Study on the Influence of Structural Parameters of Ejectors for High-Power Fuel Cells

<div>This study focuses on a hydrogen ejector for a proton exchange membrane fuel cell (PEMFC) with a maximum power of 150 kW. Experimental tests were conducted to obtain the operating parameters of the stack under 100 kW and 150 kW conditions, which were used as simulation boundary conditions. A three-dimensional numerical model of the ejector was established and validated. Based on this model, the effects of key structural parameters—including nozzle throat radius (<i>R_nt</i>), nozzle position (NXP), mixing chamber radius (<i>R_m</i>), diffuser outlet radius (<i>R_de</i>), secondary flow inlet radius (<i>R_s</i>), suction chamber radius (<i>R_f</i>), and constant-pressure mixing chamber length (<i>L_pm</i>)—on ejector performance were systematically analyzed. The results indicate that <i>R_nt</i> and <i>R_f</i> are negatively correlated with ejector performance, while <i>R_s</i> and <i>L_pm</i> are positively correlated. In contrast, NXP, <i>R_m</i>, and <i>R_de</i> exhibit an optimal range, leading to a single-peak characteristic in ejector performance. This research provides a theoretical basis and design reference for the structural optimization of high-power fuel cell ejectors.</div>