波瓣喷管/气膜冷却混合管气动和红外辐射特性实验

Experimental on Aerodynamic and Infrared Radiation Characteristics of Lobed Nozzle/Film Cooling Mixing Duct

针对某型后向进气、前向排气的涡轴发动机用红外抑制器,提出了波瓣喷管和气膜冷却混合管组合的红外抑制概念,旨在进一步降低混合管壁面红外辐射强度。用实验的方法,对气膜混合管内流特性、红外辐射特性进行了研究。研究结果表明：混合管壁面的3个引射入口的静压都低于外界大气压力,从而自然形成引射驱动动力;引射流量比与主、次流温度比有关,通过实验得到的温度修正指数可以将冷态实验结果外推到热态情况;与一般混合管相比,整体引射流量提高30%,在3-5μm波段内,红外辐射强度降低了12%-27%,在8-14μm波段内,红外辐射强度降低了12%-28%,其总压损失仅仅提高了1%。

Aiming at the infrared suppressor for a type of turboshaft engine which exhausts in front, a new idea of suppressor structure combining lobed nozzle with film cooling mixing duct is brought forward, with the purpose of decreasing infrared radiation of the mixing duct wall. Through model experiment, the internal aerodynamic and infrared radiation characteristics of the filming cooling mixing duct are revealed. The experimental results show that the static pressure at the three pumping inlets is under the ambient pressure. And the drive force of pumping environment atmosphere is become naturally. The pumping ratio of mixing duct has a certain relation with the temperature ratios of the primary and secondary flows. The results on the hot condition can be deducted from that on the cold condition through the corrected index of temperature. Film cooling mixing duct enhances the pumping performance of the whole suppressor system by 30% comparing with the case without film cooling mixing duct, but induces the total pressure loss only by 1%. Infrared radiation intensity of the film cooling mixing duct is reduced by 12%-27% within 3-5 μm band and by 12%-28% within 8-14μm band.