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• Main Authors: Chao-Wang Wu, 吳朝旺
• Other Authors: 鍾雲吉
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/78458936264232756249

碩士 === 國立中央大學 === 機械工程學系 === 105 === The aim of the study is to investigate the flow behavior of spherical particles in an inclined chute with a cylindrical obstacle by using PIV measurement technique and discrete element modelling. The proposed DEM model is first validated against the corresponding experiment. After reasonable justification, the DEM results are further employed to explore the transport and internal properties of granular flow driven by gravity in the inclined chute. The physical properties, including flow depth, solid fraction, velocity profile, angular velocity, granular temperature, coordination number, stress state, contact force orientation and fabric tensor, are evaluated. In addition, the effect of the obstacle and friction on physical properties is also examined. The particles adjacent to the side walls exhibit smaller translational velocity in the streamwise direction, but larger angular velocity and in-plane shear stresses due to boundary friction effect. This boundary friction also leads to granular dilatancy, which makes solid fraction, coordination number, normal stress and out-of-plane shear stresses decrease. The granular flow shows higher granular temperature at the place where particles fly in the air and fall onto the inclined chute again. In addition, the granular temperature near the boundary (sidewalls and bottom wall) and at the free surface is larger than that in the central part. Due to the obstacle, the granular jamming forms and results in an increase of coordination number, normal and shear stresses. The contact force orientation become more streamwise as a result of granular deposit, but scatters when the particles fly in the air. After the particles fall onto the inclined chute again, the contact force orientation becomes steeper.