分倉儲糧對糧倉側(cè)壓力影響的離散元模擬
發(fā)布時間：2018-11-05 20:55
【摘要】：近年來,由于不同品級糧食分類收儲和質(zhì)量追溯精確化需要,對糧食存儲提出了更高的要求。目前,我國糧食儲倉倉容較大,不利于糧食的分類收儲及質(zhì)量追溯,而糧倉分倉很好的解決了這一問題。對于糧倉設(shè)計而言,側(cè)壓力是最主要的影響因素,但對于分倉下糧倉側(cè)壓力的研究還不多,因此本文主要利用PFC~(3D)離散元軟件基于糧倉單倉研究的基礎(chǔ)上研究分倉儲糧對糧倉側(cè)壓力的影響。具體研究內(nèi)容如下:(1)利用PFC~(3D)離散元軟件建立原型方倉的縮尺模型,該縮尺模型與原型方倉具有相同的重力場,保證了與原型方倉同等受力。同時確定該方倉模型的模型尺寸及細觀參數(shù)。進行方倉模型的裝料模擬,得到的倉壁靜側(cè)壓力結(jié)果與Janssen理論值相符。(2)進行方倉模型的卸料模擬,得到的倉壁動側(cè)壓力沿方倉深度的增加而增大,最大超壓系數(shù)出現(xiàn)在倉壁與漏斗交接處,并與規(guī)范、靜態(tài)模擬結(jié)果進行對比。研究表明,內(nèi)、外摩擦系數(shù)增大,方倉模型的側(cè)壓力反而減小;顆粒和墻體的剛度同時增大或減小一個數(shù)量級,方倉的動、靜側(cè)壓力相應(yīng)的增大或減小;卸料口尺寸的改變并不引起方倉模型靜側(cè)壓力的增大,卸料口尺寸增大,卸料時會減小貯料顆粒間的擠壓、碰撞,從而方倉模型的動側(cè)壓力也相應(yīng)減小。(3)通過在方倉模型內(nèi)設(shè)置隔板的方式,得到方倉模型的二分倉、四分倉模型。進行分倉模型的裝卸料模擬,得出分倉模型的靜、動側(cè)壓力隨著分倉數(shù)目的增加反而減小,隨著分倉數(shù)目的增加最大超壓系數(shù)出現(xiàn)的位置上移至漏斗以上1/3范圍內(nèi),且分倉模型的超壓系數(shù)較單倉模型小。在四分倉模型基礎(chǔ)上進行側(cè)壓力影響因素研究,得出內(nèi)、外摩擦系數(shù)增大,分倉模型的側(cè)壓力反而減小;顆粒和墻體的剛度同時增大或減小一個數(shù)量級,分倉模型的動、靜側(cè)壓力相應(yīng)的增大或減小;卸料口尺寸的改變并不引起分倉模型靜側(cè)壓力的增大,卸料口尺寸增大,卸料時會減小貯料顆粒間的擠壓、碰撞,從而分倉模型的動側(cè)壓力也相應(yīng)減小。
[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.
【學(xué)位授予單位】：河南工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：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.
【學(xué)位授予單位】：河南工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU317
【參考文獻】
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