Species and Temperature Gradient Measurements in the Reacting Boundary Layer Over ICP Test Samples

Improved estimations of stagnation point heat transfer require more physically realistic gas-surface interaction models. This paper reports on the ongoing development of spatially resolved laser diagnostic measurements of key reacting species in the thermal boundary layer over material samples placed in the flow of an inductively coupled plasma torch facility in stagnation point configuration. The specific case of carbon extraction from graphite by atomic nitrogen (nitridation) is used to illustrate the methodology, which provides translational temperature and species concentration along the stagnation stream-line. These measurements are used to make a preliminary estimate of the nitridation rate for graphite surface temperature of 1590 K.