https://scholars.lib.ntu.edu.tw/handle/123456789/598829
標題: | Continuum simulation of non-local effects in a granular silo discharge flow using a regularized μ (I) rheology model | 作者: | Lin C.-C Yang F.-L. FU-LING YANG |
關鍵字: | Aspect ratio;Elasticity;Fluidization;Missile silos;Momentum;Momentum transfer;Shear strain;Velocity;Continuum simulations;Discharge flow;High shear;Local flows;Momentum transports;Non-local effect;Nonlocal;Nonuniform field;Shear zone;Silo discharge;Orifices | 公開日期: | 2021 | 卷: | 33 | 期: | 9 | 來源出版物: | Physics of Fluids | 摘要: | The effect of non-local momentum transport on a silo discharge process is numerically investigated using a continuum simulation with the μ (I) rheology model in which the gradient expansion model is adopted to account for the non-local effects due to the non-uniform field of inertial number I [Bouzid et al., Phys. Rev. Lett. 111, 238301 (2013)]. The singularity for I = 0 is handled with a regularization scheme [Lin and Yang, J. Comput. Phys. 420, 109708 (2020)]. Compared to the discharge dynamics predicted with the local μ (I) rheology model, the non-local effect enhances the velocity field to increase the volume discharge flow rate Q, especially when the silo orifice L is narrower. Both the local and non-local flow simulations conform to the Beverloo relation Q = C ρ g (L - k d) 3 / 2, where d is the intrinsic grain diameter but the non-local effects appear to lessen the orifice reduction effect coefficient k. The difference between the local and the non-local flow rates Δ Q ¯, made dimensionless by ρ g d 3 / 2, grew monotonically with decreasing L/d with a slight enhancement if the silo height-to-width aspect ratio deviates from unity. Finally, we evaluated the ratio of the shear strain rate to the instantaneous maximum value to define a high-shear zone when the ratio is above a threshold and studied its evolution from the onset to the end of the discharge process. Interestingly, non-local momentum transport helped to reduce the size of the high-shear zone to give a more uniformly fluidized central zone above the orifice. ? 2021 Author(s). |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-85115312239&doi=10.1063%2f5.0057598&partnerID=40&md5=2e66b4733c4d880ff204691da851e07b https://scholars.lib.ntu.edu.tw/handle/123456789/598829 |
ISSN: | 10706631 | DOI: | 10.1063/5.0057598 |
顯示於: | 機械工程學系 |
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