Modeling of Crack Propagation in AVCOAT, a Charring Ablator
Start Date
1-3-2011 8:00 AM
End Date
3-3-2011 12:30 PM
Description
Objective of this work is to estimate the potential growth of a tapered crack on an AVCOAT ablative TPS in the arcjet environment and in flight. To accomplish this objective, we have developed a simple one-dimensional model of pyrolysis blowing rates for AVCOAT which allowed us to determine the maximum chemical ablation rate in the arcjet and along a reentry trajectory. The research was done in four stages. First solutions of the arcjet flow over a crack specimen were obtained. In addition, flow solutions over the CEV module for a range of altitudes, varying from 100 to 70 km were performed. From these simulations, the heat flux was estimated at the stagnation point/crack inlet and the AVCOAT material thermal response was calculated to estimate the pyrolysis gas flow rate emitted by the walls of a tapered crack tile. Finally the interaction of the boundary layer gases in the crack channel with the pyrolysis gases was studied. Chemical ablation along the channel surface was computed at various altitudes.
Modeling of Crack Propagation in AVCOAT, a Charring Ablator
Objective of this work is to estimate the potential growth of a tapered crack on an AVCOAT ablative TPS in the arcjet environment and in flight. To accomplish this objective, we have developed a simple one-dimensional model of pyrolysis blowing rates for AVCOAT which allowed us to determine the maximum chemical ablation rate in the arcjet and along a reentry trajectory. The research was done in four stages. First solutions of the arcjet flow over a crack specimen were obtained. In addition, flow solutions over the CEV module for a range of altitudes, varying from 100 to 70 km were performed. From these simulations, the heat flux was estimated at the stagnation point/crack inlet and the AVCOAT material thermal response was calculated to estimate the pyrolysis gas flow rate emitted by the walls of a tapered crack tile. Finally the interaction of the boundary layer gases in the crack channel with the pyrolysis gases was studied. Chemical ablation along the channel surface was computed at various altitudes.