On the mechanism of the plug formation in pumping concentrated water-coal suspensions

Concentrated water-coal suspension flow (approximate particle size 20-300 μm) was studied in a laminar regime. Explanation of the pipeline plug formation mechanism is the most significant result of the presented paper. It is shown, that solid phase rate of the slurry has local maximum at increasing concentration in the pipeline. At first the rate of this phase increases but then decreases, because suspension viscosity and resistance to motion begin to increase very quickly. The pipeline blockage occurs in the case when the entrance slurry concentration exceeds the one defined by the solid phase rate maximum.