Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/3206
Title: The effect of tube diameter on vertical two-phase flow regimes in small tubes
Authors: Chen, L
Tian, YS
Karayiannis, TG
Keywords: Boiling;Test facilities;Experimental study;Circular pipe;Capillary tube;Vertical pipe;Refrigerant fluid;Flow regime;Two-phase flow
Issue Date: 2006
Publisher: Elsevier
Citation: International Journal of Heat and Mass Transfer, 49(21-22): 4220-4230
Abstract: Flow boiling flow patterns in four circular tubes with internal diameters of 1.10, 2.01, 2.88 and 4.26 mm were investigated in the present project. The experiments were conducted in vertical upward two-phase flow using R134a as the working fluid. The observed flow patterns include dispersed bubble, bubbly, confined bubble, slug, churn, annular and mist flow. The flow characteristics in the 2.88 and 4.26 mm tubes are similar to those typically described in normal size tubes. The smaller diameter tubes, 1.10 and 2.01 mm, exhibit strong "small tube characteristics" as described in earlier studies. The sketched flow maps show that the transition boundaries of slug-churn and churn-annular depend strongly on diameter. On the contrary, the dispersed bubble to churn and bubbly to slug boundaries are less affected. The transition boundaries are compared with existing models for normal size tubes showing poor agreement.
URI: http://bura.brunel.ac.uk/handle/2438/3206
ISSN: 0017-9310
Appears in Collections:Mechanical and Aerospace Engineering
Dept of Mechanical Aerospace and Civil Engineering Research Papers

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