超燃冲压发动机性能预测工程方法

Engineering method of scramjet engine performance prediction based on nozzle exit pressure

基于一维流体动力学守恒关系模型和燃烧化学平衡流动假设,建立了超燃冲压发动机内推力、比冲与尾喷管出口压力的关联式,消除了以往实验中存在的超燃冲压发动机性能评估的困难。利用该关系式对超燃冲压发动机燃烧室实验模型推力增益进行了计算,通过与实验测量值的对比,校核了燃烧效率。对配合现有燃烧室模型、进气道和尾喷管的一体化发动机推力性能进行了评估,获得了发动机内推力系数、比冲与尾喷管出口压力关系曲线,为超燃冲压发动机性能快速评估和优化设计提供依据。

Relations of the internal thrust and specific impulse with the nozzle exit pressure have been established by means of one-dimensional fluid dynamics conservation models and chemical equilibrium hypothesis. With these new relations, difficulties in estimating the performance of scramjet engines based on experimental measurements can be removed. Thrust augmentations of experimental scramjet combustors have been obtained from the present relations and compared with the measurements on thrust increment to calibrate the combustion efficiencies. The thrust performance of the scramjet engine is estimated, and the curves of internal thrust coefficient, specific impulse and nozzle exit pressure are obtained based on the nozzle exit cross section, which can provide engineering basis for the integral performance assessment and optimal design of the scramjet engine and is valuable for experimental study.