Experimental Study on Coaxial Swirling Flows
The experimental investigation of a swirling jet and an annular swirling stream issuing from coaxial cylinders is presented. The objective is to contribute to the research on the combined flow field close to vortex breakdown conditions. The two swirling water streams are interacting in the extension of the outer cylinder. Swirl is generated by two rotating impellers, located in the inner tube and the annular duct, just before the merging of the two streams. Controlled flow parameters comprise the flow rates of the streams and the angular velocities of the impellers. The flow field is monitored by means of Stereoscopic 3D-PIV, providing the velocity components on an axial, central plane. Four typical test cases were investigated comprising four combinations of inlet conditions. Two dimensionless numbers were utilized to interpret the experimental results, a modified Rossby number and the velocity ratio ζ, along with the Reynolds numbers of the internal and annular stream, respectively. The most important coherent structure developed, is a recirculation region formed downstream of the exit of the internal swirl nozzle. A bubble type vortex breakdown occurs when the appropriate flow conditions are applied. The alterations of the flow field were discussed with respect to the changes of the inlet conditions. The flowrates of the two streams and the combined swirl strength applied through the rotating impellers appear to be crucial for the onset of the vortex breakdown. Comparisons were drawn with previous work.
Copyright © 2020 Praise Worthy Prize - All rights reserved.
R. Rotunno, The fluid dynamics of tornadoes, Annual Review of Fluid Mechanics, Volume 45, 2013, pp 59-84.
P. A. Yazdabadi, A. J. Griffiths, N. Syred, Characterization of the PVC phenomena in the exhaust of a cyclone dust separator, Experiments in Fluids, June 1994, Volume 17, Issue 1–2, pp 84–95.
S. Skripkin, M. Tsoy, P. Kuibin, S. Shtork, Swirling flow in a hydraulic turbine discharge cone at different speeds and discharge conditions, Experimental Thermal and Fluid Science, 2019, 100:349–359
K. Rajamanickam, S. Roy, S. Basu, Novel fuel injection systems for high-speed combustors, Droplets and Sprays, 2018, pp. 183–216
O. Lucca-Negro, T. O' Doherty, Vortex breakdown: a review, Progress in Energy and Combustion Science, Vol. 27, n. 4, pp. 431-481, 2001.
A. K. Gupta, D. G. Lilley, N. Syred, Swirl Flows, (1st Edition, Abacus Press, Tunbridge Wells, England, 1984).
T. B. Benjamin, Theory of the vortex breakdown phenomenon, J. Fluid Mech, 1962, Volume 14, Issue 4, December 1962, pp. 593-629
G. K. Batchelor, An Introduction to Fluid Dynamics, Cambridge University Press, 1967
N. C. Lambourne, D. W. Bryer, The Bursting of Leading-Edge-Vortices Some Observations and Discussion of the Phenomenon, London HMSO 1962
D. H. Peckham, S. Atkinson, Preliminary results of low speed wind tunnel tests on a Gothic wing of aspect ratio 1.0, Royal Aircraft Establishment, Technical note AERO, Vol. 2504, 1957.
S. Leibovich, The Structure of Vortex Breakdown, Annual Review of Fluid Mechanics, Vol. 10, pp. 221-246, 1978.
Y. Wang, X. Wang, V. Yanga, Evolution and transition mechanisms of internal swirling flows with tangential entry, Physics of Fluids, Volume 30, December 2017
M. Escudier, Vortex breakdown: Observations and explanations, Progress in Aerospace Sciences, Vol. 25, n. 2, pp. 189-229, 1988.
F. H. Champagne, S. Kromat, Experiments on the formation of a recirculation zone in swirling coaxial jets, Experiments in Fluids, 2000, Volume 29, Issue 5, pp 494–504
T. Ivanic, E. Foucault, J. Pecheux, Dynamics of swirling jet flows, Experiments in Fluids 35 (2003) 317–324
A. Giannadakis, A. Naxakis, A. Romeos, K. Perrakis, T. Panidis, An experimental study on a coaxial flow with inner swirl: vortex evolution and flow field mixing attributes, Aerospace Science and Technology, Volume 94, November 2019, 105373
M. D. Le, Effects of single- and dual-blockage disks on swirling coaxial jets at high annulus Reynolds numbers, Heat and Mass Transfer, Volume 56, Issue 5, p.1463-1473, December 2019.
K. Rajamanickam, S. Basu, Insights into the dynamics of conical breakdown modes in coaxial swirling flow field, J. Fluid Mech. (2018), vol. 853, pp. 72-110, 25 October 2018.
Naxakis, A., Perrakis, K., Panidis, T., Experimental Study on Swirling Jets, (2018) International Review of Mechanical Engineering (IREME), 12 (6), pp. 533-539.
- There are currently no refbacks.
Please send any question about this web site to email@example.com
Copyright © 2005-2021 Praise Worthy Prize