通过模型实验和数值计算相结合的方法研究了带波瓣混合器的涡扇发动机排气系统的红外辐射特性, 并与相应的环形混合器排气系统对比。研究结果表明: 波瓣混合器可以有效的增强内、外涵气流的掺混作用, 降低尾喷流的温度,从而降低喷流红外辐射; 相比环形混合器排气系统, 波瓣混合器排气系统红外辐射强度在喷管正后方0°方位降低9%以上, 在侧向90°方位降低39%以上; 轴对称喷管壁面的低发射率高反射率对排气系统内部高温部件辐射的反射作用强烈, 对排气系统在40°~70°方位角的红外抑制效果不利, 因此, 对于涡扇发动机自身温度较低的喷管壁面, 建议使用高发射低反射特性的材料或涂层, 以增加排气系统的红外抑制效果。

The infrared (IR) characteristic of a turbofan engine exhaust system with lobed mixer was studied experimentally and numerically, and the results were compared with a relevant annular mixer exhaust system. The results show that, the lobed mixer can enhance the mixture of core flow and fan flow and reduce the plume temperature, making the plume IR radiation attenuated; compared with the annular mixer exhaust system, the IR radiation intensity of the lobed mixer exhaust system reduces at least 9% in the direction right behind the nozzle exit, and reduces more than 39% in the direction vertical to the axis of the nozzle exit; the axisymmetric nozzle with low emissivity and high reflectivity has negative effect on IR suppression because of its strong reflection to the radiation of the high temperature components within angles range from 40° to 70°, thus, it is appropriate to increase emissivity and reduce the reflectivity of nozzle wall in order to achieve better IR suppression.