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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

EFFECT OF METAL THERMAL PROPERTIES ON BOILING CURVES OBTAINED BY THE QUENCHING METHOD

Get access (open in a dialog) DOI: 10.1615/IHTC7.3930
pages 155-160

Аннотация

Boiling curves, q vs. ΔT, can be obtained from quenching tests, provided it can be proved that a quasi-steady-state condition exists during the entire cool-down of the metal. This research examined the role of the thermal properties of the solid by using five pure metals: copper, aluminum, zinc, lead, and bismuth. The thermal conductivity at room temperature covered a range of about 50 to 1. Each test piece was a 5.08 cm. diameter circular slab, face-up, insulated at the sides and bottom. The thickness l varied from 0.1 to 20.3 cm. Liquid nitrogen at atmospheric pressure was boiled on the flat surface as the transient temperature vs. time data for the solid were fed directly to a computer. The inverse conduction solution of Kudryavtsev, modified for λ and Cp as functions of temperature, was used to produce the final boiling curves. It was found that one criterion for a quasi-steady-state for a flat plate is that the Biot number αl/λ be greater than 0.9 at all times. Specimens failing to meet this criterion gave maximum values which were too small, the worst case being too small by 77%.