Arrangement And Structure Optimization Of Key Components In Concrete Distributor Based On DEM

With the rise of prefabricated buildings,spiral concrete spreader is widely used in production enterprises because of its wide application range of concrete fluidity,accurate control of discharge quantity,convenient for numerical control production and many other advantages.As the key parts of the distributor,the spiral and discharge channel have many problems in the actual production,such as the random arrangement of the spiral and the various shapes of the discharge channel,etc.,which lead to the uneven discharge of the distributor,the large difference of the spiral wear,the low specific power consumption,and then lead to the low strength of the prefabricated components,the need for human intervention in production,and the increase of production cost.The spiral of concrete spreader has a vital influence on the quality and state of output concrete.Therefore,based on the discrete element method,this paper establishes the multi helix concrete distributor model,and based on the fluidity experiment of fresh concrete,demarcates the concrete DEM model parameters.At the same time,the effects of four kinds of spiral arrangement and three kinds of discharge channel shapes on the movement of material particles,the uniformity of discharge and the specific power consumption in the multi spiral concrete distributor are studied,which is of great significance to improve the working performance and economic benefits of the multi spiral concrete distributor.Based on the investigation of the spiral concrete distributor in the market and the experimental devices at home and abroad,a four spiral concrete distributor experimental device is designed and manufactured by ourselves.The transparent plexiglass plate is used on one side of the shell of the experimental device,so that the flow of concrete materials can be observed clearly.The spiral and discharge channels of the experimental device are designed to be detachable,which makes the replacement process in the study easier.This experimental device can effectively carry out a series of experimental research on the amount and arrangement of spiral discharge.This paper summarizes the theoretical analysis,numerical simulation,concrete theoretical modeling and other research status of the screw conveyor for material transportation.Based on the discrete element method,the concrete spiral discharging model is established,and the influence of spiral arrangement and the shape of distributing channel on the discharging uniformity is studied.The reliability of numerical simulation prediction results of concrete spiral discharge depends on the accuracy of physical parameters of DEM model.Therefore,the model parameters are calibrated and analyzed by the flow experiment of fresh concrete,so that the macro flow characteristics of concrete in the simulation analysis are consistent with the experimental results.In order to improve the performance of the multi spiral concrete spreader,ensure the uniformity of the output materials,the uniformity of the output materials and the stability ofthe power consumption,based on the concrete DEM model,this paper studies the two factors of the spiral arrangement and the shape of the discharge channel,which affect the movement of the material particles in the concrete spreader,the difference of the material stacking height and the uniformity / uniformity / specific work of the distribution Impact on consumption,etc.The results are compared with the experimental results,and a more optimized concrete distributor structure is selected.The accuracy of the discrete element method(DEM)is verified by testing the parameters of discharge,uniformity and power consumption at different screw speeds.On this basis,the paper studies the arrangement of the screw in the same direction,opposite direction,centripetal direction,reverse direction and the section of the discharge channel in the U-shape,trapezoid and rectangular operation,and carries out the comparative experiments in the aspects of the uniformity of distribution,the quality of residual materials,the situation of blocking materials,and the difficulty of cleaning,and then selects an optimal arrangement of the screw and the optimal section of the discharge channel,so that the distributor can improve the distribution uniformity Uniformity,reduce shutdown times.It is of great significance to improve the performance of the spiral concrete spreader by studying the influence of the spiral arrangement and the shape of the discharge channel on the uniformity,homogeneity and specific power consumption of the distribution in the spreader.