Abstract: In order to acquire the infrared signature of serpentine nozzle， the study on the effects of the length ratio and the centerline on the infrared signature of serpentine nozzle had been performed. The results show that the gas infrared signature in the horizontal plane reduces by 61.1% on average when compared with that in the vertical plane. Otherwise， in the vertical plane， the wall infrared signature at negative azimuth angle is greater than that at positive azimuth angle. The relative differences of total infrared radiation intensity between the serpentine nozzles with different length ratio and centerline are between 2.2% and 6.3%. The length ratio and the centerline have significant influences on the flow performance， but their effect on the infrared signature is limited. And these two design parameters can be ignored in the design process of serpentine nozzle on the view of infrared suppression.

Key words: Serpentine nozzle；Infrared suppression；Infrared signature；Exhaust system

摘要： 为了深入理解和掌握S弯喷管的红外辐射特性，采用数值模拟的方法着重研究了轴向长度比和中心线变化规律这两个几何参数对S弯喷管红外辐射特性的影响。结果表明，S弯喷管在水平探测面上的燃气红外辐射强度比垂直探测面上的低61.1%。同时，在垂直探测面上，下方的壁面红外辐射强度高于上方的。轴向长度比和中心线不同的S弯喷管，总红外辐射强度的变化在2.2%～6.3%。虽然S弯喷管轴向长度比和中心线变化规律对喷管性能有显著的影响，但其对红外辐射特性的影响较小。因此，仅从红外辐射的角度，在S弯喷管的设计过程中轴向长度比和中心线变化规律可不作为主要考虑因素。

关键词: S弯喷管；红外抑制；红外辐射特性；排气系统