进口压力对液氧涡轮泵一级液封轮密封性能的影响

Influence of Inlet Pressure on Sealing Performance of Primary Liquid-sealing Impeller for Liquid Oxygen Turbopump

液封轮作为一种非接触式密封能够很好地解决火箭发动机液氧涡轮泵密封端面磨损失效及泄漏量大的问题。该文以某火箭发动机液氧涡轮泵多级液封轮为研究对象,采用数值模拟方法研究了进口压力对液氧涡轮泵一级液封轮密封性能的影响,并以工作介质为液氮进行实验,验证了本文采用的一级液封轮数值计算方法的可靠性,以泄漏流量和增压系数为指标对计算结果进行分析。结果表明:一级液封轮后方密封腔体的压力和温度偏差分别为6.7%和8.2%,该数值计算方法可行;在10000 rpm的转速下,通过改变进口压力可以得到负压密封、等压密封和泄漏这三种典型密封状态;以增压系数和泄漏量作为密封状态的评判标准,给出了密封状态的分类以及增压系数对应密封状态的分析方法。总而言之,液封轮与转速及进口压力的合理匹配十分重要,在实际应用中想要实现更大压力的工作介质密封则需提高转速或更换密封能力更强的液封轮。

As a non-contact seal,the liquid-sealing impeller can well solve the problems of wear failure of sealing face and large leakage of liquid oxygen turbopump of rocket engine.In this paper,a multistage liquid-sealing impeller of liquid oxygen turbopump for a rocket engine is taken as the research object,and the influence of inlet pressure on the sealing performance of the primary liquid-sealing impeller of the liquid oxygen turbopump were numerically studied.The numerical calculation method of the primary liquid-sealing impeller is verified by experiment using the fluid medium as liquid nitrogen.Results show the numerical simulation method is feasible,and the deviation of pressure and temperature in the sealing chamber after the primary liquid-sealing impeller are 6.7%and 8.2%respectively compared with the experimental value of liquid nitrogen.When the rotation speed is 10000 rpm,by changing the inlet pressure,three typical sealing states such as negative pressure sealing state,isobaric sealing state and leakage state could be obtained.The pressurization coefficient and leakage flow rate are taken as the evaluation criteria of the sealing state,and the classification of the sealing state and the analysis method of the sealing state corresponding to the pressurization coefficient are given.Overall,it is very important to match the liquid-sealing impeller with the rotation speed and the inlet pressure reasonably.In practical application,in order to realize the working medium seal with greater pressure,it is necessary to increase the rotation speed or replace the liquid-sealing impeller with stronger sealing ability.