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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

FLOW PATTERN IDENTIFICATION WITH BOTH WALL TEMPERATURE DISTRIBUTIONS AND HEAT TRANSFER CHARACTERISTICS DURING REFRIGERANT EVAPORATION IN SPIRALLY GROOVED TUBE

Get access (open in a dialog) DOI: 10.1615/IHTC13.p12.320
13 pages

Аннотация

Experiments were carried out on the flow boiling of refrigerants inside a horizontal, spirally grooved steel tube with the 12mm average inner diameter. The circumferential temperature distributions of the tube surface and the axially local heat transfer coefficients of evaporating fluid inside the tube were measured using two fluorocarbons, HCFC22 and HCFC123. Experimental conditions were 100 to 300 kg/(m2s) in mass velocity, 0.2 to 0.3 MPa for HCFC123 and 0.8 to 1.1 MPa for HCFC22 in pressure, and nearly 0 to 25 kW/m2 in heat flux.
Based on both the measured circumferential temperature distributions and trends of average heat transfer coefficients, the liquid film thickness on the tube surface was estimated and discussed. The estimated flow conditions of the experimental data were classified into the following four flow patterns, separated flow with liquid meniscus, separated flow with dry surface, annular flow, and annular flow with liquid meniscus. All experimental data were sorted into four categories of flow patterns, and the flow pattern maps were presented in the form of mass velocity versus vapor quality using the sorted dataset.