The present disclosure relates to gas turbine engines and, more particularly, to cooling arrangements suitable for torch igniters used in the combustor section of a gas turbine engine.
Torch igniters can be used in lieu of spark igniters to provide an ignition source for combustors located in gas turbine engines. Torch igniters provide a flame as an ignition source for a combustor rather than the electric current provided by spark igniters. Consequently, torch igniters can provide a larger target for fuel injectors used in a combustor, permitting the use of a greater range of fuel injector designs. However, due to their location in a gas turbine engine, torch igniters can experience temperatures exceeding 3000-4000° F. These high temperature conditions can exceed the thermal limits of materials used in torch igniter construction, negatively impacting the durability of the torch igniter device.
In one embodiment, the present disclosure provides a torch igniter for a combustor of a gas turbine engine comprises a combustion chamber oriented about an axis, a cap defining an axially upstream end of the combustion chamber and oriented about the axis, a tip defining an axially downstream end of the combustion chamber, a structural wall coaxial with and surrounding the igniter wall, an outlet passage defined by the igniter wall within the tip, and a cooling system. The upstream and downstream ends define a flow direction through the combustion chamber, the cap is configured to receive a fuel injector and a glow plug, and the outlet passage is fluidly connected to the combustion chamber. The cooling system comprises an air inlet formed within the structural wall, a first flow path disposed between the structural wall and the igniter wall, and an aperture extending through the igniter wall transverse to the flow direction. The air inlet is configured to intake a flow of air from a compressor section of the gas turbine engine, the first flow path extends from the inlet to the cap and is configured to receive a first portion of the air taken in by the inlet, and the aperture fluidly connects the second flow path to the combustion chamber.
In another embodiment, the present disclosure provides a method of cooling a torch igniter in a gas turbine engine that includes intaking a flow of air, flowing a first portion of the flow through a first flow path, and flowing the first portion of the air through an aperture. The air is taken in at an air inlet formed in a structural wall of an igniter. The structural wall extends coaxially with and surrounds an igniter wall. The igniter wall defines a combustion chamber within the torch igniter. The first flow path is disposed between the structural wall and the igniter wall and extends from the inlet toward a cap defining an upstream end of the torch igniter. The aperture directly fluidly connects the first flow path to the combustion chamber.
While the above-identified figures set forth one or more embodiments of the present disclosure, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings.
The present invention includes structures and methods for cooling torch igniters within the combustor section of a gas turbine engine. These structures and methods cool a torch igniter with high-pressure air, such as air exiting the high-pressure section of a gas turbine engine. This air is subsequently fed into a combustion chamber of the torch igniter for combustion within the torch igniter, preventing potential downstream thermal stress that could result from allowing the cooling air to bypass the combustor section. The cooling schemes of the present invention allow a torch igniter to be constructed from high-temperature metallic components and can be produced via additive manufacturing.
In the illustrated embodiment, torch igniter 10 is arranged such that tip section 30, combustion section 32, and cap section 34 are all oriented about axis A-A. Arrow 42 shows the general direction of flow for fluids from combustion chamber 16 through outlet passage 40. Thus, torch igniter 10 has upstream and downstream ends oriented along axis A-A and according to the direction of arrow 42. Combustion chamber 16 and outlet passage 40 are fluidly connected such that gases are able to flow from combustion chamber 16 toward tip section 30 and to outlet passage 40. Gases are able to exit torch igniter 10 and enter an internal volume of the combustor via outlet passage 40. To this extent, cap section 34 is disposed at the upstream end of torch igniter 10 and tip section 30 is disposed at the downstream end of torch igniter 10. It should be understood, however, that tip section 30 may be disposed at any suitable location on the downstream end of torch igniter 10, and oriented in any direction suitable to direct flame for engine ignition, including locations/orientations not coaxial with axis A-A.
During operation, combustion occurs within combustion chamber 16. Hot gases exit torch igniter 10 into a combustor of a gas turbine engine via outlet passage 40. Generally, the portion of torch igniter 10 internal to structural wall 36 is at a higher pressure than the area external to structural wall 36 during operation. Structural wall 36 functions as a pressure vessel and is generally strong enough that it does not deform or leak gases, such as combustion gases or cooling air, under this operational pressure differential. However, the rigidity of structural wall 36 can be negatively affected by the high temperatures of combustion gases produced in combustion chamber 16. Igniter wall 38 acts as a liner to protect the material integrity of structural wall 36 from the heat of combustion in combustion chamber 16. Advantageously, cooling of igniter wall 38 via air circulating through channel 28 allows torch igniter 10 to be constructed monolithically from a metallic material, including metallic materials readily fabricable via additive manufacturing. Likewise, additive manufacturing techniques enable the construction of complex cooling structures within channel 28, such as cooling fins, to improve cooling of igniter wall 38.
Torch igniter 10 causes combustion within combustion chamber 16 by using injector 44 to inject a fuel-air mixture onto the surface of glow plug 26. Glow plug 26 extends through cap section 34, such that it has an internal end and an external end. Further, glow plug 26 can be resistively heated such that it is able to ignite the fuel-air mixture injected by injector 44. Injector 44 generally injects the fuel-air mixture in a conical volume centered on axis A that impinges on the internal end of glow plug 26. To improve ignition of fuel injected by fuel injector 44, torch igniter 10 can be configured with multiple glow plugs 26 at multiple locations within combustion chamber 16. Further, if the injection pattern of injector 44 is distorted by coking, for example, using multiple glow plugs 26 at multiple locations within combustion chamber 16 can improve the likelihood that the injected fuel impinges on at least one glow plug 26. For example, torch igniter 10 can in some embodiments be equipped with six glow plugs 26 distributed circumferentially, and in some cases symmetrically, about cap section 34.
Generally, glow plug 26 is mounted to cap section 34 via glow plug housing 46. Glow plug housing 46 extends through structural wall 36 and igniter wall 38 of torch igniter 10 and thereby allows glow plug 26 to extend into combustion chamber 16. Glow plug 26 may be removably attached to glow plug housing 46, such as by a screw attachment, or may be non-removably attached to glow plug housing 46. In some examples where glow plug 26 is removably attached, it is brazed to a metal sheath. The sheath can have, for example, screw-threading that allows glow plug 26 to be attached via screw attachment.
Glow plug 26 is also connected to a power source capable of delivering electric current to the external end of glow plug 26, allowing for the electrically-resistive heating of glow plug 26. In examples where torch igniter 10 contains multiple glow plugs 26, they may be connected to more than one power source or may be connected in a series, parallel, or combination arrangement to a single power source. Generally, glow plug 26 is formed of a material capable of being non-destructively resistively heated. For example, glow plug 26 can be formed of a ceramic material such as silicon nitride.
Injector 44 is fed the fuel-air mixture from air source 48 and fuel source 50. Air from air source 48 and fuel from fuel source 50 travel according to arrows 52 toward the nozzle of injector 44. An annulus near the nozzle of injector 44 allows for the controlled mixing of air and fuel. This configuration allows injector 44 both to meter fuel usage and to atomize the fuel that is injected by injector 44. Injector 44 is shown as removably connected via screw threads, but it should be understood that any appropriate connector may be used to removably connect injector 44 and further that injector 44 may be irremovably connected to torch igniter 10. Where injector 44 is removably connected, it may be inserted through an aperture in cap section 34.
Arrows 60 indicate the general flow path of cooling air through cooling channel 28. Torch igniter 10 intakes high-pressure air from inside high-pressure case 18 via inlet 62. As shown by arrows 60, the air entering air inlet 62 first flows radially inward toward igniter wall 38. The air then splits into two main flow paths. One flow path flows air toward the end of tip section 30 and through outlet 64, providing cooling air to the entirety of igniter wall 38 within tip section 30. Outlet 64 is fluidly connected to combustor 24 and provides air flowing toward combustor liner 22 in tip section 30 to the interior of combustor 24. The other flow path flows air toward cap section 34 and elbow region 66.
Elbow region 66 is formed by the difference in the diameter of igniter wall 38 where it surrounds combustion chamber 16 and outlet passage 40. In the depicted example, igniter wall 38 turns approximately 90° at elbow region 66. Consequently, channel 28 extends generally radially through elbow region 66. However, it should be understood that igniter wall 38 can bend at any angle suitable to constrain or direct hot combustion gases flowing through combustion chamber 16 towards outlet passage 64, including non-90° angles.
Metering hole 68 is disposed downstream of the internal ends of glow plugs 26 in elbow region 66 and functions to reduce or meter the flow of air flowing through channel 28 to air swirl hole 70 and thereby optimize ignition conditions near fuel injector 44. Air leaving metering hole 68 also functions to facilitate the combustion of any residual fuel leaving combustion chamber 16 and entering outlet passage 40, preventing introduction of unignited fuel in combustor 24. Generally, combustion gases flowing through combustion chamber 16 tend to be hotter at elbow region 66 than in other locations throughout the torch igniter. Further, the narrowing of igniter wall 38 at elbow region 66 causes acceleration of combustion gases through outlet passage 40, resulting in creased convection of hot combustion gases near elbow region 66. This causes greater heat transfer into igniter wall 38 at elbow region 66 than other regions of igniter wall 38. When metering hole 68 is disposed adjacent to the portion of igniter wall 38 in elbow region 66, the air diverted through metering hole 68 can cool gases at elbow region 66 to protect igniter wall 38, thereby increasing the longevity of igniter wall 38.
The portion of air that is not diverted through metering hole 68 continues flowing to the section of channel 28 embedded in cap section 34 and further to air swirl hole 70. Air swirl hole 70 is disposed at an upstream location of torch igniter 10 and fluidly connects channel 28 to combustion chamber 16. In the depicted example, channel 28 turns back approximately 180° and forms a dual-layer structure in cap section 34 with the outer layer connected to air swirl hole 70, which allows channel 28 to cool the entirety of igniter wall 38 along the inside of cap section 34 while also allowing for air swirl hole 70 to be positioned along igniter wall 38 at a location outside of cap section 34 and to be oriented transversely to flow direction 42 or the inner portion of channel 28. To connect channel 28 to combustion chamber 16 from the exterior portion of cap section 34, air swirl hole 70 extends through and crosses the inner portion of channel 28. Generally, the crossing portion of channel 28 is not fluidly connected to the inner portion of channel 28. Air entering combustion chamber 16 through air swirl hole 70 is used with the air-fuel mixture injected by injector 44 for combustion within combustion chamber 16. In the depicted example, air swirl hole 70 is positioned upstream of the interior end of glow plug 26 to optimize mixing of air entering through air swirl hole 70 with combustion gases inside combustion chamber 16. Air exiting air swirl hole 70 can also be used to prevent buildup of fuel along igniter wall 38 and further to create recirculation zones within combustion chamber 16 suitable for maintaining a self-sustaining flame. It should be understood, however, that air swirl hole 70 may be positioned at any suitable location along combustion chamber 16.
Thus, the configuration of cooling channel 28 shown in
In the depicted embodiment, air swirl hole 70 is positioned upstream of the interior end of glow plugs 26. The depicted position and previously described transverse orientation of air swirl hole 70 allows air exiting air swirl hole 70 to create a recirculation zone within combustion chamber 16. More specifically, the transverse entry of air into combustion chamber 16 creates a low-pressure zone along the centerline of axis A-A and allows for upstream flow of combustion gases along the perimeter of combustion chamber 16. Upstream-flowing combustion gases are heated from the combustion reaction, allowing them to evaporate fuel injected by fuel injector 44 and thereby perpetuate combustion. This allows torch igniter 10 to operate with a self-sustaining flame that does not require continuous resistive heating of glow plugs 26. Rather, in examples where torch igniter 10 can create a self-sustaining flame, glow plugs 26 can be resistively heated only to create an initial ignition of fuel within combustion chamber 16 and then their resistive heating can be stopped. Glow plugs 26 can then remain inactive during continuous operation, with additional air supplied by air swirl hole 70 and fuel supplied by injector 44 perpetuating combustion inside combustion chamber 16.
Generally, torch igniter 10 operates continuously during the entire operation time of the gas turbine engine in which it is located. Continuous operation allows torch igniter 10 to easily facilitate altitude re-lights of combustor 24 by acting as a pilot light for fuel ignition within combustor 24. Though torch igniter 10 generally operates continuously, torch igniter 10 may experience an unexpected blow-out at high altitudes. While torch igniter 10 is not operating, it is not able to relight combustor 24 in the event of a subsequent or simultaneous blow-out of combustor 24. Advantageously, combustion chamber 16 is sufficiently large that combustion can occur within combustion chamber 16 when air entering high-pressure case 18 from inlet 17 is at a relatively low-pressure, such as at high altitudes while combustor 24 is not lit. Thus, even at high altitudes, torch igniter 10 can be re-lit and thereby re-light combustor 24 after blow-outs of torch igniter 10 and combustor 24.
Advantageously, torch igniter 10 can be operated with minimal fuel consumption during continuous operation. Limiting the fuel fed to combustion within torch igniter 10 can prevent a hot streak of combustion gases from entering combustor 24 and damaging combustor liner 22. Generally, inlet 62 intakes air at a variable rate that depends on engine pressurization and fuel injector 44 injects fuel at a rate that varies proportionally with the rate that air is taken in by inlet 62. For example, during a pre-takeoff startup of torch igniter 10, inlet 62 may intake air at a rate of approximately 10 lbs. per hour. However, during takeoff conditions or continuous operation, inlet 62 can intake air at a rate of approximately 400 lbs. per hour. The amount of fuel injected by fuel injector 44 is selected to provide an appropriate amount of fuel to form a stable air/fuel mixture in combustion chamber 16. One such arrangement allows fuel injector 44 to provide enough fuel such that the ratio of fuel to air in combustion chamber 16 is 10:1 at any point during operation. For example, fuel injector 44 may provide 1 lb. of fuel per hour during a pre-takeoff startup and may provide 40 lbs. per hour of fuel during takeoff or continuous operation. However, when air taken in through inlet 62 is sufficiently hot, less fuel may be required for continuous operation of torch igniter 10. Under these conditions, torch igniter 10 may be operated with an air to fuel ratio of 30:1 (approximately 15 lbs. of fuel per hour), further minimizing the amount of fuel consumed by torch igniter 10.
Air from within the high-pressure turbine case enters torch igniter 110 via inlets in tip section 130 (not shown) and along substantially similar flow paths as those present in torch igniter 10. Specifically, a portion of air from an inlet is diverted and travels through helical outlets 164 to cool the end of tip section 130. Air exits helical outlets 164 through combustor liner 122 into the interior of main combustor 123. The portion of air that is not diverted through helical outlets 164 travels through channels 128. Channels 128 have axially-extending helical sections surrounding igniter wall 138 in tip section 130 and combustion section 132 and a radially-extending section in elbow region 166. In the depicted example, channels 128 embedded within cap section 134 are not helical. A portion of air traveling through channels 128 is diverted through metering holes 168 downstream of the internal end of glow plugs 126 and the remainder of air traveling through channels 128 enters combustion chamber 116 through air swirl holes 170, which are disposed upstream of the internal end of glow plugs 126. Torch igniter 110 is capable of operating with a self-sustaining flame, as described previously with respect to torch igniter 10.
Elbow region 166 includes radial sections 175 and channels 176. Arrows 178 indicate the direction of airflow through elbow region 166. A portion of air leaving helical channels 128 in tip section 130 travels radially outward through radial sections 175 toward the helical section of channels 128 in combustion section 132. Another portion of air leaving helical channels 128 in tip section 130 is diverted through channels 176 and toward metering holes 168.
Air exiting elbow section 166 flows according to arrows 180. Specifically, air flowing through radial sections 175 toward cap section 134 turns to flow axially along combustion section 132. Channels 128 have a helical shape as they extend along combustion section 132.
Divider 460 is generally annular and extends from mixing nozzle 448 radially outward to igniter wall 462 in combustion section 464 of torch igniter 410. Quench holes 440 extend through igniter wall 462 in combustion section 464 of torch igniter 410 and are arranged in an annular pattern. Quench holes 440 may in some examples be canted with respect to an inner surface of igniter wall 462. Mixing nozzle 448 is annular and extends generally in the direction of flow through torch igniter 410. Mixing nozzle 448 is shown to have a uniform diameter and extends outward from divider 460 at approximately a 90° angle. However, it should be understood that mixing nozzle 448 can have a non-uniform diameter, can take a non-annular shape, and can extend from divider 460 at any suitable angle.
Up to 50% of airflow through channels 420 can be diverted through quench holes 440 to be used to cool hot combustion gases. To ensure that sufficient air remains to be used to cool torch igniter 410 and be used subsequently for combustion in combustion chamber 438, channels 420 can have substantially larger volume than channel 28 of torch igniter 10 or channels 128 of torch igniter 110, at least in the region of channels 420 connecting inlet 416 to quenching holes 440.
Similarly, to facilitate effective mixing and temperature quenching of air within quenching zone 450, outlet passage 454 can be sized to have a substantially larger volume than outlet passage 40 of torch igniter 10 or outlet passage 140 of torch igniter 110. Furthermore, elbow region 459 can be formed at a non-90° angle to expand the area available between divider 460 and elbow region 459 and thereby increase the volume available in quenching zone 450 to mix air flowing through quench holes 440 with hot combustion gases.
In examples of torch igniter 410 having aperture 680, quenching zone 650 extends axially from downstream face 682 of aperture 680 to downstream tip end 461. Aperture 680 has a circular cross section that is depicted as having a larger diameter than a diameter of outlet passage 454. However, it should be understood aperture 680 can have a diameter substantially the same as or smaller than the diameter of outlet passage 454, and further that aperture 680 can adopt any suitable shape for creating quenching zone 650 and channeling combustion gases from combustion chamber 438.
In summary, a torch igniter described herein can possess at least four distinct flow paths: (1) from inlets 172 to air swirl holes 170 and into combustion chamber 116; (2) from inlets 172 to metering holes 168 and into combustion chamber 116; (3) from inlets 172 through helical outlets 162 and tip holes 192 into a combustor; and (4) from inlets 172 into a quenching zone, such as quenching zones 450, 650, or 750. In examples of a torch igniter lacking a quenching zone and therefore only possessing flow paths (1), (2), and (3), the ratio of air flowing through flow paths (1), (2), and (3) is approximately 48/48/4, respectively. In examples of a torch igniter possessing all four flow paths, the ratio of air flowing through flow paths (1), (2), (3), and (4) is approximately 24/24/2/50, respectively. While the torch igniters described herein are described generally as having four distinct flow paths, it should be understood that the torch igniters described herein can be configured to flow air through any suitable number of flow paths, including more than four flow paths. Further, the torch igniters herein can be configured to have fewer than four flow paths.
Advantageously, the cooling arrangements disclosed herein allow for torch igniters 10, 110, or 410 to be formed from only metallic materials. In particular, the helical geometry of helical channels 128 and helical outlets 164 possessed by torch igniter 110 substantially improves the cooling of igniter wall 138 by increasing the surface area available for cooling, allowing for the construction of torch igniter 110 entirely from metallic components. This eliminates the need for the use of, for example, ceramic materials to shield metal components of the hot combustion gases generated by the torch igniters disclosed herein. Notably, forming a torch igniter that does not include a mixture of ceramic and metallic materials eliminates the need for additional support structures or vibration isolation features within the torch igniters disclosed herein and facilitates construction of the torch igniters using additive manufacturing. The torch igniters disclosed herein also do not require seals between metallic and ceramic components, further reducing the likelihood of leakage of hot combustion gases or cooling airflow. Forming torch igniters 10, 110, or 410 are formed as a monolithic structure further reduces the likelihood of leakage of hot combustion gases or cooling airflow.
More generally, all components of any torch igniter disclosed herein can be formed partially or entirely by additive manufacturing. For metal components (e.g., Inconel, steel, etc.) exemplary additive manufacturing processes include but are not limited to powder bed fusion techniques such as direct metal laser sintering (DMLS), laser net shape manufacturing (LNSM), electron beam manufacturing (EBM). Support-free additive manufacturing techniques, such as binder jetting, can also be used to form components of any torch igniter disclosed herein. Additive manufacturing is particularly useful in obtaining unique geometries (e.g., helical sections of channels 128 and helical outlets 164 of torch igniter 110) and for reducing the need for welds or other attachments (e.g., between tip section 130, combustion section 132, and cap section 134 of torch igniter 110). However, other suitable manufacturing process can be used. For example, any or all of tip section 30, combustion section 32, and cap section 34 can be fabricated separately and joined via later manufacturing steps (e.g., brazing, welding, or compression fitting) to form torch igniter 10. Similarly, in some examples, tip section 130, combustion section 132, and cap section 134 can in some examples be fabricated separately and joined via later manufacturing steps to form torch igniter 110.
The following are non-exclusive descriptions of possible embodiments of the present invention.
An embodiment of a torch igniter for a combustor of a gas turbine engine, wherein the torch igniter comprises a combustion chamber oriented about an axis, a cap defining the axially upstream end of the combustion chamber and oriented about the axis, a tip defining the axially downstream end of the combustion chamber, an igniter wall extending from the cap to the tip and defining a radial extent of the combustion chamber, a structural wall coaxial with and surrounding the igniter wall, an outlet passage defined by the igniter wall within the tip, and a cooling system. The combustion chamber has upstream and downstream ends defining a flow direction through the combustion chamber along the axis, the cap is configured to receive a fuel injector and a glow plug, and the outlet passage fluidly connects the combustion chamber to the combustor of the gas turbine engine. The cooling system comprises an air inlet formed within the structural wall, a first flow path disposed between the structural wall and the igniter wall and extending from the inlet to the cap, and an aperture extending transverse to the flow direction through the igniter wall. The air inlet is configured to intake a flow of air from a compressor section of the gas turbine engine. The first flow path is configured to receive a first portion of the air taken in by the inlet. The aperture directly fluidly connects the first flow path to the combustion chamber.
The torch igniter of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
A torch igniter for a combustor of a gas turbine engine according to an exemplary embodiment of the foregoing torch igniter, among other possible things includes a combustion chamber oriented about an axis, a cap defining the axially upstream end of the combustion chamber and oriented about the axis, a tip defining the axially downstream end of the combustion chamber, an igniter wall extending from the cap to the tip and defining a radial extent of the combustion chamber, a structural wall coaxial with and surrounding the igniter wall, an outlet passage defined by the igniter wall within the tip, and a cooling system. The combustion chamber has upstream and downstream ends defining a flow direction through the combustion chamber along the axis, the cap is configured to receive a fuel injector and a glow plug, and the outlet passage fluidly connects the combustion chamber to the combustor of the gas turbine engine. The cooling system comprises an air inlet formed within the structural wall, a first flow path disposed between the structural wall and the igniter wall and extending from the inlet to the cap, and an aperture extending transverse to the flow direction through the igniter wall. The air inlet is configured to intake a flow of air from a compressor section of the gas turbine engine. The first flow path is configured to receive a first portion of the air taken in by the inlet. The aperture directly fluidly connects the first flow path to the combustion chamber.
A further embodiment of the foregoing torch igniter, wherein the first flow path comprises a first section surrounding the combustion chamber and a second section disposed within the cap.
A further embodiment of any of the foregoing torch igniters, wherein the second section is configured to first flow air toward an axially upstream end of the cap and then to turn the flow of air at the axially upstream end of the cap to flow toward the downstream end of the torch igniter.
A further embodiment of any of the foregoing torch igniters, wherein the igniter wall is annular and a radius of the combustion chamber is greater than a radius of the outlet passage, forming an elbow region at a downstream end of the combustion chamber.
A further embodiment of any of the foregoing torch igniters, wherein the first flow path extends axially through the tip, radially through the elbow region, and axially through the combustion chamber.
A further embodiment of any of the foregoing torch igniters, further comprising a second flow path disposed between the structural wall and the igniter wall and extending from the inlet to a downstream end of the combustion chamber.
A further embodiment of any of the foregoing torch igniters, wherein the second flow path is configured to receive a second portion of air flowing taken in by the inlet.
A further embodiment of any of the foregoing torch igniters, wherein the tip is attached to the combustor, the outlet passage is fluidly connected to an interior volume of the combustor, the air inlet is positioned outside of the combustor in a high-pressure case of the gas turbine engine, and the air taken in by the air inlet is compressed air.
A further embodiment of any of the foregoing torch igniters, wherein the cooling system further comprises a tip hole in an exterior of the tip that directly fluidly connects the third flow path to the interior volume of the combustor, such that air flowing through the second flow path is able to flow into the combustor.
A further embodiment of any of the foregoing torch igniters, wherein the first flow path, second flow path, or first and second flow paths have a helical shape.
A further embodiment of any of the foregoing torch igniters, wherein the torch igniter is formed by additive manufacturing.
A further embodiment of any of the foregoing torch igniters, wherein at least two portions of the torch igniter are each formed monolithically and attached by an additional manufacturing step.
A further embodiment of any of the foregoing torch igniters, wherein the air inlet is disposed adjacent to the tip of the torch igniter.
A further embodiment of any of the foregoing torch igniters, wherein the torch igniter further comprises a glow plug received through the cap and the glow plug has a first end that extends into the combustion chamber and a second end opposite the first that extends away from the combustion chamber.
A further embodiment of any of the foregoing torch igniters, wherein the aperture is disposed in the igniter wall at a position upstream of the first end of the glow plug.
A further embodiment of any of the foregoing torch igniters, wherein the torch igniter further comprises a metering hole disposed in the igniter wall at a position downstream of the first end of the glow plug that directly fluidly connects the cooling channel to the combustion chamber at a position in the flow path before the aperture.
A further embodiment of any of the foregoing torch igniters, wherein the metering hole is configured to divert a third portion of the air flowing toward the aperture into the combustion chamber before it reaches the aperture.
A further embodiment of any of the foregoing torch igniters, wherein the igniter wall is annular and a radius of the combustion chamber is greater than a radius of the outlet passage, forming an elbow region at a downstream end of the combustion chamber; and the metering hole is disposed adjacent to the elbow region and is configured to flow the diverted third portion of the air across an interior portion of the igniter wall at the elbow region.
A further embodiment of any of the foregoing torch igniters, wherein the torch igniter further includes fins extending radially outward from the igniter wall to the structural wall that split the first flow path into a plurality of flow paths, wherein the fins are configured to conduct heat from the igniter wall.
A further embodiment of any of the foregoing torch igniters, wherein the fins are configured to transfer heat from the igniter wall to the structural wall and the structural wall is configured to act as a cooling sink.
A further embodiment of any of the foregoing torch igniters, further comprising a quench hole disposed at a downstream location of the combustion chamber.
A further embodiment of any of the foregoing torch igniters, wherein the quench hole fluidly connects the first flow path to the outlet passage, is configured to divert a portion of the air flowing through the first flow path to the outlet passage to cool combustion gases flowing through the outlet passage.
A further embodiment of any of the foregoing torch igniters, wherein the cap, combustion chamber, and tip are oriented about an axis and the direction of flow is coaxial with the axis.
An embodiment of a method of cooling a torch igniter in a gas turbine engine, wherein the method comprises intaking a flow of air from a compressor section of the gas turbine engine at an air inlet formed in a structural wall of an igniter, flowing a first portion of the air through a first flow path disposed between the structural wall and an igniter wall and flowing the first portion of the air into through an aperture that directly fluidly connects the first flow path to the combustion chamber. The structural wall extends coaxially with and surrounds an igniter wall. The igniter wall defining a combustion chamber within the torch igniter. The first flow path extends from the inlet toward a cap defining an upstream end of the torch igniter.
The method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations and/or additional components:
A method cooling a torch igniter in a gas turbine engine turbine engine according to an exemplary embodiment of the foregoing torch igniter including intaking a flow of air from a compressor section of the gas turbine engine at an air inlet formed in a structural wall of an igniter, flowing a first portion of the air through a first flow path disposed between the structural wall and an igniter wall and flowing the first portion of the air into through an aperture that directly fluidly connects the first flow path to the combustion chamber. The structural wall extends coaxially with and surrounds an igniter wall. The igniter wall defining a combustion chamber within the torch igniter. The first flow path extends from the inlet toward a cap defining an upstream end of the torch igniter.
A further embodiment of the foregoing method, wherein the igniter wall forms an outlet passage in a tip of the torch igniter, the outlet passage is disposed between and directly fluidly connects the combustion chamber to the combustor, the air inlet is positioned outside of the combustor in a high-pressure case of the gas turbine engine, and the air taken in by the air inlet is compressed air.
A further embodiment of any of the foregoing methods, further comprising flowing a second portion of the air through a second flow path disposed between the structural wall and the igniter wall.
A further embodiment of any of the foregoing methods, wherein the second flow path extends from the inlet to a tip defining a downstream end of the torch igniter.
A further embodiment of any of the foregoing methods, wherein the method further comprises flowing the second portion of the air into the interior volume of the combustor through a tip hole disposed at a downstream end of the tip.
A further embodiment of any of the foregoing methods, wherein the method further comprises metering the flow of air to the aperture by diverting some of the first portion of the air into the combustion chamber through a metering hole into the combustion chamber before flowing the air through the aperture, wherein the metering hole extends through the igniter wall.
While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.
This application is a continuation of U.S. application Ser. No. 17/089,236 filed Nov. 4, 2020 for “TORCH IGNITER COOLING SYSTEM” by J. Ryon and L. A. Prociw.
Number | Date | Country | |
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Parent | 17089236 | Nov 2020 | US |
Child | 17983691 | US |