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ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

HEAT TRANSFER REGIMES IN FORCED-CONVECTION FILM BOILING ON SPHERES

Get access (open in a dialog) DOI: 10.1615/IHTC8.700
pages 2149-2154

要約

Heat transfer rates have been measured for nickel-plated copper spheres at temperatures ≤ 540 °C, moving downwards at velocities ≤ 1.8 ms−1 and in natural convection in water at 607−100 °C. Stable film boiling occurs at high wall temperatures in saturated or slightly subcooled water; the low rate of heat transfer is independent of velocity until the separation point of the vapour wake reaches the mid-point of the sphere. In water subcooled by more than 20K and at wall temperatures of 430−540 °C heat is transferred at a high rate in the microbubble regime. With decreasing wall temperature, these regimes transform to disturbed film boiling with a jump in heat flux (upwards from stable film boiling, downwards from microbubble boiling).