Swirling flames are used in many industrial applications, such as process furnaces, boilers, and gas turbines due to their excellent mixing, stability, emission, and burnout characteristics. The wide-spread use of swirl burners in the process and energy industries and, in particular, new concepts for the reduction of NOx emissions, raises the need for simple-to-use models for predicting lean stability limits of highly turbulent flames stabilized by internal recirculation. Based on recently published experimental data of the first author concerning the reaction structures of swirling flames operating near the extinction limit, different methods for predicting lean blow-off limits have been developed and tested. The aim of the investigations was to find stabilization criteria that allow predictions of blow-off limits of highly turbulent recirculating flames without the requirement for measurements in those flames. Several similarity criteria based on volumetric flow rates, burner size, and material parameters of the cold gases were found to be capable of predicting stability limits of premixed and (in some cases) nonpremixed flames at varying swirl intensities, burner scales and fuel compositions. A previously developed numerical field model, combining, a k–ε model with a combined “assumed-shape joint-PDF”/eddy-dissipation reaction model was also tested for its potential for stability prediction.

Issue Section:
Gas Turbines: Combustion and Fuels
Topics:
Flames, Stability, Swirling flow, Turbulence, Emissions, Boilers, Eddies (Fluid dynamics), Energy dissipation, Energy industry, Flow (Dynamics), Fuels, Furnaces, Gas turbines, Gases, Nitrogen oxides, Shapes
1.
Hoffmann
S.
, and
Lenze
B.
, “
Investigations Concerning Stability Mechanism of Unconfined Swirling Premixed Flames
,”
Archivum Combustionis
, Vol.
12
, No.
1–4
,
1992
, pp.
45
–
57
.
2.
Philipp, M., Hoffmann, S., Habisreuther, P., Lenze, B., and Eickhoff, H.,“Experimental and Numerical Study Concerning Stabilization of Strongly Swirling Premixed and Nonpremixed Flames,” 24th Symposium (Int.) on Comb., Pittsburgh, 1992, pp. 361–368.
3.
Philipp, M., “Experimentelle und theoretische Untersuchungen zum Stabilita¨tsverhalten von Drallflammen mit zentraler R¨ckstro¨mzone,” Ph. D. Thesis, Universita¨t Karlsruhe, 1991.
4.
Minx, E., “U¨ber die Stauscheibenstabilisierung turbulenter Diffusionsflammen an Brennern mit zentraler Brennstoff- und ringfo¨rmiger Luftzufuher,” Ph.D. Thesis, Universita¨t Aachen, 1969.
5.
Rawe, R., “U¨ber die Drallstabilisierung freibrennender, turbulenter Diffusionsflammen mit zentraler, radialer Gaszufuhr,” Ph. D. Thesis, Ruhr-Universita¨t Bochum, 1978.
6.
Prade, B., and Lenze, B., “Experimental Investigation in Extinction of Turbulent Non-Premixed Disk Stabilized Flames,” 24th Symposium (Int.) on Combustion, Sydney, Australia, July 5–12. 1992, The Combustion Institute, Pittsburgh, 1992, pp. 369–375.
7.
Glarborg, P., Kee, R. J., Grear, J. F., and Miller, J. A., “A Fortran Program for Modelling Well-Stired Reactors,” Sandia National Laboratories, Albuquerque, NM, Sandia Report Sand 86-8209, 1986.
8.
Miller
J. A.
, and
Bowman
C. T.
,
Prog. Energy Comb. Sci.
, Vol.
15
, No.
4
,
1989
, pp.
287
–
338
.
9.
Westbrook, C. K., and Dryer, F. L., “Simplified Reaction Mechanisms for the Oxidation of Hydrocarbon Fuels in Flames,” Combustion Sci. and Tech., Vol. 27, 1981.
10.
Leuckel, W., “Swirl Intensities, Swirl Types and Energy Losses of Different Swirl Generating Devices,” IFRF Doc No. G 02/a/16, Nov. 1967.
11.
Hoffmann, S., “Untersuchungen des Stabilisierungsverhaltens und der Stabilita¨atsghrenzen von Drallflammen mit innerer Ru¨ckstr;o¨mzone,” Ph.D. Thesis, Universita¨t Karlsruhe, 1994.
12.
Gu¨nther
R.
, “
Turbulence Properties of Flames and Their Measurement
,”
Prog. Energy Combust. Sci.
, Vol.
9
,
1983
, pp.
105
–
154
.
13.
Hoffmann, S., Habisreuther, P., Lenze, B., and Eickhoff, H., “Lean Stability Limits of Turbulent Swirling Natural Gas Flames,” Proc. International Gas Research Conference, Cannes, 1995, pp. 11–18.
14.
Hoffmann, S., and Lenze, B., “Das Stro¨mungs-und Reaktionsfeld sowie Stabilisierungseigenschaften in Drallflammen unter dem Einflußder inneren Ru¨ckstromzone,” DFG-Bericht AZ Le 399/7-1% 8-1, FIZ, Karlsuhe, 1996.
This content is only available via PDF.
Copyright © 1998
 by The American Society of Mechanical Engineers
You do not currently have access to this content.