Developing structure of two-phase flow in a large diameter pipe at low liquid flow rate

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)70-84
Journal / PublicationInternational Journal of Heat and Fluid Flow
Volume34
Publication statusPublished - Apr 2012
Externally publishedYes

Abstract

In order to develop the interfacial area transport equation for the interfacial transfer terms in the two-fluid model, accurate data sets on axial development of local parameters such as void fraction, interfacial area concentration, interfacial gas velocity and Sauter mean diameter are indispensable to verify the modeled source and sink terms in the interfacial area transport equation. From this point of view, local measurements of both group 1 spherical/distorted bubbles and group 2 cap/slug bubbles in vertical upward air-water two-phase flow in a large diameter pipe with 200. mm in inner diameter and 26. m in height were performed at three axial locations of z/. D= 41.5, 82.8 and 113 as well as 11 radial locations from r/. R= 0-0.95 by using four-sensor probe method. Here, z, r, D and R are the axial distance from the inlet, radial distance from the pipe center, pipe diameter and pipe radius, respectively. The liquid flow rate and the void fraction ranged from 0.0505. m/s to 0.312. m/s and from 1.98% to 32.6%, respectively in the present experiment. The flow condition covered extensive region of bubbly flow, cap turbulent flow as well as their transition. The extensive analysis on the radial profiles of local flow parameters and their axial developments demonstrate the development of interfacial structures along the flow direction due to the bubble coalescence and breakup and the gas expansion. The significant decrease in void faction and interfacial area concentration and the increase in Sauter mean diameter and interfacial velocity were observed when the gradual flow regime transition occurred. Finally, the net change in the interfacial area concentration due to the bubble coalescence and breakup was quantitatively investigated in the present paper to reflect the true transfer mechanisms in observed two-phase flows. © 2012 Elsevier Inc.

Research Area(s)

  • Four-sensor probe, Interfacial area concentration, Interfacial area transport, Large diameter pipe, Void fraction

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