| The vertical screw conveyor is a continuous conveying equipment which makes the material rise along the machine trough by the spiral rotation.It is widely used in granary,wharf,brewing and other fields.In recent years,vertical screw conveyor with its simple structure,convenient maintenance,long life,small volume,low noise,good sealing and many other advantages,in the field of vertical food lifting and transportation has gradually become the mainstream equipment.However,the multi-objective optimization design of vertical screw conveyor is a big technical problem that has been troubling designers for a long time,which makes the equipment conveying performance and high reliability gradually become the prominent problem of grain vertical screw conveyor.In this paper,an effective and feasible multi-objective optimization design scheme for the vertical screw conveyor is established.EDEM software is used to conduct single factor experiment on each design parameter of the vertical screw conveyor to analyze the influence of each factor on the conveying performance.In order to clarify the relationship between design parameters and transport performance,an orthogonal test table was established to test and a response surface model of transport performance was established.Finite element analysis software ANSYS was used to complete the reliability analysis of the helix structure.Finally,NSGA-II algorithm is used to complete multi-objective optimization of vertical screw conveyor screw.The main work of this paper is as follows:(1)The conveying process of vertical screw conveyor was analyzed.In the process of conveying,the movement and force of materials are analyzed theoretically;The single factor experiment of the main design parameters is carried out by EDEM software,and the influence of each parameter on the conveying performance was analyzed.(2)The conveying performance index model of vertical screw conveyor is established.The pitch,blade diameter and shaft diameter of the conveyor are selected as the structural parameters;the running speed and material filling coefficient are selected as operating parameters,and the conveying flow rate and energy consumption are taken as conveying performance indicators.EDEM software was used to carry out orthogonal simulation experiment on the conveying process and statistical analysis of the experimental results.According to the principle of least square method,response surface models of conveying capacity and energy consumption were established by MATLAB data fitting,so as to obtain the connection between each design parameter of vertical screw conveyor and conveying performance.(3)The reliability analysis of the screw body of vertical screw conveyor is carried out.As the core component of the equipment,the spiral structure should have sufficient reliability.This paper analyzes the reliability of the spiral structure through the PDS technology in ANSYS and calculates the reliability of the spiral structure.The relationship between the main design parameters and reliability of spiral structure is found out,which provides an object for multi-objective optimization design.(4)Multi-objective optimization of vertical screw conveyor screw.The mathematical model of helical optimization aiming at throughput,energy consumption and reliability was established,and the objective function was solved by NSGA-II algorithm.After the optimal solution is obtained,the experimental verification shows that the transportation performance can be taken into account while the reliability is guaranteed,thus confirming the reliability of the optimization results.In this paper,discrete element analysis software,ANSYS software,orthogonal test method and NSGA-II optimization algorithm are used to provide theoretical and methodical guidance for the analysis of the performance and reliability of vertical screw conveyor and the multi-objective optimization design of the spiral structure of vertical screw conveyor. |
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