甲烷预冷膨胀循环空气涡轮火箭发动机性能分析

为研究以甲烷燃料为冷却剂的膨胀循环空气涡轮火箭发动机可行性及性能，采用部件法建立了甲烷预冷膨胀循环空气涡轮火箭（Air-Turborocket, ATR）发动机性能评估模型，研究了压气机压比和冷却剂当量比等参数在不同飞行状态下对发动机性能的影响，分析了不同来流工况下发动机正常工作对各部件的性能需求。计算结果表明，通过大于1.0倍当量比甲烷预冷作用，甲烷预冷膨胀循环ATR发动机能在压气机压比低于2.0条件下实现Ma0~4.0速域连续工作，但由于甲烷焓值较低，限制了压气机压比的提升，因此甲烷较低的单位功是限制发动机性能改进的主要因素；甲烷预冷膨胀循环ATR发动机的涡轮功率只有在较高落压比和甲烷压力条件下才能平衡压气机功率需求；冷却循环系统与空气的热力循环匹配问题是各部件协同工作的关键，通过适当选取发动机各部件控制参数，能在Ma0~4.0速域内获得1250~2114s的比冲、70~110s的单位推力和50%的总效率。

Performance Analysis of Expander Cycle Air-Turborocket with Methane-Precooled

In order to investigate the performance of expander cycle Air-Turborocket(ATR) engine with methane-pre-cooled, the engine performance evaluation model was established based on element-method, the effect of compressor pressure ratio and coolant equivalent ratio on engine performance under different flight conditions was studied, and the capibility requirements of each components for engine operation under different working conditions were analyzed as well. The calculation results show that the methane-pre-cooled expander cycle ATR with at least 1.0 equivalent ratio of methane coolant can realize the continuous work among Ma0~4.0 under the condition of lower than 2.0 compressor pressure ratio. The low unit power of methane is the main factor that limits engine performance, because the low enthalpy of methane restricts the improvement of compressor pressure ratio. The turbine power of the methane-pre-cooled expander cycle ATR can meet the compressor power requirement only under the condition of high turbine pressure ratio and coolant pressure. The matching problem between cooling cycle and air cycle is the key to synergistic work for the engine components. The specific impulse of 1250~2114s, specific thrust of 70~110s and total efficiency of 50% can be obtained in Ma0~4.0 by properly designing the control parameters of the engin components.