Patent Application
20200224876
The present disclosure relates to injectors and atomizers, and more particularly to support structures of injectors and atomizers for gas turbine engines.
A variety of devices are known in the art for injection and atomization of liquids. One exemplary application for such devices is in fuel injection for gas turbine engines. Typical fuel injectors include an inlet fitting where fuel is introduced into the injector from a fuel line or manifold. Many fuel injectors include a feed arm structure extending from the inlet fitting to a nozzle body, where fuel is issued from the injector into a combustor, typically as an atomized spray.
Thermal management and weight saving are two major aspects of a turbine fuel nozzle design. Passing cold fuel through a channel impacted by hot combustion environment requires a certain amount of stretch in the fuel tubes to accommodate the thermal growth. Coiled tubes are often expensive and difficult to manufacture repeatedly as well as difficult to incorporate with dual passages. Known injector designs typically rely on some form of metallic conduit or tube to deliver fuel from a supply manifold to a nozzle body or atomizing tip. For strength, thermal management, and aerodynamic purposes, fuel tubes are typically brazed or welded to larger supporting structures such as a feed arm and inlet fitting. A wide variety of configurations are known, including injectors with multiple fuel circuits, multiple air blast circuits, heat shielding, and the like.
The conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for injectors and injector components having improved geometrical intricacy and reduced weight. There also remains a need in the art for such injectors and components that are economically viable. The present disclosure may provide a solution for at least one of these remaining challenges.
A fuel injector for a gas turbine engine includes a fuel inlet fitting for receiving fuel, with a feed arm mounted to the inlet. The feed arm having a lattice support structure. The lattice support structure is a continuous lattice of three-dimensional elements, a first conduit, and a second conduit in fluid communication with the inlet for conveying fuel from the inlet fitting through the feed arm, wherein the conduits are intertwined with each other. A nozzle body is operatively connected to the feed arm for injecting fuel from the conduits into a combustor of the gas turbine engine.
The three-dimensional elements of the lattice support structure can wrap around both of the conduits at multiple locations, and the conduits can be joined to the three-dimensional elements of the continuous lattice at multiple locations. Also, the lattice support structure can be mostly hollow. The conduits can form a double helix structure, for example angled at approximately a 45 degree angle with respect to the longitudinal axis.
The first conduit can have a larger diameter than the second conduit, and the three-dimensional elements of the continuous lattice can have a diameter smaller than the first conduit. The conduits can have wall thicknesses between 0.008 and 0.015 inches.
The conduits can be surrounded at least in part by an enclosure. The conduits can be joined to the enclosure at multiple locations, and the three-dimensional elements of the continuous lattice can also be joined to the enclosure at multiple locations. The conduits and enclosure can be surrounded at least in part by an exterior heat shield, which thermally insolates the conduits from external conditions. The enclosure can separated from the heat shield by a gap.
The lattice support structure can be configured to be a conduit for passing gaseous fuel from the inlet to the nozzle body. The conduits can merge into a single conduit at a first end or a second end. The feed arm can also include an integral mounting flange.
The lattice support structure can be of a material suitable for processing by at least one of: direct metal laser sintering, selective laser sintering, and electron beam melting. The feed arm can be can formed by an additive fabrication process.
These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
So that those skilled in the art to which the subject invention appertains will readily understand how to make and use the devices and methods of the subject invention without undue experimentation, preferred embodiments thereof will be described in detail herein below with reference to certain figures, wherein:
Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject invention. For purposes of explanation and illustration, and not limitation, a partial view of an exemplary embodiment of a fuel injector in accordance with the invention is shown in
Referring now to
As shown in
The three-dimensional elements 108 of the lattice support structure 106 wraps around both of the conduits 110, 112 at multiple locations, and the conduits 110, 112 are joined to the three-dimensional elements 108 of the continuous lattice 106 at multiple locations. The conduits 110, 112 form a double helix structure, for example angling at approximately a 45 degree angle with respect to the longitudinal axis, but can be adjusted based on thermal growth, strength, and envelope requirements. This angle could also be adjusted depending on the capability of the additive machine. The first conduit 110 is closer to the longitudinal axis, than the second conduit, wrapping around the longitudinal axis.
The first conduit 110 has a larger diameter (D1) than the diameter of (D2) second conduit 112, and the three-dimensional elements 108 of the continuous lattice 106 have a diameter (D3) smaller than the diameter (D1) of first conduit 110. The conduits 110, 112 have wall thicknesses between 0.008 to 0.015 inches. The first conduit 110 is to be made to accommodate a larger pressure than the second conduit 112. The first conduit 110 can be primary to the second conduit 112 for example for fuel staging. The conduits 110, 112 can have a cross-section that is a round shape, or can be “house shaped”, elliptical, diamond shaped, or any other suitable shape to aid in manufacturability. The three-dimensional elements 108 can have similar shapes and can have similar sizes to the conduits 110,112. The three-dimensional-elements 108 can be connected to each other and to the conduits 110,112 in various locations. The three-dimensional elements 108 can be woven using any necessary pattern or can be placed strategically to increase resistance.
The conduits 110, 112 are surrounded at least in part by an enclosure 116. The conduits 110, 112 are joined to the enclosure 116 at multiple locations, and the three-dimensional elements 108 of the continuous lattice 106 are also be joined to the enclosure 116 at multiple locations. The conduits 110, 112 and enclosure 116 are surrounded at least in part by an exterior heat shield 118, which thermally insolates the conduits 110, 112 from external conditions. The enclosure 116 is separated from the heat shield 118 by a gap 120, helping to further isolate the conduits 110, 112 and fuel from thermal stresses. The enclosure 116 and heat shield 118 is attached to each other at a single location 121 near the inlet fitting 102.
The lattice support structure 106 can also optionally provide a conduit 122 configured for passing gaseous fuel from the inlet 102 to the nozzle body 114. The conduit 122 can be the negative space through the three-dimensional elements 108 of the continuous lattice 106, the first 110, and second conduit 112. The conduits 110, 112 can optionally merge into a single conduit at a first end 124 or a second end 126, allowing fuel to enter the nozzle body 114 as one stream. It is also contemplated that the conduits 110, 112 can remain separate through the nozzle body 114 until sprayed into the combustor.
The lattice support structure 106 can be of a material suitable for processing by direct metal laser sintering, selective laser sintering, and electron beam melting, or any other suitable process or combination of processes. The lattice support structure 106 can also be made of Inconel™ 25 of Huntington Alloys Corporation of Huntington, W. Va. The feed arm 104 can be formed by an additive fabrication process.
These and other features of the systems and methods of the subject disclosure will become more readily apparent to those skilled in the art from the following detailed description of the preferred embodiments taken in conjunction with the drawings.
