Hydrodynamic dispersion in open cell polymer foam

Nuclear magnetic resonance experiments and pore-scale lattice-Boltzmann simulation in conjunction with random-walk particle-tracking are used to probe molecular displacement statistics over a range of time and lengths within several open-cell polymer foams. Short-time molecular displacement dynamics of a flowing liquid within these structures are shown to reveal a well-defined characteristic transport length scale. The non-equilibrium statistical mechanics theory of dispersion is used to interpret the unique displacement dynamics. Scaling of data from experiment, simulation, and the non-equilibrium statistical mechanics model by the transport length scale collapses the dynamics to dimensionless scaling. Asymptotic dispersion dynamics from NMR experiment are presented as function of Peclet number defined using the transport length scale.