Space Shuttle solid rocket motor aft-end internal flows

Abstract

Flow-visualization techniques were employed in a Vs-scale model of the Space Shuttle solid rocket motor to investigate the dominant aft-end internal flow patterns. The model included the two aft segments, the aft dome, and the convergent portion of the gimballed nozzle. The effects of blowing, which would result from gases produced by the burning propellant, were simulated through the introduction of a uniform distribution of water along simulated burn-back patterns representing the surface at three different times in a firing. It was found that the effects of vortices, shed from protruding inhibitor sections, upon flow a few diameters downstream were greatly diminished by the effects of wall injection. It was also found that the extent of circumferential flow resulting from the removal of a portion of protruding inhibitor was limited to the region near the missing portion. Strong circumferential flow in the aft dome was observed when no grain surface was present in the dome. This flow included nozzle-entrance vortices, which appear to result from interactions between the circumferential and toroidal flows associated with the submerged nozzle and the aft dome.