Computational and Experimental Study of Heat Transfer and Hydrodynamics in a 2D Gas−Solid Fluidized Bed Reactor

Abstract

The heat transfer and hydrodynamics of a two-dimensional nonreactive gas-solid fluidized bed reactor were studied experimentally and computationally. A multifluid Eulerian computational model incorporating the kinetic theory for solid particles coupled with the k-ε turbulence model was developed and used to simulate the heat conducting gas-solid flows in a fluidized bed configuration. Momentum exchange coefficients were evaluated using the Syamlal-O'Brien, Gidaspow, and Cao-Ahmadi drag functions. Temperature distributions of different phases in the reactor were also computed. Good agreement was found between the model predictions and the experimentally obtained data for the bed expansion ratio as well as the qualitative gas-solid flow patterns. The simulation and experimental results showed that the gas temperature decreases as it moves upward in the reactor, while the solid particle temperature increases. Pressure drop and temperature distribution predicted by the simulations were in good agreement with the experimental measurements at superficial gas velocities higher than the minimum fluidization velocity. Also, the predicted time-average local voidage profiles were in reasonable agreement with the experimental results. The study showed that the computational model was capable of predicting the heat-transfer and the hydrodynamic behavior of gas-solid fluidized bed flows with reasonable accuracy.

A numerical study on biomass fast pyrolysis process: A comparison between full lumped modeling and hybrid modeling combined with CFD

“…As the bubble rises and grows, the bubble rising velocity increases; consequently, the solid velocity near the bubbles increases as well. In addition, the solid velocity near the walls has greater negative values (Hamzehei et al, 2010). These bubbles and the associated solid flow play an important role in the mixing of solid particles, heat transfer and final fast pyrolysis reaction.…”

CFD Modeling and Simulation of Hydrodynamics in a Fluidized Bed Dryer with Experimental Validation

“…Here v s,w is the particle slip velocity, e ss,w is the restitution coefficient at the wall, and ε s,max is the volume fraction for the particles at maximum packing [19][20][21][22][23][24][25]27]. …”

“…Hamzehei et al [19][20][21][22] investigated unsteady flow and heat transfer in a gas-solid fluidized-bed reactor. Also particle sizes, gas velocity, and drag models effects on hydrodynamics and heat transfer of a nonreactive gas-solid fluidized bed reactor were studied experimentally and computationally.…”

CFD simulation of transient gas to particle heat transfer for fluidized and spouted regimes

“…Recently, Hamzehei and Rahimzadeh [41] and Hamzehei et al [42] studied a bubbling fluidized bed using both experimental and numerical approaches. Comparison of their CFD results with their experimental data showed good agreement for the gas temperature profile.…”