Effect of the Presence of Semi-circular Cylinders on Heat Transfer From Heat Sources Placed in Two Dimensional Channel

	Effect of the Presence of Semi-circular Cylinders on Heat Transfer From Heat Sources Placed in Two Dimensional Channel
Tikrit Journal of Engineering Sciences
Article 1, Volume 19, Issue 4, 2012, Pages 24-45 PDF (0 K)
Abstract
The effect of a semi-circular cylinders in a two dimensional channel on heat transfer by forced convection from two heat sources with a constant temperature has been studied numerically. Each channel contains two heat sources; one on the upper surface of the channel and the other on the lower surface of the channel. There is semi-circular cylinder under the source in upper surface and there is semi-circular cylinder above the source in lower surface. The location of the second heat source with its semi-cylinder has been changed and keeps the first source with its semi- cylinder at the same location. The flow and temperature field are studied numerically with different values of Reynolds numbers and for different spacing between the centers of the semi-cylinders. The laminar flow field is analyzed numerically by solving the steady forms of the two-dimensional incompressible Navier- Stokes and energy equations. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations, which discretized by finite volume method, body fitted coordinates are used to represent the complex channel geometry accurately, and grid generation technique based on elliptic partial differential equations is employed. SIMPLE algorithm is used to adjust the velocity field to satisfy the conservation of mass. The range of Reynolds number is (Re= 100 – 800) and the range of the spacing between the semi-cylinders is(1-4) and the Prandtl number is 0.7. The results showed that increasing the spacing between the semi-cylinders increases the average of Nusselt number of the first heat source for all Reynolds numbers. As well as the results show that the best case among the cases studied to enhance the heat transfer is when the second heat source and its semi-cylinder located on at the distance (S=1.5) from the first half of the cylinder and the Reynolds number is greater than (Re ≥ 400) because of the separation behind of the first semi-cylinder where it works to reduce the area of section flow, and this is leading to increase the speed and thus increases the rate of heat transfer. A comparison of numerical results agrees well with published results.

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