CFD Analysis of Heat Transfer Characteristics of Helical Coil Heat Exchangers

Abstract:

The applications of heat exchangers are vast and the enhancement of heat transfer and compact size are the key factors for designing the heat exchangers in order to achieve energy savings. In the field of tubular heat exchangers one of the possible ways for reducing the space occupied by the exchanger is by bending tube axis in helical shape. This option is particularly suitable when construction simplicity is needed and the geometry of the place in which the exchanger has to be housed is the cylindrical one. In this paper, an attempt is made to enhance the heat transfer rate without application of any external power. This is achieved by providing the helical tube in tubes. The parameters influencing the nature of flow in a helical coil heat exchanger are the tube geometry namely pitch coil diameter, pitch and tube diameter. CFD analysis is carried out to study these geometry effects on heat transfer and hydraulic characteristics by varying Reynolds number (hot fluid). The CFD results of velocity and temperature distribution in the heat exchanger are used to estimate the Nusselt number and heat transfer coefficient. This helps to arrive at an optimum value of Reynolds number and Nusselt number for the corresponding tube-to-coil diameter ratios.

• Periodical: Applied Mechanics and Materials (Volume 787)
• Pages: 172-176
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.787.172
• Online since: August 2015
• Authors: R. Maradona*, S. Rajkumar
• Keywords: CFD Analysis, Heat Exchangers, Helical Coils, Nusselt Number

References

[1] J. S. Jayakumar, S. M. Mahajani, J. C. Mandal, P. K. Vijayan, and Rohidas Bhoi, Experimental and CFD estimation of heat transfer in helically coiled heat exchangers, Chemical Engg Research and Design. 86 (2008) 221-232.

DOI: 10.1016/j.cherd.2007.10.021

[2] Dean W. R, Stream line motion of fluid in a curved pipe, Philosophical Magazine. 5 (1928) 673-695.

[3] T. J. Rennie, V. G .S. Raghavan, Experimental studies of a double-pipe helical heat exchanger, Experimental Thermal and Fluid Science. 29 (2005) 919–924.

DOI: 10.1016/j.expthermflusci.2005.02.001

[4] Xin R. C, Ebadian M. A, The effects of Prandtl numbers on local and average convective heat transfer characteristics in helical pipes, Journal of Heat Transfer. 119 (1997) 463–473.

DOI: 10.1115/1.2824120

[5] Shiva Kumar, K. Vasudevan Karanth, Numerical Analysis of a Helical Coiled Heat Exchanger using CFD. International Journal of Thermal Technologies. 3 (2013) 126-130.