The effect of symmetrical perforated holes on the turbulent heat transfer in the static mixer with modified Kenics segments

Meng, Hang; Zhu, Guangxue; Yu, Yanfang; Wang, Zongyong; Wu, Jianhua

doi:10.1016/j.ijheatmasstransfer.2016.03.110

Cited by 34 publications

(12 citation statements)

References 34 publications

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“…A constant heat flux of 10,000 w/m 2 was applied to the tube wall, and since the temperature rise was not significant, the changes in density and viscosity due to temperature were negligible. In Meng [12], it has been demonstrated that the mass and heat transfer properties are stabilized after passing through the 12 section cell. To reduce the computational effort while the effect of geometric parameters is being examined, after the flow field has been fully developed, periodic boundary conditions are used at the inlet and outlet.…”

Section: Computational Fluid Dynamicsmentioning

confidence: 99%

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

et al. 2021

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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.

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Section: Computational Fluid Dynamicsmentioning

confidence: 99%

“…Kenics static mixers, as one of the classic types of static mixers, have the advantages of their unique structure and easy manufacturing. Its structure-function relationship has been extensively studied for many years [11][12][13][14]. The element of the Kenics static mixer is obtained by 180 • reversing two ends of a metal blade.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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“…The importance of structural properties of blade shape design and manufacturing, in practice, may highly affect the pressure drop in the mixer Heniche et al (2005). Other designs of static element geometry were developed ranging from open to close, depends on the conditions and the requirements of the mixing system Ghanem et al (2014), Meng et al (2016b), Soman and Madhuranthakam (2017), Haddadi et al (2020).…”

Section: Armentioning

confidence: 99%

“…There are small regions of great stretching; higher mixing efficiency is obtained by TKSM and FKSM than the DKSM and KSM. In the same context of internal geometry modification in the static mixer, Meng et al (2016b) used CFD tools to investigate the performance of perforated blades of a modified Kenics static mixer in the turbulent flow. The impact of holes, size, spacing and the number of mixing elements on the overall performance of heat transfer were analyzed.…”

Section: Armentioning

confidence: 99%

Effect of Geometry Design on Mixing Performance of Newtonian Fluids using Helical Overlapped Mixer Elements in Kenics Static Mixer

Talhaoui

Draoui

Youcefi

2021

JAFM

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The laminar flow pattern and mixing behavior of incompressible Newtonian fluids in different modified mixer configurations were numerically investigated using Computational Fluid Dynamics (CFD) simulations in the range of Re=0.15-100. The governing equations were solved by ANSYS Fluent 14 using the second-order finite volume method (FVM) and the SIMPLE algorithm scheme. The computational model is assessed by comparing the predicted pressure drop results to empirical correlations in the literature. The effects of incorporated helical overlapped mixer elements and the diameter aspect ratio (C) on the mixing efficiency for different mixer geometries were examined and evaluated by characteristics measures of Intensity of Segregation (IOS), pressure drop, extensional efficiency, and G-factor. The performance of new modified mixers is evaluated via comparison with the standard industrial Kenics static mixer. The static mixers with modified internal geometry achieved fast mixing and better mixing quality than the Kenics mixer. Besides, an increase in diameter aspect ratio C benefited from a decrease in pressure drop within the static. The modified mixer: C=1.5 was found to have the highest mixing efficiency, concerning short mixing length with marginally higher pressure drop than the other mixers. In contrast, the mixer: C=2 is the most efficient based on low pressure drop and energy requirement with slightly greater mixing length.

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“…[6][7][8][9] A CFD study by Liu et al 8 on the effect of geometry on laminar mixing in SMX static mixers showed that a combination of mixing element with 10 crossbars followed by the mixing element with eight crossbars shows the best mixing quality. Meng et al 10 used a perforated Kenics mixer to simulate forced convective heat transfer of water under uniform tube wall temperature and concluded that the Nusselt number and the friction factor are not sensitive to the increasing perforated spacing within a given perforated diameter.…”

Section: Introductionmentioning

confidence: 99%

Design and characterization of a Low‐pressure‐drop static mixer

2019

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in Wiley Online Library (wileyonlinelibrary.com)Four-blade static mixer was designed for inline mixing of Newtonian fluids at Reynolds numbers from 700 to 6800. The mixer consists of four equally spaced blades mounted on cylindrical housing with 45 rotation relative to the circumference. It was tested in three different compartments of 6, 8, and 10 mixing elements; each element rotated 45 relative to the adjacent one. Multipoint sampling was used to measure concentration downstream the mixer. The mixing quality was measured by the coefficient of variance (CoV). The CoV decreases as the energy input per unit mass increases. This effect is more pronounced when the number of mixing elements increases. For the case of 10 mixing elements, a good mixing performance (typically more than 95% mixedness or CoV < 0.05) achieved, although a marginally good mixing performance could also be achieved by eight mixing elements. The friction factors were correlated as f = C 1 /Re + C 2 /Re n with an average deviation of AE10% from experimental data. Furthermore, experimental friction factors were compared with existing models. For a wide range of Reynolds numbers, the friction factors are apparently smaller than those from SMV, KMX, and baffle-type static mixers. Figure 11. Comparison of friction factor data with other models.

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The effect of symmetrical perforated holes on the turbulent heat transfer in the static mixer with modified Kenics segments

Cited by 34 publications

References 34 publications

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

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

Effect of Geometry Design on Mixing Performance of Newtonian Fluids using Helical Overlapped Mixer Elements in Kenics Static Mixer

Design and characterization of a Low‐pressure‐drop static mixer

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