Fundamental studies of cavity-based flameholder concepts for supersonic combustors

Experimental and computational investigations of the flowfield associated w ith several cavity-based flameholders in a nonreacting supersonic how are d escribed. All cavity flows were of the open type, that is, length-to-depth ratio L/D < 10, Two values of LID were studied with several offset ratios ( OR) and aft ramp angles <theta>, Results indicate that the aft ramp angle p lays an important role in determining the character of the shear layer that spans the cavity. For a rectangular cavity with OR = 1 and theta = 90 deg, a compression wave forms as the how separates from the cavity's upstream c orner, A strong recompression occurs at the aft wall, and the how is visibl y unsteady. The pressure on the cavity fore wall decreases steadily and the recompression process occurs more gradually with decreasing aft ramp angle , Higher drag coefficients and shorter residence times are found in cavitie s with shallower ramp angles.