加压流化床流化性质的实验与模拟研究

在二维射流流化床装置中,考察了压力对颗粒和气泡运动的影响规律.通过使用摄像技术详细的记录了压力下气泡的行为,并对其进行了分析,由此解决了较高压力下测量流态化性质较为困难的问题.数值研究通过CFD双欧拉模型模拟了带有V形分布器和中心射流的二维流化床内压力对气泡大小、床的膨胀率和射流深度的影响.实验和理论结果表明,在加压状态下,射流气速和分布板气速对气泡的产生、大小及形状有不同的影响.在较高的操作压力下,射流气速增加,气泡变长;分布器气速增大,气泡则变大;射流高度随着分布器气速的增加而降低.模拟结果与实验数据吻合较好,由此该模型为研究较高操作压力下射流流化床流化性质提供了有利的工具.

Experiments and simulation of fluidization properties in a pressurized jetting fluidized bed

The behavior of particles and bubbles in a two-dimensional jetting fluidized bed included in a pressured vessel was investigated experimentally by using the CCD camera technology that can detailedly record the behavior of bubbles. Eulerian-Eulerian model was used to simulate the hydrodynamics of a pressurized jetting fluidized bed with a central jet and V-shaped distributor. The influence of gas velocity on the size of bubble, bed expansion ratio and jet penetration height at higher pressure was studied. Both experimental and simulation l results clearly indicate that the jet height decreases and the bubbles become more round when the gas-velocity of distributor is increased at higher pressure. When the jetting gas-velocity is increased, the jet height increases and the bubbles become slender. It has been verified that the result from hydrodynamic model shows a good agreement with experimental data, which suggests that the model can be used to study the fluidization properties in the pressurized fluidized bed.