Environmental compatibility requires low-emission burners for gas turbine power plants as well as for jet engines. In the Past, significant progress has been made developing low NOx and CO burners. Unfortunately, these burners often have a more pronounced tendency than conventional burner designs to produce combustion driven oscillations. The oscillations may be excited to such an extent that pronounced pulsation may possibly occur; this is associated with a risk of engine failure. The stability of a burner system can be investigated by means of a stability analysis under the assumption of acoustical behavior. The problem with all these algorithms is the transfer function of the flame. A new method is presented here to predict the dynamic flame behavior by means of a full Navier-Stokes simulation of the complex combustion process. The first step is to get a steady-state solution of a flame configuration. After that a transient simulation follows with a sudden change in the mass flow rate at the flame inlet. The time-dependent answer of the flame to this disturbance is then transformed into the frequency space by a Laplace Transformation. This leads, in turn, to the frequency response representing the dynamic behavior of the flame. In principle, this method can be adapted for both diffusion as well as premixed flame systems. However, due to the fact that diffusion flames are more controlled by the mixing process than by the chemical kinetic, the method has first been used for the prediction of the dynamic behavior of turbulent diffusion flames. The combustion has been modelled by a mixed-is-burnt model. The influence of the turbulence has been taken into account by a modified k-ε model and the turbulence influences the combustion rate by presumed probability density functions (pdf). The steady state as well as the transient results have been compared with experimental data for two different diffusion flame configurations. Although the burner configuration is relatively complex, the steady-state results collaborate very well with the experiments for velocity, temperature, and species distribution. The most important result is that the heat release that drives the oscillations can be modeled sufficiently accurately. The effect of using different pdf models has been discussed and the best model has been used for the transient calculations of the dynamic flame behavior. The results for the frequency response of the flame are very encouraging. The principal behavior of the flame—higher order time element with a delay time—can be predicted with sufficient precision. In addition, the qualitative results collaborate fairly well with the experiments.

Issue Section:
Gas Turbines: Combustion and Fuels
Topics:
Flames, Turbulent diffusion, Combustion, Oscillations, Steady state, Transients (Dynamics), Diffusion flames, Frequency response, Stability, Turbulence, Acoustics, Algorithms, Delays, Density, Diffusion (Physics), Emissions, Engines, Failure, Flow (Dynamics), Gas turbines, Heat, Jet engines, Laplace transforms, Navier-Stokes equations, Nitrogen oxides, Power stations, Probability, Risk, Simulation, Temperature, Transfer functions
1.
Baade, P. K., 1974, “Selbsterregte Schwingungen in Gasbrennern,” Klima Ka¨lte Ingenieur.
2.
Bohn, D., and Deuker, E., 1993, “An Acoustical Model to Predict Combustion Driven Oscillations,” presented at the 20th International Congress on Combustion Engines (CIMAC), London.
3.
Deuker, E., 1995, “Ein Beitrag zur Vorausberechnung des akustischen Stabilita¨tsverhaltens von Gasturbinenbrennkammern mittels theoretischer und experimenteller Analyse von Brennkammerschwingungen,” Ph.D., thesis, RWTH Aachen, Germany.
4.
Lenz, W., 1980, “Die dynamischen Eigenschaften von Flammen und ihr Einfluß auf die Entstehung selbsterregter Brennkammer-schwingungen,” Ph.D. thesis, Uni Karlsruhe (T.H.), Germany.
5.
Lang, W., 1986, “Dynamik und Stabilita¨t selbsterregter Verbrennungsschwingungen beim Auftreten mehrerer Frequenzen. Ein erweitertes Stabilita¨tskriterium” Ph.D. thesis, TU Mu¨lnchen, Germany.
6.
Priesmeier, U., 1987, “Das dynamische Verhalten von Axialstrahl-Diffusionsflammen und dessen Bedeutung fu¨r selbsterregte Brennkammerschwingungen,” Ph.D. thesis, Uni Karlsryhe (T.H.), Germany.
7.
Merk, H. J., 1956, “An Analysis of Unstable Combustion of Premixed Gases,” presented at the Sixth Symposium (International) on Combustion.
8.
Becker, R., and Gu¨nther, R., 1973, “Niederfrequente nichtakustische Druckschwingungen in Brennkammern,” Chemie-Ing.-Techn.
9.
Bohn, D., and Kru¨ger., 1994, “Experimental and Theoretical Investigations on the Dynamic Behaviour of Flames Typical Used in Gas Turbine Combustors,” Numerical Modelling in Continuum Mechanics, Proceedings of the 2nd Summer Conference, Prague.
10.
Van Dormal
J. P.
, and
Raithby
G. D.
,
1984
, “
Enhancements of the SIMPLE Method for Predicting Incompressible Flows
,”
Numer. Heat Transfer
, Vol.
7
, pp.
147
–
163
.
11.
Rhie, C. M., 1981, “A numerical study of the flow past an isolated airfoil with separation,” Ph.D. thesis, University of Illinois at Urbana-Champaign, IL.
12.
Rhie
C. M.
, and
Chow
W. L.
,
1983
, “
Numerical Study of the Turbulent Flow Past an Airfoil With Trailing Edge Separation
,”
AIAA JI
, Vol.
21
, pp.
1527
–
1532
.
13.
Prade, B., 1993, “Experimentelle und theoretische Untersuchung zum Abblaseverhalten von turbulenten Stauscheibendiffusionsflammen,” Ph.D. thesis, Uni Karlsruhe (T.H.), Germany.
14.
Leuckel, W., “SFB 169—Hochbelastete Brennra¨um—stationa¨re Gleichdruckverbrennung,” Uni Karlsruhe (T.H.), Germany.
15.
Matsui
Y.
,
1981
, “
An Experimental Study on Pyro-Acoustic Amplification of Premixed Laminar Flames
,”
Combustion and Flame
, Vol.
43
, pp.
199
–
2009
.
16.
Sugimoto, T., and Matsui, Y., 1982, “An Experimental Study on the Dynamic Behavior of Premixed Laminar Flames,” presented at the Nineteenth Symposium (International) on Combustion/The Combustion Institute, pp. 245–250.
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