Vol. 1, No. 4 (November 1988) 211-218   

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M. Molki and A. R. Mostoufizadeh

Department of Mechanical Engineering
Esfehan University of Technology, Esfehan, Iran
( Received: July 1988 )

Abstract    An experimental investigation was conducted to study the average and the fully-developed heat (mass) transfer coefficients in a rectangular smooth duct and a duct with repeated-baffle blockages. The focus of attention in this work is the conventional correlation Nu / Nufd 1 + C / ( X / D ) for the average heat transfer coefficient. It was shown that for relatively short ducts, the coefficient C is not constant but, in general, it depends on the length of the duct. The experiments were carried out via a mass transfer technique and the analogy between heat and mass transfer was employed to predict the heat transfer coefficients. The flow Reynolds number ranged from 3000 to 50,000 with the height of the baffles equal to h/H = 0, 0.125, 0.25 and 0.50.



1. Chandra, P. R., Han, J. C. and Lau, S. C., “Effect of Rib Angle on Local Heat/Mass Transfer Distribution in a two-Pass Rib-Roughened Channel” , ASME Journal of Turbomachinery, Vol. 110, (1988), 233-241.
2. Karlekar, B. V. and Desmond, R. M., “Heat transfer 2nd ed.”, West Publishing Co., St. Paul, Minnesota, (1982).
3. Kays, W. M. and Crawford, M. E., “Convective Heat and Mass Transfer, 2nd ed.”, New York, (1980), 270.
4. Al-Arabi, M., “Turbulent heat Transfer in the Entrance Region of a tube”, Heat Transfer Engineering, Vol. 3, (1982), 76-83.
5. Molki, M. and Sparrow, E. M., “An Empirical Correlation for the Average Heat Transfer Coefficient in Circular Tubes”, ASME Journal of Heat Transfer, Vol. 108, (1986), 482-484.
6. Eckert, E. R. G., “Analogies to Heat Transfer Processes”, in Measurements in Heat Transfer, edited by E. R. G. Eckert and Goldstein, R. J., Hemisphere Publishing Corp., Washington, DC, (1976), 397-423.
7. Sparrow, E. M. and Wachtler, K. P., “Transfer Cofficients on the Surfaces of a Transverse Plate Situated in a Duct Flow”, International Journal of Heat and Mass Transfer, Vol. 21, (1978), 761-767.
8. Sogin, H. H., “Sublimation from Disks to Air Streams Flowing Normal to Their Surrfaces”, Trans.Am. Soc. Mech. Engrs., Vol. 89, (1958), 61-69.
9. Mostoufizadeh, A. R., “An Experimental Study of the Effect of Baffles Situated Normal to Airflow on Heat Transfer in Ducts”, M. sc. Thesis, Esfahan University of Technology, (1988).
10. Gnielinski, V., “New Equations for Heat and Mass Transfer in Turbulent Pipe and Channel Flow” International Chemical Engineering, Vol. 16, (1976), 359-386.
11. Berner, C., Durst, F. and McEligot, D. M., “Flow Around Baffles”, ASME Paper, Vol. 83, No. 9, (1983).
12. Kelkar, K. M. and Patankar, S. V., “Numerical Prediction of Flow and Heat Transfer in a Parallel Plate Channel with Staggered Fins” , ASME Journal of Heat Transfer, Vol. 109, (1987), 25-30.

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