Numerical simulation of cryogenic cavitating flow in liquid hydrogen turbopump

Cryogenic cavitation constitutes a critical factor affecting the performance of liquid hydrogen turbopumps. To mitigate cavitation effects, this study couples the VOF model with a full gas model to numerically analyze the flow characteristics and cavitation behavior of liquid hydrogen turbopumps under cryogenic conditions. The evolution of bubble morphology and size distribution was investigated under varying outlet pressure conditions. Considering the thermal sensitivity of liquid hydrogen's saturation vapor pressure, the cavitation behavior in turbopumps was systematically analyzed across varying temperature regimes. The numerical results were validated against Hord's classical hydrofoil experiments, demonstrating model accuracy. The results demonstrate that elevated outlet pressure significantly suppresses trailing-edge cavitation while intensifying vortex phenomena. The cavitation behavior is jointly governed by the variation of liquid hydrogen's saturation vapor pressure and thermodynamic effects, exhibiting a critical transition at around 20.7K: Below this temperature, the vapor volume fraction shows positive correlation with temperature due to the accelerated cavitation promoted by the steep rise in saturation vapor pressure; above 20.7K, however, increased latent heat absorption during vaporization induces localized temperature depression in the cavitation zone, leading to thermodynamically dominated suppression of cavitation in LH 2 turbopumps. The findings elucidate the intrinsic cavitation characteristics within liquid hydrogen turbopumps, revealing a temperature-dependent cavitation behavior unique to cryogenic hydrogen environments, which provides critical guidance for the optimized design of LH 2 turbopump systems.