Numerical Simulation And Structural Optimization On The Air Distribution Plate Of Fluidized Bed Dryer

Lignite drying by fluidized bed is an important way to improve the quality. For fluidized bed, air distribution plate plays a decisive role of fluidized quality. There are many air distribution plate structures, but because of the special high-temperature environment, original straight holes or inclined holes are still mainly used on fluidized bed drying equipment.In this paper, For fluidized bed drying air distribution plate, several structural improvement measures are proposed. Based on excellent lateral flow pattern plate and cheap straight hole type plate, combined with the two types of features and advantages, Four new air distribution plate structures are designed Innovatively. Named respectively, “Indined hole type air distribution plate”,”Rotary indined hole type air distribution plate”,“Convective hexagon type air distribution plate” and “Umbrella separated cap-plate type air distribution plate”.After four different 3d structures are established, reasonable meshing, numerical method and boundary conditions are given. 3d numerical simulation of single-phase flow is carried out on four fluidized bed models installed with four different air distribution plates by FLUENT software. A series of simulation results and the experimental results show the simulation results’ correctness.The umbrella structure is considered to be the best by comparative analysis of several parameters, they are air flow velocity vector graphics, the axial pressure drop, radial static pressure curve and air distribution mentality and so on. Through lignite drying thermal experiments, drying efficiency and drying evenness is contrasted under the same parameters to four fluidized bed models which are respectively installed four different air distribution plates. Experimental results show that the structure which is installed with umbrella separated cap-plate type air distribution plate whether drying efficiency or drying evenness is the best, The simulation results also proved the correctness.For umbrella structure, the opening rate is studied within a reasonable range. They are 2.24%, 5.04% and 8.95%. 2d numerical simulation of multi-phase flow is carried out on three kinds of opening rate, 2.24% is considered to be the best rate for RMS,particle distribution and gas-solid velocity vector graphics and so on. Through lignite drying efficiency experiment for different opening rate fluidized bed. The results show that 2.24% is the best rate for umbrella structure. At the same time, the simulation results prove it.