摘要(英) |
The purpose of the study is to investigate the flow behaviour of spherical and non-spherical particles in vibrating beds, to compare the transport properties between them, and to explore the influence of particle shape on the flow behavior and transport properties. This study also shows the variations of flow behavior on vibrational conditions (dimensionless vibrational acceleration and vibrational frequency). The granular materials used in vibrating tests were ABS particles including spherical, ellipsoidal I (aspect ratio=1.5), ellipsoidal II (aspect ratio=2.0), capsule (aspect ratio=2.0) and paired particle (aspect ratio=2.0). The Improved Particle Tracking Velocimetry (PTV) was employed to measure the translational and rotational velocities of the non-spherical particles. The transport properties of the particles in a vibrated bed, including translational velocity vector, rotational velocity vector, granular temperatures, translational kinetic energy, rotational kinetic energy, self-diffusion coefficients and fluctuation velocity distributions were analyzed. The experimental results reveal that the degree of the inter-locking effect follows the sequence: paired particle > capsule particle > ellipsoidal II particle. It is pointed out that the diffusion coefficient can be used as an index to represent the inter-locking effect. In the same vibrational frequency, the velocity vector, granular temperatures, translational kinetic energy, rotational kinetic energy and self-diffusion coefficients of the particles increase with dimensionless vibrational acceleration. In the same dimensionless vibrational acceleration, the corresponding transport properties increase with the decrease of the vibrational frequency. Both are attributed to the increasing amplitude, providing more energy for granular assembly especially for the latter. This is that the amplitude is inversely proportional to the square of the vibrational frequency, and is linearly proportional to the dimensionless vibrational acceleration. |
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