Heat transfer in nucleate boiling of binary mixtures (Heat transfer measurement and assessment of available correlations)

Heat transfer coefficients in nucleate pool boiling of binary mixtures were measured on a circular copper plate, 40 mm in diameter, for a wide range of heat fluxes and concentrations. Measurements were done for five mixtures of methanol/water, ethanol/water, methanol/ethanol, ethanol/n-butanol, and methanol/benzene, each in the saturated boiling under atmospheric pressure. Measured data were expressed in the form a = Cq(n) for each concentration including pure components, where alpha is the heat transfer coefficient, q is the heat flux, and C and n are constants. The validity of available correlations for the boiling heat transfer of binary mixtures was assessed based on the measured data. Of the five correlations compared, the Stephan and Korner correlation is found the most appropriate although it needs an empirical constant that varies according to the mixture.