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CFD prediction of flow, heat and mass transfer in woven spacer-filled channels for membrane processes
- Publication Year :
- 2021
- Publisher :
- Elsevier Ltd, 2021.
-
Abstract
- Flow and heat or mass transfer in channels provided with woven spacers made up of mutually orthogonal filaments were studied by Computational Fluid Dynamics. The problem addressed was the combined effect of the parameters that characterize the process: pitch to height ratio P/H (2, 3 and 4), flow attack angle θ (0, 7, 15, 20, 30, 40 and 45°) and Reynolds number Re (from ~1 to ~4000). The Prandtl number was 4.33, representative of water at ~40°C, while the Schmidt number was 600, representative of NaCl solutions. Simulations were performed by the finite volume code Ansys CFX™ 18.1 using very fine grids of ~6 to ~14 million volumes. For Re > ~400, the SST turbulence model was used to predict flow and heat transfer; no simulations of mass transfer were performed in the turbulent regime because the resolution of the diffusive sublayer would have required a prohibitive number of grid points. Results were validated against experimental data, including results obtained by Liquid Crystal Thermography and Digital Image Processing. The flow attack angle θ = 45° was the most effective for mixing (higher Nusselt number, Nu, and Sherwood number, Sh) and caused lower values of friction coefficient (f). In the range investigated, increasing the pitch to height ratio P/H caused Nu, Sh and f all to decrease. Therefore, the highest values of Sh and Nu were provided by the configuration P/H = 2, θ = 45°. Compared with non-woven spacers, woven spacers provided a better mixing, especially at intermediate values of Re, but at the expenses of higher pressure drops.
- Subjects :
- Settore ING-IND/26 - Teoria Dello Sviluppo Dei Processi Chimici
Materials science
020209 energy
Prandtl number
02 engineering and technology
Computational fluid dynamics
Sherwood number
symbols.namesake
Temperature polarization
Mass transfer
0202 electrical engineering, electronic engineering, information engineering
Pressure drop
Concentration polarization
Woven spacer
Settore ING-IND/19 - Impianti Nucleari
Fluid Flow and Transfer Processes
Turbulence
Mechanical Engineering
Schmidt number
Reynolds number
Mechanics
021001 nanoscience & nanotechnology
Condensed Matter Physics
Nusselt number
SST turbulence model
Heat transfer
symbols
0210 nano-technology
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....af4d75cb135a4684e294938be69e98fb