CAJ | 학술논문

颗粒物质流经瓶颈时难以预知的堵塞现象是1个古老且令人困惑的难题.本文选取3种球形颗粒,统计分析颗粒流出小于临界开口尺寸锥形瓶颈的颗粒数,探讨堵塞转变的概率分布特征和物理机制.结果显示:(1)堵塞前流出瓶颈的颗粒数概率分布存在1个峰值,峰值前概率呈幂函数增长,峰值后概率为指数衰减;(2)颗粒的密度、弹性系数及表面摩擦等因素影响颗粒间的接触时间、堵塞结构稳定性和堵塞概率分布.当瓶颈开口尺寸低于临界尺寸,且颗粒流态由稀疏流转变为密集流后,堵塞转变必将发生.
과립물질류경병경시난이예지적도새현상시1개고로차령인곤혹적난제.본문선취3충구형과립,통계분석과립류출소우림계개구척촌추형병경적과립수,탐토도새전변적개솔분포특정화물리궤제.결과현시:(1)도새전류출병경적과립수개솔분포존재1개봉치,봉치전개솔정멱함수증장,봉치후개솔위지수쇠감;(2)과립적밀도、탄성계수급표면마찰등인소영향과립간적접촉시간、도새결구은정성화도새개솔분포.당병경개구척촌저우림계척촌,차과립류태유희소류전변위밀집류후,도새전변필장발생.
Jamming of granular matter in a bottleneck flow occurs widespread without predicting,which is an ancient and confusing question. In the present work, the number of the grains discharged from the cone-shaped bottleneck below critical size before jamming was measured statistically; the characteristics of probability distribution and the physical mechanism of jamming with three kinds of spherical grains were explored. The results show: (1) The probability distribution of the number of discharging grains before jamming shows a peak;a power law growth to the left, and an exponential tail to the right;(2) The density, coefficient of elasticity and the surface friction of the spherical grains have effects on the contact time between grains, the stability of jamming configuration and probability distribution of jamming size. If the bottleneck size is below critical size and the dilute flow shift into dense flow, jamming will inevitably occur.