用Tam-Ganesan湍流模型研究排气系统红外辐射特性

通过三维流场、介质的质量浓度场与辐射场耦合求解方法,计算了1台有中心锥的轴对称喷管的空腔-喷流组合红外辐射特性.利用专门为自由剪切流动发展的Tam-Ganesan湍流模型,有效提高排气系统红外辐射模拟精度.采用有限体积法（FVM）结合窄带模型（NBM）计算了排气系统在3～5μm波段的辐射传输问题,并考虑大气衰减作用.对比了采用标准k-ε模型和Tam-Ganesan模型对排气系统核心区长度的影响,以及由此引起的排气系统红外辐射特性的变化.通过与试验数据对比证明了该结果的准确性,结果表明选择合适的湍流模型对计算排气系统红外辐射特性有重要的意义.

Numerical simulation of infrared radiation characteristic of exhaust system using Tam-Ganesan turbulence model

The infrared signature in 3～5 μm band of an axisymmetric nozzle was calculated by a three-dimensional code to investigate the improvement of Tam-Ganesan turbulence model in the infrared radiation(IR) of aircraft exhaust system.The flow fields of nozzle were simulated by the finite volume method(FVM),coupled with the standard k-ε turbulence model and Tam-Ganesan model respectively.The infrared signature of the exhaust system was calculated by FVM in non-gray absorbing-emitting media coupled with narrow band model(NBM).The final infrared signature has considered the atmosphere effect.A standard k-ε model was also investigated by being compared with the Tam-Ganesan turbulence model.The Tam-Ganesan turbulence model provided improved mean flow and infrared radiation predictions related to the standard model.It is shown the application of the optimal turbulence model is vital to the calculation of infrared radiation characteristics of exhaust system.