Numerical and experimental analysis of particle strain and breakage in turbulent dispersions

This study deals with particle stress and breakage in turbulent flow. To estimate the particle stress, experimental set-up and computational fluid dynamics (CFD) are combined. The experimental set-up is used to examine the single drop breakage around a stirrer blade. The configuration of the breakage cell permits a study of particle break-up under variation of the mother droplet size and/or the flow velocity. CFD is used to investigate the flow pattern in this breakage cell. The CFD results are used to verify the flow field in the breakage cell as an acceptable model of a stirred tank. The results of the experimental investigations show that particle breakage takes place behind the stirrer blade. Referring to CFD simulations this region is clearly dominated by the highest energy dissipation rates. Also the shear gradients, which were calculated by CFD, show a major impact on the particle breakage.