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.