Measuring inline velocity profile of shampoo by electrical resistance tomography (ERT)

The rheological properties of fluid systems govern the efficiency and quality of a production process. For certain materials, i.e. non-Newtonian fluids, The change in shear rate leads to the change of local viscosity, while the conductivity also changes due to the change in micro-structure of the material by varying shear rate. This paper provides a method of measuring the local velocity of shampoo in an in-line pipeline loop using electrical resistance tomography (ERT). Boundary voltages are measured by ITS P2000 ERT system and processed into a 2-D conductivity distribution in a MATLAB based ERT tool kitEIDORS. Linear-back projection (LBP) method is used for solving the inverse problem. The change in shear rate leads to a micro-structure change in the shampoo, resulting in an annular conductivity distribution in the cross-sectional view of the pipeline. By varying the flow rate, different changes in conductivity can be obtained. A velocity profile of shampoo is calculated based on the change in conductivity, giving a method to realise in-line rheometer by ERT.