The Optimization Of PEMFC Based On Genetic Algorithm

Proton Exchange Membrane Fuel Cell(PEMFC)uses hydrogen as fuel.It has the advantages of rapid response,high energy density,low noise and no pollutant.Due to these advantages,PEMFC has broad application prospects in the portable electronic equipment,automotive,distributed generation,military and aerospace fields.In this thesis,the background of fuel cell is described,and the application prospect and advantages of proton exchange membrane fuel cell as the 5th generation fuel cell are analyzed.The research status of PEMFC channel structure and operating condition optimization is introduced through literature review.Then,the mathematical model of PEM fuel cell is introduced,which includes control equations such as mass,momentum,energy and charge conservation.Then the method of genetic algorithm and numerical calculation is used to optimize the PEM fuel cell.Firstly,based on the PEM fuel cell mathematical model,a three-dimensional nonisothermal PEM fuel cell model is established by commercial software COMSOL Multiphysics.The genetic algorithm and numerical simulation are used to optimize the cross section of the flow channel to make the comprehensive performance of PEM fuel cell achieve optimum.Then,on the basis of PEM fuel cell model with the 0.02 m channel,the flow channel structure is improved,and two obstacles are inserted into the flow channel.The obstacles size is the same as the flow channel size,and the diffusion layers below the obstacles are opened for reducing the flow resistance.On this basis,the genetic algorithm is used to optimize the positions of the obstacles in the flow channel,which maximizes the net power of the PEM fuel cell.Finally,this thesis establishes a PEM fuel cell system model to optimize the PEM fuel cell operating condition.Based on the optimal operating condition,the multi-objective genetic algorithm is used to optimize the inlet height and outlet height of the flow channel so as to obtain the optimal operating condition and optimal flow channel structure of PEM fuel cell.The results show that the optimal temperature,anode pressure,cathode pressure,and operating current density are 366.15 K,4.99 atm,3.02 atm,and 0.89 A/cm2,respectively.The optimal channel structure is a wedge-shaped channel that the height gradually decreases along the flow direction.