涡扇发动机轴对称分开和混合排气系统红外辐射特征的对比

Comparative investigation of infrared radiation characteristics of axisymmetrical individual and mixing exhaust systems in turbofan engine

用数值模拟的方法对比研究了涡扇发动机轴对称分开和混合排气系统的红外辐射特征.排气系统的流场采用商业软件进行模拟,红外辐射特征采用根据反向蒙特卡洛法自主开发的软件进行计算,计算分析了两种排气系统在3～5μm波段红外辐射的空间分布以及喷管内不同固体部件在探测方向上的辐射贡献.在红外辐射特征计算过程中,考虑了喷管内壁的发射和反射以及燃气组分二氧化碳、水和一氧化碳的吸收-发射等影响.结果表明:两种排气系统红外辐射的空间分布特性不同;混合排气喷管的积分辐射强度在方位角为0°～10°时大于分开排气喷管,在其他方位角范围内均小于分开排气喷管.

The infrared radiation（IR） characteristics of axisymmetrical individual and mixing exhaust systems in turbofan engine were investigated with the method of numerical simulation.The flow fields of exhaust systems were simulated with commercial software.The IR characteristics were calculated with an IR analysis software based on reverse Monte-carlo method developed by our research group.The IR characteristics in the waveband of 3-5 μm of the two exhaust systems and the IR contributions of different solid parts in the nozzles in different detection directions were calculated and analyzed.In the process of IR computation,the emission and reflection of the wall in the nozzle and the absorption and emission of CO2,H2O and CO in the gas jet were considered.The results show that the spatial distribution characteristics of IR of the two exhaust systems are different.The integral IR intensity of the mixing exhaust nozzle is less than that of the individual one except in the azimuth angles of 0° to 10°.