Improvement of a three-band radiation model for application to chemical nonequilibrium flows

A new strategy to evaluate one important parameter that is used in the radiation model is proposed in order to apply the three-band model to a wider range of flow conditions, including atmospheric entry flows. The proposed model is applied to the reentry conditions of the Hayabusa capsule and its validation. The results obtained generally showed good agreement with those derived by the line-by-line (LBL) method, which is recognized as an accurate method for wavelength integration. In addition, the computational cost of the nonequilibrium three-band model was confirmed to be considerably lower than that of the LBL model. The present nonequilibrium three-band model using the new parameter showed that the prediction accuracy was successfully maintained. The model performance in the region far from the wall was considerably improved when compared with that of the model using a constant value for the parameter.