Litvinov I., Sharaborin D., Shtork S., Alekseenko S.

IVAN V. LITVINOV, Research Engineer, Institute of Thermophysics SB RAS; Post Graduate Student, Novosibirsk State University, Novosibirsk, Russia. 1, Lavrentiev Av., Novosibirsk, Russia, 630090, e-mail: litvinov@itp.nsc.ru 
DMITRIJ K. SHARABORIN, Research Engineer, Institute of Thermophysics SB RAS; Employee, Novosibirsk State University, Novosibirsk, Russia. 1, Lavrentiev Av., Novosibirsk, Russia, 630090, e-mail: sharaborin.d@gmail.com 
SERGEI I. SHTORK, PhD, Head of Laboratory, Institute of Thermophysics SB RAS; Employee, Novosibirsk State University, Novosibirsk, Russia. 1, Lavrentiev Av., Novosibirsk, Russia, 630090, e-mail: shtork@itp.nsc.ru 
SERGEI V. ALEKSEENKO, Corresponding Member, RAS, Director, Institute of Thermophysics SB RAS; Professor, Novosibirsk State University, Novosibirsk, Russia. 1, Lavrentiev Av., Novosibirsk, Russia, 630090, e-mail:aleks@itp.nsc.ru 

Application of a 3-C Stereo-PIV system for measurement of parameters of precessing helical vortex in a highly swirling flow

The article presents the experimental work dealing with the determination of the parameters of precessing the helical vortex emerging at the exit of a tangential swirler (the outlet nozzle diameter is 52 mm, the geometrical swirl number is 2.4). The experiments were carried out at highly turbulent flow conditions when non-dimensional precession frequency did not depend on the Reynolds number. The time-averaged and phase-averaged velocity distributions were obtained through the Stereo-PIV method using the pressure pulsations in the acoustic field of the swirling flow as a reference signal. The parameters of the helical vortex structure were obtained from the time-averaged velocity distributions as well as from the phase-averaged ones. The obtained parameters were employed as source data to calculate the precession frequency basing on the analytical theory. The study reveals that the accuracy of the precession frequency calculation when using the phase-averaged data makes up about 1 per cent and about 10 per cent when using the time-averaged data. In the latter case, the calculation precision may be considered as quite appropriate when carrying out engineering calculations and estimating the precessing vortex parameters. Such estimation may require less time and be less costly.

Key words: precessing vortex, helical vortex, flow pulsations.

REFERENCE 

1. Abdurakipov S.S., Dulin V.M., Markovich D.M., Hanjalic K. Expanding the Stability Range of a Lifted Propane Flame by Resonant Acoustic Excitation. Combust. Sci. Technol. 2013(185):1644-1666.

2. Alekseenko S.V., Kuibin P.A., Okulov V.L. Theory of concentrated vortices: An introduction. Berlin, Springer-Verlag Berlin Heidelberg, 2007, 488 p.

3. Alekseenko S.V., Kuibin P.A., Okulov V.L., Shtork S.I. Helical vortices in swirl flow. J. Fluid Mech. 1999(382):195-243.

4. Ceglia G., Discetti S., Ianiro A., Michaelis D., Astarita T., Cardone G. Three-dimensional organization of the flow structure in a non-reactive model aero engine lean burn injection system. Exp. Therm. Fluid Sci. 2014(52):164-173.

5. Derksen J.J., Van den Akker H.E.A. Simulation of vortex core precession in a reverse-flow cyclone. AIChE J. 2000(46);7:1317-1331.

6. Gronald G., Derksen J.J. Simulating turbulent swirling flow in a gas cyclone: A comparison of various modeling approache. Powder Technol. 2011(205);1–3:160-171.

7. Gupta K., Lilley D.G., Syred N., Beer J.M. Combustion in swirling flows: A review. Combust. Flame. 1974(23).

8. Gupta K., Lilley D.G., Syred N. Swirl Flows. Kent., Abacus Press., 1984.

9.  Institute of Thermophysics SB RAS. Actual flow Manual. URL: http://www.polis-instruments.ru .

10. Kuibin P.A., Okulov V L. Self-induced motion and asymptotic expansion of the velocity field in the vicinity of a helical vortex filament. Phys. Fluids. 1998(10):607-614.

11. Litvinov I.V., Shtork S.I., Kuibin P.A., Alekseenko S.V., Hanjalic K. Experimental study and analytical reconstruction of precessing vortex in a tangential swirler. Int. J. Heat Fluid Flow. 2013(42):251-264.

12.  Martinelli F., Olivani A., Coghe A. Experimental analysis of the precessing vortex core in a free swirling jet. Exp. Fluids 2007(6);42:827-839.

13.  Moeck J.P., Bourgouin J., Durox D., Schuller T., Candel S. Nonlinear interaction between a precessing vortex core and acoustic oscillations in a turbulent swirling flame. Combust. Flame. 2012(159);8:2650-2668.

14. Oberleithner K., Sieber M., Nayeri C.N., Paschereit C.O., Petz C., Hege H.-C., Noack B.R., Wygnanski I. Three-dimensional coherent structures in a swirling jet undergoing vortex breakdown: stability analysis and empirical mode construction. J. Fluid Mech. 2011(679):383-414.

15. Pisarev G.I., Hoffmann A.C., Peng W., Dijkstra H.A. Large Eddy Simulation of the vortex end in reverse-flow centrifugal separators. Appl. Math. Comput. 2011(217);11: 5016-5022.

16. Prasad A.K., Jensen K. Scheimpflug stereocamera for particle image velocimetry in liquid flows. Appl. Opt. 1995(34):7092-7099.

17. Ranga Dinesh K.K.J., Kirkpatrick M.P. Study of jet precession, recirculation and vortex breakdown in turbulent swirling jets using LES. Comput. Fluids. 2009(38):1232-1242.

18. Shtork S.I., Cala C.E., Fernandes E.C. Experimental characterization of rotating flow field in a model vortex burner. Exp. Therm. Fluid Sci. 2007(31):779-788.

19.  Shtork S.I., Vieira N.F., Fernandes E.C. On the identification of helical instabilities in a reacting swirling flow. Fuel. 2008(87):2314-2321.

20. Syred N. A review of oscillation mechanisms and the role of the precessing vortex core (PVC) in swirl combustion systems. Prog. Energy Combust. Sci. 2006(32):93-161.

21.  Terhaar S., Oberleithner K., Paschereit C.O. Key parameters governing the precessing vortex core in reacting flows: An experimental and analytical study. Proc. Combust. Inst., 2015(35);3:3347-3354.

22. Tropea C., Yarin A.L., Foss J.F. (eds). Springer Handbook of Experimental Fluid Mechanics. Springer, Hellborg, 2007, 1585 p.

23. Winfield D., Cross M., Croft N., Paddison D., Craig I. Performance comparison of a single and triple tangential inlet gas separation cyclone: A CFD Study. Powder Technol. 2013(235):520-531.

24. Yazdabadi P.A., Griffiths A.J., Syred N. Characterization of the PVC phenomena in the exhaust of a cyclone dust separator. Exp. Fluids. 1994(17):84-95.

25.  Zaharov D.L., Krasheninnikov S.J., Maslov V.P., Mironov A.K. Investigation of unsteady processes, flow properties, and tonal acoustic radiation of a swirling jet. Fluid Dyn. 2014(49);1:51-62.