On the hydrodynamics of a pseudo two-dimensional two-zone gas-solid fluidized bed

Sarbanha, Ali Akbar; Movahedirad, Salman; Ehsani, Mehran

doi:10.1016/j.cej.2018.06.067

Cited by 18 publications

(5 citation statements)

References 61 publications

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“…The complex hydrodynamics of the fluidized bed by a gas flow is described by disordered mixing of solid particles and the formation of gas bubbles, that is confirmed in [25][26][27][28][29]. The effect on the fluid dynamics of a fluidized bed of various parameters was studied: gas injection time into the bed, gas flow velocity and bubbling regime [25], bubble dynamics during nonspherical particles fluidization [26], continuous injection of the central air jet into the bed [27], and features of the pseudo-two-dimensional two-zone gas-solid fluidized bed [28], from the features of solid particles and gas bubbles [29]. Researchers also paid attention to the study of the interphase heat transfer intensity between particles and the gas flow [30] and heat transfer to heat exchange surfaces located in the layer [31][32][33][34].…”

Section: Literature Reviewmentioning

confidence: 74%

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

et al. 2021

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The article deals with the theoretical description and experimental study of the hydrodynamic and heat transfer properties regarding the operation of multistage gravitational devices of the fluidized bed with inclined perforated shelves. The peculiarities of the work and the implementation field of the multistage shelf units are described. A theoretical model to define the solubilizer’s velocity above the perforation holes, in the above-shelf space of the device and in the outloading gap, as well as the residence time of the dispersed phase at the stage (perforated shelf contact) of the device is presented. The results of experimental studies regarding the influence, made by the structural parameters of the perforated shelf contacts, on the distribution pattern of single-phase and gas-dispersed flows in the workspace of the device, on the intensity of interphase heat transfer are presented. The conditions to create active hydrodynamic operating modes of multistage gravitational shelf devices, which provide higher efficiency of heat-mass transfer processes, and with lower gas consumption and hydraulic resistance compared to typical fluidized bed devices, are proved. Peculiarities regarding the implementation of heat-mass transfer processes in multistage devices are described using heat treatment and drying processes as examples.

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Section: Literature Reviewmentioning

confidence: 74%

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

et al. 2021

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“…In the present study, digital image analysis (DIA), which was developed in our previous studies, [ 56–58 ] was employed to determine the real size of the microdroplets. As can be seen in Figure 8B, using an edge detection algorithm, the diameter of microdroplets was obtained to be

318 μm

.…”

Section: Resultsmentioning

confidence: 99%

Computational fluid dynamic study of polycaprolactone nanoparticles precipitation in a co‐flow capillary micro‐tube

2022

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Polycaprolactone nanoparticles (NPs) were produced in the co‐flow glass capillary device with 250μm tip dimension. NPs size was 990 nm for continuous phase velocity, and uc=0.05m/s and 426 nm for uc=0.2m/s. The droplet formation process in the co‐flow microchannel was also simulated using computational fluid dynamic (CFD). Employing a digital image analysis technique, a cut‐off value of 0.81 for the dispersed phase volume fraction was proposed for the determination of droplet size. A scenario was expressed for NP formation from micro‐droplets. Moreover, after conducting 27 CFD simulations, a dimensionless exponential form correlation was proposed for droplet size estimation. In this generalized map, there were three distinct regions based on the relative capillary numbers of continuous to dispersed phases. It was revealed that at a constant dispersed phase velocity, by increasing the continuous phase velocity, more small NPs are formed. The results show that the ratio of micro‐droplets to NPs size was between 735 and 755.

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“…Given the need to rectify the mean velocity profile of the emulsion phase due to the impact of particles within the bubbles, the pioneering work of Laverman et al merging PIV and DIA methods is worth highlighting. Over the past decade, PIV-DIA coupling has been effectively used to study various fluidized bed configurations, including membrane, two-zone/sectional, − and high-temperature/pressure fluidized beds . Here, the experimental technique is implemented for the first time in connection with floating fluidized beds.…”

Section: Methodsmentioning

confidence: 99%

Solids Mixing in Marinized Bubbling Fluidized Beds: Gas Distribution Study

Sarbanha

Larachi

Taghavi

2023

Ind. Eng. Chem. Res.

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Marinized bubbling fluidized beds hold promise for reducing CO 2 , NO X , and SO X in ship exhaust gases, but their use at sea is hampered by a limited understanding of the influence of sea waves on hydrodynamics, heat transfer, and efficiency. To address this gap, this study used direct visualization techniques to investigate the solids mixing and hydrodynamics of bubbling fluidized beds under different gas distribution patterns in pseudo-2D vertical, inclined, and rolling beds. Digital Image Analysis (DIA) was used to determine the Lacey mixing index and the local void fraction, while Particle Image Velocimetry (PIV) was used to capture the particle velocity fields. Additionally, the effects of tilt angles and oscillation parameters of the nonvertical beds were compared with the conventional straight bubbling fluidized bed unit. The uniform inlet distribution of the fluidizing agent was compared with a variety of convex feed distributions at the bed entrance to correct for the negative effects of static/dynamic deviations from bed verticality necessary for optimal operation of bubbling fluidized bed reactors in marine environments.

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On the hydrodynamics of a pseudo two-dimensional two-zone gas-solid fluidized bed

Cited by 18 publications

References 61 publications

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation

Computational fluid dynamic study of polycaprolactone nanoparticles precipitation in a co‐flow capillary micro‐tube

Solids Mixing in Marinized Bubbling Fluidized Beds: Gas Distribution Study

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