Ejector design and structural parameter optimization design of vehicle-mounted hydrogen supply circulation system

As the core component of the vehicle hydrogen supply cycle system, the performance of the hydrogen recovery efficiency of the ejector directly affects the hydrogen cycle utilization rate and the operation stability of the whole system. The ejector coefficient is a key indicator to measure the hydrogen recovery efficiency of the ejector, and its level determines the quality of the ejector effect. In order to improve the hydrogen recovery efficiency of the ejector, a high-efficiency hydrogen recovery ejector structure was designed. Based on the Sokolov structure design method, the preliminary structure size design of the ejector was carried out. The hydrogen recovery efficiency under start-up condition, steady-state condition and idle condition was studied. The uniform experimental design optimization method was used to optimize the structural parameters, and the multi-factor and interaction term stepwise regression analysis was carried out with the ejection coefficient as the highest weight. The results show that under the three working conditions, there is a peak point in the influence of radial structure size and convergence angle on the ejection coefficient, and the overall trend before and after the peak is first increased and then decreased. In the axial dimension, the influence of the length of the accommodating cavity, the length of the equal volume mixing cavity and the height of the in ejected hydrogen inlet on the ejection coefficient is very small and almost negligible. There is a peak point in the influence of the length of the inlet section of the high-pressure hydrogen, the length of the outlet section of the mixed hydrogen and the length of the nozzle distance on the ejection coefficient, and the overall trend before and after the peak increases first and then decreases. The optimized ejector achieves the improvement of hydrogen recovery efficiency under the three conditions of start-up, steady-state and idle speed. The hydrogen recovery efficiency is increased by 15.80 % under start-up condition, 29.58 % under steady-state condition and 19.31 % under idle speed condition.