Experimental study on subcooled nucleate boiling from a single artificial cavity

Abstract

Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.Bubbles condensing in subcooled water were experimentally studied in the aim of characterizing the nucleation behavior dependence on the water pool subcooled temperature. A single artificial cavity was created on a brass plate and heated by a laser beam in a water pool and high speed camera was used to capture bubble growth dynamics. Postprocessing allows the measurement of important parameters such as bubble volume, rising velocity, departure diameter, detachment frequency, volume variation versus time and temperature and dry spot diameter. Three growth regimes were identified according to the bulk temperature and the heat flux supplied: an equilibrium regime, a standard nucleate boiling regime and a boiling crisis regime in which we observed the formation of a large dry spot on the solid surface. The absence of rewetting of the cavity is a key feature of this regime. The obtained results are compared with the few experimental correlations available in the literature.