Issue |
MATEC Web Conf.
Volume 345, 2021
20th Conference on Power System Engineering
|
|
---|---|---|
Article Number | 00006 | |
Number of page(s) | 7 | |
DOI | https://doi.org/10.1051/matecconf/202134500006 | |
Published online | 12 October 2021 |
Turbulent jet stability increased by ribs inside the nozzle – Stereo PIV measurement one diameter past the nozzle
1 University of West Bohemia in Pilsen, Univerzitní 22, Pilsen, Czech Republic
2 Intstitute of Thermomechanics of the Czech Academy of Sciences, Dolejškova 5, Prague, Czech Republic
* Corresponding author: dudad@kke.zcu.cz
We observe that decreasing the inner nozzle surface by adding longitudinal ribs increases the jet stability in terms of the amount of turbulent kinetic energy in the near shear layer. We try to explain our observation as a stabilization effect of secondary flow vortices emerging in the corners of the ribs. These stream-wise vortices damage the development of larger-scale structures in the near shear layer. This explanation is supported by autocorrelation function of the stream-wise velocity component, which displays slightly smaller integral length-scale in the case with ribs than in the case of smooth nozzle. The experiment is performed at Reynolds number 2.2 × 105 (based on the nozzle diameter 50 mm); the Stereo-PIV (Particle Image Velocimetry) measurement takes place at the plane perpendicular to the jet axis one diameter past the nozzle exit. Optical 3D scanner controls the real nozzle geometry. This article presents preliminary measurement at single position and single velocity only; further exploration of this problem is needed.
© The Authors, published by EDP Sciences, 2021
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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