Combustion instabilities in sudden expansion oxy–fuel flames

Ditaranto, Mario; Hals, Joergen

doi:10.1016/j.combustflame.2006.04.015

Cited by 113 publications

(78 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In this section we validate the non-linear quasi-1D code against experimental results from the oxy-fuel study of Ditaranto and Hals [20]. A schematic view of the geometry of the lab-scale combustion rig is shown in Figure 4.…”

Section: Sudden Expansion Burnermentioning

confidence: 94%

“…Thus, for the attached flame of Region 3 the 1/4 mode from the combustion chamber is at a signifi-cantly lower frequency (∼ 230 Hz) than the corresponding modes (∼ 300 Hz) for the cases in Region 2. According to Ditaranto and Hals [20], the instability Region 3 (Re=2000) Region 2 (Re=2000) Region 2 (Re=3000) Figure 6: The spectral distributions of pressure oscillations in the oxy-fuel rig as measured by Ditaranto and Hals [20]. The pressure spectra were recorded at microphone port 3 of the rig in two different instability regions.…”

Section: Oxy-fuel Combustionmentioning

confidence: 96%

“…In order to validate the non-reactive part of the non-linear code, acoustic simulations were performed for the geometry of the oxy-fuel rig described in [20], with no flame and only air present in the rig. Experimentally, in the cold rig case a loudspeaker was placed at the upstream end of the premixer, i.e., at the inlet at the left-end side of the set-up shown in Figure 4.…”

Section: The Cold Rigmentioning

confidence: 99%

“…In the oxy-fuel study of Ditaranto and Hals [20] four different combustion instability regimes, referred to as regions, were distinguished. In Figure 6 are shown typical spectral distributions obtained in the oxy-fuel experiment for two of these regions.…”

Section: Oxy-fuel Combustionmentioning

confidence: 99%

“…Boundary conditions is discussed in Section 3, while the new flame model is described in Section 4. Finally, the code is verified in Section 5 by comparing the simulation results with experimental results from a study of combustion instabilities in oxy-fuel flames by Ditaranto and Hals [20].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Nonlinear simulations of combustion instabilities with a quasi-1D Navier–Stokes code

Haugen

Langørgen

Sannan

2011

Journal of Sound and Vibration

View full text Add to dashboard Cite

As lean premixed combustion systems are more susceptible to combustion instabilities than non-premixed systems, there is an increasing demand for improved numerical design tools that can predict the occurrence of combustion instabilities with high accuracy. The inherent non-linearities in combustion instabilities can be of crucial importance, and we here propose an approach in which the one-dimensional Navier-Stokes and scalar transport equations are solved for geometries of variable cross-section. The focus is on attached flames, and for this purpose a new phenomenological model for the unsteady heat release from a flame front is introduced. In the attached flame method (AFM) the heat release occurs over the full length of the flame. The non-linear code with the use of the AFM approach is validated against results from an experimental study of thermoacoustic instabilities in oxy-fuel flames by Ditaranto and Hals [Combustion and Flame, 146, 493-512 (2006)]. The numerical simulations are in accordance with the experimental measurements and both the frequencies and the amplitudes of the resonant acoustic pressure modes are reproduced with good accuracy.

show abstract

Section: Sudden Expansion Burnermentioning

confidence: 94%

Section: Oxy-fuel Combustionmentioning

confidence: 96%

Section: The Cold Rigmentioning

confidence: 99%

Section: Oxy-fuel Combustionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Nonlinear simulations of combustion instabilities with a quasi-1D Navier–Stokes code

Haugen

Langørgen

Sannan

2011

Journal of Sound and Vibration

View full text Add to dashboard Cite

show abstract

Control of Acoustically Coupled Combustion Instabilities

Ducruix

Schuller

Durox

et al. 2010

Handbook of Combustion

View full text Add to dashboard Cite

This chapter reviews control methods for combustion instability. It specifically considers the rather general situation where instabilities are coupled by acoustic modes. The chapter begins with fundamental acoustic principles for reactive flows, leading to the acoustic energy balance equation. This equation is used to describe the three main control strategies that can be envisaged for combustion instabilities: (i) passive control methods (PCM); (ii) flame dynamic control methods (FDCM); (iii) active control methods (ACM). These schemes are considered successively. The survey begins with passive control methods (PCM) in which the dissipation of acoustic energy is augmented by ad hoc systems (acoustic liners, Helmholtz resonators, quarter wave cavities, and various other devices), which enhance absorption of acoustic energy. It is shown that such devices can be effectively used to modify the impedance of a boundary and that this can change the resonance properties of the combustor. Control of injection and flame dynamics is then envisaged. For this second group of methods (FDCM) it is shown that the flame geometry has a profound effect on the combustion response to incoming perturbations. The modification of the flow and flame configurations can thus be used to control the system response. It is then indicated that the dynamics of the injection system can be designed to decouple the system from the manifold feeding reactants into the combustor. Recent work indicates that the flame dynamics can be modified so that the combustion region becomes less susceptible to perturbations impinging on the flame. Finally, active control methods (ACM) are considered, and their application to combustion instability reduction is described. Implementation in the form of a closed loop control aims at modifying the feedback mechanism to hinder the resonant coupling between unsteady combustion dynamics and system acoustics. ACMs have been developed using various strategies, ranging from the control of injection parameters (fuel flow, air flow, secondary jets, etc.) to the active modulation of acoustic boundary conditions up‐ and downstream of the combustion chamber. Under application of the active control system, instabilities can be totally suppressed and the instability‐related flame extinctions are eliminated.

show abstract

Mitigating combustion instability and NO_x emissions with annular oxyfuel jets into the flame shear layer region

Tao

Zhou

2021

Asia-Pacific J Chem Eng

View full text Add to dashboard Cite

The shear layer is a region between the internal and external recirculating zone of the flame, which is critical for combustion stabilization and emission. This study experimentally studied the effects of oxyfuel (CO2/O2) shear layer injections on combustion dynamics and pollutant emissions of a model gas turbine combustor. To evaluate the damping performances of ‘Oxy’ CO2/O2 shear layer jets on unsteady combustion and pollutant formation processes, four variables of the CO2/O2 shear layer injection system are studied—the flow rate, the inner diameter, the injection angle and the oxygen ratio. Experimental results show that thermoacoustic instability and NOx emissions can be suppressed with the ‘Oxy’ CO2/O2 shear layer injection method. The minimum inner diameter cases could achieve better control effectiveness of 80%, with the sound pressure amplitude drops from 27 to 5.4 Pa. The maximum inner diameter case could achieve better control effectiveness of 59.2%, with the concentration of NOx emissions drops from 25 to 10.2 ppm. Flame oscillation modes experienced shifting and switching under different shear layer angles and oxygen ratios. There exist extreme points that can be selected for a better control effect. The CO2/O2 shear layer injection splits the inner and outer recirculation zones of the flame. As the oxygen ratio of CO2/O2 varied from 36% to 46%, a flame flapping phenomenon emerged. The ‘Oxy’ CO2/O2 shear layer injection method could eliminate combustion instability and NOx emissions at a relatively lower cost and complexity, which will promote the development of high‐performance burners.

show abstract

Combustion instabilities in sudden expansion oxy–fuel flames

Cited by 113 publications

References 32 publications

Nonlinear simulations of combustion instabilities with a quasi-1D Navier–Stokes code

Nonlinear simulations of combustion instabilities with a quasi-1D Navier–Stokes code

Control of Acoustically Coupled Combustion Instabilities

Mitigating combustion instability and NO_x emissions with annular oxyfuel jets into the flame shear layer region

Contact Info

Product

Resources

About

Combustion instabilities in sudden expansion oxy–fuel flames

Cited by 113 publications

References 32 publications

Nonlinear simulations of combustion instabilities with a quasi-1D Navier–Stokes code

Nonlinear simulations of combustion instabilities with a quasi-1D Navier–Stokes code

Control of Acoustically Coupled Combustion Instabilities

Mitigating combustion instability and NOx emissions with annular oxyfuel jets into the flame shear layer region

Contact Info

Product

Resources

About

Mitigating combustion instability and NO_x emissions with annular oxyfuel jets into the flame shear layer region