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Effect of area ratio on the performance of a 5.5:1 pressure ratio centrifugal impellerA centrifugal impeller which was initially designed for a pressure ratio of approximately 5.5 and a mass flow rate of 0.959 kg/sec was tested with a vaneless diffuser for a range of design point impeller area ratios from 2.322 to 2.945. The impeller area ratio was changed by successively cutting back the impeller exit axial width from an initial value of 7.57 mm to a final value of 5.97 mm. In all, four separate area ratios were tested. For each area ratio a series of impeller exit axial clearances was also tested. Test results are based on impeller exit surveys of total pressure, total temperature, and flow angle at a radius 1.115 times the impeller exit radius. Results of the tests at design speed, peak efficiency, and an exit tip clearance of 8 percent of exit blade height show that the impeller equivalent pressure recovery coefficient peaked at a design point area ratio of approximately 2.748 while the impeller aerodynamic efficiency peaked at a lower value of area ratio of approximately 2.55. The variation of impeller efficiency with clearance showed expected trends with a loss of approximately 0.4 points in impeller efficiency for each percent increase in exit axial tip clearance for all impellers tested.
Document ID
19860063577
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Schumann, L. F.
(Army Propulsion Lab. Cleveland, OH, United States)
Clark, D. A.
(NASA Lewis Research Center and U.S. Army Propulsion Directorate Cleveland, OH, United States)
Wood, J. R.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
August 12, 2013
Publication Date
June 1, 1986
Subject Category
Aerodynamics
Report/Patent Number
ASME PAPER 86-GT-303
Accession Number
86A48315
Distribution Limits
Public
Copyright
Other

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