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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

COUPLED RADIATION EFFECTS FOR EARTH ENTRY FLOWS

Get access (open in a dialog) DOI: 10.1615/IHTC13.p4.40
13 pages

Abstract

A nonequilibrium Navier-Stokes solver has been coupled in a loosely fashion to a radiation transfer solver to develop a numerical tool aiming at helping in the design of appropriate thermal protection systems for atmospheric re-entry vehicles. Radiation properties are computed with a line-by-line approach. Radiation transfer is solved using the tangent slab method. The discrete transfer method is also used for local accurate prediction of the radiative heating and for assessing the tangent slab approximation. The procedure is applied to replicate the Project Fire II experimental data at three trajectory points that encompass flow regimes from large nonequilibrium to equilibrium conditions. Agreement is fair, especially concerning the incident radiative flux as measured by radiometers. Concerning the total surface heating, larger discrepancies are obtained, that are attributed to the flow solver. Indeed, the large influence of the ionization finite chemical rates on the prediction of convective flux has been highlighted. The lack of experimental data at such high temperature regimes makes it difficult to select the appropriate physico-chemical models. Coupling the radiative and hydrodynamic fields improves the computation: it reduces the discrepancies between computed and flight data. Besides, compared to the discrete transfer method, the tangent slab approximation overestimates the radiation heating by 15% to 20%, which is close but below the measurement uncertainty. Radiation participates in the vehicle surface heating by up to 32%.