Applicability of the standard k-epsilon turbulence model to the dynamic simulation of bubble columns: Part I. Detailed numerical simulations

Detailed simulation results for the test case of a locally aerated hat bubb le column for laminar and turbulent models of Euler-Euler type in two and t hree dimensions are presented for different space resolutions. The flow str ucture observed in the experiment has an instationary turbulent character. If the 2D laminar model is applied for calculations the dynamic character o f the flow field can be resolved, but the simulation results depend strongl y on the space resolution used. If the 2D k-epsilon turbulence model is use d instead, the grid independent solution can be achieved on a relatively co arse grid, but the dynamic nature of the flow is not reproduced in the simu lation. Only if the 3D turbulent model is used, the simulation results show a good agreement with experiments. This means, that the three-dimensional effects which are neglected in the 2D simulation have a strong influence on the numerical solution. Further, the influence of the discretization on th e accuracy of the solution is discussed, and a comparison between results o btained with 2D Euler-Euler and Euler-Lagrange models is presented. (C) 199 9 Elsevier Science Ltd. All rights reserved.