| Granular matter refers to a discrete system composed of a large number of particles,which is closely related to human production and life,such as grain production,mineral sorting,medical tablets and snow flakes.Therefore,the research on granular matter has great engineering application value.Since the discovery of the "Brazil Nut Separation" phenomenon,many scholars and engineers have conducted in-depth research on the mechanism of particle separation.However,due to the complexity of the particle system,there is no exact explanation so far.Only a variety of mechanisms compete with each other,mainly for void filling and convection mechanism.There are also penetration,condensation,thermal diffusion,air gap,inertia,etc.As a result,the study of granular matter also has great academic value.The particles of grain in agriculture can be regarded as a special shape of granular matter.The process of grain separation can also be regarded as the process of particle separation under vibration.In order to realize the separation of paddy rice and stalks in V-trough and reveal its separation mechanism,geometry model of V-trough is established by Solid Works software Firstly.Using EDEM software to establish particle model of paddy rice and stalk.Then the movement behavior of paddy rice and stalk under horizontal vibration is simulated and the separation mechanism of them can be obtained.The influences of parameters on the effect of paddy rice and stalk separation are discussed,including V-trough shape,V-trough vibration frequencies(4～7 Hz)and amplitudes(10～25 mm),V-trough initial inclination angle(-10 °～15 °)and excitation mode(vertical vibration and pendular oscillation).The most suitable parameters for separation of paddy rice and stalk can be obtained.Finally a validation test to verify the accuracy of the simulation results.The results show that: the V-trough with a frequency of 6 Hz and an amplitude of20 mm can separate the paddy rice and stalk,but the separation configuration is flawed.Using the kinetic energy theorem,combined with related theories of theoretical mechanics and fluid mechanics,the separation mechanism of paddy rice and stalk in V-trough can be explained.In the process of discussing the parameters affecting the separation effect of paddy rice and stalk,it can be found that the addition of transverse ribs at the bottom and arc wall of the V-trough can greatly enhance the separation effect of paddy rice and stalk,and the final obtained paddy rice volume concentration is 1.During the discussion of the frequency and amplitude of the V-trough,it can be found that different combinations of frequency and amplitude canachieve complete separation of paddy rice and stalk.During the discussion of the initial inclination angle of the V-trough,it can be found that the negative inclination angle is not conducive to the separation of paddy rice and stalk.The positive inclination angle has little effect on the separation effect of paddy rice and stalk,but has a great influence on the separation configuration.During the discussion of the vibration mode of the V-trough,it can be found that paddy rice and stalk can not separate under vertical vibration,and they have a tendency to separate under pendular oscillation,but can not be completely separated.The final validation test demonstrates the effectiveness of the discrete element method.Through the study on the separation behavior of paddy rice and stalk in V-trough,the mechanism of particle separation is revealed,which provides some theoretical support for the research and improvement of granular matter dynamics.At the same time,the experimental platform designed and constructed during the research process can provide new processes and equipment for grain separation,which has a positive effect on promoting the development of agricultural mechanization. |
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