Abstract
A two-dimensional solution of natural convection heat transfer in a trapezoidal enclosure using baffles attached to hot wall has been analyzed numerically. The vertical and inclined walls of the enclosure are isothermal while the bottom and top horizontal walls are insulated and the temperature of the vertical wall is higher than the temperature of the inclined wall. Governing equations are solved using the finite difference technique. The study included three cases: one baffle at position 0.5, two baffles at positions 0.2 and 0.5, and three baffles at positions 0.2, 0.4 and 0.6, in addition to Rayleigh number 10 3 , 10 4 and 10 5 and baffle length of 0.2, 0.3 and 0.4 used as governing parameters that are effective on heat transfer and fluid flow. Results for the mean Nusselt number, and contour maps of the streamlines and isotherms are presented. It is found that Nusselt number is an increasing with increasing in Rayleigh number while decreasing with increasing in the baffle length and number of baffles. Key words : Natural convection, Trapezoidal enclosure , Heat transfer , baffles
Highlights
Natural convection heat transfer in enclosures has been a topic for many studies found in the literature
The purpose of the present work is to studying the natural convection heat transfer inside a trapezoidal enclosure with a three cases, one, two and three baffles attached to hot wall while the inclined wall is cold
Figure (3, A-B-C) shows the effect of baffle length when the baffles are attached to active wall at Yf=0.5 for one baffle, 0.2 and 0.5 for two baffles and 0.2, 0.4 and 0.6 for three baffles at Rayleigh number Ra=104
Summary
Natural convection heat transfer in enclosures has been a topic for many studies found in the literature. In these studies, square, rectangular, inclined, slender and shallow cavities with various wall conditions have been considered extensively by different researchers. There are many industrial applications where the heat transfer through a fluid layer contained in an enclosure is desired to be controlled. The rate of heat transfer through a fluid layer in an enclosure may be controlled by attaching baffles to one of the active walls of the enclosure. Studying heat transfer through a fluid layer enclosed in a cavity with baffles attached to its wall(s) has value from practical as well as theoretical point of views. Baffles are used in flow channels to control the heat transfer rate across the channel walls [1]
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