CFD Analysis of Industrial Multi-Stage Impeller in Stirred Tank with Fractal Pattern Baffled and Impeller

This paper presents tool for analysis of CFD adapted for flows in multi-staged stirred vessels with fractal pattern baffled for industrial. In order to develop a good mixing process model for stirred tanks, several way have been investigated by using the computational fluid dynamic. Implementing fractal design into stirred tank’s baffle and impeller are believed to influence the flow characteristic inside the stirred tank. The mixing process will be conduct by using multi-stage stirred tanks. Hence, the study is to simulate a fractal pattern baffled stirred vessels with fractal base of impeller. Four models with a new concept and different design of stirred tank have been introduced and studied. The multi-stages stirred tanks will adapted with fractal base pattern concept. The simulation is carry out by using the standard k-ε turbulence model. The results have been analysis in order to prove that which one of that model is the most effective in mixing. The flows produced in stirred tank are different and relevant with each model. The velocity profiles also give a relevant and quite impressive result by each model. At the end, the results will be examined and compared with each data that use a common type of baffle and impeller design.

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Numerical Simulation of Turbulent Mixing for Dislocated Blades in a Stirred Tank

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.354-355.559 ◽

2011 ◽

Vol 354-355 ◽

pp. 559-563

Author(s):

Lei Shi ◽

Shen Jie Zhou ◽

Feng Ling Yang ◽

Fan Jin Hu

Keyword(s):

Numerical Simulation ◽

Turbulent Mixing ◽

Stirred Tank ◽

Industrial Processes ◽

Mixing Efficiency ◽

Mixing Process ◽

Flow Number ◽

Stirred Tanks ◽

Calculation Results ◽

Better Than

Mixing efficiency is an important parameter in the design of many industrial processes in stirred tanks. In this study, CFD technology was used to simulate the mixing process inside the stirred tank with dislocated blades and standard turbine. Calculations were performed to study the effects of agitator speed and the configuration of impellers on mixing efficiency. The results showed that the flow field in the stirred tank with the dislocated blades is better than the standard turbine, and the flow number of the dislocated blades had been improved while the power number had been reduced. According to calculation results of Wr, we found the mixing efficiency of the dislocated blades had been improved about 4 times than that of standard turbine.

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A Study of Palm Oil-Methanol Mixing in a Stirred Tank Equipped with a Fractal Baffles

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.736.39 ◽

2015 ◽

Vol 736 ◽

pp. 39-44 ◽

Cited By ~ 1

Author(s):

Bukhari Manshoor ◽

Ali Asmayou ◽

Amir Khalid ◽

Izzuddin Zaman

Keyword(s):

Palm Oil ◽

Stirred Tank ◽

Time Interval ◽

Mixing Process ◽

Ansys Fluent ◽

New Approach ◽

Fractal Pattern ◽

Industry Applications ◽

Simulation Results ◽

Slow Mixing

Palm oil and methanol do not form a single phase mixture in transesterification process in stirred tank due to a poor surface contact between them; hence give a relatively slow mixing process of the mixing. Introduction of new baffles in the stirred tank with a fractal pattern due to the fractal shape can give a high turbulent level when a fluid flow through the fractal pattern is the new idea in optimizing the using of the fractal pattern in engineering especially in mixing industries. Hence, in the present study, a new concept of baffles with a fractal design was proposed to enhance a palm oil-methanol mixing in stirred tank. In order to achieve the objective, the simulation of palm oil-methanol mixing was carried out by using ANSYS Fluent software. The simulation was carrying out primarily in the stirred tank equipped with the fractal baffles and the levels of mixing were observed at 60, 120, 180 and 240 seconds after the beginning of introduction of methanol in the stirred tank. An effectiveness of the fractal baffles will be evaluated by determining the Coefficient of Variation (COV). The simulation results also were compared in term of homogeneity level of palm oil-methanol mixing to the normal baffles in order to determine the significant effect of the fractal baffles. Based on the simulation results, the value of COV for the mixing process in the stirred tank equipped with fractal baffles at the selected time interval are 0.066, 0.0436, 0.0326 and 0.0226 respectively. Since the values of COV between 0.01 and 0.05 are a reasonable target for many industry applications, the results for new approach of stirred tank with fractal baffles represent completely homogeneous mixing for the palm oil-methanol simulated in this study. Definitely this new approach of fractal baffles gave better results because of lower number of COV compared to the stirred tank with normal baffles.

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Nanoparticle Precipitation in a T-Mixer: Coupling Experimental and Numerical Investigations of the Fluid Dynamics With the Solid Formation Processes

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2006-98092 ◽

2006 ◽

Author(s):

Johannes Gradl ◽

Florian Schwertfirm ◽

Hans-Christoph Schwarzer ◽

Hans-Joachim Schmid ◽

Michael Manhart ◽

...

Keyword(s):

Flow Field ◽

Fluid Dynamic ◽

Concentration Field ◽

Population Balance ◽

Mixing Process ◽

Image Velocimetry ◽

Modeling Material ◽

Field Information ◽

Set Up ◽

3D Information

Mixing and consequently fluid dynamic is a key parameter to tailor the particle size distribution (PSD) in nanoparticle precipitation. Due to fast and intensive mixing a static T-mixer configuration is capable for synthesizing continuously nanoparticles. The flow and concentration field of the applied mixer is investigated experimentally at different flow rates by Particle Image Velocimetry (PIV) and Laser Induced Fluorescence (LIF). Due to the PIV measurements the flow field in the mixer was characterized qualitatively and the mixing process itself is quantified by the subsequent LIF-measurements. A special feature of the LIF set up is to detect structures in the flow field, which are smaller than the Batchelor length. Thereby a detailed insight into the mixing process in a static T-Mixer is given. In this study a CFD-based approach using Direct Numerical Simulation (DNS) in combination with the solid formation kinetics solving population balance equations (PBE) is applied, using barium sulfate as modeling material. A Lagrangian Particle Tracking strategy is used to couple the flow field information with a micro mixing model and with the classical theory of nucleation. We found that the DNS-PBE approach including macro and micro mixing, combined with the population balance is capable of predicting the full PSD in nanoparticle precipitation for different operating parameters. Additionally to the resulting PSD, this approach delivers a 3D-information about all running subprocesses in the mixer, i.e. supersaturation built-up or nucleation, which is visualized for different process variables.

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Sample selection of prognostics validation test based on multi-stage Wiener process

Proceedings of the Institution of Mechanical Engineers Part O Journal of Risk and Reliability ◽

10.1177/1748006x18805835 ◽

2018 ◽

Vol 233 (4) ◽

pp. 605-614

Author(s):

Zhiao Zhao ◽

Yong Zhang ◽

Guanjun Liu ◽

Jing Qiu

Keyword(s):

Wiener Process ◽

Process Model ◽

Failure Modes ◽

Early Stage ◽

Sample Selection ◽

Degradation Process ◽

Time Interval ◽

Degradation Data ◽

Multi Stage ◽

Selection Of

Sample allocation and selection technology is of great significance in the test plan design of prognostics validation. Considering the existing researches, the importance of prognostics samples of different moments is not considered in the degradation process of a single failure. Normally, prognostics samples are generated under the same time interval mechanism. However, a prognostics system may have low prognostics accuracy because of the small quantity of failure degradation and measurement randomness in the early stage of a failure degradation process. Historical degradation data onto equipment failure modes are collected, and the degradation process model based on the multi-stage Wiener process is established. Based on the multi-stage Wiener process model, we choose four parameters to describe different degradation stages in a degradation process. According to four parameters, the sample selection weight of each degradation stage is calculated and the weight of each degradation stage is used to select prognostics samples. Taking a bearing wear fault of a helicopter transmission device as an example, its degradation process is established and sample selection weights are calculated. According to the sample selection weight of each degradation process, we accomplish the prognostics sample selection of the bearing wear fault. The results show that the prognostics sample selection method proposed in this article has good applicability.

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Modeling evaluation on solid-liquid mixing characteristics in a dislocated guide impeller stirred tank

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2021-0147 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Deyin Gu ◽

Fenghui Zhao ◽

Xingmin Wang ◽

Zuohua Liu

Keyword(s):

Power Consumption ◽

Solid Particle ◽

Particle Diameter ◽

Solid Particles ◽

Stirred Tank ◽

Mixing Process ◽

Solid Holdup ◽

Aperture Ratio ◽

Liquid Mixing ◽

Solid Liquid

Abstract The solid-liquid mixing characteristics in a stirred tank with pitched blade impellers, dislocated impellers, and dislocated guide impellers were investigated through using CFD simulation. The effects of impeller speed, impeller type, aperture ratio, aperture length, solid particle diameter and initial solid holdup on the homogeneity degree in the solid-liquid mixing process were investigated. As expected, the solid particle suspension quality was increased with an increase in impeller speed. The dislocated impeller could reduce the accumulation of solid particles and improve the cloud height compared with pitched blade impeller under the same power consumption. The dislocated guide impeller could enhance the solid particles suspension quality on the basis of dislocated impeller, and the optimum aperture ratio and aperture length of dislocated guide impeller were 12.25% and 7 mm, respectively, in the solid-liquid mixing process. Smaller solid particle diameter and lower initial solid holdup led to higher homogeneity degree of solid-liquid mixing system. The dislocated guide impeller could increase solid particle integrated velocity and enhance turbulent intensity of solid-liquid two-phase compared with pitched blade impeller and dislocated impeller under the same power consumption.

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A sediment-mixing process model of till genesis, using texture and clay mineralogy data from Saginaw lobe (Michigan, USA) tills

Quaternary Research ◽

10.1017/qua.2019.82 ◽

2020 ◽

Vol 94 ◽

pp. 174-194

Author(s):

Randall J. Schaetzl ◽

Christopher Baish ◽

Patrick M. Colgan ◽

Jarrod Knauff ◽

Thomas Bilintoh ◽

...

Keyword(s):

Process Model ◽

Clay Mineralogy ◽

Lacustrine Sediment ◽

Mixing Process ◽

Spatial Approach ◽

Sediment Mixing ◽

Spatial Grouping ◽

Lacustrine Clay ◽

Texture Mode ◽

Bimodal Grain Size

AbstractWe present a sediment-mixing process model of till genesis based on data from surface tills of the Saginaw lobe terrain in lower Michigan. Our research uses a spatial approach to understanding glacial landsystems and till genesis. We sampled calcareous till at 336 upland sites and at 17 sites in lacustrine sediment of the Saginaw Lake plain. The loamy tills have bimodal grain-size curves, with a fine-texture mode near the silt–clay boundary and a sand mode. Spatial grouping analysis suggests that tills can be divided into six groups, each with different textures and clay mineral compositions that vary systematically down-ice. The similarity among groups with respect to the silt–clay mode and clay mineralogy argues for a common origin for the fines—illite-rich lacustrine sediment of the Saginaw Lake plain. Fine-textured sediments were probably entrained, transported, and deposited down-ice as till, which also becomes sandier and enriched in kaolinite, reflecting increasing mixing with shallow sandstone bedrock with distance from the lacustrine clay source. Clayey tills on the flanks of the Saginaw terrain may reflect proglacial ponding against nearby uplands. A process model of progressive down-ice mixing of preexisting fine lake sediments with crushed/abraded sandstone bedrock helps to better explain till textures compared with a purely crushing/abrasion process model.

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Hydrodynamics and Mass Transfer Analysis in BioFlow® Bioreactor Systems

Processes ◽

10.3390/pr8101311 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1311 ◽

Cited By ~ 1

Author(s):

Marian Kordas ◽

Maciej Konopacki ◽

Bartłomiej Grygorcewicz ◽

Adrian Augustyniak ◽

Daniel Musik ◽

...

Keyword(s):

Mass Transfer ◽

Mixing Time ◽

Mass Transfer Rate ◽

Mass Transfer Process ◽

Mixing Process ◽

Stirred Tanks ◽

Mixing Energy ◽

Biotechnological Processes ◽

Liquid Transfer ◽

Mathematical Relationships

Biotechnological processes involving the presence of microorganisms are realized by using various types of stirred tanks or laboratory-scale dual-impeller commercial bioreactor. Hydrodynamics and mass transfer rate are crucial parameters describing the functionality and efficiency of bioreactors. Both parameters strictly depend on mixing applied during bioprocesses conducted in bioreactors. Establishing optimum hydrodynamics conditions for the realized process with microorganisms maximizes the yield of desired products. Therefore, our main objective was to analyze and define the main operational hydrodynamic parameters (including flow field, power consumption, mixing time, and mixing energy) and mass transfer process (in this case, gas–liquid transfer) of two different commercial bioreactors (BioFlo® 115 and BioFlo® 415). The obtained results are allowed using mathematical relationships to describe the analyzed processes that can be used to predict the mixing process and mass transfer ratio in BioFlo® bioreactors. The proposed correlations may be applied for the design of a scaled-up or scaled-down bioreactors.

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CFD simulation of flow patterns in unbaffled stirred tank with CD-6 impeller

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq111130029d ◽

2012 ◽

Vol 18 (4-1) ◽

pp. 535-546 ◽

Cited By ~ 2

Author(s):

Tamphasana Devi ◽

Bimlesh Kumar

Keyword(s):

Numerical Simulations ◽

Cfd Simulation ◽

Flow Patterns ◽

Industrial Applications ◽

Spatial Variations ◽

Stirred Tank ◽

Rushton Turbine ◽

Stirred Vessels

Understanding the flow in stirred vessels can be useful for a wide number of industrial applications. There is a wealth of numerical simulations of stirring vessels with standard impeller such as Rushton turbine and pitch blade turbine. Here, a CFD study has been performed to observe the spatial variations (angular, axial and radial) of hydrodynamics (velocity and turbulence field) in unbaffled stirred tank with Concave-bladed Disc turbine (CD-6) impeller. Three speeds (N=296, 638 & 844.6 rpm) have been considered for this study. The angular variations of hydrodynamics of stirred tank were found very less as compared to axial and radial variations.

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