Research On The Polarized Radiative Characteristics Of Rocket Exhaust Plume

Currently,the fast development in military field has given rise to the climax of aircraft stealth technology,which makes it an urgent task for reasearchers to study in-depth so that more target detection measures can be created.Polarization,as a unique property of transverse waves,has enormous potential of being utalized in detecting targets.This thesis develops a calculation model on the basis of Monte Carlo radiation transport method and Mie scattering theory to analyze the polarization characteristics of three-dimensional inhomogeneous granular media from different aspects.With the model above,a detailed and specific research on the polarization characteristics of a solid rocket exhaust plume can be implemented.Starting from the theory of electromagnetism established by James Clerk Maxwell,the model uses stokes vectors of light as its description tool of polarization.Combined with the Mie scattering theory,this model works accuratly and robustly due to the verification results given in Chapter 2.Investigations on the flow field parameters of the solid rocket exhaust plume reveal the distribution of various substances in this section.The physical and opti cal parameters as well as the distribution data of alumina particles in this section are thus acquired.With these materials,the polarization radiative transfer process is modeled and analyzed.The influence of different factors such as the wavelength and zenith angle on the results is discussed.Then the focus is transferred to the working environment of the solid rocket exhaust plume.Clouds,as the background of the target,should be assessed.After the selection of three typical types of clouds which are stratus,cirrus and altostratus,the polarization radiative transfer with them as medium is modeled and a thorough disccussion about it is carried out.With the ample analysis,several important conclusions are therefore drawed.Taking into account the carbon soot in the target,the ultimate chapter integrates the raw model with effective medium approximations,which makes it possible for the model to calculate compsite materials.Then the thesis takes a close look at the carbon soot properties in the solid rocket plumes.Carbon soot of different volume ratios is separately put into the original exhaust plume and modeled,which grant s the thesis with some final conclusions regarding the inclusion of carbon soot.