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Entropy Generation Analysis of Free Convection Film Condensation on a Vertical Ellipsoid with Variable Wall Temperature

Authors: Sheng-An Yang, Ren-Yi Hung, Ying-Yi Ho

Abstract:

This paper aims to perform the second law analysis of thermodynamics on the laminar film condensation of pure saturated vapor flowing in the direction of gravity on an ellipsoid with variable wall temperature. The analysis provides us understanding how the geometric parameter- ellipticity and non-isothermal wall temperature variation amplitude “A." affect entropy generation during film-wise condensation heat transfer process. To understand of which irreversibility involved in this condensation process, we derived an expression for the entropy generation number in terms of ellipticity and A. The result indicates that entropy generation increases with ellipticity. Furthermore, the irreversibility due to finite temperature difference heat transfer dominates over that due to condensate film flow friction and the local entropy generation rate decreases with increasing A in the upper half of ellipsoid. Meanwhile, the local entropy generation rate enhances with A around the rear lower half of ellipsoid.

Keywords: Ellipsoid, Free convection; Non-isothermal; Thermodynamic second law; Entropy

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1330469

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[1] S. A. Yang and C. H. Hsu, "Free and forced convection film condensation from a horizontal elliptical tube with a vertical plate and horizontal tube as special cases," Int. J. Heat and Fluid Flow, vol. 18, pp. 567-574, 1997.
[2] S. A. Yang and C. K. Chen, "Role of surface tension and ellipticity in laminar film condensation on horizontal elliptical tube," Int. J. Heat Mass Transfer, vol. 36, no.12, pp. 3135-3141, 1993.
[3] A. F. M. Ali and T. W. McDonald, "Laminar film condensation on horizontal elliptical cylinders: A first approximation for condensation on inclined tubes," ASHRAE Trans., vol. 83, pp. 242-249., 1977.
[4] A. Karimi, "Laminar film condensation on helical reflux condensers and related configurations," Int. J. Heat and Mass Transfer, vol. 20, pp. 1137-1144, 1977.
[5] S. B. Memory and J. W. Rose, "Free convection laminar film condensation on a horizontal tube with variable wall temperature," Int. J. Heat Mass Transfer, vol. 34, pp. 2775-2778, 1991.
[6] O. B. Adeyinka and G. F. Naterer, "Optimization correlation for entropy production and energy availability in film condensation," Int. Comm. Heat Mass Transfer, vol. 31, no. 4, pp. 513-524, 2004.
[7] W. W. Lin, D. J. Lee and X. F. Peng, "Second-law analysis of vapor condensation of FC-22 in film flows within horizontal tubes," J. Cihn. Inst. Chem. Engrs., vol. 32, pp. 89-94, 2001.
[8] S. C. Dung and S. A. Yang, "Second law based optimization of free convection film-wise condensation on a horizontal tube," Int. Comm. Heat Mass Transfer, Vol. 33, pp.636-644, 2006.
[9] G. C. Li and S. A. Yang, "Thermodynamic analysis of free convection film condensation on an elliptical cylinder," Accepted in J. of The Chinese Institute Engineers. vol.29, No5, pp.903-908, 2006.
[10] E. M. Rohsenow, "Heat transfer and temperature distribution in laminar film condensation," Trans. ASME, vol. 78, pp.1648-1654, 1956.
[11] S. A Yang and C. K Yang, "Effects of Surface Tension and Non-Isothermal Wall Temperature Variation upon Filmwise Condensation on Vertical Ellipsoids/Sphere," Proc. Royal Soc., London. A , vol.442, pp.301-312, 1993.
[12] W. C. Lee, S. Rahbar and J. W. Rose, "Film condensation of refrigerant 113 and ethanediol on a horizontal tube-effect of vapor velocity," ASME J. Heat Transfer, vol. 106, pp. 524-530, 1984.
[13] W. Nusselt, "Die Oberflachen Kondenastion des Wasserdamfes, " Zeitschrift des Vereunes Deurscher Ingenieure., vol. 60, no. 4, pp. 541-546 ; 569-575, 1916.
[14] A. Bejan, Entropy generation minimization, CRC Press, New York, (1996), 71-90.