Effect of Structural Parameters and Operational Characteristic Analysis on Ejector Used in Proton Exchange Membrane Fuel Cell

A hydrogen ejector for PEMFC system is designed based on thermodynamic theory with considering the influence of water vapor. A CFD model is built in order to optimize the geometric parameters, comprehensively considering performance of different operating conditions. Moreover, effect of structural parameters and operating conditions on PEMFC ejector performance was studied using single-factor and multi-factor analysis methods. The single-factors analysis results show that the nozzle throat diameter, nozzle divergent angle (A), nozzle throat length (B), nozzle exit position (C), mixing tube diameter (D), mixing tube length (E) and are crucial structural parameters that affect the performance of the ejector significantly. Multi-factors analysis is carried to gain the sensitivity of the crucial parameters and further optimize performance of the ejector on PEMFC. For low current (110 A), middle current (275 A), and high current (412.5 A), the order of influence of performance were (D > A > B > C > E), (D > A > B> E > C), and (D > C > E > B > A), respectively. The optimized ejector by multi-factor analysis method has a better performance than one optimized by single-factor. This study may provide a new way of thinking for optimization of structural parameters of any PEMFC ejector with various operating condition.