An Experimental Analysis of Water–Air Two-Phase Flow Pattern and Air Entrainment Rate in Self-Entrainment Venturi Nozzles
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Department of Mechanical Engineering, Graduate School, Seoul National University of Science and Technology, Seoul 01811, Korea
2
Department of Mechanical and Automotive Engineering, Seoul National University of Science and Technology, Seoul 01811, Korea
*
Author to whom correspondence should be addressed.
Academic Editor: Adrian Ilinca
Energies 2021, 14(9), 2664; https://doi.org/10.3390/en14092664
Received: 16 April 2021
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Revised: 2 May 2021
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Accepted: 3 May 2021
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Published: 6 May 2021
For self-entrainment venturi nozzles, the effects of nozzle shapes and operating conditions on the water–air two-phase flow pattern, and the characteristics of the air entrainment rate have been investigated. A rectangular venturi nozzle with width and height dimensions of 3 mm and 0.5 mm was used with a vertically downward flow direction. The pressure ratio, which is the ratio of the inlet and outlet pressures, water flow rate, and diverging angle were set as experimental parameters. From the flow visualization, annular and bubbly flows were observed. In the case of bubbly flow, the more bubbles that are generated with a higher water flow rate, the smaller the pressure ratio. In the case of annular flow, the increased pressure ratio and water flow rate induce the breakup of air core in the diverging area and make the interfacial oscillation stronger, which finally causes the flow transition from annular to bubbly flow, by accompanying a sharp increase in the air entrainment rate. During this flow transition, the frictional pressure drop of the two-phase flow is reduced, showing that a two-phase multiplier gets smaller.
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Keywords:
self-entrainment venturi nozzle; two-phase flow; pressure ratio; flow visualization; annular flow; bubbly flow; flow transition; two-phase multiplier
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MDPI and ACS Style
Bae, H.; Sung, J. An Experimental Analysis of Water–Air Two-Phase Flow Pattern and Air Entrainment Rate in Self-Entrainment Venturi Nozzles. Energies 2021, 14, 2664. https://doi.org/10.3390/en14092664
AMA Style
Bae H, Sung J. An Experimental Analysis of Water–Air Two-Phase Flow Pattern and Air Entrainment Rate in Self-Entrainment Venturi Nozzles. Energies. 2021; 14(9):2664. https://doi.org/10.3390/en14092664
Chicago/Turabian StyleBae, Hyunwoo, and Jaeyong Sung. 2021. "An Experimental Analysis of Water–Air Two-Phase Flow Pattern and Air Entrainment Rate in Self-Entrainment Venturi Nozzles" Energies 14, no. 9: 2664. https://doi.org/10.3390/en14092664
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