Porous media

Flow field in a beadpack

Porous materials are made of an interpenetrating liquid phase dispersed in a solid or soft-solid matrix. Porous materials that are important to New Zealand's economy include food and wood products, and building materials such as concrete. Biotechnology uses porous materials in chromatography, microfiltration, drug encapsulation and delivery, tissue perfusion and dialysis applications.

Knowledge of dispersive processes in porous media is critical to oil recovery from rock and in catalysis associated with packed bed reactors. Other dispersive processes occur in ground water remediation, soil drainage, and in xylem and phloem transport in plants.

Simulated dispersion in a beadpack

Magnetic resonance can provide a signature from an imbibed liquid phase. It is extremely sensitive to translational motion (flow, diffusion, dispersion) and surface interactions, directly related to pore size distribution and permeability.

We have developed several significant new NMR modalities for making these kinds of measurements. Our current research includes:

  • measurement of velocity autocorrelation functions in space and time
  • Lattice Boltzmann simulations of dispersion
  • Laplace inversion methods to reveal diffusive and relaxation correlations.

Getting the good oil

Group member Mark Hunter presents the results of his PhD in an 8-minute presentation. Mark won the Raymond Andrew Prize for this research, developing techniques to determine the nonlocal dispersion tensor.