Abstract：In ord er to analyze the influence of the screw shaft diameter on the performance of the screw conveyor, the method of granular mechanics was used. By means of the software of discrete element method, the model of screw conveyor was verified. Through choosing a group of variable screw shaft and keeping the model parameters still, the method of periodic boundary was adopted, and the influence of different diameters for screw shaft on the performance of the screw conveyor in the different rotational velocity were discussed. The results show that with the increase of rotational velocity, the average particle velocity increases, the energy dissipation increases as the same screw shaft, and the normal force between particles increases, the steady of the conveying particle reduces. With the increase of diameter of the screw shaft, the number of particles increases in the unit volume and the depth of the fluidized layer increases.The better match has been got of the test is that the screw shaft diameter is 13 mm and the rotational velocity is 900 r/min.

Keywords：screw conveyor; screw shaft; conveying performance; DEM