Two‐Phase Flow Numerical Simulation of the Effect of Flow Channel Structure on Bubble Removal Characteristics in PEM Water Electrolysis

Proton exchange membrane (PEM) water electrolysis enables high‐efficiency production of high‐purity hydrogen. However, oxygen bubble retention within the anode‐side porous transport layer (PTL) and flow channels decreases the electrochemically active area of the catalyst layer and thereby degrades performance. To clarify how anode flow‐field design governs bubble removal from the PTL and channels, we conducted two‐dimensional two‐phase flow simulations based on the finite‐volume method. The results show that an interdigitated flow field, in which baffles partition each channel into inlet and outlet segments to force liquid water into the PTL, generates a pronounced inlet–outlet pressure differential. This pressure differential enhances bubble expulsion downstream of the baffle and increases local water saturation near the catalyst layer. Moreover, longer baffles yield larger pressure differentials and higher water saturation. Regardless of baffle length or position, bubbles are discharged downstream of the baffle. Thus, placing the baffle closer to the outlet reduces the bubble‐covered area of the catalyst layer and increases local water saturation.