用可变扩散湍流模型研究轴对称排气系统红外辐射特性

Investigation of Infrared Radiation Characteristic of Axisymmetric Exhaust System Using Variable Diffusion Turbulence Model

关键词:  可变扩散  湍流模型  轴对称排气系统  红外辐射 

Key words:  Variable diffusion  Turbulence model  Axisymmetric exhaust system  Infrared radiation

摘要:

为研究可变扩散湍流模型在排气系统红外辐射特性计算中的适用性,计算了轴对称亚声速喷管在3~5μm波段的空腔-喷流组合红外辐射特性。喷管流场及温度场采用有限体积法求解N-S方程,湍流模型采用标准k-ε模型和可变扩散模型。红外特性计算采用有限体积法求解吸收-发射性介质条件下的三维辐射传输方程,并考虑大气衰减作用。计算结果与试验对比表明,与标准k-ε模型相比,可变扩散湍流模型能够有效改善亚声速热喷流的核心区长度,从而获得与试验结果一致的红外辐射强度,说明可变扩散湍流模型适用于精确模拟轴对称排气系统的红外辐射特性。 

Abstract:

The infrared radiation in 3~5μm band of an axisymmetric subsonic nozzle was calculated by a 3-D infrared radiation (IR) code to investigate the improvement for variable diffusion (Var-D) turbulence model in the IR of exhaust system. The 3-D flow fields of nozzle were simulated by the finite volume method (FVM), coupled with the standard k-ε turbulence model and the Var-D model, respectively. The IR signal was calculated by FVM in non-gray absorbing-emitting media, with the atmosphere effect on IR considered. The results show that the Var-D model provides improved hot jet potential core length compared with the standard one and the IR intensity is consistent with the experiment. It demonstrates that the Var-D turbulence model is appropriate for the accurate simulation of IR characteristics of axisymmetric exhaust system.