Characterization of non-equilibrium hypersonic flows using maximum entropy linear model

Maitreyee P. Sharma, Alessandro Munafò, Marco Panesi

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

Abstract

This work proposes a general framework for developing reduced-order models (including both kinetics and transport) for hypersonic flows in thermo-chemical non-equilibrium. Reduced-order modeling is achieved by lumping energy states in groups and by prescribing withing each group a local representation which maximizes the entropy under constraints of mass and energy conservation (Maximum Entropy Linear model; MEL). The governing equations for the group parameters are obtained by taking energy moments of the master equations. Applications consider the complexity reduction of the O2 molecule vibrational kinetics. The accuracy of the MEL model is assessed via comparison with State-to-State predictions in two cases: (i) isothermal chemical reactor (dissociating case) and (ii) Lagrangian nozzle flow (recombining case). In both circumstances results show an excellent agreement with the master equation solution. The MEL is then applied to simulate the steady axi-symmetric viscous flow within a nozzle. Results underline the importance of a proper characterization of non-equilibrium re-combination within nozzles in high-enthalpy wind tunnels. To the author's best knowledge, this case marks the first attempt of integration of a self-consistent reduced-order model (i.e., MEL model) in a CFD solver for non-equilibrium flows.

Original languageEnglish (US)
Title of host publication31st International Symposium on Rarefied Gas Dynamics, RGD 2018
EditorsDuncan Lockerby, David R. Emerson, Lei Wu, Yonghao Zhang
PublisherAmerican Institute of Physics Inc.
ISBN (Electronic)9780735418745
DOIs
StatePublished - Aug 5 2019
Event31st International Symposium on Rarefied Gas Dynamics, RGD 2018 - Glasgow, United Kingdom
Duration: Jul 23 2018Jul 27 2018

Publication series

NameAIP Conference Proceedings
Volume2132
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference31st International Symposium on Rarefied Gas Dynamics, RGD 2018
CountryUnited Kingdom
CityGlasgow
Period7/23/187/27/18

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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