Influence of different parameters on the tube-to-bed heat transfer coefficient in a gas-solid fluidized bed heat exchanger

Bisognin, Priscilla Corrêa; Bastos, Jaci Carlo Schramm Câmara; Meier, Henry França; Padoin, Natan; Soares, Cíntia

doi:10.1016/j.cep.2019.107693

Cited by 13 publications

(3 citation statements)

References 41 publications

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“…Several aspects of fluid dynamics within the bed influence the heat transfer coefficient correlation, including form, gas distributor design, and particle size distribution. Historically, researchers have commonly utilized the outcomes of prior experiments to develop correlations for heat transport in fluidized beds [34].…”

Section: The Formulation Of a Heat Transfer Correlation For Fluidized...mentioning

confidence: 99%

Nano-Iron Oxide Coating for Enhanced Heat Transfer in Gas–Solid Fluidized Bed Systems

Faraj,

Ali,

Najim

et al. 2024

ChemEngineering

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This study explores using iron oxide coatings on glass beads to improve heat transfer efficiency in fluidized bed reactors. Techniques such as BET surface area analysis, SEM imaging, and X-ray diffraction were used to characterize the coated beads. Results showed the successful creation of a crystalline iron layer on the beads’ surface and increased thermal conductivity, especially at elevated temperatures. The study also quantified the impact of air surface velocity and heating power on the heat transfer coefficient, revealing substantial improvements, especially at higher velocities. It was found that the heat transfer coefficient for 600 µm glass beads increases significantly from 336.4 W/m2·K to 390.3 W/m2·K when the velocity is 0.27 m/s and the heating flux is 125 W. This demonstrates the effectiveness of the iron oxide coating in improving heat transfer. The results of this study emphasize the efficacy of iron oxide coatings in augmenting heat transmission characteristics, particularly in fluidized bed reactor.

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Section: The Formulation Of a Heat Transfer Correlation For Fluidized...mentioning

confidence: 99%

Nano-Iron Oxide Coating for Enhanced Heat Transfer in Gas–Solid Fluidized Bed Systems

Faraj,

Ali,

Najim

et al. 2024

ChemEngineering

View full text Add to dashboard Cite

show abstract

“…In the former few decades, several numerical models were established to simulate the flow of mixed solid fluid, the highly used models are Eulerian-Lagrangian and Eulerian-Eulerian models [1]. Bisognin et al [3] used a combined Experiments Design and CFD techniques to study the heat exchanger of a gas-solid fluidized bed. They investigated the heat transfer coefficient and the variables effected on it.…”

Section: Introductionmentioning

confidence: 99%

Effect of Wall Heat Transfer on the Fluidization Process

Ridha¹,

Al-Azawy²

2021

IJHT

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The fluidized bed and the fluidization process and characteristics were studied in this paper numerically using Computational Fluid Dynamics (CFD) Ansys Fluent 15.0. Constant temperature was applied to both sides of the two-dimensional fluidized bed geometry. The superficial velocity of the working fluid ranged amid (0.08 – 0.5 m/s) and the initial height of the solid particles changed amid (0.05, 0.1, 0.2 m). Aluminum particles and water was used as working materials within the fluidized bed. The model used for the investigations was validated using Ngoh and Lim research results. The results showed that the fluidization head increases as the water inlet superficial velocity increases. As well as when the water inlet superficial velocity increases, the average solid phase temperature increases.

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“…Bisognin et al [75] employed a combination of CFD and design of experiment techniques to examine the influence of various variables on the tube-to-bed heat transfer coefficient in a gas-solid fluidized bed heat exchanger. A 2 5-1 fractional factorial design was utilized to investigate five variables.…”

Section: Literature Reviewmentioning

confidence: 99%

Improvement of hydrodynamics and heat transfer in biomass fluidized bed combustor with immersed tubes using CFD-DEM

Korkerd

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Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) has been extensively utilized for studying hydrodynamics and heat transfer in fluidization processes. This study specifically focuses on improving hydrodynamics and heat transfer in a biomass fluidized bed combustor with immersed tubes. The investigation involves the use of mixed biomass, exploring the effects of biomass types, biomass loading, and blending ratios to propose criteria for selecting suitable biomass fuel for the system. Design parameters related to the immersed tubes, such as the angle between tubes, tube diameters, and distance between tubes, were also considered. A data-driven model was developed based on the CFD-DEM results to predict system parameters. This model offers potential applications in real-time practical engineering without the need for CFD-DEM simulation. The CFD-DEM model was developed for cylindrical biomass and spherical silica sand particles, incorporating an appropriate drag force model. The results showed that the use of mixed biomass with a blending ratio of 1:3 of wood chips to coarse bagasse, with a 5% biomass loading using a ratio of the average equivalent diameter of the biomasses to the equivalent diameter of silica sand of 4.44, was identified as suitable conditions in a general case to obtain the most efficient hydrodynamic results in this study. The criteria for selecting biomass are cylindrical biomass with a greater equivalent diameter than silica sand. Additionally, the proportion of wood chips should be less than that of bagasse. Furthermore, through a 2k factorial design analysis, it was determined that the angle between tubes and tube diameter had the most significant influence on the system behaviors. Moreover, the development of Artificial Neural Network (ANN) models was successful using the simulation dataset, enabling accurate predictions of the mixing index, solid volume fraction, and solid temperature within the system. This study enhances the understanding of hydrodynamics and heat transfer within systems and provides valuable insights for optimizing the design and operation of applications involving mixed biomass and silica sand.

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Influence of different parameters on the tube-to-bed heat transfer coefficient in a gas-solid fluidized bed heat exchanger

Cited by 13 publications

References 41 publications

Nano-Iron Oxide Coating for Enhanced Heat Transfer in Gas–Solid Fluidized Bed Systems

Nano-Iron Oxide Coating for Enhanced Heat Transfer in Gas–Solid Fluidized Bed Systems

Effect of Wall Heat Transfer on the Fluidization Process

Improvement of hydrodynamics and heat transfer in biomass fluidized bed combustor with immersed tubes using CFD-DEM

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