针对某型续航发动机在高海拔地区试验中出现的推力不足问题,分析其设计中存在的缺陷,发现问题在于:喷管出口静压与环境气压压差匹配特性随着海拔的增高发生剧变,从而造成燃气流场的改变。通过数字仿真及模拟试验验证该观点的正确性。提出通过调整续航发动机喷管的扩张比的方法,改善发动机喷口静压与高原大气压的压差,从而保证续航发动机的高原性能。经试验验证,该方案简单易行,具有工程应用性。

The article deeply analyzes the design of sustained motor to solve the problem of insufficient thrust which occurred in a test on high altitude localities. As the article points out, the press reduced as the altitude raised, which cause the changed of the matching between the nozzle outlet pressure and atmospheric pressure and the change of the gas flow field. Digital simulation and experiment proved the validity of the theory. Besides, the article also proposes improved methods. By adjusting the expansion ratio of engine nozzle, we improve the difference of the engine nozzle outlet pressure of and the atmospheric pressure, and ensure the performance of the cruising engine on the plateau. As prove in test, the improve scheme is simple and practical.