Experimental Investigation on Turbulent Convection in Solar Air Heater Channel Fitted with Delta Winglet Vortex Generator

doi:10.1016/S1004-9541(14)60030-6

Abstract

Abstract: The paper presents an experimental study on the heat transfer and flow friction characteristics in a solar air heater channel fitted with delta-winglet type vortex generators (DWs). The experiments are conducted by varying the airflow rate for Reynolds number in the range of 5000 to 24000 in the test section with a uniform heat-flux applied on the upper channel wall. Firstly, the DW pairs are mounted only at the entrance of the lower wall of the test channel (called DW-E) to create multiple vortex flows at the entry. The effect of two transverse pitches (R_P=P_t/H=1 and 2) at three attack angles (α=30°, 45° and 60°) of the DW-E with its relative height, b/H=0.5 (half height of channel) is examined. Secondly, the 30° DWs with three different relative heights (b/H 0.3, 0.4 and 0.5) are placed on the upper wall only (absorber plate, called DW-A) of the test channel. The experimental result reveals that in the first case, the 60° DW-E at R_P=1 provides the highest heat transfer and friction factor while the 30° DW-E at R_P=1 performs overall better than the others. In the second case, the 30° DW-A at b/H=0.5 yields the highest heat transfer and friction factor but the best thermal performance is found at b/H=0.4.

Key words: heat transfer intensification, delta-winglet, Reynolds number, friction factor, solar air heater, flat channel

摘要： The paper presents an experimental study on the heat transfer and flow friction characteristics in a solar air heater channel fitted with delta-winglet type vortex generators (DWs). The experiments are conducted by varying the airflow rate for Reynolds number in the range of 5000 to 24000 in the test section with a uniform heat-flux applied on the upper channel wall. Firstly, the DW pairs are mounted only at the entrance of the lower wall of the test channel (called DW-E) to create multiple vortex flows at the entry. The effect of two transverse pitches (R_P=P_t/H=1 and 2) at three attack angles (α=30°, 45° and 60°) of the DW-E with its relative height, b/H=0.5 (half height of channel) is examined. Secondly, the 30° DWs with three different relative heights (b/H 0.3, 0.4 and 0.5) are placed on the upper wall only (absorber plate, called DW-A) of the test channel. The experimental result reveals that in the first case, the 60° DW-E at R_P=1 provides the highest heat transfer and friction factor while the 30° DW-E at R_P=1 performs overall better than the others. In the second case, the 30° DW-A at b/H=0.5 yields the highest heat transfer and friction factor but the best thermal performance is found at b/H=0.4.

关键词: heat transfer intensification, delta-winglet, Reynolds number, friction factor, solar air heater, flat channel

Sompol Skullong, Pongjet Promvonge. Experimental Investigation on Turbulent Convection in Solar Air Heater Channel Fitted with Delta Winglet Vortex Generator[J]. Chin.J.Chem.Eng., 2014, 22(1): 1-10.

Sompol Skullong, Pongjet Promvonge. Experimental Investigation on Turbulent Convection in Solar Air Heater Channel Fitted with Delta Winglet Vortex Generator[J]. Chinese Journal of Chemical Engineering, 2014, 22(1): 1-10.

References

1 Promvonge, P., "Thermal augmentation in circular tube with twisted tape and wire coil turbulators", Energy Convers. Manag., 49, 2949-2955 (2008).
2 Promvonge, P., "Thermal performance in circular tube fitted with coiled square wires", Energy Convers. Manag., 49 (5), 980-987 (2008).
3 Thianpong, C., Chompookham, T., Skullong, S., Promvonge, P., "Thermal characterization of turbulent flow in a channel with isosceles triangular ribs", Int. Commun. Heat Mass Transfer, 36, 712-717 (2009).
4 Sripattanapipat, S., Promvonge, P., "Numerical analysis of laminar heat transfer in a channel with diamond-shaped baffles", Int. Commun. Heat Mass Transfer, 36 (1), 32-38 (2009).
5 Promvonge, P., Chompookham, T., Kwankaomeng, S., Thianpong, C., "Enhanced heat transfer in a triangular ribbed channel with longitudinal vortex generators", Energy Convers. Manag., 51 (6), 1242-1249 (2010).
6 Chompookham, T., Thianpong, C., Kwankaomeng, S., Promvonge, P., "Heat transfer augmentation in a wedge-ribbed channel using winglet vortex generators", Int. Commun. Heat Mass Transfer, 37, 163-169 (2010).
7 Promvonge, P., Khanoknaiyakarn, C., Kwankaomeng, S., Thianpong, C., "Thermal behavior in solar air heater channel fitted with combined rib and delta-winglet", Int. Commun. Heat Mass Transfer, 38, 749-756 (2011).
8 Sahu, M.M., Bhagoria, J.L., "Augmentation of heat transfer coefficient by using 90° broken transverse ribs on absorber plate of solar air heater", Renew. Energy, 30 (13), 2057-2063 (2005).
9 Mittal, M.K., Varun, Saini, R.P., Singal, S.K., "Effective efficiency of solar air heaters having different types of roughness elements on absorber plate", Energy, 32, 739-745 (2007).
10 Aharwal, K.R., Gandhi, B.K., Saini, J.S., "Experimental investigation on heattransfer enhancement due to a gap in an inclined continuous rib arrangement in a rectangular duct of solar air heater", Renew. Energy, 33, 585-596 (2008).
11 Varun, Saini, R.P., Singal, S.K., "Investigation of thermal performance of solar air heater having roughness elements as a combination of inclined and transverse ribs on the absorber plate", Renew. Energy, 33 (6), 1398-1405 (2008).
12 Momin, A.M.E., Saini, J.S., Solanki, S.C., "Heat transfer and friction in solar air heater duct with V-shaped rib roughness on absorber plate", Int. J. Heat Mass Transfer, 45, 3383-3396 (2002).
13 Chandra, P.R., Alexander, C.R., Han, J.C., "Heat transfer and friction behaviour in rectangular channels with varying number of ribbed walls", Int. J. Heat Mass Transfer, 46, 481-495 (2003).
14 Tanda, G., "Heat transfer in rectangular channels with transverse and V-shaped broken ribs", Int. J. Heat Mass Transfer, 47, 229-243 (2004).
15 Chang, S.W., Liou, T.M., Lu, M.H., "Heat transfer of rectangular narrow channel with two opposite scale roughened walls", Int. J. Heat Mass Transfer, 48, 3921-3931 (2005).
16 Katoh, K., Choi, K., Azuma, T., "Heat transfer enhancement and pressure loss by surface roughness in turbulent channel flows", Int. J. Heat Mass Transfer, 43, 4009-4017 (2000).
17 Varun, Saini, R.P., Singal, S.K., "A review on roughness geometry used in solar air heaters", Solar Energy, 81, 1340-1350 (2007).
18 Murugesan, P., Mayilsamy, K., Suresh, S., "Turbulent heat transfer and pressure drop in tube fitted with square-cut twisted tape", Chin. J. Chem. Eng., 18, 609-617 (2010).
19 Murugesan, P., Mayilsamy, K., Suresh, S., "Heat transfer and friction factor studies in a circular tube fitted with twisted tape consisting of wire-nails", Chin. J. Chem. Eng., 18, 1038-1042 (2010).
20 Gunes, S., Ozceyhan, V., Buyukalaca, O., "Heat transfer enhancement in a tube with equilateral triangle cross sectioned coiled wire inserts", Exp. Therm. Fluid Sci., 34 (6), 684-691 (2010).
21 Promvonge, P., Skullong, S., Kwankaomeng, S., Thiangpong, C., "Heat transfer in square duct fitted diagonally with angle-finned tape-Part 1: Experimental study", Int. Commun. Heat Mass Transfer, 39 (5), 617-624 (2012).
22 Promvonge, P., Skullong, S., Kwankaomeng, S., Thiangpong, C., "Heat transfer in square duct fitted diagonally with angle-finned tape-Part 2: Numerical study", Int. Commun. Heat Mass Transfer, 39 (5), 625-633 (2012).
23 Eiamsa-ard, S., Koolnapadol, N., Promvonge, P., "Heat transfer behavior in a square duct with tandem wire coil element insert", Chin. J. Chem. Eng., 20 (5), 863-869 (2012).
24 Gentry, M.C., Jacobi, A.M. "Heat transfer enhancement by delta-wing vortex generators on a flat plate: Vortex interactions with the boundary layer", Exp. Therm. Fluid Sci., 14 (3), 231-242 (1997).
25 Kwak, K.M., Torii, K., Nishino, K., "Simultaneous heat transfer enhancement and pressure loss reduction for finned-tube bundles with the first or two transverse rows of built-in winglets", Exp. Therm. Fluid Sci., 29 (5), 625-632 (2005).
26 Jacobi, A.M., Shah, R.K., "Heat transfer surface enhancement through the use of longitudinal vortices: A review of recent progress", Exp. Therm. Fluid Sci., 11 (3), 295-309 (1995).
27 Fiebig, M., "Embedded vortices in internal flow: Heat transfer and pressure loss enhancement", Int. J. Heat Fluid Flow, 16 (5), 376-388 (1995).
28 Tian, L.T., He, Y.L., Lei, Y.G., Tao, W.Q., "Numerical study of fluid flow and heat transfer in a flat-plate channel with longitudinal vortex generators by applying field synergy principle analysis", Int. Commun. Heat Mass Transfer, 36 (2), 111-120 (2009).
29 ANSI/ASME, "Measurement uncertainty", PTC 19. 1-1985, Part I, USA (1986).
30 Incropera, F., Dewitt, P.D., Fundamentals of Heat and Mass Transfer, 6th edition, John Wiley & Sons, USA (2007).

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