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Abstract
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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Experimental and Numerical Study on Flow Resistance and Bubble Transport in a Helical Static Mixer. ENERGIES 2020. [DOI: 10.3390/en13051228] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Flow resistance and bubble transport in a helical static mixer were studied experimentally and numerically. The inline mixer increases the volume fraction of gas in liquids by breaking bubbles into smaller sizes with a micrometer size in the flow experiments. The gas–liquid flow was simulated by a combination of computational fluid dynamics and Taylor expansion methods of moments. The friction factor of the helical static mixer is much smaller than that of the Kenics static mixers. The pressure drop increases with the Reynolds number, and the increment is larger when the Reynolds number is higher. The equidistant pressure drop increases with the argument of Reynolds number, and increases when the pitch decreases from upstream to downstream. The energy expenditure increases significantly when the variable-pitch coefficient is too small. The bubble geometric mean diameter decreases and the geometric standard deviation increases when the gas–liquid fluid flows through the mixer. The variable pitch structure enhances the bubble breakup effectively. The change of the bubble size decreases with the argument of the Reynolds number. The effect of the mixer has a limitation on breaking the bubbles.
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Yadav S, Sahu SK. Effect of Helical Surface Disc Turbulators on Heat Transfer and Friction Factor Characteristics in the Annuli of a Double‐Pipe Heat Exchanger. Chem Eng Technol 2019. [DOI: 10.1002/ceat.201800251] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Saurabh Yadav
- Indian Institute of Technology IndoreDiscipline of Mechanical Engineering Khandwa Road, Simrol 453552 Madhya Pradesh India
| | - Santosh K. Sahu
- Indian Institute of Technology IndoreDiscipline of Mechanical Engineering Khandwa Road, Simrol 453552 Madhya Pradesh India
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Cu-water nanofluid flow and heat transfer in a heat exchanger tube equipped with cross-cut twisted tape. POWDER TECHNOL 2018. [DOI: 10.1016/j.powtec.2018.08.087] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Maradiya C, Vadher J, Agarwal R. The heat transfer enhancement techniques and their Thermal Performance Factor. BENI-SUEF UNIVERSITY JOURNAL OF BASIC AND APPLIED SCIENCES 2018. [DOI: 10.1016/j.bjbas.2017.10.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Meng H, Jiang X, Yu Y, Wang Z, Wu J. Laminar flow and chaotic advection mixing performance in a static mixer with perforated helical segments. KOREAN J CHEM ENG 2017. [DOI: 10.1007/s11814-017-0035-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Hasabnis NS, Totlani KA, Ranade VV. Heat transfer and mixing in flow through pinched pipe. CAN J CHEM ENG 2015. [DOI: 10.1002/cjce.22275] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Nilesh S. Hasabnis
- Industrial Flow Modeling Group; Chemical Engineering and Process Development Division; National Chemical Laboratory; Pune 411008 India
| | - Kartik A. Totlani
- Industrial Flow Modeling Group; Chemical Engineering and Process Development Division; National Chemical Laboratory; Pune 411008 India
| | - Vivek V. Ranade
- Industrial Flow Modeling Group; Chemical Engineering and Process Development Division; National Chemical Laboratory; Pune 411008 India
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Bae Y, Kim SH, Seo JK, Kim YI. Numerical Analysis of Thermal Development of Laminar Flow in a Concentric Multilayer Annulus. Chem Eng Technol 2013. [DOI: 10.1002/ceat.201300528] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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