Modelling and Identification of Pool Boiling Heat Transfer Phenomena
Fortschritt-Berichte VDI, Nr. 847, VDI-Verlag, Düsseldorf, 2005
A model-based experimental analysis to the identification of relevant pool boiling heat transfer mechanisms along the entire boiling curve is presented. It encompasses the model-based design of test heaters, the design, formulation and solution of inverse problems of the heated wall and the two-phase flow to identify boiling heat flux fluctuations at the boiling surface from heater-interior temperature measurements and to identify the interfacial geometry of the two-phase flow close the boiling surface. The present work shows that the dominant heat transfer mechanisms in boiling can be attributed to the interfacial evolution of the wetting structure at and very close to the boiling surface. Local peak heat fluxes of several MW/m2 exceed the average boiling heat flux by an order of magnitude. Optical probe data of the two-phase flow is successfully captured using a mathematical model for the interfacial geometry. The boiling heat flux in all boiling regimes is successfully correlated with interfacial area density in a unifying manner. The suggested correlation is superior compared to other correlations proposed in the literature if model discrimination techniques are applied.