通过数值计算和模拟实验研究了椭圆形排气系统的流动、传热和红外辐射特征分布，并与基准轴对称排气系统进行了比较。探测角在 5.～20.内，椭圆形排气系统的红外积分辐射强度随着角度增大迅速降低，在 20.～90.内，红外积分辐射强度降低速度变缓。与轴对称排气系统相比，在 3～ 5 .m波段，椭圆形排气系统红外积分辐射强度在 0.方向降低了 8.36%；在 45°方向降幅最大，窄边探测面与宽边探测面分别降低了 55.29%和 56.76%；在 90.方向，窄边探测面与宽边探测面分别降低了 36.00%和 5.80%。在 8～14 .m波段，椭圆形排气系统红外积分辐射强度在 0°方向降低了 14.76%；在 45°方向降低幅度最大，窄边与宽边分别降低了 36.98%和 41.76%；在 90°方向，窄边探测面与宽边探测面分别降低了 18.18%和 15.15%。结果表明，采用椭圆形排气系统，相比轴对称排气系统，强化了内涵高温燃气与外涵气体以及喷流与环境冷气的掺混，使得喷流温度衰减增强，高温核心区长度降到轴对称排气系统的 43.1%，起到明显的红外抑制作用。

The characteristics of the flow, heat transfer, and infrared radiation distribution of the elliptical exhaust system were numerically and experimentally studied. The results were compared with those of a benchmark axisymmetric exhaust system. The infrared signature of the elliptical exhaust system decreased rapidly with an increase in the detection angle in the range of 5°-20°, and it decreased slowly in the range of 20°-90°. In 3-5 .m wavelength bands(compared with the axisymmetric one), the infrared signature of the elliptical exhaust system decreased by 8.36% at the 0° detection angle; the maximum decrease rate was reached at the 45° detection angle, and the infrared signature in the horizontal and vertical planes of the detection angle decreased by 55.29% and 56.76%, respectively. At a 90° detection angle, the infrared signature in the horizontal and vertical planes decreased by 36.00% and 5.80%, respectively. In 8-14 .m wavelength bands(compared with the axisymmetric one), the infrared signature of the elliptical exhaust system decreased by 14.76% at the 0° detection angle; the maximum decrease rate was reached at the 45° detection angle, and the infrared signature in the horizontal and vertical planes of the detection angle decreased by 36.98% and 41.76%, respectively. At the 90° detection angle, the infrared signature in the horizontal and vertical planes decreased by 18.18% and 15.15%, respectively. The results show that the elliptical exhaust system intensifies the mixing of hot gas in the core and air flow in the bypass, as well as the jet and environment air, compared with the axisymmetric one. The length of the jet core region of the elliptical is shortened to 43.1% of the axisymmetric one, which suppresses the infrared signature.