Modeling of bubble dynamics and heat transfer in polydispersed two-phase turbulent flow in a vertical pipe

Abstract

The numerical results on the flow, bubble distributions and heat transfer in a bubbly polydispersed upward flow in a pipe are presented. The mathematical model is based on the Eulerian approach with considering the back effects of bubbles on the mean and turbulent characteristics of the carrier fluid phase. The model is coupled with the method of δ-function approximation. The model takes into account the interphase momentum transfer, bubble breakup and coalescence processes. The set of axisymmetrical RANS equations is used for modeling two-phase bubbly flows. Turbulence of the carrier fluid phase is predicted using the Reynolds stress transport model. The effect of variation in the gas volumetric flow rate ratio, inlet mean fluid temperature, and its velocity on the flow structure and heat transfer in the two-phase flow is analyzed. The addition of air bubbles results in a significant increase in the heat transfer rate (up to three times) and the effect augments by increasing the gas volumetric flow rate ratio. The numerical simulations show a good agreement with the experimental and numerical results of other authors.