Experimental and numerical investigation of catalytic efficiency of atomic oxygen recombination on TPS surfaces

The catalytic efficiency of atomic oxygen recombination on silicon carbide is evaluated in the surface temperature range from 300 to 1450 K at the total pressure of 11 Pa by experimental and numerical approaches. In the experiment, the oxygen-argon inductively coupled plasma test flow is generated, and the spatial distribution of emission intensities of atomic oxygen and argon is obtained by optical emission spectroscopy. From the obtained results, the catalytic efficiency is evaluated by actinometry. It is found that the catalytic efficiency increases as the surface temperature increases and the total pressure decreases. Furthermore, the thermochemical nonequilibrium computational fluid dynamics simulation considering the simple catalytic recombination process based on the kinetic theory is carried out to reproduce the flowfield in the test chamber. It is found that the measured emission intensity ratio is reproduced by slightly changing the experimentally deduced catalytic efficiency value. The uncertainties in the results are discussed, and improvements are proposed.