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Effects of Aspect Ratio and Obstacle Geometry Size on the Thermal Performance of Air inside a Rectangular Cavity

Corresponding Author : Mostafa Rafid (rafid-mee@sust.edu)

Authors : S. Alam (s.alam.dip04@gmail.com), S. M. Prottoy (smprottoy004@gmail.com), Mostafa Rafid (rafid-mee@sust.edu), M. Mustafizur Rahman (mmustafizurrahman@math.buet.ac.bd)

Keywords : Cavity, Nusselt Number, Heat Transfer, Richardson Number, Bulk Fluid temperature

Abstract :

In this numerical study, the authors investigated the effect of varying the aspect ratio of a rectangular cavity on mixed convective flow and heat transfer within the cavity with a solid square obstacle in the middle. Both the top and bottom cavity walls are adiabatic. The Left and right vertical walls have a uniform-temperature heat source and sink. The study is done by altering the size of the obstruction and aspect ratio of the rectangular cavity at Richardson numbers ranging from 0.0 to 5.0, Prandtl numbers, Pr = 0.71, and Reynolds numbers, Re = 100. The variations of the Nusselt number and bulk fluid temperature are also presented to show the overall heat transfer

characteristics inside the cavity. The obstruction dimension governed the isotherm lines, whereas the cavity space influenced the streamlines. Furthermore, because the left side wall is the heat source and the air inlet is at the bottom, increasing Richardson numbers, which indicate stronger buoyant force flows, resulted in better thermal performance and higher Nusselt numbers. Also, higher aspect ratios and smaller obstacle dimensions resulted

in more available air space inside the cavity, that reduced Nusselt numbers and bulk fluid temperatures. Finally, a strong correlation between the Nusselt number and bulk fluid temperature was hypothesized.

Published on March 28th, 2025 in Volume 5 (Special Issue), Mechanical, Manufacturing & Industrial Engineering