Optimization Design And Performance Study Of Anode Wavy Flow Field In Direct Methanol Fuel Cell

The development of human society is closely related to energy.With the rapid development of productivity,energy consumption is also increasing.However,with the global warming and the depletion of oil resources in recent years,new energy resources can solve the two problems of energy conservation and environmental protection.Direct methanol fuel cell(DMFC)has a good development prospect because of its advantages such as easy access to raw materials,high theoretical specific energy conversion efficiency,environmental protection and good safety.However,DMFC still faces some technical problems,such as methanol fuel penetration,gas management at the anode and so on.Therefore,the active DMFC single cell is the research object and the key component anode flow field plate is the research subject in this study.The purpose of this study is to explore the influence of channel structure on product management and battery performance output at anode side.Based on the traditional serpentine long straight flow field,this work puts forward the wavy flow field with the sinusoidal disturbing structure.Two-phase flow simulation based on phase field method and numerical simulation of DMFC are realized.Visualization experiment and cell performance test are also carried out.The results show that the turbulence structure can improve the fluid velocity and pressure drop in the flow field,which is conducive to improve the heat and mass transfer process.It can bu conclude that the output performance of two kinds of DMFC increased first and then decreased with the raise of methanol solution supply rate and concentration.To reveal the effects of the geometric parameters of sinusoidal turbulence structure,amplitude A and angular frequency W are further explored.With the increase of A and W,the value of velocity and flow dead zone increase.The CO2 bubble deforms seriously,and the velocity vector direction is with great difference,resulting in vortex generation and high flow resistance.With the increase of flow resistance,the volume fraction of CO2 gas and the pressure drop increase.The optimal performance is obtained with the combination of A=0.1 & W=5 in the case of sinusoidal corrugated flow fields.In order to reduce the velocity dead zone and flow resistance of sinusoidal wavy flow field,a modified flow field is proposed and manufactured.In the visualization experiment,the contour of CO2 gas column at anode side is traced,fitted and mirrored,then the modified flow channel wall function is obtained.The results show that the movement of the CO2 gas column can fit the wall well in the modified flow channel.With the high flow velocity,the modified flow field also accelerate CO2 spontaneous emission.The modified wavy flow field based on the A = 0.15 & W = 5 sinusoidal corrugated flow fields is the best anode flow pattern of DMFC in this study.