Atomic Oxygen Recombination and Chemical Energy Accommodation on Alumina at High Temperature

Abstract

To develop heat shields for space vehicles, materials must be characterized in simulation conditions close to those in space environments. The most important conditions for simulating the Earth re‐entry phase of space vehicles are achieved through the MESOX set‐up associating a 6 kW solar radiation concentrator and a 2450 MHz microwave plasma generator. This paper presents some experimental results for the recombination coefficient γ and the chemical energy accommodation coefficient β in the surface‐catalyzed oxygen atom recombination based on experiments performed on the MESOX set‐up. This set‐up allows both the experimental measurements of the recombination coefficient γ using Optical Emission Spectroscopy and the chemical energy accommodation coefficient β using calorimetry according to a defined protocol. Experimental results are presented for three types of alumina in the temperature range 900–2400 K, for 200 Pa total air pressure. These three alumina differ essentially from their content of sintering additives.