Air blast fuel atomizer

Claim 1

A fuel nozzle for a gas turbine engine comprising a housing having passages therein adapted for communication with fuel and air pressure sources; primary and secondary atomizing means in said housing to supply combustible fuel-air mixtures to said engine; said primary atomizing means comprising a venturi tube having a throat in communication with said air and fuel passages whereby fuel introduced into said throat is atomized by the air flowing through said venturi tube with the fuel-air mixture being conducted to the engine from the downstream end of said venturi tube; said secondary atomizing means comprising a prefilming tube concentrically surrounding said venturi tube defining therewith and with said housing annular air passages which at their upstream ends are communicated with said air pressure source, said prefilming tube at its upstream end communicating with said fuel passage for flow of fuel in film form around the interior of said prefilming tube to the downstream end thereof from which it is discharged with a radially outward velocity component into the annular air stream around said prefilming tube; said annular air passages having swirl means associated therewith to impart swirling motion to the annular Air streams flowing therethrough; said housing having an additional passage with metering orifices upstream of the downstream end of said prefilming tube and downstream of the associated swirl means to introduce high velocity discrete jets of boost air, or oxygen, or gaseous fuel into and through the swirling annular air stream which surrounds said prefilming tube to impinge on the film of fuel as the latter emerges with a radial outward velocity component from the downstream end of said prefilming tube.