Experimental and LES Investigation of a SGT-800 Burner in a Combustion Rig

Abstract

The Siemens gas turbine SGT-800 has an annular combustor and 30 dry low emission burners. In order to further reduce the emission levels and to obtain improved understanding of the flow and associated flame dynamics, single burner rig tests have been performed. The laboratory measurements are complemented by Large Eddy Simulation (LES) to analyze the effect on the flame dynamics due to the transient fuel distribution and mixing process in the burner. The study includes both atmospheric and high pressure conditions. The computational model was developed jointly by Siemens Industrial Turbomachinery AB (SIT) and FOI. It is based on a finite rate chemistry LES model using a Partially Stirred Reactor (PaSR) turbulence chemistry interaction model and a two-step CH4/air mechanism developed by FOI. The results are compared to measurements performed jointly by SIT and Lund Institute of Technology. The experimental data includes wall temperature, pressure fluctuations, light intensity variation and simultaneous Planar Laser Induced Fluorescence of OH and acetone. The study is further complemented by Reynolds Averaged Navier-Stokes (RANS) calculations of the fuel concentration field evaluated to laser measurements in a water rig using the same burner configuration. Different burner fuel distributions are examined and the corresponding influence on the downstream mixing, fuel distribution and flame dynamics are studied. The results indicate that the fuel distribution upstream the flame, the detailed modeling of the fuel supply manifold, including the specification of numerical boundary conditions, and the flow in the fuel and air supply pipes, have significant influence on the flame dynamics. This is proven by the successful combustion LES of an unstable flame that experiences high flame dynamics and that a modification of the boundary conditions alters the dynamics resulting in a more stable flame. This is well in accordance with the experimental data and previous experience at SIT. The modal structures caused by the interaction between the flow, acoustics and flame dynamics are analyzed using the Proper Orthogonal Decomposition (POD) technique. The dominating modes in general originate from the burner mixing tube air-fuel-mass flow-interaction and flame-combustion chamber interaction.

Numerical Analysis of Turbulent Combustion in a Model Swirl Gas Turbine Combustor

“…This is caused by the highly nonisotropic turbulence structure, which is created by the high swirl levels applied to induce a flame-stabilizing vortex breakdown. In the previous work of present authors [5][6][7], it was shown that a three-dimensional and unsteady formulation that can resolve the unsteadiness of coherent structures is necessary for achieving sufficient accuracy in such flows (as also confirmed by the recent work of other authors [1][2][3][4]). This requirement is fulfilled (at different levels) by URANS and LES approaches.…”

“…Assuming and are independent, with the help of presumed PDFs, the average values of the thermochemical variables are obtained in a similar fashion to (2). In the present work, a single-delta PDF is assumed for (as it was commonly assumed in the previous applications of the model including the original work of Pierce and Moin [17]).…”

“…Fureby [1] applied an EDC-type combustion model in combination with LES to analyze GTC. Lörstad et al [2] analyzed the reacting flow in the Siemens SGT-800 burner experimentally and numerically applying RANS and LES approaches, along with an EDC-type combustion model, a focus of the work being on the effect of burner fuel distribution on flame dynamics. A recent study on URANS and LES modelling of GTC for a Siemens scaled combustor was presented by Goldin et al [3] using the flamelet generated manifold model as combustion model in combination with LES and turbulent flame speed models in combination with URANS.…”

Investigation of Hydrogen Enriched Natural Gas Flames in a SGT-700/800 Burner Using OH PLIF and Chemiluminescence Imaging

“…The central recirculation zone is a result of a vortex breakdown process and the outer recir culation zone is formed between the dump plane and the radially expanding flame tube. These occurrences have been predicted by both large eddy simulation calculations [20,21 ] and particle image velocimetry measurements performed in a water test rig using the same burner configuration. It is also seen that both of the flames are burning directly at the burner exit, they are thus mainly anch ored upstream the exit plane of the burner in the mixing tube.…”

“…In all experiments, the DLE burner was mounted in an atmos pheric combustion test rig that has also been used in previous stud ies [19][20][21]. The combustion chamber consists of a casing and a liner that is cooled convectively and has a single can configuration, see Fig.…”