Study of the effect of liquid bridges on the dynamic behavior of two colliding tablets using DEM

By incorporating a viscous liquid force model into DEM simulations, the effect of liquid bridging between two tablets during a collision was studied. It was shown that when compared to the viscous force, the capillary force is several orders of magnitude smaller. In order to predict the capture of a falling tablet by the liquid bridge, it was necessary to adjust the limiting separation distance used in the viscous force model. Comparison of experimental results with the simulations, using oils with viscosities in the range of 100–1,000 cP, showed that there was a linear relationship between the limiting separation distance and the viscosity of the silicone oils. This viscosity-dependent separation distance varied in the range of 1–6 mm.

A series of experiments was performed in which two tablets, with their surfaces coated with viscous oils, collided and the impact was simulated using a discrete element model (DEM). In order to correlate the results of the model with the experiments, the limiting separation distance between the tablets using a viscous force model was determined. This separation distance was found to be a function of the viscosity of the liquid and varied in the range of 1 to 6 mm.Figure optionsDownload as PowerPoint slide