Modeling Of The Ultraviolet Radiation Of Oh/NO In Exhaust Plume And Simulation Of Scattering Properties Of Sunlight

Rocket and missile engines rely on discharging high temperature and high speed exhaust gas to obtain thrust, solid or liquid propellant produce exhaust in the combustion chamber under high pressure. Exhaust plume flowfield have the characteristics of high temperature, high speed and multi-species reacting flow. The radiation mechanism is very complex in the flowfield. UV spectrum of exhaust plume involving complex gaseous kinetic and thermodynamic processes. Exhaust plume UV radiation signal are important basis of diagnosing, detecting and identifying plume spectrum. UV missile warning discovers the target by detecting the UV radiation of missile exhaust plume; therefore, it is of great significance to carry out on the analysis of UV radiation mechanism of engine exhaust plume.This paper mainly concentrates on the UV radiation mechanism of gas composition of rocket and missile engines exhaust plume and atmospheric scattering properties of plume particles.The major research contents are listed as follows:(1) Study on the ultraviolet radiation properties of OH radical in the engine exhaust plume.The ultraviolet radiation mechanism of OH radical in the exhaust plume is studied. The "collision-radiation" model which is used to calculate the non-equilibrium population on different energy levels of OH radical and built up on the basis of "quasi-steady-state" model is validated. On this basis, sensitivity analysis of non-equilibrium finite rate chemical reactions and gas composition involved in the "collision-radiation" model is performed, identifying the key reactions and key components which play a leading role.In the end, the result of "collision-radiation" model is compared with that of local equilibrium chemiluminescenct model and " three passageway" model.(2) Study on modeling the "collision-radiation" model of NO molecule in the engine exhaust plume.The "collision-radiation" model and "steady-state calculation" model used to calculate the parameters of radiation properties of NO molecule chemiluminescenct reactions are established by investigation of the ultraviolet radiation mechanism of NO molecule in the exhaust plume. Due to lack of reverse reaction rate constant of NO molecule sparking reaction, the computing result of "collision-radiation" still needs to be researched further. By result collected by "steady-state calculation" model, the influence of temperature and components on the radiation intensity of NO molecule is analyzed.(3) Study on sunshine UV scattering properties of exhaust plume.Monte Carlo Method is used to simulate sunlight UV scattering properties of exhaust plume flowfield. The influence of different wavelength, different diameters of particles, and different projection direction on sunshine UV scattering properties of exhaust plume is analyzed.