A numerical simulation on the infrared radiation of hot exhausting nozzles with a coupled flow and heat transfer model

A coupled model among flow field, solid temperature, species concentration and gas radiation, which was based on statistical narrow-band correlated-k model, was employed to predict the infrared radiations from hot exhausting nozzles. The parameters of narrow-band model were deduced from HITEMP line-by-line database. Several methods to increase computational efficiency and to save computational resources were employed, thus all the complicated computations could be operated on a personal computer. The predictions for three cases have been conducted to validate the accuracy of the methods mentioned above, including the temperature distribution of a water-cooling nozzle in rocket engines, the carbon dioxide absorptivity at the wavelength of 4.3 micron and the infrared radiation of a cylindrical furnace. Finally, the aerothermodynamic and infrared characteristics of two nozzles were predicted. It was shown that the infrared radiation intensity of chevron ejecting nozzle were obviously smaller than that of common axisymmetric convergent-divergent nozzle.