Irreversibility Analysis and Numerical Simulation in a Finned-Tube Heat Exchanger Equipped with Block Shape Vortex Generator

Authors

Department of mechanical Engineering, Ferdowsi University of Mashhad, Iran

Abstract

In this paper the effect of block shape Vortex Generators (VGs) on an air-water fin-tube heat exchanger has been studied experimentally using exergy analysis method. Also the effect of these VGs on increasing heat transfer rate has been simulated numerically and the Results show a good agreement with the experiments. In this research we used a wind tunnel to produce wind flow over heat exchanger in the range of 0.054 kg/s to 0.069 kg/s. Hot water was circulating with the steady volume flow rate of 240 L/h and the temperature of 44 to 68 centigrade in the system. These experiments have been repeated with and without VGs on the heat exchanger. Results show using the VGs has reduced Air Side Irreversibility to Heat transfer Ratio (ASIHR). To reveal the effect of VGs on heat exchanger performance with respect to reducing ASIHR, a quantity is used namely Performance of Vortex Generator (PVG). The results represent that PVG values are in the range of less than 15% to over 35% which represents the good effects of VGs on the heat exchanger performance.

Keywords


      [1]      Kakac, S., Liu H., “Heat exchangers: selection, rating, and thermal design”, 2nd ed., CRC Press, 2002.

      [2]      Biswas, G., Mitra N. K., and Fiebig M., “Heat transfer enhancement in fin-tube heat exchangers by winglet type vortex generators”, International Journal of Heat and Mass Transfer, Vol. 37, 1994, pp. 283-291.

      [3]      Chen Y., Fiebig M., and Mitra N. K., “Heat transfer enhancement of a finned oval tube with punched longitudinal vortex generators in-line”, International Journal of Heat and Mass Transfer, Vol. 41, 1998, pp. 4151-4166.

      [4]      Chen Y., Fiebig M., and Mitra N. K., “Heat transfer enhancement of a finned oval tube with staggered punched longitudinal vortex generators”, International Journal of Heat and Mass Transfer, Vol. 43, 2000, pp. 417-435.

      [5]      Kotcioglu I., Caliskan S., Cansiz A., and Baskaya S., “Second law analysis and  heat  transfer in a cross flow heat exchanger with a new winglet-type vortex generator”, Energy, Vol. 35, 2010, pp. 3686-3695.

      [6]      Wang C. C., Lo J., Lin Y. T., and Liu M. S., “Flow visualization of wave-type vortex generators having inline fin-tube arrangement”, International Journal of Heat and Mass Transfer, Vol. 45, 2002, pp. 1933-1944.

      [7]      Tian L., He Y., Tao Y., and Tao W., “A comparative study on the air-side performance of wavy fin-and-tube heat exchanger with punched delta winglets in staggered and in-line arrangements”, International Journal of Thermal Science, Vol. 48, 2009, pp. 1765-1776.

      [8]      Fiebig M., Valencia A., and Mitra N. K., “Wing-type vortex generators for fin-and-tube heat exchangers”, Exp. Therm. Fluid Sci, Vol. 7, 1993, pp. 287-295.

      [9]      Valencia A., Fiebig M., and Mitra N. K., “Heat transfer enhancement by longitudinal vortices in a fin-and-tube heat exchangers element with flat tubes”, ASME J. Heat Transfer, Vol. 118, 1996, pp. 209-211.

     [10]     Joardar A., Jacobi A. M., “Heat transfer enhancement by winglet-type vortex generator arrays in compact plain-fin-and-tube heat exchangers”, International Journal of Refrigeration, Vol. 31, 2008, pp. 87-97.

     [11]     Wu S. Y., Yuan X. F., Li Y. R., and Xiao L., “Exergy transfer effectiveness on heat exchanger for finite pressure drop”, Energy, Vol. 32, 2007, pp. 2110-2120.

     [12]     ANSYS Inc. Fluent 6.3 users guide, Canonsburg, Pennsylvania 15317, USA: ANSYS Inc, Southpointe, 275 Technology Drive; 2006.