On the Mechanism of Forced-Convection Subcooled Nucleate Boiling

In highly subcooled nucleate boiling the bubbles grow and collapse while sliding along the heated surface, so that there is no net vapor transport away from the surface. A long-standing question exists as to whether conduction and convection between the bubbles, or latent heat transport through the bubbles, is the dominant heat transfer mechanism. It is shown here by simple calculations that the sliding of the bubble results in augmentation of microlayer evaporation under the bubble by a factor of two or more over a stationary bubble with a continuous microlayer. It appears therefore that the latent heat transport mechanism may be dominant at large bulk subcoolings.