筒壁卸料动态侧压力试验研究

发布时间：2018-09-10 19:35

【摘要】：筒仓的动态压力大于静态压力已是不争的事实,但引起动态压力增大的原因复杂,长期以来一直处于探索阶段。到目前为止,尚没有成熟的设计理论。尤其是筒壁卸料理论更加匮乏。因此,研究筒壁卸料过程中物料流动对仓壁侧压力具有重要的理论意义和实用价值。论文依托国家自然科学基金项目:《基于装卸料过程能量转换的筒仓动态超压机理研究》(项目编号:51578216)。本文主要内容有:(1)结合工程实例,制作筒仓模型,对土压力传感器进行标定,布置在设定位置的筒仓内壁上。(2)采用单侧和双侧两种卸料方式对高径比不同(1.1和2.2)的筒仓进行静态压力和动态压力测试。使用土压力传感器,测试最大贮料高度各测点静态压力值,并与理论值对比分析;测试卸料过程中的动态侧压力;根据试验结果计算超压系数,分析最大超压系数发生位置。(3)结果表明,筒壁单侧卸料过程中,浅仓最大超压系数发生位置在0.2m深度处,值为1.57;深仓最大超压系数发生位置在0.4m深度处,值为1.74。筒壁双侧卸料过程中,浅仓最大超压系数在0.2m处,值为1.51;深仓最大超压系数在0.4m深度处,值为1.58。由此可知,浅仓最大超压系数比深仓小,单侧卸料的超压系数比双侧卸料大。(4)对仓内物料流态进行研究,并利用PFC3D颗粒流程序建立与试验使用的深仓筒壁双侧卸料筒仓相同的模型,将模拟流态与拍摄所得的流态对比分析。结果表明,模拟流态与试验拍摄所得流态基本吻合。其中高径比为1.1的筒仓,卸料过程中发生管状流动,仓内存在明显的静止和流动区域,且流动区域与静止区域截面不和仓壁相交;高径比为2.2的筒仓,卸料过程中发生混合流动,区域主要分布在0.3m-0.5m左右深度处,进而导致筒仓上部为整体流动,下部为管状流动。
[Abstract]:It is an indisputable fact that the dynamic pressure of silo is greater than the static pressure, but the reasons for the increase of the dynamic pressure are complicated and have been in the stage of exploration for a long time. So far, there is no mature design theory. Especially the theory of cylinder wall discharge is more scarce. Therefore, it is of great theoretical significance and practical value to study the material flow in the discharge process of cylinder wall. This paper relies on the National Natural Science Foundation of China: research on dynamic overpressure Mechanism of Silo based on Energy conversion in loading and unloading process (item No.: 51578216). The main contents of this paper are as follows: (1) combined with engineering examples, the silo model is made and the earth pressure sensor is calibrated. (2) the static pressure and dynamic pressure of silo with different ratio of height to diameter (1.1 and 2.2) were measured by two discharge methods: one side and two sides. Using the earth pressure sensor, the static pressure values at each measuring point of the maximum storage height are measured and compared with the theoretical values; the dynamic lateral pressure during discharge is tested; the overpressure coefficient is calculated according to the test results. The results show that the maximum overpressure coefficient of shallow silo occurs at the depth of 0.2m with a value of 1.57, and the maximum overpressure coefficient of deep warehouse occurs at the depth of 0.4 m, with a value of 1.74. The maximum overpressure coefficient of shallow silo is 0.2m and the maximum overpressure coefficient of deep silo is 1.58m in the depth of 0.4m. It can be seen that the maximum overpressure coefficient of shallow silo is smaller than that of deep bin, and the overpressure coefficient of discharging material on one side is larger than that of both sides. (4) the material flow pattern in warehouse is studied. Using PFC3D particle flow program to establish the same model as the double-side unloading silo used in the experiment, and to compare the simulated flow state with the flow state obtained by shooting. The results show that the simulated flow pattern is in good agreement with the experimental one. In silo with aspect ratio 1.1, tubular flow occurs during discharge, and there are obvious static and flowing areas in the silo, and the flow area does not intersect with the wall of the silo in the static area, while the silo with a ratio of height to diameter of 2.2. The mixed flow occurs in the unloading process, and the region is mainly distributed at the depth of the 0.3m-0.5m, which leads to the overall flow in the upper part of the silo and the tubular flow in the lower part of the silo.
【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】：TU375

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