Method of Designing Vaneless Diffusers and Experimental Investigation of Certain Undetermined Parameters
Abstract
A method of designing vaneless diffusers, using data given for simple conical diffusers, is presented. The rate of expansion of the flow area through the diffuser is found in terms of an equivalent cone laid off along the logarithmic spiral having an angle equal to that for the optimum flow condition of the impeller. A family of diffusers with equivalent cone angles of 4, 6, and 8 deg, all having the same throat height, was designed and experimentally studied. A second series of the height just beyond the impeller outlet, and all having the cone angle corresponding to the best performance in the first tests (6 deg), was then constructed. A diffuser with the 6 deg equivalent cone angle and a contraction ratio of 0.72 was found to have the highest efficiency, about 0.83 at the diffuser exit at tip speeds of 900 to 1200 feet per second. The improved performance with the forementioned design parameters was particularly noticeable at high loads and tip speeds.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1947
- Accession Number
- ADA801392
Entities
People
- Guy R. Bradshaw
- W. B. Brown
Organizations
- Glenn Research Center