ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
Condensation of nitrogen in a hypersonic flow field produced by a small, 14.5-deg half-angle conical nozzle exhausting into vacuum has been studied using Rayleigh scattered radiation. Concomital measurements for the plume far-field gas density and rotational temperature were obtained using the electron beam fluorescence methods. Near-field plume gas density measurements were made with Raman scattering. The data taken were spatially resolved and had an axial extent of 14 or xD or 220. Radial scans were made at selected axial locations. The onset of condensation was observed, both as a function of reservoir pressure and as a function of axial location for selected reservoir pressures. The density data show that the condensation process does not markedly affect the plume density, except at the highest reservoir pressure. However, there is a significant effect on the rotational temperature, with the rotational temperature increasing with mass fraction condensed. Data obtained from the uncondensed portions of the plume were in good agreement with isentropic method of characteristics calculations. An approach for calculation of condensation effects is developed, and resulting calculations are in order of magnitude agreement with the experimental measurements.
Final rept. 1 Jul 1972-28 Feb 1973
Prepared in cooperation with ARO, Inc., Tullahoma, Tenn., Rept. no. ARO-VKF-TR-73-161.