A discrete particle model for flows of Group A particles in Geldart's classification is studied. In general, Group A particles are fine and light, so that the adhesion force has a strong effect on their fluidization behavior. Inter-particle adhesion force of Group A particle was measured first. Secondly, the DEM-CFD coupling simulation with the measured adhesion force was performed, and the simulated results were compared with the experimental data about a small-scale fluidized bed for verification of the simulation. It was found from the results that there were considerable differences between their flow patterns. In order to reveal the cause of the differences, the effect of the adhesion force in the contact force model was studied on the motion of a single particle colliding with a wall. From the analysis on the particle-wall collision process, it is found that the spring constant used in the DEM model has a large effect on the particle's sticking behavior on the wall. The dynamic adhesion force model is proposed based on the present analytical investigation, and it is found that the present model well expresses the effects of the adhesion force on the flow structure for the case of a small adhesion effect. (C) 2013 Elsevier B.V. All rights reserved.