Transport of Coarse Particles in a Fine Suspension Medium

抄録

The rheology of suspensions of coarse particles in non-Newtonian fluidshas not been the subject of much investigation. There are distinct advantagesin using non-Newtonian carrier fluids in the transportation of solids, forexample in coal slurry transport. The objective of this work is to investigatethe flow behaviour exhibited by a concentrated mixture of coarse particles ina medium consisting of suspensions of fine particles. Steady state viscositymeasurements of suspensions of mono-sized coal, ballotini and styreneacrilonitrileparticles suspended in a non-Newtonian bentonite clay carrier fluid havebeen made using a Contraves Rheomat 115 rheometer. Measurements werecarried out with various particle concentrations and shear rates ranging from 2.22s^-1 to 345s^-1. It was found that variation of viscosity due to coarse particlesize did not follow any trend. It is thougth that this behaviour in due tothe interaction between the clay flocs and the coarse particles. Modellingwork assuming interacting coarse particles and flocs coexisting as in a bimodalmixture was shown to simulate this behaviour.