Experimentaland Numerical Investigation Of Particle Flow And Mixing Characteristics In Fluidized Bed

The internal circulating fluidized bed(ICFB)has unique advantages in the treatment of refused derived fuel(RDF)combustion,and the gas-solid two-phase flow characteristics in the fluidized bed have a direct influence on the interphase heat and mass transfer and chemical reaction rate.This paper focuses on the cold clapboard type inner circulation flow mechanism of single particles in fluidized bed and two-component particle mixing characteristics,and through the calculation of fluid mechanics coupling discrete element method(CFD-DEM)on flow field and mixing of particles in the bed was simulated.This paper focuses on the flow mechanisms of single particle and binary particles mixing characteristics in a cold clapboard type internal circulating fluidized bed,and employed the computational fluid dynamics coupling discrete element method(CFD-DEM)to simulate the particle movement and the flow field distribution.The Euler method is used to deal with the continuous gas field and the Lagrange method is used to track the single particle motion in the discrete particle field,from the multicomponent particle layer of the mixing mechanism was studied.Firstly,the coupled CFD-DEM was employed to investigate the cylindrical RDF mixing characteristics of referring to the 3D rectangular spouted fluidized bed experiments explored by Goldschmidt et al.,and the calculated results agree well with the experimental results.And then,designed and built up cold clapboard type internal circulating fluidized bed test,visual observation was carried out using a high-speed camera,focus on the characteristics of tracer particles and low intake air distribution ratio for the orifice particle circulation effect.Focus on the influence of particle properties as well as high and low intake gas distribution ratio on the quantity of circulating particles at the orifice.Finally,the CFD-DEM numerical simulation was carried out under the same conditions.The results show that the reasonable high and low intake gas distribution ratio is a key factor to achieve particle internal mixing,and pointed out that the binary particles mixing degree will increase with the increase of particle circulation quantity at the orifice.The internal circulating fluidized bed can further improve the mixing state of the material in the bed.The finding results obtained from the experiments and numerical simulation of internal circulating fluidized bed will provide practical value in the future.