Research On Near Field Infrared Radiation Characteristics Of Plume From Solid Rocket Motor

Solid rocket motor is widely used in missiles,launch vehicles and other aircrafts.Infrared radiation is an important signal characteristics of flight vehicles.Therefore,it is significant to pay attention to the infrared radiation signature of the plume,which has a great influence on guiding the stealth design of aircraft,improving the formulation of propellant,and designing the detection system.The main work of this paper is shown as follows:In this paper,the component transport model with law of conservation of energy and aw of conservation of mass is used to calculate the flow field parameters and composition distributions.The Arrhenius law and the H₂/CO reaction system are applied to describe afterburning reactions model;and the discrete particle model which is established by Lagrangian method is adopted to track the movement of Al₂O₃ particles in the plume.The infrared radiation source term is introduced into the energy equation,and the near field infrared radiation signature of the plume is presented by the discrete coordinate method.The effects of afterburning reactions on the flow field were studied.The results show that afterburning reactions have a positive influence on the temperature of plume flow field,the mass fraction of CO₂ as well as H₂O and the infrared radiation intensity of plume.The study on particle show that the particle phase can increase the temperature of the first Mach platoon so as so improve the infrared radiation intensity of the plume.With the increase of particle content,the peak temperature of plume is improved so that the intensity of infrared radiation is increased.What's more,the study on scaling motors reveal that the infrared radiation intensity in the plume increases with the increase of the scaling factor.The plume and infrared radiation characteristics of plume at different heights?35km,40km,45km,50km?were studied.The results show that with the improvement of the height,the affected area of the plume is enlarged,and the peak temperature of the plume decreases,the afterburning reaction is restrained,and the movement range of particles is enlarged,the effect of particles on the flow field is reduced,then the influence of temperature is increased and the intensity of infrared radiation is reduced.The plume and infrared radiation characteristics of the plume under different velocity?0.5Ma,1Ma,1.5Ma,2Ma?were studied.The results explain that with the increase of velocity,the influence area of plume decreases,the peak temperature of plume decreases,and the afterburning reactions decrease,and the particle motion is inhibited,and the effect of particles on flow field decreases,so the intensity of the infrared radiation is reduced.The transmittance of infrared radiation in plume and atmosphere was studied.The theoretical results are in agreement with the experimental data.The infrared radiation has characteristics.The range of 2500 to 3000 cm^-1 is named as atmospheric window because of the comparatively high transmittance in this band.Infrared radiation transmittance decreases with increasing distance,but increases with increasing height.