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ISSN Online: 2377-424X

ISBN Print: 0-89116-299-2

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

MEASUREMENT OF TRANSIENT SURFACE TEMPERATURES BENEATH LEIDENFROST WATER DROPS

Get access (open in a dialog) DOI: 10.1615/IHTC7.3890
pages 131-136

Résumé

Transient surface temperature was measured as high speed motion pictures were taken of the impact of a 4.7 mm diameter water drop upon a quartz surface at a temperature above the Leidenfrost temperature. The thermometer used was a four lead, platinum film, resistance thermometer 0.25 × 1 mm in area. Initial surface temperatures of 300 to 500±C were studied. Pictures were taken at 600 to 1000 frames per second with a rotating drum camera. The temperature record displayed a pattern closely related to drop movement. Several times the temperature rapidly fell in less than a millisecond but then, almost as rapidly, rose back to a temperature somewhat below that of a couple of milliseconds earlier. A rapid temperature drop occurred immediately upon impact and again repeatedly as the drop gathered preparatory to rising off the surface. The surface temperature fell more during the latter period than earlier. Bulges that the drop formed as it was recollecting appeared coupled with the repeated drops in surface temperature.