Fuel Cells
Amarnath Gundalabhagavan; Veeresh Babu Alur; Ganesh Babu Katam; Kshitij Bhosale
Abstract
Fuel cells have been identified as a promising technology to meet future electric power requirements. Out of various fuel cells, Proton Exchange Membrane Fuel Cells (PEMFC) has been staged up as they can operate at low temperatures and also have high power density. In this article, the flow field design ...
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Fuel cells have been identified as a promising technology to meet future electric power requirements. Out of various fuel cells, Proton Exchange Membrane Fuel Cells (PEMFC) has been staged up as they can operate at low temperatures and also have high power density. In this article, the flow field design of a Single Serpentine Flow Field (SSFF) has been modified to L-Serpentine Flow Field (LSFF) in order to reduce thermal and water management problems in PEMFC. A numerical study was conducted on 441 mm2 active area at 700C and 3 atm operating conditions, to evaluate various flow characteristics by comparing LSFF with SSFF, and it was observed that temperature and species flux distribution in LSFF enhanced significantly. The modification of the flow field yielded remarkable improvements in various aspects. These enhancements included a more uniform distribution of membrane water content, an impressive 8% increase in O2 consumption, a remarkable 22% improvement in product evacuation demonstrated by the H2O species profile, attributed to a 40% reduction in product travel distance. Additionally, a noteworthy 10% increase in power density was achieved. Despite a slight increase in pressure drop due to the additional bends and turns in the modified flow field, the impact on power density remained insignificant. These findings highlight the immense potential of the modified flow field to significantly enhance performance.
Fuel Cells
Amarnath Gundalabhagavan; Veeresh Babu Alur; Kshitij Bhosale
Abstract
Proton Exchange Membrane fuel cells (PEMFCs) are essential for the efficient operation of hydrogen-powered automobiles. To improve their performance, researchers have proposed tapered flow channels as a possible solution. However, determining the optimal value for the tapering has not been explored in ...
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Proton Exchange Membrane fuel cells (PEMFCs) are essential for the efficient operation of hydrogen-powered automobiles. To improve their performance, researchers have proposed tapered flow channels as a possible solution. However, determining the optimal value for the tapering has not been explored in depth. In this study, a numerical investigation was conducted to optimize the tapering of tapered serpentine channels in PEMFCs. The results show that while anode channel tapering has a negligible effect on performance, cathode channel tapering has a significant impact. The study found that a flow channel geometry with an inlet of 0.8 mm and an outlet of 0.2 mm, with a gradual decrease in cross-section, resulted in the maximum net output, with a 10.64% increase in net power output at 0.7 V. Additionally, the improved water management performance was observed. Based on these findings, tapering flow channels only on the cathode side could be utilized as an optimal design for achieving higher performance. Overall, this study is significant as it provides valuable insights into optimizing the performance of PEMFCs, which can enhance their efficiency and utilization in hydrogen-powered vehicles. It highlights the importance of investigating the effects of flow channel geometry on performance and can guide future research in this area to improve the efficiency of PEMFCs.
Fuel Cells
M. Rostami; A. H. Farajollahi; F. Bagherpor; V. Sfandiyar
Abstract
Polymer electrolyte membrane fuel cells (PEMFCs) produce high power density efficiently and in a pollution-free way. Therefore, it is employed in UAVs. Flow fields play key role in the performance of PEMFC-powered UAVs. In this study, a novel flow field named modified combined was introduced and investigated ...
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Polymer electrolyte membrane fuel cells (PEMFCs) produce high power density efficiently and in a pollution-free way. Therefore, it is employed in UAVs. Flow fields play key role in the performance of PEMFC-powered UAVs. In this study, a novel flow field named modified combined was introduced and investigated by a three-dimensional and two-phase PEMFC model. In the flow field main channels are tapered aiming to reinforce the performance. The study consists of two steps. In the first stage, modified combined was compared with parallel, serpentine, interdigitated, and combined. The results showed that in the modified combined compared with simple combined, pressure drop decreased 22.6%. Modified combined demonstrated suitable oxygen distribution and appropriate management and the specific power of modified combined is the highest value among all flow fields. Finally, the effect of atmospheric conditions on the performance of the PEMFC with modified combined flow field was studied and two equations were presented to predict the performance at 0.4V and 0.7V at the different altitudes of flight. The findings unveiled the point that in the cruise phase of the flight, low voltage is more suitable for PEMFC-driven UAV with modified combined flow field. All in all, modified combined flow field and low voltage are recommended to be utilized in PEMFCs as propulsion system of UAVs.
Fuel Cells
M. Rostami; A.H. Farajollahi; M. Marefati; R. Fili; F. Bagherpor
Abstract
The propulsion system of an Unmanned Aerial Vehicle (UAV) plays an essential role in its performance, stability and flight endurance. In this study, two types of propulsion systems for UAV (differentiated based on fuel type) are studied to determine their characteristics and advantages. These proposed ...
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The propulsion system of an Unmanned Aerial Vehicle (UAV) plays an essential role in its performance, stability and flight endurance. In this study, two types of propulsion systems for UAV (differentiated based on fuel type) are studied to determine their characteristics and advantages. These proposed propulsion systems are using a solid oxide fuel cell (SOFC) to generate the heat required for the operation of the turbine and generating thrust. To achieve the best operating condition, a multi-objective Non-Dominated Sorting Genetic Algorithm (NSGA-II) in MATLAB is used to decide key design parameters. For reaching the best conditions where the acceptable thrust is accompanied by reasonable flight duration, the TOPSIS decision-making method was considered. Results indicated that the efficiency and generated power of the propulsion system will increase by higher flight altitude or compressor pressure ratio. Also, due to the recirculation of fuel in the SOFC’s anode, the higher efficiency is observed in comparison when hydrogen is used; since anode-recirculation causes higher fuel utilization. The optimization result shows that the efficiency and fuel consumption for the hydrogen-fueled system is 48.7% and 0.0024g/s, respectively, and 67.9% and 0.0066kg/s for methane-fueled engine. It was also found that, maximum efficiency for both hydrogen- and methane-fueled systems are available with the stack temperature of 1025 K; however maximum thrust for these systems is at the stack temperature of 1075 K. In addition, increasing fuel rate of the SOFC power unit helps the process of generating extra power and thrust for UAVs.
Fuel Cells
M. Beigzadeh; F. Pourfayaz; S.M. Pourkiaei
Abstract
The use of green buildings is increasing these days and many activities in order to improve the efficiency of this type of constructions have been done by the advancement of technology. Fuel cells are one of equipment which have been used to generate power and heat for residential buildings in recent ...
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The use of green buildings is increasing these days and many activities in order to improve the efficiency of this type of constructions have been done by the advancement of technology. Fuel cells are one of equipment which have been used to generate power and heat for residential buildings in recent years. For this purpose, a building in a cold region has been studied. In this study, the fuel of the fuel cell is provided from renewable fuel reforming, which is fermentation of waste and wastewater. First, a SOFC modeling has been carried out which is fed by biogas from a building waste. The modeling results of renewable-fuel fuel cell of this building have showed that 72% of electricity and 13% of the required heating could be provided using its wastes. All in all, by using biogas which has been produced from building waste, most required power and a part of required hot water could be provided and the environmental pollution is reduced by utilizing waste and trash. This will utilize all waste of the building for biofuels production and also provides major of the electricity and heating demand of the building.
Fuel Cells
Haleh Sadeghi; I. Mirzaee; Sh. Khalilarya; N. Ahmadi
Abstract
In present research, a three-dimensional, single phase proton-exchange membrane fuel cell has been simulated numerically. The governing equations have been solved using finite volume scheme and the obtained results have been validated against famous published data which showed proper conformity. The ...
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In present research, a three-dimensional, single phase proton-exchange membrane fuel cell has been simulated numerically. The governing equations have been solved using finite volume scheme and the obtained results have been validated against famous published data which showed proper conformity. The basic target is an investigation of the gas channel shape effect on cell performance and mass transport phenomenon. First, the besides walls of gas channels have been converted from straight condition to sinusoidal form with two different steps and in continue, the membrane electrode assembly has been bended in four states, but the gas channel cross section area has been kept 1 mm2. The results revealed that, the spiral models because of curved construction, prepare the long pathway for incoming gases and also much mass diffusion to the reaction area. So for model M1, the produced current density for V=0.6 [V], increased about 7.5% and consequently more oxygen and hydrogen consumed. The pressure drop of spiral models has been studied and results showed that the base model has the less pressure drop but model M2 because of higher performance and nearly same pressure drop can be a best choice for user. Also, for new bended models, the best choice is a model with δ=0.4, which has produced more current density, while its reaction area is about 19.64 mm2 larger than the conventional model with δ=0.