Computational Investigation of Combustion Dynamics in a Lean-Direct Injection Gas Turbine Combustor
Technical paper Nov 2012-Jan 2013
AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIR
Pagination or Media Count:
Combustion dynamics is investigated using an integrated computationalexperimental approach for a laboratory-scale, single-element lean direct injection model combustor in which self-excited pressure oscillations are produced. The present study focuses on physics based computational simulations that fully describe the turbulence, spray, combustion and acoustics phenomena in the combustion chamber. Baseline three-dimensional results at an equivalence ratio 0.47 confirm the self-excitation of acoustic modes in the chamber and also indicate the presence of precessing vortex core instabilities. Preliminary comparisons of the pressure oscillations with experimental measurements are also presented. Further, the effects of multi-dimensionality, equivalence ratio and secondary atomization are computationally investigated. In contrast to the 3D simulations, two-dimensional models capture the pressure oscillations with reasonably similar amplitudes, but show inherent limitations in describing the vortex breakdown process. Pressure oscillations are also shown to be intensified when the equivalence ratio is increased and damped when the secondary atomization effects are included.
- Electricity and Magnetism
- Combustion and Ignition
- Jet and Gas Turbine Engines