关键词: 鼓泡床, 流动, 计算流体力学, 双流体模型, 静电效应, 气泡特性, 模拟

Abstract:

The present paper studied the effects of electrostatics on gas-solids hydrodynamics and bubble characteristics of gas-solids bubbling bed with and without immersed horizontal tubes by applying the two-fluid model coupling with the electrostatic model. At first, the two-fluid model without electrostatic field was adopted to simulate the hydrodynamics in the gas-solids bubbling bed with and without immersed horizontal tubes. Further coupled with the electrostatic model, the effects of electrostatics on bubble distribution characteristics in the gas-solids bubbling bed with and without the immersed horizontal tubes were investigated. The results demonstrated that in the electrostatic field conditions, the two-fluid model can be used to predict gas-solid flow conditions, the bubble diameter, and bubble riser velocity for gas-solids bubbling bed with and without immersed horizontal tubes. However, the immersed horizontal tubes in gas-solids bubbling bed caused an intense disturbance of gas-solids, making a concussion in the distribution of the bubble diameter and bubble riser velocity. The electrostatics did not have a large effect on the average solids holdup of the bed, but showed a greater impact on the bubble characteristics. The electrostatics decreased the number of bubbles of the gas-solids bubbling bed without the immersed horizontal tubes and made more number of bubbles be concentrated in the lower region of the gas-solids bubbling bed with the immersed horizontal tubes and more number of large bubbles be located in the upper part of the gas-solids bubbling bed with the immersed horizontal tubes.

Key words: bubbling bed, flow, computational fluid dynamics (CFD), two-fluid model, electrostatic effects, bubble hydrodynamics, simulation