Development of the detonation-driven expansion tube for orbital speed experiments

Abstract

The hypersonic flow at orbital speeds is a fundamental issue for the ground tests of aerospace crafts. The detonation-driven high-enthalpy expansion tube (JF16 expansion tube) was developed to investigate re-entry physics. A forward detonation cavity (FDC) driver was applied in the JF16 expansion tube to create stable driving flows. The sound speed ratio of the detonated to test gas was examined to minimize the magnitude of test flow perturbations. The acceleration section length, incident shock decay and diaphragms thickness were investigated in detail to obtain optimal operation parameters. Flow visualization was also carried out with schlieren system to demonstrate the test flow stability and the effective test duration. Experimental data showed that the test flow with a velocity of 8.3 km/s and a total enthalpy up to 40 MJ/kg can be generated successfully and the test duration lasts for more than 50 μs.