高级检索

气压对颗粒物质振动分离的影响

Effects of air on the segregation of particles in a shaken granular bed

  • 摘要: 文章作者系统地研究了垂直振动颗粒床中,在不同气压、颗粒尺寸以及密度情况下大球的运动规律.实验发现,系统处于真空状态或低气压时,大球总是向上运动.然而,当在通常大气压下,大球则会出现上升和下降两种运动状态.大球下降这种运动状态,只在大球的密度和颗粒床中颗粒尺寸足够小时才会出现,颗粒床中的负气压梯度导致大球下降.

     

    Abstract: The effects of interstitial air on the motions of a large intruder in a shaken granular bed are studied experimentally as a function of ambient air pressure, particle size of the bed, and the density of the intruder. It is found that the intruder always rises from the granular bed in the absence of air. However, the intruder can acquire both positive and negative buoyancy in the presence of air. Negative buoyancy can be observed only when both the density of the intruder and the particle size of the bed are small enough. This negative buoyancy can be explained by the unusual air pressure distribution found in the bed.

     

/

返回文章
返回