Spectroscopic Analysis of Shock Layer Flows in a High Enthalpy Arcjet Facility

摘要

1.Introduction When a space vehicle enter a planetary atmosphere, a strong shock wave is formed around the space vehicle, resulting in the severe aerodynamic heating. To protect the space vehicle from the heat load, a thermal protection system (TPS) is required. Arcjet facilities have been widely used for the heat tests of TPS in entry flight conditions. The performance of TPS is evaluated and updated through the heat tests. However, characteristics of test flows in an arcjet facility are not understood well because it is out of thermochemical equilibrium, degrading the accuracy of the heat tests. Experimental and numerical studies have been conducted to characterize the freestream and shock layer flows in arcjet facilities~(1~3). These past studies are useful to understand the flow properties in an arcjet facility. However, the complete characterization of arcjet flows has not been yet possible. So, father studies of arcjet flows are required to characterize the test flows used for the heat tests of TPS in entry flight conditions. The present study investigates the shock layer flows generated in the arcjet facility at the Institute of Space and Astronautical and Science (ISAS) of Japan Aerospace Exploration Agency (JAXA)~(4)). Radiation from the shock layer flows around a blunt body is observed by emission spectroscopy and flow temperatures are evaluated by a spectrum fitting method.