International Scientific Journal


The article represents an experimental investigation of friction and heat transfer characteristics of divergent / convergent rectangular ducts with an inclination angle of 1˚ in the y-axis. Measurements were taken for a convergent / divergent rectangular duct of aspect ratio AR at inlet1.25 and outlet in convergent channel 1.35; but in case of divergent duct it can be reversed. The four uniform rib heights, e = 3, 6, 9 and 12 mm the ratio between rib height to hydraulic mean diameter (e/Dm) are 34.8, 69.7, 104.6 and 138.7 a constant rib pitch distance, P = 60 mm has been used. The flow rate in terms of average Reynolds number based on the hydraulic mean diameter (Dm) is 86 mm of the channel was in a range of 20,000 to 50,000. The two ceramic heating strip of 10 mm thickness is used as a heating element have attached on top and bottom surfaces for the test sections. The heat transfer performance of the divergent / convergent ducts for 3, 6, 9 and 12 mm ribs was conducted under identical mass flow rate based on the Reynolds number. In our experiments has totally 8 different ducts were used. In addition, the acceleration / deceleration caused by the cross section area, the divergent duct generally shows enhanced heat transfer behavior for four different rib sizes, while the convergent duct has an appreciable reduction in heat transfer performance. From result point view divergent duct with 3 mm height ribbed square duct gets maximum heat transfer coefficient with minimum friction loss over the other convergent / divergent ducts.
PAPER REVISED: 2014-02-22
PAPER ACCEPTED: 2014-07-12
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2015, VOLUME 19, ISSUE Issue 6, PAGES [2219 - 2231]
  1. Abuaf, N., Kercher, D.M., The heat transfer and turbulence in a turbine blade cooling circuit. ASME Journal turbomachinery, vol.116, (1994), No.1, pp. 169-177
  2. Han, J.C., Park, J.S., Developing heat transfer in rectangular channel with rib turbulators, International Journal Heat Mass Transfer, vol.31,(1988), No.1, pp.183-195
  3. Han, J.C., Heat transfer and friction characteristics in rectangular channels with rib turbulators, Journal Heat Transfer, vol.110, (1988), pp.321-328
  4. Wagner, J.H., Johnson, B.V., Graziani, R.A., Yeh, F.C., Heat transfer in rotation serpectine passages with trips normal to the flow, Journal of Turbomachinery, vol.114, (1992), pp. 847-857
  5. Johnson, B.V., Wagner, J.H., Steduber, G.D., Yeh, F.C., Heat transfer in rotating serpentine passages with trips skewed to the flow, Journal of Turbomachinery. Vol.116, (1994), pp. 113-123
  6. Johnson, B.V., Wagner, J.H., Steuber, G.D., Effect of rotation on coolant passage heat transfer, NASA contractor Report No. 4396, NASA Contractor, USA, 1993
  7. Chen, Y., Nikitopoulos, D.E., Hibbs, R., Acharya, S., Myrum. T.A., Detailed mass transfer distribution in a ribbed coolant passage, International Journal Heat Mass Transfer, vol.43, (2000), pp. 1479-1492
  8. Bo.T., Lacovides, H., Launder, B.E., Developing buoyancy modified turbulent flow in ducts rotating in orthogonal mode, Journal of Turbomachinery, vol.117, (1995), pp. 474-484
  9. Lacovides, H., The Computation of flow and heat transfer through rotating ribbed passage, International Journal Heat Fluid flow, vol.19, (1988), pp. 393-400
  10. Sivakumar, K., Natarajan, E., Kulasekharan, N., Heat transfer and pressure drop comparison between smooth and different sized rib . roughened divergent rectangular ducts, International journal of Engineering and Technology, vol. 6,(2014), No.1, pp. 263-272
  11. Sivakumar, K., Natarajan, E., Kulasekharan, N., Influence of Rib Height on Heat Transfer Augmentation . Application to Aircraft Turbines, International Journal of Turbo Jet Engines, vol.31, (2014),No.1, pp. 87-95, DOI:10.1515/tjj2013-0035
  12. Qantani, M.A., Chen, H.C., Han, J.C., A numerical study of flow and heat transfer in rotating rectangular channels (AR = 4) with 45¢ª rib turbulators by Reynolds stress turbulence model. Journal Heat Transfer, vol.125, (2003), No.1, pp. 19-26
  13. Wang, L.H., Tao, W.Q., Wang, Q.W., Wong, T.T., Experimental study of developing turbulent flow and heat transfer in ribbed convergent/divergent square duct. International Journal of Heat and fluid flow, vol.22, (2001), pp. 603 . 613
  14. Rongguang J., Arash S., Bengt.S., Heat transfer enhancement in square ducts with V-shaped ribs of various angles, Proceedings of ASME Turbo Expo, Power for land, sea and air, Amsterdam, The Netherlands, Vol.3, (2002) pp.469-476
  15. Chandra,P.R., Alexander,C.R., Han, J.C., Heat transfer and friction behaviours in rectangular channels with varying number of ribbed walls, International journal of Heat and Mass Transfer, vol.46, (2003), pp. 481-495
  16. Amro, M., Wigand, B., Poser, R., Schnieder, M., An experimental investigation of the heat transfer in a ribbed triangular cooling channel, International journal of Thermal Science. Vol.46, (2007), pp. 491-500
  17. Abhishek, G., SriHarsha, V., Prabhu,S.V., Vedula, R.P., Local heat transfer distribution in a square channel with 90¢ª continuous, 90¢ª saw tooth profiled and 60¢ª broken ribs, Experimental Thermal and Fluid Science. Vol.32, (2008), pp. 997-1010
  18. Thianpong,C., Chomopookham,T., Skullong,S., Promvonage,P., Thermal characterization of turbulent flow in a channel with isosceles triangular ribs, International communication in heat and mass transfer, vol.36, (2009), pp.712-717
  19. Md.Julker,N., GyeongHwan,L., HanShik, C., Myoungkuk,JI., Hyomin,J., Turbulence and pressure drop behaviours around semicircular ribs in a rectangular channel, Thermal Science, online-first vol.00, (2014), pp. 419-430
  20. Caliskan,S., Baskaya, S., Experimental investigation of impinging jet array heat transfer from a surface with V-Shaped and convergent-divergent ribs, International Journal of Thermal Science, vol.59, (2012), pp.234-246
  21. Abdulrazzaq,T., Togun,H., AAriffin, MK., Kazi,S,N., Adam, NM., Masuri,S., Numerical simulation on heat transfer enhancement in channel by triangular ribs, vol.7, (2013), No.8, pp.49-53
  22. Sriharsha,V., Prabhu, S.V., Vedula, R,P., Influence of rib height on the local heat transfer distribution and pressure drop in a square channel with 90¢ª continuous and 60¢ª V-broken ribs, Applied Thermal Engineering,Vol.29, (2009),No.11-12, pp.2444-2456
  23. Momir, S., Darko, K., Rudolf, T., Development of a two zone turbulence model and its application to the cycle-Simulation, Thermal Science, vol.18, No.1, (2014), pp-1-16.
  24. Vukman,B., Martin, S., Branislav, S., Experimental investigation of turbulent structures of flow around a sphere, Thermal Science, vol.10, (2006), No.2, pp.97-112.
  25. Kline, S.J., McClintock,F.A., Describing uncertainties in single sample experiments. Mechanical Engineering, vol.75, (1953), pp. 3-8.
  26. Moffat. R.J., Describing the uncertainties in experimental results, Experimental Thermal Fluid Science, vol.1 (1988), pp-3-17
  27. Box. G. E. P., Hunter. W.G., Hunter. J.S., Statistics for Experimenters, Wiley, New York, (1978), pp- 453-509

© 2024 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence