Title: Second law analysis of simultaneous heat and mass transfer through non-grey gas radiation within a cylindrical annulus
Authors: Abir Sakly; Akram Mazgar; Faycal Ben Nejma
Addresses: Preparatory Institute for Engineering Studies of Monastir, University of Monastir, Unit of Ionized and Reactive Media Studies, Avenue Ibn Eljazar, Monastir 5019, Tunisia ' The Institute of Applied Sciences and Technology of Mahdia, Monastir University, Sidi Messaoud, 5111 Mahdia, Tunisia ' Preparatory Institute for Engineering Studies of Monastir, University of Monastir, Unit of Ionized and Reactive Media Studies, Avenue Ibn Eljazar, Monastir 5019, Tunisia
Abstract: A numerical computation is performed to analyse entropy generation due to heat and mass transfer through non-gray gas radiation and forced convection within a cylindrical annulus. The inner cylinder, covered by a thin water film, is assumed to be adiabatic, while the outer one is considered to be isothermal and dry. The conservation equations are solved by applying the finite volume method. The radiative part of this study is solved by the 'Ray Tracing' method through S4 directions in association with the "statistical narrow band correlated-k" model. The results showed that entropy generation increases with dry wall temperature, annulus width and the outer wall emissivity. It is found that the radiative entropy generated at walls presents a clear dominance compared to entropy generated due to heat conduction, gas radiation and mass diffusion. It is justified that using a thin water film offers greater potential for protecting the inner wall against overheating.
Keywords: entropy generation; heat and mass transfer; ray tracing; non-grey gas; SNBCK model; thermal radiation; cylindrical annulus.
International Journal of Exergy, 2017 Vol.24 No.2/3/4, pp.254 - 280
Received: 16 Nov 2016
Accepted: 11 May 2017
Published online: 30 Oct 2017 *