THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

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Effect of wavy fin usage on thermal performance of heat exchanger used in combi boilers

ABSTRACT
In this study, performance of a heat exchanger used in combi boilers was investigated numerically for different fin geometries. Analyses were performed at the boiler operation conditions. A commercial computational fluid dynamics (CFD) software package (FLUENT) was used for numerical simulations. 3-D steady-state turbulent flow field analysis was carried out and k-ε model was preferred as the turbulence model. In the analysis, it was assumed that the heat transfer phenomenon occurred both by conduction and convection. Flat fin geometry was taken as a reference for the investigation. Variation of the heat transfer and pressure drop values for the wavy fin were compared with the reference geometry. The wave angle and wave radius were taken as the parameters for the wavy fins. For different fin geometries; the outlet temperature of the combustion gases, the heat transfer to the water and the pressure drop were calculated and the results were presented. Compared with flat fin, average decrease for the outlet temperature of hot gases was obtained as 4 K and average increase for the heat transfer to the water was calculated as 0,68 W. On the other hand, the average pressure drop in the heat exchanger with wavy fins was about 70% higher than the flat fin.
KEYWORDS
PAPER SUBMITTED: 2018-03-30
PAPER REVISED: 2018-06-13
PAPER ACCEPTED: 2018-06-14
PUBLISHED ONLINE: 2018-09-30
DOI REFERENCE: https://doi.org/10.2298/TSCI180330189Y
REFERENCES
  1. Benim, A.C., Cagan, M. and Gunes, D., Computational Analysis Of Transient Heat Transfer In Turbulent Pipe Flow, Int. J. Therm. Sci., 43 (2004), 8 SPEC. ISS., pp. 725-732
  2. Benim, A.C., Ozkan, K., Cagan, M. and Gunes, D., Computational Investigation Of Turbulent Jet Impinging Onto Rotating Disc, Int. J. Numer. Methods Heat&Fluid Flow, 17 (2007), 3, pp. 284-301
  3. Chattopadhyay, H., Benim, A.C., Turbulent Heat Transfer Over A Moving Surface Due To Impinging Slot Jets, J. Heat Transfer, 133 (2011), 10, Article number:104502, 5 pages
  4. Benim, A.C., Chattopadhyay, H. and Nahavandi, A., Computational Analysis Of Turbulent Forced Convection In A Channel With A Triangular Prism, Int. J. Therm. Sci., 50 (2011), 10, pp. 1973-1983
  5. Bhattacharyya, S., Chattopadhyay, H. and Benim, A.C., Simulation Of Heat Transfer Enhancement In Tube Flow With Twisted Tape Insert, Prog. Comput. Fluid Dyn., 17 (2017), 3, pp. 193-197
  6. Oclon, P., Lopata, S., Nowak, M. and Benim, A.C.,Numerical Study On The Effect Of Inner Tube Fouling On The Thermal Performance Of High-temperature Fin-and-tube Heat Exchanger, Progess Comput. Fluid Dyn., 15 (2015), 5, pp. 290-306
  7. Wang, C.C., Fu, W.L. and Chang, C.T., Heat Transfer And Friction Characteristics Of Typical Wavy Fin-and-tube Heat Exchangers, Exp. Therm. Fluid Sci., 14 (1997), 2, pp. 174-186
  8. Jang, J., Chen, L., Numerical Analysis Of Heat Transfer And Fluid Flow In A Three-dimensional Wavy-fin And Tube Heat Exchanger, Int. J. Heat Mass Transf., 40 (1997), 16, pp. 3981-3990
  9. Tao, Y.B., He, Y.L., Huang, J., Wu, Z.G. and Tao, W.Q., Numerical Study Of Local Heat Transfer Coefficient And Fin Efficiency Of Wavy Fin-and-tube Heat Exchangers, Int. J. Therm. Sci., 46 (2007), 8, pp. 768-778
  10. Junqi, D., Jiangping, C., Zhijiu, C., Yimin, Z. and Wenfeng, Z., Heat Transfer And Pressure Drop Correlations For The Wavy Fin And Flat Tube Heat Exchangers, Appl. Therm. Eng., 27 (2007), 11-12, pp. 2066-2073
  11. Pourahmad, S., Pesteei, S.M., Effectiveness-NTU Analyses In A Double Tube Heat Exchanger Equipped With Wavy Strip Considering Various Angles, Energy Convers. Manag., 123 (2016), pp. 462-469
  12. Sakr, M., Convective Heat Transfer And Pressure Drop In V-corrugated Channel With Different Phase Shifts, Heat Mass Transf., 51 (2015), 1, pp. 129-141
  13. Wang, J., Gao, X., and Li, W., Flow And Heat Transfer Characteristics In A Channel Having Furrowed Wall Based On Sinusoidal Wave, Korean J. Chem. Eng., 32 (2015), 11, pp. 2187-2203
  14. Rashidi, M.M., Hosseini, A., Pop, I., Kumar, S. and Freidoonimehr, N., Comparative Numerical Study Of Single And Two-phase Models Of Nanofluid Heat Transfer In Wavy Channel, Appl. Math. Mech. (English Ed., 35 (2014), 7, pp. 831-848
  15. Goyal, R., Bhargava, R., EFGM Simulation Of Pulsating Doublediffusive Effect On Transpiration Cooling In Nanofluid Filled Wavy Channel, Int. J. Appl. Comput. Math., 3 (2017), 3, pp. 1847-1860
  16. Singh, N., Sivan, R., Sotoa, M., Faizal, M. and Ahmed, M.R., Experimental Studies On Parallel Wavy Channel Heat Exchangers With Varying Channel Inclination Angles, Exp. Therm. Fluid Sci., 75 (2016), pp. 173-182
  17. Bahaidarah, H.M.S., Sahin, A.Z., Thermodynamic Analysis Of Fluid Flow In Channels With Wavy Sinusoidal Walls, Therm. Sci., 17 (2013), 3, pp. 813-822
  18. Gui, X., Song, X., Li, T. and Tang, D., Analysis On Three-Dimensional Flow And Heat Transfer In A Cross Wavy Primary Surface Recuperator For A Microturbine System, Therm. Sci., 19 (2015), 2, pp. 489-496
  19. Gülcan, Ö.E., Numerical Analysis of Heat Exchanger Used in Combi Boilers, Postgraduate thesis, Sakarya University, Sakarya, Turkey, 2015
  20. Ansys, I., ANSYS FLUENT Theory Guide, Knowl. Creat. Diffus. Util., 15317 (2009), November, pp. 724-746
  21. Cengel, Y.A., Heat And Mass Transfer: A Practical Approach, 2006