Experimental determination of the convective heat and mass transfer coefficients for wood drying

2000 ◽  
Vol 34 (3) ◽  
pp. 253-276 ◽  
Author(s):  
Carl Tremblay ◽  
Alain Cloutier ◽  
Yves Fortin
Keyword(s):  
Mass Transfer ◽  
Experimental Determination ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Wood Drying ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients

Empirical Evaluation of Convective Heat and Moisture Transport Coefficients in Porous Cotton Medium

2002 ◽  
Vol 124 (3) ◽  
pp. 530-537 ◽  
Author(s):  
Kamel Ghali ◽  
Nesreen Ghaddar ◽  
Byron Jones
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Convective Heat ◽  
Transport Coefficients ◽  
Model Parameters ◽  
Moisture Uptake ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Air Penetration ◽  
Heat And Moisture

The air penetration within a porous clothing system on a moving human being is an important physical process that considerably affects the heat and moisture resistance of the textile material. This effect of the coupled convection heat and mass exchange within the clothing system is experimentally investigated and theoretically modeled to determine the heat and mass transfer coefficients between the air penetrating the void space and the solid fiber as a function of the velocity of penetrating air. Experiments were conducted inside environmentally controlled chambers to measure the transient moisture uptake of untreated cotton fabric samples as well as the outer fabric temperature using an infrared pyrometer. The moisture uptake was conducted at three different volumetric flow rates of 0.0067, 0.018 and 0.045 m3/sec/m2 of fabric area to represent airflow penetrations that could result from slow, medium, and vigorous walking, respectively. The theoretical analysis is based on a two-node adsorption model of the fibrous medium. A set of four coupled differential equations were derived describing time-dependent convective heat and mass transfer between the penetrating air and the solid fiber in terms of relevant unknown transport coefficients. The unknown model parameters were adjusted to fit the experimental data. The outer heat and mass transfer coefficients were found to increase with the air penetration flow rate.

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