Modeling of Interactions of Ablated Plumes
Final rept. 15 Jun-30 Nov 2007
AKRON UNIV OH
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Heat transfer modulation between the gas flow and the Thermal Protection Shield TPS that occurs because of ejection of under-expanded pyrolysis gases through the cracks in the TPS is studied by numerical modeling. The simulations are performed for an axisymmetric bluff body flying at Mach 7. The influence of the geometry of the TPS on heat transfer pattern was studied for two representative shapes. The results are presented for three different flight altitudes low-ground level, moderate-20km and high-30km. At the low altitude the plume pressure is lower than the pressure behind the detached front shock wave and the plume propagates slowly along the wall surface. At high and moderate altitudes, the plume path and consequently, convective heat transfer between the TPS and the plume depends on the plume interaction with the bow shock wave. The effect of initial pressure of pyrolysis gas on the plume dynamics is significant. The presence of the blast wave associated with under-expanded plume alters the heat transfer and increases mixing. Finally, the enhanced heat transfer caused by the emergence of multiple plumes is investigated.
- Fluid Mechanics