Mass transfer in ducts with transpiring walls

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Abstract

The problem of mass transfer in ducts with transpiring walls is analysed: the concepts of “solvent” and “solute” fluxes are introduced, all possible sign combinations for these fluxes are considered, and relevant examples from membrane processes such as electrodialysis, reverse osmosis and filtration are identified. Besides the dimensionless numbers commonly defined in studying flow and mass transfer problems, new dimensionless quantities appropriate to transpiration problems are introduced, and their limiting values, associated with “drying”, “desalting” and “saturation” conditions, are identified. A simple model predicting the Sherwood number Sh under all possible flux sign combinations is derived from the single simplifying assumption that concentration profiles remain self-similar (so that the Sherwood number based on diffusion only remains unchanged) also under transpiration conditions. The simple model provides not only local values of Sh, but also its axial profiles. Predictions are validated against fully predictive CFD results, not based on the above simplifying assumption, and a good agreement is demonstrated provided the transpiration rate complies with certain limitations, depending on the Schmidt number.
Lingua originaleEnglish
pagine (da-a)1074-1086
Numero di pagine13
RivistaInternational Journal of Heat and Mass Transfer
Volume132
Stato di pubblicazionePublished - 2019

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transpiration
Transpiration
ducts
Ducts
mass transfer
Mass transfer
Fluxes
electrodialysis
reverse osmosis
dimensionless numbers
Salt removal
Schmidt number
Electrodialysis
Reverse osmosis
charge flow devices
profiles
drying
Drying
solutes
Computational fluid dynamics

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes

Cita questo

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title = "Mass transfer in ducts with transpiring walls",
abstract = "The problem of mass transfer in ducts with transpiring walls is analysed: the concepts of “solvent” and “solute” fluxes are introduced, all possible sign combinations for these fluxes are considered, and relevant examples from membrane processes such as electrodialysis, reverse osmosis and filtration are identified. Besides the dimensionless numbers commonly defined in studying flow and mass transfer problems, new dimensionless quantities appropriate to transpiration problems are introduced, and their limiting values, associated with “drying”, “desalting” and “saturation” conditions, are identified. A simple model predicting the Sherwood number Sh under all possible flux sign combinations is derived from the single simplifying assumption that concentration profiles remain self-similar (so that the Sherwood number based on diffusion only remains unchanged) also under transpiration conditions. The simple model provides not only local values of Sh, but also its axial profiles. Predictions are validated against fully predictive CFD results, not based on the above simplifying assumption, and a good agreement is demonstrated provided the transpiration rate complies with certain limitations, depending on the Schmidt number.",
author = "Michele Ciofalo and Micale, {Giorgio Domenico Maria} and {La Cerva}, {Mariagiorgia Floriana} and Luigi Gurreri and {Di Liberto}, Massimiliano and Luigi Scelsi",
year = "2019",
language = "English",
volume = "132",
pages = "1074--1086",
journal = "International Journal of Heat and Mass Transfer",
issn = "0017-9310",
publisher = "Elsevier Limited",

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TY - JOUR

T1 - Mass transfer in ducts with transpiring walls

AU - Ciofalo, Michele

AU - Micale, Giorgio Domenico Maria

AU - La Cerva, Mariagiorgia Floriana

AU - Gurreri, Luigi

AU - Di Liberto, Massimiliano

AU - Scelsi, Luigi

PY - 2019

Y1 - 2019

N2 - The problem of mass transfer in ducts with transpiring walls is analysed: the concepts of “solvent” and “solute” fluxes are introduced, all possible sign combinations for these fluxes are considered, and relevant examples from membrane processes such as electrodialysis, reverse osmosis and filtration are identified. Besides the dimensionless numbers commonly defined in studying flow and mass transfer problems, new dimensionless quantities appropriate to transpiration problems are introduced, and their limiting values, associated with “drying”, “desalting” and “saturation” conditions, are identified. A simple model predicting the Sherwood number Sh under all possible flux sign combinations is derived from the single simplifying assumption that concentration profiles remain self-similar (so that the Sherwood number based on diffusion only remains unchanged) also under transpiration conditions. The simple model provides not only local values of Sh, but also its axial profiles. Predictions are validated against fully predictive CFD results, not based on the above simplifying assumption, and a good agreement is demonstrated provided the transpiration rate complies with certain limitations, depending on the Schmidt number.

AB - The problem of mass transfer in ducts with transpiring walls is analysed: the concepts of “solvent” and “solute” fluxes are introduced, all possible sign combinations for these fluxes are considered, and relevant examples from membrane processes such as electrodialysis, reverse osmosis and filtration are identified. Besides the dimensionless numbers commonly defined in studying flow and mass transfer problems, new dimensionless quantities appropriate to transpiration problems are introduced, and their limiting values, associated with “drying”, “desalting” and “saturation” conditions, are identified. A simple model predicting the Sherwood number Sh under all possible flux sign combinations is derived from the single simplifying assumption that concentration profiles remain self-similar (so that the Sherwood number based on diffusion only remains unchanged) also under transpiration conditions. The simple model provides not only local values of Sh, but also its axial profiles. Predictions are validated against fully predictive CFD results, not based on the above simplifying assumption, and a good agreement is demonstrated provided the transpiration rate complies with certain limitations, depending on the Schmidt number.

UR - http://hdl.handle.net/10447/334284

M3 - Article

VL - 132

SP - 1074

EP - 1086

JO - International Journal of Heat and Mass Transfer

JF - International Journal of Heat and Mass Transfer

SN - 0017-9310

ER -