Flow Theoretical Study And Numerical Simulation Of Bulk Material

Bulk material is refers to a large number of massive, granular or powder.Bulk material can be widely found in all areas of production and life,particularly in the field of energy, mining, food,chemical, metallurgy and building materials.The common bulk materials are ore, coal, grain and so on.The flowability of bulk material plays a very important role in the design and optimization process of the storage and transportation machinery and equipment,therefore,it has a practical significance to research the flowability of bulk material.The flowability of bulk material was studied in this paper.Based on the research of the parameters and the measurement methods to represent the flowability of bulk material,the shear principle,measurement process and the calculation of the parameters of the Jenike shear tester were main studied in this paper.The main contents are as follows:(1) Analysis the influencing mechanism of the main factors to the flowability of bulk material such as the particle size, particle size distribution,humidity and particle shape.Use fractal dimension theory to study the particle size distribution of bulk material.By the method of screening experiments,calculate the fractal dimension of the corn samples in this paper,and we get the value of the fractal dimension is 2.13,which indicating that the sample material in larger particles content is relatively high.At the same time,the experimental data of the size distribution of the sample provides the basis for the subsequent simulation experiment.(2) Designed a reasonable experimental equipment of the angle of repose measurement.After a number of the angle of repose experiments were carried out and the analysis of the experimental date,we got the angle of repose of the corn sample which was 25°.Using three-dimensional modeling software Pro /E,a geometry with the same geometrical parameters was established and imported into the discrete element software EDEM to accomplish the parametercalibration experiment,which can get the same physical parameters with the corn sample.And the data obtained in the subsequent shear simulation experiment has practical significance,and can be used for the Jenike flow experiment of the sample.(3)The discrete element software EDEM was used to simulate the shear process of bulk materials, and different pressure was applied to the sample material during the shearing process, and the shear stress curves of the samples were obtained under different pressure.After analyzing the shear force curve,.it was found that when the pressure imposed on the sample was 1000 N,would appear the phenomenon of overcompaction.so we can get the conclusion that in the actual Jenike flow experiment, the precompaction force should not be more than 1000 N.Through this method can replace a certain amount of experimental in the Jenike flow experiments which are needed to measure the reasonable range of precompaction of the shear test, and reduce the waste of the workload and materials.