上面级发动机推力室喷管延伸段气膜冷却研究

Research on gas film cooling at nozzle extension section of thrust chamber for upper stage engine

上面级发动机采用四氧化二氮/偏二甲肼为推进剂,将涡轮排气引入推力室喷管气膜冷却喷管延伸段。仿真计算和热试车表明:推力室主燃气与涡轮排气压力在同一截面处相等,涡轮排气沿喷管延伸段壁面流动形成紧贴喷管壁面的气膜,对主燃气无扰动,对喷管延伸段起到冷却保护作用。推力室喷管延伸段传热计算值和热试车延伸段温度测量值吻合,排气集合器内压力基本均匀,满足工程应用需要。

Nitrogen tetroxide （N204）/unsymmetrical dimethylhydrazine （UDMH） is adopted as propellant of the upper stage engine. The turbine exhaust gas is imported into the nozzle extension section of thrust chamber to form low temperature gas film. The simulation calculation and the ground hot-firing test were performed to validate the cooling method. The results show that the pres- sure of the main gas from the thrust chamber is equal with that of the turbine exhaust gas, and the gas film formed by the turbine exhaust gas which flows along the nozzle extension section and appresses with the inner wall of the nozzle has no perturbation to the main gas, and protects the nozzle exten- sion section from high temperature. The value of heat-transfer calculation of the nozzle extension sec- tion of thrust chamber coincides with that of temperature detection during the ground hot-firing test. The pressure in the exhaust gas collector is basically uniform. It satisfied the requirements of a pro- ject.