Numerical analysis of infrared radiation intensity of two-dimensional convergent divergent exhaust system considering the effects of multiple components

Abstract

With the development of computer technology, coupled simulation of multiple components has gradually gained attention. This paper focuses on an integrated model consisting of turbine, afterburner, and two-dimensional convergent divergent (2D-CD) nozzle. The multi-scale multi-group wideband k-distribution model (MSMGWB) was employed to calculate spectral transmittance, and wall emissivity was determined through experiments. The paper quantitatively analyzes the difference in infrared radiation (IR) intensity obtained from traditional computational methods compared to the integrated model, investigates the impact of turbine outlet swirl flow on infrared characteristics, and finally reveals the effects of low-emissivity coatings and turbine cooling on the infrared intensity of the integrated model. The results show that the turbine and afterburner have significant influence on the infrared characteristics of the exhaust system, which can't be ignored in the study. When the turbine is ignored, the IR intensity decreases by up to 8.7 % under swirl flow condition, while the IR intensity decreases by up to 9.7 % without swirl flow condition. If the infrared characteristics of turbine and afterburner are ignored, the IR intensity can decrease by 22.1 % at most and increase by 412.4 % at most. Cooling measures for turbine blades can significantly reduce the infrared intensity. When the turbine temperature is reduced by 240 K, the infrared intensity decreases by up to 28.4 %. Low emissivity measure for turbine structure has limited influence on infrared intensity. Applying low-emissivity measures to the afterburner high-temperature walls, the infrared radiation intensity can be reduced by up to 34.2 %. By combining all the effective infrared suppression measures mentioned above, the infrared intensity of the integrated model can be reduced by up to 53.1 %.