Heat and mass transfer in the condensing flow of steam through an absorbing fibrous medium

Le, Cuong; Ly, N.G.; Postle, R.

doi:10.1016/0017-9310(94)00139-m

Cited by 48 publications

(37 citation statements)

References 14 publications

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“…The implemented model describes the transient diffusion of heat and mass through hygroscopic materials, following the general governing equations given by Le et al [34,35], Barker et al [36], and Gibson [37]. The model considers that the textile contains three elements (fibres, air with water vapour and liquid water), and the major simplifying assumptions are: (1) the textile material is considered a homogeneous medium with mentioned three elements (i.e.…”

Section: Model Assumptions and Equationsmentioning

confidence: 99%

“…Thus the mass transfer area corresponds to the total area of the fibres [34]. The water condensation rate ( _ m cond ) is therefore proportional to the specific surface area of the fibre (a s ) and to the difference between the vapour concentration in the gas (q v ), and vapour concentration near the surface where condensation occurs (q sat v ),…”

Section: Appendix a Mass Rates Of Condensation And Evaporation Of Watermentioning

confidence: 99%

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Effects of clothing and fibres properties on the heat and mass transport, for different body heat/sweat releases

Neves

Campos

Mayor

2017

Applied Thermal Engineering

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Section: Model Assumptions and Equationsmentioning

confidence: 99%

Section: Appendix a Mass Rates Of Condensation And Evaporation Of Watermentioning

confidence: 99%

Effects of clothing and fibres properties on the heat and mass transport, for different body heat/sweat releases

Neves

Campos

Mayor

2017

Applied Thermal Engineering

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“…Several works in literature report studies on the heat and mass transport in textile structures [1][2][3][4][5][6][7][8][9]. Le et al [1] and Gibson and Charmchi [9] used volume-averaging techniques to address the interaction between heat and mass transfer, and track concentration and temperature fronts as moisture is transported through hygroscopic materials.…”

Section: Introductionmentioning

confidence: 99%

“…Le et al [1] and Gibson and Charmchi [9] used volume-averaging techniques to address the interaction between heat and mass transfer, and track concentration and temperature fronts as moisture is transported through hygroscopic materials. Barker et al [3] used a similar approach to analyse the role of moisture transport in the protection offered by firefighter garments exposed to high intensity thermal radiation.…”

Section: Introductionmentioning

confidence: 99%

“…However, the measurement of some of these parameters is not straightforward and requires access to complex/expensive experimental facilities [1,9]. Furthermore, in some of the available literature [1][2][3][4][5][6][7][8][9], it is not entirely clear how some parameters are determined (e.g. porosity, tortuosity) which renders difficult the comparison of results from different authors and may hamper a faster adoption of numerical approaches in clothing development activities.…”

Section: Introductionmentioning

confidence: 99%

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On the determination of parameters required for numerical studies of heat and mass transfer through textiles – Methodologies and experimental procedures

Neves

Campos

Mayor

2015

International Journal of Heat and Mass Transfer

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a b s t r a c tThe aim of this study was to develop methodologies and experimental procedures to determine textile parameters required in numerical approaches of heat and mass transfer through textiles. Privileging techniques usually available in textile/clothing laboratories, experimental approaches were defined that allow to estimate all required parameters, while taking into consideration water presence in the fibres and hence the effect of fibres hygroscopic properties. Numerical models usually require values of textile thickness, fibre fraction, and tortuosity, as well as knowledge of the boundary conditions, e.g. convective heat and mass transfer coefficients. To calculate these parameters, thickness, weight, and volume of textile samples were measured, whereas convective and textile evaporative resistances were determined by indirect measurements. Results were obtained for four distinct textile samples (made of wool, cotton, and a mixture of materials), of different hydrophilic nature. When the obtained parameters were incorporated in a numerical model and numerical predictions of temperature and humidity were compared with experimental data obtained during measurements of fabric evaporative resistance, it was shown that the predictions were accurate; this lends support to the developed methods and approaches.Since an uncertainty in the measured parameters can compromise the accuracy of numerical predictions, a sensitivity analysis was conducted to study the influence of deviations in the model input parameters and of assumptions regarding water presence in the fibres, on the predictions of heat and mass transfer rates. The results show that a deviation in textile weight and thickness as well as the assumption of no water retained in fibres during their characterisation, have a significant effect on the predicted heat transfer and water distribution over time. Moreover, a deviation in the total evaporative resistance, convective evaporative resistance, and sorption rate factor has great influence on the heat flux obtained in the initial period of testing.

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Study of the effect of wind speed on evaporation from soil through integrated modeling of the atmospheric boundary layer and shallow subsurface

et al. 2014

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In an effort to develop methods based on integrating the subsurface to the atmospheric boundary layer to estimate evaporation, we developed a model based on the coupling of Navier-Stokes free flow and Darcy flow in porous medium. The model was tested using experimental data to study the effect of wind speed on evaporation. The model consists of the coupled equations of mass conservation for two-phase flow in porous medium with single-phase flow in the free-flow domain under nonisothermal, nonequilibrium phase change conditions. In this model, the evaporation rate and soil surface temperature and relative humidity at the interface come directly from the integrated model output. To experimentally validate numerical results, we developed a unique test system consisting of a wind tunnel interfaced with a soil tank instrumented with a network of sensors to measure soil-water variables. Results demonstrated that, by using this coupling approach, it is possible to predict the different stages of the drying process with good accuracy. Increasing the wind speed increases the first stage evaporation rate and decreases the transition time between two evaporative stages (soil water flow to vapor diffusion controlled) at low velocity values; then, at high wind speeds the evaporation rate becomes less dependent on the wind speed. On the contrary, the impact of wind speed on second stage evaporation (diffusion-dominant stage) is not significant. We found that the thermal and solute dispersion in free-flow systems has a significant influence on drying processes from porous media and should be taken into account.

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Heat and mass transfer in the condensing flow of steam through an absorbing fibrous medium

Cited by 48 publications

References 14 publications

Effects of clothing and fibres properties on the heat and mass transport, for different body heat/sweat releases

Effects of clothing and fibres properties on the heat and mass transport, for different body heat/sweat releases

On the determination of parameters required for numerical studies of heat and mass transfer through textiles – Methodologies and experimental procedures

Study of the effect of wind speed on evaporation from soil through integrated modeling of the atmospheric boundary layer and shallow subsurface

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