Visualization of foam formation from vertically free-falling impinging water jet

Abstract

The phenomenon of foam formation by air entrainment of impinging water jet is reported in this paper. An effort has been made to understand the physics of the phenomenon through visual and photographic observations. The formation of an air sheath and downward motion of the impinging jet are reported. Experimental visualization of the mechanism of air entrainment by foam formation at low jet flowrates of \(8.33 \times 10^{ - 6} - 1.83 \times 10^{ - 6} {\text{m}}^{3} /{\text{s}}\) for jet lengths of 13, 18, 23 and 25 cm, respectively, was performed with a vertically free-falling jet. Foam formation via air entrainment has been classified into four types: no entrainment, incipient entrainment, intermittent entrainment and continuous entrainment with increases in jet impinging velocity with fixed jet length. Foam formation depends on the impinging jet velocity, nozzle design, impinging jet length and physical property of the jet such as the surface tension which constitutes the major controlling factors for foam formation via air entrainment of impinging jet.

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References

  1. Ansari S, Nobes DS (2020) Interaction of loosely packed bubbly flow passing through a pore space. J Vis 23:649–660. https://doi.org/10.1007/s12650-020-00649-8

    Article  Google Scholar 

  2. Bertola N, Wang H, Chanson H (2018) A physical study of air–water flow in planar plunging water jet with large inflow distance. Int J Multiph Flow 100:155–171

    Article  Google Scholar 

  3. Biń AK (1993) Gas entrainment by plunging liquid jets. Chem Eng Sci 48(21):3585–3630. https://doi.org/10.1016/0009-2509(93)81019-R

    Article  Google Scholar 

  4. Chanson H (2009) Turbulent air–water flows in hydraulic structures: dynamic similarity and scale effects. Environ Fluid Mech 9(2):125–142

    MathSciNet  Article  Google Scholar 

  5. Chanson H, Aoki S, Hoque A (2004) Physical modelling and similitude of air bubble entrainment at vertical circular plunging jets. Chem Eng Sci 59(4):747–758

    Article  Google Scholar 

  6. Chanson H, Aoki S, Hoque A (2006) Bubble entrainment and dispersion in plunging jet flows: freshwater vs. seawater. J Coast Res 22:664–677

    Article  Google Scholar 

  7. Cummings PD, Chanson H (1999) An experimental study of individual air bubble entrainment at a planar plunging jet. Chem Eng Res Des 77(2):159–164

    Article  Google Scholar 

  8. Kiger KT, Duncan JH (2012) Air-entrainment mechanisms in plunging jets and breaking waves. Annu Rev Fluid Mech 44(1):563–596

    MathSciNet  Article  Google Scholar 

  9. Kim H, Park KS, Hwang DH (2014) Replacing open channel with pipe channel and flap gate to avoid foam formation at outfall of angamos power plant in Chile. VibroEngineering Procedia 4:1–5

    Google Scholar 

  10. Oh YM, Kang G-S, Kim JY, Oh SH (2008) Analysis of efficiency of reducing bubble generation in the drain waterway of power plant by using image processing technique. Korean Soc Civ Eng 2008(10):4268–4271

    Google Scholar 

  11. Oh YM, Oh S-H, Jang S-C (2010) Reduction of the foam generated in the discharge channel of a power plant. J Korean Soc Coast Ocean Eng 22(4):235–240

    Google Scholar 

  12. Qu X, Goharzadeh A, Khezzar L, Molki A (2013) Experimental characterization of air-entrainment in a plunging jet. Exp Therm Fluid Sci 44:51–61

    Article  Google Scholar 

  13. Roy AK, Maiti B, Das PK (2013) Visualisation of air entrainment by a plunging jet. Procedia Eng 56:468–473

    Article  Google Scholar 

Download references

Acknowledgements

This research was supported by GS ENC Co. This research was also supported by the National Research Foundation of Korea (NRF) Grant, which is funded by the Korean government (MSIT) (No. 2020R1A5A8018822, No. 2018R1A2B2007117).

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Correspondence to Kyung Chun Kim.

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Ekwonu, M.C., Kim, K.C. Visualization of foam formation from vertically free-falling impinging water jet. J Vis 24, 9–17 (2021). https://doi.org/10.1007/s12650-020-00693-4

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Keywords

  • Visualization
  • Foam formation
  • Vertical impinging jet
  • Air entrainment