This paper describes an experimental investigation into the interactions that occur between two acoustically forced lean turbulent premixed flames for an induced phase lag. Phase-averaged FSD from cinematographic OH-PLIF measurements and global heat release measurements were obtained for a range phase lags (Φ_S) and amplitudes (A) as a function of flame separation distance, 5. The effect of bringing two flames closer together causes jet merging, which alters the vortex flame interactions that drive the thermo-acoustic response. To simulate circumferential modes a phase lag was introduced, which affected the flame dynamics in the region of flame-flame interaction, with these changes dependent on S. For moderate separation distances, the flame structure becomes increasingly asymmetric inducing a very small transverse oscillation. However, for moderate phase lags (Φ_S≤ 20) the magnitude of these changes and their subsequent influence on the thermo-acoustic response was found to be slight in comparison with changes in S.
展开▼
