Numerical Simulation Of Outflow Pressure Screen Separation Process Rotor Parameter Optimization

With the increasing demand for paper quality and variety in China,the finer degree of pulping and papermaking process and the demand for screening equipment in paper-making enterprises are improved.In the paper industry,the low energy consumption and large capacity screening equipment has become an important research direction.At present,with the rapid development of computer hydrodynamics(CFD),using CFD technology to design and optimize the pulp screening equipment has become an important research topic.In order to obtain a more ideal screening effect,this paper mainly studies the working principle of the external flow pressure screen and the structural parameters and operating parameters of the rotor.The main work is as follows:(1)The internal screen process of the pressure screen is modeled,and mesh is divided.Through the simulation process and analysis of the model,the pressure,velocity and velocity vector of the internal pulp flow in the pressure screen,and the pressure and velocity cloud diagrams distributed on the rotor are obtained.By comparison and analysis of the simulation results,the internal flow of the pulp in the pressure screen is obtained,which is the basis of the analysis and optimization of components.(2)Establish a two-dimensional model of the flow field around the rotor and conduct numerical simulation on the model to obtain the pressure and velocity distribution cloud around the rotor.Analyze the pressure distribution clouds,velocity distribution clouds,pressure scatter plots on the inner surface of the screen drum,and outlet speeds of the screen seams under different clearances,different speeds,and different rotor shapes,etc,The rotation of the rotor drives the movement of the pulp to enhance the cleaning capacity of the pressure screen with the increase of the rotor line speed.On the basis of the better line speed,the optimized clearance values and rotor shape are obtained.(3)The response surface analysis experiment was conducted by considering the three variables including the clearance between rotor and screen drum,the rotor linear velocity and the rotor shape.Through the regression analysis of the three factors,the optimal combination of the three factors was obtained:the clearance between the rotor and the screen drum is 3.49mm,the rotor linear velocity is 18.72m/s,and the rotor rake angle is 91.65°.Under the optimal combination,the pulp has better cleaning ability to the screen drum.