Development of Boiling Heat Transfer Analysis Method

In this study, a numerical analysis method applicable to estimation of the boiling heat transfer has been developed. Currently, the experimental correlations or the empirical laws have been applied to evaluate the boiling heat transfer. Therefore, it is difficult to predict the effects of the change of the heated surface geometry, thermal-hydraulic conditions, the surface activation or modification, because out of the application range of these correlations. The purpose of this work is to construct the boiling two-phase analysis method for thermo-fluid phenomena, and to realize “Design-by-Analysis” independent on the experiments and empirical laws. For this purpose, it is important to predict steam-water interface structure characteristics of the two-phase flow directly. Until now, for evaluating the boiling phenomena, Diffusive Interface Model for the bubble interface tracking was applied. In this model, the steam-water interface is diffuse with a finite width, and values of the thermodynamic properties change between water and steam smoothly within the interface region. For evaluating the wettability of heated surface, the surface energy is estimated by using the phase-field model. The wetting phenomena during boiling are able to be analyzed directly with this model. We present the numerical results of nucleate pool boiling phenomenon by using the developed analysis method. We succeeded in simulating the boiling process, vapor bubbles nucleation, growth, and departure behavior on a heated surface. By present analysis method, it was confirmed that the boiling heat transfer coefficient could be evaluated quantitatively without the experimental correlations.Copyright © 2014 by ASME