考虑热力学效应的涡轮氧泵 环间隙泄 特性研究

To accurately analyze the leakage characteristics of the wear ring clearance and the influence of the leakage flow on the internal flow field of the liquid oxygen turbo pump, SST k-ω turbulence model and high resolution algorithm are used for numerical simulation of the pump based on full size and the whole flow field to investigate how thermodynamic effects affect under different flow rates, the external characteristics of the pump, the leakage flow rate of the wear ring clearance, and the cavitation characteristics. The results show that each empirical formula from Ovsyannikov can predict the leakage characteristics accurately near the rated operational conditions while it cannot be so accurate in the case of deviation from the rated conditions. The pump efficiency is higher and the leakage is larger for liquid oxygen compared with normal temperature water at the same volume flow rate, and the leakage difference is related to the flow rate of the pump. In the isothermal condition, the leakage flow rate is little affected by the temperature of the working fluid, and the leakage loss is larger when high temperature liquid oxygen is adopted as the working fluid under the rated operational condition. For thermodynamic effects, the temperature rise in the pump cavity and the wear ring clearance increases with the decrease of the flow rate of the pump and is about 1-3 K with the flow rate of the pump growing from 120% to 40%. Compared to the results in the isothermal condition, the pump head and efficiency slightly increase, and the vortex at the inlet and outlet of the wear ring clearance increases, but the leakage significantly decreases. The reduction in the leakage is inversely related to the flow rate of the pump, with a maximum reduction of 3%. Moreover, the cavitation in the wear ring clearance is aggravated.