Wear mechanism of high-concentration filling pipeline based on aggregate migration
The wear of high-concentration filling pipelines poses a hazard to mine safety,but the underlying wear mechanism remains unidentified.CFD-DEM coupling method was used to simulate the abrasion of high-concentration filling pipeline,as well as the aggregate migration,the contact between aggregate and pipe wall,and the wear mechanism of filling pipeline was revealed by theoretical analysis and in-situ test.The results indicate that when the slurry supporting capacity is sufficient,the solid-liquid phase in the pipeline exhibits a plug flow,the aggregate migrates to the center of the pipeline,anti-friction slip layer is formed on the pipe wall,and wear around the pipeline is uniform;on the contrary a sliding bed is formed by the aggregates at the bottom of the pipeline,and the wear of pipe bottom is significantly higher than that of other positions.The force exerted by the sliding bed on the pipe wall is 2.46 to 2.76 times greater than that of plug flow,and the wear on the bottom of the pipeline under a sliding bed is 1.48 times greater than that under plug flow.The trajectory of the aggregates near the pipe wall exhibits a waveform pattern,with the aggregates making sliding movements while contacting the pipe wall at a small angle.The tangential force exerted by the aggregates on the pipe wall is 27.44 to 30.84 times greater than their normal force,indicating that pipe wear is primarily caused by tangential scraping from aggregates.Unsteady transportation,rough pipe wall and excessive slurry concentration will degrade the wear reduction effect of the slip layer.Based on the simulation results,six measures for preventing and controlling wear are proposed,which can serve as a reference for related mines.
high-concentration fillingpipe abrasionaggregate migrationwear mechanismCFD-DEM simulationwear prevention and control
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