Abstract
Lean premixed combustion is one of the most efficient techniques to reduce nitrogen oxide (NO_x) emission. However, lean premixed combustors have narrow stable combustion range compared with diffusion combustors and have a risk of flashback. In this study, we present characteristics of flame propagation in a premixed burner with swirling flow in order to investigate unsteady flame behavior in the premixer. Two kinds of mixture gas supply techniques were used in order to investigate the characteristics of flame propagation. One is a normal swirler closed a center valve and the other one opened it. The flame with the closed center swirler is prone to flash back rather than that with the open one. The characteristics of flame propagation interacting with flow fields in a premixer have been investigated by applying high-speed particle image velocimetry (PIV) measurement.
