Design and performance investigation on adjustable ejector with petal spindle valve for high-power fuel cell adapted heavy-duty truck powertrain

The shape of the nozzle and operating conditions significantly influence the entrainment performance of ejectors. Utilizing the AVL Cruise-M platform, a simulation framework for hydrogen fuel cell heavy-duty vehicles and a 110 kW hydrogen fuel cell engine was established. Combined with CHTC-TT driving cycle simulations, data on hydrogen gas mass flow rate and pressure at the anode end of the fuel cell were obtained. Based on this data, a study was conducted to design and investigate an adjustable petal-shaped spindle valve ejector. The study examined the impact of ejector spindle valve structure and feed position on entrainment performance and stability. The results indicate that the designed petal-shaped spindle valve ejector effectively enhanced jet turbulence and material and energy exchange between primary and secondary flows and the entrainment ratio of petal spindle ejectors is 2.24 % higher than that of taper spindle ejectors in SP12 positioning. The entrainment ratio of the adjustable ejector ranges from 1.65 to 3.02 at output powers of 10 to 110 kW, meeting the hydrogen recirculation requirements for fuel cells across various power levels. Moreover, the ejector demonstrates rapid dynamic response capabilities, with relatively stable backpressure at the mixed flow outlet. Comparison with conventional commercial ejectors indicated superior overall performance and a larger operating range for the adjustable ejector.