水冲压发动机的热力性能分析

Thermodynamic calculation and analysis for water ramjet

针对水冲压发动机这一新型动力系统，详细分析了其工作过程，并建立了相应的热力计算模型。结合质量守恒方程、化学平衡方程和能量守恒方程建立了发动机热力计算理论，预估了发动机的性能，初步设定了燃烧室的工作压力，并分析了比冲、推力以及特征速度等性能参数随进水量的定性变化规律。综合考虑发动机性能及燃烧反应的启动温度，得出一次进水水燃比限定在0．5～1．9之间，总水燃比的上限为5．1，而水燃比为3．5时对应着最高比冲。

In order to obtain specific impulse as great as possible, and meanwhile to guarantee appropriate temperature and pressure, a dual water injection system was utilized in water ramjet. Through analysis on working process, corresponding thermodynamic cycle model was established. To investigate the performance of the engine, combining mass conservation equation, chemical equilibrium equation and energy conservation equation, detailed thermodynamic calculation was implemented. An appropriate chamber pressure is given preliminary. The qualitative relationship of performance parameter, such as specific impulse, thrust, exit temperature, etc, versus water-fuel ratio was obtained respectively. Then, the primal water-fuel ratio is determined between 0. 5 and 1.9. Guaranteeing the maximum total water-fuel ratio less than 5. 1 , the specific impulse could achieve optimal value while total water-fuel ratio is equal to 3.5.