Research On Unloading Efficiency And Its Influencing Factor Of Hopper Vehicle

Abstract:Railway hopper vehicle assumes the most transport task of bulk goods such as coal, grain and ore. It guarantees the efficiency of cargo turnover and has made an important contribution to the development of the national economy. In order to further improve the hopper vehicle unloading efficiency, the influence factors of the hopper vehicle unloading efficiency based on the theory of discrete element method was studied.Simulation triaxial test was used to get micro-parameters of granular. Simulation of three axis test improved the accuracy of micro-parameters and has certain value of promotion in the area of bulk goods transportation. The flow pattern of bulk grain and the pressure distribution of inner wall under the unloading process of hopper vehicle was also analyzed. The unloading efficiency of hopper vehicle in different bulk properties was compared. To take some appropriate measures to improve the feasibility of bulk properties was discussed. The unloading efficiency of hopper vehicle in different end wall angle was compared and a reference for the choice of end wall angle was provided. The theoretical analysis and numerical simulation was combined to study the geometry optimized design for hopper vehicle. The following conclusion was obtained:(1) The unloading efficiency of hopper vehicle decreases with the increase of friction coefficient of particles. The unloading efficiency of hopper vehicle is most sensitive to changes of friction coefficient when it is in [0.10,0.15]. Considering the cost of changing particles’physical properties, some appropriate measures can be taken to control the change of friction coefficient in this interval to improve the unloading efficiency of hopper vehicle.(2) The unloading efficiency of hopper vehicle decreases with the increase of bond strength of particles. The unloading efficiency of hopper vehicle is most sensitive to changes of bond strength when it is in [14kPa,18kPa]. Considering the cost of changing particles’physical properties, some appropriate measures can be taken to control the change of bond strength in this interval to improve the unloading efficiency of hopper vehicle.(3) The unloading efficiency of hopper vehicle increases with the end wall angle. The improvement of the unloading efficiency of hopper vehicle is not obvious when the end wall angle is over50°. Considering the hopper vehicle effective volume and unloading efficiency, this paper suggests that the end wall angle should be controlled in [45°,50°]. In addition, the unloading efficiency of hopper vehicle can be improved about25%after installing a liner made up of UHMW PE on the inner wall.(4) The unloading efficiency of hopper vehicle can be improved about25%after the shape optimization based on the principle of equal cross section area contraction.