Herschel Bulkley Fluids Flow through Pipes — Lesson 4

This lesson covers the transport phenomena of non-Newtonian fluids, specifically focusing on Herschel-Bulkley fluids flow through pipes. It discusses the process of obtaining the velocity profile and volumetric flow rate equations for viscoplastic fluids flowing through pipes. The lesson also explains the derivation of equations for the case of Bingham plastic fluids and Herschel-Bulkley fluids. It further elaborates on the concept of viscoplastic fluids, their properties, and how they behave under different conditions. For instance, it explains how the material does not flow as long as the applied stress is less than the characteristic yield stress. The lesson concludes with an example problem on the derivation for the case of Herschel-Bulkley fluid.

Video Highlights

02:42 - Explanation of the concept of yield stress and its role in the flow of viscoplastic fluids.
13:02 - Explanation of the equation of motion for the flow of Herschel-Bulkley fluids through pipes.
22:00 - Derivation of the velocity profile for the deforming and non-deforming regions of the flow of Herschel-Bulkley fluids.
31:19 - Calculation of the volumetric flow rate and average velocity for the flow of Herschel-Bulkley fluids.
40:28 - Solution of an example problem on the flow of Herschel-Bulkley fluids through pipes.

Key Takeaways

• The velocity profile and volumetric flow rate equations for viscoplastic fluids flowing through pipes can be obtained through specific derivations.
• Viscoplastic fluids have characteristic properties such as density, viscosity, and yield stress.
• The material of viscoplastic fluids does not flow unless the applied stress is greater than the characteristic yield stress.
• The velocity profile of viscoplastic fluids consists of two regions: a solid plug-like region and a deforming fluid region.
• The pressure drop, plug velocity, and size of the plug can be calculated using the derived equations.