The visualization and mapping of turbulent premixed impinging flames

Abstract

Studies of the patterns and structures of turbulent premixed impinging flames and the regime of different flame modes are resolved. Up to four alternative combustion modes have been established under identical nozzle flow conditions. The creation of each alternative mode is dependent on the initial ignition location. Turbulence generation plays a very important role in wall stabilised flames. A high-speed digital camera and a high shutter speed colour video camera have been applied to visualize the observed combustion modes. A cellular structure can be induced by the use of a turbulence generator for fuel rich flames. However, this structure disappears if the jet is very fuel rich. The visualization also reveals that a ring flame is seldom a complete ring. The influence of plate temperature on the regimes of each mode has also been investigated. This has shown that water cooling of the flame impinged plate mainly modifies the flame characteristics of plate stabilised combustion modes. Its effect on other types of combustion is minimal. Nozzle turbulence characteristics have a very strong effect on the regimes of most of the combustion modes.