Ph.D. Dissertation Defense by Marnico D. Deladisma
Friday, September 23, 2005

(Dr. Marc K. Smith, Chair)

"Lattice Boltzmann Simulation of a Cell-Polymer Bioreactor System"

Abstract

A numerical code that can simulate a cell-polymer bioreactor system has been developed using the lattice Boltzmann method. In general, bioreactors provide a three dimensional tissue culture environment that promotes cell proliferation and matrix production. Previously it has been shown that tissue constructs, which resemble articular cartilage in structure and function, can be cultured in vitro in a cell-polymer bioreactor system. A goal in this study was the accurate simulation of a rotating wall vessel (RWV) bioreactor containing moving constructs so that the fluid dynamics of the bioreactor can be better characterized.

Lattice Boltzmann is a flexible computation technique that allows for the simulation of a moving construct under various bioreactor conditions. The method predicts macroscopic hydrodynamics by considering virtual particle interactions. Since the numerical code used in this study was developed from scratch, the lattice Boltzmann implementation was first verified through a variety of 2D and 3D numerical studies testing boundary treatments, a method for grid refinement, and particle dynamics. The results were benchmarked against computations done with a commercial CFD package, FLUENT, and compared with analytic solutions and experimental data showing good agreement. The 2D and 3D simulations of the RWV bioreactor were then undertaken to validate the numerical code. The lattice Boltzmann simulations showed good agreement with experimental results in the areas of wake structure, dynamic construct behavior, and estimated shear stresses.