Channel two-phase flow validation and dynamics in proton exchange membrane fuel cells under water-boiling-point temperature conditions

Abstract

With the growing demand for green energy, proton exchange membrane fuel cells (PEMFCs) have developed worldwide. Increasing the operating temperature to the water-boiling-point range (100–120 ℃) can significantly enhance the heat dissipation capacity, but it induces more complex two-phase transport characteristics. In this study, a comprehensive investigation of gas/liquid two-phase flow dynamics in the channels of PEMFC operating within the water-boiling-point temperature range was conducted based on the volume of fluid (VOF) framework incorporating Lee phase-change model and species transport model, which, for the first time, was validated against the liquid flow morphology and pressure drop simultaneously. The results indicate that increasing temperature enhances the evaporation of liquid water and suppresses liquid film formation, especially within the temperature range of 80–100 ℃. As relative humidity increases, the liquid water content inside the channel decreases, with this effect being more pronounced at elevated temperatures. Moreover, a wettability-gradient structure featuring hydrophilic sidewalls and a hydrophobic top wall exhibits superior overall performance.