THERMAL SCIENCE

International Scientific Journal

Thermal Science - Online First

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Heat transfer augmentation characteristics of a fin punched with curve trapezoidal vortex generators at the rear of tubes

ABSTRACT
The thermal-hydraulic characteristics of a novel fin punched with curve trapezoidal vortex generators (CTVGs) are investigated numerically. The effects of multi-parameters including the geometry of CTVG, the location of CTVGs, and working condition on thermal performance are considered. On one hand, CTVGs can availably lessen the size of tube wake zone, decrease the mechanical energy consumption and heighten the fin heat transfer ability in this area. On the other hand, the secondary flow strength is strengthened because the longitudinal vortices generated by CTVGs, which efficiently enhances the heat transfer on the fin downstream CTVGs. Close relationship exists between the volume-averaged secondary flow strength and the mean Nusselt number. For studied cases, the optimal circumferential location angle of β = 90º is found, while the optimal radial location Dg is about 1.8 times the tube outside diameter. The smaller is the height or base length of CTVGs, the better the thermal performance of the enhanced fin punched with CTVGs. Better thermal performance is achieved as the fin spacing is about 0.24 times the tube outside diameter.
KEYWORDS
PAPER SUBMITTED: 2021-08-27
PAPER REVISED: 2021-11-12
PAPER ACCEPTED: 2021-11-15
PUBLISHED ONLINE: 2022-01-02
DOI REFERENCE: https://doi.org/10.2298/TSCI210827352L
REFERENCES
  1. Fiebig, M., Vortex Generators for Compact Heat Exchangers, Journal of Enhanced Heat Transfer, 2 (1995), 1-2, pp. 43-61
  2. Jacobi, A. M., Heat Transfer Surface Enhancement Through the Use of Longitudinal Vortices: a Review of Recent Progress, Experimental Thermal and Fluid Science, 11 (1995), 3, pp. 295-309
  3. Ma T., et al., A Review on Thermoelectric-Hydraulic Performance and Heat Transfer Enhancement Technologies of Thermoelectric Power Generator System, Thermal Science, 22(2018), 5, pp. 1885-1903
  4. Lei, Y. G., et al., Hydrodynamics and Heat Transfer Characteristics of a Novel Heat Exchanger with Delta-Winglet Vortex Generators, Chemical Engineering Science, 65 (2009), 5, pp. 1551-1562
  5. Lemouedda, A., et al., Optimization of the Angle of Attack of Delta-Winglet Vortex Generators in a Plate-Fin-and-Tube Heat Exchanger, International Journal of Heat and Mass Transfer, 53 (2010), 23, pp. 5386-5399
  6. Chen, Y., et al., Conjugate Heat Transfer of a Finned Oval Tube with a Punched Longitudinal Vortex Generator in Form of a Delta Winglet-Parametric Investigation of the Winglet, Int. J. Heat Mass Transfer, 41 (1998), 23, pp. 3961-3978
  7. Kim, E. and Yang, J. S., An Experimental Study of Heat Transfer Characteristics of a Pair of Longitudinal Vortices Using Color Capturing Technique, International Journal of Heat and Mass Transfer, 45 (2002), 16, pp. 3349-3356
  8. Tiggelbeck, S., et al., Experimental Investigations of Heat Transfer Enhancement and Flow Losses in a Channel with Double Rows of Longitudinal Vortex Generators, International Journal of Heat and Mass Transfer, 36 (1993), 9, pp. 2327-2337
  9. Chen, Y., et al., Heat Transfer Enhancement of Finned Oval Tubes with Staggered Punched Longitudinal Vortex Generators, International Journal of Heat and Mass Transfer, 43 (2000), 3, pp. 417-435
  10. Wang, Y., Numerical Study of Hydrodynamics and Thermal Characteristics of Heat Exchangers with Delta Winglets, Thermal Science, 24 (2020), 1A, pp. 325-338
  11. Naik, H. and Tiwari, S., Thermal Performance Analysis of Fin-Tube Heat Exchanger with Staggered Tube Arrangement in Presence of Rectangular Winglet Pairs, International Journal of Thermal Sciences, 161 (2021), pp. 106723-20
  12. Sarangi, S. K., et al., Numerical Analysis of Thermofluid Performance of Fin-and-Tube Heat Transfer Surface Using Rectangular Winglets, Journal of Heat Transfer, 141 (2019), 10, pp. 101801-13
  13. Gorji, M., et al., Numerical Analysis on Longitudinal Location Optimization of Vortex Generator in Compact Heat Exchangers, International Journal for Numerical Methods in Fluids, 66 (2011), 6, pp. 705-713
  14. Leu, J. S., et al., Heat Transfer and Fluid Flow Analysis in Plate-Fin and Tube Heat Exchangers with a Pair of Block Shape Vortex Generators, International Journal of Heat and Mass Transfer, 47 (2004), 19, pp. 4327-4338
  15. Dupont, F., et al., Experimental Study of the Flow in a Compact Heat Exchanger Channel With Embossed-Type Vortex Generators, Journal of Fluids Engineering, 125 (2003), 4, pp. 701-709
  16. Lin, Z. M., et al., Numerical Study on Heat Transfer of Circular Tube Bank Fin Heat Exchanger with Interrupted Annular Groove Fin, Applied Thermal Engineering, 73 (2014), 2, pp. 1465-1476
  17. Gholami, A. A., et al., Heat Transfer Enhancement and Pressure Drop for Fin-and-Tube Compact Heat Exchangers with Wavy Rectangular Winglet-Type Vortex Generators, International Communications in Heat and Mass Transfer, 54 (2014), pp. 132-140
  18. Zhou, G. and Ye, Q., Experimental Investigations of Thermal and Flow Characteristics of Curved Trapezoidal Winglet Type Vortex Generators, Applied Thermal Engineering, 37 (2012), pp. 241-248
  19. Lin, Z. M., et al., Numerical Study of Flow and Heat Transfer Enhancement of Circular Tube Bank Fin Heat Exchanger with Curved Delta-Winglet Vortex Generators, Applied Thermal Engineering, 88 (2015), pp. 198-210
  20. Lin, Z. M., et al., Thermal and Flow Characteristics of a Channel Formed by Aligned Round Tube Bank Fins Stamped with Curve Delta-Winglet Vortex Generators, Thermal Science and Engineering Progress, 26 (2021), pp. 101113-13
  21. Gong, B., et al., Heat Transfer Characteristics of a Circular Tube Bank Fin Heat Exchanger with Fins Punched Curve Rectangular Vortex Generators in the Wake Regions of the Tubes, Applied Thermal Engineering, 75 (2015), pp. 224-238
  22. Wang, Q., et al., Investigation on Heat Transfer Performance and Flow Resistance Characteristics in Finned-Tube Heat Exchangers With Different Vortex Generator Positions, Journal of Heat Transfer, 141 (2019), 9, pp. 091804-10
  23. Oh, Y. and Kim, K., Effects of Position and Geometry of Curved Vortex Generators on Fin-Tube Heat-Exchanger Performance Characteristics, Applied Thermal Engineering, 189 (2021), pp. 116736-13
  24. Tala, J. V. S. , et al., Tube Pattern Effect on Thermal Hydraulic Characteristics in a Two-Rows Finned-Tube Heat Exchanger, International Journal of Thermal Sciences 60 (2012), pp. 225-235
  25. Lin, Z. M., et al., A New Method to Specify the Outlet Boundary Condition of Fluid Flow in the Channel Formed by Tube Bank Fins, Computational Thermal Sciences, 3 (2011), 6, pp. 445-459
  26. Wang, L. C., et al., The Characteristic Temperature in the Definition of Heat Transfer Coefficient on the Fin Side Surface in Tube Bank Fin Heat Exchanger, Numerical Heat Transfer, Part A: Applications, 60 (2011), 10, pp. 848-866
  27. Lin, Z. M., The Characteristics of Secondary Flow Heat Transfer Enhancement in Circular Tube with Twisted Tape or Vortex Generators. Ph.D. thesis. Lanzhou Jiaotong University, China, (2011)
  28. Eiseman, P. R., A Multi-Surface Method of Coordinate Generation, Journal of Computational Physics, 33 (1979), 1, pp. 118-150
  29. Eriksson, L. E., Practical Three-Dimension Mesh Generation Using Transfinite Interpolation, SIAM J. Sci. Stat. Comp, 6 (1985), pp. 712-741
  30. Li, Z. Y. and Tao, W. Q., A New Stability-Guaranteed Second-Order Difference Scheme, Numerical Heat Transfer, Part B: Fundamentals, 42 (2002), 4, pp. 349-365
  31. Tao, W. Q., Numerical Heat Transfer, Second ed., Xi'an Jiaotong University Press, Xi'an, China, (2001)
  32. Rhie, C. M. and Chow, W. L., Numerical Study of the Turbulent Flow Past an Airfoil with Trailing Edge Separation, AIAA J, 21 (1983), pp. 1525-1532
  33. Lin, Z. M. and Wang, L. B., A Multi-Domain Coupled Numerical Method for a Flat Tube Bank Fin Heat Exchanger with Delta-Winglet Vortex Generators, Numerical Heat Transfer, Part A: Applications, 65 (2014), 12, pp. 1204-1229
  34. Hu, W. L., et al., The Optimum Fin Spacing of Circular Tube Bank Fin Heat Exchanger with Vortex Generators, Heat and Mass Transfer, 49 (2013), 9, pp. 1271-1285