Document Type : Research Article

Authors

1 Department of Mechanical Engineering, University of Isfahan, Isfahan, Iran

2 Department of Mechanical Engineering, Shahrekord University, Shahrekord, Iran

Abstract

This paper deals with numerical study of semi-finite incompressible flow of air over two blocks with different heights in the presence of a condensing-source, dispensing- contaminant in the flow, in both steady and unsteady states. The numerical solution of governing PDE equations are constructed by a finite-volume method applied on structured grid arrangement. The effects of air flow velocity, contaminant source length and position, and the blocks height ratio on the concentration distribution, the mass transfer level and the time of transportation are studied. The results indicate that by increasing the inflow Reynolds number, the amount of contamination reaching the blocks and also the amount remaining between them decrease, while the mass transfer rate increases. It is shown that the closer the contaminant source to the blocks, the higher the mean concentration accumulating between the two blocks. It is also found that increasing the blocks height ratio makes an ascending trend to the time for the arrival of contaminant to the blocks walls, though the slopes of time-lines are different for each case.

Keywords

1.     Boum, G.B.N., Martemianov, S. and Alemany, A., "Computational study of laminar flow and mass  transfer a surface-mounted obstacle", International Journal of Heat and Mass Transfer, Vol. 42, No. 15, (1999), 2849-2861.
2.     Hancu, S.A.L., Ghinda, T.A., Ma, L.C., Lesnic, D.B. and Ingham, D.B.B., "Numerical modelling and experimental investigation of the fluid flow and contaminant dispersion in a channel", International Journal of Heat and Mass Transfer, Vol. 45, No. 13, (2002), 2707–2718.
3.     Hayashia, T., Ishizub, Y., Katoa, S., Murakamia, S., "CFD analysis on characteristics of contaminated indoor air ventilation and its application in the evaluation of the effects of contaminant inhalation by a human occupant", Journal of Building and Environment, Vol. 37, No. 3, (2002), 219–230.
4.     Gadgil, A.J., Lobscheid, C., Abadie, M.O. and Finlayson, E.U., "Indoor pollutant mixing time in an isothermal closed room: an investigation using CFD", Journal of Atmospheric Environment, Vol. 37, (2003), 5577–5586.
5.     Kaya, A., Aydin, O. and Dincer, I., "Experimental and numerical investigation of heat and mass transfer during drying of Hayward kiwi fruits, Actinidia Deliciosa Planch", Journal of Food Engineering, Vol. 88, No. 3, (2008), 323–330.
6.     Deng, Q.H., Zhou, J., Mei, C. and Shen, Y.M., "Fluid, heat and contaminant transport structures of laminar double-diffusive mixed convection in a two-dimensional ventilated enclosure", International Journal of Heat and Mass Transfer, Vol. 47, No. 24, (2004), 5257–5269.
7.     Clear, R.D., Gartland, L. and Winkelmann, F., "An empirical correlation for the outside convective air-film coefficient for horizontal roofs", Journal of Energy and Buildings, Vol. 35, No. 8, (2003), 797–811.
8.     Kaya, A., Aydin, O. and Dincer, I., "Numerical modeling of heat and mass transfer during forced convection drying of cylindrical moist objects", Journal of Numerical Heat Transfer, Vol. 51, No. 9, (2007), 843–854.
9.     Kaya, A., Aydin, O. and Dincer, I., "Heat and mass transfer modeling of recirculating flows during air drying of moist objects for various dryer configurations", Journal of Numerical Heat Transfer, Vol. 53, No. 1, (2008), 18-34.
10.   Xamán, J., Ortiz, A., Álvarez, G. and Chávez, Y., "Effect of a contaminant source (CO2) on the air quality in a ventilated room", Journal of Energy, Vol. 36,  (2011), 3302–3318.
11.   Pal, D. and Mondal, H., "Effects of Soret Dufour, chemical reaction and thermal radiation on MHD non-Darcy unsteady mixed convective heat and mass transfer over a stretching sheet", Communications in Nonlinear Science and Numerical Simulation, Vol. 16, No. 4, (2011), 1942–1958.
12.   Patankar, S.V., "Numerical heat transfer and fluid flow". Washington DC, Hemisphere Publication Corporation, (1980).
13.   Patankar, S.V., "Computation of Conduction and duct flow heat transfer innovative", USA: Resaerch Inc., (1991).