Advancements in afterbody radiative heating simulations for earth entry

Christopher O. Johnston, Marco Panesi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Four advancements to the simulation of backshell radiative heating for Earth entry are presented. The first of these is the development of a flowfield model that treats electronic levels of the dominant backshell radiator, N, as individual species. This is shown to allow improvements in the modeling of electron-ion recombination and two-temperature modeling, which are shown to increase backshell radiative heating by 10 to 40%. By computing the electronic state populations of N within the flowfield solver, instead of through the quasi-steady state approximation in the radiation code, the coupling of radiative transition rates to the species continuity equations for the levels of N, including the impact of non-local absorption, becomes feasible. Implementation of this additional level of coupling between the flowfield and radiation codes represents the second advancement presented in this work, which is shown to increase the backshell radiation by another 10 to 50%. The impact of radiative transition rates due to non-local absorption indicates the importance of accurate radiation transport in the relatively complex flow geometry of the backshell. This motivates the third advancement, which is the development of a ray-tracing radiation transport approach to compute the radiative transition rates and divergence of the radiative flux at every point for coupling to the flowfield, therefore allowing the accuracy of the commonly applied tangent-slab approximation to be assessed for radiative source terms. For the sphere considered at lunar-return conditions, the tangent-slab approximation is shown to adequately model the radiative source terms, even for backshell cases. This is in contrast to the agreement between the two approaches for computing the radiative flux to the surface, which being more sensitive to non-local emission, differ by up to 40%. The final advancement presented is the development of a nonequilibrium model for NO radiation, which provides significant backshell radiation at velocities below 10 km/s. The developed model reduces the nonequilibrium NO radiation by 50% relative to the previous model.

Original languageEnglish (US)
Title of host publication46th AIAA Thermophysics Conference
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624104350
StatePublished - Jan 1 2016
Event46th AIAA Thermophysics Conference, 2016 - Washington, United States
Duration: Jun 13 2016Jun 17 2016

Publication series

Name46th AIAA Thermophysics Conference

Other

Other46th AIAA Thermophysics Conference, 2016
CountryUnited States
CityWashington
Period6/13/166/17/16

ASJC Scopus subject areas

  • Aerospace Engineering
  • Mechanical Engineering

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