NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
weak rotating flow disturbances in a centrifugal compressor with a vaneless diffuserA theory is presented to predict the occurrence of weak rotating waves in a centrifugal compression system with a vaneless diffuser. As in a previous study of axial systems, an undisturbed performance characteristic is assumed known. Following an inviscid analysis of the diffuser flow, conditions for a neutral rotating disturbance are found. The solution is shown to have two branches; one with fast rotation, the other with very slow rotation. The slow branch includes a dense set of resonant solutions. The resonance is a feature of the diffuser flow, and therefore such disturbances must be expected at the various resonant flow coefficients regardless of the compressor characteristic. Slow solutions seem limited to flow coefficients less than about 0.3, where third and fourth harmonics appear. Fast waves seem limited to a first harmonic. These fast and slow waves are described, and effects of diffuser-wall convergence, backward blade angles, and partial recovery of exit velocity head are assessed.
Document ID
19880066978
Document Type
Conference Paper
Authors
Moore, F. K.
(Cornell University Ithaca, NY, United States)
Date Acquired
August 13, 2013
Publication Date
June 1, 1988
Subject Category
FLUID MECHANICS AND HEAT TRANSFER
Report/Patent Number
ASME PAPER 88-GT-76
Distribution Limits
Public
Copyright
Other