Kinematics Model And Numerical Simulation Of Bulk Materials During Gas-solid Separation

The bulk material accounts for an important share of cargo throughput in world ports,Pneumatic ship unloader has the advantages of simple equipment structure,high efficiency,small clearance,and low pollution,and is widely used in port logistics.At present,the research on pneumatic ship unloader mainly focuses on the reclaiming device and pipeline wear.The research on the gas-solid separation device of pneumatic ship unloader is less.The object is to study the motion characteristics of gas-solid separation of bulk materials in a volumetric separator,and to numerically simulate the motion process of gas-solid separation of bulk materials.The main research work and results are as follows:The structure of the volumetric separator was reasonably simplified,and the gassolid two-phase flow formed by the granular material and the conveying gas was analyzed.The motion state and force of the granular particles in the granular material were studied,and the dispersion The motion model of bulk particles is analyzed by continuous fluid phase,the gas phase continuous equation is established,the appropriate turbulence model is selected for analysis,and the general motion process of granular particles in the volumetric separator is explained.The CFD-DEM coupling platform was used to simulate the gas-solid separation motion of the granular materials.The internal conditions of the model were analyzed when the granular materials flowed in the gas-solid dilute phase and gas-solid semidense phase flow in the conveying pipe.The change of the flow field and the change of the particle trajectory of the granular material are analyzed.The gas-solid separation motion of the granular material and the gas is analyzed when the granular material enters the volumetric separator under different flow conditions under the action of the gas.The results show that in the state of gas-solid dilute phase and gas-solid semi-dense phase flow,the separation process of granular particles and transported gas mainly occurs after the collision of granular particles and the wall of the volumetric separator.The gas is in a relatively low speed state,and the conveyed gas is not enough to promote the upward movement of the dispersed particles to complete the separation process.The analysis of the particle trajectory of the scattered particles found that there was a certain degree of particle divergence during the initial collision of the scattered particles,and the particles might escape from the air outlet.The effects of various factors such as different operating conditions,particle attributes,and separator parameters on the separation characteristics of bulk materials in a volumetric separator were studied.It was found that for the gas-solid separation movement of bulk materials,due to the large size and large separator size,Most factors have little effect on this separation behavior.In the steady state,the volumetric separator has good separation performance for bulk materials in different flow states.For the influence of the internal flow field of the model,when the granular material is in two flow states,the conveying wind speed has the largest effect on the total internal pressure value and pressure difference of the model,and the mass flow rate of the granular material,the initial velocity of the granular material,the particle radius,and the particle Density has a weak effect on the total internal pressure value and pressure difference of the model.The particle shape,the angle between the feeding pipe and the horizontal,and the position of the air outlet have the weakest effects on the total internal pressure value and pressure difference of the model.