Tangential viscous force models for pendular liquid bridge of Newtonian fluid between moving particles

•Tangential viscous force models for pendular liquid bridge are proposed.•The proposed models show improvements compared to other models in literature.•Explicit relationship between the bridge volume and bridge radius is derived.

In wet powder handling processes, it is of paramount importance to accurately estimate the viscous force acting on particles. In the present work, the tangential viscous force models for a pendular liquid bridge used in Discrete Element Method (DEM) in literature are reviewed first, and then new models are proposed by modifying the Xu model (Xu et al., 2005) based on the numerical solution of the pressure equation derived from the lubrication theory. The results obtained from the proposed models are compared with those from Direct Numerical Simulation (DNS) to find that they show good agreement with each other when the separation distance is sufficiently small, i.e. when the lubrication approximation is valid. The validity and accuracy of the models in literature are also discussed.

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