一体化红外抑制器遮挡和出口修型对后机身表面温度和红外辐射特性的影响

Effects of sheltering and outlet shaping on surface temperature and infrared radiation characteristics of rear airframe with an integrating infrared suppressor

针对与后机身融合的一体化红外抑制器模型,采用数值模拟的方法研究了内部遮挡和出口修型对后机身表面温度场和红外辐射特性的影响。在混合管外部采用遮挡套或曲面遮挡板可有效降低后机身侧壁面对应混合管后段的局部区域最高温度,两种方式均可有效降低水平探测面以及铅垂面上方3~5μm波段和8~14μm波段红外辐射强度峰值;然而,加装遮挡套方式会影响旋翼下洗气流的导入,使3~5μm波段的红外辐射强度在铅垂面下方较基准模型有小幅的增加。对后机身排气口进行出口修型,虽然对降低后机身3~5μm和8~14μm波段红外辐射强度的作用效果并不显著,但可以有效消除排气出口下方壁面的高温区,其中采用狭窄流道引气冷却方式可以使得后机身侧壁仅高于环境温度10K左右。

A numerical investigation is performed to illustrate the effects of internal sheltering and outlet shaping on the surface temperature and infrared radiation characteristics of rear airframe with an integrating infrared suppressor.The results show that the internal sheltering between the mixing duct and rear airframe skin can decrease the peak temperature on the rear airframe side-surface corresponding to the mixing duct trailing section,either by a full-covering shelter or semi-covering contoured plate.Both schemes can effectively reduce the infrared radiation intensity in 3-5μm and 8-14μm bands detected in the horizontal detection plane as well as from the top in the vertical detection plane.However,the presence of a full-covering shelter affects the rotor downwash flow suction into the rear airframe,making the 3-5μm infrared radiation intensity a little higher than the baseline case,when viewed from the bottom in the vertical detection plane.The outlet shaping could effectively improve the temperature distribution on the rear airframe side-surface,although it shows a weak role on reducing the infrared radiation intensity in 3-5μm and 8-14μm bands.By using the slit outlet structure to cool the lower side-surface of the rear airframe,the peak temperature could be maintained close to the ambient temperature,within a 10Krelative increase.