Effects of pin shapes on gas-liquid transport behaviors in PEMFC cathode

Abstract

In this work, three pin-type flow field (FF) designs for a proton exchange membrane fuel cell (PEMFC) cathode with the circle, diamond, and square pins are proposed. The gas-liquid transport phenomena inside the PEMFC cathode are investigated to evaluate the water management performance of the designs. The volume of fluid model is used for the observance of the liquid water behaviors. A validated dynamic contact angle model is applied to improve the accuracy of the numerical simulation. From the results, it can be concluded that the pin shape affects greatly the emergence of liquid water from the catalyst layer, gas diffusion layer (GDL) to the FF. The study also offers insights into the airflow and liquid behaviors inside the pin-type FFs. Among the three FFs, the diamond pins remove water fastest with the lowest pressure drop. The square-pin FF also has low water mass in the computational domains but suffers from the highest pressure drop and uneven velocity, water, and pressure distributions. The circle pins have the most water content but can provide low pressure drop with the most uniform distributions. Thus, considerations for water removal ability should be taken for the pin-type FF designs regarding PEMFC performance and reliability.