Rheological Characterization of Drag-Reducing Cationic Surfactant Solution: Shear and Elongational Viscosities of Dilute Solutions

Shear viscosities of one kind of turbulent drag-reducing cationic surfactant solution, Cetyltrimethyl ammonium chloride (CTAC)/Sodium salicylate (NaSal) aqueous solution, were experimentally investigated by use of a stress controlled Reometer. The concentration and temperature of the solution ranged from 50 to 200 ppm and 20 to 40°C, respectively. The Giesekus model was found to fit the measured shear viscosities well for different temperatures and concentrations of the surfactant solution and the model parameter values obtained by fitting were correlated with temperature at certain solution concentrations. The temperature was found to have a large influence on the viscoelasticity of the surfactant solution. By using the model parameters obtained from the correlations, 70 percent of the measured shear viscosities agreed with the prediction by the Giesekus model within ±27.3 percent. The elongational viscosities of CTAC/NaSal surfactant solution were also experimentally investigated by use of an oppositing jet Reometer. The measured data were lower than the prediction by the Giesekus model.