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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Influence of Gap Size on Boiling and Condensation Co-existing Phase Change Heat Transfer in Small Confined Space

Get access (open in a dialog) DOI: 10.1615/IHTC15.pbl.008805
pages 6419-6433

Resumo

This paper experimentally presents the influence of gap size on boiling and condensation co-existing phase change heat transfer characteristics in small confined space. The confined space gap is a closed phase change chamber that consists of a heating copper block whose top is an extension surface and used for boiling, a cooling copper block whose bottom surface is used for condensing and a transparent glass wall made of quartz for observation. The working media is de-ionized water. The heating and cooling surfaces are polished copper. Three different heights of the phase change chambers that represent three different gap sizes were experimentally studied. The first one is 48 mm in height with the water layer thickness in it is set at 10 to 34 mm; The second one is 33 mm in height with the water layer thickness in it is set at 9 to 21 mm; The third one is 18 mm in height with the water layer thickness in it is set at 6 to 12 mm. Experimental observation and results show that boiling and condensation processes are strongly inter-related and have significant influences over each other and the disturbance of the water has a great influence on heat transfer. As the water level increases, for the three different gap sizes of the confined space, both the boiling and condensation heat transfer coefficient increases at first and then decreases and there always exists an optimum water filling amount at which both the boiling and the condensation heat transfer coefficient acquire their maximum value.