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Flow behaviors of four kinds of granular particles(i.e. sphere,ellipsoid,hexahedron and binary mixture of sphere and hexahedron) in rectangular hoppers were experimentally studied. The effects of granular shape and hopper structure on flow pattern,discharge fraction,mean particle residence time and tracer concentration distribu-tion were tested based on the visual observation and particle tracer technique. The results show that particle shape affects significantly the flow pattern. The flow patterns of sphere,ellipsoid and binary mixture are all parabolic shape,and the flow pattern shows no significant difference with the change of wedge angle. The flowing zone be-comes more sharp-angled with the increasing outlet size. The flow pattern of hexahedron is featured with straight lines. The discharge rates are in increasing order from hexahedron,sphere,binary mixture to ellipsoid. The dis-charge rate also increases with the wedge angle and outlet size. The mean particle residence time becomes shorter when the outlet size increases. The difference of mean particle residence time between the maximum and minimum values decreases as the wedge angle increases. The residence time of hexahedron is the shortest. The tracer concen-tration distribution of hexahedron at any height is more uniform than that of binary mixture. The tracer concentra-tion of sphere in the middle is lower than that near the wall,and the contrary tendency is found for ellipsoid particles.
Flow behaviors of four kinds of granular particles (ie sphere, ellipsoid, hexahedron and binary mixture of sphere and hexahedron) in rectangular hoppers were experimentally studied. The effects of granular shape and hopper structure on flow pattern, discharge fraction, mean particle residence time and tracer concentration distribu- tion were tested based on the visual observation and particle tracer technique. The results show that particle shape scenarios significantly the flow pattern. The flow patterns of sphere, ellipsoid and binary mixture are all parabolic shape, and the flow pattern shows no significant difference with the change of wedge angle. The flowing zone be-came more sharp-angled with the increasing outlet size. The flow pattern of hexahedron is featured with straight lines. The discharge rates are in increasing order from hexahedron, sphere, binary mixture to ellipsoid. The dis-charge rate also increases with the wedge angle and outlet size. The mean particle residence time beco The shorter of the outlet size increases. The difference of mean particle residence time between the maximum and minimum values decreases as the wedge angle increases. The residence time of hexahedron is the shortest. The tracer concen- tration distribution of hexahedron at any height is more uniform than that of binary mixture. The tracer concentra- tion of sphere in the middle is lower than that near the wall, and the contrary tendency is found for ellipsoid particles.