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ISSN Online: 2377-424X

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

Simultaneous visualization of dry spots and bubbles for pool boiling of R-113 on a short horizontal heater

Get access (open in a dialog) DOI: 10.1615/IHTC12.4590
6 pages

摘要

A visualization study on the behavior of bubbles and dry spots has been carried out for pool boiling of R-113 on a horizontal heater. The behavior of bubbles and dry spots was recorded simultaneously, and the sectional views of the bubble structure were obtained separately. From video image analysis, the formation of bubbles and dry spots occurs simultaneously, and therefore they should be considered as a synchronized concept rather than independent identities. The dry spot density is equivalent to the active site density up to heat fluxes 50% of CHF. Before burnout liquid is intermittently supplied to the surface by two modes: during a formation cycle of small vapor film at the liquid-vapor interface and departure of a large vapor mass. Burnout comes from the local limited nucleate boiling activity at the wetting region rather than the hydrodynamic instabilities.