带全遮挡导流支板的二元排气系统与后体组合模型的流动传热与红外特性分析

Numerical study of fluid flow, heat transfer and infrared signature of 2D exhaust system model with full shielded guide vane combined with rear body

为了降低末级涡轮对排气系统尾向红外辐射贡献,通过设计导流支板实现对末级涡轮的全遮挡,运用数值模拟的方法研究了三种排气系统(基准轴对称排气系统、二元排气系统和带全遮挡导流支板的二元排气系统)与飞机后体组合模型的流动传热与红外特性,揭示了三种组合模型尾向3~5μm波段的红外辐射特性的一般规律。结果表明,二元排气系统与飞机后体组合模型和带全遮挡导流支板的二元排气系统与飞机后体组合模型在尾向的红外辐射强度,相对基准轴对称排气系统与飞机后体组合模型,均有所降低,在0°观测方向降幅分别为22.1%和46.9%。若全遮挡导流支板采用冷却技术,只要冷却效果达到0.282和0.482,组合模型的红外辐射强度在0°观测方向相比支板未冷却状态的降幅分别为20.4%和35.45%。

In order to reduce the contribution of the last-stage turbine of the infrared radiation in backward of the exhaust system, the full shielding guide vane(FSGV) is designed to achieve full shielding of the low-pressure turbine. Numerical simulation methods are used to study fluid flow heat transfer and infrared signature of three exhaust system(including baseline axisymmetric exhaust system,2D exhaust system and 2D exhaust system with FSGV) models combined with aircraft rear body, revealing the general rule of infrared radiation characteristics in the 3-5 μm band in backward of the three different combined models;the results show that compared with the baseline axisymmetric exhaust system model combined with aircraft rear body, whether it is a 2D exhaust system model combined with aircraft rear body or 2D exhaust system model with FASG model combined with aircraft rear body, the infrared radiation intensity has been reduced, and the drop rates are 22.1% and 46.9% respectively at a detection angle of 0°. If the cooling technology is adopted for the FSGV, as long as cooling efficiency reaches0.282 and 0.482, compared to uncooled state of the exhaust system, the infrared radiation in backward of the exhaust system can be reduced by 20.4% and 35.45%.