液体火箭发动机诱导轮空化热力学效应研究

Study of Cavitation Thermodynamic Effect of Liquid Rocket Engine Inducer

关键词:  液体火箭发动机  诱导轮  空化  热力学效应  可视化

Key words:  Liquid rocket engine  Inducer  Cavitation  Thermodynamic effect  Visualization

摘要:

为了研究空化热力学效应，以模型诱导轮为研究对象，改变流量、水温等条件，对其内部空化流动进行了可视化实验研究，完整记录了从空化初生至性能断裂点各工况的空化区形态。结果表明：温度对诱导轮无空化水力性能没有显著影响，但是高温下诱导轮的空化性能断裂点被显著延后，体现了热力学效应的影响。对比不同温度下的空化区形态，发现热力学效应的强弱与流动工况密切相关，在小空化数下体现得更为显著。同时引入一种半经验的理论模型预测热效应对空化性能的影响，小流量（Φ=0.071）下预测结果与实验结果平均偏差为5.5%，大流量（Φ=0.088）下平均偏差为10.8%，验证了模型在本文应用条件下的可靠性。

Abstract:

To study the cavitation thermodynamic effect, a series of visualization experiments of the cavitating flow inside a model inducer were carried out under different flow coefficients and temperatures, the cavitation structures were documented integrally from the inception point to the breakdown point. It is found that temperature shows little influence on the non-cavitation hydraulic performance, but the breakdown point is remarkably delayed at high temperatures, indicating the influence of the thermodynamic effect. The comparison of cavitation structures at different temperatures implies that the strength of thermodynamic effect is closely related to the flow condition and it is more conspicuous at smaller cavitation numbers. At last, a semi-empirical theoretical model was introduced to predict the influence of thermodynamic effect on the cavitation performance. The averaged deviation between predicted and experimental results is 5.5% at small flow condition (Φ=0.071). The averaged deviation is 10.8% for the larger flow condition (Φ=0.088). Thus the validity of the predicted model is verified in the investigated conditions in this study.