Numerical simulation on the infrared characteristic of the jet plume of a solid rocket motor

Solid propellant is widely used as the fuel in solid rocket motor, providing thrust for the aircraft power plant. It has the advantages of simple structure, convenient use, good maneuverability, high reliability, high quality, long-term storage and in combat readiness status. Based on the Euler-Lagrangian method, the gas-solid two-phase plume flow field considering the post-combustion chemical reaction is calculated. Besides, secondary combustion can significantly enhance the infrared radiation of the plume. The results show that the afterburning reaction can improve the temperature of plume flow field, increase the mass fraction of CO₂ and H₂O, and enhance the infrared radiation intensity of plume. Some solid propellants with aluminum powder, in the combustion process, will produce Al2O₃ particles, and Al2O₃ particles have strong infrared radiation, greatly enhanced the plume infrared radiation intensity. The temperature change lags behind the gas flow field, and produces further heating to the flow field. The results show that the particle phase can increase the temperature of the first Mach platoon and improve the infrared radiation intensity of the plume. With the increase of particle content, the peak temperature of plume increased and the intensity of infrared radiation increased. The results show that the intensity of infrared radiation in the plume increases with the decrease of the scale factor. What's more, it is necessary to analyze the feathers in different flight conditions and different velocity and the infrared characteristics of the plume. In this paper, the plume and infrared radiation characteristics of pure gas plume and particle plume at different heights (35 km, 40 km, 45 km, 50 km) are calculated respectively. The results illustrate that plume expansion is more intense with the increase of height, the influence area of plume is enlarged, the peak temperature of plume decreases, the afterburning reaction is restrained, the movement range of particle is enlarged and the effect of particle on flow field temperature decreases. The effect of radiation source on the plume temperature is increased, and the intensity of infrared radiation is reduced, but the influence range is expanded. At the same time, the plume and infrared radiation characteristics of plume under different velocity (0.5 Ma, 1 Ma, 1.5 Ma, 2 Ma) were studied. The results show that with the increase of velocity, the influence area of plume decreases, the peak temperature of plume decreases, the post combustion reaction decreases, the particle motion is inhibited, the effect of particles on flow field decreases, and the intensity of infrared radiation decreases.