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Record Details

Record 21 of 22881
Bubbly flow model for the dynamic characteristics of cavitating pumps
Author and Affiliation:
Brennen, C.(California Institute of Technology, Pasadena, Calif., United States)
Abstract: The recent experimental transfer matrices obtained by Ng and Brennen (1978) for some axial flow pumps revealed some dynamic characteristics which were unaccounted for by any existing theoretical analysis; their visual observations suggested that the bubbly cavitating flow in the blade passages could be responsible for these effects. A theoretical model of the dynamic response of this bubbly blade-passage flow is described in the present paper. Void-fraction fluctuations in this flow result not only from pressure fluctuations but also because the fluctuating angle of attack causes fluctuations in the rate of production of bubbles near the leading edge. The latter causes kinematic waves which interact through the boundary conditions with the dynamic waves caused by pressure fluctuation. The resulting theoretical transfer functions which results are in good qualitative agreement with the experiments; with appropriate choices of two parameters good quantitative agreement is also obtained. The theoretical model also provides one possible explanation of the observation that the pump changes from an essentially passive dynamic element in the absence of cavitation to a progressively more active element as the extent of cavitation increases.
Publication Date: Nov 28, 1978
Document ID:
19790034835
(Acquired Dec 01, 1995)
Accession Number: 79A18848
Subject Category: FLUID MECHANICS AND HEAT TRANSFER
Document Type: Journal Article
Publication Information: Journal of Fluid Mechanics; 89; Nov. 28
Publisher Information: United Kingdom
Contract/Grant/Task Num: NAS8-28046; NSF ENG-76-11225
Financial Sponsor: NASA; United States
Organization Source: California Inst. of Tech.; Pasadena, CA, United States
Description: 19p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: AXIAL FLOW PUMPS; CAVITATION FLOW; DYNAMIC CHARACTERISTICS; HYDRAULIC EQUIPMENT; MATHEMATICAL MODELS; TWO PHASE FLOW; ANGLE OF ATTACK; BOUNDARY CONDITIONS; BOUNDARY VALUE PROBLEMS; BUBBLES; ROTOR BLADES; TRANSFER FUNCTIONS
Imprint And Other Notes: Journal of Fluid Mechanics, vol. 89, Nov. 28, 1978, p. 223-240.
Miscellaneous Notes: 1978, p. 223-240
Availability Source: Other Sources
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