Characteristics of flow of non-Newtonian fluid in a wavy-walled tube for pulsatile flow

The flow state has important impact on the heat and mass transfer. Hence pressure differences and flow visualization experiment were carried out in a wavy-walled tube with polyacrylamide solution, which is a kind of typical non-Newtonian fluid, for pulsatile flow field. Compared with water, the moderate concentration of polymer solution can reduce the frictional resistance and natural transition Reynolds number. Stable and unstable states of flow patterns are found in wavy-walled tube during one oscillation cycle. Based on the experimental results, the fluid mixing under the conditions of pulsating flow is better than under the conditions of steady flow at the same net Reynolds number, which means that mass transfer have been enhanced significantly under the conditions of pulsating flow.