NUMERICAL AND EXPERIMENTAL INVESTIGATION ON THE EFFECT OF RESTRICTION SHAPE ON CHARACTERISTICS OF AIRFLOW IN A SQUARE DUCT
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Abstract
Experimental and numerical investigation has been under taken to study turbulent flow of air through duct using restriction in different shapes and positions for Reynolds numbers ranges of (8.2x104 → 5.6x104).The numerical approach used in this work is the finite volume method for solution of elliptic partial differential equation for the modeling of turbulent (k-) model as well as wall function concept near the wall which was used to take the turbulent effects into consideration have been employed.The experimental test rigs were constructed from Perspex, and a fivehole pressure probe was used to measure the three component of air flow velocity vector in space.The results show that the total pressure drop depends on the shape and position of the restriction, and the pressure drop coefficient due to the restriction shape and position (kR) depends on two parameters; blockage area ratio (Ab) and the ratio between wetted perimeter to the free remainder perimeter (pe/Pe) and dose not depend on the Reynolds number ( for the same blockage area ratio Ab if the pe/Pe increases 40%, the coefficient kR increases 7% , and for the same pe/Pe, if the blockage area ratio increases 50% ,the coefficient kR increases 10%). But the pressure drop coefficient due to the friction (Cf) is a function of Reynolds.
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British-standard 1042, "Method for measurement of fluid flow in pipes", Part 2A, August,
Davidson, L., and Farhanieh, B., "A finite volume code employing collocated variable
arrangement and Cartesian velocity components for computational geometries.", Dep. Of
Thermo and Fluid Dynamics, Chalmers University of Technology, Sweden, November, 1995,
Publ. No. 95/11.
Han, J.C., Glicjsman, L.R., and Rohsenow, W.M.,(1978),"An investigation of heat transfer
and friction for rib-roughened surfaces. ", Int. J., Heat and Mass Transfer Vol. 21, pp. 1143-
Hanaa Abdul hadi" Numerical and Experimental Investigation on the Effect of Restriction
Shape on Characteristics of Airflow in a Square Duct." Ph.D thesis of Mechanical Engineering
of University of Technology,2006.
Han,J.C.,(1984),"Heat transfer and friction in channels with two opposite rib-roughened walls.
", Transaction of the ASME, Vol. 106, Nov. 1984.
Launder, B.T., and Spalding, D.B., "Lecturers in mathematical models of turbulence.'
Department of Mechanical Engineering, imperial college of Science and Technology, London,
England.
Lee, Y.N., (1986), "Heat transfer and pressure drop characteristics of an array of plates
aligned at angles to the flow in a rectangular duct. ", Int. J., Heat and Mass Transfer Vol. 29,
No. 10, pp. 1553-1563, 1986.
Massey B.S., "Mechanics of Fluids", 4th edition, Van Nostr and Reinhold, 1980.
Ooi , A. , Iaccarino , G., Durbin , P.A. , and Behnia , M. , (2002). " Reynolds averaged
simulation of flow and heat transfer in ribbed ducts. ", International Journal of Heat and Fluid
Flow, Vol. 23 , (2002) , pp. 750-757.
Ooi, A., Iaccarino, G., Durbin, P.A., and Behnia, M., (2003). "Simulation of turbulent flow
and heat transfer in complex passage. ", Journal of Heat and Fluid Flow , Vol. 23 , pp. 750-
Onbasioglu, S.U., and Huseyin Oube, H., (2003),"On enhancement of heat transfer with ribs.",
Applied Thermal Engineering, Vol. 24, Issue 1, January 2004, pp. 43-57.
Patanker, S.V., (1980), "Numerical heat transfer and fluid flow ", McGraw.Hill, New York.
Roberson and Crowe, "Engineering Fluid Mechanics." 6th edition, Copyright 1977, by John
Wilely and Sons, Inc.
Taslim, M.E., Li, T., and Spring, S.D., (1998)," Measurement heat transfer coefficients and
friction factor in passage rib-roughened on all walls", Transactions of ASME, Vol. 120, July,