Computational modelling of flows in porous scaffold materials using a lattice Boltzmann method
Porous scaffold materials have been widely used in biological tissue engineering. It is known that fluid flow in porous media significantly increases the supply of oxygen and other nutrients to cells seeded in the porous material, and speeds up the clearance of metabolic end products. Local shear stress distribution is a function of media flow rate, viscosity and the porous scaffold micro-structure. This research project aims to investigate fluid movement in porous structures by using a lattice Boltzmann method. This new numerical method models the fluid as a collection of identical particles with collision and propagation procedures, and has been shown as an alternative and efficient numerical solver of Navier-Stokes equations, in particular for flows in complex geometries. The numerical scheme is verified using flow in a two-dimensional channel, as well as in three-dimensional ducts with constant shapes, where analytical solutions are available. 2D porous structures originated from micro-CT images are then used to study the flow and wall shear stress distribution. One of the advantages of the lattice Boltzmann method is that the shear stress can be computed directly from the local distribution function and has the same accuracy with the velocity profile. Fluid patterns and wall shear stress distribution in 3D porous structures, which 6 are reconstructed from the micro-tomographic slices, have been investigated under different flow rates, viscosity and geometrical structures. Results from this project demonstrate that lattice Boltzmann method is suitable for flow modelling in scaffold materials. It provides detailed information on localized velocity and stress distributions, which can be used to improve the design of the scaffold for cell and tissue engineering.
- Theses