Abstract

A coupled computational fluid dynamics (CFD) and discrete element method (DEM) model was developed to analyze the fluid-particle and particle-particle interactions in a 3D liquid-solid fluidized bed (LSFB). The CFD-DEM model was validated using the Electrical Resistance Tomography (ERT) experimental method. ERT was employed to measure the bed-averaged particle volume fraction (BPVF) of 0.002 m glass beads fluidized with water for various particle numbers and flow rates. It was found that simulations employing the combination of the Gidaspow drag model with pressure gradient and virtual mass forces provided the least percentage error between experiments and simulations. It was also found that contact parameters must be calibrated to account for the particles being wet. The difference between simulations and experiments was 4.74%. The CFD-DEM model was also employed alongside stability analysis to investigate the hydrodynamic behavior within the LSFB and the intermediate flow regime for all cases studied.

Highlights

  • liquid-solid fluidized bed (LSFB) are attractive to processes that require operation at high fluid superficial velocities while maintaining a relatively homogeneous distribution of particles

  • The bubbling flow regime is achievable in certain LSFB systems, industrial LSFB processes rarely operate in this condition (Epstein, 2003)

  • The experimental results were used to develop a statistical model which could be employed as a tool to predict the bed-averaged particle volume fraction (BPVF) within the studied range of the design variables

Read more

Summary

Introduction

These sections were followed by an in-depth study which aims to compare the local particle volume fraction values obtained experimentally and through simulations (section 4.5). This flow regime is commonly referred to as the homogeneous regime This characteristic is specific to LSFBs as high fluid superficial velocities may cause other systems (i.e. gas-solid fluidized beds) to “bubble”. It is possible to operate LSFBs within an intermediate stability region, characterized by non-bubbling and nonhomogeneous flows Flows in this regime can provide a compromise between the homogeneity and rates of heat and mass transfer. Understanding the flow behavior in the intermediate stability flow regime is greatly beneficial to processes that require high exchange rates in transport phenomena, without drastically diminishing the evenness of the exchange

Objectives
Methods
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call