Measurements of emission spectra from a shock layer of a blunt body in arc-heated gas

Arcjet tests were conducted to investigate the catalytic effects of two types of thermal protection coating having different surface catalytic efficiencies. One is BHE (black high emittance) coating with lower catalytic efficiency, the other is RF (reference) coating with higher catalytic efficiency. Experiments consist of the measurements of emission spectra from the shock layer of the model and heat flux to the model. As a working gas, a mixture of 80 % N2 and 20 % 62 by volume was used in the tests. Spectroscopic measurements showed that the difference of catalytic efficiency between the two coatings slightly appeared on oxygen atomic spectra. The spectral intensities of atomic oxygen measured for the RF model were slightly smaller than those for the BHE model. In addition, time-averaged heat fluxes into the models were measured and the results showed that heat flux into the RF model was larger than that into the BHE model by 5.2 %.