NUSSELT NUMBER FOR DIRECT-CONTACT EVAPORATION OF A MOVING ELLIPSOIDALDROP IN AN IMMISCIBLE LIQUID

Since Sideman et al.([1]) derived an analytical solution of the Nussel t number for a spherical drop in the direct contact evaporation in an immiscible liquid, many researchers have performed theoretical researc h on this field under different assumptions([2]-[6]). However drops mo ving in another immiscible liquid do not take a spherical form, but ob late form, which may be well approximated as an ellipsoid. This paper establishes the mathematical model of heat transfer for a moving ellip soidal drop in an immiscible liquid, and presents results from numeric al calculation. The relationship of the Nusselt number with the Weber number and the Peclet number is given, which is suitable for a relativ ely large range of We and Pe. The theoretical results for the Nusselt number show good agreement with experimental data. Some important conc lusions are obtained.