Nucleation site density in pool boiling of binary mixtures: Effect of surface micro-roughness and surface and liquid physical properties

The nucleation site density (N/A) during pool boiling of binary mixtures has been experimentally examined in terms of the heating surface physical properties, the liquid physical properties, the vapour liquid equilibria and the surface micro-roughness, The liquid mixtures used were acetone-carbon tetrachloride and n-hexane-carbon tetrachloride, A parameter R-a,, to characterize the micro-roughness of the heating surface was defined as the average value of the peaks and valleys on the surface. The study shows that while at low R-a, values the physical properties of the liquid and the binary composition are not as important as the surface roughness; at higher R-a, values the liquid properties and composition are also important. A correlation based on the present data has been proposed.