双模态超燃冲压发动机准一维流耦合方法与验证 *

Analysis and Verification of Quasi One Dimensional Flow for Dual Mode Scramjet

关键词:  双模态  冲压发动机  准一维流  耦合  试验验证

Key words:  Dual mode  Ramjet  Quasi one dimensional flow  Coupling  Verification

摘要:

为改善双模态超燃冲压发动机的耦合分析精度和计算周期过长问题，提出了一种基于准一维流的内流耦合分析方法，该方法适用于隔离段和双模态燃烧室的耦合求解，解决了亚燃模态下由于热壅塞而产生的背压问题，完成隔离段和燃烧室的流场匹配分析，得到双模态流场和火箭基组合循环发动机在亚燃和超燃模态下的沿程流动特性。研究结果表明:(1)相对于双模态超燃冲压发动机直连试验结果，亚燃模态下隔离段的分离点预测误差在1.4%～11.2%，流道峰值压强预测误差在15.6%～21.6%，流道沿程压强预测的平均误差在9.6%以内，在超燃模态下，峰值压强预测误差小于3.75%，峰值压强的位置预测误差小于2%。(2)相对于RBCC发动机一体化自由射流试验结果，分离点预测误差小于2.1%，流道沿程压强平均误差小于10.5%。对于双模态超燃冲压发动机，本文方法具有一定的可信度。

Abstract:

In order to improve analyzed precision and long period of calculation problem for dual mode scramjet， a coupling method for internal flow analysis is presented based on the quasi one dimensional flow. Such method can be used in the coupling analysis of isolator and combustor of dual mode scramjet. It solves the back pressure matching problems of the isolator and the combustor which is caused by thermal choking in ramjet mode. The flow matching analysis of isolator and combustor is completed， and the flow performance along the channel of dual mode scramjet and rocket based combined cycle (RBCC) engine in ramjet and scramjet mode is obtained. The results show that， (1) Comparing to direct connection test of dual mode scramjet mode， the predicted error of separated point of the flow in isolator is between 1.4% and 11.2%， and the predicted error of the maximum pressure is between 15.6% and 21.6%， but the average error of the pressure along the channel is less than 9.6% in ramjet mode. In scramjet mode， the predicted error of the maximum pressure is less than 3.75%， and the error of the location of the maximum pressure is less than 2%. (2) Comparing to integral free jet test of RBCC engine， the predicted error of flow’s separated point in isolator is less than 2.1%， the average error of the pressure along the engine’s channel is less than 10.5%. The comparison shows that the quasi 1-D method in this paper has certain credibility for dual mode scramjet.