermal computational fluid dynamics model of a ... more ... 4. Conclusion Full three-dimensional, non-isothermal computational fluid dynamics model of a PEM fuel cell has been ... the temperature and humidity dependent material properties are utilize in the simulation for the ... Mathematical Model of Platinum Movement in PEM Fuel Cells. ...
Journal of Mechanical Engineering and Sciences, 2021
Three dimensional fluid-thermal-structure multiphysics interaction simulation model of aluminium ... more Three dimensional fluid-thermal-structure multiphysics interaction simulation model of aluminium extrusion process has been simulated and presented in this paper. This multiphysics complex geometrical engineering process is simulated effectively using computational fluid dynamics (CFD) simulation with very high accuracy, where the aluminium material is treated as a fluid that has a very high viscosity which depends on temperature and velocity. When aluminium moving, the inner friction will work as a heat source, therefore the model of the heat transfer is completely coupled together with those governing model of the fluid dynamics. Material properties come into a viscosity function that can be related to the flow stress locally depending on forming velocity and temperature. In addition, the stresses distribution in the die that introduces due to the fluid pressure and the thermal loads has been modelled by fully coupled the simulation model with the structural mechanic's analysi...
Renewable Energy eJournal, 2021
Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future th... more Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future that is sustainable, clean and environmentally friendly. PEM fuel cells are growing in importance as sources of sustainable energy and will doubtless form part of the changing program of energy resources in the future. PEM fuel cells are still undergoing intense development, and the combination of new and optimized materials, improved product development, novel architectures, more efficient transport processes, and design optimization and integration are expected to lead to major gains in performance, efficiency, reliability, manufacturability and cost-effectiveness.
The difficult experimental environment of PEM fuel cell systems has stimulated efforts to develop models that could simulate and predict multi-dimensional coupled transport of reactants, heat and charged species using computational fluid dynamic (CFD) technology. The strength of the CFD numerical approach is in providing detailed insight into the various transport mechanisms and their interaction, and in the possibility of performing parameters sensitivity analyses. The results of CFD analyses are relevant in: conceptual studies of new designs, detailed product development, troubleshooting, and redesign. CFD analysis complements testing and experimentation, by reduces the total effort required in the experiment design and data acquisition. Relevant case studies and recent progress in CFD techniques used in PEM fuel cell development have been presented and analyzed. The CFD models are shown to be able to provide a computer-aided tool for design and optimize future PEM fuel cells with much higher power density, long cell life, and lower cost.
Available at: https://ssrn.com/abstract=3908743
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2007
MDPI Encyclopedia, 2020
Two-phases, three-dimensional, Computational Fluid Dynamics (CFD) model using Reynolds Average Na... more Two-phases, three-dimensional, Computational Fluid Dynamics (CFD) model using Reynolds Average Navier Stokes (RANS) equations has been developed to simulate the air flow and the transport and dispersion of the aerosolized viral particles and fine droplets suspended in the air particles through the office. The study presents two cases involving the spreading limits and pathways of the aerosolized viral particles and fine droplets suspended in the air in a place; without and with air conditioning unit. The results showed that the use of air conditioning systems can increase the chances of spreading COVID-19 virus infection. The air-conditioning unit recirculates the same air inside a room, and this has the potential to create a virus-laden environment.
Read the full-text paper at the following link: https://encyclopedia.pub/2282
MDPI Encyclopedia, 2020
The results obtained from the design and analysis of a photovoltaic-hydrogen-PEM fuel cell (PVHPE... more The results obtained from the design and analysis of a photovoltaic-hydrogen-PEM fuel cell (PVHPEMFC) hybrid system for Najaf City in Iraq has been presented. The hybrid system consists of photovoltaic arrays coupled with an electrolyzer to produce hydrogen, a PEM fuel cell that converts chemical energy (H2) to electricity, hydrogen storage, a battery storage system, and the load. In this kind of system, all components can be connected electrically in parallel. The voltage of the PV arrays and fuel cell must be high enough to charge the battery, and the voltage of the electrolyzer must be low enough for the battery to power it during periods of low insolation. The designed system model is based on the electrical component models and variable solar radiation data depending on the location.
MDPI, 2020
Hydrogen is a very important fuel of our secure and clean energy future. Hydrogen will be the fue... more Hydrogen is a very important fuel of our secure and clean energy future. Hydrogen will be the fuel of the future and gradually it will replace all current fossil fuels. Hydrogen can be used as a fuel for vehicles, to heat homes and offices, to produce electricity, and to fuel ships and aircraft. The present work provides an overview of hydrogen as an alternative fuel, which can be used in internal combustion engines and in fuel cells.
Journal of Physics, 2020
In this research, we focus on the performance of heat sink, new configurations of the micro heat ... more In this research, we focus on the performance of heat sink, new configurations of the micro heat sink with comprises of pinned copper pieces of appropriate dimensions have been proposed. Dozens of different shapes micro heat sinks have been manufactured from brass using Laser technique. These heat sinks have been coupled individually with a simulated electronic circuit including a power transistor to freely dissipate the generated heat. Bulk temperatures of heat sink and the power transistor have been measured using a thermal camera. The results showed that, in general, the finned heat sink of either configuration augments heat transfer compared with smooth one. It is found that the maximum percentage reductions in temperature of the transistor are demonstrated with two uncommon configurations, namely the leaves-shaped fin (LSF) 9.352% and the drop-shaped fin (DSF) 9.353%. on the other hand, a staggered wavy fin (SWF) shows minimum percentage reduction in transistor temperature, 0.952%. It has been shown that through this research and by using several models of heat sink, the increase in surface area is not only the factor (major) to increase the heat transfer to the surrounding environment. This makes it possible to design fins with a smaller surface area but more heat dispersion.
Materials Science and Engineering, 2020
Graphene nanosheets were fabricated on a metal (Al) substrate by using a chemical spray method. A... more Graphene nanosheets were fabricated on a metal (Al) substrate by using a chemical spray method. Annealing process has been applied to reducing the concentration of carbon and to increase the sheet hardness. Surface morphology measured by metallurgical microscope Device Corporation, X 1600. Thermal camera was used to measure the performance of coated heat sink. The temperature was measured from the two sides, one from heat sink side, and the other one is from power transistor side. The results showed that the temperature of the transistor was decreased by about 4.3 °C in the case of heat sink coating with 80 µm layer thickness while decreased by 6.9 °C in the case of the heat sink coating with 120 µm layer thickness.
Encyclopedia, 2020
Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future th... more Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future that is sustainable, clean and environmental friendly. PEM fuel cells are growing in importance as sources of sustainable energy and will doubtless form part of the changing program of energy resources in the future. PEM fuel cells are still undergoing intense development, and the combination of new and optimized materials, improved product development, novel architectures, more efficient transport processes, and design optimization and integration are expected to lead to major gains in performance, efficiency, reliability, manufacturability and cost-effectiveness.
The difficult experimental environment of PEM fuel cell systems has stimulated efforts to develop models that could simulate and predict multi-dimensional coupled transport of reactants, heat and charged species using computational fluid dynamic (CFD) technology. The strength of the CFD numerical approach is in providing detailed insight into the various transport mechanisms and their interaction, and in the possibility of performing parameters sensitivity analyses. The results of CFD analyses are relevant in: conceptual studies of new designs, detailed product development, troubleshooting, and redesign. CFD analysis complements testing and experimentation, by reduces the total effort required in the experiment design and data acquisition. Relevant case studies and recent progress in CFD techniques used in PEM fuel cell development have been presented and analyzed. The CFD models are shown to be able to provide a computer-aided tool for design and optimize future PEM fuel cell with much higher power density, long cell life, and lower cost.
A full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped p... more A full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped proton exchange membrane (PEM) fuel cell has been developed. This comprehensive model accounts for the major transport phenomena in a PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase change mechanism of water, and potential fields. The model is shown to be able to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. In addition to the new feature of tubular-shaped geometry of PEM fuel cell, this model is used to study the effects of several material parameters on fuel cell performance. Detailed analyses of the temperature distribution inside the tubular cell under various material properties have been conducted and examined. The analysis helped identifying critical parameters and shed insight into the physical mechanisms leading to a fuel cell performance and durability under various material conditions.
The development of physically representative models that allow reliable simulation of the process... more The development of physically representative models that allow reliable simulation of the processes under realistic conditions is essential to the development and optimization of fuel cells, the introduction of cheaper materials and fabrication techniques, and the design and development of novel architectures. Full three-dimensional, multiphase, nonisothermal computational fluid dynamics models of planar and novel tubular-shaped air-breathing polymer electrolyte membrane ͑PEM͒ fuel cell have been developed. These comprehensive models account for the major transport phenomena in planar and tubular-shaped air-breathing PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields. The models are shown to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. Fully three-dimensional results of the species profiles, temperature distribution, potential distribution, and local current density distribution are presented and analyzed with a focus on the physical insight and fundamental understanding for the planar and the novel tubular geometry of air-breathing PEM fuel cells.
Owing to the energy crisis and pollution prdoblems of today, investigations have concentrated on ... more Owing to the energy crisis and pollution prdoblems of today, investigations have concentrated on decreasing fuel consumption and on lowering the concentration of toxic components in combustion products by using non-petroleum, renewable, sustainable and non-polluting fuels. While conventional energy sources such as natural gas, oil and coal are non-renewable, hydrogen and alcohol can be coupled to renewable and sustainable energy sources. The usage of a mixture of hydrogen and methane as a supplementary fuel to an alcohol-air mixture for spark ignition engines results in a considerable improvement in engine performance and in the reduction of the toxic components in exhaust gases in comparison with the conventional spark ignition gasoline engine. In tests, the gas comprising 40 per cent H 2 and 60 per cent CH 4 by volume was added to alcohol as 0, 2, 4, 6, 8, 10 and 12 per cent by mass. Operating test results for a range of compression ratio (CR) and equivalent ratio are presented. Gasoline fuel was used as a basis for comparison. The important improvement in methane addition reduced the specific fuel consumption (s.f.c.) and CO emission of alcohol engines. The performance of the engine is enhanced when relatively small amounts of hydrogen are present with methane. This improvement in performance, which is especially pronounced at operational equivalence ratios that are much leaner than the stoichiometric value, can be attributed largely to the faster and cleaner burning characteristics of hydrogen in comparison with methane or alcohol. Moreover, the addition of hydrogen decreases the s.f.c. of the engine. The possibility of an engine power quality adjustment has also been studied.
The vibration of structure are cusecs generation heat on the machine parts, the heat generation d... more The vibration of structure are cusecs generation heat on the machine parts, the heat generation dependent onto the natural frequency supplied on the structure and the materials types (mechanical and thermal properties). Therefore, in this paper investigation the heat generation in the beam due to vibration of beam under frequency excitation (harmonic load excitation), for the beam supported with various boundary conditions, simply supported; clamped supported; and cantilever supported beam. Also, the results included evaluated the heat generation as a function of time with different frequency applied of harmonic load, less and more than the natural frequency of beam. The heat generation due to vibration of beam with time is evaluated by analytical investigation and comparison with numerical study, by using finite element method with CFD package program. The results evaluated are shown the generation heat is decreasing with increasing the frequency of the applied harmonic load. In ad...
Measurement and prediction study of the effect of
Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 2008
Considering the pollution problems and energy crisis today, investigations have been focused on l... more Considering the pollution problems and energy crisis today, investigations have been focused on lowering the concentration of toxic components in combustion products and decreasing fuel consumption by using renewable alternative fuels. The effects of ethanol addition to unleaded gasoline on the performance and pollutant emission of the spark ignition engine are established both analytically and experimentally. In the present work a quasi-dimensional model was developed to study the effect of ethanol blending on the thermodynamic cycle of the engine. The Ricardo E6/US engine has been used for verification and comparison of the results of the model with experimental tests. The results of the standard ASTM methods showed that, with increasing ethanol content, the research octane number of the blended fuels increases, while the Reid vapour pressure of the blended fuels initially increases to a maximum at 10vol% ethanol addition and then decreases. The results of the study showed that th...
Thermal management is essential in electronics, as it improves reliability and enhances performan... more Thermal management is essential in electronics, as it improves reliability and enhances performance by removing heat generated by the devices. Thermal management of handheld systems such as laptops is becoming increasingly challenging due to increasing power dissipation. The power dissipated per unit area on the laptop electronic chips is increasing while the area of the chips itself it decreasing, resulting a high heat flux that causes an increase in temperature. The increasing temperature adversely affects the performance of laptops and in many cases leads to failure through such modes as thermal fatigue and dielectric breakdown. In this work, three dimensional steady state CFD model of a laptop motherboard is presented. The model accounts for heat transfer for both natural convection and radiation to the ambient air temperature. The present CFD study allow accurate, rapid, physical modelling to make decisions on materials, components and layout beside power control feedback to ac...
Optimization CFD study of erosion in 3D elbow during transportation of crude oil contaminated with sand particles, 2018
The oil industry transport the crude oil, but with entrained solid particles. Throughout the prod... more The oil industry transport the crude oil, but with entrained solid particles. Throughout the production operations of the upstream petroleum , crude oil as well as sand particles corroded from the zones of the formation are regularly conveyed through pipes as a mixture up to the well heads and among well heads and flow stations. In this study, a three-dimensional CFD (Computational fluid dynamics) model has been developed that describes a turbulent transport of solid sand particles as well as crude oil through elbows to predict the erosions rates, where various physical aspects have been combined together including flow turbulence, particle tracking, and erosion simulation. The model has been used to investigate the different parameters that effect for crude oil and sand particles on the erosive wear rate on the pipe walls. Where, the parametric studied for crude oil are viscosity, density, velocity and temperature, also, the parametric studied for sand particles are particles size,...
... Al-Baghdadi [5] developed a multiphase three-dimensional CFD model for a planar air-breathing... more ... Al-Baghdadi [5] developed a multiphase three-dimensional CFD model for a planar air-breathing PEM fuel cell that considered both heat and mass transfer in addition to the phase-change. ... All rights reserved. 560 c O O i F M S 4 2 2 − = (17) ...
... 4. Conclusion Full three-dimensional, non-isothermal computational fluid dynamics model of a ... more ... 4. Conclusion Full three-dimensional, non-isothermal computational fluid dynamics model of a PEM fuel cell has been ... the temperature and humidity dependent material properties are utilize in the simulation for the ... Mathematical Model of Platinum Movement in PEM Fuel Cells. ...
Journal of Mechanical Engineering and Sciences, 2021
Three dimensional fluid-thermal-structure multiphysics interaction simulation model of aluminium ... more Three dimensional fluid-thermal-structure multiphysics interaction simulation model of aluminium extrusion process has been simulated and presented in this paper. This multiphysics complex geometrical engineering process is simulated effectively using computational fluid dynamics (CFD) simulation with very high accuracy, where the aluminium material is treated as a fluid that has a very high viscosity which depends on temperature and velocity. When aluminium moving, the inner friction will work as a heat source, therefore the model of the heat transfer is completely coupled together with those governing model of the fluid dynamics. Material properties come into a viscosity function that can be related to the flow stress locally depending on forming velocity and temperature. In addition, the stresses distribution in the die that introduces due to the fluid pressure and the thermal loads has been modelled by fully coupled the simulation model with the structural mechanic's analysi...
Renewable Energy eJournal, 2021
Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future th... more Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future that is sustainable, clean and environmentally friendly. PEM fuel cells are growing in importance as sources of sustainable energy and will doubtless form part of the changing program of energy resources in the future. PEM fuel cells are still undergoing intense development, and the combination of new and optimized materials, improved product development, novel architectures, more efficient transport processes, and design optimization and integration are expected to lead to major gains in performance, efficiency, reliability, manufacturability and cost-effectiveness.
The difficult experimental environment of PEM fuel cell systems has stimulated efforts to develop models that could simulate and predict multi-dimensional coupled transport of reactants, heat and charged species using computational fluid dynamic (CFD) technology. The strength of the CFD numerical approach is in providing detailed insight into the various transport mechanisms and their interaction, and in the possibility of performing parameters sensitivity analyses. The results of CFD analyses are relevant in: conceptual studies of new designs, detailed product development, troubleshooting, and redesign. CFD analysis complements testing and experimentation, by reduces the total effort required in the experiment design and data acquisition. Relevant case studies and recent progress in CFD techniques used in PEM fuel cell development have been presented and analyzed. The CFD models are shown to be able to provide a computer-aided tool for design and optimize future PEM fuel cells with much higher power density, long cell life, and lower cost.
Available at: https://ssrn.com/abstract=3908743
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2007
MDPI Encyclopedia, 2020
Two-phases, three-dimensional, Computational Fluid Dynamics (CFD) model using Reynolds Average Na... more Two-phases, three-dimensional, Computational Fluid Dynamics (CFD) model using Reynolds Average Navier Stokes (RANS) equations has been developed to simulate the air flow and the transport and dispersion of the aerosolized viral particles and fine droplets suspended in the air particles through the office. The study presents two cases involving the spreading limits and pathways of the aerosolized viral particles and fine droplets suspended in the air in a place; without and with air conditioning unit. The results showed that the use of air conditioning systems can increase the chances of spreading COVID-19 virus infection. The air-conditioning unit recirculates the same air inside a room, and this has the potential to create a virus-laden environment.
Read the full-text paper at the following link: https://encyclopedia.pub/2282
MDPI Encyclopedia, 2020
The results obtained from the design and analysis of a photovoltaic-hydrogen-PEM fuel cell (PVHPE... more The results obtained from the design and analysis of a photovoltaic-hydrogen-PEM fuel cell (PVHPEMFC) hybrid system for Najaf City in Iraq has been presented. The hybrid system consists of photovoltaic arrays coupled with an electrolyzer to produce hydrogen, a PEM fuel cell that converts chemical energy (H2) to electricity, hydrogen storage, a battery storage system, and the load. In this kind of system, all components can be connected electrically in parallel. The voltage of the PV arrays and fuel cell must be high enough to charge the battery, and the voltage of the electrolyzer must be low enough for the battery to power it during periods of low insolation. The designed system model is based on the electrical component models and variable solar radiation data depending on the location.
MDPI, 2020
Hydrogen is a very important fuel of our secure and clean energy future. Hydrogen will be the fue... more Hydrogen is a very important fuel of our secure and clean energy future. Hydrogen will be the fuel of the future and gradually it will replace all current fossil fuels. Hydrogen can be used as a fuel for vehicles, to heat homes and offices, to produce electricity, and to fuel ships and aircraft. The present work provides an overview of hydrogen as an alternative fuel, which can be used in internal combustion engines and in fuel cells.
Journal of Physics, 2020
In this research, we focus on the performance of heat sink, new configurations of the micro heat ... more In this research, we focus on the performance of heat sink, new configurations of the micro heat sink with comprises of pinned copper pieces of appropriate dimensions have been proposed. Dozens of different shapes micro heat sinks have been manufactured from brass using Laser technique. These heat sinks have been coupled individually with a simulated electronic circuit including a power transistor to freely dissipate the generated heat. Bulk temperatures of heat sink and the power transistor have been measured using a thermal camera. The results showed that, in general, the finned heat sink of either configuration augments heat transfer compared with smooth one. It is found that the maximum percentage reductions in temperature of the transistor are demonstrated with two uncommon configurations, namely the leaves-shaped fin (LSF) 9.352% and the drop-shaped fin (DSF) 9.353%. on the other hand, a staggered wavy fin (SWF) shows minimum percentage reduction in transistor temperature, 0.952%. It has been shown that through this research and by using several models of heat sink, the increase in surface area is not only the factor (major) to increase the heat transfer to the surrounding environment. This makes it possible to design fins with a smaller surface area but more heat dispersion.
Materials Science and Engineering, 2020
Graphene nanosheets were fabricated on a metal (Al) substrate by using a chemical spray method. A... more Graphene nanosheets were fabricated on a metal (Al) substrate by using a chemical spray method. Annealing process has been applied to reducing the concentration of carbon and to increase the sheet hardness. Surface morphology measured by metallurgical microscope Device Corporation, X 1600. Thermal camera was used to measure the performance of coated heat sink. The temperature was measured from the two sides, one from heat sink side, and the other one is from power transistor side. The results showed that the temperature of the transistor was decreased by about 4.3 °C in the case of heat sink coating with 80 µm layer thickness while decreased by 6.9 °C in the case of the heat sink coating with 120 µm layer thickness.
Encyclopedia, 2020
Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future th... more Polymer electrolyte membrane (PEM) fuel cell system is an advanced power system for the future that is sustainable, clean and environmental friendly. PEM fuel cells are growing in importance as sources of sustainable energy and will doubtless form part of the changing program of energy resources in the future. PEM fuel cells are still undergoing intense development, and the combination of new and optimized materials, improved product development, novel architectures, more efficient transport processes, and design optimization and integration are expected to lead to major gains in performance, efficiency, reliability, manufacturability and cost-effectiveness.
The difficult experimental environment of PEM fuel cell systems has stimulated efforts to develop models that could simulate and predict multi-dimensional coupled transport of reactants, heat and charged species using computational fluid dynamic (CFD) technology. The strength of the CFD numerical approach is in providing detailed insight into the various transport mechanisms and their interaction, and in the possibility of performing parameters sensitivity analyses. The results of CFD analyses are relevant in: conceptual studies of new designs, detailed product development, troubleshooting, and redesign. CFD analysis complements testing and experimentation, by reduces the total effort required in the experiment design and data acquisition. Relevant case studies and recent progress in CFD techniques used in PEM fuel cell development have been presented and analyzed. The CFD models are shown to be able to provide a computer-aided tool for design and optimize future PEM fuel cell with much higher power density, long cell life, and lower cost.
A full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped p... more A full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped proton exchange membrane (PEM) fuel cell has been developed. This comprehensive model accounts for the major transport phenomena in a PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase change mechanism of water, and potential fields. The model is shown to be able to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. In addition to the new feature of tubular-shaped geometry of PEM fuel cell, this model is used to study the effects of several material parameters on fuel cell performance. Detailed analyses of the temperature distribution inside the tubular cell under various material properties have been conducted and examined. The analysis helped identifying critical parameters and shed insight into the physical mechanisms leading to a fuel cell performance and durability under various material conditions.
The development of physically representative models that allow reliable simulation of the process... more The development of physically representative models that allow reliable simulation of the processes under realistic conditions is essential to the development and optimization of fuel cells, the introduction of cheaper materials and fabrication techniques, and the design and development of novel architectures. Full three-dimensional, multiphase, nonisothermal computational fluid dynamics models of planar and novel tubular-shaped air-breathing polymer electrolyte membrane ͑PEM͒ fuel cell have been developed. These comprehensive models account for the major transport phenomena in planar and tubular-shaped air-breathing PEM fuel cell: convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields. The models are shown to understand the many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. Fully three-dimensional results of the species profiles, temperature distribution, potential distribution, and local current density distribution are presented and analyzed with a focus on the physical insight and fundamental understanding for the planar and the novel tubular geometry of air-breathing PEM fuel cells.
Owing to the energy crisis and pollution prdoblems of today, investigations have concentrated on ... more Owing to the energy crisis and pollution prdoblems of today, investigations have concentrated on decreasing fuel consumption and on lowering the concentration of toxic components in combustion products by using non-petroleum, renewable, sustainable and non-polluting fuels. While conventional energy sources such as natural gas, oil and coal are non-renewable, hydrogen and alcohol can be coupled to renewable and sustainable energy sources. The usage of a mixture of hydrogen and methane as a supplementary fuel to an alcohol-air mixture for spark ignition engines results in a considerable improvement in engine performance and in the reduction of the toxic components in exhaust gases in comparison with the conventional spark ignition gasoline engine. In tests, the gas comprising 40 per cent H 2 and 60 per cent CH 4 by volume was added to alcohol as 0, 2, 4, 6, 8, 10 and 12 per cent by mass. Operating test results for a range of compression ratio (CR) and equivalent ratio are presented. Gasoline fuel was used as a basis for comparison. The important improvement in methane addition reduced the specific fuel consumption (s.f.c.) and CO emission of alcohol engines. The performance of the engine is enhanced when relatively small amounts of hydrogen are present with methane. This improvement in performance, which is especially pronounced at operational equivalence ratios that are much leaner than the stoichiometric value, can be attributed largely to the faster and cleaner burning characteristics of hydrogen in comparison with methane or alcohol. Moreover, the addition of hydrogen decreases the s.f.c. of the engine. The possibility of an engine power quality adjustment has also been studied.