| Continuous mixer has the advantages of high productivity,low energy consumption,and stable working process.It is mainly used for the production of stabilizing soil,roller compacted concrete and other dry hard materials.When it is used to prepare C30,C40 and other strength ready-mixed concrete,mixing will occur shortcomings such as short time and unstable concrete quality.In response to this problem,this article conducted a special study on the continuous twin-shaft mixing process and mixing parameters,which has important practical value for improving the performance of the continuous mixer and the quality of concrete.This paper adopts the method of combining theoretical analysis and computer simulation.First,starting from the continuous mixing mechanism of concrete materials,the working characteristics of continuous mixing are analyzed,and the principle of selection of continuous mixing parameters is proposed.Based on the main mixing parameters of the twin-shaft mixer,the influence of the main parameters on the continuous mixing process,mixing quality and productivity is analyzed,and the reasonable value of the main parameters is obtained;according to the specific model of the continuous twin-shaft mixer,which decide the different parameter of blade installation angle,blade linear velocity,central intersection area,biaxial blade layout and other parameters of the ready-mixed concrete,and on this basis,the mixer model with different parameters was established;the two-phase flow of aggregate and mortar was used to establish.The discrete element model of ready-mixed concrete adopts the "Hertz-Mindlin with JKR" contact model,and calibrates the relevant parameters through the GEMM general database,slump virtual test and L box virtual test;finally,it is carried out in the EDEM discrete element software.The multi-factor orthogonal simulation experiment analyzes the influence of different mixing parameters on productivity and mixing uniformity,and determines the best parameters and their matching.The simulation test results show that the best parameters for the opposite arrangement of the mixing arms are: blade installation angle 25°,mixing linear speed 2.0m/s,the proportion of central intersection area 15%,and adjacent blades axial clearance 1.5D;Stirring arm The best parameters for single arrangement are: blade installation angle 25°,mixing linear speed 2.0m/s,the proportion of central intersection area 15%,adjacent blade phase angle 60°;compared with opposite arrangement,when single stirring arm meet the requirement of productivity,the mixing uniformity is better. |
