Computational Study of Impregnated Ablator for Improved Magnetohydrodynamic Heat Shield

Abstract

A dipole magnet was used to locally reduce surface heating on a fin that extended from a blunt elliptic cone geometry traveling in air at hypersonic speeds. The concept relies on magnetohydrodynamics to generate a force in the weakly ionized postshock air, which decelerates the incoming flow. A three-dimensional, compressible, thermochemical nonequilibrium, fluid code was loosely coupled to a magnetohydrodynamics module to compute the resultant flowfield, which included the electric field. The results showed that the resultant electric field had a minor contributor to the current and consequently to the magnetic body force. In the baseline scenario, the applied magnet was ineffective at perturbing the local shock due to the unseeded flow’s level of electrical conductivity. A potassium-infused ablator was incorporated into the vehicle’s nose to improve the flow’s low electrical conductivity and protect the geometry from the high thermal loads experienced at the stagnation point. A one-dimensional equilibrium material response code was developed and used to model the ablative surface. The seed particles introduced into the fluid domain substantially increased the electrical conductivity of the flow. The resultant magnetic body force moved the triple point up the fin face, which changed the local surface properties to an extent that could be measured in flight.