Influence of the Velocity,Local Position,and Relative Humidity of Moist Air on the Convective Mass Transfer Coefficient in a Rectangular Tunnel — Theory and Experiments
Restricted accessResearch articleFirst published online October, 2008
Influence of the Velocity,Local Position,and Relative Humidity of Moist Air on the Convective Mass Transfer Coefficient in a Rectangular Tunnel — Theory and Experiments
This paper explores the effect of the relative humidity (RH) of moist air as well as velocity on the convective mass transfer coefficients (CMTC) at different positions. Experiments determined the local mass transfer coefficients of three water samples mounted in line with the bottom wind tunnel surface. The experiments were carried out at a temperature of 20°C, relative humidities of 30, 50, and 70%, and velocities between 0.1 and 5m/s. The experimental data show that the convective mass transfer coefficient is a function of velocity, the RH of the air and the local position. The experimental results are compared to expressions for the convective mass coefficients from the literature.
Ashrae (2005). Mass Transfer/Psychometrics, In: Handbook of Fundamentals, Chaps 5/6, American Society of Heating, Refrigerating and Air conditioning Engineers, Atlanta, USA, pp. 5.1-5.14 and pp. 6.1-6.17.
2.
Carrier, E.T. (1921). The Theory of Atmospheric Evaporation - with Special Reference to Compartment Dryers, J. Ind. Eng. Chem., 13: 432-438.
3.
Derome, D. (2004). Experimental Determination of the Convective Mass Transfer Coefficient, Presented in IEA, ECBCS, Annex 41, Zurich, Switzerland.
4.
Grausse, P., Bacon, G. and Langlais, C. (1985). Experimental and Theoretical Study of Simultaneous Heat and Moisture Transfer in a Fibrous Insulant, Journal of Thermal Insulation, 9: 46-67.
5.
Hinchley, J.W. and Himus, G.W. (1924). Evaporation in Currents Air, Trans. Inst. Chem. Eng., 2: 57-64.
6.
Hedegaard, L.M., Rode, C. and Peuhkuri, R. (2005). Effect of Airflow Velocity on Moisture Exchange at Surfaces, Presented in IEA, ECBCS, Annex 41 , Trondheim, Norway.
7.
Hagentoft, C.E. (2001). Chap. 14, Transfer Mechanisms, In: Introduction to Building Physics, Studentlitteratur, Lund, Sweden.
8.
Incropera, F.P. and deWitt, D.P. (2002). Chap. 7, External Flow, In: Fundamentals of Heat and Mass Transfer, 3rd edn, pp. 385-466, John Wiley and Sons, USA.
9.
Iskra, C. and Simonson, C. (2005). Effect of Air Humidity on the Convective Mass Transfer Coefficient in a Rectangular Duct, Presented in IEA, ECBCS, Annex 41, Kyoto, Japan.
10.
Jacobsen, S. and Aarseth, L.I. (1999). Effect of Wind on Drying from Wet Porous Building Materials Surfaces - A Simple Model in Steady State, Journal of Materials and Structures, 32: 38-44.
11.
Jason, A.C. (1958) A Study of Evaporation and Diffusion Processes in the Drying of Fish Muscle, in Fundamental Aspects of Dehydration of Foodstuffs , Soc. Chem. Ind. (London) pp. 103-135.
12.
Jürges, W. (1924). Der Wärmeubergang an einer ebenenWand. Beizh. Z. Gesundh. Ing.1(19).
13.
Kakac, S., Shah, R.K. and Aung, W. (1987). Handbook of Single-Phase Convective Heat Transfer , John Wiley & Sons, USA.
14.
Kays, W.M. and Crawford, M.E. (1993). Chaps 10 and 13, In: Layer, Convective Heat and Mass Transfer, 3rd edn, pp. 159-191 and 225-309, McGraw-Hill , USA.
15.
Keey, R. (1972). Chap. 6, Evaporation and Humidification, In: Drying Principles and Practice, Pergamon Press , USA, pp. 149-177.
16.
Lurie, M. and Michailoff, N. (1936). Evaporation from Free Water Surface, Ind. Eng. Chem., 28: 345-349.
17.
Mason, E.A. and Monchick, L. (1965). Survey of the Equation of the State and Transport Properties of Moist Gases. In: Wexler, A. and Wildhack, W.A. (eds), Humidity And Moisture Measurement and Control in Science and Industry , Vol. 3, Reinhold, USA, pp. 257-272.
18.
Mills, A.F. (1995). Chap. 4, Convection and Fundamental and Correlations, Mass Transfer, In: Heat and Mass Transfer, Richard D. Irwin , USA, pp. 243-370.
19.
Panovski, S. (1993). Extols, Units, and Symbols [Velicini Edinici i Oznaki], National and University Library ``Kliment Ohridski'' , Skopje, Macedonia.
20.
Schlichting, H. and Kestin, J. (1968). Chap 2, Outline of Boundary Layer Theory, Boundary-Layer Theory, McGraw-Hill, USA, pp. 24-36.
21.
Time, B., Kvande, T., Terjesen, K. and Sæter, Ø. (2004). Moisture Transport in Mineral Buildings Material - Material Properties [Fukttransport i mineralske bygningsmaterialer - materialegenskaper] , Building Research InstituteOslo , Norway.
22.
Wadsö , L. (1993). Chap. 5, Surface Mass Transfer Coefficients for Wood, Studies of Water Vapor Transport and Sorption in Wood, Building Materials, PhD Dissertation, Lund University, Sweden, pp. 57-72.
23.
White, F.M. (1999). Chap. 7, Flow Past Immersed Bodies, Fluid Mechanics , McGraw-Hill, USA, pp. 449-520.
