Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

SIMULATION OF THE EFFECTS OF OIL ON HEAT TRANSFER DURING CONDENSATION OF REFRIGERANTS R-12 AND R-134a

Get access (open in a dialog) DOI: 10.1615/IHTC11.550
pages 421-426

Abstrakt

The presence of oil results in a reduction in the heat transfer coefficient for smooth tubes during condensation of refrigerants CFC-12 and HFC-134a. This reduction is approximately 15% for oil concentrations of 5% by weight. A mathematical model is developed, based in a local analysis, where the conservation equations are solved for small control volumes, following the flow of the refrigerant fluid along the condenser tube. Flows patterns of a refrigerant, with and without small amounts of oil, were investigated and simulated. To determine the variation in the thermodynamic properties of the condenser for oil-refrigerant mixtures, a theoretical approach based on Raoul's law for ideal solutions was adopted. In general, compared to the pure refrigerant case, the addition of oil dramatically deteriorates the local heat transfer performance for most of quality range.