VIP Experiment And Numerical Simulation Of Particle Flow Characteristics In Spouted Bed With Longitudinal Vortex Generator

As an efficient gas-solid contactor,the spouted bed is widely used in many fields,such as drying,coating,waste combustion and gasification.With the continuous popularization of the application scope of the spraying technology and its research,the researchers at home and abroad have proposed various structural improvement measures.For example,the guide tube spouted bed,multi-jet spouted bed,jet fluidized bed,rotary nozzle spouted bed,jet spouted bed and so on.Traditional media are observed in the spouted bed has obvious internal and external characteristics of stratified flow.Lacking of particles in bed radial mixing makes part of the surface of the particles failed to get full use of and the adverse impact on heat and mass transfer within the bed.In view of the above situation,our research group introduces longitudinal vortex generator and longitudinal eddy current technologies to spouted bed in gas-solid two-phase flow process,and through the experiment prove that the longitudinal vortex generator can effectively strengthen the radial motion of particles in spouted bed and phase and to strengthen the bed material in transverse mixing.In this paper,by adopting the combination of the experimental measurement and numerical simulation methods to further explore spouted bed with the longitudinal vortex generator in the gas-solid two-phase movement rule,in order to further applied to the powder-grain of spouted bed half dry water vaporizing the strengthening of the desulfurization process to provide basis of the experimental with no chemical reaction,and provide help to the industrial amplification.Experiment using particle image velocimetry(PIV)to study the several parameters such as static bed height,row number of spoiler,particle size and particle density changing with longitudinal vortex generator in the spouted bed results show that the effect of longitudinal vortex generator on enhancement of particle motion in spouted bed is spatially inhomogeneous.There exist most optimal height of the static bed,at which the effect of longitudinal vortex generator is best.Overall,for the radial motion enhancement of particles,the optimum row number of longitudinal vortex are one and two.With the increase of the height of the static bed,the influence of the multi-row longitudinal vortex generator on the radial velocity in the spout region gradually increases,and that on the radial velocity of the particles in the annulus gradually decreases.The smaller the particle diameter and density is,the better the longitudinal vortex enhancement effect is.Numerical simulation is used to check the particle phase flow characteristics of the longitudinal vortex generator.The influence of the particle density and the height of the static bed on the gas-solid two-phase flow in the jet bed is further analyzed.The results show that the particle radial velocity distribution is very consistent with the experimental results.The distribution uniformity of particle volume fraction in bed is negatively correlated with particle density.The lower the height of the static bed,the less the particle processing,the lower the height of the bed,the higher the uniformity of the velocity flow field.