Solid-Flow Pattern for Free Drainage in MPBAC Based on WholeField Residence Time Distribution

The solid-flow pattern of free drainage is important to the design of a silo and prediction of the discharge rate of granular systems, and the flow pattern in the monolayer pebble bed formed in the two-dimensional (2D) silo reveals the rules of solid-flow pattern in a three-dimensional (3D) silo. The whole-field PTV platform here contains a monolayer pebble bed with adjustable configurations (MPBAC) and corresponding programs for particle recognition, amending, and matching. Using this platform, all particles in the beds are traced in the whole process of free drainage. The average mass flow rate and the whole-field residence time distribution (RTD) are obtained at different outlets. The effects of outlet size, inclination angle, and outlet configurations on the average mass flow rate and the solid-flow patterns are analyzed and discussed. In the free-discharge experiment of MPBAC, the effect of inclination angle on the solid-flow pattern is more significant than that of outlet size. The particle flow is more likely to be the funnel pattern when the circular-arc-type and the cycloid-type outlets are adopted. The final solid-flow pattern under different conditions (different outlet sizes and configurations and different inclination angles) provides a useful reference for future prediction of free discharge in a 2D silo with similar dimensions and configurations.

Automated summary

This study investigates the flow patterns in a monolayer pebble bed formed in a two-dimensional silo, revealing the rules of solid flow patterns in a three-dimensional silo. Using a whole-field particle tracking platform, the effects of outlet size, inclination angle, and outlet configurations on the solid flow patterns are analyzed. The findings provide useful insights for predicting free discharge in silos with similar dimensions and configurations.