The goals of the
proposed project are a detailed experimental characterization of non-stationary
combustion processes in gas turbine relevant flames with the focus on periodic
combustion instabilities and the establishment of a data archive which is suited
for the further development and verification of numerical flame simulations.
The measurements will be performed in the CRC 606 standard combustor (gas film
nozzle) for swirled, (partially) premixed flames. Within this project, the use
of gaseous fuels at atmospheric pressure is planned. A combustion chamber with
good optical access will enable the application of optical and laser diagnostic
measuring techniques.
Methods to be
applied are chemiluminescence imaging, planar laser induced fluorescence of OH
and laser Raman scattering. Further, innovative high-speed laser diagnostics
with pulse repetition rates beyond 1 kHz will be applied to temporally resolve
non-stationary processes in the flames. For oscillating flames, the acoustic
pressure fluctuations are monitored and the measuring techniques are applied in
phase-correlation to the oscillations. Unsteady combustion phenomena like
thermoacoustic pulsations, hydrodynamic instabilities or, in general, the
flame-vortex interactions will be studied in order to better understand the
underlying mechanisms.
A further aspect
of the investigations are finite-rate chemistry effects and their influence on
flame stabilization. For well-defined “standard flames”, detailed experimental
data sets will be established including flow velocities, temperature, major
species concentrations, mixture fraction, OH and OH* distributions and acoustic
frequency spectra. Theses data sets serve for the validation and improvement of
theoretical models and numerical flame simulations.
