Dissertation Defenses

Doctoral Dissertation Announcement

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Candidate: Xiaoying Rong

Degree of: Doctor of Philosophy

Department:Paper Engineering, Chemical Engineering, and Imaging

Title: Numerical Study of Flow in Three-dimensional Fiber Network and Curved Fiber Sedimentation by Lattice Boltzmann Method

Committee:
Dr. Dewei Qi, Chair
Dr. Paul Dan Fleming
Dr. David Peterson
Dr. Jun Yong Zhu

Date: Friday, March 23, 2007 10:00 a.m. – 12:00 p.m.
Parkview Campus, A-217

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 of cylindrical fiber. 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.