Effect of Throat Surface Roughness on Jet Pump Performance

The jet pump generally needs a long throat to mix the driving and induced fluids and transfer the momentum of driving fluid to induced fluid. Simultaneously, the energy loses when the fluids flow through the long throat because the friction loss occurs inside of the throat wall. Therefore, it is kno...

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Bibliographic Details
Published inNihon Kikai Gakkai rombunshuu. B hen Vol. 72; no. 720; pp. 1895 - 1900
Main Authors YAMAZAKI, Yukitaka, NAKAYAMA, Tomonori, NARABAYASHI, Tadashi, KOBAYASHI, Hidetoshi, SHAKOUCHI, Toshihiko
Format Journal Article
LanguageJapanese
English
Published The Japan Society of Mechanical Engineers 2006
Subjects
Efficiency
Flow Resistance
Jet Pump
Surface Roughness
Throat
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Summary:The jet pump generally needs a long throat to mix the driving and induced fluids and transfer the momentum of driving fluid to induced fluid. Simultaneously, the energy loses when the fluids flow through the long throat because the friction loss occurs inside of the throat wall. Therefore, it is known that the throat length largely affects the jet pump efficiency. In this study, to obtain fundamental knowledge of the effect of surface roughness in the throat on jet pump performance, experimental studies were performed for a typical single nozzle jet pump using water at room temperature. It was revealed that surface roughness located nearer the throat inlet had a greatest effect on the jet pump efficiency because the local skin friction coefficient nearest the throat inlet is the largest. The best efficiency and its flow rate ratio decrease linearly as surface roughness increases. The frictional resistance coefficient in the throat for each roughness is made clear by fitting a one-dimensional theoretical prediction equation to the experimental results.
ISSN:0387-5016
1884-8346
DOI:10.1299/kikaib.72.1895