Analysis of convective hybri‘d nanofluid in an oblique porous cavity with heated chamfers and internal obstacle

Abstract

Abstract Numerical simulation of thermo-convective flow under varying obstacles for analyzing heat transfer and entropy generation has emerged as an attractive research field for enhancing the performance of thermodynamic systems, particularly within porous media. This study investigates the entropy generation characterization and convective heat transport of hybrid nanofluid within a porous inclined cavity with heated chamfers. Two different cases of cooled internal obstacle are considered, namely, square obstacle (Case 1) and plus-shaped bar (Case 2). The mathematical model incorporates the continuity, momentum, and energy equations, which are nondimensionalized and solved via the finite volume approach. The complete mathematical model has been numerically implemented using a MATLAB house code at various values of flow parameters, such as Rayleigh number $$(10^3 \le {\text {Ra}} \le 10^6)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>3</mml:mn> </mml:msup> <mml:mo>≤</mml:mo> <mml:mtext>Ra</mml:mtext> <mml:mo>≤</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> , Darcy number $$(10^{-1} \le {\text {Da}} \le \ 10^{-5})$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> <mml:mo>≤</mml:mo> <mml:mtext>Da</mml:mtext> <mml:mo>≤</mml:mo> <mml:mspace/> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>5</mml:mn> </mml:mrow> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> , the volume fraction of hybrid nanoparticles $$(0 \le \phi \le 8\%)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:mn>0</mml:mn> <mml:mo>≤</mml:mo> <mml:mi>ϕ</mml:mi> <mml:mo>≤</mml:mo> <mml:mn>8</mml:mn> <mml:mo>%</mml:mo> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> , and cavity inclination angle $$(0^\circ \le \omega \le 180^\circ )$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mo>(</mml:mo> <mml:msup> <mml:mn>0</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> <mml:mo>≤</mml:mo> <mml:mi>ω</mml:mi> <mml:mo>≤</mml:mo> <mml:msup> <mml:mn>180</mml:mn> <mml:mo>∘</mml:mo> </mml:msup> <mml:mo>)</mml:mo> </mml:mrow> </mml:math> . The outcomes of the simulation were presented through isothermal contours and streamlines. Furthermore, the results for entropy generation have been monitored through the Bejan number. Based on the obtained outcomes, the square obstacle in the considered Case 1 is more effective in enhancing flow intensity and heat dispersion with reduced disturbance compared to the plus-shaped obstacle. An improvement in the Nusselt numbers was noted with an increase in the volume fraction, attaining $$42.2\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>42.2</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> for Case 1 and $$42.6\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>42.6</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> for Case 2. Under the same conditions, the presence of the square obstacle achieves a $$12\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>12</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> higher average Nusselt number than the presence of the plus-shaped obstacle, illustrating that obstacle geometry plays a decisive role in optimizing thermal performance within porous cavities.