Experimental Study of Graphite Ablation in Nitrogen Flow, Part II: Further Numerical Analysis

Abstract

DOI: 10.2514/1.43264 The ablative behavior of graphite heated in an inductively coupled plasma wind tunnel is analyzed using an integrated computational method to examine the probability value of nitridation reaction occurring at graphite surface. In this method, the plasma torch freestream condition at the entrance of the test chamber is evaluated by calculating the flows in the plasma torch. The thermal response of the graphite test piece is calculated by loosely coupling the thermochemical nonequilibrium fluid dynamics code and two-dimensional heat conduction equation solver using the freestream condition so valuated. Using a computational tool, surface contours of the graphite test piece at several time steps are calculated by varying the probability value of nitridation reaction and are compared with those measured in the heating test. The effect of impurities remaining in the test chamber is also taken into account.Asaresultofthestudy,itissuggestedthataprobabilityvalueof0.003fornitridation reactionisreasonable to explain the amount of mass loss of the graphite test piece in the heating test.