Application of discrete element technology in optimizing design parameters of belt end sampler

Based on the discrete element simulation technology,the sampling motion parameters at the end of coal conveying belt were studied.By changing the moving speed of the end sampling and cutting bucket in the material flow model of 50 mm diameter particles with cross section of 4×30,the kinds and quantities of particles collected were counted.The results show that with the increase of the moving speed of the cutting bucket from 1 m/s to 2 m/s,the total number of particles collected decreased from 2 006 to 958,which is equivalent to the sampling width of 835 mm to 399 mm in the middle of the belt.In the model of dividing 4×30 material flow into 30 kinds of particles horizontally,there is no correlation between the standard deviation of particles collected by sampling bucket and cutting speed.The standard deviation of particles collected by sampling bucket is the largest at cutting speed of 1.5 m/s,which is 3.69,and the smallest at cutting speed of1 m/s,which is 2.43.In the model of dividing 4×30 material flow vertically into 4 kinds of particles,the standard deviation of particles collected by sampling bucket is weakly linear with cutting speed.The maximum standard deviation is 84.98 at cutting speed of 1 m/s and 53.19 at cutting speed of 1.7 m/s.The results show that the effect of the primary sampler at the end of belt on the end of sampling direction and the bottom is not ideal at different cutting speed.In the design,the length of the inlet and outlet of sampling hopper should be increased in the direction of belt to improve the effect of collecting coal particles at the bottom.