The Numerical Simulation Research Of Three Sections Dense Medium Cyclone Used In Pressure Separation Of Middlings

In this paper,the development and technical status of three product heavy medium cyclone are briefly introduced.The reason why the clean coal was carried in middlings in three product dense medium cyclone coal fine is analyzed and the current commonly methods used in middling's separation are listed.On that basis,to solve the problem that clean coal carried in middlings,three sections heavy medium cyclone is putting forward.The three sections heavy medium cyclone is based on the three product dense medium cyclone.A tangential aperture is opened in the end of the second section cyclone's overflow pipe and the middlings are separated in third section cyclone.This structure can make full use of the residual pressure in second section cyclone and provide impetus for third section cyclone.At the same time,water supply pipe is put up on third section cyclone which not only can adjust the density,but also can increase the separation impetus.In this paper,the numerical simulation technique was used to study the theory of the three sections dense medium cyclone.By means of numerical simulation,the distribution of internal flow field is analyzed.To explore the structural feasibility of the three sections dense medium cyclone,the results of numerical simulation was compared with experimental results.We can know:(1)The design of the tangential aperture in the end of the second section cyclone's overflow pipe was analysed by the numerical simulation technology.To ensure the optimal size,the numerical simulation results was compared;(2)To analyse the numerical simulation results of velocity field,we select different sections to get the tangential velocity and axial velocity distribution curve.Comparing the numerical simulation results with Kelsall's experiment data,the velocity field distribution of three sections dense medium cyclone accord with the requirements of separation;(3)Through analysing the numerical simulation results of pressure field,we know that the pressure field distribution of three sections dense medium cyclone is well.The negative pressure region is stabilize and the area is according with the requirements of separation.