Numerical evaluation of turbulent flow structures in a stirred tank with a Rushton turbine based on scale-adaptive simulation

2018 ◽  
Vol 170 ◽  
pp. 236-248 ◽  
Author(s):  
Ali Zamiri ◽  
Jin Taek Chung
Keyword(s):  
Turbulent Flow ◽  
Numerical Evaluation ◽  
Stirred Tank ◽  
Flow Structures ◽  
Rushton Turbine ◽  
Adaptive Simulation

Large-eddy simulation of turbulent flow in an unbaffled stirred tank driven by a Rushton turbine

2005 ◽  
Vol 60 (8-9) ◽  
pp. 2303-2316 ◽  
Author(s):  
Raul Alcamo ◽  
Giorgio Micale ◽  
Franco Grisafi ◽  
Alberto Brucato ◽  
Michele Ciofalo
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Stirred Tank ◽  
Rushton Turbine ◽  
Eddy Simulation ◽  
Large Eddy

Experimental Study and Detached Eddy Simulation of the Macro-Instability in an Eccentric Stirred Tank

2011 ◽  
Vol 66-68 ◽  
pp. 20-26 ◽  
Author(s):  
Feng Ling Yang ◽  
Shen Jie Zhou ◽  
Gui Chao Wang
Keyword(s):  
Reynolds Number ◽  
Turbulent Flow ◽  
Simulation Method ◽  
Dominant Frequency ◽  
Diameter Ratio ◽  
Stirred Tank ◽  
Detached Eddy Simulation ◽  
Rushton Turbine ◽  
Eddy Simulation ◽  
Tank Diameter

The turbulent flow in stirred tank is highly complicated and anisotropic, especially when the macro-instability (MI) are involved. In this work, the numerical simulation method of the eccentric agitation was established based on the detached eddy simulation (DES) model to study the MI in an eccentric stirred tank. The turbulent flow in the eccentrically located Rushton turbine stirred tank was numerically investigated. The rotation of the impeller was simulated by the transient sliding mesh (SM) method. The effect of eccentricity, impeller Reynolds number and impeller-tank diameter ratio were studied in order to quantify the MI frequency. PIV experiments were performed to validate the DES results and frequency analyses were applied to the obtained time series of the velocity recordings. It was found that the flow field in eccentrically stirred tank are highly unsteady and is subject to MI with varying period less than 10 blade passage period. Good agreements have been found between the DES and PIV results, both indicate that the dominant frequency of MI increases linearly with the Reynolds number, increases with the impeller-tank diameter ratio and decreases with the eccentricity. According to the agreements between the experimental and simulation results, it can be concluded that the combination of DES and SM is suitable for the prediction of the MI phenomenon in stirred tanks.

FORCED CONVECTION BASED HEAT TRANSFER ANALYSIS OF SPHERICAL DIMPLE AND PROTRUSION SURFACE IN TURBULENT FLOW

2017 ◽  
Vol 41 (5) ◽  
pp. 771-786 ◽  
Author(s):  
Ashif Perwez ◽  
Shreyak Shende ◽  
Rakesh Kumar
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Vortex Flow ◽  
Rectangular Channel ◽  
Heat Transfer Analysis ◽  
Flow Structures ◽  
Transfer Enhancement ◽  
Heat Transfer Augmentation ◽  
Thermal Boundary Conditions

An experimental and numerical investigation is performed to study the effect of dimple and protrusion geometry on the heat transfer enhancement and the friction factor of surfaces with dimples and protrusions subjected to turbulent flow. The parameters used to compare the spherical dimples and protrusions are Nusselt Number, friction factor, and flow pattern. These parameters are obtained for a Reynolds number of 10500-60900. The spherical dimple results showed the greater heat transfer, which is about 6.97% higher and pressure loss which is 5.07% lower than the spherical protrusion. The realistic heat transfer augmentation capabilities of channels with dimples and protrusions can be studied from the experimental results. The comparison is made with respect to the smooth rectangular channel under the same flow and thermal boundary conditions. The numerical analysis is performed which shows the different vortex flow structures of the spherical dimples and protrusions channel.

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