Research On The Wear Of Scraper Conveyor Chute Based On DEM

Scraper conveyor is the key conveying equipment in fully mechanized coal mining face,and plays a significant role in coal mine production.The scraper conveyor chute is the load-bearing part of bulk coal and Shearer.Its working environment is bad,working conditions are complex,and the wear of chute is very serious.As the core component of scraper conveyor,the wear failure of the chute often leads to the overall failure of the scraper conveyor.Discrete element method?DEM?has great advantages in dealing with the problems of bulk mechanics.Combining DEM with classical wear model,it provides a new method for studying the wear of chute.In this paper,the chute wear was studied by using the DEM.The wear mechanism and wear regularity of the chute were obtained.It could predict the wear of the scraper conveyor chute,provided theoretical guidance for the applicability of the chute in different mines,and had important significance for improving the service life of the chute.The abrasive wear tester is specially designed for the wear problem of the chute,which has strong applicability for the study of the wear problem of the chute.On the basis of abrasive wear tester,a discrete element wear model was built by EDEM to study the chute wear.The working state of the abrasive wear tester was simulated and the wear mechanism of the chute was preliminarily studied.The results showed that the main wear type of the scraper conveyor chute was abrasive wear,which included two-body wear and three-body wear.Within a wear cycle,the wear amount of three-body wear was about 32.84 times of that of two-body wear,and the severity of three-body wear was much greater than that of two-body wear.The three-body wear of the chute required certain conditions,that was,the coal particles between the scraper?chain?and the middle plate were in a certain position and posture,and the coal particles were acted by the normal force of the scraper?chain?and the middle plate,thus forming the three-body abrasion of"scraper?chain?-bulk coal-middle plate",which also led to the randomness of the three-body abrasion and the uneven abrasion of the chute.The wear morphology and location of the simulated middle plate sample were compared with those of the actual test,and good consistency was found between the two,which verified the correctness of the discrete element wear model.In order to obtain the wear regularity of the chute,based on the discrete element wear model,the physical properties and working conditions of coal were studied.The influence of Poisson's ratio,shear modulus,density and hardness of coal on the wear of chute was studied from nine levels.Within the scope of study,the wear amount increased with the increase of Poisson's ratio,shear modulus,density and hardness.The wear constant had the most significant effect on the wear amount of chute sample(the difference between maximum wear depth and minimum wear depth was 1.209×10^-7mm),the shear modulus was significant(7.218×10^-8mm),Poisson's ratio had little effect(1.725×10^-8mm),density had the smallest effect(1.158×10^-8mm);wear constant had a highly strong linear relationship with wear amount,R²=0.9908,shear modulus had a strong linear relationship with wear amount,R²=0.8232;the effects of speed and particle size on the wear of the chute were studied from three levels.Within the scope of study,the wear amount increased with the increase of speed and particle size.Based on the actual structure of scraper conveyor,the coupling model of scraper conveyor chute was established by EDEM and RecurDyn.The working state of chute was simulated under sprocket drive.The mechanical relationship between bulk coal and chute during wear process was analyzed,and the wear mechanism of chute was further studied.It was found that the coal had"Brazil fruit effect",that was,in the state of vibration,the larger particles would move to the upper layer,the smaller particles would settle to the lower layer,and the wear of the chute was mainly caused by the smaller particles in contact with it;the three-body wear of the chute needed certain conditions,and the coal particles between the scraper?chain?and the middle plate were in a certain position,the position and posture of the coal particles were affected by the normal force of the scraper?chain?and the middle plate,which forms the three-body wear of the"scraper?chain?-bulk coal-middle plate".When the coal particles acted on the surface of the middle plate alone,only the two-body wear of the"bulk coal-middle plate"could be formed.Under the working condition of the scraper conveyor,the movement and force of the scraper and the chain were in constant fluctuation.The state also led to the randomness of the three-body wear and the uneven wear of the chute.The wear of the chute was mainly caused by the three-body wear,and the severity of the three-body wear was much greater than that of the two-body wear.