Start Date
2-3-2011 9:50 AM
Description
An overview is presented of a generalized finite-rate surface chemistry model that has been developed for gas/surface interaction coupling to the Data-Parallel Line-Relaxation (DPLR) code. Species from the gaseous environment are allowed to interact with species adsorbed onto one or more phase of a surface and with one or more phases of a bulk thermal protection system through an arbitrary number of finite-rate reactions. The reactions may include types such as adsorption, desorption, Eley-Rideal recombination, Langmuir-Hinschelwood recombination, partial or total dissociative adsorption, oxidation, reduction, sublimation, or condensation where forward and reverse rates are constrained by thermodynamics. A simple pyrolysis model is incorporated into the gas species mass balance and energy balance boundary conditions where the pyrolysis production may be specified explicitly from an uncoupled material response analysis or assumed steady-state proportionality to the bulk phase ejection rate. The production rates of all gaseous species are implicitly coupled into the viscous wall boundary condition of the DPLR code to maximize the convergence rate of the solver. Examples are shown for a catalysis system and a TPS system to demonstrate the model. The focus of the work presented is primarily to demonstrate the necessary model, reaction, surface, and material data required.
Included in
GSI Modeling Overview: Requirements for Macroscopic Gas/Surface Interaction Coupling to CFD Codes
An overview is presented of a generalized finite-rate surface chemistry model that has been developed for gas/surface interaction coupling to the Data-Parallel Line-Relaxation (DPLR) code. Species from the gaseous environment are allowed to interact with species adsorbed onto one or more phase of a surface and with one or more phases of a bulk thermal protection system through an arbitrary number of finite-rate reactions. The reactions may include types such as adsorption, desorption, Eley-Rideal recombination, Langmuir-Hinschelwood recombination, partial or total dissociative adsorption, oxidation, reduction, sublimation, or condensation where forward and reverse rates are constrained by thermodynamics. A simple pyrolysis model is incorporated into the gas species mass balance and energy balance boundary conditions where the pyrolysis production may be specified explicitly from an uncoupled material response analysis or assumed steady-state proportionality to the bulk phase ejection rate. The production rates of all gaseous species are implicitly coupled into the viscous wall boundary condition of the DPLR code to maximize the convergence rate of the solver. Examples are shown for a catalysis system and a TPS system to demonstrate the model. The focus of the work presented is primarily to demonstrate the necessary model, reaction, surface, and material data required.
Notes
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