Accession Number:

ADA273744

Title:

Off-Design Performance of Crenulated Blades in a Linear Compressor Cascade

Descriptive Note:

Final master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING

Personal Author(s):

Report Date:

1993-12-01

Pagination or Media Count:

133.0

Abstract:

The effects of using compressor blades with a crenulated notched trailing edge in a low aspect ratio AR 1 linear compressor cascade at four incidence angles-1.08 deg, 4.49 deg, 9.32 deg and 12.44 deg were investigated. Blade performance and wake mixing characteristics for crenulated blades were compared with similar data for blades with a straight trailing edge. A seven-bladed cascade was operated with a flow Mach number of 0.4 and a blade chord Reynolds number of 4.1 105. The diffusion factor ranged from 0.22 to 0. 42 and strong three-dimensional flow effects were present. Total pressure losses were measured with a total pressure rake. Velocities and flow angles were measured using hot-film anemometry. Crenulated blades were found to enhance wake mixing from 20 to 50 percent depending on blade loading and downstream location. Crenulated blades were also found to reduce flow deflection by 1.9 deg at the lowest incidence and by 3.7 deg at the highest incidence. At the highest blade loading, crenulations were found to reduce total pressure losses by 20 percent and inhibit large scale flow degradation and vortex breakdown. At mild blade loadings, negligible differences in losses were observed.

Subject Categories:

  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE