Velocity, pressure and temperature measurement in low-pressure supersonic flow

In order to determine the thermodynamic conditions in supersonic flow, we measured the flow velocity, Mach number, density and temperature, as well as the pressure of unsteady flow in a submillisecond interval. In the cold model the time-dependent gas temperature could be measured at low temperatures in the supercooled condition below 100 K and at low pressures below 1000 Pa using the laser light absorption technique. The measured gas temperature was about 50–70 K, which coincided with the designed temperature range. In the hot model we observed the combustion of liquid spray in the supersonic flow.