Numerical study of natural convection of Bingham fluid using a flexible fin
Authors: Hanaa Derraz, Bouzit Mohamed, Mokhefi Abderrahim, Bencherif Atika, Meriem Toumi
Volume 11, Issue 2, Paper No. 110202
Abstract
This research focuses on the analysis of the flow and heat transfer inside a square cavity containing a Bingham plastic fluid. The cavity undergoes heating on its left side, where a flexible and elastic fin is positioned at the center of this heated wall. Cooling takes place on the right side of the cavity, while the upper and lower walls are well-insulated. The equations governing the complex interaction between the fluid and the flexible fin are accurately solved using an arbitrary Lagrangian-Eulerian approach, in conjunction with the finite element methodology. This study concentrates on the impact of the flexible fin on heat transfer in the context of unsteady natural convection of a complex fluid with a yield stress inside a square cavity. The considered parameters include the variation of the Rayleigh number in the range of 103 to 105, the modification of the elasticity modulus between 5×1010 and 5×1011, the fin length (Lc) from 0.004 to 0.0073, the Prandtl number (Pr) from 0.71 to 100, and the variation of the Bingham number from 0 to 20. To provide a comprehensive understanding of the observed thermal and fluidic phenomena, results will be displayed in the form of isothermic contours and streamlines, accompanied by Nusselt number (Nu) and maximum stress ( ) curves. Observations indicate a significant improvement in the Nusselt number in the absence of a yield stress (Bn=0), reaching its maximum at (Ra = 105). Conversely, the variation of the elasticity modulus shows negligible influence. As the yield stress (Bn) increases, it begins to dominate the flow by nullifying the buoyancy-induced current, reaching a constant value for (Bn=20), corresponding to the conduction limit.
Keywords: Natural convection; Bingham plastic fluid; FSI; Heat transfer; Nusselt number
110202 Hanaa