Abstract:

For the high integration and lightweight requirements of a 130 kW automotive fuel cell system， a compact hydrogen injector is designed. Computational fluid dynamics （CFD） methods are used to examine the effect of the key structural parameters （mixing chamber length， diffuser length， nozzle exit position， mixing chamber diameter， and diffuser angle） on its performance. The fully optimized compact hydrogen ejector's total length is only 53.8% that of the original size hydrogen ejector. The steady-state characteristic test results show that the 130 kW fuel cell system equipped with the compact hydrogen ejector achieves the design requirements， with a stack efficiency of 51.3% and a system efficiency of 44.3%. The compact hydrogen ejector shows superior hydrogen recirculation performance under conditions when the stack power is less than 60 kW. Moreover， it can meet the requirements of fuel cell systems that demand a recirculation ratio greater than 0.5 under all operating conditions.

Key words: fuel cell systems, hydrogen ejectors, compact design, CFD simulation, hydrogen recirculation ratio