Natural convection heat transfer in enclosure with uniformly heated Inner elliptic cylinder and outer square cylinder

الملخص EN

Experimental and numerical simulation study for natural convection heat transfer formed by uniformly heated inclined elliptical cylinder concentrically located in an enclosed square cylinder subjected to the ambient have been investigated.

Experiments have been carried out for Rayliegh number ranges from 0.9 × 106 to 3.3 × 106.

The enclosure angles of inclination are f = 0o (horizontal), 45o (inclined), and 90o (vertical), and for axis ratio of elliptic cylinder (minor / major = b / c) of 1 : 2, while the dimensions of outer square cylinder was 0.5 × 0.5 × 2 m.

A numerical simulation was conducted by using commercial Fluent CFD code to investigate the steady laminar natural convective heat transfer for air between a heated elliptic cylinder and its square enclosure.

It covered a range of hydraulic radius ratios (HRR) of 1.97, 2.62, and 3.93 and for orientation angles j = 0o (the major axis is vertical), 30o, 45o.

Two values of Rayligh number were taken : 0.9 × 106 and 3.3 × 106.

The experimental results showed that the heat transfer process improves as Rayliegh number increases and is better in f = 0o than other angles of inclination at the same heat input.

Theoretical results showed that the HRR, Rayligh number, and angle of orientation have significant effect on the physical behavior of stremlines and isotherms inside the equivalent annular gap.