Gas–solid flow in a diffuser: Effect of inter-particle and particle

Senapati, S. K., & Dash, S. K. (2021). Gas–solid flow in a diffuser: Effect of inter-particle and particle–wall collisions. Particuology, 57, 187-200. https://doi.org/10.1016/j.partic.2021.01.006

Gas–solid flow in a diffuser: Effect of inter-particle and particle–wall collisions

Santosh Kumar Senapati ^*, Sukanta K. Dash

CFD Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Kharagpur, West Bengal, 721302, India

10.1016/j.partic.2021.01.006

Volume 57, August 2021, Pages 187-200

Received 2 October 2020, Revised 19 December 2020, Accepted 12 January 2021, Available online 10 February 2021, Version of Record 22 February 2021.

E-mail: senapatis431@gmail.com; sks90@iitkgp.ac.in

Highlights

• An increase in φ or a reduction in e_pp reduces pressure recovery.

• A higher φ or smaller e_pp enhances the particles’ trapping in recirculation zone.

• A higher φ or smaller e_pp enhances the recirculation zone’s strength and size.

• A higher φ or smaller e_pp strengthens the lateral displacement of the particles.

• Effects of φ and e_pp are insignificant for extremely small solid loading.

Abstract

This article investigates the role of the specularity coefficient (φ, the extent of the energy dissipation due to particle–wall collisions), inter-particle restitution coefficient (e_pp, the extent of the energy dissipation due to inter-particle collisions), and four combinations of these variables on the hydrodynamics, and the pressure recovery of the dilute gas–solid suspension in a diffuser. The investigation applies the two-fluid modeling approach along with the kinetic theory of the granular flow. The present investigation’s findings indicate that an increase in φ or a reduction in e_pp reduces the pressure recovery by weakening the reverse momentum transfer phenomenon, which is recognized as the primary means for the pressure recovery. Besides, in a gas–solid flow system, a higher φ or smaller e_pp enhances the particles’ trapping in the recirculation zone. The recirculation zone’s strength and size increase as φ increases or e_pp reduces. Moreover, an increase in the wall–particle and inter-particle interactions strengthens the sidewise displacement of the particles. The effect of the wall–particle and inter-particle interactions are insignificant for extremely small solid loading.

Graphical abstract

Keywords

Gas–solid flow; Diffuser; Particle–wall collision; Inter-particle collision; Pressure recovery; Reattachment length

文章导读