Optimizing proton exchange membrane electrolyzers: Enhanced heat and mass transport through innovative submerged jet array design using multi-physics simulation

To address the limitations of conventional straight hollow flow channels (SHFC) in proton exchange membrane water electrolyzers (PEMWE), specifically insufficient water supply and nonuniform reactant/thermal distribution, this study proposes an innovative submerged jet flow channel (SJFC) design. A comprehensive non-isothermal two-phase flow numerical model was employed to analyze its performance. The SJFC enhances pressure-driven liquid permeation, elevating the average liquid saturation (s_l) in the anode catalyst layer (ACL) by 6.82 % while improving the distribution uniformity of liquid, temperature, and current density by 16.50 %, 51.37 %, and 5.81 %, respectively. Notably, the SJFC reduces the ACL average temperature by 8.47 K compared to SHFC. Parametric studies reveal that increasing jet inlet velocity (V_jet) from 0 to 0.3 m/s enhances liquid and temperature uniformity by 15.17 % and 22.99 %, respectively. At low current densities, the temperature uniformity is dominated by the temperature difference between jet (T_jet) and mainstream inlets (T_m,inlet). At high current densities (I_flux = 2.8 A/cm²), reducing T_jet from 353.15 K to 313.15 K results in a 62.62 % decrease in temperature uniformity index (U_T) for the counter-flow mode and a 35.18 % decrease for the co-flow mode. T_jet 〈 T_m,inlet enables uniform cooling along the flow channel and exhibits the best temperature uniformity, while T_jet 〉 T_m,inlet exacerbates localized hot spot formation, degrading temperature uniformity. Flow pattern comparisons demonstrate co-flow jets outperform counter-flow in cooling performance at low T_jet and current densities, whereas at high current densities, counter-flow mode is more superior as the largest jet mass is assigned to cool the high-temperature zone near the exit. Compared to SHFC, increasing jet column count enhances liquid and temperature uniformity by up to 7.24 % and 41.85 % due to its disturbance effect. The synergistic effect of column disturbance and jet flow enhances both liquid and temperature uniformity. These findings offer valuable insights for designing novel PEMWE architectures with optimized mass and thermal management.