REGIME OF FROZEN BOUNDARY LAYERS IN STAGNATION REGION OF BLUNT REENTRY BODIES

The ratio of Damkohler number (average time a particle remains in the boundary layer to time required for atoms to recombine) to recombination rate constant was calculated assuming thermodynamic equilibrium exists outside the boundary layer. The results are presented for four altitudes between 150,000 and 300,000 ft, nose radii ranging from 1/2 to 10 ft, wall temperatures from 300 to 2000 K, ree-stream velocities ranging from 12,000 to 26,000 fps, and values of the wall catalytic reaction rate constant of 0 and 300 cm/sec. Assuming a recombination rate constant of 10 to the 16th power cm to the 6th power squared (sec) and that frozen flow exists when the Damkohler number is less than 10 to the -2nd power, frozen flow exists for a nose radius of 1 ft and a wall temperature of 1000 K above altitudes of 200,000 ft and 260,000 ft for velocities of 12,000 and 26,000 fps, respectively. The ratio of the heat transferred to a noncatalytic wall surface to the heat transferred to a perfect catalytic wall surface with a wall temperature of 1000 K at an altitude of 246,060 ft was approximately 0.5 and 0.22 for velocities of 12,000 and 26,000 fps, respectively. (Author)