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ISSN Online: 2377-424X

ISBN CD: 1-56700-226-9

ISBN Online: 1-56700-225-0

International Heat Transfer Conference 13
August, 13-18, 2006, Sydney, Australia

TWO-PHASE PRESSURE DROP AND VOID FRACTION DURING FLOW BOILING OF A HYDROCARBON FLUID

Get access (open in a dialog) DOI: 10.1615/IHTC13.p28.230
10 pages

摘要

The paper reports pressure drop data for iso-octane boiling in vertical upflow in a 8 m long, 25.4 mm i.d. tube, heated by direct electrical heating. The trends of the measured pressure gradient are checked with respect to vapour quality, mass flux and pressure. After confirming that these trends are systematic, the two-phase pressure drop data are examined in terms of their constituent parts, namely, acceleration, friction and gravity components. Subsequently, the data dominated by gravity component are used to back calculate void fractions and these are compared with various correlations including the HTFS void fraction method. Some correlations performed better than others in predicting the void fraction data. However, it is observed that generally the measured void fraction is lower than expected in the high vapour quality region, even when the quality approaches near dryout value. In order to explain this behaviour, a simple model is proposed to calculate void fraction as a function of local vapour quality in the post dryout region.