Influence Of Intake Parameters On Performance Of Proton Exchange Membrane Fuel Cell

Energy depletion and environmental pollution have become two major challenges in the world today.The emergence and development of new energy have made remarkable contributions to energy sustainable development and environmental problems.As one of new energy representatives,new energy vehicles are gradually commercialized.As a new generation of automotive engines instead of internal combustion engines,fuel cells attract a lot of domestic and foreign scholars and businessmen.However,voltage decay of proton exchange membrane fuel cell(PEMFC)continues to be a barrier that impedes PEM fuel cell performance improvement.A proper relative humidity and inlet temperature are beneficial to achieve the uniform species distribution of single cell.So relative humidity and inlet temperature are the objects of the paper as two vital parameters affecting the water management system of fuel cell.To study the effects of relative humidity and inlet temperature on voltage attenuation of vehicle fuel cell,an anode relative humidity(ARH)model is put forward.The model is based on the phenomena that there is pressure drop between channels and anode is more sensitive to flooding than the cathode.The influence of the inlet distance on inlet pressure of single cell in the stack is also considered and the effects of anode relative humidity on the performance of the cell is deduced and obtained at 40?-100?.The main content of the paper is divided into three parts:In the first part,the basic theory and a series of governing equations of PEMFC are given,and the computational model and grids of fuel cell are established.The ARH model and fluid dynamics software Fluent are used to calculate the single cell with the fastest voltage attenuation in the stack.The current density distribution,hydrogen molar concentration distribution and water mass distribution are obtained respectively at different operating temperatures and relative humidities.In the second part,the test platform of a stack composed of 10 single cells is set up.The polarization curves of single cell are obtained when operational temperatures are 60?,65?and 70?,and anode and cathode inlet pressure is 0.1MPa,and anode relative humidities are40%,55%,70%,85%and 100%,respectively.In the third part,C10(the single cell with the furthest distance from the gas inlet)is the single cell with the worst performance by comparison.Furthermore,Fluent model,ARH model and experiment results of C10 are compared and analyzed at operating temperatures60?,65?and 70?and relative humidities 55%,70%,85%and 100%,respectively.The results show that for the stack composed of 10 single cells,the voltage decay of C10is the fastest at the same operating temperature and relative humidity.At the same working temperature,the performance of C10 improves with the increase of inlet temperature.The C10 voltage is the highest and its performance is the best at 100%relative humidity,but prone to flooding.The performance of C10 can be calculated accurately by ARH model at three operating temperatures.Compared with Fluent model,ARH model accuracy improves by28%at 70?working temperature,85%relative humidity and 360 mA·cm~-22 current density.Thus,the ARH model provides a new idea for the further optimization of water management system of the stack.