Abonnement à la biblothèque: Guest

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

ROUGHNESS EFFECTS ON NUCLEATE BOILING HEAT TRANSFER FROM CYLINDRICAL SURFACES TO REFRIGERANT R-134a

Get access (open in a dialog) DOI: 10.1615/IHTC13.p28.180
10 pages

Résumé

The present paper presents results of an experimental investigation carried out to determine the effects of the surface roughness of different materials on nucleate boiling heat transfer of refrigerant R-134a. Experiments have been performed over cylindrical surfaces of copper, brass and stainless steel. The surface has been treated by different methods in order to obtain an average roughness, Ra, varying from 0.03 μm to 3.5 μm. Boiling curves at different reduced pressures have been measured as part of the investigation. The obtained results have shown significant effects of the surface material, with brass being the best performing one and stainless steel the worst. It has also been determined that the surface treatment procedure exerts a significant effect over nucleate boiling heat transfer. In addition, the roughness effect presents a peculiar behavior characterized by a reduced rate of heat transfer increment with roughness up to a limit for which the thermal performance reaches a maximum.