Effect of Gas Dispersion on Mixing Time of Liquid in an Agitated Vessel under Laminar Flow Condition

2015 ◽  
Vol 48 (6) ◽  
pp. 403-406
Author(s):  
Koji Takahashi ◽  
Chihiro Ashino ◽  
Yasuyuki Takahata
Keyword(s):  
Laminar Flow ◽  
Flow Condition ◽  
Mixing Time ◽  
Gas Dispersion ◽  
Agitated Vessel

scholarly journals CFD simulation of gas-liquid floating particles mixing in an agitated vessel

2017 ◽  
Vol 23 (3) ◽  
pp. 377-389 ◽  
Author(s):  
Liangchao Li ◽  
Bin Xu
Keyword(s):  
Velocity Field ◽  
Cfd Simulation ◽  
Solid Phase ◽  
Fluid Model ◽  
Surface Region ◽  
Operating Conditions ◽  
Gas Dispersion ◽  
Agitated Vessel ◽  
Superficial Gas Velocity ◽  
Floating Particles

Gas dispersion and floating particles suspension in an agitated vessel were studied numerically by using computational fluid dynamics (CFD). The Eulerian multi-fluid model along with standard k-? turbulence model was used in the simulation. A multiple reference frame (MRF) approach was used to solve the impeller rotation. The velocity field, gas and floating particles holdup distributions in the vessel were first obtained, and then, the effects of operating conditions on gas dispersion and solid suspension were investigated. The simulation results show that velocity field of solid phase and gas phase are quite different in the agitated vessel. Floating particles are easy to accumulate in the center of the surface region and the increasing of superficial gas velocity is in favor of floating particles off-surface suspension. With increasing solids loading, the gas dispersion becomes worse, while relative solid holdup distribution changes little. The limitations of the present modeling are discussed and further research in the future is proposed.

scholarly journals Laminar Mixing in Stirred Tank Agitated by an Impeller Inclined

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Koji Takahashi ◽  
Yoshiharu Sugo ◽  
Yasuyuki Takahata ◽  
Hitoshi Sekine ◽  
Masayuki Nakamura
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Mixing Time ◽  
Flow Region ◽  
Experimental Results ◽  
Stirred Tank ◽  
Simulation Methods ◽  
Mixing Performance ◽  
Laminar Mixing ◽  
Numerical Simulation Methods

The mixing performance in a vessel agitated by an impeller that inclined itself, which is considered one of the typical ways to promote mixing performance by the spatial chaotic mixing, has been investigated experimentally and numerically. The mixing time was measured by the decolorization method and it was found that the inclined impeller could reduce mixing time compared to that obtained by the vertically located impeller in laminar flow region. The effect of eccentric position of inclined impeller on mixing time was also studied and a significant reduction of mixing time was observed. To confirm the experimental results, the velocity profiles were calculated numerically and two novel numerical simulation methods were proposed.

Parametric Study of Phase Change Suspension Flow in Microchannels

2003 ◽  
Author(s):  
Y. L. Hao ◽  
Y.-X. Tao
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Phase Change ◽  
Flow Condition ◽  
Computer Code ◽  
Cfd Modeling ◽  
Transfer Coefficients ◽  
Circular Duct ◽  
Heat Transfer Coefficients ◽  
Melting Region

A continuum model is applied to the numerical simulation of the laminar hydrodynamic and heat-transfer characteristics of suspension with phase change material (PCM) particles in a microchannel. The analytical/numerical formulation based on CFD modeling technique, and the computer code is developed. Local wall-to-suspension heat transfer coefficients are calculated by the simultaneous solution of the conservation of mass, momentum and thermal energy equations. By providing detailed information on the local behavior of the wall-to-suspension heat transfer coefficients, preliminary calculations expose that there exists a particle-depleted layer next to the wall under the laminar flow condition. It plays an important role on the heat transfer between the suspension and the wall under the laminar flow condition. The heat transfer coefficient increases and reaches a peak value in the melting region. The benefits on the enhancement of heat transfer and the reduction of wall temperature and mean temperature by employing the MCPCM particle are mainly in the melting region. The preliminary results agree very well with the experimental observations and measurement on the flow and heat transfer of microencapsulated PCM slurry in circular duct. It interprets the observation in the literature where heat transfer between the suspension and the wall is weaker in non-melting region and melted region than that between the pure fluid and the wall for laminar flow conditions.

Hydrodynamics of slug flow in a vertical narrow rectangular channel under laminar flow condition

2014 ◽  
Vol 73 ◽  
pp. 465-477 ◽  
Author(s):  
Yang Wang ◽  
Changqi Yan ◽  
Xiaxin Cao ◽  
Licheng Sun ◽  
Chaoxing Yan ◽  
...  
Keyword(s):  
Laminar Flow ◽  
Flow Condition ◽  
Slug Flow ◽  
Rectangular Channel

ERT Visualization of Gas Dispersion Performance of Aerofoil and Radial Impellers in an Agitated Vessel

2013 ◽  
Vol 64 (5) ◽  
Author(s):  
Mohd Sobri Takriff ◽  
Azmi Ahmad ◽  
Masli Irwan Rosli ◽  
Sadiah Jantan
Keyword(s):  
Real Time ◽  
Research Work ◽  
Projection Algorithm ◽  
Time Data ◽  
Gas Dispersion ◽  
Rushton Turbine ◽  
Agitated Vessel ◽  
Surface Plot ◽  
Reconstruction Software ◽  
Linear Back Projection

The objective of this research work was to determine the gas dispersion performance of an aerofoil impeller and a standard Rushton turbine for gas–liquid mixing an agitated vessel via electrical resistance tomography (ERT) visualization. The experimental work was carried out in a fully baffled 400-mm-diameter agitated vessel that was fitted with four planes of 16 stainless steel electrodes connected to an ITS P2000 ERT system. Agitation was achieved by using a Lightnin Labmaster system mounted on the vessel. The ITS ERT system is equipped with a real-time data acquisition system that has the capability to capture images at up to 20 frames per second. The gas dispersion images were reconstructed using built-in image reconstruction software based on a modified linear back projection algorithm. A Matlab code was also developed to further analyse the gas dispersion by plotting a real-time surface plot from the ERT data. Various gas dispersion conditions such as flooded, transition, and dispersed were successfully visualized and characterized using the ERT technique, and over the range of the experimental works, the standard Rushton turbine was found to be a more efficient than the Lightnin A320 impeller.

Mixing Time in an Agitated Vessel Equipped with Large Impeller

2015 ◽  
Vol 48 (7) ◽  
pp. 513-517 ◽  
Author(s):  
Koji Takahashi ◽  
Naoki Sugawara ◽  
Yasuyuki Takahata
Keyword(s):  
Mixing Time ◽  
Agitated Vessel

Comparative assessment of mixing in compact coiled flow inverters under diffusion free laminar flow condition

2020 ◽  
Vol 159 ◽  
pp. 455-467 ◽  
Author(s):  
Vandana Kumari Jha ◽  
Loveleen Sharma ◽  
Shantanu Roy ◽  
K.D.P. Nigam ◽  
Soubhik Kumar Bhaumik
Keyword(s):  
Laminar Flow ◽  
Flow Condition ◽  
Comparative Assessment
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