Transportation and deposition of spherical and irregularly shaped particles flowing through a porous network into a narrow slot

In studies of the transportation and deposition of solid particles within a flow, the shape of particles has been a challenging factor to include in mathematical models. In many studies in the literature, irregularly shaped particles have been modelled essentially as perfect spheres to reduce the complexity in modelling the behavior of such particles. This paper seeks to illustrate, at the microscale, important features of particle transport that should be considered in any modelling effort. An experimental study was performed using particle shadowgraph velocimetry (PSV) in conjunction with several image processing techniques to analyze the behavior of solid particles that flow through a porous medium into a narrow slot. Three configurations were considered including the flow into a single straight slot and the flow into a slot with an inlet condition aimed to simulate porous media using cylindrical or diamond shaped pillars at different Reynolds numbers (Re = 0.1, 1 and 10) matched at the entrance of the slot. The measurement and image processing techniques used for determination of the particle rotation, particle shape, and velocity calculations are described. The velocity field was calculated and analyzed to identify the potential locations for particle deposition. While in general the characteristics of the continuous phase flow were unaffected by Re, local differences in geometry affected particle rotation and build-up as a function of particle shape. Also, particle rotation was observed in regions of irrotational flow as a function of particle position in the flow and particle shape. These results highlight that the flow geometry, particle shape and particle-fluid density difference can have a significant effect on particle rotation and deposition.