Simulation Analysis And Experimental Research On The Influence Of Screw Parameters On The Working Performance Of Distributor

The screw is the core component of the concrete distributing machine.The selection of its geometric parameters and physical parameters directly affects the distributing performance and working efficiency of the concrete distributing machine,and it is also the key to reducing power consumption and improving uniformity of the distribute.Aiming at the influence of the screw structure parameters on the working performance of the spreader,scholars at home and abroad have carried out a lot of research on the problem of single-screw conveyors,while the research results on the working performance of concrete spreaders in the form of multi-screw are relatively small.In the "Thirteenth Five-Year" national key research and development plan"Research on the technology and equipment of digital intelligent and precise distribution of concrete for complex prefabricated components"(Subject No.2017YFC0704003).The system research is focused on the influence of the screw structure parameters on the working performance of the multi-screw concrete distributor.The discrete element simulation software is used to simulate the material conveying process and the spiral discharge experiment.The screw torque,the motor power and the discharge port are combined.The mass flow rate is used as an evaluation index that affects the working performance of a multi-screw spreader.The influence of three structural parameters,such as pitch,diameter of the spiral blade,and thickness of the spiral blade,on the performance of the spreader is investigated.The optimal parameter combination of the experimental device of the distributor is obtained through orthogonal experiments.The sensitivity of the three screw structure parameters on the performance of the distributor is obtained,which provides a basic scientific basis for the optimization design of the structure of the multi-screw concrete distributor.In view of the structural mechanism of the multi-screw concrete distributor,the structural parameters of the screw and the working parameters of the screw conveying device are determ ined,and the movement of the concrete particles.and the force on the screw surface during the screw conveying process are analyzed to provide a theoretical basis for the simulation analysis.Based on the working principle of the multi-screw concrete distributor,the process of determining the main working parameters of the distributor and the calculation method of the driving power of the screw conveyor of the multi-screw distributor are discussed.Based on the discrete element method,the Hertz-Mindin bonding contact model is selected as an improvement Discrete concrete element model.Through independent research and development of a new multi-screw spreader experimental device with simple structure,innovative design,flexible adjustment,and convenient disassembly,it provides equipment support for the experimental research of different screw structural parameters of the spreader,and conducts concrete transportation experiments and discrete element values.Simulate and analyze the variation law of screw torque,motor power and conveying capacity,further verify the applicability of the discrete element model,and provide a theoretical basis for the study of the influence of screw structure parameters on the working performance of multi-screw concrete distributors.The research shows that with the increase of the pitch and the diameter of the spiral blade,the particle conveying speed increases,the screw torque and the power consumption of the motor increase,and the unit mass flow rate at the outlet increases;The flow rate increases.When the thickness is 3.5mm,the mass flow rate changes more smoothly with time,and the cloth uniformity is better.According to the single-factor test and optimization analysis,the optimal parameter combination of the experimental device of the spreader used in this paper is determined:the pitch is 40mm,the diameter of the spiral blade is 50mm,and the thickness of the spiral blade is 3.5mm.The optimized screw torque is reduced by 29%,and the motor power is reduced.Decreased by 31%,and the mass flow rate increased by 33%.Finally,the orthogonal test method was used to find out the influence of three factors on the working performance of the screw.The order of sensitivity from the largest to the smallest is:spiral blade diameter D>pitch S>spiral blade thickness ?.This conclusion can be optimized for the structure of multi-screw concrete distributors and provides a reference for design.