Heat Transfer in Nucleate Boiling of Binary Mixtures. (Development of a Heat Transfer Correlation).

Abstract

Heat transfer coefficients in nucleate pool boiling of five binary mixtures were measured under atmospheric pressure on an upward-facing heated surface for a wide range of heat flux from about 15 percent of the critical heat flux to close to it. Mixtures were : methanol / water, ethanol / water, methanol / ethanol, tehanol / n-butanol, and methanol / benzene. As has been observed in many previous experiments, heat transfer coefficients of mixtures were reduced in comparison with interpolated values between their constituent components. This reduction was a function of the mixture composition and became more pronounced with an increase in heat flux. To provide a simpler and more reliable prediction of heat transfer coefficients of mixtures, Thome correlation was modified so as to include the effect of heat flux in a dimensionless form. A newly developed correlation in this way was verified to predict heat transfer coefficients for the present five mixtures well within ±20 percent accuracy lines.