Development of Models Relating Screw Conveying Capacity of Concrete to Operating Parameters and Their Use in Conveyor Operating Strategies to Consider Batch Production

Abstract

The screw conveyor is the key equipment used to realize the casting and forming of concrete in prefabricated components (PC), and its performance affects the PC shape, quality, and cost. In batch production, there is a process variable, the residence time. It is affected by the quality of the downstream vibration process. This also results in operating parameters that are difficult to match to the time scales. Eventually, it can lead to problems such as low casting efficiency or poor molded quality. In this paper, the DEM simulation method is used to explain and quantify the relationship between the screw conveying capacity and three important operating parameters: the screw’s outer diameter, residence time, and screw speed. The axial and radial velocity vectors are used as features to analyze the changing rule of particle motion trajectory and mass flow rate. Based on the simulation data, the operating parameters and the mass flow rate are forward-fitted to establish the prediction model of the screw conveying capacity. In addition, the residence time is backward fitted from the screw speed and mass flow rate. It is used to estimate the concrete workability. Furthermore, the fitted forward and backward models explore how to propose feasible operational strategies to achieve automatic discharge during batch production.

Keywords

• screw conveyor
• mass flow rate
• residence time
• batch production management