The present disclosure relates to a fuel nozzle venturi in a rich-burn combustor for a gas turbine engine.
Some conventional gas turbine engines are known to include rich-burn combustors that typically use a swirler integrated with a fuel nozzle to deliver a swirled fuel/air mixture to a combustor. A radial-radial swirler is one example of such a swirler and includes both a primary radial swirler and a secondary radial swirler in tandem. A combustor with a radial-radial swirler also includes a venturi and a fuel nozzle that injects fuel into the venturi. The primary swirler is connected with the venturi to provide a flow of air to mix with the fuel injected into the venturi by the fuel nozzle so as to provide an air-borne fuel/air mixture within the opening of the venturi. The secondary swirler is connected to a flow passage outward of the venturi and provides a flow of air downstream of the venturi to mix with the fuel/air mixture exiting the venturi. In the conventional venturi, some of the fuel adheres to an inner surface of the venturi and flows to a downstream exit of the venturi. At the exit, the fuel on the surface of the venturi forms a thin liquid sheet that atomizes with the fuel/air mixture exiting the venturi, as well as mixes with the air flow from the secondary swirler.
According to one aspect, the present disclosure relates to a venturi for a swirler of a combustor for a gas turbine engine. According to this aspect, the venturi includes an annular wall extending in a longitudinal direction along a centerline axis from a forward end of the annular wall to an aft end of the annular wall, and extending radially outward from the centerline axis, the annular wall defining a fuel/oxidizer inlet at the forward end of the annular wall, and a fuel/oxidizer outlet at the aft end of the annular wall. The annular wall further includes an internal surface and an outer surface. An internal diameter of the forward end of the annular wall is larger than an internal diameter of a middle portion of the annular wall between the forward end of the annular wall and the aft end of the annular wall, and the internal diameter of the middle portion of the annular wall is smaller than an internal diameter of the aft end of the annular wall.
The venturi of this aspect of the disclosure further includes a forward wall extending radially outward with respect to the centerline axis, and a transition wall connecting the forward wall and the forward end of the annular wall. The transition wall has an internal surface extending from a forward surface of the forward wall to the internal surface of the annular wall. The internal surface of the annular wall includes a plurality of grooves in the internal surface of the annular wall, the plurality of grooves extending in the longitudinal direction along the internal surface of the annular wall, and each of the plurality of grooves having a groove forward end and a groove aft end.
According to another aspect, the present disclosure, relates to a fuel/oxidizer swirler for a combustor of a gas turbine engine. The fuel/oxidizer swirler of this aspect includes a forward oxidizer inlet swirler including a plurality of swirl vanes, the forward oxidizer inlet swirler including a fuel/oxidizer inlet arranged radially inward of the plurality of swirl vanes. The fuel/oxidizer inlet swirler of this aspect further includes a venturi disposed longitudinally aft of the forward oxidizer inlet swirler, and an aft oxidizer inlet swirler arranged radially outward of the venturi. The aft oxidizer inlet swirler includes a plurality of swirl vanes arranged radially outward of the venturi.
The venturi of this aspect includes an annular wall extending in a longitudinal direction along a centerline axis from a forward end of the annular wall to an aft end of the annular wall, and extending radially outward from the centerline axis, the annular wall defining a fuel/oxidizer inlet at the forward end of the annular wall, and a fuel/oxidizer outlet at the aft end of the annular wall. The annular wall includes an internal surface and an outer surface, where an internal diameter of the forward end of the annular wall is larger than an internal diameter of a middle portion of the annular wall between the forward end of the annular wall and the aft end of the annular wall. The internal diameter of the middle portion of the annular wall is smaller than an internal diameter of the aft end of the annular wall. The venturi further includes a forward wall extending radially outward with respect to the centerline axis and having a forward surface, where the forward wall defines an aft wall of the forward oxidizer inlet swirler.
The venturi of this aspect further includes a transition wall connecting the forward wall and the forward end of the annular wall, where the transition wall has an internal surface extending from the forward surface of the forward wall to the internal surface of the annular wall. The internal surface of the annular wall includes a plurality of grooves in the internal surface of the annular wall, the plurality of grooves extending in the longitudinal direction along the internal surface of the annular wall, and each of the plurality of grooves having a groove forward end and a groove aft end.
Additional features, advantages, and embodiments of the present disclosure are set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the disclosure as claimed.
The foregoing and other features and advantages will be apparent from the following, more particular, description of various exemplary embodiments, as illustrated in the accompanying drawings, wherein like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.
Various embodiments are discussed in detail below. While specific embodiments are discussed, this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without departing from the spirit and scope of the present disclosure.
As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components.
The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.
As was briefly discussed above, in conventional rich-burn combustors having a radial-radial swirler and a venturi, some of the fuel adheres to an inner surface of the venturi and flows to a downstream exit of the venturi. At the exit, the fuel on the surface of the venturi forms a thin liquid sheet that atomizes with the fuel/air mixture exiting the venturi, as well as mixing with the air flow from the secondary swirler. For this type of architecture, the flow usually has high-frequency spectral components that can couple with transverse modes of the combustion chamber, and also low-frequency spectral content that are usually axial in nature. Both types of flow spectral components are usually driven by the location of fuel within the swirler's venturi. In general, the lower the air-borne fuel within the venturi, the lower the flow's high-frequency spectral levels. However, the flow's low-frequency spectral levels increase with lower air-borne fuel within the venturi (i.e., in an opposite manner). This indicates that the flow's low-frequency spectral content is largely driven by coherent atomization of the liquid fuel from the exit of the swirler's venturi.
The present disclosure aims to address the foregoing by affecting the coherent liquid sheet breakup/atomization at the venturi exit. In the present disclosure, a venturi for a swirler of a combustor for a gas turbine engine includes rifling-type grooves about the inner circumferential surface of the venturi. The specific arrangement of the rifling-type grooves can be determined based on the dynamics affects to be achieved. For example, the width of the grooves may vary from application to application (i.e., different types of combustors), or may vary from the forward end (inlet) of the venturi to the aft end (exit) of the venturi, or may vary circumferentially. The depth of the grooves may also vary from application to application, or may vary from the forward end to the aft end of the venturi, or may vary circumferentially. The grooves may also be angled with respect to a centerline axis of the venturi, or may be spiraled about the circumference. The beginning point and ending point of the grooves along the length of the venturi may also vary depending on the particular application, or a desired dynamics effect to be achieved. The spacing between the grooves can also vary. One object of the rifling-type grooves is to break up the otherwise coherent thin liquid sheet exiting the venturi, which reduces the flow's low-frequency spectral content. The grooves also help to reduce the air-borne fuel/air content so as to help reduce the flow's high-frequency spectral content. The present disclosure can further help to reduce the flow's low-frequency spectral content that may arise from swirler changes that are designed to lower the flow's high-frequency spectral content.
Referring now to the drawings,
The core engine 16 may generally include an outer casing 18 that defines an annular inlet 20. The outer casing 18 encases or at least partially forms, in serial flow relationship, a compressor section having a booster or low pressure (LP) compressor 22, a high pressure (HP) compressor 24, a combustion section 26, a turbine section including a high pressure (HP) turbine 28, a low pressure (LP) turbine 30, and a jet exhaust nozzle section 32. A high pressure (HP) rotor shaft 34 drivingly connects the HP turbine 28 to the HP compressor 24. A low pressure (LP) rotor shaft 36 drivingly connects the LP turbine 30 to the LP compressor 22. The LP rotor shaft 36 may also be connected to a fan shaft 38 of the fan assembly 14. In particular embodiments, as shown in
As shown in
The secondary swirler 72 (i.e., an aft oxidizer inlet swirler) similarly includes swirl vanes 84 that are circumferentially disposed in a row such that each of the swirl vanes 84 extends radially inward to a vane lip 88. Thus, the secondary swirl of 72 is configured for swirling another corresponding portion of the pressurized air 82(a) from the pressure plenum 66 radially inward from the plurality of swirl vanes 84 of secondary swirler 72.
The fuel nozzle assembly 52 is seen to include a fuel nozzle 90 disposed within a forward portion of the swirler assembly 50. The fuel nozzle 90 ejects a fuel 92 into the venturi 100 where it is mixed with the air 82(a) from primary swirler 70. The fuel air mixture in the venturi further mixes downstream with the air 82(a) from secondary swirler 72 downstream of the venturi 100. The venturi 100 radially separates the air swirled from the swirl vanes 74 and the swirl vanes 84. As will be described in more detail below, an inner flow surface of the venturi 100 converges to a throat of minimum flow area and then diverges to the outlet end thereof for discharging the fuel and air mixture from the swirler.
In
Referring back to
In
In one aspect, the grooves 126 are angled or spiraled in the same direction as that of the primary swirl of the air from primary swirler 70. However, it can be understood that the grooves 126 may be arranged at an angle different from that of the primary swirl, such that the primary swirl of the primary swirler 70 is at least somewhat across the grooves 126.
In
Referring again to
As seen in
As was discussed above, the rifling-type grooves breakup the otherwise coherent thin liquid sheet exiting the venturi, which can reduce the flow's low-frequency spectral content. The grooves also help to reduce the air-borne fuel/air content so as to help reduce the flow's high-frequency spectral content. The present disclosure can further help to reduce low-frequency effects that may arise from swirler changes that are designed to lower flow's high-frequency effects.
While the foregoing description relates generally to a gas turbine engine, it can readily be understood that the gas turbine engine may be implemented in various environments. For example, the engine may be implemented in an aircraft, but may also be implemented in non-aircraft applications such as power generating stations, marine applications, or oil and gas production applications. Thus, the present disclosure is not limited to use in aircraft.
Further aspects of the present disclosure are provided by the subject matter of the following clauses.
A venturi for a swirler of a combustor for a gas turbine engine, the venturi comprising, an annular wall extending in a longitudinal direction along a centerline axis from a forward end of the annular wall to an aft end of the annular wall, and extending radially outward from the centerline axis, the annular wall defining a fuel/oxidizer inlet at the forward end of the annular wall, and a fuel/oxidizer outlet at the aft end of the annular wall, wherein the annular wall includes an internal surface and an outer surface, and wherein an internal diameter of the forward end of the annular wall is larger than an internal diameter of a middle portion of the annular wall between the forward end of the annular wall and the aft end of the annular wall, and wherein the internal diameter of the middle portion of the annular wall is smaller than an internal diameter of the aft end of the annular wall, a forward wall extending radially outward with respect to the centerline axis, and a transition wall connecting the forward wall and the forward end of the annular wall, the transition wall having an internal surface extending from a forward surface of the forward wall to the internal surface of the annular wall, wherein the internal surface of the annular wall comprises a plurality of grooves in the internal surface of the annular wall, the plurality of grooves extending in the longitudinal direction along the internal surface of the annular wall, and each of the plurality of grooves having a groove forward end and a groove aft end.
The venturi according to any preceding clause, wherein the plurality of grooves are circumferentially spaced equidistant from one another about the internal surface of the annular wall.
The venturi according to any preceding clause, wherein the plurality of grooves extend, in the longitudinal direction, from the forward end of the annular wall to the aft end of the annular wall.
The venturi according to any preceding clause, wherein the plurality of grooves extend, in the longitudinal direction, from the middle portion of the annular wall to the aft end of the annular wall.
The venturi according to any preceding clause, wherein the plurality of grooves extend, in the longitudinal direction, from a middle portion of the transition wall to the aft end of the annular wall.
The venturi according to any preceding clause, wherein each of the plurality of grooves has a depth (D), and wherein the depth (D) of each of the plurality of grooves is greater at the groove forward end than at the groove aft end.
The venturi according to any preceding clause, wherein an angle of each of the plurality of grooves in the longitudinal direction in relation to the centerline axis has a range from zero to forty-five degrees.
The venturi according to any preceding clause, wherein each of the plurality of grooves has a groove width (GW), and the depth (D) of each of the plurality of grooves has a range from 25% to 75% of the groove width (GW).
The venturi according to any preceding clause, wherein each of the plurality of grooves has a groove width (GW), wherein a portion of the internal surface of the annular wall between each of the plurality of grooves defines a land, and wherein a land width (LW) of the land has a range from 50% to 150% of the groove width (GW).
The venturi according to any preceding clause, wherein, in a cross-sectional view orthogonal to the centerline axis through the annular wall, the plurality of grooves define a sine wave structure.
The venturi according to any preceding clause, wherein the sine wave structure is a trapezoidal sine wave structure.
A swirler assembly for a combustor of a gas turbine engine, the swirler assembly comprising, a primary swirler including a plurality of swirl vanes, the primary swirler including a fuel/oxidizer inlet arranged radially inward of the plurality of swirl vanes, a venturi disposed longitudinally aft of the primary swirler; and a secondary swirler arranged radially outward of the venturi, the secondary swirler including a plurality of swirl vanes arranged radially outward of the venturi, wherein the venturi comprises, an annular wall extending in a longitudinal direction along a centerline axis from a forward end of the annular wall to an aft end of the annular wall, and extending radially outward from the centerline axis, the annular wall defining a fuel/oxidizer inlet at the forward end of the annular wall, and a fuel/oxidizer outlet at the aft end of the annular wall, wherein the annular wall includes an internal surface and an outer surface, an internal diameter of the forward end of the annular wall is larger than an internal diameter of a middle portion of the annular wall between the forward end of the annular wall and the aft end of the annular wall, and the internal diameter of the middle portion of the annular wall is smaller than an internal diameter of the aft end of the annular wall, a forward wall extending radially outward with respect to the centerline axis and having a forward surface, the forward wall defining an aft wall of the primary swirler, and a transition wall connecting the forward wall and the forward end of the annular wall, a forward end of the transition wall defining a fuel/oxidizer inlet, an internal diameter of the forward end of the transition wall being greater than the internal diameter of the forward end of the annular wall, and a diameter of an aft end of the transition wall being equal to the internal diameter of the forward end of the annular wall, the transition wall having an internal surface extending from the forward surface of the forward wall to the internal surface of the annular wall, wherein the internal surface of the annular wall comprises a plurality of grooves in the internal surface of the annular wall, the plurality of grooves extending in the longitudinal direction along the internal surface of the annular wall, and each of the plurality of grooves having a groove forward end and a groove aft end.
The swirler assembly according to any preceding clause, wherein the plurality of grooves are circumferentially spaced equidistant from one another about the internal surface of the annular wall.
The swirler assembly according to any preceding clause, wherein the plurality of grooves extend, in the longitudinal direction, from the forward end of the annular wall to the aft end of the annular wall.
The swirler assembly according to any preceding clause, wherein the plurality of grooves extend, in the longitudinal direction, from the middle portion of the annular wall to the aft end of the annular wall.
The swirler assembly according to any preceding clause, wherein the plurality of grooves extend, in the longitudinal direction, from a middle portion of the transition wall to the aft end of the annular wall.
The swirler assembly according to any preceding clause, wherein each of the plurality of grooves has a depth (D), and wherein the depth (D) of each of the plurality of grooves is greater at the groove forward end than at the groove aft end.
The swirler assembly according to any preceding clause, wherein an angle of each of the plurality of grooves in the longitudinal direction in relation to the centerline axis has a range from zero to forty-five degrees.
The swirler assembly according to any preceding clause, wherein each of the plurality of grooves has a groove width (GW), and the depth (D) of each of the plurality of grooves has a range from 25% to 75% of the groove width (GW).
The swirler assembly according to any preceding clause, wherein each of the plurality of grooves has a groove width (GW), wherein a portion of the internal surface of the annular wall between each of the plurality of grooves defines a land, and wherein a land width (LW) of the land has a range from 50% to 150% of the groove width (GW).
Although the foregoing description is directed to some exemplary embodiments of the present disclosure, it is noted that other variations and modifications will be apparent to those skilled in the art, and may be made without departing from the spirit or scope of the disclosure. Moreover, features described in connection with one embodiment of the present disclosure may be used in conjunction with other embodiments, even if not explicitly stated above.
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