涡扇发动机排气系统中心锥气膜冷却结构的气动和红外辐射特性实验

以降低涡扇发动机排气系统红外辐射为目的,针对某型涡扇排气系统构建1/3缩比模型,采用实验的方法比较了中心锥有/无冷却的排气系统喷流温度场和红外辐射场,验证了中心锥冷却结构能够大幅度降低涡扇发动机排气系统尾向红外辐射强度.研究结果表明：中心锥表面在外涵气体冷却下温度降低,同时尾焰核心温度也降低.当涵道比为0.3时,在0°～10°范围内,气膜冷却中心锥体排气系统红外辐射降低24%～32%;在20°～90°范围内,红外辐射强度降低0.8%～2.1%.当涵道比增加到0.8时,0°方向的红外辐射强度降低60%;20°～90°范围内的红外辐射强度降低了33%～51%.

Experiments on aerodynamic and infrared radiation characteristics of film-cooling center-body exhaust system for a turbofan engine

For depressing the infrared radiation of the turbofan exhaust system,a 1/3 scaled model was constructed according one-type engine to investigate the plume temperature and infrared radiation for exhaust system with/without cooling center body,to validate the suppression capability of cooling center body.The experimental datum shows the temperature of the center body surface decrease under the bypass flow cooling.On the condition of bypass ratio 0.3,the infrared radiation intensity of the exhaust system with cooling center body depress by 24%~32% at the detected angle from 0° to 10° comparing to that of the baseline center body.When the bypass ratio increase to 0.8,the infrared radiation intensity of the exhaust system with cooling center body depress by 60% at the detected angle of 0°,and by 33%~51% at the detected angle of 20° to 90°.