湍流模型对发动机排气系统流场和红外辐射特征计算的影响

计算分析了采用k-ω SST(shear-stress transport)模型、RNG(renormalization group)k-ε模型配合标准壁面函数(RNG k-ε+标准壁面函数)、RNG k-ε模型配合增强型壁面函数法(RNG k-ε+增强壁面函数)3种湍流模拟方法,对典型涡扇发动机轴对称收敛喷管排气系统流场、温度场、组分质量浓度场及红外辐射特征计算结果的影响.研究表明:对于这3种方法,排气系统腔体内壁面压力分布基本一致;但在温度场、组分质量浓度分布以及红外辐射特征方面的差别较大.RNG k-ε+增强壁面函数计算得到的内涵壁面与燃气流的温度、CO₂与H₂O的质量浓度和红外辐射强度值最大,RNG k-ε+标准壁面函数的计算结果其次,而k-ω SST 模型的计算结果最小.通过与试验结果对比,发现k-ω SST模型对排气系统红外辐射特征的模拟更加合理一些. 

Effect of turbulence models on numerical simulation of flow and infrared radiation characteristic of aero-engine exhaust system

The flow field and infrared radiation (IR) characteristics of an aero-engine exhaust system were simulated with three turbulence models, including k-ω shear-stress transport (SST) model,renormalization group (RNG) k-ε model with standard wall functions and RNG k-ε model with enhanced wall functions.The results show that among the three methods, the static pressures are nearly the same,but the distributions of temperature,species and IR are different.The temperature of gas and the inner wall of inner duct,the mass concentration of species and IR are the greatest when RNG k-ε model with enhanced wall functions is used;those are the second when RNG k-ε model with standard wall functions is used,and the results of k-ω SST model are minimal.The comparison of experimental data and those of computation shows that the IR results of k-ω SST model are more reasonable.