HEAT-TRANSFER IN NUCLEATE BOILING OF BINARY-MIXTURES - (DEVELOPMENT OF A HEAT-TRANSFER CORRELATION)

Heat transfer coefficients in nucleate pool boiling of five binary mix tures were measured under atmospheric pressure on an upward-facing hea ted surface for a wide range of heal flux from about 15 percent of the critical heat flux to close to it. Mixtures were : methanol/water, et hanol/water, methanol/ethanol, ethanol/n-butanol, and methanol/benzene . As has been observed in many previous experiments, heat transfer coe fficients of mixtures were reduced in comparison with interpolated val ues between their constituent components. This reduction was a functio n of the mixture composition and became more pronounced with an increa se 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 n ewly developed correlation in this way was verified to predict heat tr ansfer coefficients for the present five mixtures well within +/-20 pe rcent accuracy lines.