화학공학소재연구정보센터
KAGAKU KOGAKU RONBUNSHU, Vol.34, No.3, 321-330, 2008
Simulation of Drying Process of Suspensions Containing Fine Solid Particles Using DEM and CIP method
A method to simulate the drying behavior of suspensions containing fine solid particles was developed to obtain information on the control of structure in a dried particle packing bed. The method is a combination of the discrete element method for analyzing particle behavior and the constrained interpolation profile method for analyzing gas-liquid multiphase flow. Interaction forces between fine particles such as mechanical contact, cohesion, Van der Waals and electrostatic forces caused by the double electric layer and the interaction between particles and fluid such as lubricant, Brownian force and surface tension acting on the floating particles on a liquid surface were taken into consideration as forces acting off the suspended fine particles during drying of suspensions. Drying behaviors of suspensions on a flat substrate were simulated under various dispersion conditions of fine particles and various drying rates to confirm the reliability of the developed simulation method. The particle arrangement at the top surface of the particle packing bed obtained by simulation was in good agreement with the experimental one. The relationship between the behavior of fine particles during drying of suspensions and the structure in the dried particle packing bed was investigated microscopically using the developed simulation method. The particle arrangement in the first particle layer deposited on a substrate greatly affects the particle packing structure. The increase of contact force between particles with increasing of drying rate leads to disorder of particle the packing structure.