Momentum, Mass and Heat Transfer in Single-Phase Turbulent Flow

Thakre, Shirish; Joshi, Jyeshtharaj B.

doi:10.1515/revce.2002.18.2-3.83

Cited by 21 publications

(23 citation statements)

References 97 publications

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“…Furthermore, the turbulent kinetic energy is higher in case of bubble column with the perforated plate sparger (except z / D = 1), indicating the high level of turbulence in this case. The profiles of turbulent kinetic energy do not show any peak near the wall as generally observed in case of turbulent pipe flows. , In our work, the access to the near wall region was limited up to r / R ≈ 0.95 due to extreme curvature effects. However, the experimental observations from the literature also indicate that the turbulent kinetic energy does not show any peak near the wall. , Obviously, the pipe flow and bubble column are two different hydrodynamic systems.…”

Section: Resultssupporting

confidence: 66%

Laser Doppler Anemometer Measurements in Bubble Column: Effect of Sparger

Bhole

Roy

Joshi

2006

Ind. Eng. Chem. Res.

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Measurements of flow pattern in a 150 mm i.d. bubble column were carried out using a laser doppler anemometer (LDA) in a forward scatter mode. A superficial gas velocity of 20 mm/s was used in all the experiments. Two different spargers (perforated plate and porous plate) were employed. The liquid flow starts developing from the sparger where non-uniformities in the gas sparging exist. From z/D ≥ 2 (z = axial location; D = column diameter), the fully developed axial liquid velocity profiles are seen. The radial variation of mean axial velocity shows gross liquid circulation in the column. Circulation velocities are smaller for the bubble column with porous plate sparger mainly due to the fact that the mean bubble size is small and the gas distribution is relatively uniform over the column cross-section. The difference in the hydrodynamic behavior with two different spargers is also apparent from the profiles of the turbulent kinetic energy and Reynolds stress measured from the velocity−time series.

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Section: Resultssupporting

confidence: 66%

Laser Doppler Anemometer Measurements in Bubble Column: Effect of Sparger

Bhole

Roy

Joshi

2006

Ind. Eng. Chem. Res.

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“…3 clearly shows the impact of the layer thickness near the pipe wall on the prediction of the changing flow behavior. Thus, one can conclude that the rate of deformation of the fluid layer increases for laminar flow and decreases in turbulent flow [19]. Now, the present work is given a good agreement when the shear stress remains slightly constant at the pipe wall layer.…”

Section: Comparison Between Laminar and Turbulent Single Flow Withsupporting

confidence: 73%

Study of the Behaviours of Single-Phase Turbulent Flow at Low to Moderate Reynolds Numbers Through a Vertical Pipe. Part I: 2d Counters Analysis

2020

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This study presents a model to investigate the behavior of the single-phase turbulent flow at low to moderate Reynolds number of water through the vertical pipe through (2D) contour analysis. The model constructed based on governing equations of an incompressible Reynolds Average Navier-Stokes (RANS) model with (k-ε) method to observe the parametric determinations such as velocity profile, static pressure profile, turbulent kinetic energy consumption, and turbulence shear wall flows. The water is used with three velocities values obtained of (0.087, 0.105, and 0.123 m/s) to represent turbulent flow under low to moderate Reynolds number of the pipe geometry of (1 m) length with a (50.8 mm) inner diameter. The water motion behavior inside the pipe shows by using [COMSOL Multiphysics 5.4 and FLUENT 16.1] Software. It is concluded that the single-phase laminar flow of a low velocity, but obtained a higher shearing force; while the turbulent flow of higher fluid velocity but obtained the rate of dissipation of shearing force is lower than that for laminar flow. The entrance mixing length is affected directly with pattern of fluid flow. At any increasing in fluid velocity, the entrance mixing length is increase too, due to of fluid kinetic viscosity changes. The results presented the trends of parametric determinations variation through the (2D) counters analysis of the numerical model. When fluid velocity increased, the shearing force affected directly on the layer near-wall pipe. This leads to static pressure decreases with an increase in fluid velocities. While the momentum changed could be played interaction rules between the fluid layers near the wall pipe with inner pipe wall. Finally, the agreement between present results with the previous study of [1] is satisfied with the trend

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“…Capability of CFD to predict heat transfer coefficient in simple geometries such as pipeline reactor has been carefully analysed by Thakre and Joshi (2002). They have used standard k − ε model, low Reynolds number k − ε model, and the Reynolds stress model (RSM) for the prediction of heat transfer coefficient in a single‐phase fully developed turbulent pipe flow.…”

Section: Introductionmentioning

confidence: 99%

CFD simulation of stirred tanks: Comparison of turbulence models. Part I: Radial flow impellers

et al. 2011

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A critical review of the published literature regarding the computational fluid dynamics (CFD) modelling of single-phase turbulent flow in stirred tank reactors is presented. In this part of review, CFD simulations of radial flow impellers (mainly disc turbine (DT)) in a fully baffled vessel operating in a turbulent regime have been presented. Simulated results obtained with different impeller modelling approaches (impeller boundary condition, multiple reference frame, computational snap shot and the sliding mesh approaches) and different turbulence models (standard k − ε model, RNG k − ε model, the Reynolds stress model (RSM) and large eddy simulation) have been compared with the in-house laser Doppler anemometry (LDA) experimental data. In addition, recently proposed modifications to the standard k − ε models were also evaluated. The model predictions (of all the mean velocities, turbulent kinetic energy and its dissipation rate) have been compared with the experimental measurements at various locations in the tank. A discussion is presented to highlight strengths and weaknesses of currently used CFD models. A preliminary analysis of sensitivity of modelling assumptions in the k − ε models and RSM has been carried out using LES database. The quantitative comparison of exact and modelled turbulence production, transport and dissipation terms has highlighted the reasons behind the partial success of various modifications of standard k − ε model as well as RSM. The volume integral of predicted energy dissipation rate is compared with the energy input rate. Based on these results, suggestions have been made for the future work in this area.Nous présentons un examen critique de la littérature concernant la modélisation de la dynamique des fluides numérique (DFN) de l'écoulement turbulentà une phase dans les réacteursà cuve agitée. Dans cette partie de l'examen, nous présentons les simulations de DFN de turbinesà ecoulement radial (principalement des turbinesà disque (TD)) dans un réservoir entièrement cloisonné effectuées dans un régime turbulent. Les résultats des simulations obtenus grâceà différentes approches de modélisation des turbines (couche limite turbulente, méthode des référentiels multiples, snap-shot de modélisation numérique, maillage glissant) età différents modèles de turbulence (modèle standard k-e, modèle RNG k-e, modèle aux tensions de Reynolds et simulation des grandeséchelles) ontété comparés aux données expérimentales internes d'allocation de Dirichlet latente (ADL). De plus, les modifications des modèles standards k-e récemment proposées ontégalementétéévaluées. Les prédictions du modèle (de toutes les vitesses moyennes, de l'énergie cinétique turbulente et de son taux de dissipation) ontété comparées aux données expérimentales relevéesà différents endroits de la cuve. Une discussion présente les points forts et les points faibles des modèles de DFN actuellement utilisés. Une analyse préliminaire de la sensibilité des hypothèses de modélisation liées aux modèles k-e et RSM aété menée en utilis...

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Momentum, Mass and Heat Transfer in Single-Phase Turbulent Flow

Cited by 21 publications

References 97 publications

Laser Doppler Anemometer Measurements in Bubble Column: Effect of Sparger

Laser Doppler Anemometer Measurements in Bubble Column: Effect of Sparger

Study of the Behaviours of Single-Phase Turbulent Flow at Low to Moderate Reynolds Numbers Through a Vertical Pipe. Part I: 2d Counters Analysis

CFD simulation of stirred tanks: Comparison of turbulence models. Part I: Radial flow impellers

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