Wall shear rates and stagnation mass transfer on a plate in axisymmetric and cross impinging jets
2012
This article presents a study on the stagnation wall shear rate and mass transfer ofimpinging jets on a flat plate. The performance of a cross-shaped orifice nozzle was comparedwith a reference convergent circular nozzle having similar equivalent diameter. An array ofelectrodiffusion micro probes inserted into the plate was used for wall shear ratesmeasurements. Mass transfer in the impinging region was calculated from the measured wallshear rates for a Reynolds number around 5500 and over a range of streamwise distancesbetween the nozzle and the impinging plane within 1 to 5 nozzle equivalent diameters. Themost important observation in the present investigation is that the wall shear rates and the masstransfer in the impingement region of the cross-shaped orifice nozzle are up to 175% and 40%,respectively, higher than that of the convergent nozzle. The performance of the cross-shapedorifice jet is probably related to its particular vortex dynamics characteristic of the near exitregion. All the results confirm that the jet passive control enhance the mass transfer.
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