scholarly journals Research for a Non-Standard Kenics Static Mixer with an Eccentricity Factor

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1353
Author(s):  
Chenfeng Wang ◽  
Hanyang Liu ◽  
Xiaoxia Yang ◽  
Rijie Wang
Keyword(s):  
Fluid Flow ◽  
Aspect Ratio ◽  
Twist Angle ◽  
Univariate Analysis ◽  
Flow Simulation ◽  
Asymmetric Structure ◽  
Static Mixer ◽  
Static Mixers ◽  
Aspect Ratios ◽  
Symmetric Structure

The Kenics static mixer is one of the most widely studied static mixers, whose structure–function relationship has been studied by varying its aspect ratio and modifying the surface. However, the effect of the symmetric structure of the Kenics static mixer itself on twisting the fluid has been neglected. In order to study how the symmetrical structure of the Kenics static mixer impacts the fluid flow, we changed the center position of elements at twist angle 90° and introduced the eccentricity factor γ. We applied LHS-PLS to study this non-standard Kenics static mixer and obtained the statistical correlations of the aspect ratio, Reynolds number, and eccentricity factor on relative Nusselt number and relative friction factor. We analyzed the results by comparing the PLS model with the univariate analysis, and it was found that the underlying logic of the Kenics static mixer with an asymmetric structure became different. In addition, a non-standard Kenics static mixer with an asymmetric structure was investigated using vortex generation and dissipation through fluid flow simulation. The results demonstrated that the classical symmetric structure has a minor pressure drop, but the backward eccentric one has a higher thermal-hydraulic performance factor. It was found that the nature of the eccentric structure is that two elements with different aspect ratios are being combined at θ=90°, and this articulation leads to non-standard Kenics static mixers with different underlying logic, which finally result in the differences between the PLS model and the univariate analysis.

Numerical Research of Pressure Drop in Kenics Static Mixer

2013 ◽  
Vol 694-697 ◽  
pp. 547-550 ◽  
Author(s):  
Guang Hui Chen ◽  
Zheng Liang Liu
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Twist Angle ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Static Mixer ◽  
Static Mixers ◽  
Numerical Research ◽  
High Reynolds ◽  
The Relationship

The objective of the present work is to characterize and investigate the effect of aspect ratio and twist angle of elements on the pressure drop predictions in Kenics static mixers using three-dimensional CFD approach. Twenty different kinds of Kenics mixers have been characterized. The numerical approach took into account the relationship between pressure drop and aspect ratio and relationship between pressure drop and twist angle at high Reynolds number within the Kenics mixer, which was neglected in previous studies. It is found from the study that the pressure drop is the function of aspect ratio and twist angle with a specified geometry at a certain flow rate.

Analysis of the Pressure Drop of the Horizontal Liquid-Solid Circulation Fluidization Bed with Kenics Static Mixers

2013 ◽  
Vol 291-294 ◽  
pp. 791-794
Author(s):  
Yan Liu ◽  
Shao Feng Zhang ◽  
Jiang Tao Wang
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Aspect Ratio ◽  
Friction Factor ◽  
Static Mixer ◽  
Experiment Data ◽  
Dimensionless Parameters ◽  
Static Mixers ◽  
Dimensionless Pressure ◽  
Dimension Analysis

In order to obtain the pressure drop of the horizontal liquid-solid circulation fluidization bed with Kenics static mixers, experiments were carried out in four Kenics static mixers with different aspect ratio of mixing element(AR) over a range of 30000 to 51000 to get pressure drop data. Dimension analysis revealed that the pressure drop characteristic of the Kenics static mixer can be described by three dimensionless parameters, such as the friction factor, Reynolds number, and aspect ratio of mixing element. According to the experiment data, a new dimensionless pressure drop correlation was developed. The results indicate that the value of Cf becomes constant and has no correlation with the value of Re in fixed AR. The value of Cf was increased with the increase of AR.

Large-Eddy Turbulent Flow Simulation of a KOMAX Static Mixer

2008 ◽  
Author(s):  
Ramin K. Rahmani ◽  
Theo G. Keith ◽  
Anahita Ayasoufi
Keyword(s):  
Turbulent Flow ◽  
Critical Role ◽  
Flow Simulation ◽  
Reynolds Numbers ◽  
Static Mixer ◽  
Viscous Liquids ◽  
Pressure Drops ◽  
Static Mixers ◽  
Eddy Simulation ◽  
Large Eddy

Viscous liquids have to be homogenized in continuous operations in many branches of processing industries; and therefore, fluid mixing plays a critical role in the success or failure of many industrial processes. Consequences of improper mixing include non-reproducible processing conditions and lowered product quality, resulting in the need for more elaborate downstream processes and increased costs. The range of practical flow Reynolds numbers for KOMAX static mixers in industry is usually from moderate values (Re ≈ 0) to very large values (e.g. Re ≈ 5,000,000). However, most of industrial applicants have a very small flow to moderate Reynolds numbers (e.g. Re ≈ 5,000). This paper presents an improved understanding of the turbulent flow pattern for single-phase liquids through the mixer. Large-Eddy Simulation (LES) model is applied to the flow in a KOMAX static mixer to calculate the flow velocities, pressure drops, etc. Using a variety of predictive tools, the mixing results are obtained.

scholarly journals Linear Hydrodynamic Stability of Fluid Flow in Curved Rectangular Ducts: Semi-Analytical Study

2019 ◽  
Vol 35 (5) ◽  
pp. 747-765 ◽  
Author(s):  
H. Nowruzi ◽  
H. Ghassemi ◽  
S. S. Nourazar
Keyword(s):  
Fluid Flow ◽  
Aspect Ratio ◽  
Eigenvalue Problem ◽  
Flow Instability ◽  
Wave Number ◽  
Dean Number ◽  
Analytical Technique ◽  
Dean Flow ◽  
Aspect Ratios ◽  
Analytical Results

ABSTRACTIn the current study, for the first time, a semi-analytical technique is used for solving eigenvalue problem arising from linear hydrodynamics stability of fluid flow through the curved rectangular ducts at different curvature ratios and aspect ratios. To this accomplishment, symmetric disturbances are assumed and the Homotopy perturbation method (HPM) is applied to solve our eigenvalue problem for curvature ratios ranging from 0.01 to 0.8 and aspect ratios ranging from 0.05 to 20. Our semi-analytical results are validated through the existing numerical and experimental data, showing good agreement. The semi-analytical results indicate that, as the curvature ratio increases the critical Dean number (Dnc) is increased and the flow becomes more stable, especially for aspect ratios lower than 1.Moreover, for all intended curvature ratios, irregular behavior in variation of Dnc is detected by an increase in the aspect ratio. So that, the Dnc is decreased when the aspect ratio increases from 0.05 up to 1 and the fluid flow becomes unstable. When the aspect ratio is increased from 1 to 5, it causes to increase the Dnc and fluid flow becomes stable. Furthermore, when the aspect ratio increases from 5 to 20, the Dnc is decreased again. In addition, Dnc and eigenvalues of critical complex wave number corresponding to Dnc for the onset of Dean flow instability is reported under different curvature ratios and aspect ratios.

scholarly journals Experimental studies on hydrodynamic aspects for mixing of non-Newtonian fluids in a Komax static mixer

2020 ◽  
pp. 9-9
Author(s):  
D. Revathi ◽  
K. Saravanan
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Unit Length ◽  
Continuous Process ◽  
Experimental Studies ◽  
Vital Role ◽  
Newtonian Fluids ◽  
Static Mixer ◽  
Static Mixers ◽  
Mixing Performance

Mixing is the degree of homogeneity of two or more phases and it plays a vital role in the quality of the final product. It is conventionally carried out by mechanical agitators or by static mixers. Static mixers are a series of geometric mixing elements fixed within a pipe, which use the energy of the flow stream to create mixing between two or more fluids or to inject metered liquid into a continuous process. The objective of this work is to predict hydrodynamic aspects of the static mixer designed. The mixing performance of Komax static mixer has been determined for the blending of non-Newtonian fluid streams with identical or different rheology by using experimental study. The energy needed for mixing comes from the force created by the liquid due to turbulence and the geometry of the static mixer. Pressure drop in static mixer depend strongly on geometric arrangement of the inserts, properties of fluids to be mixed and flow conditions. Hence pressure drop studies are carried out for different flow rates of fluids with different concentrations of two non-Newtonian fluids. Starch and xanthan gum solutions are used as working fluids. It is observed from the experimental results that the pressure drop per unit length increases as the fluid flow rate increases and the nature of fluid flow varies with the velocity of the fluids.

Fluid-Induced Forces in Pump Liquid Seals With Large Aspect Ratio

2011 ◽  
Author(s):  
Alexandrina Untaroiu ◽  
Vahe Hayrapetian ◽  
Costin D. Untaroiu ◽  
Paul E. Allaire ◽  
Houston G. Wood ◽  
...  
Keyword(s):  
Shear Stress ◽  
Fluid Flow ◽  
Aspect Ratio ◽  
Stokes Equations ◽  
Complex Geometry ◽  
Dynamic Properties ◽  
Fluid Velocity ◽  
Bulk Flow ◽  
Large Aspect Ratio ◽  
Aspect Ratios

The instability due to fluid flow in seals is a known phenomenon that can occur in pumps and compressors as well as in steam turbines. Traditional annular seal models are based on bulk flow theory. While these methods are computationally efficient and can predict dynamic properties fairly well for short seals, they lack accuracy in cases of seals with complex geometry or with large aspect ratios (above 1.0). Unlike the bulk flow models, computational fluid dynamics (CFD) makes no simplifying assumption on the seal geometry, shear stress at the wall, relationship between wall shear stress and mean fluid velocity, or characterization of interfaces between control volumes through empirical friction factors. This paper presents a method to calculate the linearized rotor-dynamic coefficients for a liquid seal with large aspect ratio (balance drum) subjected to incompressible turbulent flow by means of a three dimensional CFD analysis to calculate the fluid-induced forces acting on the rotor. The Reynolds-averaged Navier-Stokes equations for fluid flow are solved by dividing the volume of fluid into a discrete number of points at which unknown variables are computed. As a result, all the details of the flow field, including the fluid forces with potential destabilizing effects, are calculated. A 2nd order curve fit is then used to express the fluid-induced forces in terms of equivalent linearized stiffness, damping, and fluid inertia coefficients.

Heat Transfer Analysis Of Nano-fluid Flow In A Converging Nozzle With Different Aspect Ratios

2017 ◽  
Vol 20 (4) ◽  
pp. 161-167 ◽  
Author(s):  
T. Sathish
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Aspect Ratio ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Heat Transfer Analysis ◽  
Element Analysis ◽  
Frictional Loss ◽  
Nano Fluid ◽  
Aspect Ratios

The study evaluates the nanofluid using finite element analysis with base fluid (water) and seeding particles (Aluminum oxide). This is placed over a convergence channel consisting of varying aspect ratio that are evaluated quantitatively to enhance the heat transfer properties of the nanofluid.We have considered frictional loss characteristics that increases the flow of the fluid with Reynolds numbers varying from 100-2000 is compared.A baseline modeling is established using the methodology analysis for the fluid flow over a rectangular chamber that is designed in the form of a square duct of ratio 1:1. The analysis is carried out over the heat transfer and flow rate characteristics of the nanofluid that converges into the square ducts with different aspect ratio, is analyzed.The concentration of the nano fluid is maintained at the constant rate, which is used for studying the flow rate influence over different aspect ratios. The thermal and flow characteristics is analyzed in such situation and validated against other literatures to check the efficiency in the converging rectangular oxygen free copper channel.The simulation results shows an increase in temperature on the duct out and drop in temperature on the inlet walls of the tube.The pressure changes and shear stress along the walls of the chamber is not much noticed and it is constant throughout the entire chamber.

Large-Eddy Turbulent Flow Simulation of an Industrial Helical Static Mixer

Volume 4 ◽  
2004 ◽  
Author(s):  
Ramin K. Rahmani ◽  
Theo G. Keith ◽  
Anahita Ayasoufi
Keyword(s):  
Turbulent Flow ◽  
Critical Role ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Reynolds Numbers ◽  
Static Mixer ◽  
Static Mixers ◽  
Large Eddy ◽  
Turbulent Models ◽  
Les Model

Viscous liquids have to be homogenized in continuous operations in many branches of processing industries; and therefore, fluid mixing plays a critical role in the success or failure of many industrial processes. Consequences of improper mixing include non-reproducible processing conditions and lowered product quality, resulting in the need for more elaborate downstream purification processes and increased waste disposal costs. The range of practical flow Reynolds numbers for helical static mixers in industry is usually from very small (Re ≈ 0) to moderate values (e.g. Re = 5,000). However, it has been found that the flow regime within helical static mixers is turbulent for relatively low Reynolds numbers, compared to the flow inside a pipe with no mixing elements present. This paper extends previous studies by the authors on the industrial helical static mixer. Its purpose is to present an improved understanding of the turbulent flow pattern for single-phase liquids through the mixer. Three-dimensional finite volume simulations are used to study the performance of the mixer using different turbulent models. Large-Eddy Simulation (LES) model is applied to the flow in an industrial helical static mixer to calculate the flow velocities, pressure drops, etc. Using a variety of predictive tools, the mixing results are obtained. Also, the accuracy and global performance of several different turbulent models are compared against the LES model.

Computation of Fluid-Structure Interaction in a Static Mixer Using MpCCi

2002 ◽  
Author(s):  
Torsten Wintergerste
Keyword(s):  
High Pressure ◽  
Fluid Flow ◽  
Polymer Melt ◽  
Complex Structures ◽  
Loose Coupling ◽  
Static Mixer ◽  
Melt Blending ◽  
Static Mixers ◽  
Structure Interaction ◽  
Coupling Approach

Static mixers are used for the mixing of fluids with different properties like viscosity, density, temperature, etc. The Sulzer SMB mixer is designed for a high pressure drop which is e.g. the case in polymer melt blending. The deformation of the mixer caused by the fluid flow is investigated by the coupling of commercial CFD and FEA codes through a communications library called MpCCI. This loose coupling approach gives the opportunity for calculating the deformation of very complex structures which can be used for an optimization process during the phase of development of new mixers. This paper shows the use of the coupling of the two commercial codes STAR-CD and PERMAS by MpCCI for the investigation of the deformations of a mixer. It demonstrates that the use of coupling allows a more realistic calculation of stresses inside the structure.

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