发动机三喷管流场和红外辐射特征数值研究

Numerical Simulation on Engine Three-Nozzle Flow Field and Infrared Radiation

对火箭发动机三喷管喷流场和红外辐射特性进行了数值模拟,得到了三股燃气射流在射流起始段互相作用而产生的复杂流场特征。当射流喷出后,由于压力高于背压,气流发生膨胀,射流边界向内收缩,同时会产生压缩波以抑制因压力降低而产生过膨胀现象的出现;压缩波扩展并增强为激波,随下游距离增加,膨胀波及压缩波区的尺寸和波强不断削弱。一旦射流发展至下游26倍助推级发动机排气喷管直径处,三股射流将合并成为一股射流而继续发展。三喷管排气喷流的红外辐射强度空间分布与单喷管喷流的红外辐射空间分布基本一致,但三喷管的排气喷流和内腔的总体红外辐射在水平面和铅垂面上的空间分布存在显著的差异。

The flow field and infrared radiation characteristics of three-nozzle for the rocket motor are nu- merically investigated. The interaction of three jets ejected from three-nozzle is analyzed and the flow field is obtained. When the jets are ejected from nozzle exits under the condition that the jet pressure is higher than the back pressure, the inflation of jets happens and the jet boundary contracts inward, thus producing the compression wave to suppress the over-expansion due to the reduction of pressure. Then compression wave expands and enhances for shock. And the expansion and compression wave zone size decreases, as well as intensity weakens along streamwise direction. Once the distance from the nozzle exit reaches 26 times of nozzle diameter, the three jets are merged together to form a jet. The plume in- frared radiation distribution of the three-nozzle is similar to that of the single nozzle. It is evident that the total infrared radiation distribution in horizontal plane is different significantly from that in the vertical plane for the three-nozzle.