非对称超声速喷管内流动分离非定常特性  

Unsteadiness of flow separation in an asymmetric supersonic nozzle

作　　者：何成军 李建强[2] 黄江涛[1] 李耀华[2,3] 陈宪[1] HE Chengjun;LI Jianqiang;HUANG Jiangtao;LI Yaohua;CHEN Xian(China Aerodynamics Research and Development Center,Mianyang 621000,China;High Speed Aerodynamics Institute,China Aerodynamics Research and Development Center,Mianyang 621000,China;College of Aerospace Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]中国空气动力研究与发展中心,绵阳621000 [2]中国空气动力研究与发展中心高速空气动力研究所,绵阳621000 [3]南京航空航天大学航空学院,南京210016

出　　处：《航空学报》2022年第1期294-304,共11页Acta Aeronautica et Astronautica Sinica

摘　　要：综合采用流场观测和动态压力测量技术,对非对称超声速喷管分离流状态下喷管内激波结构和壁面动态压力进行了试验测量,通过壁面压力时频特性分析获得非对称喷管内不同流动分离模态的流动非定常特性。结果表明:在喷管落压比(NPR)为1.8~12.7范围内,喷管内流场结构由下偏向上偏转换;上壁面流动分离模态经历了受限激波分离(RSS)、末端振动状态和自由激波分离(FSS);下壁面流动分离模态主要为FSS;流动分离模态为RSS时,Schmucker分离预测标准不再适用。RSS和末端振动状态模态下,尽管分离间歇区壁面动态压力具有相似的低频特征,激波运动呈显著低频特征,但末端振动状态模态下频率值略高,主要是由于流动再附点近喷管唇口,分离剪切层撞击喷管出口位置,剪切层的不稳定性影响了分离激波的振荡特性。Using flow visualization and dynamic pressure measurement technology,the shock structure and dynamic pressure on the wall in an asymmetric supersonic nozzle with flow separation were experimentally measured.The time and frequency domain features of the wall pressure were analyzed to obtain the characteristics of the unsteady flow in different modes of flow separation inside the nozzle.The results show that when the Nozzle Pressure Ratio(NPR)increased from 1.8 to 12.70,the flow field structure inside the nozzle shifted from the downward to upward pattern.On the upper wall of the nozzle,there were three different modes of flow separation:Restricted Shock Separation(RSS),end effect,and Free Shock Separation(FSS).On the lower wall,the main mode of flow separation was FSS.In the RSS mode,the separation data began to deviate from the Schmucker’s criterion.In both the RSS and end effect modes,the wall in the intermittence region was under low-frequency pressure and the shock motion exhibited obvious low-frequency characteristics.In the end effect mode,the frequency value was slightly higher as the reattachment point comes in very close proximity to the nozzle lip,the separated shear layer impinges on the nozzle exit,and instability of the separated shear layer has obvious influence on motion of the separation shock.

关 键 词：非对称喷管 受限激波分离 末端振动状态 非定常 分离剪切层 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]