A Study of the Motion and Eruption of a Bubble at the Surface of a Two-Dimensional Fluidized Bed Using Particle Image Velocimetry (PIV)

详细信息    查看全文

• 作者：Christoph R. Mü ; ller ; John F. Davidson ; John S. Dennis ; Allan N. Hayhurst
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2007
• 出版时间：February 28, 2007
• 年：2007
• 卷：46
• 期：5
• 页码：1642 - 1652
• 全文大小：1175K
• 年卷期：v.46,no.5(February 28, 2007)
• ISSN：1520-5045

文摘

Particle image velocimety (PIV) was used to study the motion of a single bubble as it approached and thenbroke through the top surface of a two-dimensional (2D) gas-fluidized bed. A digital camera recorded themotion of individual particles; this led, via computer analysis, to a complete set of particle velocity vectorsaround the bubble, particularly its roof, as the bubble broke through the bed surface. These results revealedthe following: (1) The vorticity around the bubble is close to zero, except for the wake region at the bottomof the bubble, justifying the use of potential flow theory to predict the bubble motion around the bubble,apart from the wake. (2) Potential flow analysis, for a cylinder moving through infinite fluid, was used topredict the particle velocities for the bubble roof as the bubble broke through the surface of the bed. Thereis good agreement between theory and experiment for the roof velocities. (3) The experiments suggest thatbubble eruption occurs when the thickness of the roof is about three particle diameters. (4) Even after eruption,the potential flow theory gives quite a good prediction of the velocities of particles from the ruptured roof ofthe bubble.