关键词: 浆态鼓泡塔, 流体力学模型, 网格型内构件

Abstract: Screen is one of the simplest resistance internals for improving velocity profile in a bubble column. In this paper axial liquid velocity and gas hold up distributions along the radial of ?500×5000 bubble column with multi-layer screens were measured by Pavlov tube and conductivity probe respectively. The experimental observations showed that the lateral screen internals can remarkably reduce the ascending liquid velocity in the core region, resulted in an improvement of flow profiles. The smaller the screen hole is, the more remarkable the resistance effect will be, and the higher the average gas hold up is. A one dimensional CFD model similar to that applied to pipe bundle internals was developed, and the damping effect of screen internals on the liquid was regarded as volumetric sources of momentum, turbulent kinetic energy and dissipation. The value of parameters appeared in turbulent energy dissipation equation were different form the model of pipe bundle internals, and they were estimated as c3=1.0，c4=1.3 by comparison with experimental data. The calculated results agreed well with the experimental data. The present model provided a effective tool in simulation of damping effect of multi-layer screens internals in bubble columns.

Key words: bubble column, hydrodynamic model, multilayer screens