Optimization of geometric parameters of screw feeders for feeding cement mixtures

Abstract

Modern requirements for the efficiency of construction production necessitate the improvement of technological equipment for the transportation and supply of cement mixtures. Screw feeders, which are widely used in concrete mixing plants and dry mix plants, require optimization of geometric parameters to increase productivity and reduce energy consumption. The research is aimed at developing mathematical models and methods for calculating the optimal design parameters of screw feeders, taking into account the rheological properties of cement mixtures. An integrated approach was applied, including discrete element methods (DEM), experimental modeling, and analytical calculations. The experimental base of the study consisted of 150 experiments with varying the screw diameter from 100 to 320 mm, the pitch of the screw surface from 0.8 to 1.2 diameter, the rotation speed from 50 to 200 rpm and the bulk density of cement mixtures from 1200 to 1800 $kg/m3$. It was found that the optimal pitch-to-diameter ratio is 0.95-1.05, while ensuring a maximum productivity of 45-62 m3/h. The filling coefficient of the housing reaches maximum values of 0.85-0.92 at an angle of inclination of the screw surface of 18-22°. Energy consumption is reduced by 25-30% when using optimized geometric parameters compared to traditional designs. The criteria dependences between the feeder performance and a set of dimensionless parameters, including the Froude number, the filling criterion and the geometric factor, are determined. The results of the study make it possible to increase the efficiency of transportation of cement mixtures and can be used in the design of a new generation of screw feeders for the construction industry.