Enhancement Effect of Heat and Mass Transfer Performance in Novel Nozzle-Like Flow Channel for Proton Exchange Membrane Fuel Cell

The flow channel plays a pivotal role in the heat and mass transfer of proton exchange membrane fuel cell (PEMFC). To optimize channel geometry, this study introduces a novel nozzle-like flow (NLF) channel and investigates the effects of transition segment (TS) width, jet segment (JS) number, and position through a PEMFC model. The results indicate that the NLF improves reactant transport rates by nearly 40%. The mass transfer rate at the interface of the porous layer in the shrinking cross section is mapped for the first time. Oxygen concentration and temperature increase with the expansion of the TS width but decrease with an increase in the JS number, whereas pressure drop and water content show the opposite trend. Additionally, optimal performance occurs at a TS width of 0.7 mm, with JS near the inlet, occupying 70% of channel length. This configuration yields net power density enhancements of 1.72% over the straight channel (SF) and 2.56% over the 0.3 mm NLF.