Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

H. O. S Castro
University of Rio Verde, Rio Verde-GO, Brazil

J. L. Gasche
State University of São Paulo - UNESP, Ilha Solteira-SP, Brazil

This work presents an experimental investigation of the ester oil ISO VG10-refrigerant R134a mixture flow with foam formation through a straight horizontal 3.22 mm diameter, 6.0 m long tube. An experimental apparatus was designed to allow the measurement of both pressure and temperature profiles along the tube as well as the visualization of the flow patterns. Tests were performed at different mass flow rates, several refrigerant mass fractions at the inlet of the flow, and inlet mixture temperatures around 30 °C. A liquid mixture flow with constant temperature and pressure gradient could be seen at the inlet of the tube. As the flow proceeded towards the exit of the tube the pressure drop produced a reduction of the refrigerant solubility in the oil yielding to the formation of the first bubbles. Initially, small and few bubbles could be noticed and the flow behaved as an intermittent bubbly flow. Then, the bubble population increased and intermittent foam flow was observed at the exit of the flow. Due to the large formation of vapor, both the temperature and pressure gradient of the mixture were largely reduced in this region of the flow.

MPH-03 pages DOI: 10.1615/IHTC13.p12.30 Download article

Article price - $35.00

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