| Summary: | 碩士 === 國立中央大學 === 機械工程學系 === 105 === The purpose of this research is the size segregation in the double-walled drum in different rotational speeds and wall roughness conditions. A digital video recorder was used to photograph the variation of particle migrating and concentration, and a high speed camera was used to photograph the movement process of the particles. The granular temperature of experimental results was calculated based on the pictures from the high speed camera, and the results showed the variation trend along the radial directions and angles.
The experimental results showed that the centrifugal force and gravity are the main drive forces influencing the size segregation. A special distribution state named Transition zone has been observed from the concentration changes along radial direction. Furthermore, a sandpaper was pasted on the walls of the drum, and therefore we analyzed the diversification of the particles segregation with angle and radial direction in different rough wall conditions.
The interaction of coarse particles and fine particles were observed from the results of granular temperature. The interaction zone was closed to inner wall when the centrifugal force leading the segregation mechanism. On the contrary, the interaction zone was closed to outer wall when gravity leading the segregation mechanism.
From the results of granular temperature, we have observed that the particles in the drum are given more energy with higher roughness wall, and vice versa. Hence, the transition zones of particles are moved away from the affecting wall.
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