空气涡轮火箭发动机热力循环特性分析

Analysis on thermodynamic cycle characteristics of air-turbo-rocket engine

采用热力学第一定律分析法分析了液体推进剂空气涡轮火箭发动机(Air Turbo Rocket,ATR)的基本热力过程,通过能量平衡计算得出了理想循环功、热效率和发动机比冲,确定了影响理想热力循环性能的5个特征参数,进而分析了地面静态和飞行状态下热力学特征参数对发动机热力循环性能的影响规律。结果表明:提高燃烧室温比、发生器温比和涡轮落压比有利于ATR循环功和燃料比冲性能的提升,提高压气机压比将在增大循环功和热效率的同时降低燃料比冲性能;理想循环热效率随来流马赫数的增大而增大,循环功和燃料比冲随来流马赫数的增大而先增大后减小,存在极大值。

The basic thermodynamic process of liquid propellant air-turbo-rocket(ATR) engine is analyzed with the first law analysis method of thermodynamics. The cycle work, thermal efficiency and specific impulse of the ideal ATR engine thermodynamic cycle were deducted through calculation of the energy balance. Furthermore, five thermodynamic characteristic parameters which might affect the ideal thermodynamic cycle performance were determined. The effects of these thermodynamic characteristic parameters on the performance of the engine thermodynamic cycle in the ground static state and flight state were analyzed. The results indicate that the increase of turbine expansion ratio, temperature ratios of gas generator and combustion chamber is helpful to the improvement of ATR thermodynamic cycle work and specific impulse, but the fuel specific impulse performance will be decreased while cycle work and thermal efficiency are increased if the compressor pressure ratio is increased; the ideal thermal efficiency increases with the increase ofincoming flow Mach number, whereas the thermodynamic cycle work and fuel specific impulse increase first, and then decrease with the increases of incoming flow Mach number.