Jong Boong Lee

Various formulas and their accuracy concerning convective heat and mass transfer in the vapor boundary layer in the case of laminar film condensation of binary vapor mixtures

Abstract The equations of convective mass transfer are derived from the equations of convective heat transfer by replacing Nuc with Sh and Prv with Sc and also (χ+/ω)Gr with (χ/ω)Gr for free- condensation. As for forced-convection condensation, the equations of Rose and Fujii el al. and the newly presented equation for mass transfer have almost the same accuracy, although their functional forms are quite different from each other. The accuracy of Roses equation for heat transfer decreases as the effect of the enthalpy diffusion term increases. As for free-convection condensation, the newly presented equation for mass transfer is applicable in a wider range of WR or M in comparison with the previous equation of Fujii et al.

二成分混合蒸気の凝縮における気相境界層の代表物性値 : II 層流自由対流凝縮の場合

The numerical analysis is made for free-convection condensation of binary vapor mixtures quite similarly as the case of forced-convection condensation. The physical properties which are evaluated at the arithmetic mean of the mass concentrations at the vapor-liquid interface and the bulk and the corresponding saturation temperature are recommended as the representative ones in the case of the algebraic solution.

Laminar Forced-Convection Condensation of Saturated Vapors in the Subcritical Region.

A numerical analysis is presented for laminar forced-convection condensation of saturated vapors of water and carbon dioxide on a flat surface in the reduced temperature range TS/TC=0.990∼0.999. The heat transfer coefficient in the region TS/TC<0.998 can be correlated by using Fujii and Ueharas equation for constant physical properties when the representative physical properties are evaluated at the film temperature. The reduction of condensation mass flux or the heat flux at the vapor-liquid interface due to the convection term in the film is expressed as a function of the phase change number with the average isobaric specific heat.