Accurate evaluation on infrared spectral radiation for booster phase rocket exhaust plumes

Accurate modeling of rocket exhaust plumes' infrared spectral radiation is of great significance in the field of aerospace. The existing classical statistical-narrow-band (SNB) model cannot adapt well to the highly heterogeneous plume temperature and concentration fields, with large radiation modeling errors at the spectral level. To overcome this limitation, this study presents an improved SNB model (I-SNB) for rocket plume infrared spectral radiation modeling, which categorizes the spectral lines within narrow band & UDelta;& eta; into different groups according to their inconsistency in sensitivity to changes in both temperature and concentration along the plume integration path, ensuring that the spectral lines within the same group have similar behaviors with simultaneous changes in both temperature and concentration. The modeling accuracy of the present I-SNB model has been evaluated using FTIR spectral measurements and LBL benchmark solutions, demonstrating significantly better performance than the classical SNB model. Then, the I-SNB model has been used to investigate the rocket plume spectral radiation during the booster phase, the results of which have engagement guiding significance for the development of booster phase interception (BPI) of the space-based infrared early warning system.