Numerical investigation of gas bubble behavior in tapered fluidized beds--颗粒学报PARTICUOLOGY

Khodabandehlou, R., Askaripour, H., & Molaei Dehkordi, A. (2018). Numerical investigation of gas bubble behavior in tapered fluidized beds. Particuology, 38, 152-164. https://doi.org/10.1016/j.partic.2017.05.013

Numerical investigation of gas bubble behavior in tapered fluidized beds

Ramin Khodabandehlou, Hossein Askaripour, Asghar Molaei Dehkordi ^*

Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11155-9465, Tehran, Iran

10.1016/j.partic.2017.05.013

Volume 38, June 2018, Pages 152-164

Received 9 April 2017, Revised 25 May 2017, Accepted 25 May 2017, Available online 25 September 2017, Version of Record 2 April 2018.

E-mail: amolaeid@sharif.edu; amdehkordi@yahoo.com

Highlights

• Size distribution and bubble rising velocity in tapered fluidized beds were studied.

• Increasing the apex angle increased the fraction of gas bubbles with large size.

• Increasing the apex angle decreased the bubble rising velocity along the bed height.

• As particle size increased, the fraction of gas bubbles with large size decreased.

• Increasing particle density slightly influenced the distribution of bubble size.

Abstract

In this article, the behavior of gas bubbles in tapered fluidized beds is investigated with the use of a two-fluid model incorporating kinetic theory of granular flow. The effects of various parameters such as apex angle, particle size, and particle density on the size distribution and the rise velocity of gas bubbles were examined. In addition, the simulation results for the bubble fraction and axial velocity of gas bubbles were compared with experimental data reported in the literature and good agreement was observed. As the apex angle was increased, the fraction of gas bubbles with large sizes increased and the fraction of bubbles with small sizes decreased. As the particle size increased, the fraction of gas bubbles with large diameters decreased; however, the fraction of bubbles with medium diameters increased. The obtained results clearly indicate that an increased solid density increased the bubble rise velocity up to a specified height and reduced the velocity at larger heights, in tapered fluidized beds.

Graphical abstract

Keywords

Tapered fluidized beds; Apex angle; Particle size and density; Bubble size distribution; Rise velocity of bubbles

文章导读