Abstract
Flow momentum behind a conventional nozzle is modulated by four different bluff-body cones — non-rifled, 1-rifled, 2-rifled and 3-rifled cones. This novel rifled-cone swirl generator (RCSG) includes the blockage disc and rifled bluff-body cones. The rifled bluff-body cone transforms the axial momentum (or the axial velocity) into the angular momentum (or the tangential velocity). The swirling flow is enhanced by increasing the tangential velocity of central jet. In this investigation, the carbon-dioxide (CO2) is utilized as the index gas to determine the mixing index of RCSGs. Namely, the mixing index between the central CO2-jet and the annular air-jet is increased using the RCSGs. The cold-flow patterns behind the rifled bluff-body cones are visualized using the smoke-wire scheme. The cold-flow patterns are categorized as — jet-flow, single-bubble and dual-bubble modes. The jet-flow mode occurs at low u a . Additionally, the jet-flow and single-bubble modes are further classified as — Type-I and type-II sub-modes. The particle-image velocimetry (PIV) measures the cold-flow velocity vectors. The mixing levels of CO2 in the cold-flow modes are detected using a gas concentration analyzer.
Similar content being viewed by others
References
W. C. Reynolds, D. E., Parekh, P. J. D. Juvet and M. J. D. Lee, Bifurcating and blooming jets, Annual Review of Fluid Mechanics, 35 (2003) 295–315.
E. J. Gutmark and F. F. Grinstein, Flow control with noncircular jets, Annual Review of Fluid Mechanics, 31 (1999) 239–72.
J. Mi, G. J. Nathan and R. E. Luxton, Centreline mixing characteristics of jets from nine differently shaped nozzles, Experiments in Fluids, 28 (2000) 93–94.
T. Carmody, Establishment of the wake behind a disk, ASME Journal of Basic Engineering, 86 (1964) 869–882.
T. W. Davies and J. M. Beer, Flow in the wake of bluff-body flame stabilizers, Proc. of Thirteenth Symposium (Int.) on Combustion, The Combustion Institute, PA, (1971) 631–638.
D. F. G. Durao and J. H. Whitelaw, Velocity characteristics of the flow in the near wake of a disk, Journal of Fluid Mechanics. 86 (1978) 369–385.
R. W. Schefer, M. Namazian and J. Kelly, Velocity measurement in turbulent bluff-body stabilized flows, AIAA Journal, 32 (1994) 1844–1851.
W. G. Rose, A swirling round turbulent jet 1-mean-flow measurements, ASME Journal of Applied Mechanics, 29 (1962) 615–625.
J. P. Hartnett and E. R. G. Eckert, Experiment study of the velocity and temperature distribution in a high velocity vortex type flow, ASME Journal of Fluids Engineering, 79 (1957) 751–757.
A. W. Hübner, M. J. Tummers, K. Hanjalić and T. H. van der Meer, Experiments on a rotating-pipe swirl burner, Experimental Thermal and Fluid Science, 27(4) (2003) 481–489.
N. A. Chigier and J. M. Beer, Velocity and static pressure distributions in swirling air jets issuing from annular and divergent nozzles, ASME Journal of Fluids Engineering, 86 (1964) 788–798.
R. K. Cheng, Velocity and scalar characteristics of premixed turbulent flames stabilized by weak swirl, Combustion and Flame, 101(1–2) (1995) 1–14.
Y. M. Al-Abdeli and A. R. Masri, Recirculation and flowfield regimes of unconfined non-reacting swirling flows, Experimental Thermal and Fluid, 27(5) (2003) 655–665.
N. M. Kerr and D. Fraser, Swirl part 1: Effect on axisymmetrical turbulent jets, Journal of the Institute of Fuel, 38 (1965) 519–526.
W. A. Guttenfelder, M. W. Renfro, N. M. Laurendeau, J. Ji, G. B. King and J. P. Gore, Hydroxyl time series and recirculation in turbulent nonpremixed swirling flames, Combustion and Flame, 147(1–2) (2006) 11–21.
R. F. Huang and F. C. Tsai, Observations of swirling flows behind circular discs, AIAA Journal, 39(6) (2001) 1106–1112.
K. C. San and H. J. Hsu, Characteristics of flow and flame behavior behind rifled/unrifled nozzles, ASME Journal of Engineering for Gas Turbines and Power, 131 (2009) 051501.
T. J. Mueller, Flow visualization by direct injection, In R. J. Goldstein, Ed., Fluid Mechanics Measurements, 2nd Ed., Taylor & Francis, Washington DC, USA, (2000).
R. C. Flagan and J. H. Seinfeld, Fundamentals of air pollution engineering, Prentice-Hall, N. J., USA, (1988).
R. B. Abernethy, R. P. Benedict and R. B. Dowdell, ASME measurement uncertainty, ASME Journal of Fluids Engineering, 107 (1985) 161–164.
R. F. Huang and S. C. Yen, Axisymmetric swirling vortical wakes modulated by a control disc, AIAA Journal, 41(5) (2003) 888–896.
Author information
Authors and Affiliations
Corresponding author
Additional information
Recommended by Associate Editor Simon Song
Kuo-Ching San was born in Taichung, Taiwan, R.O.C., on June 28, 1969. He received the B.S. degree from Air Force Academy, Kaohsiung, R.O.C., in 1992; the M.S. degree from Polytechnic University, Brooklyn, NY, in 1997; and the Ph.D. from National Taiwan University, Taipei, R.O.C., in 2007. His research interests include the analysis of flow patterns on wing airfoil and flame behaviors on unconfined/non-premixed combustion.
Rights and permissions
About this article
Cite this article
San, K.C., Shih, C.L. & Yen, S.C. Cold-flow patterns behind novel rifled bluff-body cones. J Mech Sci Technol 28, 887–894 (2014). https://doi.org/10.1007/s12206-013-1156-x
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12206-013-1156-x