ABSTRACT
The great majority of gaseous fuels are easy to burn and control using simple techniques. Both the natural draught and air blast burners are pre-mixed systems with the air and gas mixed in varying degrees prior to the burner. If there is no prior mixing of the gas and air until the burner nozzle, the system is known as nozzle-mixing. Nozzle mix burners give improved mixing and slightly higher intensities than surface mix burners due to the gas and oxygen flows impinging just within the burner casing; the resulting turbulence produces poor flame definition with high noise levels. It is generally desirable to provide aeration control on industrial burners and this may be provided by an air shutter, by screwing up the injector orifice close to the mixture tube entry or by means of an adjustable disc in the burner throat. The burning velocity affects the design of aerated burners and introduces the problem of flame lift on post-aerated burners.
