关键词: 鼓泡塔, 列管内构件, 两相流, 计算流体力学, 湍流模型

Abstract: The accuracy of CFD simulation results for bubble columns depends on closure models, such as interphase force models and turbulence models. Most of the previous reports were for empty column without internals, and currently, there is a lack of studies related to bubble column with internals. This study examined the effects of six commonly used turbulence models (Standard k-ε, RNG k-ε, Realizable k-ε, Standard k-ω, SST k-ω, and RSM) on the hydrodynamics in the pilot-scale bubble columns without internals and with tube bundles. The results showed that the RSM predicted significantly higher for turbulent kinetic energy, turbulent dissipation rate, and turbulent viscosity in the empty column compared to eddy viscosity models (k-ε and k-ω models). However, this difference was considerably reduced in the bubble column with tube bundles, and the tube bundles significantly suppressed the turbulence intensity in the liquid phase. Meanwhile, by comparing the simulated gas holdup and axial liquid velocity values with experimental data, it was found that the eddy viscosity models accurately predicted the gas holdup in the central region of the empty column, while the RSM accurately predicted the gas holdup in all regions except the central region. However, the radial distribution of gas holdup predicted by six turbulence models in the bubble column with tube bundles was almost identical, with accurately predicting the gas holdup only in the 0.5<r/R<0.7 region. The Realizable k-ε model's predictions of axial liquid velocity in both empty column and the bubble columns with tube bundles were in good agreement with experimental data, significantly outperforming other turbulence models. Therefore, it was recommended to use the Realizable k-ε model for future simulations of hydrodynamics in bubble columns.

Key words: bubble column, internal tube bundles, two-phase flow, computational fluid dynamics, turbulence model