EPJ Web of Conferences
Volume 45, 2013EFM12 – Experimental Fluid Mechanics 2012
|Number of page(s)||6|
|Published online||09 April 2013|
Two-phase distribution in the vertical flow line of a domestic wet central heating system
1 School of Built and Natural Environment, Room: Kirkham 124, University of Central Lancashire, Preston, PR1 2HE, UK
2 Department of Mechanical Engineering, Room: H118, Brunel University, Uxbridge, UB8 3PH, UK
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The theoretical and experimental aspects of bubble distribution in bubbly two-phase flow are reviewed in the context of the micro bubbles present in a domestic gas fired wet central heating system. The latter systems are mostly operated through the circulation of heated standard tap water through a closed loop circuit which often results in water supersaturated with dissolved air. This leads to micro bubble nucleation at the primary heat exchanger wall, followed by detachment along the flow. Consequently, a bubbly two-phase flow characterises the flow line of such systems. The two-phase distribution across the vertical and horizontal pipes was measured through a consideration of the volumetric void fraction, quantified through photographic techniques. The bubble distribution in the vertical pipe in down flow conditions was measured to be quasi homogenous across the pipe section with a negligible reduction in the void fraction at close proximity to the pipe wall. Such a reduction was more evident at lower bulk fluid velocities.
© Owned by the authors, published by EDP Sciences, 2013
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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