Experimental study of air radiation behind a strong shock wave

This paper presents a description of the modernized detonation driven shock tube DDST-M, in which conditions that simulate the entry of spacecraft into the Earth's atmosphere at the super orbital velocity (11.2 km/s) are achieved. The modernization consists in the inclusion of an additional element in the shock tube design - the prechamber, which separates the end wall of the tube with the igniter from the main volume by the perforated disc. The presence of the prechamber increases the energy efficiency of the facility, primarily due to a more complete combustion of the combustible mixture in the high-pressure chamber, which makes it possible to obtain higher shock wave velocities in the low-pressure chamber. A series of experiments was carried out to study the radiation characteristics of high temperature air in the range of shock wave velocities VSW = 4.2 ÷ 11.4 km/s and initial gas pressures p0 = 0.25 ÷ 10 Torr. Analysis of the obtained data made it possible to distinguish the features of the radiation in different parts of the spectrum depending on the shock wave velocity and the initial gas pressure. The measurement results are compared with the results of other studies.