Particle Scale Simulation of Heat Transfer in Fluid Bed Reactors

Zhou, Zongyan; Hou, Qinfu; Yu, Aibing

doi:10.5772/14072

Cited by 4 publications

(2 citation statements)

References 92 publications

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“…Since the temperature gradient of the sand particles at various heights is almost the same, in this study, the solid phase can be considered as lumped rather than inter-particle. Due to the low emissivity of gas, it is also possible to ignore gas radiation [35]. Therefore, other than heat loss from the walls of the bed, the heat transfer from the hot solid particles to the air is the main mechanism for the discharging process.…”

Section: Key Performance Indicatorsmentioning

confidence: 99%

A Combined Experimental and Numerical Thermo-Hydrodynamic Investigation of High-Temperature Fluidized-Bed Thermal Energy Storage

2022

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The present research describes the design, analysis, and modeling of an air-granular particle fluidized-bed system with dimensions of 0.08 m × 0.4 m × 0.08 m. The hydrodynamic and thermal experiments are designed to verify the numerical model previously created for this purpose. The gas-solid two-phase flow is described using a three-dimensional, two-fluid model based on the Eulerian–Eulerian method. The experiment is conducted, and the numerical model is updated for the new geometry while maintaining the solution parameters. Silica sand and sintered bauxite particles are employed in both experimental and numerical investigations to examine the behaviors of these particles. The hydrodynamic validity of the numerical model is established by the use of experimental findings for pressure drop and bed expansion ratio. The thermal tests are conducted with 585 K hot sand, and the temperature distribution in the bed is measured using K-type thermocouples and compared with the simulation data. Both the hydrodynamical and thermal experimental data appear to agree with the conclusions of the computational analyses. The validated model is then used to mimic the performance of the bed at elevated temperatures. The performance indicators are discussed and calculated for 973 K, demonstrating that as the temperature rises, the system efficiency increases.

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Section: Key Performance Indicatorsmentioning

confidence: 99%

A Combined Experimental and Numerical Thermo-Hydrodynamic Investigation of High-Temperature Fluidized-Bed Thermal Energy Storage

2022

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“…When considering the heat transfer in a gas-solid flow, the total heat flux will be comprised of contributions from conductive, convective, and radiative mechanisms. However, when thermal temperatures within a system are ≲ 700 K, the radiative mechanism is often neglected since it does not significantly contribute to the overall heat transfer 7,23 . Further…”

Section: Introductionmentioning

confidence: 99%

Indirect conduction in gas–solids systems: Static vs. Dynamic effects

Lattanzi

Hrenya

2017

AIChE Journal

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Conductive mechanisms play an integral role in the transfer of heat through dense gas-solid systems. In particular, the conduction occurring through a thin layer of fluid between the solids (indirect) can become the primary mode for heat transfer within gas-solid systems. However, attempts to evaluate the effect of surface roughness and fluid lens thickness (theoretical inputs) on indirect conduction have been restricted to static, single-particle cases. By contrast, here we quantify these effects for dynamic, multi-particle systems using a non-dimensional, average heat transfer coefficient that is obtained via techniques commonly employed by classic kinetic theory.Analytical predictions for the impact of theoretical inputs on indirect conduction are compared to outputs from computational fluid dynamics -discrete element method simulations. The analytical predictions are in agreement with simulations and show that indirect conduction in static systems is most sensitive to surface roughness, while dynamic systems are sensitive to the fluid lens thickness.

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