Choice of Gas Temperature at Turbopump Turbine Inlet

The article considered some issues of gas temperature choosing at liquid rocket engine turbopump turbine inlet. Turbine is one of the key elements of the engine and its operability depends on the gas temperature. In addition, turbine inlet gas temperature evaluates its power and main parameters of the engine - chamber pressure and thrust. The higher gas temperature at the turbine inlet gives higher chamber pressure and better engine performances. The acceptable turbine structure temperature determined by required safety margins and durability of the turbine rotor blades. For expendable engines, safety margin is determined by the material short-term strength at maximum gas temperature. For reusable engines with a long service life, the safety factor is determined by material long-term strength. The article presents main factors affecting to the choise of generator gas temperature. It shows that one of the main factors is the temperature field nonuniformity at the turbine inlet. The maximum acceptable temperature choice is determined not so much by the engine schematic - oxidizer or fuel closed cycle, but by the strength and durability of the structure with temperature factors influence.