COMPARISON OF VARIOUS MASS-TRANSPORT MODELS IN MULTICOMPONENT CONDENSATION

Explicit determination of the fluxes of condensing species and the energy transferred between the phases requires knowledge of state variables (composition, temperature, pressure) at the vapour-condensate interface. To simplify the computational procedure for estimating the interfacial state variables, two limiting cases of condensate flow have been assumed: (1) the condensate is considered as completely mixed with regard to composition in each cross-section of the condenser, and (2) the liquid phase is completely unmixed and the condensate flow can be regarded as fully segregated. Kinetic mathematical models have been developed for the two limiting cases describing the phenomena occurring during the condensation of multicomponent mixtures in which all components condense. The models derived serve as a basis for comparison of the two extreme mechanisms of mixing in the condensate layer. Simultaneously, computations have been performed employing the equilibrium model for the two limiting cases of the condensate flow. The results of the theoretical analysis and of the computed design of the condensers for a wide range of condensation intensities enable us to establish a correlation between the condensate flow model and the condenser geometry.