A new heat transfer model based on non-equilibrium theory for annular flow condensation-part Ⅱ: Ternary zeotropic mixtures

Abstract

In the past decades, attention has been paid to the flowcondensation heat transfer characteristics of zeotropic mixtures, but most of the research has been carried out on binary mixtures, with very few studies performed on multicomponent mixtures that contain ternary and more components. The condensing process of multicomponent mixtures is significantly more complex since there are interactions between the components except for mixture effects, and these mechanisms are still unclear. Therefore, existing prediction methods either being computationally complicated or fail to accurately describe the condensation characteristics of multicomponent zeotropic mixtures. Focused on this issue, a new heat transfer correlation for ternary zeotropic mixtures in annular flow condensation was proposed based on our previously developed heat transfer model for binary zeotropic mixtures. The ternary mixture is regarded as a combination of two binary mixtures by analyzing the relationship of the condensation rate difference between components and the concentration gradient, and binary interaction coefficients are introduced to estimate the relative contribution of the two independent concentration gradients in the condensing vapor of ternary zeotropic mixtures. The newly developed correlation is simple and agrees well with the condensation heat transfer coefficients of ternary zeotropic mixtures, with an average relative deviation (MRD) of -1.6 %, an average absolute relative deviation (MARD) of 13.9 %, and 90.2 % of the data points falling within ±30 % deviation band for a total of 307 annular flow data.