二维鼓泡床内气液流动特性实验与数值模拟

Experiment and numerical simulation of gas-liquid hydrodynamics in a two-dimensional gas-liquid bubble column

采用高速摄像法测量了0.20 m×0.02 m×2.00 m拟二维床内气泡尺寸分布和流型等变化规律,结果表明,随着表观气速的增大,鼓泡床内依次呈现均匀鼓泡区、过渡区和湍动区3种形式,以气泡个数概率表示的气泡尺寸分布呈对数正态分布。以计算流体力学软件ANSYS CFX 10.0为平台,采用k-ε湍流模型和GRACE曳力模型对气液鼓泡床内流体动力学行为展开了数值模拟,其结果与实验值比较吻合。研究表明,从多相流理论出发的计算流体力学模拟方法可以用来预报鼓泡床内流型过渡等流体动力学特性。

Flow regime pattern and bubble size distribution in a two-dimensional bubble column （0. 20 m × 0.02 m × 2.00 m） were investigated by combining experiment and simulation. The effects of gas inlet velocity on flow regime pattern and bubble size distribution were measured by high-speed digital camera. The results show that there exist dispersed bubble, transitional and coalesced bubble flow regime patterns, and the distributions of the bubble size can be described by the lognormal distribution function. According to two-fluid model, fluid dynamics were simulated by using commercial soft package ANSYS CFX 10.0 with κ-ε turbulence model and GRACE drag model. The numerical results are in fair agreement with the experimental data, which indicates that the numerical simulation of calculation fluid dynamics （CFD） can be used to predict hydrodynamic characteristics and to provide useful information for designing and scaling-up gas-liquid bubble columns.