Comparison of Experimentally Determined Parameters of Particle Motion with Predictions from a New MATLAB TM-based DEM Code

摘要

When coating tablets or particles in a rotating pan coater, the regularity with which particles pass through the spray plays an important role in determining the overall uniformity of coating for the batch of material being coated. The current work uses data taken using a digital imaging system equipped for machine vision at a framing rate of 25 Hz. The presence of a white tracer particle (9mm polystyrene sphere) at the surface of a moving bed of identical black particles is monitored using the imaging system. Information including the time spent at the surface, the number of passes, the visible projected area of the sphere, and the velocities parallel and perpendicular to the moving bed are obtained with the imaging system. Results from the experimental work are compared with predictions using a DEM code developed to run in the MATLAB TM environment. The code was developed as a stand-alone program and provides simulation, visualization, post processing statistical analysis of particle movement, and the ability to track individual particles. Issues relating to how long to perform simulations to eliminate the effect of starting conditions and the effect of different parameters for the contact mechanics are addressed.