Combustion instabilities arise from interactions between the acoustic field and unsteady heat release within a confined chamber. In the present study, a three-dimensional acoustic model is developed to explore the effect of azimuthally nonuniform distribution of heat release on longitudinal combustion instabilities. The governing equations are solved by means of a spectral collocation method with domain decomposition to accommodate the flow discontinuities across the flame. Itis shown that the circumferential nonuniformityin heat release has only a marginal effect on instability frequency but may cause a potentially significant decrease in the growth rate. For some combinations of flow parameters, a high degree of heat-release asymmetry may qualitatively change the stability characteristics of the combustor, withasign change of the growth rate. It is found that vorticity waves produced by the azimuthally nonuniform heat release may contribute damping to the thermoacoustic system.
All Science Journal Classification (ASJC) codes
- Aerospace Engineering
- Fuel Technology
- Mechanical Engineering
- Space and Planetary Science