Abstract
A novel integral multi-jet spout-fluidized bed (IMJSFB) is designed so as to reduce the dead zone at the bottom of the annulus and omit auxiliary equipment for bypass fluidizing air. The gas–solid flow behavior in the IMJSFB was numerically simulated using an Eulerian–Eulerian two-fluid model. A number of slits (4) were formed on the cone side of the cylindrical spouted bed to form an auxiliary multi-jet structure, which can create spoiler effects on the boundary of the pyramidal. The distributions of particle velocity and concentration in the IMJSFB were obtained by numerical simulation. The CFD results show that, compared with the conventional spouted beds, the IMJSFB structure can effectively enhance the particle’s velocity in the annulus of the spouted bed (especially in destroying flow dead zone at the annulus). The enhanced particle motion significantly decreases the volume fraction of the boundary layer on the cone. The particle concentration and velocity distribution along the radial direction become more uniform, and the decrease in value of the coefficient of variation (CV) of the particles’ velocity is 22.9% in IMJSFB. The turbulent kinetic energy of the gas phase can be significantly enhanced and the strengthening effect on the turbulent kinetic energy of the gas remains good with the increase of the bed height.
Highlights
Spouted beds are gas-particle contactors which provide a means of good mixing and circulation for particles of relatively large size and wide size distribution
Wu et al (2018a, b) compared mixing behaviors of gas and particle phases in three types of spouted beds: without disturbance units, with a pair of balls and with a pair of longitudinal vortex generators (LVGs). They found that the radial velocity and granular temperature of the particle phase in the spouted bed can be promoted significantly by a longitudinal vortex. They numerically investigated the influence of row number of longitudinal vortex generators on gas–solid flow behavior in spouted beds
The main objective of the present paper is to study the improvement of gas–solid radial mixing in the integral multi-jet spout-fluidized bed without air supplied auxiliary equipment
Summary
Spouted beds are gas-particle contactors which provide a means of good mixing and circulation for particles of relatively large size and wide size distribution. Kiani et al (2017) experimentally investigated the mixing and segregation of binary mixtures of particles with different sizes and densities in a pseudo2D spouted bed They found that the segregation of solid particles and the time to equilibrium both decreased when the air velocity increased to a magnitude much larger than the minimum spouting velocity, and the axial segregation increased with the diameter ratio of the particles. Bizhaem and Tabrizi (2018) experimentally and numerically studied gas–solid flow behavior in a pulsed fluidized bed They investigated the effect of pulsating flow with frequencies from 1 to 10 Hz for particle sizes of Geldart B and A/B group with varying particle densities. Saidi and Tabrizi (2018) numerically studied influences of the fluidizing and spouting pulsation on particle motion in spout-fluid beds using Navier–Stokes equations for the gas phase coupled with the discrete element method. Estiati et al (2019) experimentally investigated the effect of the geometry and configuration of both confiner and draft tube on article entrainment, operating pressure drop, operating air flow rate and maximum cycle time
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
