Experimental Study of Graphite Ablation in Nitrogen Flow

摘要

The speed of nitridation reaction at a graphite surface is evaluated in an inductively coupled plasma heated wind tunnel. A high-temperature nitrogen plasma flow is generated and a graphite rod is heated by the high-temperature nitrogen flows in the test section of the wind tunnel. The amount of mass loss and the surface temperature of the graphite rod are measured during the experiments. The value of the atomic nitrogen number density striking onto the graphite rod is estimated by calculating the flowfield around the graphite rod without accounting for the nitridation at the graphite surface. The speed of nitridation is deduced from the amount of mass loss rate, the surface temperature, and the atomic nitrogen number density. The results show that the speed of nitridation reaction is about 0.003 for the surface temperature of about 1900 K. The uncertainties in the results are discussed and improvements are proposed.