| According to engineering practice,SBS modified asphalt has the characteristics of improving the hot and soft deformation and cold brittle crack of the road surface,which can improve the performance of the road surface,reduce the maintenance cost of the later maintenance,and achieve the purpose of extending the service life of the road.The utility is unmatched by other asphalt materials,so it is widely used in high-grade highway asphalt pavement construction.In the production process,in order to improve the material quality of the SBS modified asphalt,the modifier and the matrix asphalt mixture need to be stirred and mixed uniformly in the stirring tank before shear grinding.Based on the above background,the simulation analysis of the modified asphalt mixing equipment is carried out in order to improve the performance parameters of the mixing equipment and improve the mixing effect of the modified asphalt.Based on the research of the existing modified asphalt production process,this paper designs a new modified asphalt production process and conducts in-depth research on the important components of the mixing equipment.Take the JD1000 asphalt mixture mixing plant as an example to calculate the production capacity of the asphalt mixing equipment and determine the structural dimensions of the mixing tank and the agitator.The CFD simulation software ANSYS /FLUENT was used to,model the three-dimensional modeling of the mixing equipment,and to mesh and solve the calculation.Firstly,the key factors affecting the uniform mixing of modified asphalt under the action of single-layer agitator,such as the type of agitator,the number of blades,the blade angle,the rotational speed,the installation position of the blade and the diameter of the blade,are studied.According to the simulation results,the liquid phase velocity diagram of the asphalt and the solid phase concentration diagram of the modifier under the action of different structure stirrers are compared and analyzed,and the most reasonable agitator structure size parameters are obtained.In addition,comprehensive consideration of the height of the mixing tank and the efficiency of mixing,combined with the characteristics of straight blade and oblique blade,two sets of double-layer agitators are designed,which are straight-gradient-alternated impeller and straight-upper-gradient-lower impeller.By analyzing the liquid phase velocity diagram of the modified asphalt and the solidconcentration distribution diagram of the modifier under the action of the two sets of combined agitators,it is concluded that the straight-gradient-alternated impeller is more conducive to the uniform mixing of the modified asphalt in the stirred tank.Finally,according to the modified asphalt production process,the flow chart of each program of the automatic control system is designed.Selecting and designing various hardware of the equipment control system,and then the use Siemens PLC programming software STEP7-Micro/WIN4.0 SMART to write the program of modified asphalt automatic production control system. |
