Combustor head

Abstract

The invention is entitled "Combustor Head". A combustor head for a fuel manifold, the combustor head comprising: a main fuel injection injector; a pilot fuel injection injector; a fuel source; a first isolation valve connected to the fuel source; and a staging valve. The staging valve is connected to the first isolation valve and the staging valve has a main fuel conduit connected to the main fuel injection injector and a pilot fuel conduit connected to the pilot fuel injection injector. The first isolation valve and the staging valve are connected in series such that fuel from the fuel source must pass through the first isolation valve before reaching the staging valve.

Description

Technical Field

[0001] This disclosure relates to a combustor head for a fuel manifold, a fuel manifold for a gas turbine engine, and a gas turbine engine. Background Technology

[0002] Multistage combustors are specifically used in lean-burn fuel systems of gas turbine engines to reduce unwanted emissions while maintaining thermal efficiency and flame stability. For example, a duplex fuel injector has pre-injection and main injection fuel manifolds that provide pre-injection and main injection exhaust orifices for the injector. Under low-power conditions, only the pre-injection stage is activated, while under higher power conditions, both the pre-injection and main injection stages are activated. The fuel used for the manifold is typically sourced from a pumped and metered supply. If the pre-injection and main injection stages are supplied by separate fuel manifolds, a diversion valve can be provided to selectively split the metered fuel supply between the manifolds according to the needs of a given stage.

[0003] A typical annular burner has a circumferential arrangement of burner heads, each associated with a corresponding pre-injection feed and main injection feed extending from a circumferentially extending pre-injection and main injection manifold. Each burner head typically has a nozzle that forms a fuel injector that discharges fuel into the burner's combustion chamber, a feed arm for transferring fuel to the burner head, and a connector located outside the burner at which the pre-injection and main injection feeds enter the feed arm. Inside the nozzle, a check valve, known as a flow regulation valve (FSV), is typically associated with each of the pre-injection and main injection feeds to maintain the filling manifold during degradation and shutdown. The FSV also prevents fuel from flowing into the injector nozzle when the supply pressure is less than the opening pressure (i.e., less than a given difference between the manifold pressure required to open the FSV and the burner gas pressure).

[0004] During pre-injection-only operation, the diverter valve directs only the fuel flow for the combustor through the pre-injection fuel circuit (i.e., the pre-injection manifold and the feed). Therefore, controlling the temperature in the degraded (i.e., main injection) fuel circuit is standard practice to prevent coking due to heat gain from the hot engine casing. One known method, for example, is to provide a separate recirculation manifold designed to keep the fuel in the main injection manifold cooled when deselected. This is achieved by keeping the fuel in the main injection manifold in motion, although the cooling flow must also be maintained in the recirculation manifold during main injection operation to avoid coking.

[0005] However, a problem with such systems is how to adapt the main injection FSV failure to the open state. In pre-injection only operation, such failure can cause cooling flow to pass through the failed-to-open FSV and through a main injection injector into the combustor as the cooling flow passes through the recirculation manifold and main injection manifold, resulting in thermal traces that can damage the nozzles and turbine. In both pre-injection and main injection operation, such failure can cause a drop in pressure in the main injection manifold, which shuts down other main injection FSVs on the main injection manifold. A possible result is again a higher proportion of the total main injection flow passing through the failed-to-open FSV to a single injector, resulting in thermal traces that can damage the nozzles and turbine.

[0006] In principle, such failure modes can be detected through appropriate thermocouple arrangements, for example, to detect heat marks. However, this type of temperature measurement device itself may have reliability issues.

[0007] UK Patent Application No. GB ​​2557601 A describes a fuel supply system comprising separate pre-injection and main-injection fuel manifolds, each delivering fuel to a pre-injection fuel injector and a main-injection fuel injector, respectively. A diverter valve is used to control the amount of fuel delivered to each manifold.

[0008] US Patent 7036302 B2 describes a fuel nozzle that includes pre-injection and main injection fuel nozzle valves connected to a single fuel supply manifold. Both valves are spring-biased and controlled by a pressure differential between a signal circuit and the fuel supply manifold pressure. If the spring in either valve fails, nothing prevents fuel from flowing through the associated nozzle valve.

[0009] The aim is to address the shortcomings of existing technologies and provide a fuel manifold arrangement that allows for precise control of fuel flow to the fuel injectors while reducing the likelihood of unwanted fuel leakage into the combustion chamber. Summary of the Invention

[0010] According to this disclosure, a burner head for a fuel manifold is provided, the burner head comprising: a main injection fuel injector; a pre-injection fuel injector; a fuel source; a first isolation valve connected to the fuel source; and a stage valve connected to the first isolation valve, the stage valve having a main injection fuel conduit connected to the main injection fuel injector and a pre-injection fuel conduit connected to the pre-injection fuel injector; wherein the first isolation valve and the stage valve are connected in series such that fuel from the fuel source must pass through the first isolation valve before reaching the stage valve.

[0011] Compared to existing burner heads, this type of burner achieves improved functionality while reducing the risk of engine damage caused by known failure modes.

[0012] A second isolation valve can be installed in the burner head. Adding a second isolation valve means that the burner head cannot release fuel to the main injection fuel injector unless fuel is already flowing to the pre-injection fuel injector. This also means that fuel flow to the main injection fuel injector can be completely cut off, even if fuel is flowing to the pre-injection fuel injector.

[0013] The first and second isolation valves can be controlled by solenoids, and the stage valve can be controlled by an electric motor. Alternatively, the first and second isolation valves and the stage valve can be pressure valves.

[0014] The burner head may be equipped with a valve control module connected to the first isolation valve, the second isolation valve, and the stage valve. The valve control module allows for a reduction in the number of wiring harnesses required for control functions, and thus reduces system weight and drive complexity.

[0015] The force required to open the first isolation valve at the burner head can differ from the force required to open the second isolation valve. The force required to open the first isolation valve can be less than the force required to open the second isolation valve. A single spring can be used to provide different forces to the first and second isolation valves.

[0016] In addition, a fuel manifold for a gas turbine engine is provided, the fuel manifold including one or more burner heads according to the present disclosure.

[0017] In addition, a gas turbine engine including a fuel manifold comprising one or more combustor heads according to the present disclosure is provided. Attached Figure Description

[0018] The implementation scheme will now be described by way of example only, with reference to the accompanying drawings, in which:

[0019] Figure 1 This is a cross-sectional side view of a gas turbine engine;

[0020] Figure 2 yes Figure 1 A close-up cross-sectional side view of the upstream section of the gas turbine engine shown.

[0021] Figure 3 yes Figure 1 and Figure 2 A partial cross-sectional view of the gearbox of the gas turbine engine shown;

[0022] Figure 4 A schematic diagram of a fuel manifold according to an embodiment of the present disclosure is shown;

[0023] Figure 5 A schematic diagram of a burner head arrangement structure according to a first embodiment of the present disclosure is shown;

[0024] Figure 6 A schematic diagram of an alternative burner head arrangement according to a first embodiment of the present disclosure is shown;

[0025] Figure 7 A schematic diagram of a second alternative burner head arrangement according to a first embodiment of the present disclosure is shown;

[0026] Figure 8 A schematic diagram of a burner head according to a second embodiment of the present disclosure is shown;

[0027] Figure 9 A schematic diagram of an alternative burner head according to a second embodiment of the present disclosure is shown;

[0028] Figure 10 A schematic diagram of a burner head according to a third embodiment of the present disclosure is shown;

[0029] Figure 11 A schematic diagram of an alternative burner head according to a third embodiment of the present disclosure is shown;

[0030] Figure 12 A schematic diagram of a burner head according to a fourth embodiment of the present disclosure is shown;

[0031] Figure 13 A schematic diagram of a second alternative burner head according to a third embodiment of the present disclosure is shown;

[0032] Figure 14 A schematic diagram of a burner head according to a fifth embodiment of the present disclosure is shown; and

[0033] Figure 15 A schematic diagram of a burner head according to a sixth embodiment of the present disclosure is shown. Detailed Implementation

[0034] Aspects and embodiments of this disclosure will now be discussed with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art.

[0035] Figure 1A gas turbine engine 10 with a main axis of rotation 9 is shown. The engine 10 includes an intake 12 and a propulsion fan 23 that generates two airflows: a core airflow A and a bypass airflow B. The gas turbine engine 10 includes an engine core 11 that receives the core airflow A. The engine core 11 includes, in axial-flow series, a low-pressure compressor 14, a high-pressure compressor 15, a combustion device 16, a high-pressure turbine 17, a low-pressure turbine 19, and a core exhaust nozzle 20. A nacelle 21 surrounds the gas turbine engine 10 and defines a bypass duct 22 and a bypass exhaust nozzle 18. The bypass airflow B flows through the bypass duct 22. The fan 23 is attached to and driven by the low-pressure turbine 19 via a shaft 26 and a rotary gearbox 30.

[0036] In operation, the core airflow A is accelerated and compressed by the low-pressure compressor 14 and directed to the high-pressure compressor 15 for further compression. The compressed air discharged from the high-pressure compressor 15 is directed to the combustion device 16, where it is mixed with fuel and combusted. The resulting thermal combustion products then expand through the high-pressure turbine 17 and the low-pressure turbine 19 before being discharged through the core exhaust nozzle 20, thereby driving the high-pressure turbine and the low-pressure turbine to provide some propulsive thrust. The high-pressure turbine 17 drives the high-pressure compressor 15 via a suitable interconnecting shaft 27. The fan 23 typically provides most of the propulsive thrust. The rotary gearbox 30 is a reduction gearbox.

[0037] Figure 2 An exemplary arrangement of a geared fan gas turbine engine 10 is shown. The low-pressure turbine 19 (see [reference]) Figure 1 A drive shaft 26 is connected to the sun gear or sun gear 28 of the planetary gear arrangement 30. A plurality of planet gears 32 mesh with the sun gear 28 radially outward, and are connected together by a planet carrier 34. The planet carrier 34 constrains the planet gears 32 to precess synchronously around the sun gear 28, while simultaneously causing each planet gear 32 to rotate about its own axis. The planet carrier 34 is connected to a fan 23 via a connecting rod 36 to drive the fan to rotate about the engine axis 9. A ring gear or ring gear 38 meshes with the planet gears 32 radially outward, and is connected to a fixed support structure 24 via a connecting rod 40.

[0038] It should be noted that the terms "low-pressure turbine" and "low-pressure compressor" as used herein may refer to the lowest-pressure turbine stage and the lowest-pressure compressor stage (i.e., excluding fan 23), and / or the turbine stage and compressor stage connected together by an interconnecting shaft 27 having the lowest rotational speed in the engine (i.e., excluding the gearbox output shaft driving fan 23). In some literature, the terms "low-pressure turbine" and "low-pressure compressor" mentioned herein may alternatively be referred to as "intermediate-pressure turbine" and "intermediate-pressure compressor." In the case of such alternative nomenclature, fan 23 may be referred to as the first or lowest-pressure compression stage.

[0039] exist Figure 3 The rotary gearbox 30 is shown in more detail by way of example. Each of the sun gear 28, planetary gear 32, and ring gear 38 includes teeth surrounding its periphery for meshing with other gears. However, for clarity, Figure 3 Only exemplary portions of the teeth are shown. Four planetary gears 32 are shown, but it will be apparent to those skilled in the art that more or fewer planetary gears 32 can be provided within the scope of this disclosure. Practical applications of the planetary gearbox 30 typically include at least three planetary gears 32.

[0040] exist Figure 2 and Figure 3 The planetary gearbox 30 shown by way of example is a planetary type, in which the planet carrier 34 is connected to the output shaft via a connecting rod 36, and the ring gear 38 is fixed. However, any other suitable type of planetary gearbox 30 can be used. As another example, the planetary gearbox 30 can be a stellar arrangement, in which the planet carrier 34 remains fixed, allowing the ring gear (or gear ring) 38 to rotate. In such an arrangement, the fan 23 is driven by the ring gear 38. As yet another alternative example, the gearbox 30 can be a differential gearbox, in which both the ring gear 38 and the planet carrier 34 are allowed to rotate.

[0041] It should be understood that Figure 2 and Figure 3 The arrangement shown is merely exemplary, and various alternatives are within the scope of this disclosure. By way of example only, any suitable arrangement can be used to position the gearbox 30 within the engine 10 and / or for connecting the gearbox 30 to the engine 10. As another example, the connection between the gearbox 30 and other components of the engine 10 (such as the input shaft 26, output shaft, and mounting structure 24) (such as...) Figure 2The connecting rods 36 and 40 in the example can have any desired level of stiffness or flexibility. In another example manner, any suitable arrangement of bearings between the rotating and stationary parts of the engine (e.g., between the input and output shafts from the gearbox and a stationary structure such as the gearbox housing) can be used, and this disclosure is not limited to... Figure 2 The exemplary arrangement is as follows. For example, in the case where the gearbox 30 has a stellar arrangement (as described above), those skilled in the art will readily understand that the arrangement of the output link, support link, and bearing positions is generally different from that of the gearbox 30. Figure 2 The arrangement structure is shown as an example.

[0042] Therefore, this disclosure extends to gas turbine engines having any arrangement of gearbox type (e.g., star or planetary gear), support structure, input and output shaft arrangement, and bearing location.

[0043] Optionally, the gearbox may drive additional and / or alternative components (e.g., a medium-pressure compressor and / or a booster compressor).

[0044] Other gas turbine engines to which this disclosure is applicable may have alternative configurations. For example, such engines may have an alternative number of compressors and / or turbines and / or an alternative number of interconnecting shafts. In another example, Figure 1 The gas turbine engine shown has split nozzles 18 and 20, meaning that the flow through the bypass duct 22 has its own nozzle 18, which is separate from and radially located outside the core exhaust nozzle 20. However, this is not limiting, and any aspect of this disclosure can also be applied to engines in which the flow through the bypass duct 22 and the flow through the core 11 are mixed or combined before (or upstream of) a single nozzle, which may be referred to as a mixing nozzle. One or both nozzles (whether mixing or splitting) may have a fixed or variable area. While the described example relates to a turbofan engine, this disclosure is applicable to, for example, any type of gas turbine engine, such as an open rotor (where the fan stage is not surrounded by a nacelle) or, for example, a turboprop engine. In some arrangements, the gas turbine engine 10 may not include a gearbox 30.

[0045] The geometry of the gas turbine engine 10 and its components are defined by a conventional shaft system, including the axial direction (aligned with the axis of rotation 9) and the radial direction (in... Figure 1 The direction from bottom to top) and the circumferential direction (perpendicular to) Figure 1 (Page in the view). The axial, radial, and circumferential directions are perpendicular to each other.

[0046] Turning more specifically to the burner head of this disclosure, which can be used, for example, in the gas turbine of a geared turbofan engine as described above.

[0047] Figure 4 A basic arrangement of a fuel manifold 50 compatible with any of the embodiments described herein is shown. The fuel manifold has a ring configuration suitable for positioning around the periphery of the gas turbine engine combustor section 16. A fuel source 52 is present to the manifold, and at multiple points around the manifold, it terminating inward extensions in combustor heads 54, such as those described herein. It should be noted that Figure 4 The arrangements shown are illustrative only, and other arrangements of the burner heads are possible. For example, the burner heads may extend axially away from the manifold, such that they point out of the plane containing the fuel manifold, or they may extend away from the manifold at a certain intermediate angle, providing a suitable location for injecting fuel into the core region of the burner. Thus, the fuel manifold provides a fuel source for each burner head. The burner heads of the manifolds do not necessarily have the same design. In fact, in some cases, it may be advantageous to have burner heads with different designs at different locations around the fuel manifold. Alternative arrangements of the manifold are possible, and one or more manifolds according to this disclosure can be used within a single gas turbine engine.

[0048] Figure 5 A first embodiment of the combustor head 54 arrangement of this disclosure is shown. The combustor head has an isolation valve 60 and a stage valve 62 arranged in series. The first valve is the isolation valve 60, and the second valve is the stage valve 62, in the order of fuel flow. The purpose of the isolation valve is to provide a flow control mechanism that can be opened to allow fuel from fuel source 52 to flow to the stage valve 62, or closed in a liquid-tight manner to prevent fuel from flowing to the stage valve. For example, the isolation valve 60 may have only two states: open, allowing fuel to flow through the isolation valve, and closed, preventing fuel from flowing through the isolation valve. Alternatively, it may have three states: open, allowing fuel to flow only to the pre-injection fuel injector 64; open, allowing fuel to flow to both the pre-injection 64 and the main injection 66 fuel injectors; and closed, preventing fuel from flowing to either the pre-injection or the main injection fuel injector. The purpose of the stage valve is to control the ratio of fuel flowing to the pre-injection fuel injector to the main injection fuel injector. The optimal ratio is determined based on various factors known in the art, such as ambient temperature and mission phase (e.g., takeoff, climb, cruise, etc.).

[0049] The isolation valve 60 receives fuel flow from the fuel source 52 and sends it to the stage valve 62 via the intervalve connection 68. Figure 5In this embodiment, the position of the isolation valve 60 is controlled by a control flow from the control manifold 70. The fuel manifold 50 supplies fuel for combustion and also supplies fuel pressure to help close the isolation valve 60 and the stage valve 62. The control manifold 70 provides fuel pressure that pushes the isolation valve 60 toward its open position. The control manifold also applies pressure to the stage valve, directing the main jet flow to the main injection fuel injector 66. Control of the valve position is based on the difference between the pressure from the control manifold and the pressure from the fuel manifold. For example, the isolation valve may include a spring (not shown) that defaults to holding the isolation valve 60 closed. The fuel source manifold 52 sets a default pressure level that the pressure of the fuel from the control manifold 70 must overcome in addition to overcoming the force of the spring to open the isolation valve 60. Using pressure control to control the position of the fuel valve is well known in the art. The pressure control method optionally includes measuring the differential pressure between the fuel source and the control manifold, which may also be supplied by the fuel source.

[0050] When the isolation valve 60 connects to the intervalve connection 68, the stage valve 62 receives fuel from the isolation valve through the intervalve connection. Figure 5 In one embodiment, the intervalve connection has a diversion section, such that the fuel flow is divided into a pre-injection flow for the pre-injection fuel injector 64 and a main injection flow for the main injection fuel injector 66. A stage valve 62 controls the fuel flow to the pre-injection fuel injector and the main injection fuel injector. The position of the stage valve 62, and therefore the fuel flow to the pre-injection fuel injector and the main injection fuel injector, can be controlled by fluid pressure from the control manifold 70, thereby actuating the stage valve to open. Here, a spring within the stage valve 62 (if present) and a portion of the flow pressure from the fuel source 52 actuate the valve to close. A dynamic seal separates the control pressure region, the pre-injection stage region, the main injection stage region, and the fuel source flow region.

[0051] like Figure 5 As shown, the control flow to the isolation valve 60 and the stage valve 62 of a given burner can originate from the same control manifold 70. One or more control flows can control the isolation valves and stage valves of different groups of burner heads 54 on the manifold 50.

[0052] Figure 6 An alternative embodiment is shown in which the isolation valve 60 and stage valve 62 of a given combustor head 54 are controlled by different control flow sources. A first control manifold 70 supplies pressure to the isolation valve 60, and a second control manifold 72 supplies pressure to the stage valve 62. Control of the isolation valve 60 and stage valve 62 of different sets of combustor head 54 can be mixed between the same or different control flow sources 70, 72 to provide maximum advantage in engine operability under flight envelope, operating conditions, and weather conditions.

[0053] Importantly, relative to each embodiment described herein, the presence of a series-connected isolation valve 60 and a staged valve 62 ensures that even if any one of the valves fails, some degree of control over the fuel flow through the burner head 54 remains possible. Prior art designs use parallel manifolds to supply fuel to the main injection and pre-injection fuel injectors, with each manifold having a single isolation or staged valve to control the flow into the manifold. A staged or dispatched valve located at the burner head then controls the fuel flow to the main and pre-injection fuel injectors. In such prior art designs, if the staged or dispatched valve in the burner head fails, the fuel flow to the main and / or pre-injection fuel injectors at the burner head cannot be controlled without cutting off fuel to the entire manifold. In contrast, the burner head design shown here mitigates this potential problem. If the staged valve fails, the isolation valve can be used to cut off all or part of the fuel flow to the affected burner head. Similarly, if the isolation valve fails, only a single burner head is affected, and the staged valve can still be used to control any residual flow through the burner head. Therefore, compared with existing technologies, the consequences of any such failures can be greatly reduced; the risk of unintended increases in fuel flow during engine operation is minimized, and the risk of excessive fuel flow to individual burners is eliminated.

[0054] It is evident that the embodiments described herein can be applied to the entire fuel system of a gas turbine engine or any part of a system comprising at least one set of combustor heads. For example, in a particular engine design, it may be advantageous for some combustors to operate continuously while others can switch under specific operating conditions. This can facilitate combustor operation modes in engines of any size or dimensions.

[0055] Figure 7 A second alternative version of the first embodiment is shown, the only difference being that the isolation valve 60 and the stage valve 62 are controlled electronically instead of by pressure. In this embodiment, the isolation valve 60 is controlled by a solenoid 74, and the stage valve 62 is controlled by an electric motor 76.

[0056] In the second implementation scheme, such as Figure 8 As shown, separate inter-valve connections 78 and 79 exist between the isolation valve 60 and the stage valve 62; the first inter-valve connection 78 connects the isolation valve 60 to the main injection fuel conduit 80 of the stage valve, and the second inter-valve connection 79 connects the isolation valve 60 to the pre-injection fuel conduit 82 of the stage valve 62. As shown, these isolation functions are shared within the same isolation valve 60, but it can still provide the pre-injection and main injection isolation functions that are located in separate valves, for example... Figure 10 As shown in the image.

[0057] In an alternative version of the second implementation scheme, such as Figure 9 As shown, the pre-injection and main injection isolation valves are electronically controlled by separate solenoids 84 and 86. The two solenoids 84 and 86 are electrically isolated from each other. The control system can be arranged such that the main injection solenoid 86 can only open when the pre-injection solenoid 84 is open, ensuring that fuel flows to the first intervalve connection 78 only when fuel also flows to the pre-injection fuel conduit 82 in the stage valve 62. In this configuration, when the pre-injection solenoid 84 is powered, fuel can flow down through the second intervalve connection 79 in the stage valve 62 to the pre-injection fuel conduit 82. When both the pre-injection solenoid 84 and the main injection solenoid 86 are powered, fuel can also flow down through the first intervalve connection 78 to the main injection fuel conduit 80 in the stage valve 62. The isolation valve 60 may include separate pre-injection spring 88 and main injection spring 90, which push the pre-injection solenoid 84 and the main injection solenoid 86, thereby improving the definition of the valve's intermediate position, i.e., when fuel is supplied only to the pre-injection fuel injector 64. The pre-injection spring 88 of the pre-injection solenoid can be relatively weak, similar to known hydraulic mechanical weight distribution valves, where the force is equivalent to a few psi of fuel pressure. The main injection spring 90 of the main injection solenoid 86 can be relatively strong, comparable to those used in known fuel distribution valves, where the force is equivalent to a fuel pressure between 20 psi and 200 psi. Alternatively, a single spring providing different force ranges against the solenoids 84 and 86 can be used.

[0058] Figure 10 A third embodiment is shown, in which the isolation valves are divided into a separate main injection isolation valve 92 and a pre-injection isolation valve 94. Isolation valves 92 and 94 are arranged in series such that the inlet flow for the main injection isolation valve 92 originates from a branch of the outlet flow for the pre-injection isolation valve 94. This arrangement is characterized in that fuel flows to the first inter-valve connection 78 only after it has first flowed to the second inter-valve connection 79. Actuation of valves 92, 94, and 92 can originate from the same control manifold 70 as shown, or from separate first control manifold 70, second control manifold 72, and third control manifold 73, as shown. Figure 11 As shown, this is consistent with all other aspects. Figure 10 Same. If the same control manifold 70 is used, the opening pressures of the two isolation valves 92 and 94 can be selected, so that the pre-injection isolation valve 94 opens at a lower control pressure than the main injection isolation valve 92.

[0059] In equivalent design (see...) Figure 13 ), can be done through something similar to Figure 9Electronic devices are used to control the isolation valve. The pre-injection solenoid 84 and the main injection solenoid 86 can be arranged in series with a fluid connection, such that fuel reaches the first isolation valve 94 before being diverted between the fuel flow at the connection between the second intervalve connection 79 and the main injection isolation valve 92, where the main injection isolation valve only controls the fuel flow to the main injection fuel conduit 80 within the stage valve 62. In this design, if the pre-injection solenoid 84 is deactivated (i.e., kept open), the main injection solenoid 86 can be used to restrict fuel flow to the main injection fuel injector 66, regardless of the stage valve setting. This provides additional redundancy in some failure scenarios. The profile of the pre-injection fuel conduit 82 within the stage valve 62 prevents excessive fuel flow to the pre-injection fuel injector 64 in this state.

[0060] The separation of the main injection isolation valve 92 from the pre-injection isolation valve 94 and the stage valve 62 also allows the main injection flow isolation valve 92 to open before the main injection fuel conduit 80 opens at the stage valve 62. Doing so during operation of the pre-injection fuel injector only allows the first intervalve connection 78 to be filled with fuel before the main injection conduit 80 of the stage valve 62 is opened, thus reducing the amount of time required to supply fuel to the main injection fuel injector 66 when engine acceleration is required. Go-around and terrain warning are specific conditions where this function may be most useful.

[0061] In the fourth implementation scheme, such as Figure 12 As shown, isolation valve 60 and stage valve 62 are connected to valve control module 96. Through... Figure 9 Compared to the arrangement shown, this arrangement has the advantage of reducing the total amount of wiring required to control the two valves 60, 62, thereby reducing weight and cost. In this example, the bridge rectifier function 96 is shown. The bridge rectifier rectifies the three motor control lines 98 to provide DC solenoid drive, thus eliminating the need for individual drives in the control unit. It should be understood that any suitable type of valve control module can be used in this system.

[0062] It should be understood that the two control methods—pressure and electronic—are not mutually exclusive, and it is also possible to combine the valve control types described herein in a single burner head 54. For example, control manifolds 70, 73 can be used to pressure control the opening and closing of isolation valves 60, 94 in any of the aforementioned burner heads, and an electric motor can be used to control staged valve 62, such as... Figure 14 As shown. Similarly, control manifold 72 can be used to control the stage valve 62 of any of the aforementioned burner heads, and an electric motor or solenoid can be used to control isolation valves 60, 94, examples of which are shown in Figure 15 As shown in the image.

[0063] It should be understood that this disclosure is not limited to the above-described embodiments, and various modifications and improvements may be made without departing from the concepts described herein and within the scope of the claims below.

Claims

1. A burner head for a fuel manifold, the burner head comprising: Main injection fuel injector; Pre-injection fuel injector; Fuel source; A first isolation valve is connected to the fuel source; and A grading valve, the grading valve being connected to the first isolation valve, and the grading valve having a main injection fuel conduit connected to the main injection fuel injector and a pre-injection fuel conduit connected to the pre-injection fuel injector; and The second isolation valve is connected in series between the first isolation valve and the main injection fuel conduit of the staged valve, but is not connected to the pre-injection fuel conduit. The first isolation valve and the stage valve are connected in series, such that fuel from the fuel source must pass through the first isolation valve before reaching the stage valve, and the force required to open the first isolation valve is different from the force required to open the second isolation valve.

2. The burner head according to claim 1, wherein the first isolation valve is controlled by a solenoid and the staged valve is controlled by an electric motor.

3. The burner head according to claim 2, wherein the second isolation valve is controlled by a solenoid.

4. The burner head according to claim 3, wherein the burner head further comprises a valve control module, the valve control module being connected to the first isolation valve, the second isolation valve, and the staged valve.

5. The burner head according to claim 1, wherein the first isolation valve and the staged valve are pressure valves.

6. The burner head according to claim 1, wherein the second isolation valve is a pressure valve.

7. The burner head according to claim 1, wherein the force required to open the first isolation valve is less than the force required to open the second isolation valve.

8. The burner head of claim 7, wherein a single spring is used to provide different forces to the first isolation valve and the second isolation valve.

9. The burner head according to claim 1, wherein the first isolation valve is connected to a first control flow source, and the staged valve is connected to a second control flow source.

10. The burner head of claim 1, wherein the second isolation valve is connected to a third control flow source.

11. The burner head according to claim 1, wherein at least one of the first isolation valve, the second isolation valve and the stage valve is an electronic valve, and wherein at least one of the first isolation valve, the second isolation valve and the stage valve is a pressure valve.

12. A fuel manifold for a gas turbine engine, the fuel manifold comprising one or more combustor heads according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11.

13. A gas turbine engine comprising a fuel manifold including one or more combustor heads according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or 11.

Images