| Bulk materials, composed by many loose, separate, different shapes of the particle, is a kind of particulate material, with a unique property and the laws of motion. Bulk materials widely exist in our real life, but the research on the performance of bulk materials is not comprehensive, the definition, classification and test methods of the bulk materials' performance are not consistent, which result in the unreasonable of the structure and type selection of the equipment used to transport and store bulk materials. All this can increase the probability of accidents and reduces the transmission efficiency in the course. Therefore, a comprehensive and accurate analysis and measurement of their different performances is very important, and it is good for the equipment design and selection of the processing, transportation and storage of bulk materials.This paper makes an intense research on the flow characteristics of bulk materials, and finds a new large scale shear test device based on the previous test methods. The main feature of the shear device is large, and it can be applied to the coal mine and other work sites for field testing, thus the obtained data can be more real. The new large scale shear test device can study the influence of the shape of the shear box on the shear test. The yield locus of bulk materials can be obtained by the shearing test. The unconstrained yield stress, effective friction angle and internal friction angle of bulk materials obtained by drawing, which can be used to measure the flow properties of bulk materials. Finally, establish a contact model of particle-particle and particle-geometry according to the principle of the discrete element method, and calibrate the energy density, coefficient of static friction, and the coefficient of rolling friction of the JKR modle in the simulation of EDEM by conducting a virtual experiment, and then the flow properties of different moisture content, different particle shape and different size distribution are carried out. Taking the delivery state of the bulk materials on the belt conveyor as an example, the simulation result shows that:(1) The fuller the particle shape, which is closer to the ball, the greater the output speed, so as the flow properties;(2) Under the premise of consistent particle shape, fine particles can affect the flow properties of bulk materials;(3) The flow properties of the bulk materials will decrease with the increasing moisture content in a specific range. The simulation results of this paper provide a reference for how the three factors affect the flow properties of bulk materials.The performance of this paper provides a reference value for the rational design and processing, transport and storage of bulk materials device. The development of new shear device and the simulation data of EDEM have a great influence on the selection of belt conveyor. Using the flow properties of bulk materials to estimate the stacking cross section and the sprinkle materials situation on the conveyor belt can provide a selection of an appropriate type of belt conveyor, which will reduce unpredictable damages and avoid time wasting, financial expenditure and material expense. |
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