In this work we experimentally investigated the effect of a slit at the vertex of a V-gutter on combustion instability in the turbulent wake flame. Influences of blow-off mechanisms near both lean and rich limits on the combustion-induced oscillation were also studied. Results showed that a proper slit of the V-gutter could suppress the combustion instability and the flame quenching at low frequency. However, oscillations at higher frequencies might become main sources of combustion instability if the opening was overextended. In the fuel-lean condition, the diverted-jet flame was a stabler heat source and the main instability came from fluctuations of the reacting shear layer. The instability mode was similar to that of a regular V-gutter under the same operating conditions. Near the rich limit, however, it was more difficult for the jet flame to exist in the wake, while the flame was always re-ignited from the shear layer opposite to the jet flow due to a stronger mixing mechanism. Thus, strong oscillations were induced by the unstable heat release both in fuel-lean and fuel-rich conditions with distinct mechanisms.
中國機械工程學刊=Journal of the Chinese Society of Mechanical Engineers 20(1)，頁59-65