Fuel dispensing apparatus and method of operation
A fluid dispensing apparatus that may be additive manufactured as one unitary piece and may be a fuel injector for a gas turbine engine includes a radial displacement bellows having an outer surface that faces and may be exposed to a surrounding environment and an interior surface that faces and may define at least in-part a flowpath extending along a centerline. The radial displacement bellows is constructed and arranged to move between an expanded state when a pressure differential between the environment and the flowpath is low to a restricted state when the pressure differential is high.
1. A fuel injector for a gas turbine engine, the fuel injector extending axially along a centerline and comprising:
a radial displacement bellows having an outer surface facing a surrounding environment and an interior surface facing a flowpath extending along a centerline, wherein the radial displacement bellows is constructed and arranged to move radially relative to the centerline between an expanded state when a pressure differential between the environment and the flowpath is low to a restricted state that decreases a flow cross sectional area of the bellows when the pressure differential is high; and
a fuel spray nozzle axially engaged, relative to the centerline, to the radial displacement bellows and defining in-part the flowpath;
wherein the radial displacement bellows is configured to regulate a flow rate of fuel through the flowpath to the fuel spray nozzle by changing the cross sectional area of the bellows in response to variations of the pressure differential.
2. The fuel injector set forth in claim 1 , wherein the radial displacement bellows is made of a metal.
3. The fuel injector set forth in claim 2 , wherein the radial displacement bellows generally has a wall thickness of about 0.004 inches to 0.008 inches.
4. The fuel injector set forth in claim 1 , wherein the radial displacement bellows has a plurality of convolutions.
5. The fuel injector set forth in claim 1 , wherein the spray nozzle is fixed.
6. The fuel injector set forth in claim 1 , wherein the radial displacement bellows and the spray nozzle are additive manufactured as one unitary piece.
7. The fuel injector of claim 1 , wherein increasing the pressure differential moves the radial displacement bellows toward the restricted state and decreases a flow cross-sectional area of the flowpath within the radial displacement bellows.
8. The fuel injector of claim 1 , further comprising:
an axial displacement device defining in-part the flowpath;
wherein the axial displacement device is axially extended, relative to the centerline, when the radial displacement bellows is in the restricted state and retracted when the radial displacement bellows is in the expanded state.
9. The fuel injector of claim 8 , further comprising:
a rigid tube defining in-part the flowpath and located upstream of the radial displacement bellows and the axial displacement device;
wherein the fuel spray nozzle is located downstream of the radial displacement bellows and the axial displacement device; and
wherein the rigid tube and the spray nozzle are fixed.
10. The fuel injector of claim 8 , wherein the axial displacement device comprises a bellows.
11. The fuel injector of claim 1 , wherein at least the radial displacement bellows and the fuel spray nozzle are configured as a monolithic body.
12. The fuel injector of claim 1 , wherein a first portion of the flowpath extending along the centerline through the radial displacement bellows is angled relative to a second portion of the flowpath extending along the centerline through the fuel spray nozzle.
13. The fuel injector of claim 1 , wherein
a first portion of the centerline through the radial displacement bellows has a radial inward trajectory relative to an axis of the gas turbine engine; and
a second portion of the centerline through the fuel spray nozzle has an axial trajectory relative to the axis of the gas turbine engine.