Experimental investigation of combustion instabilities in lean swirl-stabilized partially-premixed flames in single- and multiple-burner setup

Abstract

In the present work, combustion instabilities of a modular combustor are investigated. The combustor operates with partially premixed, swirl-stabilized flames and can be operated in single-and different multiple-burner setups. The design parameters of the combustor prevent large-scale flame-flame interactions in the multiple-burner arrangements. The objective is to investigate how the interaction of the swirl jets affects the thermoacoustic stability of the combustor. Results of measurements of pressure oscillations and high-speed OH*-chemiluminescence imaging for the single-burner setup and two multiple-burner setups are discussed. Additionally, results of investigations with different flame characteristics are presented. These are achieved by varying the ratio of the mass flow rates through the swirlers of the doubleconcentric swirl nozzle. Several unstable modes with high pressure amplitudes are observed in the single-burner setup as well as in the multiple-burner setups. Numerical studies of the acoustic behavior of the combustor setups were performed that indicate that the different geometries show similar acoustic behaviors. The results lead to the conclusion that the interaction of the swirl jets in the multiple-burner setups affects the thermoacoustic response spectrum of the flame even in the absence of large-scale flame-flame interactions. Based on the findings in earlier studies, it is concluded that the differences in the flame response characteristics are induced by the reduction of the swirl intensity in the multiple-burner arrangements, which is caused by the exchange of momentum between the adjacent swirl jets.

Experimental analysis of thermo-acoustic instabilities in a generic gas turbine combustor by phase-correlated PIV, chemiluminescence, and laser Raman scattering measurements

“…However, a nearly identical setup is available for liquid fuels [Bärow 2013]. Further, the design allows for several identical burners to be combined into a combustor array, in order to investigate cross-flame interactions [Kraus 2013]. …”

Flame Extinction and Re-Ignition in a Swirl Stabilized Prevaporized Liquid Fuel Flame Close to Lean Blow-Out

“…A nearly identical setup is available for liquid fuels [24]. Further, the design allows for several identical burners to be combined into a combustor array, in order to investigate cross-flame interactions [25]. Previous studies have focused on the feedback mechanism of the thermo-acoustic cycle [21], the variations of the thermo-chemical state throughout the acoustic cycle [22], the influence of the air split ratio on the dynamics of a precessing vortex core (PVC) [23] and the impact of the material temperature on thermo-acoustic properties of the burner [26].…”

Coupling heat transfer and large eddy simulation for combustion instability prediction in a swirl burner

“…The KIT-Burner is described in detail in [40] and [41] , therefore only a brief presentation of its main features is given here.…”