首页|Numerical study of free surface axisymmetric jet impinging on a heated flat surface utilizing high concentration SiO2 nanofluid
Numerical study of free surface axisymmetric jet impinging on a heated flat surface utilizing high concentration SiO2 nanofluid
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NSTL
Elsevier
Background: A comprehensive numerical study is presented to investigate the heat transfer and fluid flow characteristics between a vertical free surface jet and a horizontal heated plate. Methods: The jet was made up of water-SiO2 nanofluid with an average particle size of 8 nm that was delivered from a 6 mm nozzle diameter. The numerical model covered a wide range of jet Reynolds numbers up to 31,800, five nanoparticle volume fractions of 0, 2.5, 4.5, 6.5, and 8.5%, five values of the nozzle to plate aspect ratios (z/ d = 0.5, 1, 2, 4, and 8), and plate radius to jet diameter ratio (r/d) of 12.5. Two-dimensional continuity, momentum, and energy equations are discretized with commercial finite volume software (ANSYS Fluent 15) under the v2f turbulence model. The numerical model has been verified through the comparison between its predicted results and those obtained from previous experimental published work. Significant findings: The results were presented graphically in the form of free jet interface thickness, radial velocity profiles, turbulence intensity profiles, and local and average Nusselt numbers on the heated plate. The results showed that the improvement of the average Nusselt number increases with the volume fraction and Reynolds number. Therefore, the utilization of SiO2 nanoparticles can significantly provide the improvement of the average Nusselt number up to 66.02%, for a volume fraction of 8.5% compared to pure water. Also, the average Nusselt number is slightly influenced by the nozzle to plate aspect ratio (0.5 < z/d < 4). Finally, a new heat transfer correlation for the average Nusselt number has been proposed. The new correlation presents the average Nusselt number as a function of Reynolds number, Prandtl number, nanoparticle volume fraction, plate to jet diameter ratio, and nozzle to plate aspect ratio.
NSTL
Elsevier
