Numerical study of a round jet impinging on an axisymmetric grooved surface: effect of the groove size
A. Derdouri1, Z. Nemouchi1, A. Benhacine1, K. Abed-Meraim2, A. Sakout2
1Universite Freres Mentouri, Constantine 1, Algeria
2Universite de La Rochelle, La Rochelle, France
Keywords: axisymmetric impinging jet, corrugated surface, square grooves, SST k-П‰ turbulence model, Nusselt number
Abstract
The effects of the groove size on the dynamical and thermal behavior in a round jet impinging on an axisymmetric corrugated surface are investigated numerically. The geometry is similar to that considered by Sagot et al. (2010, Int. J. Therm. Sci., 49, 1026-1030) in their experimental study. Three side lengths of the square grooves are tested, one eighth, one quarter and three eighths of the jet diameter. A comparison is made with the flat plate case. The nozzle-to-plate distance is 2D, the Reynolds number is Re = 23000 and the ratio of the plate-radius to nozzle-diameter is R/D = 6. The SST k-ω model is employed to take account of turbulence effects. An attempt is made to understand thoroughly how key parameters such as mean velocity, turbulent kinetic energy and temperature fields can influence the heat transfer performance. The local normal-to-wall temperature gradient and thus the local heat flux through the fluid/wall interface are strongly dependent on these parameters. This justifies our interest in analyzing the distributions of such determining factors in the wall jet and, particularly, in the recirculating zones inside the cavities. Their imprints on the friction coefficient and the local and averaged values of the Nusselt number are highlighted.
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