Estimation of entropy generation by heat transfer from a liquid in an enclosure to ambient

Abstract

This study outlines the estimation of entropy generation of a stored liquid-vapour combination. A salient feature of the present study is the incorporation of a separated flow model for the calculation of entropy generated by a diabatic two phase system. Equations of state corresponding to different thermodynamic equilibria are used for these calculations. Two distinct expressions are proposed for the determination of the total entropy generated by the diabatic saturated two phase system that comprise liquid and ullage regions. The dissipative energy losses in various liquid-ullage systems is quantified through the derived mathematical relations obtained for the overall entropy generated by the system. These developed expressions form the basis of an experimental determination of the entropy generation rate. A parametric study on temperature influencing entropy generation has been performed in the context of different thermal transport mechanisms. The influence of fill levels on entropy generation was also analysed by considering a low and an intermediate filling ratio. The study concluded the influence of central zone of thermodynamic equilibrium with maximum wall convection and minimum concentration gradient on the overall entropy generated by the system. References A. Bejan. A study of entropy generation in fundamental convective heat transfers. ASME J Heat Transfer, 101, 1979, 718--725. doi:10.1115/1.3451063 A. Bejan. Second law analysis in heat transfer. Energy, 5, 1980, 721--732. doi:10.1016/0360-5442(80)90091-2 S. Sarangi. and K. Chowdhury. On the generation of entropy in a counter flow heat exchanger. Cryogenics, 22, 1982, 63--65. doi:10.1016/0011-2275(82)90095-9 P. K. Nag and P. Mukherjee. Thermodynamic optimization of convective heat transfer through a duct with constant wall temperature. Int J. Heat and Mass Transfer, 30, 1987, 401--405. doi:10.1016/0017-9310(87)90128-1 A. Bejan A thermodynamic optimization of geometry in engineering flow systems. Exergy Int. Journal, 4, 2001, 269--277. doi:10.1016/S1164-0235(01)00028-0 V. D. Zimparov Extended performance evaluation criteria for enhanced heat transfer surfaces: heat transfer through ducts with constant heat flux. Int J. Heat and Mass Transfer, 44, 2001, 169--180. doi:10.1016/S0017-9310(00)00074-0 H. Abbassi Entropy generation analysis in a uniformly heated micro channel heat sink. Energy, 32, 2007, 1932--1947. doi:10.1016/j.energy.2007.02.007 F. J. Collado The law of stable equilibrium and the entropy-based boiling curve for flow boiling. Energy, 30, 2005, 807--819. doi:10.1016/j.energy.2004.04.007 J. V. C. Vargas and A. Bejan Thermodynamic optimization of the match between two streams with phase change. Energy, 25, 2000, 15--33. doi:10.1016/S0360-5442(99)00052-3 P. K. Nag Engineering Thermodynamics. Tata McGraw-Hill Publishing Company Limited, 2nd Edition, 1996. W. M. Rohsenow, J. P. Hartnett, Y. I. Cho, Hand book of Heat Transfer. McGraw-Hill New York,3rd Edition, 1988. D. Rakshit, R. Narayanaswamy, T. Truong, K. P. Thiagarajan An experimental study on the interface mass transfer governing thermodynamics of stored liquids. Proceedings of the 20th National and 9th International ISHMT-ASME Heat and Mass Transfer Conference, January 4--6, 2010, Mumbai India. C. Balaji, M. Hˆlling, H. Herwig Entropy generation minimization in turbulent mixed convection flows. International Communications in Heat and Mass Transfer, 34, 2007, 544--552. doi:10.1016/j.icheatmasstransfer.2007.01.015 F. P. Incropera, D. P. Dewitt, T. L. Bergmen, A. S. Lavine Introduction to Heat Transfer. John Willey and Sons, 5th Edition, 2005. P.E. Liley, Steam Tables in SI Units, private communication. School of Mechanical Engineering, Purdue University, West Lafayette, IN., 1984. V. V. Malyshev and E. P. Zlobin Evaporation of liquid hydrocarbons in heated closed containers. Translated from Inzheneruo-Fizicheskii Zhurnal, 23, 4, 1972, 701--708. doi:10.1007/BF00835847