Accession Number : ADA506390


Title :   Experimental/Computational Approach to Accommodation Coefficients and its Application to Noble Gases on Aluminum Surface (Preprint)


Descriptive Note : Journal article Preprint


Corporate Author : AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE


Personal Author(s) : Selden, Nathaniel ; Gimelshein, Natalie E ; Gimelshein, Sergey F ; Ketsdever, Andrew


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a506390.pdf


Report Date : 03 Feb 2009


Pagination or Media Count : 26


Abstract : A technique is proposed to assess gas-surface accommodation coefficients. The technique utilizes the fact that radiometric forces exerted on heated objects immersed in rarefied gases are governed by the interaction of gas molecules with the surface. In the present implementation, it connects measurements of radiometric forces on a heated vane in the transitional flow regime with the kinetic modeling of the flow, and derives the accommodation coefficients through the successive analysis of measured and computed results. A new combined ES-BGK / DSMC approach that allows accurate and time efficient analysis of radiometric forces on a vane in large vacuum chambers filled with rarefied gas is presented. Accommodation coefficients for the Maxwell model are estimated for argon, xenon, and helium on a machined aluminum surface, and found to be 0.81, 0.86, and 0.53, respectively.


Descriptors :   *RAREFIED GASES , *ALUMINUM , *SURFACES , *KINETICS , EFFICIENCY , VACUUM CHAMBERS , COEFFICIENTS , KINETIC ENERGY , TRANSITIONS , HELIUM , MAXWELLS EQUATIONS , ARGON , XENON , ACCURACY , TIME SERIES ANALYSIS , MOLECULES , EXPERIMENTAL DATA , INTERACTIONS


Subject Categories : Fluid Mechanics
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE