Viscoplastic fluid displacement flow in pipes : the effects of pipe axial

Abstract

This study investigates experimentally the influence of a pipe axial rotation on the buoyant miscible displacement flow of a Newtonian fluid by a viscoplastic fluid in a vertical pipe. Within the range of operational flow and fluid parameters examined in this study, the emergence of separation and nonseparation flow regimes was observed as the heavy fluid was imposed. The effects of the pipe axial rotation on these flow regimes and front velocities were compared. The results indicate that the addition of axial rotation to the pipe at low values of the imposed flow rate can result a transition from the separation regime to the non-separation regime. However, for high values of the imposed velocity, the displacement flow regime remains largely unchanged when the pipe axial rotation is applied. Additionally, the displacement front velocity (𝑉 ̂𝑓) decreases in the domain where the separation regime occurs when rotational speed is increased.