Demixing in turbulent 3 phase flows

We investigate how solid particles adhere to the surfaces of the bubbles, or get entrapped in the wakes of the bubbles, both leading to net upward transport of the particles. More specific to the first mechanism, the main questions that we address can be summarised as follows: ·         How does turbulence influence the adhesion of the particles, i.e. does turbulence indirectly influence the film drainage process, and if so, how?·         How does turbulence influence the entrainment of particles from the bubble surface, i.e. does the turbulence in the flow around the bubble cause a re-entrainment of particles from the interface back into the fluid?·         How does the turbulence influence the formation and the stability of a stagnant cap of particles at the lower end of the bubble?·         A related question is on wetting properties of the particles. How does this affect the effectiveness of the flotation process? Also, in practice the shape of the particles determines the wetting properties (i.e., the particles, especially crystals, are not always spherical, but can form a ‘spiky’ surface, in the form of ‘flakes’, ‘needles’ or ‘dendrites’). More specific to the second mechanism, the main questions that we address can be summarised as follows: ·         How does the relative density of particles affect the change in concentration in the wake of a bubble ·         Can the (turbulent) fluxes of particles through the closing streamline of the wake be measured directly through two-phase Particle Image Velocimetry? The project as a whole could lead to an engineering model for particle transport that can be used directly in commercial large-scale simulation packages.