Fuel spray nozzle

Claim 2

A fuel spray nozzle comprising a main body having an inlet for receiving pressurized fuel and a discharge head formed with an orifice and adapted to discharge at least one generally hollow conical spray of fuel droplets at a predetermined spray angle into a gas turbine engine combustion apparatus, an annular, axially extending support surface formed on the outer periphery of said head adjacent its downstream end, an annular shield having an upstream end and a downstream end, said shield telescoped over said head and defining, in cooperation therewith, an annular, axially extending insulating airspace therebetween, with the upstream end of said shield connected to said head and the downstream end of said shield extending into close-fitting engagement with said head support surface to close said airspace at its downstream end and to permit unrestrained relative axial movement between said head and said shield, an annular shroud telescoped over said head and secured to said shield in radial spaced relationship thereto and defining, in cooperation with said shield and said head, an annular, generally axially extending air passage for directing fluid flow along the exposed outer surfaces of said shield and said head, said shroud includes a plurality of peripherally spaced, generally axially extending ribs projecting radially outwardly from the outer peripheral surface of said shroud, said ribs adapted to be slidingly received within an opening of said combustion apparatus and define, between said outer surface and said opening, a space for directing a film of fluid along said outer surface to prevent accumulation of deleterious matter thereon, said outer shroud surface being tapered to its downstream end.

Claim 3

The fuel spray nozzle of claim 1 further characterized in that said orifice terminates in a downstream opening, frustoconical guide surface having an apex angle approximately equal to said predetermined spray angle, said guide surface being of substantial axial length relative to the axial length of said orifice and extending to the downstream end of said discharge head, said discharge head formed with a divergently flared outer surface which defines, in cooperation with said guide surface, a sharp downstream edge for said discharge head, the inner surface of said shroud being flared at its downstream end so as to define, in cooperation with the flared outer surface of said discharge head, a divergent annular outlet for effluxing air from said air passage in close parallel proximity to the desired course of fuel droplets from said nozzle, the outer peripheral surface of said shroud converging to its downstream end so as to define, in cooperation with said flared inner surface, a generally downstream edge for said shroud.

Claim 4

The fuel spray nozzle of claim 2 further characterized in that the downstream end of said shroud and the downstream end of said head reside in closely spaced planes normal to said spray axis.

Claim 5

The fuel spray nozzle of claim 2 further characterized in that said convergent shroud surface is arcuate so as to establish a generally streamline flow of said fluid film therealong, the radial height of said ribs being substantially less than the radial depth of said shroud air passage, whereby said film merges with the conical flow from said divergent outlet without affecting the fuel spray angle.

Claim 6

In a gas turbine engine combustion apparatus of the type including a hollow body defining a combustion chamber therein, an upstream closure for said combustion chamber, and a fuel spray nozzle having a discharge head projecting into said combustion chamber through an opening in said upstream closure, said fuel spray nozzle including a main body having an inlet for receiving pressurized fuel, the improvement comprising: said discharge head formed with an orifice terminating in a downstream opening, frustoconical guide surface which extends to the downstream end of said discharge head for delivery of a generally hollow conical spray of fuel droplets into said combustion chamber, the outer peripheral surface of said discharge head being divergently flared to its downstream end, to define a sharp edge at the downstream end of the head and including an axially extending, annular guide surface, an annular shield having an upstream end fixedly connected to said discharge head, upstream of said combustion chamber, and a downstream end extending into close-fitting, sliding engagement with said guide surface, said shield defining an annular airspace intermediate its ends and about said discharge head, an annular shroud telescoped over said discharge head and said shield and defining an annular, generally axially extending air passage therebetween, said shroud having an upstream end fixedly connected upstream of said combustion chamber, to said shield, and a downstream end residing in a plane closely spaced downstream of said discharge head downstream end, said shroud including a plurality of peripherally spaced radial ribs slidably received in said closure opening and defining a small passage between the outer periphery of said shroud and said closure opening, with the inner surface of said shroud being divergently flared to its downstream end and the outer peripheral surface of said shroud being convergently tapered to its downstream end, whereby all surfaces of said fuel nozzle exposed to the combustion chamber are washed with either fuel or air without adverse effect to the fuel spray angle and low operating temperatures are maintained in said discharge head.

Claim 7

In a gas turbine engine combustion apparatus of the type including a hollow body defining a combustion chamber therein, an upstream closure for said combustion chamber, and a fuel spray nozzle having a discharge head projecting into said combustion chamber through an opening in said upstream closure, said fuel spray nozzle including a main body having an inlet for receiving pressurized fuel, the improvement comprising: said discharge head formed with an orifice terminating in a downstream opening, frustoconical guide surface which extends to the downstream end of said discharge head for delivery of a generally hollow conical spray of fuel droplets into said combustion chamber, the outer peripheral surface of said discharge head being divergently flared to its downstream end, to define a sharp edge at the downstream end of the head and including an axially extending, annular guide surface, an annular shield having an upstream end fixedly connected to said discharge head, upstream of said combustion chamber, and a downstream end extending into close-fitting, sliding engagement with said guide surface, said shield defining an annular airspace intermediate its ends and about said discharge head, an annular shroud telescoped over said discharge head and said shield and defining an annular, generally axially extending air passage therebetween, said shroud having an upstream end fixedly connected upstream of said combustion chamber, to said shield, and a downstream end residing in a plane closely spaced downstream of said discharge head downstream end, said shroud including a plurality of peripherally spaced radial ribs slidably received in said closure opening and defining a small passage between the outer periphery of said shroud and said closure opening, with the inner surface of said shroud being divergently flared to its downstream end and the outer peripheral surface of said shroud being convergently tapered to its downstream end, whereby all surfaces of said fuel nozzle exposed to the combustion chamber are washed with either fuel or air without adverse effect to the fuel spray angle and low operating temperatures are maintained in said discharge head.