Research On Extinction Performance And Dynamics Properties Of IR Interference Materials In Vacuum

The IR radiation transmission character in vacuum and interaction mechanism withmaterial are analyzed systematically, the extinction performance of IR interferencematerials in vacuum is computed by Mie theory and T-matrix method, results show that theparticles radius parameter tend to a certain value when the extinction performance is thebest; for the interference materials particle with a invariable volume, the extinction abilityof the particles with needle and flake shape, high shape-change and roughness extent, andbigger true and false part of the refractive index is better. The IR absorption and reflectionperformance of material are also studied, results show that the extinction performance isincreased with the increasing of the conductivity of interference materials.The effect of vacuum degree change on extinction performance of IR interferencematerials is studied experimentally, combining to the vacuum jar experiments, the optimalsoot anti-IR smoke composition and powder interference materials in a certain vacuumdegree condition are optimized, the average transmittance of soot smoke at 3～5μm and8～12μm is about 1.2% and 2.7%, and of graphite smoke at 1～14μm is about 0.1%,which both less than the normal results, and the effect of vacuum degree change on thelong wave IR extinction performance is greater.Basing on the gas-solid two-phase flow and explosive dynamics theory, the expandingmodel of smoke cloud in high vacuum is established; the velocity character of the smokeparticles in forming phase is analyzed by calculated results, results show that pyrotechnicand spray dispersion IR interference materials possess the condition of forming stablesmoke cloud in high vacuum. By revising of the Stokes resistance formula, the dynamicsproperties of smoke particles after smoke formed in vacuum are researched, results showthat the smoke particles sedimentation, diffusion, and coagulation process in vacuum areintensified, and the smoke particles movement law and equations are deduced.The effect of vacuum and microgravity on smoke system is analyzed systematically,the smoke particles interval function model is established by Maxwell speed distributionlaw of gaseous molecular; the effect of smoke particles size and density on the smokestability is discussed by calculated results, results show that the increasing particles sizeand density make the smoke duration prolonged. The smoke pure diffusion model isestablished elementarily by diffusion law, and the estimating method of smoke efficiencyshield area and shield time is obtained.