On the Contribution of Drag and Turbulent Stresses in the Fragmentation of Liquid Droplets: A Computational Study

Hossam  S. Aly; Yehia  A. Eldrainy; Tholudin  M. Lazim; Mohammad Nazri  Mohd Jaafar

Authors

Hossam S. Aly Department of Aeronautical Engineering, Faculty of Mechanical Engineering Universiti Teknologi Malaysia, MALAYSIA
Yehia A. Eldrainy Department of Aeronautical Engineering, Faculty of Mechanical Engineering Universiti Teknologi Malaysia, MALAYSIA
Tholudin M. Lazim Department of Aeronautical Engineering, Faculty of Mechanical Engineering Universiti Teknologi Malaysia, MALAYSIA
Mohammad Nazri Mohd Jaafar Department of Aeronautical Engineering, Faculty of Mechanical Engineering Universiti Teknologi Malaysia, MALAYSIA

Keywords:

CFD, population balance, atomization, droplet break-up, turbulence

Abstract

The primary objective of this study is to validate the numerical methods applied in the analysis of the plenum chamber in a swirling fluidized bed. The plenum chamber plays a vital role in pre-distributing the fluid evenly before it enters the distributor air gap, as maldistribution affects the performance of the fluidized bed. Comparison of the CFD predicted flow patterns and velocities calculated with the experimental data (using particle image velocimetry) are presented, and it is confirmed that good agreement is obtained. In a recent publication (Aly et al., Intl. Comm. Heat and Mass Transfer, 37(6) pp 618-623), the authors have developed a new mathematical model for predicting spray and atomization characteristics in an Eulerian-Eulerian framework. The model takes into account both the drag and turbulence induced fragmentation stresses. In the present paper, the authors investigate the relative contribution of the two different stresses in the break-up process using the new model for a case of a co-axial air-blast atomizer. The results show that turbulent stresses play the dominant role in the fragmentation of liquid droplets.