Effective Wall Slip in Couette and Parallel Plates Flow of Drag-Reducing Surfactant Solutions

This paper presents experimental results of the study on the rheological properties of drag-reducing surfactant solutions. It is the main objective of the present work to establish the possibility of wall slip corrections for Couette and parallel plates rheometers. In addition, methodology of samples preparation of aqueous surfactant solutions to rheological measurements is presented. In the study the cationic surfactant cethyltrimethylammonium chloride (CTAC) was used. The additive enhancing micellar association was sodium salicylate (NaSal). In solutions used the molar ratio of CTAC to NaSal was in the range from 1 to 2. Concentrations of the solutions were equal to 1000 and 6000 ppm. Experimental data presented show that during the flow curve measurements for surfactant solutions there is a possibility of occurrence an effective wall slip. Correcting measurement results by the use of simple methods does not provide guaranties to obtain real flow curve characteristics. Best solution seems to be in using the measuring systems with rough surfaces.