Direct numerical simulation of particle impact on thin liquid films using a combined volume of fluid and immersed boundary method

Gas–solid flows involving wet particles are very frequently encountered in a variety of applications in industries, which includes live problems in the field of spray granulation, coking, gas phase polymerization, etc. These processes can be studied with discrete element models. The predictive capabilities of these models depend on the accuracy of the particle–particle contact dynamics. Although this dynamics is well understood for dry particles, this is not the case for wet particles. The current study focuses on a particle colliding with a thin liquid film to mimic the wet particle collisions and understand the effect of system parameters on the (apparent) restitution coefficient. Our model combines the VOF model developed by van Sint Annaland et al. (2005) and the Immersed Boundary (IB) model reported by van der Hoef et al. (2006). The Volume of Fluid (VOF) part features (i) an interface reconstruction technique based on piecewise linear interface representation (ii) a three-dimensional version of the continuum surface force (CSF) model of Brackbill et al. (1992). The Immersed Boundary (IB) part incorporates the particle–fluid interaction via a Direct Forcing Method (DFM). The hybrid VOF-IB model results are demonstrated and verified for a wide spectrum of parameters, from the experimental findings presented by Antonyuk et al. (2009).

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► Wet particle collisions are important and complex phenomenon, difficult to model.
► A non-phenomenological model with combined VOF-IB method at DNS scale is developed.
► Film thickness, impact velocity and viscosity influence effective restitution coefficient.
► Simulation results agree with previous experimental findings.
► Dissipative energy breakup for various film thicknesses is obtained.