Experimental Study On Drag-Reducing Of CTAB In Water And Hydraulic Transport Of Solid

The additive drag-reduction phenomenon, which can lead to greatreduction of turbulent drag by adding a little polymer and surfactant intothe hydrosoluble Newtonian fluid,has been called TOMS effect.Becausethe polymer which is not the same as the surfactant don’t enduremechanical degradation, as a new turbulent drag-reducing technology,theturbulent drag-reduction of surfactant is applied in the transport field ofaqueous phase liquid so as to reduce the power consumption oftransportation.So the research of the surfactant drag-reduction ofturbulent is becoming promising topic in the field of reducing drag andsaving energy all over the world.However, domestic research of cetyltri-methylammonium bromide and the surfactant drag-reducing effectof hydraulic transport of solid is rather little.Influence of concentration of solution and molar ratio of NaSal ondrag-reducing effect have been experimentally investigated with a halfopen loop system in this paper.The results indicate that critical Reynoldsnumber and scope of drag-reduction improves with increasingconcentration of solution. The drag-reducing effect of CTAB improveswith Reynolds number increased under the same concentration ofsolution.When Re exceeds a certain value, the drag-reducing effect startto decline,and back to the solvent level of Newtonian fluid finally. Theexperiment of molar ratio of NaSal show that, the variation trend of thecurve of each molar ratio is consistent. For achieving the best drag-reduction there is a optimum ratio.In the drag-reducing test of hydraulic transport of solid,fanningfrictional factor decreases with concentration of CTAB increased underthe same mass ratio of sand.Fanning frictional factor augments withmass ratio of sand increased under the same concentration of CTAB,andthe drag-reducing effect weakens with mass ratio of sand increased underthe same concentration of CTAB.The research of the drag-reducing characteristic of CTAB providesan useful reference for applying CTAB to practical projects.Theexperimental study of surfactant drag-reduction was conducted in the hydraulic transport of solid,which has important implications for longdistance transportation of silt.