助推段火箭发动机喷焰红外辐射特性数值计算

Rocket engine exhaust plume during the boost phase is a main object captured by space-based infrared early warning systems due to its significant infrared radiation features. A tripropellant solid rocket engine is taken as the research object. The calculation models of exhaust plume flow fields in continuous and rare regimes are established. The flight trajectory is determined considering the two-stage boost phase. The design parameters of engines are evaluated by the reverse optimization method, and the calculation of flow field is simplified by using an equivalent single nozzle method. The infrared radiation characteristics of rocket exhaust plume are predicted based on the statistical narrow band method and the line-of-sight approach. The results show that the afterburning effect makes the infrared radiation intensity of the plume increase by about 20 times and the in-band radiance increase by about 10 times. There exist two characteristic peaks in 2. 7 μm and 4. 3 μm bands in the infrared spectrum of exhaust plume. The spectral intensity of low-altitude exhaust plume is relatively high, and the integrated intensity within different spectral bands exhibits fluctuation patterns and trough region with the increase in altitude. The difference of the in-band radiances of exhaust plume in the boost phase is up to three orders of magnitude, especially in 4. 3 μm band. This work can provide a theoretical reference for the detection and recognition of rocket in the boost phase.