HEAT-TRANSFER IN NUCLEATE POOL BOILING OF BINARY-MIXTURES

Heat transfer coefficients for nucleate pool boiling of binary mixtures were measured on a circular copper plate facing upwards. Tested mixtures were methanol/water, ethanol/water, methanol/ethanol, ethanol/n-butanol, and methanol/benzene, each in the saturated state at atmospheric pressure. Special stress was laid on elucidating the dependence of heat transfer reduction on mixture composition, physical properties, phase equilibrium diagram, and heat flux. Experimental data were compared with available correlating methods developed for binary mixtures by Stephan and Korner, and by others. The comparison showed that among the compared correlations, Stephan and Korner's correlation and Thome's correlation give fairly good results while their accuracy varies considerably with mixtures and heat flux levels. A modification of Thome's correlation so as to include the effect of heat flux succeeded in correlating the present data within +/- 20% accuracy.