Gas-liquid flow in bubble columns and loop reactors: Part II. Comparison of detailed experiments and flow simulations

Gas-liquid bubble flow was studied in a flat bubble column with rectangular cross-section and essentially two-dimensional flow structure. Both a bubble column and an airlift loop reactor arrangement have been considered. The experimental techniques used comprise visual observation of the flow structure and photographic documentation of the bubble distribution as Well as detailed measurements of the two-phase flow characteristics at distinct levels over the column width. The experimental results arc compared with numerical simulations based upon the dynamic laminar two-dimensional two-phase Euler-Euler model presented in Part I. The steady state as well as the transient behaviour was well reproduced in the simulations. Good quantitative agreement could be obtained if the value of the laminar viscosity used was increased by a factor 100 to account for the influence of turbulent viscosity. The standard k-epsilon model results in a much higher increase in the viscosity which does not give satisfactory agreement in the range of the bubble flow regime considered.