0
Research Papers: Gas Turbines: Combustion, Fuels, and Emissions

Flame Structure and Combustion Capability of Non-Premixed Rifled Nozzles

[+] Author and Article Information
Kuo C. San

Department of Aircraft Engineering,
Air Force Institute of Technology,
Kaohsiung, Taiwan 820, China
e-mail: d90543001@ntu.edu.tw

Shun C. Yen

Department of Mechanical and Mechatronic Engineering,
National Taiwan Ocean University, Keelung,
Taiwan 202, China

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the Journal of Engineering for Gas Turbines and Power. Manuscript received August 10, 2012; final manuscript received October 27, 2012; published online June 10, 2013. Assoc. Editor: Joseph Zelina.

J. Eng. Gas Turbines Power 135(7), 071501 (Jun 10, 2013) (9 pages) Paper No: GTP-12-1325; doi: 10.1115/1.4024060 History: Received August 10, 2012; Revised October 27, 2012

The target of this study is to promote combustion capability using a novel rifled nozzle which was set at the outlet of a conventional (unrifled) combustor. The rifled nozzle was utilized to adjust the flow swirling intensity behind the traditional combustor by changing the number of rifles. The rifle mechanism enhances the turbulence intensity and increases the mixing efficiency between the central-fuel jet and the annular swirled air-jet by modifying the momentum transmission. Specifically, direct photography, Schlieren photography, thermocouples, and a gas analyzer were utilized to document the flame behavior, peak temperature, temperature distribution, combustion capability, and gas-concentration distribution. The experimental results confirm that increasing the number of rifles and the annular swirling air-jet velocity (ua) improves the combustion capability. Five characteristic flame modes—jet-flame, flickering-flame, recirculated-flame, ring-flame and lifted-flame—were obtained using various annular air-jet and central fuel-jet velocities. The total combustion capability (Qtot) increases with the number of rifles and with increasing ua. The Qtot of a 12-rifled nozzle (swirling number (S) = 0.5119) is about 33% higher than that of an unrifled nozzle. In addition, the high swirling intensity induces the low nitric oxide (NO) concentration, and the maximum concentration of NO behind the 12-rifled nozzle (S = 0.5119) is 49% lower than that behind the unrifled nozzle.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

Experimental setup

Grahic Jump Location
Fig. 2

Variations of swirl number (S) against the annular-jet velocity (ua)

Grahic Jump Location
Fig. 3

Photographs of flame configurations for a unrifled nozzle at (a) ua = 0 m/s, (b) ua = 0.23 m/s, (c) ua = 0.42 m/s, (d) ua = 1.22 m/s, (e) ua = 1.98 m/s, and (f) ua = 2.16 m/s with a constant uc of 2.5 m/s. Shuttle speed = 1/2000 s.

Grahic Jump Location
Fig. 4

Distribution of characteristic flame modes

Grahic Jump Location
Fig. 5

Flame patterns visualized using the Schlieren photography when uc = 2.5 m/s

Grahic Jump Location
Fig. 6

Radial-temperature distributions along the axial positions at uc = 2.5 m/s. (a)–(c): ua = 0.23 m/s and (d)–(f) ua = 2.16 m/s.

Grahic Jump Location
Fig. 7

Temperature distributions along the x-axis at uc = 2.5 m/s and 0 ≤ ua ≤ 2.16 m/s

Grahic Jump Location
Fig. 8

Variations of nondimensional peak-temperature coordinate (xp.t./D) versus ua when uc = 2.5 m/s

Grahic Jump Location
Fig. 9

Variations of combustion capability (Q) versus x/D for various ua when uc = 2.5 m/s. (a) Behind an unrifled nozzle, (b) behind a 6-rifled nozzle and (c) behind a 12-rifled nozzle.

Grahic Jump Location
Fig. 10

Total combustion capability (Qtot) versus ua when uc = 2.5 m/s

Grahic Jump Location
Fig. 11

Variations of radial-concentrations at x/D = 3.75 when uc = 2.5 m/s. (a)–(c) ua = 0.23 m/s and (d)–(f) ua = 2.16 m/s.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In