Hydrodynamics and rheological characterization upon the penetration process of a slotted plate into viscoplastic fluids

Abstract

Many industrial processes involve the moving of objects in viscoplastic fluids such as coating, drilling, and mixing. The understanding of the flow and the rheological behavior is beneficial for optimization of this process. However, viscoplastic fluids always demonstrate wall slip, presenting a challenge for flow analysis and rheological characterization. This study pays attention to the penetration process of a slotted plate into viscoplastic fluids. The force on the plate and the flow in the container are investigated by experiment and computational fluid dynamics and are modeled analytically. The shear stresses at the fluid–fluid interface at different penetration velocities are correlated with the pseudo-Herschel-Bulkley model to determine the yield stress. The non-Newtonian exponent and the consistency factor are calculated by the analytical model of flow. The penetration method is validated by comparing the flow curves obtained from this method with those from the parallel disk method and from the literature.