Study on the two-phase coupling migration mechanism of deceleration aggregate and water in coal mine water inrush channel

Currently, perfusing deceleration aggregate is the most effective way to create water-blocking sections for controlling coal mine water inrush disasters. Clarifying the two-phase coupling migration mechanism of deceleration aggregate and water in coal mine water inrush channels is the key to quantitatively determining the deposition and migration distance of aggregate after entering the water inrush channel from the perfusion hole. Based on fluid mechanics, slurry pipeline transportation theory and sediment dynamics, this paper categories the entire migration process of aggregate entering the water inrush channel from the perfusion hole into three motion stages: free fall, curved-throwing, and sliding. The motion and force characteristics of each stage are analyzed, and a theoretical model for single-aggregate sedimentary migration is established. The CFD-DEM method is used to establish a transient bidirectional coupling numerical calculation model of aggregate-water to verify the theoretical model (overall error not exceeding 10%). Finally, based on this research, reasonable suggestions are proposed for the actual engineering of plugging by perfusing deceleration aggregate.