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 mixtur es has been experimentally examined in terms of the heating surface ph ysical properties, the liquid physical properties, the vapour liquid e quilibria and the surface micro-roughness, The liquid mixtures used we re acetone-carbon tetrachloride and n-hexane-carbon tetrachloride, A p arameter R-a,, to characterize the micro-roughness of the heating surf ace was defined as the average value of the peaks and valleys on the s urface. The study shows that while at low R-a, values the physical pro perties 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.