A new blended acceleration model for the particle contact forces induced by an interstitial fluid in dense particle/fluid flows

Abstract We use the Multi-Phase Particle-in-Cell (MP-PIC) numerical method to simulate binary fluidized beds and find that experimentally measured separation of the two particle types in such beds can be explained by including a new contact force model in MP-PIC that accounts for the inhibition of relative motion between particles of differing sizes or densities. Without the new contact force model, we find that there is poor agreement between experimentally measured and MP-PIC calculated particle separation. In the new contact force model, individual particle accelerations are a blend between the particle acceleration of the original MP-PIC method, appropriate for rapid granular flows, and an average particle acceleration that applies to closely packed granular flows, and we call the new model the “blended acceleration” model. In this paper, we develop the equations of the blended acceleration model, detail its numerical implementation, verify correct implementation by comparing with an analytic solution for one-dimensional binary beds, and compare MP-PIC calculation results with three sets of measurements of particle separation in binary beds.

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