THE MEASUREMENT OF THE RATE OF DISSOCIATION OF OXYGEN AT HIGH TEMPERATURES

A new technique is described with which reaction rates in gases can be determined at high temperatures. First, the hydrodynamics of a dissociating diatomic gas is discussed the conservation equations are applied across a normal shock wave. The thermodynamic variables are calculated as a function of the degree of dissociation. A mech-ANISM OF THE SHOCK LOCATION IN FRONT OF A SPHERE TRAVELING AT SUPERSONIC SPEEDS IS PROPOSED. Then, the relation between the shock separation distance and the rate of dissociation is discussed. The method is applied to the dissociation of diatomic oxygen. The experiment was carried out in a ballistics range. Small spheres were fired into pure oxygen at velocities from 6,000 to 12,500 fps at pressures of 20, 100, and 200 mm mercury. The separation distance of the shock wave from the sphere is measured on photographs of the sphere in flight. The dissociation rate is given which provides the best fit of predicted detachment distance to the experimentally observed distance. Author