分仓储粮对粮仓侧压力影响的离散元模拟
发布时间：2018-11-05 20:55
【摘要】：近年来,由于不同品级粮食分类收储和质量追溯精确化需要,对粮食存储提出了更高的要求。目前,我国粮食储仓仓容较大,不利于粮食的分类收储及质量追溯,而粮仓分仓很好的解决了这一问题。对于粮仓设计而言,侧压力是最主要的影响因素,但对于分仓下粮仓侧压力的研究还不多,因此本文主要利用PFC~(3D)离散元软件基于粮仓单仓研究的基础上研究分仓储粮对粮仓侧压力的影响。具体研究内容如下:(1)利用PFC~(3D)离散元软件建立原型方仓的缩尺模型,该缩尺模型与原型方仓具有相同的重力场,保证了与原型方仓同等受力。同时确定该方仓模型的模型尺寸及细观参数。进行方仓模型的装料模拟,得到的仓壁静侧压力结果与Janssen理论值相符。(2)进行方仓模型的卸料模拟,得到的仓壁动侧压力沿方仓深度的增加而增大,最大超压系数出现在仓壁与漏斗交接处,并与规范、静态模拟结果进行对比。研究表明,内、外摩擦系数增大,方仓模型的侧压力反而减小;颗粒和墙体的刚度同时增大或减小一个数量级,方仓的动、静侧压力相应的增大或减小;卸料口尺寸的改变并不引起方仓模型静侧压力的增大,卸料口尺寸增大,卸料时会减小贮料颗粒间的挤压、碰撞,从而方仓模型的动侧压力也相应减小。(3)通过在方仓模型内设置隔板的方式,得到方仓模型的二分仓、四分仓模型。进行分仓模型的装卸料模拟,得出分仓模型的静、动侧压力随着分仓数目的增加反而减小,随着分仓数目的增加最大超压系数出现的位置上移至漏斗以上1/3范围内,且分仓模型的超压系数较单仓模型小。在四分仓模型基础上进行侧压力影响因素研究,得出内、外摩擦系数增大,分仓模型的侧压力反而减小;颗粒和墙体的刚度同时增大或减小一个数量级,分仓模型的动、静侧压力相应的增大或减小;卸料口尺寸的改变并不引起分仓模型静侧压力的增大,卸料口尺寸增大,卸料时会减小贮料颗粒间的挤压、碰撞,从而分仓模型的动侧压力也相应减小。
[Abstract]:In recent years, due to the need of classification and storage of grain of different grades and precision of quality traceability, higher requirements have been put forward for grain storage. At present, the storage capacity of grain storage warehouse in China is large, which is not conducive to the classification of grain storage and quality traceability, but the grain warehouse sub-warehouse is a good solution to this problem. For granary design, lateral pressure is the most important factor, but there is not much research on silo lateral pressure under granary. In this paper, we mainly use PFC~ (3D) discrete element software to study the effect of grain distribution on the lateral pressure of grain warehouse based on the single warehouse research. The main contents are as follows: (1) PFC~ (3D) discrete element software is used to establish the scale model of the prototype square bin, which has the same gravity field as the prototype square bin, which ensures the same force as the prototype square bin. At the same time, the model size and mesoscopic parameters are determined. The static lateral pressure of the silo wall is in agreement with the Janssen theory. (2) the dynamic lateral pressure of the silo wall increases with the increase of the depth of the silo, and the unloading simulation of the silo model is carried out, and the dynamic lateral pressure of the silo wall increases with the increase of the depth of the silo. The maximum overpressure coefficient appears at the junction of the silo wall and the funnel and is compared with the results of the specification and static simulation. The results show that the lateral pressure decreases with the increase of internal and external friction coefficient, and the stiffness of grain and wall increases or decreases by one order of magnitude at the same time, and the dynamic and static lateral pressure increases or decreases accordingly. The change of discharge port size does not cause the increase of static lateral pressure in the square bin model, and the size of discharge port increases, and the extrusion and collision between the storage particles will be reduced when discharging. As a result, the dynamic lateral pressure of the square warehouse model is reduced accordingly. (3) by setting a partition in the square warehouse model, the second and fourth warehouse models of the square warehouse model are obtained. Through the loading and unloading simulation of the separation model, it is concluded that the static and dynamic lateral pressure decreases with the increase of the number of the bunker, and the position of the maximum overpressure coefficient is moved up to the range of 1 / 3 above the funnel with the increase of the number of the bunker. The overpressure coefficient of the partition model is smaller than that of the single warehouse model. On the basis of the silos model, the influence factors of the lateral pressure are studied. The results show that the internal and external friction coefficient increase, but the lateral pressure of the silos model decreases. The stiffness of grain and wall increases or decreases by an order of magnitude at the same time, and the dynamic and static lateral pressure of the silo model increases or decreases accordingly. The change of discharging port size does not cause the increase of static lateral pressure of the separation model, and the size of discharge port increases, and the extrusion and collision between the storage particles will be reduced when unloading, thus the dynamic lateral pressure of the separation model will be reduced accordingly.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU317
[Abstract]:In recent years, due to the need of classification and storage of grain of different grades and precision of quality traceability, higher requirements have been put forward for grain storage. At present, the storage capacity of grain storage warehouse in China is large, which is not conducive to the classification of grain storage and quality traceability, but the grain warehouse sub-warehouse is a good solution to this problem. For granary design, lateral pressure is the most important factor, but there is not much research on silo lateral pressure under granary. In this paper, we mainly use PFC~ (3D) discrete element software to study the effect of grain distribution on the lateral pressure of grain warehouse based on the single warehouse research. The main contents are as follows: (1) PFC~ (3D) discrete element software is used to establish the scale model of the prototype square bin, which has the same gravity field as the prototype square bin, which ensures the same force as the prototype square bin. At the same time, the model size and mesoscopic parameters are determined. The static lateral pressure of the silo wall is in agreement with the Janssen theory. (2) the dynamic lateral pressure of the silo wall increases with the increase of the depth of the silo, and the unloading simulation of the silo model is carried out, and the dynamic lateral pressure of the silo wall increases with the increase of the depth of the silo. The maximum overpressure coefficient appears at the junction of the silo wall and the funnel and is compared with the results of the specification and static simulation. The results show that the lateral pressure decreases with the increase of internal and external friction coefficient, and the stiffness of grain and wall increases or decreases by one order of magnitude at the same time, and the dynamic and static lateral pressure increases or decreases accordingly. The change of discharge port size does not cause the increase of static lateral pressure in the square bin model, and the size of discharge port increases, and the extrusion and collision between the storage particles will be reduced when discharging. As a result, the dynamic lateral pressure of the square warehouse model is reduced accordingly. (3) by setting a partition in the square warehouse model, the second and fourth warehouse models of the square warehouse model are obtained. Through the loading and unloading simulation of the separation model, it is concluded that the static and dynamic lateral pressure decreases with the increase of the number of the bunker, and the position of the maximum overpressure coefficient is moved up to the range of 1 / 3 above the funnel with the increase of the number of the bunker. The overpressure coefficient of the partition model is smaller than that of the single warehouse model. On the basis of the silos model, the influence factors of the lateral pressure are studied. The results show that the internal and external friction coefficient increase, but the lateral pressure of the silos model decreases. The stiffness of grain and wall increases or decreases by an order of magnitude at the same time, and the dynamic and static lateral pressure of the silo model increases or decreases accordingly. The change of discharging port size does not cause the increase of static lateral pressure of the separation model, and the size of discharge port increases, and the extrusion and collision between the storage particles will be reduced when unloading, thus the dynamic lateral pressure of the separation model will be reduced accordingly.
【学位授予单位】：河南工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU317
【参考文献】
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