Event Title

Carbon-Phenolic-In-Air Chemistry Model for Atmospheric Re-Entry

Start Date

1-3-2011 8:00 AM

End Date

3-3-2011 12:30 PM

Description

Recent and future re-entry vehicle designs use ablative material as the main component of the heat shield of their thermal protection systems. In order to properly predict the behavior of the vehicle, it is imperative to take into account the gases produced by the ablation process when modeling the reacting flow environment. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled in the boundary layer is complex and might lead to thermo-chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain better predictions, a proper gas flow chemistry model needs to be included in the CFD calculations. Recent calculations showed that extensive differences were found in boundary layer composition and heat fluxes, both convective and radiative, when previously published models were used. Recently, a more complete model was proposed, which includes an extensive set of kinetic rates, taken from the combustion community. Using this model, CFD calculations of the Stardust re-entry are presented. The results clearly demonstrate the need to account for many more species in the flow field than the ones that are expected to be present at the surface. The results are then used to obtain non-equilibrium radiation spectral data, which are compared to the experimental data obtained during Stardust re-entry by the Echelle instrument.

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Mar 1st, 8:00 AM Mar 3rd, 12:30 PM

Carbon-Phenolic-In-Air Chemistry Model for Atmospheric Re-Entry

Recent and future re-entry vehicle designs use ablative material as the main component of the heat shield of their thermal protection systems. In order to properly predict the behavior of the vehicle, it is imperative to take into account the gases produced by the ablation process when modeling the reacting flow environment. In the case of charring ablators, where an inner resin is pyrolyzed at a relatively low temperature, the composition of the gas expelled in the boundary layer is complex and might lead to thermo-chemical reactions that cannot be captured with simple flow chemistry models. In order to obtain better predictions, a proper gas flow chemistry model needs to be included in the CFD calculations. Recent calculations showed that extensive differences were found in boundary layer composition and heat fluxes, both convective and radiative, when previously published models were used. Recently, a more complete model was proposed, which includes an extensive set of kinetic rates, taken from the combustion community. Using this model, CFD calculations of the Stardust re-entry are presented. The results clearly demonstrate the need to account for many more species in the flow field than the ones that are expected to be present at the surface. The results are then used to obtain non-equilibrium radiation spectral data, which are compared to the experimental data obtained during Stardust re-entry by the Echelle instrument.