Pressure and velocity measurements on detonation waves in hydrogen-oxygen mixtures

Abstract

Measurements are described of the static pressures and velocities of detonation waves in hydrogen-oxygen mixtures, together with the pressures arising on their normal reflexion at the closed end of the explosion tube. Two explosion tubes, of diameter 10 and 1·6 cm, were employed to study the diameter effect on the wave pressures. The experimental results are compared with calculated values of the wave properties for a range of hydrogen-oxygen mixtures initially at atmospheric pressure. In the 10 cm tube the static pressures and velocities are found to agree well with theory for mixtures with hydrogen content in the approximate range 50-75%; the evidence from pressure profiles and wave velocities indicates that mixtures outside this range may not be able to support ideal C–J waves. Detonation waves in all the mixtures studied in the 1·6 cm tube are found to be subideal. A possible explanation, in terms of energy loss to the tube wall, of the discrepancy between experiment and theory is discussed. Spinning occurs in mixtures near the limits of detonation in the smaller tube; the measured frequencies are found to be in reasonable agreement with the values predicted by the theories of Manson (1947) and Fay (1952).