Macrolayer Formation Model for Prediction of Critical Heat Flux in Saturated and Subcooled Pool Boiling.

A macrolayer formation model for predicting the critical heat flux (CHF) in saturated and subcooled pool boiling was proposed. The concept of this model was based on the bubble coalescence process, which was observed using a high-speed camera. In the present model, the thickness of the macrolayer was calculated assuming that the liquid volume remaining under the lower part of the bubble should contribute to the formation of the layer. A Poisson distribution was adopted for the distribution of nucleation sites. The predicted macrolayer thicknesses were used for the prediction of CHFs in saturated and subcooled pool boiling based on the macrolayer dryout model. This model reproduced the CHF values for pool boiling up to subcooling 40 K. The model concept was confirmed using a computational fluid dynamics code, where the assumption was that the liquid was captured and the macrolayer was formed at the coalescence of bubbles. [ABSTRACT FROM AUTHOR]