Dynamic Characteristics Research On Internal Bulk Coal Load In Middle Pan Of Scraper Conveyers

The middle pan accounts for largest part in scraper conveyor,and the movement of granular media in it is quite complex.Currently most research on middle pan and bulk coal treat the bulk coal in the middle pan as a continuous whole.It is inaccurate because it isn’t accord with physical characteristics of bulk coal.With the increase of installed power in recent years,it is urgent to conduct deeper research on the load characteristic of scraper conveyor.Establishing an accurate mathematical model of middle pan and bulk coal is the key to further increase the installed power of scraper conveyor.The motion state of the bulk coal in the middle pan is analyzed in this paper,and a mathematical model of middle pan and bulk coal accord with the physical characteristic of bulk coal is established.The main research object is the bulk coal in the middle pan,and the minor research object is the internal force condition of the middle pan.Based on the granular mechanics,the force condition of the scraper and chute sidewall in the stationary state in the internal middle pan were analyzed.The maximum of scraper spacing based on transmission region of the local stress in the bulk coal was calculated.The maximum acceleration of scraper chain according to the stability of transportation process was calculated.The simulation model of bulk coal particle was established in EDEM.The force condition of downspouting base of scraper conveyer was studied,and the cause of high resistance force on coal was analyzed.A method to measure the damping coefficient and stiffness coefficient between the scraper and coal was proposed.The dynamic model of bulk coal load was established with these two coefficients.The effects of blocking chain location on the torque of chain wheel and chain tension was studied.The results show that if the location of blocking chain is closer to the tight sites of machine head and machine tail,the chain tension of machine head and machine tail is greater.The interval of sequential starting was studied.The results show that if the interval is 0s,the torque of machine head and machine tail have the same change.If the interval is 0＜△t<1,the chain tension value of tight sites of machine tail is smaller.