Structure Design Of Intelligent Rice Milling Machine And Simulation Of Rice Milling Characteristics

With the improvement in people's living standards,the development in rice processing and marketing mode is gradually leaning towards healthy nutrition.Similarly,as being an important mechanical equipment in the rice processing process,the rice mill is also constantly improving and innovating.This paper aims to develop a new intelligent rice mill that takes into account of health,safety and fresh nutrition.Further,the paper provides a comprehensive way for the rice mill market to develop intelligently and greenly.In this paper,firstly,the structure design and calculation of new type of intelligent rice milling machine are carried out.Secondly,the distribution of milling degree in different milling areas are analyzed by using the discrete element method software EDEM,and the influence of different structure forms on the milling characteristics are investigated.Finally,the process of single rice mechanical crushing is simulated by using the bonded particle model.The work and research results of this paper are as follows:(1)A design scheme of intelligent rice milling machine with high integration degree was put forward independently.First of all,the expected functions of the machine were analyzed,and were then combined with the actual mechanical design so as to determine the overall structure and layout scheme.Then the detailed structural design was developed and is described along with the calculation of key functional components.The operational parameters of the relevant components were determined as well as the type selection of the required drive motor,fan,limit switch,force sensor and other electrical components were also determined.Finally,mechanical engineering drawings were drawn and follow-ups for processing,assembly and debugging were established.The preliminary operation of the machine can achieve a more complete process from rice supply to rice output.(2)Based on the DEM numerical simulation method,the rice milling characteristics were studied.Through simulation of rice particle model and rice milling working model established in the EDEM Software,it is concluded that rice particle group has different aggregation degree and milling degree in different spatial positions of the milling chamber,“the closer to the roller,the greater the aggregation degree and milling degree”.With the increase of the distance between the region and the roller,the attenuation of milling degree is first fast and then slow.(3)The influence of different structures of milling chamber on rice milling characteristics were analyzed.By taking the shape of rice screen,the number of roller bars and the angle of roller bars as variables,the pressure and collision energy dissipation of rice grains in different axial sections were investigated,and the conclusion was drawn that “the less the number of rice screen edges is,the higher the rice milling degree is,the worse the grinding uniformity is;the more the number of roller bars is,the smaller the pressure amplitude and fluctuation are,and the more the number of roller bars is,the better the grinding uniformity,but not the grinding degree”.It is not recommended to select the right angle but if left angle is selected,the angle should not be too large,whereas,the ideal angle is 0 °.(4)In this paper,the breaking of a single rice grain under three basic forms of mechanical action of extrusion,bending and shearing was simulated by using the bonded particle model,and the damage and crack of rice were characterized by the fracture of bond.The results show that the greater stress position in the rice grain under three kinds of Mechanical action is consistent with the results of theoretical analysis,and the bonded particle model can effectively explain the process of rice from cracking to complete breaking.