Effect of plenum chamber depth in a swirling fluidized bed

M A Hafiz,M F M Batcha,N Asmuin

doi:10.1088/1757-899x/50/1/012021

Abstract

This paper presents the numerical investigation via Computational Fluid Dynamic (CFD) to study the effect of plenum chamber depth on air flow a distribution in a swirling fluidized bed (SFB). A total of 9 simulations were conducted for 3 plenum chamber depths of 175 mm, 350 mm and 525 mm (below the distributor) for 3 different inlets: single, double and triple inlets. Air flow distribution was analyzed based on the tangential velocity distribution ad pressure drop at the distributor outlet. Statistical parameters used in characterizing the air flow distribution were standard deviation, skewness and kurtosis together with system pressure drop. An optimum plenum chamber depth has low statistical values, implying a uniform velocity distribution inside the bed while low pressure drops are necessary to reduce energy loss in the system. The findings yield that plenum chamber with 175 mm depth with via triple inlets suffices both criteria of high uniformity and low pressure drops.

Highlights

Fluidization is a process by which solid particles are made to behave like a fluid, by being suspended in a gas or liquid
The present work is an extension to the previous study by Batcha et al, 2013 whom have investigated the aerodynamics of a swirling fluidized bed (SFB) by taking into the effect of distributor design on velocity distribution and pressure drop inside the bed
The velocity and other parameters were based on the actual SFB system in the Faculty of Mechanical and Manufacturing Engineering, Universiti Tun Hussein Onn Malaysia (UTHM), which is currently used for drying of biomass

Summary

INTRODUCTION

Fluidization is a process by which solid particles are made to behave like a fluid, by being suspended in a gas or liquid. In contrast with conventional fluidization, in a SFB the fluidizing gas enters the bed at an inclination to the horizontal directed by a suitable design of distributor which as an array of blades with centre body, which forms annular opening as shown in Figure 1 (Batcha et al, 2012). The present work is an extension to the previous study by Batcha et al, 2013 whom have investigated the aerodynamics of a SFB by taking into the effect of distributor design on velocity distribution and pressure drop inside the bed. As for this study, particular attention is given on the plenum chamber design by varying its depth and number of inlet and their effect on aerodynamic characteristics of the bed. The findings are important to improve the plenum chamber design in the attempt to increase overall performance of the system

METHODOLOGY

AND DISCUSSION

Findings

CONCLUSION