Aspect ratio variation influence in minimizing entropy production generated by buoyancy driven flow of Newtonian fluid in L-shaped enclosure

Minimizing entropy generation boosts the efficacy of thermal engineering systems by reducing energy losses. This method maximizes fuel cells, nuclear, and geothermal reactors, electronic heating and cooling, photovoltaic storage of energy, and processing food. Entropy control is essential for contemporary heat conveyance uses because it enhances efficiency, sustainability, and saving energy. Thus, this work presents a detailed investigation of thermal fluidic transmission and entropic fluctuations caused by enclosure aspect ratio change in naturally convective water flow in an L-shaped chamber. Conservation rules are used to represent an issue in dimensional governing equations. After that, variables make constitutive equations dimensionless. The finite element method (FEM) is used in COMSOL Multiphysics to solve the issue. Graphs show viscous and thermal entropy versus flow control settings. Nusselt number and total entropy are calculated against various factors. Comparing current data to published research ensures accuracy. A change in step height produces more total entropy than a change in width. After that, viscous entropy decreases as Rayleigh number ( Ra ) increases, but thermal entropy increases. Additionally, thermal entropy outperforms viscous entropy for low irreversibility ratio parameters. The study suggests that temperature gradients contribute to total entropy at low Ra levels, whereas viscous forces contribute at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mi>Ra</mml:mi> <mml:mo>&gt;</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> . Nusselt number (6.0955) and total entropy (1033.9) peak at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mi>Pr</mml:mi> <mml:mo>=</mml:mo> <mml:mn>7</mml:mn> <mml:mo>.</mml:mo> <mml:mn>0</mml:mn> </mml:mrow> </mml:math> . When <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mi>ϕ</mml:mi> <mml:mo>=</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>3</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> , total entropy reaches its maximum value 70.