抄録
Excess counterion enhanced the drag reduction in high shear flow.This enhancement was saturated when the molar concentration ratio of the counterion to surfactant was higher than ten.In the saturated condition of the counterion,the plots of drag reduction rate(DR) against wall shear stress was independent on the tube diameter over DRmax.When the flow rate increased from the start of drag reduction to its maximum,the plots of DR against Rew were reduced to a single curve for the small tubes of 0.9 and 2 mm.The surfactant of 1500 ppm was used with the counterion of ten-times higher molar concentration,and DR of 30 % was obtamed at the wall shear stress of 10^3 Pa,which corresponded to the shear rate of order 10^6 s^1.The surfactant solutions with excess counterion is effective in the application of high shear drag reduction.
