CFD simulation for secondary breakup of coal–water slurry drops using OpenFOAM

• CFD simulation of single coal water slurry drop in secondary breakup
• Breakup of non-Newtonian drops with high density ratios in turbulent flow
• Using of Laplacian filter function and dynamic mesh to reduce the parasitic currents
• Finding an effective constant viscosity for an analogous Newtonian breakup regime

The main objective of this study is to gain insight into dynamic behavior of coal–water slurry (CWS) drops during secondary breakup. In the case of Bingham liquids (CWS) considered here, this endeavor requires a thorough understanding of the influence of the shear-thinning and viscoplastic fluid rheology on the flow inside the deforming drops. In numerical analysis, a coupled technique including Large Eddy Simulation (LES) and smoothed volume of fluid (VOF) was used with a dynamic adaptive mesh. The effects of variations in secondary breakup and viscoplastic liquid rheological parameters on Sauter mean diameter (SMD), droplet aspect ratio, and dynamic average viscosity were studied in detail. The results show good predictions for the breakup regimes. Moreover, an effective constant viscosity leading to a similar Newtonian breakup regime was detected in all cases. According to the analogy between secondary and primary breakups, the results can be used to better understand the CWS jet breakup.

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