The Effects of a Ribbed Wall on the Efficiency of a Wide Angle Subsonic Diffuser.

摘要

Tests were conducted to determine the effects of a ribbed wall on the efficiency of a single side expanded, wide angle, subsonic diffuser. Rib geometry, diffuser angle, Reynolds number, and Mach number were varied. Except at low Reynolds numbers, ribs were found to improve the efficiency of the diffuser. They were also more effective than vortex generators except at low Reynolds numbers for all Mach numbers and at high Mach numbers for all Reynolds numbers. The ribs produced maximum improvement at diffuser angles of 20 to 22 deg. The data indicated that the depth-to-width ratio of the grooves between the ribs should be in the range of 2 to 6. The range of Reynolds numbers and Mach numbers over which the ribs were effective appeared to be primarily a function of the groove width. (Author)