A generalized thermodynamic phase transition model based on bubble growth analysis for cavitating flow considering thermal effects

Thermal effects play a crucial role in cavitating flows involving thermo-sensitive fluids, particularly in high-pressure fuel injection systems, hydrofoils, and aerospace propulsion, where phase transition thresholds are approached. Unlike isothermal cavitation in water at room temperature, the significant variations in vapor pressure and liquid-vapor density under thermal conditions introduce complex dynamics that profoundly influence bubble growth, phase transition mechanisms, and overall system performance. While cavitation models based on bubble growth theory are commonly employed to model inertia-driven cavitation phase change processes, the modeling of thermal-diffusion-driven or coupled-phase transition processes in thermo-sensitive fluids remains a challenge. This study presents a comparative analysis of multistage bubble growth dynamics under varying thermodynamic conditions. A novel quantitative approach is introduced, incorporating key parameters such as the relative error rate between different phase change models and the critical time, thereby facilitating the differentiation of bubble growth stages and enabling a detailed assessment of thermal effects. The results show that the second critical time is approximately 250 times the first critical time. Based on an analysis of the bubble growth process, the Mikic–Rohsenow–Griffith–Theofanous–Patel (MRG-TP) bubble growth model, which accounts for both inertial forces and thermal diffusion and is applicable across all stages of bubble growth, is integrated into the cavitation phase change model. Consequently, a new generalized thermodynamic phase transition model (TPTM) is developed for simulating thermo-sensitive fluid cavitating flows. The accuracy of this model is validated through comparisons with experimental data on cryogenic liquid nitrogen cavitation flow around hydrofoils.