换热预冷发动机预冷特性和发动机性能数值研究

为深入了解换热预冷发动机换热器预冷效果和发动机性能，首先设计了叉排管束式细小通道换热预冷器，并采用非定常数值模拟方法对换热效果进行了仿真，然后结合换热预冷发动机性能计算程序对预冷发动机性能进行了研究。结果表明，飞行马赫数为2.5~4.0且氢气空气质量流比为0.03~0.09条件下，换热预冷器能将来流空气预冷90.6~471.2 K，低温氢气经吸热后温度升幅为266.1~455.3 K，换热效果良好。来流空气经预冷后涡轮发动机的飞行包线最高被拓展至马赫数4.0，达到了与超燃冲压发动机的衔接速域。相比于传统涡轮发动机，氢气空气质量流比为0.03时，本文换热预冷发动机加力状态推力能恢复至设计点推力水平；当氢气空气质量流比增加至0.09时，加力状态推力最高达到设计点推力的两倍左右。马赫数2.6以下换热预冷措施能小幅改善发动机比冲和耗油率（仅计算用于燃烧的氢气量）性能，而飞行速度大于马赫数2.6后换热预冷措施也难以抑制比冲和耗油率迅速恶化的趋势。

Numerical investigation of pre-cooling characteristics of heat exchange pre-cooling engine and engine performance

For a better understanding of the performance of heat exchange pre-cooling engine, a heat exchanger in which the tubes were mounted by staggered arrangement is designed firstly. Then, the pre-cooling characteristics of the heat exchanger are simulated numerically. Finally, the performance of the heat exchanger enhanced engine is analyzed theoretically. The simulation results confirm a favorable characteristics of the heat exchanger. On the condition that the mass flow ratio of hydrogen and air is 0.03-0.09 and the flight Mach number is 2.5-4.0, the total temperature of the incoming air can be cooled by 90.6-471.2 K through the heat exchange pre-cooler, the temperature of low-temperature hydrogen arises by 266.1-455.3 K. Analyses show that the heat exchange pre-cooling technology expands the flight envelope to Ma 4.0 for the conventional turbine engine, reaching the connecting speed range of scramjet. Compared with the conventional turbine engine, the thrust with afterburning can be recovered to as high as the thrust of designed point as the mass flow ratio of hydrogen and air is 0.03. While the mass flow ratio of hydrogen and air rises to 0.09, the thrust with afterburning can be improved to approximately two times the thrust of the designed point. Furthermore, the specific impulse and specific fuel consumption (only including the hydrogen for combustion) can be promoted slightly when the flight velocity is slower than Ma 2.6, whereas when the flight velocity exceeds Ma 2.6, pre-cooling will not effectively restrain the rapid deterioration of specific impulse and specific fuel consumption any more.