INCAS Bulletin (Sep 2023)

Experimental investigation of the critical Reynolds number for bubbly two-phase flow

  • Marshall C. MCCRAY,
  • Paul G. A. CIZMAS

DOI
https://doi.org/10.13111/2066-8201.2023.15.3.4
Journal volume & issue
Vol. 15, no. 3
pp. 47 – 55

Abstract

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The critical Reynolds number for dispersed bubbly two-phase flows, gas in liquid, was experimentally investigated. In this experiment, the gas was air and the liquid was water. Water flowed upward through a vertical, translucent pipe, and air was introduced into the water prior to the test section by means of a basswood microbubbler. Dye was injected into the water to indicate when the flow transitioned from laminar to turbulent. Mixtures with gas volume fractions up to 10% were tested, and the Reynolds numbers for which the flow transitioned from laminar to turbulent were recorded. The data showed that the critical Reynolds number fell to roughly one-half of its original single-phase liquid value once the gas volume fractions exceeded 0.1%. These results indicate that the presence of even small amounts of bubbles causes pre-mature transition to turbulence.

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