AN ANALYSIS OF THE LIQUID FILMS BREAK-UP USING THE COMPUTER VISION TECHNIQUE
DOI:
https://doi.org/10.14311/AP.2021.61.0253Keywords:
Coarse droplet, liquid film, steam turbineAbstract
The aim of this paper is to introduce a novel approach for analysing the droplet formation in a transonic flow. The method suggested in this work is based on the combination of the measured data from the wind tunnel by an optical measurement and image processing. A new wind tunnel was developed for the study of the liquid film atomization at high speed flows similar to ones that can be found in steam turbines. The coarse droplets in steam turbines are formed from the liquid films on the blades and inner casings. The coarse droplets formed on the stator blades don´t follow the bulk flow and collide with the following moving blades. These collisions cause erosion and corrosion processes, which have an unfavourable effect on the reliability and the efficiency of the low pressure stages of steam turbines. The tunnel is equipped with a standard instrumentation for the measurement of the flow properties and for the analysis of the size distribution of the droplets. Two measurement methods were used for the measurement of the size of the droplets, photogrammetry and light scattering. In this paper, the image processing of the captured images is discussed. The images were taken by a camera with a telecentric lens. The paper contains an assessment of three image processing methods used for the measurement of the droplet distribution by the light extinction. Moreover, the formation of the droplets is captured on the trailing edge of the profile in the flow. The results bring a new view on the formation of droplets at high speeds.
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References
Z. Farago, N. Chigier. Parametric experiments on coaxial airblast jet atomization. In ASME 1990 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers Digital Collection, 1990. doi:10.1115/90-GT-081.
G. Gyarmathy, H. Meyer. Spontane Kondensation, VDI-Forschungsheft Verein Deutscher Ingenieure 508, chap. Part 2: Versuche über den Einfluß der Entspannungsschnelligkeit auf die Nebelbildung in übersättigtem Wasserdampf, p. 31–48. VDI-Verlag, Düsseldorf, 1965.
V. Petr, M. Kolovratník. Wet steam energy loss and related Baumann rule in low pressure steam turbines. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 228(2):206 – 215, 2014. doi:10.1177/0957650913512314.
O. Bartoš, X. Cai, M. Kolovratník. A detection of the coarse water droplets in steam turbines. In EPJ web of conferences, EFM13 – Experimental Fluid Mechanics 2013, vol. 67, p. 02005. 2014. doi:10.1051/epjconf/20146702005.
M. Kolovratník, O. Bartoš. CTU Optical probes for liquid phase detection in the 1000 MW steam turbine. In EPJ Web of Conferences, EFM14 – Experimental Fluid Mechanics 2014, vol. 92, p. 02035. 2015. doi:10.1051/epjconf/20159202035.
M. Kolovratník, J. Hrubý, V. Ždímal, et al. Nanoparticles found in superheated steam: a quantitative analysis of possible heterogeneous condensation nuclei. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 228(2):186 – 193, 2014. doi:10.1177/0957650913512816.
L. Mešt’anová, O. Bartoš. A study of the coarse water droplets formation in the nozzle. In EPJ Web of Conferences, EFM18 – Experimental Fluid Mechanics 2018, vol. 213, p. 02058. 2019. doi:10.1051/epjconf/201921302058.
O. Bartoš, P. Pavlícek, L. Mešt’anová. An experimental study of the coarse droplets formation. In AIP Conference Proceedings, vol. 2189, p. 020002. AIP Publishing LLC, 2019. doi:10.1063/1.5138614.
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Copyright (c) 2021 Lucie Měšťanová, Ondřej Bartoš
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