A method to determine the domain of a rocket exhaust plume

Aimed at calculating the infrared radiation of a rocket exhaust plume exactly and efficiently, a method for defining the domain of an exhaust plume was reported. As a basic work, the flow field was calculated by using the CFD software FLUENT, and the radiation was calculated by means of Finite Volume Method (FVM). Then, variables that might be able to be used to differentiate an exhaust plume from surrounding atmosphere such as temperature and species composition were studied and the mass fraction of CO was chosen. When calculating the infrared radiation of an exhaust plume, only the part where the CO mass fraction bigger than the threshold was taken into account, and the rest were neglected. The change law of size of calculation domain, calculation time and infrared radiation with thresholds were studied. The results show that, as the threshold decreases, the size of calculation domain and the calculation time increase monotonously and rapidly, while the infrared radiation changes a lot at first and becomes stable at last. Besides, it was indicated by simulation experiments that the CO mass fraction 0.000 5 as the threshold is acceptable to define the calculation domain of the exhaust plume.