自燃推进剂内混式直流气液喷嘴的燃烧火焰特征分析OA

In order to investigate the gas-liquid flame characteristics of UDMH/NTO hypergolic propellant under sub/supercritical conditions,the internal mixing injector was chosen to stabilize the flame.The CH∗ chemiluminescence images of flame associated with different injectors and different conditions were obtained by high-speed ICCD camera.Flame gravity center(FGC)and proper orthogonal decomposition(POD)method were used to distinguish and describe the flame characteristics.The results show that there are three obvious stages during the ignition process.After the ignition pressure buildup is completed,the chamber pressure stabilizes,but the POD results suggest that there are several typical flame motions.Increasing the injecting angle between the liquid channel and gas channel of injector could promote the FGC to move upstream,however,the pronounced flame motions remain unchanged.In addition,comparing with the flame under the subcritical pressure,the flame associated with a supercritical pressure presents the feature of dense flow.