CFD Modeling of Multiphase Turbulent Flows in a Bubble Column Reactor

Identifier:  TDX:3269

Handle: https://hdl.handle.net/20.500.11797/TDX3269

Authors:  Goraki Fard, Mojtaba

Abstract:
This work presents numerical study turbulent two-phase flows in a 3D bubble column reactor using different models at different scales. The focus is first set on the hydrodynamics, flow regime transitions and mass transfer using the Euler-Euler mixture k-ε model at wide ranges of superficial gas velocities. The emphasis is to assess the performance of this model and the analysis of the flow regime transitions and the transient flow behavior inside the bubble column reactor. The quantification of the interfacial forces at different parts of the reactor are presented. Different models of the overall mass transfer coefficient estimation, namely the slip penetration model and the eddy cell model, are compared against the experimental data to analyze the mass transfer. The results reveal some of the characteristic features of homogeneous and heterogeneous flow regimes on the liquid circulation, gas holdup, turbulent fluctuations and gas-liquid mass transfer. For transient and turbulent flow regimes, Euler-Euler large eddy simulations were used for a reliable scale resolution. The flow is more dynamic, and more details of the instantaneous local flow structure have been obtained including large-scale structures and vortices developed in the bubble plume edge.