Performance Improvement in Internally Finned Tube by Shape Optimization

Predictions of flow and heat transfer characteristics and shape optimization in internally finned circular tubes have been performed on three-dimensional periodically fully developed turbulent flow and thermal fields. For a trapezoidal fin profile, the effects of fin height h, upper fin widths d1, lower fin widths d2, and helix angle of fin ? on transport phenomena are investigated for the condition of fin number of N = 30. The CFD and mathematical optimization technique are coupled in order to optimize the shape of internally finned tube. The optimal solutions of the design variables (i.e., upper and lower fin widths, fin height and helix angle) are numerically obtained by minimizing the pressure loss and maximizing the heat transfer rate, simultaneously, for the limiting conditions of d1 = 0.5~1.5 mm, d2 = 0.5~1.5 mm, h= 0.5~1.5mm, ? = 10~30 degrees. The fully developed flow and thermal fields are predicted using the finite volume method and the optimization is carried out by means of the multi-objective genetic algorithm that is widely used in the constrained nonlinear optimization problem.

Authors:

• Kyoungwoo Park
• Byeong Sam Kim
• Hyo-Jae Lim
• Ji Won Han
• Park Kyoun Oh
• Juhee Lee
• Keun-Yeol Yu

Keywords:

• Computational fluid dynamics
• Genetic algorithm
• Internally finned tube with helix angle
• Optimization.

References:

[1] H.Y. Pak, K. Park, and M.S. Choi, "Numerical Analysis of the Flow and
Heat Transfer Characteristics for Forced Convection-Radiation in
Entrance Region of an Internally Finned Tubes," KSME Int. J., Vol. 12
no. 2, 1998, pp. 310~319.
[2] X.Liu, and M.K. Jensen, "Geometry Effects on Turbulent Flow and Heat
Transfer in Internally Finned Tubes," ASME J. of Heat Transfer,
Vol.123, 2001, pp. 1035~1044.
[3] G. Fabbri, "Heat Transfer Optimization in Internally Finned Tubes Under
Laminar Flow Conditions, Int. J. of Heat and Mass Transfer, Vol.41,
No.10, 1998, pp.1243-1253.
[4] J. Lee, J, S. Lee, and K. Park, , Flow/Heat Transfer Analysis and Shape
Optimization of a Heat Exchanger with Internally Finned Tube, Trans, of
the KSME (B), Vol.29, No.4, 2005, pp.1620-1629.
[5] Sanghwan Lee ,Juhee Lee, Kyoungwoo Park, An Application of
Multi-Objective Global Optimization Technique For Internally Finned
Tube, Korean Journal of Air- Conditioning and Refrigeration
Engineering, Vol 17, No. 10, 2005, pp. 938-946.
[6] A.C.Poloni, A. Giurgevich, L Onesti, and V.Pediroda, Hybridisation of a
Multi-Objective Genetic Algorithm, a Neural Network and a Classical
Optimizer for a Complex Design Problem in Fluid Dynamics,
Dipartimento diEnergetica Universita di Trieste, Italy, 1999.
[7] D.Goldberg, Genetic Algorithms in Search, Optimization and Machine
Learning, Addition-Wesley, 1989.
[8] Z. Michalewicz, Genetic Algorithms + Data Structures = Evolution
Programs, Springer-Verlog, , 1992.
[9] L.B. Booker, Improving Search in Genetic Algorithms", in Davis
L(Editor), "Genetic Algorithms and Simulated Annealing, Morgan
Kaufmann Publishers, Los Altos, CA, 1987.
[10] J.D. Schaffer, "Multiple objective optimization with vector evaluated
genetic algorithms", Proc. First Int. Conf. on Genetic Algorithms, pp.
93-100, 1985,.
[11] S. V.Patankar, C. H. Liu, and E. M. Sparrow, "Fully Developed Flow and
Heat Transfer in Ducts Having Streamwise-Periodic Variations of
Cross-Sectional Area", ASME J. of Heat Transfer, Vol. 99, 1977, pp.
180~186.
[12] W. Rodi, Turbulence models and their applications in hydraulics - a
state-art-of review, Book Publication of International Association for
Hydraulic Research, Delft, Netherlands, 1984.
[13] L. H.Norris and W. C. Reynolds, Turbulent Channel Flow with a Moving
Wavy Boundary, Report. FM-10, Department of Mechanical Engineering,
Stanford University, CA, 1975.
[14] STAR-CD Manual, 2001, Computational Dynamics, Co., London. U. K.
[15] J. P. Holman, Heat Transfer, McGraw-Hill Book Company, pp. 274~278,
1986.