Date of Award

4-1-2007

Degree Name

Doctor of Philosophy

Department

Paper Engineering, Chemical Engineering and Imaging (to 2013)

First Advisor

Dr. Dewei Qi

Second Advisor

Dr. Paul Dan Fleming

Third Advisor

Dr. David Peterson

Fourth Advisor

Dr. Jun Yong Zhu

Abstract

Fiber network is modeled as a three-dimensional random cylindrical fiber network. Nonlinear behavior of fluid flowing through the fiber network is numerically simulated by using the lattice Boltzmann (LB) method. Nonlinear relationship between the friction factor and the modified Reynolds number is simulated and analyzed by using the Fochheimer equation, which includes the quadratic term of velocity. There is a transition from linear to nonlinear region when the Reynolds numbers are sufficiently high, reflecting the inertial effect of the flows. The simulated permeability of such fiber network is compared to the experimental results and the finite element simulations.

Dynamic motions of fibers sedimenting and in shear flows are of great interest in the paper and pulp industry. Fibers are not just cylindrically shaped, but also curved. The sedimentation of curved fibers under gravity is studied. The aspect ratio, inertia of single curved fiber is found to affect the motion and orientation. Two and four fiber sedimentation under gravity are studied as well. The sedimentation of curved fiber is also compared with the sedimentation ofcylindrical fiber. The curvature and position are found to affect the sedimentation of multiple fibers in Newtonain flow. The lattice Boltzmann method is employed in this study. The numerical simulation is focused on migration and rotation of curved fibers and the interactions between fibers.

Access Setting

Dissertation-Open Access

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Engineering Commons

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