Abstract Cavitation within injectors critically influences the performance and stability of liquid ammonia fuel systems. This study employs numerical methods to investigate the transient cavitation flow of liquid ammonia in multi-nozzle injectors. First, a three-dimensional computational fluid dynamics (CFD) model of the injector was established. The model couples the VOF multiphase flow model, the Realizable k-e turbulence model, and the Zwart-Gerber-Belamri cavitation model. Its accuracy was validated. This study employs numerical methods to investigate the transient cavitation flow of liquid ammonia in a multi-nozzle injector, focusing on the effects of inlet pressure (40-80 MPa) and outlet pressure (1-3 MPa) variations on cavitation evolution. Results indicate that inlet pressure is the dominant factor determining cavitation flow characteristics. Cavitation intensity, outlet velocity, and mass flow rate all increase with rising inlet pressure, directly impacting the atomization quality and combustion efficiency of ammonia fuel within the engine. Orifices 1-3 were highly sensitive to changes in inlet pressure. Orifices 4 and 5 achieve better flow output and stability through the expansion space of the pressure chamber. In contrast, the impact of outlet pressure is minimal, with overall parameter variations not exceeding 3.2%. The pressure chamber's buffering effect effectively mitigates the shock caused by fluctuations in outlet pressure. This work clarifies the role of pressure conditions on cavitation in ammonia injectors and provides direct guidance for designing high-performance, stable injection systems.
Li et al. (Thu,) studied this question.