Numerical investigation of gas-liquid two-phase flow dynamics in a high-pressure liquid hydrogen pump

The reciprocating high-pressure liquid hydrogen (LH₂) pump is a core component of liquid hydrogen refueling stations. However, existing research lacks a systematic analysis of its working mechanism under gas-liquid mixing conditions. research on gas-liquid mixing conditions is of great significance reciprocating liquid hydrogen pumps. Based on a single-stage vacuum LH₂ pump, this study establishes a three-dimensional numerical model, incorporating an evaporation-condensation model to account for gas-liquid phase transitions. Results show that during the liquid inlet stage, the in-cylinder flow velocity first increases and then decreases, with the liquid volume fraction dropping to approximately 84% and the temperature remaining around 27.243 K. In the compression stage, lower initial pressure accelerates the process and reduces temperature rise. These findings provide a theoretical basis for optimizing the initial pressure and improving the performance of high-pressure LH₂ pump.