Heat transfer and fluid flow analysis of an artificially roughened solar air heater: a CFD based investigation

Abstract

In this paper, the effect of rib (circular sectioned) spacing on average Nusselt number and friction factor in an artificially roughened solar air heater (duct aspect ratio, AR= 5:1) is studied by adopting the computational fluid dynamics (CFD) approach. Numerical solutions are obtained using commercial software ANSYS FLUENT v12.1. The computations based on the finite volume method with the semi-implicit method for pressure-linked equations (SIMPLE) algorithm have been conducted. Circular sectioned transverse ribs are applied at the underside of the top of the duct, i.e., on the absorber plate. The rib-height-to-hydraulic diameter ratio (e/D) is 0.042. The rib-pitch-to-rib-height (P/e) ratios studied are 7.14, 10.71, 14.29 and 17.86. For each rib spacing simulations are executed at six different relevant Reynolds numbers from 3800 to 18000. The thermo-hydraulic performance parameter for P/e = 10.71 is found to be the best for the investigated range of parameters at a Reynolds number of 15000.

Key words： heat transfer; pressure drop; thermo-hydraulic performance parameter

References

1 DuffieJ A, BeckmanW A. Solar Engineering of Thermal Processes. 2nd edition. New York: Wiley, 1980

2 YadavA S, BhagoriaJ L. Renewable energy sources-an application guide. International Journal of Energy Science, 2013, 3(2): 70-90

3 HansV S, SainiR P, SainiJ S. Performance of artificially roughened solar air heaters-a review. Renewable & Sustainable Energy Reviews, 2009, 13(8): 1854-1869

4 BhushanB, SinghR. A review on methodology of artificial roughness used in duct of solar air heaters. Energy, 2010, 35(1): 202-212

5 KumarA, SainiR P, SainiJ S. Heat and fluid flow characteristics of roughened solar air heater ducts-a review. Renewable Energy, 2012, 47: 77-94

6 ChaubeA, SahooP K, SolankiS C. Analysis of heat transfer augmentation and flow characteristics due to rib roughness over absorber plate of a solar air heater. Renewable Energy, 2006, 31(3): 317-331

7 KumarS, SainiR P. CFD based performance analysis of a solar air heater duct provided with artificial roughness. Renewable Energy, 2009, 34(5): 1285-1291

8 KarmareS V, TikekarA N. Analysis of fluid flow and heat transfer in a rib grit roughened surface solar air heater using CFD. Solar Energy, 2010, 84(3): 409-417

9 SharmaA K, ThakurN S. CFD based fluid flow and heat transfer analysis of a v- shaped roughened surface solar air heater. International Journal of Engineering Science and Technology, 2012, 4(5): 2115-2121

10 GandhiB K, SinghK M. Experimental and numerical investigations on flow through wedge shape rib roughened duct.Journal of the Institution of Engineers (India). Part MC, 2010, 90(1): 13-18

11 YadavA S, BhagoriaJ L. A CFD analysis of a solar air heater having triangular rib roughness on the absorber plate. International Journal of ChemTech Research, 2013, 5(2): 964-971

12 YadavA S, BhagoriaJ L. A CFD based heat transfer and fluid flow analysis of a conventional solar air heater. Journal of Engineering Science and Management Education, 2013, 6(2): 138-147

13 YadavA S, BhagoriaJ L. Numerical investigation of flow through an artificially roughened solar air heater. International Journal of Ambient Energy, 2013, (in press)

14 YadavA S, BhagoriaJ L. A numerical investigation of turbulent flows through an artificially roughened solar air heater. Numerical Heat Transfer A, 2013, (in press)

15 YadavA S, BhagoriaJ L. Modeling and simulation of turbulent flows through a solar air heater having square-sectioned transverse rib roughness on the absorber plate. Scientific World Journal, 2013, 2013: 827131

PMID

16 YadavA S, BhagoriaJ L. Heat transfer and fluid flow analysis of solar air heater: a review of CFD approach. Renewable & Sustainable Energy Reviews, 2013, 23: 60-79

17 American Society of Heating. Refrigeration and Air Conditioning Engineers. ASHRAE Standard 93 GA30329 Method of testing to determine the thermal performance of solar collectors. Atlanta: ASHRAE, 2003

18 SinghS, ChanderS, SainiJ S. Heat transfer and friction factor correlations of solar air heater ducts artificially roughened with discrete V-down ribs. Energy, 2011, 36(8): 5053-5064

19 SainiS K, SainiR P. Development of correlations for Nusselt number and friction factor for solar air heater with roughened duct having arc-shaped wire as artificial roughness. Solar Energy, 2008, 82(12): 1118-1130

20 KarmareS V, TikekarA N. Heat transfer and friction factor correlation for artificially roughened duct with metal grit ribs. International Journal of Heat and Mass Transfer, 2007, 50(21-22): 4342-4351

21 BopcheS B, TandaleM S. Experimental investigations on heat transfer and frictional characteristics of a turbulator roughened solar air heater duct. International Journal of Heat and Mass Transfer, 2009, 52(11-12): 2834-2848

22 TandaG. Performance of solar air heater ducts with different types of ribs on the absorber plate. Energy, 2011, 36(11): 6651-6660

23 GuptaD, SolankiS C, SainiJ S. Thermo-hydraulic performance of solar air heaters with roughened absorber plates. Solar Energy, 1997, 61(1): 33-42

24 PrasadB N, SainiJ S. Optimal thermohydraulic performance of artificially roughened solar air heaters. Solar Energy, 1991, 47(2): 91-96

25 LaunderB E, SpaldingD B. Lectures in Mathematical Models of Turbulence. London, England: Academic Press, 1972

26 PatankarS V. Numerical Heat Transfer and Fluid Flow. 1st edition. USA: Hemisphere Publishing Corporation, 1980

27 WebbR L, EckertE R G. Application of rough surface to heat exchanger design. International Journal of Heat and Mass Transfer, 1972, 15(9): 1647-1658

28 McAdamsW H. Heat Transmission. New York: McGraw-Hill Book Company, 1942

29 FoxW, PritchardP, McDonaldA. Introduction to Fluid Mechanics. New York: John Wiley & Sons, 2010, 754

30 VermaS K, PrasadB N. Investigation for the optimal thermohydraulic performance of artificially roughened solar air heaters. Renewable Energy, 2000, 20(1): 19-36

31 PrasadB N, SainiJ S. Effect of artificial roughness on heat transfer and friction factor in a solar air heater. Solar Energy, 1988, 41(6): 555-560