Measurement and modeling of average void fraction, bubble size and interfacial area

Kocamustafaogullari, G.; Huang, W.D.; Razi, J.

doi:10.1016/0029-5493(94)90124-4

Cited by 117 publications

(25 citation statements)

References 15 publications

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“…In view of the great importance to two-fluid model, local measurement of these flow parameters such as void fraction and interfacial area concentration have been performed in a bubbly flow intensively over the past 10 years [1][2][3][4][5][6][7][8][9][10][11][12]. However, most of experiments were performed in round tubes.…”

Section: Introductionmentioning

confidence: 99%

Local flow measurements of vertical upward bubbly flow in an annulus

Hibiki

Situ

et al. 2003

International Journal of Heat and Mass Transfer

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Section: Introductionmentioning

confidence: 99%

Local flow measurements of vertical upward bubbly flow in an annulus

Hibiki

Situ

et al. 2003

International Journal of Heat and Mass Transfer

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“…In view of the small bubble sizes measured in the current study, together with the negligible expected relative velocity between the two phases, the effects on the bubble shape of the average pressure fluctuations generated by the turbulent liquid fluctuations, as defined by Kocamustafaogullari et al [9], are expected to be negligible. Table 1).…”

Section: Resultsmentioning

confidence: 61%

“…Similar conclusions were made by Thorncroft et al [8] in their studies in vertical up flow and down flow boiling. When discussing the bubble shape in horizontal bubbly flow, Kocamustafaogullari et al [9] reported that due to the negligible relative velocity between the two phases, the average pressure fluctuations generated by the turbulent liquid fluctuations acting across a bubble diameter are the only means which could cause a distortion to the bubble shape.…”

Section: Introductionmentioning

confidence: 99%

Bubble shape and breakage events in a vertical pipe at the boiler flow line

Fsadni

2014

EPJ Web of Conferences

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Abstract. The theoretical and experimental aspects concerning the typical bubble shape at the flow line of a standard domestic central heating system are investigated. This is done in support of the on-going research on two-phase flows in domestic central heating systems. Bubble nucleation and detachment at the primary heat exchanger wall of a domestic central heating boiler results in a bubbly two-phase flow in the system pipe work. Bubbly flow results in undesired cold spots at higher points in the system, consequently diminishing system performance. An experimental analysis was done on the bubble shape at the exit of the boiler through the application of photographic techniques. The results are presented in terms of the measured bubble aspect ratios at some principal system operating conditions. The dimensionless Eotvos and bubble Reynolds number were calculated and tabulated with the measured mean diameters. The data was subsequently correlated to the bubble shape regime diagram. Results suggest that most bubbles are quasi-spherical in shape with a noticeable elongation at lower bulk fluid Reynolds numbers.

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“…This observation indicates that the bubbles are accelerated by liquid inertia in a very short distance after mixing and closely follow the local liquid phase velocity, and that there is no evidence to suggest a strong proportionate correspondence between void fraction and velocity profiles, as suggested by Beanie (1972). Detailed experimental studies on the average velocity and drift velocity are given elsewhere (Kocamustafaogullari, 1994). The internal structure development fYom the first section to the third section and the gravitational segregation are more gradual in the high gas flows than in the low gas flows.…”

Section: A mentioning

confidence: 99%