低温诱导轮空化特性数值计算研究

为研究低温诱导轮的空化性能，对液氮诱导轮空化流动进行了数值计算研究.数值计算采用了考虑旋转修正的FBM湍流模型和考虑热力学修正的Singhal空化模型.数值结果与实验进行对比，验证了数值计算方法的准确性.结果表明，随着空化数的降低，诱导轮空化分为无空化、间隙空化以及回流涡空化三个典型阶段.在研究选取的温度区间内（77.5 K≤T≤83 K），诱导轮不同空化阶段的分界点几乎不随温度变化.随着液氮温度的升高，诱导轮内部空穴体积呈现先增后减的趋势.对诱导轮空化热力学效应进行分析表明，当液氮温度较低时，热力学效应不显著，韦伯数主导着空化的发展；当液氮温度较高时，热力学效应增强，从而抑制了诱导轮内部空化的发展. 

Numerical Study on the Inducer Cavitation in Cryogenic Fluids

In order to investigate the cavitation performance of inducer with cryogenic fluids, the cavitating flows inside an inducer with liquid nitrogen was simulated. In the numerical method, a FBM turbulence model with the rotational correction and Singhal cavitation model with the thermal correction were applied. The numerical method was verified by the general agreement between the numerical results and experimental data. The results show that, with the decreasing cavity number, three typical cavitation pattern in inducer can be observed, namely no-cavitation, gap cavitation, and back-flow vortex cavitation. The critical point for different cavitation stages will not change with the temperature changing(77.5 K≤T≤83 K). The cavity volume inside inducer increased at first and then decreased with the increasing temperature of liquid nitrogen. This is because the Weber number dominates the development of cavitation at low temperature while thermal effects aren't remarkable. As temperature increases, thermal effects dominates the cavitation dynamics, which suppresses the development of cavitation, while the thermal effects becomes more and more significant when the temperature is higher and the cavitation is highly suppressed.