超燃冲压发动机喷管推力性能理论预测

超燃冲压发动机发展60多年来,虽然取得了很大的进步,但是对其推力大小的理论评估是一个没有很好解决的问题.超燃冲压发动机的推力主要由喷管产生,因此重点研究了喷管的推力特性.将燃烧室出口参数作为喷管入口边界条件,利用等熵膨胀理论,通过对喷管壁面压力积分,得到了简化的无量纲推力公式,获得了影响推力大小的关键参数和物理规律.理...

Theoretical Prediction on the Nozzle Thrust of Scramjets

A big progress has been made for scramjets in the past 60 years.However,whether it has enough thrust or not is not clear to date.In this paper,the thrust performance of the nozzle was analysed by using the isentropic expansion theory,because the thrust is mostly produced by the nozzle in scramjets.The parameters in the combustor were used as the boundary conditions.A dimensionless thrust equation was obtained by integrating the pressure along the nozzle wall.The key parameters and physical laws governing the thrust performance were discussed.The analysis results show that the supersonic combustion is good for producing higher thrust.The main way to get heavy thrust is to increase the combustion static pressure in the combustor.The analysis results are in good agreement with CFD results,which demonstrates its correctness.