Investigation of Magneto-Convection Characteristics in A Sudden Expanding Channel with Convex Surface Geometry Under Thermally Developing Flow Conditions

Abstract

<title>Abstract</title> <p>The current study presents a novelty with focusing on the magnetic field effect on a sudden expansion tube with expansion ratio, total length, and pitch length of the dimpled fin is 2.5, 1500 <italic>mm</italic>, and 3.0, respectively. The magnetizable <italic>Fe</italic>_{<italic>3</italic>}<italic>O</italic>_{<italic>4</italic>}<italic>/H</italic>_{<italic>2</italic>}<italic>O</italic> Ferrofluid with different nanoparticle volumetric concentrations (<italic>φ</italic> = 1.0<italic>%</italic> and 2.0<italic>%</italic>) were used as a heat transfer fluid, and magnetohydrodynamic effects were elaborately investigated in this study. The numerical analysis was conducted under laminar flow regime and the <italic>DC</italic> magnetic field (<italic>B</italic>_{<italic>0</italic>} = 0.03<italic>T</italic>, 0.05<italic>T</italic>, 0.3<italic>T</italic>, and 0.5<italic>T</italic>). The present study provided a comprehensive investigation, which presented the thermo-hydraulic performance of difference dimpled fins, <italic>Fe</italic>_{<italic>3</italic>}<italic>O</italic>_{<italic>4</italic>}<italic>/H</italic>_{<italic>2</italic>}<italic>O</italic> Ferrofluid, and magnetic field. According to the results, dimple fins showed the best increment within heat transfer enhancement techniques. The heat transfer enhancement rate of the dimple tube and <italic>Fe</italic>_{<italic>3</italic>}<italic>O</italic>_{<italic>4</italic>}<italic>/H</italic>_{<italic>2</italic>}<italic>O</italic> Ferrofluid were respectively acquired as 22.62<italic>%</italic> and 5.43<italic>%</italic>-6.28<italic>%</italic> (<italic>φ</italic> = 1.0<italic>%</italic> and 2.0<italic>%</italic>). When dimpled fin and <italic>Fe</italic>_{<italic>3</italic>}<italic>O</italic>_{<italic>4</italic>}<italic>/H</italic>_{<italic>2</italic>}<italic>O</italic> Ferrofluid were used, the increment in Performance Evaluation Criteria was calculated as 21.31<italic>%</italic> and 4.85<italic>%</italic>-9.79<italic>%</italic> (<italic>φ</italic> = 1.0<italic>%</italic> and 2.0<italic>%</italic>). Although the highest average Nusselt number was obtained at <italic>B</italic>_{<italic>0</italic>} = 0.5<italic>T</italic>, the highest performance evaluation criteria were detected at <italic>B</italic>_{<italic>0</italic>} = 0.3<italic>T</italic> due to the friction factor showing an increment.</p>