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为了阐明进气预冷膨胀式空气涡轮火箭发动机在最大状态下的部件匹配规律和性能特点,基于ε—NTU法建立了换热有效度随工况改变的预冷器模型,完成了氢燃料发动机的性能仿真与分析。增大涡轮前压力、燃料流量,同时减小尾喷管喉道和出口面积,可实现压气机工作点沿等物理转速线由堵塞区向喘振边界移动,压气机压比及燃空比均增大。在此过程中,发动机若在低马赫数工作,尾喷管内燃气总压、总温升高使推力增大;在近堵塞区域,压比迅速增大导致比冲上升;在近喘振区域,压比增大减缓,燃空比的上升导致比冲下降。若在高马赫数工作,高温米流使压气机工作于低折合转速区域,工作点在等物理转速线上由堵塞区向喘振边界移动时,燃空比增加补偿了空气流量下降导致的推力衰减,总推力基本保持不变;由于低折合转速下压比增大减缓,增大的燃空比使比冲下降。
In order to clarify the matching rules and performance characteristics of the air precooling expansion air turbine rocket engine under maximum conditions, a precooler model was established based on the ε-NTU method to change the heat transfer effectiveness with operating conditions. The hydrogen fuel engine Performance simulation and analysis. Increasing the turbine forward pressure and fuel flow and reducing the throat and outlet area of the tail pipe nozzle can move the compressor working point along the physical speed line from the blockage area to the surge boundary and the compressor pressure ratio and the fuel-air ratio Increase. In the process, if the engine works at a low Mach number, the total pressure of the gas in the tail pipe will increase, and the total temperature will increase so that the thrust force will increase. In the area near the blockage, the pressure ratio increases rapidly and the specific impulse rises; Pressure ratio increases slowed down, the rise of the air-fuel ratio led to the specific impulse down. When working at a high Mach number, the high-temperature meter flow causes the compressor to operate in a low-fold speed range and the operating point shifts from the blocked zone to the surge margin at a physical speed line, and the increase in the air-fuel ratio compensates for the thrust due to the reduced air flow Attenuation, the total thrust remained unchanged; due to low speed under the pressure ratio increases slowed down, increasing the air-fuel ratio so that the specific red.