Patent Application
20150354517
The present invention relates generally to turbine engines, and more particularly to injectors for turbine engines having a plurality of direct injection multipoint nozzles.
A turbine engine typically includes an outer casing extending radially from an air diffuser and a combustion chamber. The casing encloses a combustor for containment of burning fuel. The combustor includes a liner and a combustor dome, and an igniter is mounted to the casing and extends radially inwardly into the combustor for igniting fuel.
The turbine also typically includes one or more fuel injectors for directing fuel from a manifold to the combustor. Fuel injectors also function to prepare the fuel for mixing with air prior to combustion. Each injector typically has an inlet fitting connected either directly or via tubing to the manifold, a tubular extension or stem connected at one end to the fitting, and one or more spray nozzles connected to the other end of the stem for directing the fuel into the combustion chambers. A fuel passage (e.g., a tube or cylindrical passage) extends through the stem to supply the fuel from the inlet fitting to the nozzle. Appropriate valves and/or flow dividers can be provided to direct and control the flow of fuel through the nozzle. The fuel injectors are often placed in an evenly-spaced annular arrangement to dispense (spray) fuel in a uniform manner into the combustion chamber. Additional concentric and/or series combustion chambers each require their own arrangements of nozzles that can be supported separately or on common stems. The fuel provided by the injectors is mixed with air and ignited, so that the expanding gases of combustion can, for example, move rapidly across and rotate turbine blades in a gas turbine engine to power an aircraft, or in other appropriate manners in other combustion applications.
The present invention provides an injector having a plurality of injector modules that include a spray cup having a chamber and a plurality of radial air passages for directing air radially into the chamber, and a pressure swirl atomizer attached to the spray cup and having a fluid passage for directing fluid axially into chamber and an air passage for directing air axially into the chamber. By providing radial and axial air flow and axial fuel flow into the chamber, the fuel may be mixed to prevent local hot spots that lead to high NOx emissions, and a stable flame may be maintained without autoignition and flashback. The axial air flow also prevents recirculation zones from forming at a base of the spray cup, provides improved atomization and enhanced combustion.
According to one aspect of the invention, an injector is provided that includes a housing having a fluid channel for fluid, a plurality of injector modules fluidly connected to the fluid channel, each injector module including a spray cup having first and second open ends, a chamber defined between the ends, and a plurality of radial air passages extending through the spray cup for directing air radially inwardly into the chamber, and a pressure swirl atomizer attached to the spray cup at the first end, the pressure swirl atomizer including a body having a tip extending into the chamber, a fluid passage extending through the body for directing fluid in an axial direction into the chamber, and at least one air passage radially outwardly spaced from the fluid passage for directing air in the axial direction into the chamber, and a heatshield assembled to a downstream end of each injector module, the heatshield including a body for protecting the injector modules from combustion heat and a plurality of apertures located so as to allow the fluid from a corresponding injector module to be dispensed from the spray cup.
The plurality of apertures are spaced along a length of the heatshield in a direction perpendicular to the axial direction.
The plurality of injector modules are spaced from one another in the direction perpendicular to the axial direction along the length of the heatshield such that the injector modules float radially relative to an adjacent one of the plurality of injector modules.
The at least one air passage of each pressure swirl atomizer includes a plurality of circumferentially spaced air passages.
Each pressure swirl atomizer includes a plurality of projections extending radially outwardly from the body, and wherein the air passages are formed between adjacent ones of the plurality of projections.
The plurality of projections are angled relative to the axis of the spray cup to swirl the air in the air passage.
The plurality of radial air passages of each spray cup are circumferentially spaced.
The plurality of circumferentially spaced radial air passages include a plurality of sets of circumferentially spaced passages axially spaced from one another.
The air from the radial air passages and the axial air passage of each injector module combines with the fluid from the respective fluid passage and is directed out of the spray cup through the second open end.
According to another aspect of the invention, an injector module is provided that includes a spray cup having first and second open ends, a chamber defined between the ends, and a plurality of radial air passages extending through the spray cup for directing air radially inwardly into the chamber, and a pressure swirl atomizer attached to the spray cup at the first end, the pressure swirl atomizer including a body having a tip extending into the chamber, a fluid passage extending through the body for directing fluid in an axial direction into the chamber, and at least one air passage radially outwardly spaced from the fluid passage for directing air in the axial direction into the chamber.
The at least one air passage includes a plurality of circumferentially spaced air passages.
The pressure swirl atomizer includes a plurality of projections extending radially outwardly from the body, and wherein the air passages are formed between adjacent ones of the plurality of projections.
The plurality of projections are angled relative to the axis of the spray cup to swirl the air in the air passage.
The spray cup includes a flange extending radially outwardly from the second end.
The flange includes a plurality of air cooling holes for stagnation flow
The plurality of radial air passages are circumferentially spaced.
The plurality of circumferentially spaced radial air passages include a plurality of sets of circumferentially spaced passages axially spaced from one another.
The tip of the pressure swirl atomizer is conical.
The spray cup diverges from the first end to the second end.
The air from the radial air passages and the axial air passage combines with the fluid from the fluid passage and is directed out of the spray cup through the second open end.
The pressure swirl atomizer includes an inner body defining the fluid passage and an outer body surrounding the inner body, the outer body being attached to the first end of the spray cup.
A heatshield gap is provided between the inner and outer bodies heat shielding the fluid in the fluid passage to isolate the fluid from air surrounding the outer body.
According to another aspect of the invention, a plurality of injector modules are provided, each injector module including a spray cup having first and second open ends, a chamber defined between the ends, and a plurality of radial air passages extending through the spray cup for directing air radially inwardly into the chamber, and a pressure swirl atomizer attached to the spray cup at the first end, the pressure swirl atomizer including a body, a fluid passage extending through the body for directing fluid in an axial direction into the chamber, and at least one air passage radially outwardly spaced from the fluid passage for directing air in the axial direction into the chamber.
The plurality of injector modules are spaced from one another in a direction perpendicular to the axial direction such that the injector modules float radially relative to an adjacent one of the plurality of injector modules.
The body of each pressure swirl atomizer has a tip extending into the chamber of the spray cup.
According to still another aspect of the invention, an injector for distributing liquid sprays is provided, the injector including an inlet fitting including a port for receiving liquid, a stem supported by the fitting, the stem including an internal circuit fluidly connected to the port, at least one flow plate supported by the stem, the at least one flow plate including an internal passage connected to the internal circuit in the stem, a plurality of pressure swirl atomizers each having an upstream end attached to the at least one flow plate, a downstream end, and a fluid passage extending therethrough that is fluidly connected to the internal passage, a plurality of spray cups each having an upstream end attached to the downstream end of one of the plurality of pressure swirl atomizers, a downstream end, and a chamber into which the downstream end of one of the pressure swirl atomizers extends, and a heatshield attached to the downstream end of each of the plurality of spray cups.
The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings.
The principles of the present application have particular application to injectors for turbine engines and thus will be described below chiefly in this context. It will of course be appreciated, and also understood, that the principles of the invention may be useful in other applications where fluid, such as fuel, is mixed with air and distributed.
Referring now in detail to the drawings and initially to
A fuel injector, indicated generally at 30, is received within an aperture formed in the casing 12 and extends into the combustor 16. As shown in
Attached to the stem 36 and also surrounded by the heatshield is at least one plate, and as shown first and second flow plates 40 and 42 (
A plurality of rectangular, radially-extending openings may be formed in the dome 20 in an evenly spaced-apart arrangement around the dome 20 and corresponding to locations of openings through which the stem 36 extends for the injector modules 44 and heatshields 46 to extend through. The heatshields 46 interface with the dome 20 to provide an axial seal that is loaded with a pressure drop during operation to control air leakage. It will be appreciated that while a number of injectors 30 are shown in an evenly-spaced annular arrangement, the number and location, and spacing of the injectors 30 may vary depending upon the application.
Turning now to
As noted above, surrounding the stem 36 is the housing or stem heatshield 38 that is spaced from the stem 36 to provide an air gap. The stem heatshield 38 also surrounds the first flow plate 40 attached to a downstream end of the stem 36, and the second flow plate 42 attached to a downstream end of the first flow plate 40. Attached to the downstream end of the second flow plate 42 are the plurality of injector modules 44, which are arranged in three linear groups, a first end group 60, a second end group 64 and a center group 62. The groups may be arranged at an angle relative to one another, such as a forty-five degree angle, to reduce interaction of the spray exiting the injector modules in one of the adjacent groups and to enhance flame stability.
As shown in
The second and third flow passages 72 and 74 serve as first and second main circuits typically for use separately or together as the engine reaches medium to maximum power conditions. The second flow passage 72 directs the fluid to a plurality of second flow passage 78a-78d in the second flow plate 42, which direct the fluid to the remaining injector modules 44b-44e, respectively, in the center group 62 of injector modules. The third flow passage 74 directs the fluid to a plurality of third flow passages, two of which are shown at 80a and 80b in the second flow plate 42 in
Referring now to the heatshield 46 in detail, the heatshield 46 is attached to a downstream end of each injector module 44 for protecting the injector modules 44 from combustion heat, such as by restricting air flow around the modules. The heatshield 46 includes a body 90, which may include a thermal barrier coating and may optionally have a plurality of cooling holes 92 extending therethrough for relatively cool air to flow through to provide effusion cooling on a surface of the heatshield 46, and a plurality of openings 94 located so as to allow the fluid from a corresponding injector module 44 to be dispensed into the combustor 16.
The body 90 is formed by three elongated heatshield segments 100, 102, and 104 integrally formed or coupled in any suitable manner, each of which has a somewhat rectangular shape with an outer planar surface and adjoining and contiguous side edges. Each heatshield segment includes a plurality of the openings 94 arranged in respective linear, planar arrays, spaced evenly along a length of the respective segment 100, 102 and 104, and along about the median line of the segment. The injector modules 44 are correspondingly spaced along a length of the respective segment 100, 102, and 104 so that the injector modules 44 can float radially relative to adjacent injector modules 44 along a corresponding segment 100, 102, and 104 to relieve thermal stress, and can expand at high temperatures thereby filling the gaps between the injector modules. The injector modules may also float axially, for example by growing axially due to heat and moving the heatshield accordingly, and may also float in a transverse direction, for example by growing in the transverse direction due to heat. It will be appreciated that while shown as being in linear, planar arrays, the openings 94 may be arranged in any suitable arrangement. It will also be appreciated that each injector module may include its own heatshield that may be coupled to adjacent heatshields in any suitable manner.
The heatshield 46 may be attached to the injector modules 44 in any suitable manner, such as by sliding the injector modules 44 into grooves 106 and 108 formed along a backside of the body 90. In an embodiment, the grooves 106 and 108 may be formed along the backside of each segment 100, 102, and 104, allowing the injector modules 44 to be radially spaced. The injector modules 44 may also be attached such that a portion of a second end of each injector module 44 is axially spaced from the heatshield 46, thereby defining an axial cooling gap 110 as shown in
Turning now to
The spray cup 120 also includes a flange 132 extending radially outwardly from the second end 126. First and second sides of the flange 132 may be received respectively in the grooves 106 and 108 in the heatshield 46 to secure the spray cup 120 to the heatshield. The flange 132 may include a plurality of holes 134 that may provide for stagnation cooling flow on the back side of the heatshield 46, and communicate with the cooling holes 92 in the heatshield 46 through the gap 110 to provide for effusion cooling flow through the heatshield 46. The cooling holes 92 provide for effusion cooling to reduce heat transfer between the combustion products and the heatshield 46, thereby reducing temperature gradients and thermal stresses in the spray cup and reducing wetted wall temperature in the atomizer tip.
Referring now to the pressure swirl atomizer 122, the pressure swirl atomizer 122 extends through the stem heatshield 38 and has a first end 140 attached to the flow plate 42, such as by brazing, and a second end 142 attached to the spray cup 120 at the first end 124, such as by brazing. The pressure swirl atomizer 122 includes a body 144, herein referred to as an outer body 144 that has a tip 148 extending into the chamber 128, an orifice body 146 that is surrounded by the outer body 144, a fluid passage 150 extending through the orifice body 146 for directing fluid, such as fuel, in an axial direction into the chamber 128, and at least one air passage 152 radially outwardly spaced from the fluid passage 150 for directing air around the pressure swirl atomizer 122 in the axial direction into the chamber 128.
The outer body 144 has at the second end 142 a plurality of circumferentially spaced projections 160 extending radially outwardly from the outer body 144. The at least one air passage 152, and in the illustrated embodiment a plurality of circumferentially spaced air passages 152, are formed between adjacent ones of the plurality of projections 160. The plurality of projections 160 may be straight or may be angled relative to the axis of the spray cup 120 as shown to swirl the air in the air passages 152. It will be appreciated that the projections may be formed according to known vane configurations, such as aerodynamic or curved helical vanes.
The orifice body 146 includes an outer wall 170 radially inwardly spaced from an inner wall 172 of the outer body 144 substantially along the length of the orifice body 146 to provide a heatshield gap 174 between the orifice body 146 and the outer body 144. The heatshield gap 174 shields the fluid in the fluid passage 150 by thermally isolating the fluid from air, such as the air flowing around the outer body 144 towards the air passages 152. To couple the orifice body 146 to the outer body 144, the orifice body includes a portion 176 at a first end 178 of the orifice body 146 that may be coupled to the inner wall 172 of the outer body 144 in any suitable manner, such as by brazing.
Disposed within the orifice body 146 are a plug 180 and a plug retainer 182. The plug retainer 182 abuts the plug 180 and is coupled to an inner wall 184 of the orifice body 146 in any suitable manner, such as by threads 188 that mate with threads 186 on the orifice body 146, to retain the plug 180 within the orifice body 146. The plug 180 includes a plurality of circumferentially spaced projections 190 extending radially outwardly from the plug 180 and contacting the inner wall 184 of the orifice body. A plurality of slots 192 are formed between the projections 190 to allow fluid to flow around the plug 180 and to swirl the fluid flowing past the plug 180. The plug retainer 182 includes a through passage 194 allowing fluid flow through the plug retainer 182. The through passage 194 in the plug retainer and the slots 192 of the plug define the fluid passage 150 through the orifice body 146.
The orifice body 146 also includes a tip 196 at a second end 198 of the orifice body 146. Both the second end 142 of the outer body 144 and the second end 198 of the orifice body may be conical, and the second end 198 of orifice body 146 converges within the outer body 144. The tip 196, which extends axially past the conical portion of the second end 196, extends through an opening in the tip 148 of the outer body 144 and past the tip 148 into the chamber 128. In this way, fluid flowing through the slots 192 converges towards the center of the orifice body 146 and is directed into the center of the spray cup 120. The distance the tips 148 and 196, and thus the fluid exit of the pressure swirl atomizer 122, extend into the chamber 128 may be varied based on application such that the fluid exit is recessed, flush, or protruding relative to the radial air passages 130 to control spray dispersion and combustion performance.
The micro-mixing injector modules 44 maintain lean combustion at high power conditions and may be straight, converging or diverging in a direction of flow, such as straight injector modules having non-swirling axial through flow, diverging modules having non-swirling radial inflow, etc. The micro-mixing injector modules may include swirling air inlets providing swirling through flow, non-swirling air inlets providing non-swirling through flow, or a combination thereof, where the swirl can be both clockwise or counter clockwise about the flow direction.
The micro-mixing injector modules may be fabricated in any suitable manner, such as by macrolamination, rapid prototyping, casting, machining, a combination thereof, etc., and may be formed by one or more components. The pressure swirl atomizers may be fabricated as a separate assembly from the spray cups, or integrated into the stem or spray cup. The heatshield may be fabricated in any suitable manner, such as by macrolamination, rapid prototyping, casting, machining, a combination thereof, etc., may be formed by one or more components, an may be integral with the micro-mixing injector modules.
During operation of the injector 30, fuel flows from a fuel supply through the valve housing and depending on engine operation, flows through one or more of the flow passages in the stem 36 to the pilot and/or main circuits. The fuel flows through the flow passages in the stem 36 into the respective flow passages 70, 72 and 74 and into the fluid passage 150 in the pressure swirl atomizer 122. The fuel is then directed axially out of the tip 196 in the orifice body 146 into the chamber 128. At the same time, air surrounding the injector 30 flows through the air passages 152 and is directed axially into the chamber 128, and the air flows through the radial air passages 130 radially inwardly into the chamber 128. The air from the air passages 130 and 152 mixes with the fuel in the chamber 128 and is directed out of the spray cup 120 at the second open end 126, through the opening 94 in the heatshield 46, and into the combustor 16.
By providing axial air flow and axial fuel flow into the chamber 128, the injector modules 44 provide improved atomization, enhanced combustion and increased effective area. By providing radial and axial air flow and axial fuel flow into the chamber 128, the fuel may be mixed to prevent local hot spots that lead to high NOx emissions, and a stable flame may be maintained without autoignition and flashback. The axial air flow also prevents recirculation zones from forming at the first end 124 of the spray cup 120, provides improved atomization, and enhanced combustion.
Turning now to
The micro-mixing injector module 244 includes a spray cup 320 and a pressure swirl atomizer 322 attached to the spray cup or integrally formed with the spray cup 320. The pressure swirl atomizer 322 extends through the stem heatshield 38 and has a first end 340 attached to the flow plate 42, such as by brazing, and a second end 342 attached to the spray cup 320 at the first end 324, such as by brazing. The pressure swirl atomizer 322 includes a body 344, herein referred to as an outer body 344, having a tip 348 extending into the chamber 328, an orifice body 346 surrounded by the outer body 344, a first fluid passage 350 extending through the orifice body 346 for directing fluid, such as from a pilot circuit in an axial direction into the chamber 328, at least one air passage 352 radially outwardly spaced from the fluid passage 350 for directing air in the axial direction into the chamber 328, and a second fluid passage 354 radially outwardly spaced from the fluid passage 350 for directing fluid, such as a main circuit, in an axial direction into the chamber 328.
The second fluid passage 354 is provided between an outer wall 370 of the orifice body 346 and an inner wall 372 of the outer body 344. The orifice body 346 includes a plurality of circumferentially spaced projections 376 at a first end 378 of the orifice body 346 that may be coupled to the inner wall 372 of the outer body 344 in any suitable manner, such as by brazing. Slots (not shown) are provided between the projections 376 for the fluid to flow through to the second fluid passage 354. The orifice body 346 also includes a tip 396 at a second end 398 of the orifice body 346 that extends axially past the conical portion of the second end 396 and extends through an opening in the tip 348 of the outer body 344 past the tip 348 into the chamber 328. The tip 396 is spaced from the tip 348 such that fluid in the second fluid passage 354 may exit through the space between the tips into the chamber 328.
Turning now to
The micro-mixing injector module 444 includes a spray cup 520 and a pressure swirl atomizer 522 attached to the spray cup or integrally formed with the spray cup 520. The pressure swirl atomizer 522 extends through the stem heatshield 38 and has a first end 540 attached to the flow plate 42, such as by brazing, and a second end 542 attached to the spray cup 520 at the first end 524, such as by brazing. The pressure swirl atomizer 522 includes a body 544, herein referred to as an outer body 544, having a tip 548 extending into the chamber 528, an orifice body 546 surrounded by the outer body 544, a fluid passage 554 provided between an outer wall 570 of the orifice body 546 and an inner wall 572 of the outer body 544 for directing fluid in an axial direction into the chamber 528, and at least one air passage 552 radially outwardly spaced from the fluid passage 554 for directing air in the axial direction into the chamber 528.
The orifice body 546 includes a plurality of circumferentially spaced projections 576 at a first end 578 of the orifice body 546 that may be coupled to the inner wall 572 of the outer body 544 in any suitable manner, such as by brazing. Slots (not shown) are provided between the projections 576 for the fluid to flow through to the fluid passage 554. The orifice body 546 also includes a tip 596 at a second end 598 of the orifice body 546 that extends axially past the conical portion of the second end 596 and extends through an opening in the tip 548 of the outer body 544 past the tip 548 into the chamber 528. The tip 596 is spaced from the tip 548 such that fluid in the fluid passage 554 may exit through the space between the tips into the chamber 528.
Turning now to
Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
This application claims the benefit of U.S. Provisional Application No. 61/748,308 filed Jan. 2, 2013, which is hereby incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2013/078431 | 12/31/2013 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 61748308 | Jan 2013 | US |
