Experimental Study On Drag Reduction Of Hydraulic Transport Of Solid In Tube With CTAB

The presence of small amounts of certain polymers or surfactants in water is result in considerable drag reduction in turbulent flow which is called as additive drag-reducing fluid. Compared with the polymer, surfactant solution has the strong self-repairing ability after the mechanical degradation so that it is suitable for application in closed circulatory system and the pipe flow transportation across the long distance. Compared with CTAB aqueous solution, the research of drag reduction behaviors of surfactant in hydraulic transport of solid has not yet been published so far.In order to probe into the drag-reducing behaviors of surfactant in hydraulic transport of solid, the paper analyzes the relationship between the hydraulic gradient of solid-liquid phases and solid particles concentration and size by a half open-loop system, then studies the drag-reducing behaviors of CTAB in water and hydraulic transport of solid by using a circular stainless steel pipe with 10 mm diameter.The hydraulic gradient of solid-liquid phases flow at different concentration of solid particles and size of particles were measured with a half open-loop system. The results showed that the hydraulic gradient of solid-liquid phases flow increased with the increasing of solid particles concentration under the same size of solid particles. At the same concentration of solid particles, the hydraulic gradient of solid-liquid phases flow decreases with the increase of the diameter of solid particles.The experimental result of CTAB reduction shows that when the CTAB concentration exceeds a certain critical value then drags reduction occurs in hydraulic transportation of solid particles. It is noteworthy that solid concentration and particle size must be remains unchanged at the same time. When the solid concentration and particle size are keep in the same value respectively, the hydraulic gradient of solid-liquid two-phase flow decreased with the increasing of CTAB concentration. In the condition of the same concentration of CTAB, the drag reduction ability of CTAB in hydraulic transportation of solid particles decreased significantly with the increase of the concentration of solid particles, and decreased with decreasing particle size. The main reason of CTAB reduction ability change is the changes in the flow field of shear stress which caused by solid concentration and particle size.The technology of the CTAB drag reduction was applied in the hydraulic transport of solid particles, and could save energy more efficiently in solid-liquid phases flow. This has important meaning for long distance pipeline hydraulic transport of solid particles.