Mechanisms of dispersion and friction in coarse-slurry flows

Investigatorprof. Dr. Ing. Václav Matoušek, Ph.D.
Duration2006 - 2008

The main objectives of the project are to improve an understanding of mechanisms governing flows of coarse slurries (slurries of particles larger than say 100 micron) and to improve abilities to model coarse-slurry flows. It is well known that there is a close relationship between the distribution of solid particles in the near-boundary area of slurry flow and the friction caused by particles at the boundary of a conduit (pipe or channel). However, very little is known about the nature and mechanism of the particle friction, particularly if particles are not in permanent contact with the boundary. Likewise, a contemporary knowledge is very limited of the mechanism of solids dispersion in the slurry flow near the boundary. Recently, the applicant conducted a number of rather sophisticated experiments with coarse slurry flows in pipes of different slopes in the Laboratory of Dredging Engineering of the TU Delft (Netherlands). In the proposed project, his data will be analyzed in order to elucidate principles of friction and dispersion of solid particles in flowing coarse slurries. The analysis will be instrumental to a mathematical description of friction- and dispersion mechanisms in the region adjacent to a flow boundary. An existing predictive overall model for coarse slurry flows will be improved by implementing new developed formulae for the studied mechanisms. The research results will improve the modeling of suspension flows in pipes, sewer systems and open channels.