Numerical simulation of hydraulic transport of large size coal particles in deep underground
China boasts abundant deep underground coal resources with excellent quality and great commercial min-ing value.However,due to the huge engineering cost,it is difficult to study the deep coal mining and transportation technology through experiments.It is necessary to use the numerical simulation method based on the computational fluid dynamics-discrete element method(CFD-DEM)coupling scheme to study the hydraulic transport of large coal particles in deep underground to determine the mining and transport scheme.To overcome the drawback that the mesh size is restricted by the particle size in the CFD-DEM scheme,the calculation method of particle volume fraction is improved based on the statistical kernel method(SKM)algorithm,and the three-dimensional Gaussian function is used as the weighting kernel function to describe the particle volume distribution more accurately.Additionally,the characteristic point subdivision method is adopted to replace the traditional grid loop search method in order to improve calculation accuracy and efficiency.The flow state of coarse and dense particle flow in the hydraulic transmission pipeline and the influence of control parameters on the flow characteristics are mainly investigated in this paper.The optimal initial parameters are obtained by combining the hydrodynamic characteristics of solid-liquid two-phase flow in the transmission pipeline under different conditions and its efficiency and economy analysis in practical engineering.The results show that the prediction errors for local particle volume fraction,particle velocity,and pipe pressure drop at different inlet velocities and particle volume fractions are all within 10%,and the average error is about 5.1%.The particle transport rate Q is positively correlated with the inlet liquid phase velocity and inlet volume fraction,and increases first and then decreases with the increase of particle diameter.The pressure drop increases gradually with the increase of inlet liquid phase velocity,inlet volume fraction and particle diameter.Considering the economic in-dexes of particle transport rate and pressure drop comprehensively,with the increase of imported liquid phase velocity and imported volume fraction,it first decreases and then increases slowly,and with the increase of particle diameter,it first decreases and then increases obviously.When the inlet speed is 3 m/s,the particle diameter is 20 mm,and the inlet volume fraction is 0.08,the economic index P is at its lowest point,and its value amounts to 1 640.
万方数据
维普
