Exploiting the drag reduction characteristics of dense pastes transporting in pipe with boundary liquids injection

When dense paste transports in pipe, the pressure loss is enormous. To make use of the wall slip phenomenon, different liquids were injected into the boundary layer in horizontal pipe and pressure loss per unit reduces. Through the pipe transportation tests, the effect of different factors to the resistance was analysed respectively, such as the thickness of boundary layer, the concentration of material, the type of drag reducer, the transport velocity and the flow rate. Results show that the drag reduction effect is much better with a higher thickness and lower transport velocity, and also obtains that PEO (Polyethylene oxide) solution as boundary layer is much more effective than water. With analysis of variance and significance test, the influence degree of the three main factors on the transport resistance is sorted as the thickness of the boundary layer, paste concentration, pipe diameter. The thickness of boundary layer has the greatest influence on the transport resistance. All conclusions provide a basis for how to use the boundary layer rationally in engineering paste pipeline transportation system.