涡轮与冲压组合动力高温进气预冷特性

针对涡轮基冲压组合循环发动机中高温进气影响涡轮发动机性能的问题,开展实际某高空模拟试验进气预冷段的数值分析。基于欧拉-拉格朗日多相流方法解析气液两相热质传输过程,探索射流冷却对不同高空高马赫数进气条件时预冷段内温度和压力的沿程变化规律。结果表明,射流冷却对流场具有明显地温降效果。带有射流装置的预冷段内流动损失是以由黏性耗散所引起的耗散熵产为主,而由气-液传热温差所引起流场温度梯度变化的加热熵产并不显著。对比高空模拟试验进气工况在射流量4%~7%的冷却效果发现,预冷段内气流温降程度为32.30~90.08 K,冷却前后总压降系数范围由1.42%~1.86%降低到0.95%~1.46%。因此,射流冷却技术在一定程度上改善涡轮发动机在高空高马赫数工作时进气流场特性。 

Pre-cooling characteristics of high temperature inlet air for turbine power combined with ramjet

To solve the negative effect of high temperature inlet air on the turbo engine performance in the turbine-based ramjet combined cycle engine, numerical analysis on the pre-cooling section of a real high-altitude simulation experiment was carried out. Based on the Eulerian-Lagrangian multiphase flow method, the heat and mass transfer process of gas-liquid two-phase was analyzed. And then, the temperature and pressure fields in the pre-cooling section were explored at different high altitudes and high Mach number inlet air conditions. Results showed that mass injection had an obvious improvement on temperature drop. The flow loss in the pre-cooling section with injection device was mainly caused by the dissipative entropy production due to the viscous dissipation, while the heating entropy production caused by the temperature gradient change of the flow field due to the gas-liquid heat transfer temperature difference was not significant. By comparing the cooling effect of 4%-7% water/air ratio at the high-altitude simulation inlet air conditions, it can be discovered that the airflow temperature drop in the pre-cooling section was within the range of 32.30-90.08 K, and the total pressure drop coefficient was reduced from 1.42%-1.86% to 0.95%-1.46% before and after mass injection cooling. Therefore, mass injection cooling can improve inlet air flow field characteristics of turbine engine at high altitude and high Mach number.