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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Pool Boiling Heat Transfer from Tubes with and without Basic Surface Modification for Enhancement

Get access (open in a dialog) DOI: 10.1615/IHTC12.2330
6 pages

Аннотация

Pool boiling heat transfer from single, horizontal tubes with 25.4m m O.D. to 2-Propanol and refrigerant R134a (CH2F.CF3) is investigated to increase the knowledge about the fundamental processes promoting heat transfer enhancement in nucleate pool boiling. Surface modifications with comparatively simple geometries are applied to plain tubes with uniform surface roughness, and heat transfer is measured over wide ranges of heat flux and saturation pressure.
The results of local heat transfer at different circumferential positions of the tube wall are compared with corresponding data from measurements without surface modifications which have shown that the local superheat of the tube wall can be measured very accurately along the whole circumference of the tube (Gorenflo et al., 2000). The comparison reveals the influence of the surface modifications on the variation of local convective and evaporative effects as functions of heat flux, pressure, and circumferential position. Finally, the local heat transfer data are dicussed in connection with accurate measurements of the micro and macro topography of the tube surface.