截锥不同冷却结构对喷管腔体红外抑制特征影响的数值研究

Numerical investigation of effect of truncated cone with different cooling structures on infrared suppressing characteristics of nozzle cavities

对发动机喷管高温部件之一的截锥3-5μm波段上红外抑制特征进行了数值研究．在红外辐射信号较强的截锥前端布置气膜缝槽冷却结构和气膜孔冷却结构，将温度较低的外涵气流通过支板引入截锥，有效降低了截锥、支板的壁面温度和红外辐射强度．对两种冷却结构进行比较，结果表明，采用向下气膜缝槽冷却结构能够达到较好的红外抑制效果，但推力损失较大；采用气膜孔冷却结构，喷管红外抑制效果略有减弱，但推力损失较小．

The characteristics of infrared suppressing on 3--5μm band of truncated cone, which was one of the high temperature components of engine nozzle were numerically investigated. Different arrangements of film cooling gap and film cooling hole structures were disposed on the truncated cone which showing strong infrared characteristics, and cold gas flowed into truncated cone through blades from by-pass channel, causing wall tempera- ture drop of truncated cone and blades, furthermore, the infrared radiation intensity was de- pressed. By comparison of the two cooling structures, it is found that the method of film cooling gaps downwards can make wall temperature and infrared radiation intensity decrease more than that of film cooling holes, while lower thrust efficiency can be gotten.