Study On Flow Field And Particle Trajectory Behavior Of Cross-flow Guided Sieve Plate Dryer

For non-spherical macromolecule polymer particles,the gas distribution plate of traditional vibrated fluidized bed has some shortcomings,such as non-uniform gas distribution and easy leakage of particles.Aiming at the design defect of traditional vibrated fluidized bed,Aiming at the design defect of traditional vibrated fluidized bed,the design concept of fish-straight gas distribution plate is put forward and its structure design is carried out.Firstly,the flow field of air in five vibrated fluidized beds with different gas distribution plates was studied by CFD technology.The results show that vibrated fluidized bed with fish-straight gas distributor and fish-scale hole gas distributor has a large circulation of air in the whole basin.For fish-straight gas distributor,air will generate a micro-eddy at the back of the scale hole.For the scale hole gas distributor,air will generate advection flow in the area above 10 mm from the surface of the distribution plate.However,the air distribution in a vibrated fluidized bed with a straight-hole gas distribution plate is very uneven.Secondly,based on the analysis of single-phase flow field in a vibrated fluidized bed,CFD-DEM technique is used to simulate the particle motion in a vibrated fluidized bed with fish-straight gas distributor.It is found that the residence time of particles in the vibrated fluidized bed is between 1.89 s and 18.46 s,the jump height of particles is between 4.8mm and 16.8mm.Under certain conditions,the shape of particles can affect the residence time of particles.Due to the influence of the structure of the vibrated fluidized bed and the air velocity,the average velocity of particle in the vibrated fluidized bed has stable stage and unstable stage.The average velocity of large particles is lower than that of small particles.If the opening ratio of the gas distributor is increased and the air inlet velocity is reduced,the difference between the average velocities of two different particles will be smaller.In addition,the trajectories of two kinds of particles with different sizes in the vibrating bed show a parabolic shape.Finally,according to the results of flow field simulation and particle motion analysis,the rationality of the design of fish-straight gas distribution plate was verified,and the formulas of particle residence time and jump height with respect toair inlet velocity are given.,which provided theoretical basis for the industrialized design of vibrated fluidized bed drying non-spherical macromolecule polymer particles.