Date of Award

12-2001

Degree Name

Master of Science

Department

Chemical and Paper Engineering

First Advisor

Dr. Dewei Qi

Second Advisor

Dr. David Peterson

Third Advisor

Dr. Raja Aravamuthan

Access Setting

Masters Thesis-Open Access

Abstract

Lateral migration of solid particles in shear flow is observed in various industrial applications. Suspensions in a blade coater, a device used to apply coating pigment to a base paper to improve paper properties, is an example. Particle hydrodynamics will affect the quality of coated paper and runnability of the coater especially when the speed of the coating machine is very high or the pigment concentration is increased.

Many factors will affect the particle migration. The wall repulsion or lubrication effect forces the particle away from a wall to the channel center. The inertial effects are increased by increasing the particle Reynolds number and influence the total forces and torque that exert on the particle. Thus the lateral migration and the final equilibrium position are changed.

The results show that, with a zero or low particle Reynolds number, the equilibrium position of the particle is at the channel center and the particle velocity equals the fluid velocity. When the particle Reynolds number and the confinement ratio increases, the equilibrium position is shifted from the channel center to a position close to the wall and the particle velocity is found to lead the fluid velocity. The particle shape affects the migration and the final equilibrium position. An elliptical particle has a higher off-center distance than a spherical particle.

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