Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 0-89116-299-2

International Heat Transfer Conference 7
September, 6-10, 1982, Munich, Germany

INVESTIGATION OF SURFACE TENSION AND GRAVITY EFFECTS IN FILM CONDENSATION

Get access (open in a dialog) DOI: 10.1615/IHTC7.560
pages 175-180

Abstrakt

Horizontal integral-fin tubes are widely used for condensation of refrigerants and organic fluids. Beatty and Katz developed a gravity drained model to predict the condensation performance of such tubing. Our work evaluated a "spine-fin" condensing surface, for which the gravity drained model predicted a substantial improvement over conventional integral-fin tubing. The spine-fin surface geometry was machined on the surface of a 51 mm diameter block and tested with R-12. Surprisingly, its performance was 40% below the predicted value. A vertical, longitudinal-fin surface was tested and its performance was 300% higher than predicted by the gravity drained model. Due to these discrepancies, the scope of the work was redirected to explain the unexpected test results. An analytical model, based on surface tension drainage, was formulated and applied to the test data on the longitudinal finned surface. This model predicted the performance within 10%. We therefore conclude that a gravity drained model is not appropriate for enhanced surfaces of the integral or spine-fin varieties.