圆锥料仓内颗粒周期性脉动特征研究

发布时间：2018-02-02 21:53

本文关键词： 料仓卸料颗粒脉动接触力　出处：《物理学报》2017年01期 　论文类型：期刊论文

【摘要】：料仓卸料过程中的颗粒脉动会引起料仓振动甚至导致结构失效.为了明晰颗粒脉动特征,本文进行了椭球颗粒在不同半锥角深仓的模拟卸料实验,将料仓圆筒部划分为4个固定区域以研究区域内颗粒的运动信息,分析了料仓圆筒部颗粒系统的运动特征.研究结果表明:整个卸料过程颗粒速度始终处于波动变化中,卸料前期表现为大振幅、周期性的剧烈脉动,卸料后期平均速度的变化则是小振幅无规律的波动;剧烈脉动时段各区域的颗粒层平均受力的变化规律与颗粒速度脉动特征相似,越接近储料顶端颗粒脉动振幅越大,表现出更规律的周期性脉动,相邻颗粒层间的脉动波形相似且周期相同,剧烈脉动过程中顶面颗粒呈周期性的自由落体运动,该时段内顶层颗粒每一次的自由落体运动都会引起该范围内颗粒间接触力消失;料仓半锥角越小时剧烈脉动频率越高、振幅越大且脉动持续时间也越长,卸料速度越稳定,且颗粒速度不会出现带有上升趋势的波动.研究结果可为卸料设备的安全设计提供参考.
[Abstract]:Particle pulsation in the unloading process can cause silo vibration and even lead to structural failure. In order to understand the characteristics of particle pulsation, a simulated discharge experiment of ellipsoidal particles in different semi-conical deep silo is carried out in this paper. The silo cylinder is divided into four fixed regions to study the movement information of particles in the region. The characteristics of the particle system in the silo cylinder are analyzed. The results show that the particle velocity is always fluctuating in the whole unloading process, and the early unloading stage is characterized by large amplitude and periodic sharp pulsation. The variation of average velocity at the later stage of discharge is irregular fluctuation of small amplitude. The variation law of the average force of particle layer in each region during the period of intense pulsation is similar to the characteristic of particle velocity pulsation. The closer the particle pulsation amplitude is to the top of material storage, the larger the amplitude of particle pulsation is, which shows more regular periodic fluctuation. The pulsation waveforms of adjacent particle layers are similar and the period is the same, and the particles on the top surface show periodic free falling motion in the process of intense pulsation. Every free falling movement of the top layer particles in this time period will cause the contact force between particles to disappear in this range. The smaller the semi-cone angle of the silo, the higher the frequency of intense pulsation, the larger the amplitude and the longer the duration of pulsation, and the more stable the unloading speed is. The particle velocity does not fluctuate with an upward trend. The results of the study can provide a reference for the safe design of unloading equipment.
【作者单位】：东北农业大学工程学院;
【基金】：国家自然科学基金(批准号:51575098) 黑龙江省自然科学基金(批准号:E201322) 哈尔滨市优秀学科带头人基金(批准号:RC2013XK006004)资助的课题~~
【分类号】：O347.7
【正文快照】： 1引言颗粒物质是由大量单体颗粒相互作用而形成的复杂系统[1],往往表现出类固-类液的运动特性[2],常被视作除固、液、气之外的第四态物质,激起了国内外研究者的广泛关注.颗粒物质的密集流动[3]、二元混合[4]、堆积[5]、结拱堵塞[6]等更是研究的热点和难点.在食品工程、农业

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