Study On The Gas Liquid Two-phase Flow Mechanism And Water Distribution Characteristics Of PEMFC

Proton Exchange Membrane Fuel Cell(PEMFC)is a power generation device that directly converts chemical energy in fuel into electrical energy under the action of a catalyst.It has high energy conversion efficiency,low noise,and no pollution(products are Water),has become an excellent power source,can be used in automobiles,submarines,backup power supply and military industry,the application prospect is extremely wide.The gas-liquid two-phase flow mechanism and water distribution characteristics of proton exchange membrane fuel cells have an important influence on the performance of fuel cells.In this paper,the visualized method is used to study the distribution characteristics of cathode water in proton exchange membrane fuel cells under different operating parameters,and the effect of cathode water distribution on battery performance.The use of transparent proton exchange membrane fuel cells to study the water distribution characteristics within the fuel cell focuses on avoiding fogging in the transparent observation window and avoiding disturbances to the fuel cell system by outside temperature.Based on the visualization research of existing proton exchange membrane fuel cells,this paper improved a proton exchange membrane fuel cell.The experimental results show that the performance of the designed battery is basically the same as that of the conventional battery,and the cooling method and electricity of the designed battery The cooling mode of the stack is consistent,which is suitable for the actual operating conditions of the stack.Proper operating parameters have an important influence on the optimal performance of proton exchange membrane fuel cells.Using a transparent proton exchange membrane fuel cell,this paper studies the distribution characteristics of the cathode water of the proton exchange membrane fuel cell under different operating parameters,and the effect of the cathode water distribution on the battery performance.The results show that:(1)In the parallel flow channel,the discharge of liquid water is a Intermittent process.Only when the water droplets grow up and fuse to a critical volume,will they be discharged with the reaction gas and be discharged together with the other droplets they encounter.When the cathode gas outlet is blocked by liquid droplets,columnar flow easily occurs in the cathode flow channel,causing water flooding.(2)The content of liquid water accumulation in the cathode flow channel decreases as the operating temperature increases,but excessive operating temperature will cause the membrane to peel off,resulting in reduced battery performance.(3)Different humidification strategies have an important effect on the content of liquid accumulation in the cathode flow channel and battery performance.Too small or too high humidification temperature is not conducive to the best performance of the battery.(4)As the current density continues to increase,the cathode channel is more prone to flooding.When the initial current density is small,increasing the current density is beneficial to reduce the battery resistance,but when the current density reaches a large value,the resistance will not decrease significantly as the current density increases.