Impact of Internals on the Heat-Transfer Coefficient in a Bubble Column

Abdulmohsin, Rahman S.; Al‐Dahhan, Muthanna H.

doi:10.1021/ie2018096

Cited by 21 publications

(8 citation statements)

References 30 publications

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“…The heat transfer probe technique has been used to determine the local heat transfer coefficient in several multiphase flow systems, such as gas-solid fluidized beds, bubble columns, and other heat transfer systems [19][20][21][22][23][24][25]. In these works, the measured heat flux and surface temperature obtained from the heat transfer probe were used to determine the local heat transfer coefficient and its local variations, such as axial and radial profiles.…”

Section: Advanced Heat Transfer Probe Techniquementioning

confidence: 99%

Flow Regimes in Gas‐Solid Fluidized Beds via Micro‐Foil Heat Flux Sensor

2021

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The flow regime transitions in a gas-solid fluidized bed were studied for the first time using a micro-foil heat flux sensor. The time series of heat flux signals was analyzed by statistical and state space methods. The experimental measurements were performed in a lab-scale gas-solid fluidization column. Four different flow regimes, i.e., fixed-bed flow regime, bubbling-flow regime, slugging-flow regime, and turbulent-flow regime, and three intermediate transition velocities, i.e., minimum fluidizing velocity or minimum bubbling velocity, minimum slugging velocity, and minimum turbulent velocity, were successfully identified. The method based on the analysis of heat flux sensor measurements allowed to determine accurately the different flow regimes and the transition velocities.

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Section: Advanced Heat Transfer Probe Techniquementioning

confidence: 99%

Flow Regimes in Gas‐Solid Fluidized Beds via Micro‐Foil Heat Flux Sensor

2021

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“…Even though this reactor is used in alotof industrial applications, few studies have focused on the effect of a bundle of HETs on hydrodynamic, heat, and mass transfer rates [13]- [19]. In addition, very little researchers have investigated the influence of a bundle of HETs on heat transfer in the BC reactor [20]- [22]. Therefore, there is a requirement to investigate further the influence of the presence of bundle of the cooling tube on heat transfer to predict better the thermal performance of such kind reactor toward designing an efficient reactor for conducting high exothermic reactions.…”

Section: Introductionmentioning

confidence: 99%

Effect of a Triangular Configuration of Heat Exchanging Tubes on Local Heat Transfer Coefficient in Bubble Column Reactor

Alzamily¹,

Sultan²,

Abdulrahmn³

2022

IJOGR

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The effect of a triangular configuration of heat exchanging tubes (HETs) on the instantaneous and local heat transfer coefficient (LHTC) has been investigated and quantified in an air-water bubble column (BC) utilising an advanced heat transfer technique. The bundle of heat exchange tubes was designed to cover 25% of the column's cross-sectional area (CSA) to simulate the heat exchanger tubes used in the industrial Fischer Tropsch (FT) process. The local heat flux, surface temperature, bulk temperature, and heat transfer coefficient (HTC) were investigated instantaneously in a Plexiglass BC under a wide range of superficial gas velocity (5-45 cm/s). The obtained results reveal that the presence of a bundle of (HETs) and their arrangement effect the (HTC) in the bubble column, where unsymmetrical profiles for (HTC) were obtained with triangular tube pitch arrangement. Additionally, steeper (HTC) profiles notice were when the triangular tube pitch arrangement was utilized. High (HTC) values were obtained at the core region of the column relative to the wall region under all the studied operating conditions. It was discovered that the local and (HTC) increase as superficial gas velocity increases despite the fact that the bubble column is heavily packed with a bundle of (HETs). The rise in HTCs was higher at the core than at the wall region of the column. For example, at a superficial gas velocity of 45 cm/s and at an axial height of 65 cm (Z/D=5), compared to the wall, the HTC in the core of the column increased by 131 %.

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“…In the past years, many researchers have engaged in investigations on the bubble dynamics in two-phase flows, aiming to enhance the heat- and mass-transfer coefficients or the reaction rate in energy, biology, and chemistry engineering , by controlling the interfacial area between the bubble and the liquid phase. Therefore, exploring the characteristics of bubble behaviors in two-phase flows and finding an optimal way to design the corresponding equipment with high performance is always of importance and interest.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Bubbly Flow Using Partially Averaged Navier–Stokes Simulation and a Path Oscillation Model in the Euler–Lagrange Approach

Zhou

Zhao

et al. 2021

Ind. Eng. Chem. Res.

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Large bubbles always undergo asymmetric paths due to the wake instability, which was rarely considered in the simulation of bubbly flow in complex flow systems such as bubble columns. Here, we propose a bubble path oscillation model considering the zigzag lateral motion caused by the periodic vortex shedding, which is added into the rectilinear bubble motion model in the Lagrange frame. This model is further adopted to simulate the flow of 4 mm bubbles with 680 < Re < 1000 in bubble columns, with the liquid flow predicted by the partially averaged Navier−Stokes model in the Euler frame. A parameter analysis is conducted by comparing the simulation results with the existing experimental data to determine the optimal oscillation amplitude of the path. The effects of oscillation amplitude on the bubble distribution, gas holdup, and flow field are further discussed. Our findings may contribute to the fundamental understanding and accurate simulation of bubbly flow.

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Impact of Internals on the Heat-Transfer Coefficient in a Bubble Column

Cited by 21 publications

References 30 publications

Flow Regimes in Gas‐Solid Fluidized Beds via Micro‐Foil Heat Flux Sensor

Flow Regimes in Gas‐Solid Fluidized Beds via Micro‐Foil Heat Flux Sensor

Effect of a Triangular Configuration of Heat Exchanging Tubes on Local Heat Transfer Coefficient in Bubble Column Reactor

Numerical Simulation of Bubbly Flow Using Partially Averaged Navier–Stokes Simulation and a Path Oscillation Model in the Euler–Lagrange Approach

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