EXPERIMENTAL DETERMINATION OF TEMPERATURE AND PRESSURE GRADIENTS IN ROCKET EXHAUSTS.

Supported by NASA, George C. Marshall Space Flight Center, Huntsville, Alabama.Author Institution: Rocketdyne, A Division of North American Aviation, Inc.Exhaust plume temperature and pressure gradients are being determined in the nozzle exit region of a 1000 pound thrust rocket motor. The motor is fired into a supersonic diffuser to achieve altitude simulation and to assist in providing an optical path with a minimum of atmospheric absorption. Measurements of apparent plume radiance and emissivity are made at discrete wavelengths along lines of sight parallel to the nozzle exit plane during each motor firing. By making use of the Abel transformation, the line of sight measurements are converted into radial distributions of radiance and emissivity, from which the radial distribution of temperature for a particular species allows calculation of pressure or concentration distributions. Results are given for some recent motor firings of the propellant liquid oxygen-kerosene