University of Technology-IraqEngineering and Technology Journal1681-6900301920121101Natural Convection Heat Transfer in Enclosure with Uniformly Heated Inner Elliptic Cylinder and Outer square Cylinder343534566617210.30684/etj.30.19.12ENAkeel Abdullah MohammedJournal Article20121101Experimental and numerical simulation study for natural convection heat<br /> transfer formed by uniformly heated inclined elliptical cylinder concentrically<br /> located in an enclosed square cylinder subjected to the ambient have been<br /> investigated. Experiments have been carried out for Rayliegh number ranges from<br /> 0.9×106 to 3.3×106. The enclosure angles of inclination are f =0o (horizontal), 45o<br /> (inclined), and 90o (vertical), and for axis ratio of elliptic cylinder<br /> (minor/major=b/c) of 1:2, while the dimensions of outer square cylinder was<br /> 0.5×0.5×2 m. A numerical simulation was conducted by using commercial<br /> Fluent CFD code to investigate the steady laminar natural convective heat<br /> transfer for air between a heated elliptic cylinder and its square enclosure. It<br /> covered a range of hydraulic radius ratios (HRR) of 1.97, 2.62, and 3.93 and<br /> for orientation angles j = 0o (the major axis is vertical), 30o, 45o. Two<br /> values of Rayligh number were taken: 0.9×106 and 3.3×106. The experimental<br /> results showed that the heat transfer process improves as Rayliegh number<br /> increases and is better in f =0o than other angles of inclination at the same<br /> heat input. Theoretical results showed that the HRR, Rayligh number, and<br /> angle of orientation have significant effect on the physical behavior of<br /> stremlines and isotherms inside the equivalent annular gap.https://etj.uotechnology.edu.iq/article_66172_8d37d3eee98749065bf0ef368bb30243.pdf