Measurement of radial gas phase temperature profiles in a 20-mm caliber gun

Absorption-emission spectroscopy is applied to the measurement of gas-phase, radial temperature distributions in the barrel of a 20 mm calibre, single stage, light gas gun. The gun fires mixtures of 02, H2, He or 02, H2, He, CO. Observations are made along three optical paths and they are analyzed using optical computer tomography. The gas-barrel interface temperature is measured with a fast response surface thermocouple. It is found that separation of the lighter and heavier gases occurs in both axial and radial directions. Gas temperature also varies in both axial and radial directions and the thermal boundary layer is much thinner than the velocity boundary layer.