摘要 :
Recently, there has been increased interest in improving models of ablative thermal protection systems by treating the materials and fluid behavior in a coupled manner. The present paper reports a new approach to modeling the inte...
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Recently, there has been increased interest in improving models of ablative thermal protection systems by treating the materials and fluid behavior in a coupled manner. The present paper reports a new approach to modeling the interface between fluid and material, with attention paid to the conservation of species mass flux and energy on the fluid side of the interface. The general equation is presented and is shown to recover the traditional uncoupled fluid/materials response interface. Including the chemical reaction terms on the CFD side of the interface makes the heat flux exchange independent of the thermodynamic reference state and, therefore, a measurable quantity. Doing so allows the material response solver to take as input the surface heat flux instead of a film coefficient - the traditional approach. Removing the film coefficient approximation enables more direct solution of vehicle thermal response but requires consistency in the wall state. The mixing of the shock layer and pyrolysis gas mixture is then computed with finite-rate chemistry within the fluid solver. The boundary conditions described have been implemented in v4.05.1 of the CFD code DPLR. Char removal is captured using finite rate chemistry in DPLR's gas surface interaction module. Aspects of coupling these solutions to material response are discussed. The reformulated boundary condition provides a simplified formalism for exchanging coupling data without introducing inconsistencies between CFD and Material solvers that may employ different thermodynamic source data.
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摘要 :
We study the gas-surface interaction of dissociated air in a high enthalpy flow. A framework that provides proper gas-surface interaction boundary conditions for any flow solver has boon developed in the Mutation++ library of the ...
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We study the gas-surface interaction of dissociated air in a high enthalpy flow. A framework that provides proper gas-surface interaction boundary conditions for any flow solver has boon developed in the Mutation++ library of the von Karman Institute for Fluid Dynamics (VKI). It solves the mass and energy balances at the wall taking into account catalysis and ablation. Two different catalytic models are currently available in the code: a phenomenological one called "γ model" and a finite-rate chemistry one. For ablation a phenomenological model for solid carbon ablators has been implemented including the three processes of oxidation, nitridation, and sublimation. The aforementioned models were used to simulate the experiments performed in the high enthalpy Plasmatron wind tunnel of VKI and the numerical results were compared to the experimental data. In the first experiment, a copper flat plate was placed in the plasma jet in order to assess its catalytic properties at off-stagnation point conditions. In the second one, the behaviour of a carbon fiber lightweight ablator was tested. The flow field was modeled by the single temperature multi-species Navier-Stokes equations in chemical non-equilibrium and solved with the finite volume code Cosmic.
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摘要 :
We study the gas-surface interaction of dissociated air in a high enthalpy flow. A framework that provides proper gas-surface interaction boundary conditions for any flow solver has boon developed in the Mutation++ library of the ...
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We study the gas-surface interaction of dissociated air in a high enthalpy flow. A framework that provides proper gas-surface interaction boundary conditions for any flow solver has boon developed in the Mutation++ library of the von Karman Institute for Fluid Dynamics (VKI). It solves the mass and energy balances at the wall taking into account catalysis and ablation. Two different catalytic models are currently available in the code: a phenomenological one called "γ model" and a finite-rate chemistry one. For ablation a phenomenological model for solid carbon ablators has been implemented including the three processes of oxidation, nitridation, and sublimation. The aforementioned models were used to simulate the experiments performed in the high enthalpy Plasmatron wind tunnel of VKI and the numerical results were compared to the experimental data. In the first experiment, a copper flat plate was placed in the plasma jet in order to assess its catalytic properties at off-stagnation point conditions. In the second one, the behaviour of a carbon fiber lightweight ablator was tested. The flow field was modeled by the single temperature multi-species Navier-Stokes equations in chemical non-equilibrium and solved with the finite volume code Cosmic.
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摘要 :
1.Icarus is a multi-dimensional, unstructured material response solver 1.1 Design applications: heatshield sizing, uncertainty quantification 1.2 Material model validated against experimental data 2. Actively maintained and is bei...
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1.Icarus is a multi-dimensional, unstructured material response solver 1.1 Design applications: heatshield sizing, uncertainty quantification 1.2 Material model validated against experimental data 2. Actively maintained and is being used as a part of several NASA missions 2.1 Dragonfly, Mars Sample Return, etc. 3. Current / Future development timeline 3.1 Validation (always on-going) and Software Refinement / Profiling 3.2 Additional physics as requested by users 3.3 Multi-physics coupling (Flow + Radiation + Material).
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