PT Unknown
AU Witzel, B
TI Application of Optical Diagnostics to Support the Development of Industrial Gas Turbine Combustors
PD 11
PY 2016
LA en
AB The present study is concerned with the application of state-of-the-art optical measurement techniques for the detailed investigation of combustion systems of stationary gas turbines.
By using laser-induced fluorescence (LIF) with acetone as tracer imaging measurements of the fuel/air mixture at atmospheric pressure and at non-reacting conditions were accomplished with different burner types. For this purpose optically accessible test rigs as well as a special facility for the supply with necessary tracer mass flows were developed and taken into operation. The results of the tracer-LIF measurements were compared to results of classical suction-probe measurements. It could be shown that the tracer LIF measurements offer clear advantages regarding the spatial resolution as well as the necessary time for the execution of a measurement. Moreover, contrary to the suction-probe measurements, the tracer-LIF measurements for the first time allow the investigation of unsteady phenomena. Additionally, the recorded mixture data serve as a new reference for the validation of numerical simulations. A first comparison with steady RANS CFD results within the context of this study could already lead to optimized parameters for these simulations.
For the investigation of the flame behavior in high pressure combustion tests a water-cooled probe was developed which provides optical access to the combustion chamber with minimum impact on the examined system. The probe was applied for both spectroscopic as well as imaging measurements of the flame luminescence at gas turbine relevant thermodynamic boundary conditions. For the imaging measurements different combinations of optical filters were installed in front of the camera system in order to selectively record OH*, CH* or CO2*. Pressure fluctuations inside the combustion chamber were recorded simultaneously to the camera images. A correlation of the recorded images with the pressure fluctuations by using a phase-sorting algorithm gave new inside of the processes within the combustion chamber during the occurrence of combustion instabilities.
Altogether the optical measurement techniques applied in the frame of this study enabled new insights into the complex processes during fuel/air mixing as well as during combustion at gas turbine relevant boundary conditions. The new knowledge won thereby will make an important contribution for the further development of gas turbine combustion systems.
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