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.

1.
Henry
,
P. S. H.
,
1939
, “
Diffusion in Absorbing Media
,”
Proc. R. Soc. London, Ser. A
,
171A
, pp.
215
241
.
2.
Nordan
,
P.
, and
David
,
H. G.
,
1967
, “
Coupled Diffusion of Moisture and Heat in Hygroscopic Textile Mafariah
,”
Int. J. Heat Mass Transf.
,
10
, pp.
853
866
.
3.
Li
,
Y.
, and
Holcombe
,
B. V.
,
1992
, “
A Two Stage Sorption Model of the Coupled Diffusion of Moisture and Heat in Wool Fabrics
,”
Text. Res. J.
,
62
(
4
), pp.
211
217
.
4.
Farnworth
,
B.
,
1986
, “
A Numerical Model of Combined Diffusion of Heat and Water Vapor Through Clothing
,”
Textile Res. Inst.
,
56
, pp.
653
655
.
5.
Jones
,
B. W.
, and
Ogawa
,
Y.
,
1993
, “
Transient Interaction Between the Human and the Thermal Environment
,”
ASHRAE Trans.
,
98
, Part 1, pp.
189
195
.
6.
Minkowycz
,
W. J.
,
Haji-Sheikh
,
A.
, and
Vafai
,
K.
,
1999
, “
On Departure From Local Thermal Equilibrium in Porous Media Due to a Rapidly Changing Heat Source: The Sparrow Number
,”
Int. J. Heat Mass Transf.
,
42
, pp.
3373
3385
.
7.
Gibson, P. 1996, “Governing Equations for Multiphase Heat and Mass Transfer in Hydroscopic Porous Media With Applications to Clothing Materials,” Technical Report NATICK/TR-95/004 by United States Army Natick Research, pp. 105; 115–117.
8.
Gibson
,
P.
,
Kendrick
,
C.
,
Rivin
,
D.
,
Sicuranza
,
L.
, and
Charmchi
,
M.
, 1995, “An Automated Water Vapor Diffusion Test Method for Fabrics, Laminates, and Films,” Journal of Coated Fabrics, 24.
9.
Gibson, P., and Charmchi, M., 1996, “Convective and Diffusive Energy and Mass Transfer in Hygroscopic Porous Textile Materials,” Proceedings of the 1996 International Congress & Exposition, ASME Winter Annual Meeting, No. 96-WA/HT-27, Atlanta, GA, November 17–22.
10.
Gibson
,
P.
, and
Charmchi
,
M.
,
1997
, “
The Use of Volume-Averaging Techniques to Predict Temperature Transients Due to Water Vapor Sorption in Hygroscopic Porous Polymer Materials
,”
J. Appl. Polym. Sci.
,
64
, pp.
493
505
.
11.
Gibson
,
P.
, and
Charmchi
,
M.
,
1997
, “
Coupled Heat and Mass Transfer Through Hygroscopic Porous Materials—Application to Clothing Layers
,”
J. of the Society of Fiber Science and Technology, Japan
,
35
, pp.
183
194
.
12.
Harter, K. L., Spivak, S. M., and Vigo, T. L., 1981, “Applications of the Trace Gas Technique in Clothing Comfort.” Textile Research, 51, pp. 345–355.
13.
Lotens, W., 1993, “Heat Transfer from Humans Wearing Clothing,” Doctoral thesis, published by TNO Institute for Perception, Soesterberg, The Netherlands, pp. 34–37.
14.
Holman, J. P. 1997, Heat Transfer, McGraw-Hill, 8th ed., New York, p. 488, Ch. 8.
15.
Zhao J., 1995, “Computer Modeling for Estimation of Effect of Walking on Clothing Insulation,” M. S. thesis, Kansas State University, Manhattan, KS.
16.
Mortan, W. E., and Hearle, L. W., 1975, Physical Properties of Textile Fibers, Heinemann, London.
17.
ASHRAE Handbook of Fundamentals, 1997, American Society of Heating, Refrigerating and Air conditioning Engineers, Atlanta.
18.
Oohori
,
T.
,
Brglund
,
L. G.
, and
Gagge
,
A. P.
,
1985
, “
Comparison of Current Two Parameters Indices of Vapor Permeation of Clothing—As Factors Governing Thermal Equilibrium and Human Comfort
,”
ASHRAE Trans.
,
90
, Part II, pp.
85
101
.
19.
Hyland
,
R. W.
, and
Wexler
,
A.
,
1983
, “
Formulations for the Thermodynamic Properties of the Saturated Phases of H2O From 173.15 K to 473.15 K
,”
ASHRAE Trans.
,
89
, pp.
500
519
.
20.
Walpole, R. E., and Meyers, R. 1985, Probability and Statistics for Engineers and Scientists, Third Edition, Collier Macmillan, New York, p. 347.
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