Wall Catalytic Recombination and Boundary Conditions in Nonequilibrium Hypersonic Flows — with Applications

Scott, Clayton

doi:10.1007/978-1-4612-0371-1_6

Cited by 9 publications

(1 citation statement)

References 55 publications

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“…For the simulation of the full range of catalycity regimes, from a noncatalytic wall to a fully catalytic wall, a simplified catalytic atom recombination model (i.e., a binary interaction model with full energy accommodation [35]) is implemented in LeMANS. It is a simple model applied to a binary gaseous mixture of atoms and molecules of the same species.…”

Section: Binary Catalytic Recombination Modelmentioning

confidence: 99%

Numerical Analysis of Surface Chemistry in High-Enthalpy Flows

Anna

Boyd

2015

Journal of Thermophysics and Heat Transfer

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The effects of surface-chemistry processes of a graphite sample exposed to a subsonic high-enthalpy nitrogen flow are investigated using a coupled computational fluid-dynamics/surface-chemistry model. The results obtained are assessed for the accuracy of the model using experimental data from tests conducted in a 30 kW inductively coupled plasma torch facility at the University of Vermont. Significant discrepancies are observed between the computational and experimental results. Therefore, a study is performed to determine sensitivities of flow and surface parameters to variations in testing input conditions, as well as physical modeling parameters. Measurements of the absolute number density are required to draw firm conclusions about the surface-chemistry models, as well as the surface reactions involved.Nomenclature C k = concentration of gas species k, mol∕m 3 D k = diffusion coefficient of species k, m 2 ∕s E ad = energy barrier for adsorption, J∕mol E ER = energy barrier for Eley-Rideal recombination, J∕mol h = species enthalpy, J∕kg K = total number of species K g = total numbers of gas species K nb = number of species in bulk phase nb K ns;na = number of species in active site set na on surface phase ns k B = Boltzmann constant k fi , k bi = forward and backward reaction rates for reaction i M k = molar weight of species k, kg∕mol _ m b = mass blowing rate due to surface reactions, kg∕m 2 ∕s N = total number of phases N nb = number of bulk species N g , N s , N b = number of gas, surface, and bulk phases N ns;a = number of active site sets in surface phase ns N R = number of surface reactions P = pressure, Pa q = total heat flux, W∕m 2 q conv = convective heat flux, W∕m 2 q diff = diffusive heat flux, W∕m 2 R u = universal gas constant, J∕mol∕K r i;ns = reaction flux of reaction i on surface phase ns, mol∕m 2 ∕s S, S 0 = sticking coefficient T = translational-rotational temperature, K ν ki = net stoichiometric coefficient for species k in reaction i ν s = sum of the stoichiometric coefficients of all surface reactants ν k = thermal speed of gas-phase species k, m∕s ν 0 ki = reactant stoichiometric coefficient for species k in reaction i ν 0 0 ki = product stoichiometric coefficient for species k in reaction i _ w k = production rate of species k in all reactions, mol∕m 2 ∕s _ w ki = production rate of species k in reaction i, mol∕m 2 ∕s, Y = mass fraction Γ k = impingement flux of gas species k, m 2 ∕s γ = reaction efficiency θ ns;k = fraction of active sites occupied by species k on surface phase ns ρ = density, kg∕m 3 σ = Stefan-Boltzmann constant, W∕m 2 ∕K −4 Φ ns = active site density on surface phase ns, mol∕m 2 Φ ns;k = concentration of species k on surface phase ns, mol∕m 2 χ k = mole fraction of species k χ nb;k = mole fraction of bulk species k in bulk phase nb Subscripts b = bulk phase e = empty site g = gas phase na = number of active sites nb = number of bulk phases ns = number of surface phases s = surface phase tr = translational-rotational energy mode ve = vibrational-electronic energy mode...

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Section: Binary Catalytic Recombination Modelmentioning

confidence: 99%