Bubble growth model in uniformly superheated binary liquid mixture

Abstract

A novel model was developed to investigate the fundamental heat transfer and mass diffusion mechanisms of bubble growth in uniformly superheated ethanol–water mixture. In the proposed model, the energy equation was applied coupling with the quadratic temperature distribution within the thermal boundary layer. The mass diffusion effect was accounted by the introduction of species conservation equation in combination with the quadratic concentration distribution within the concentration boundary layer. Peng-Robinson equation of state and activity coefficient calculation were also adopted for the estimation of vapor-liquid equilibrium. In the present study, the maximum mass diffusion limited growth rate was proposed to quantify and illustrate the effect of mass diffusion on bubble growth. The results show that the bubble growth process in a binary mixture can be divided into three distinctive stages. The later stage of bubble growth is mainly subject to mass diffusion and partly to heat transfer at low ethanol concentrations.