Anomalous Flow Properties of Several Types of Rod-Like Micelle Surfactant Solutions Passing through Small Apertures

Abstract

We previously investigated anomalous phenomena in pressure drops of (drag-reducing) rod-like micelle surfactant solutions passing small apertures. Compared with water results, pressure drops of rod-like micelle surfactant solutions rose steeply at any Reynolds number. The anomalous pressure drops was dependence of molar concentration ratio, which was relationship between molar concentration of cationic surfactant solution and those of counter ion. For only the ratio = 1.0, anomaly of pressure drops was obtained. However, the mechanism was not clear for using only 1 surfactant solution and discussing non-Newtonian viscosity. In this situation, pressure drop was measured with constant flow rate because of investigating flow properties of 2 types of rod-like micelle surfactant solutions passing through small apertures with inner diameter (characteristic length) ranging 100 μm to 1000 μm (= 1.0 mm). The resultant pressure drops of water agreed with the predictions and previous ones passing through small apertures. The flow properties of rod-like micelle surfactant solution which was used in our previous study were similar to previous ones. However, pressure drops of another rod-like micelle surfactant solution were different and increased invariably. We measured storage modulus and loss modulus of the used rod-like micelle surfactant solutions and estimated relaxation time for discussing elastic properties. For plotting dimensionless pressure drops against Weissenberg number (Wi), it found that anomalous pressure drops of rod-like micelle surfactant solutions appeared in Wi > 10 0 . We discussed thus that the phenomena were caused by elasticity.