Fuel nozzle with reduced flow tolerance

Abstract

A fuel nozzle metering valve includes a valve core having an inlet port and an outlet flow port, and a retainer assembled to one end of the valve core. A valve liner accommodates a portion of the valve core. The valve core is configured to move back and forth within the valve liner. The metering valve is biased in a closed position in which the outlet flow port is completely disposed within the valve liner. The valve opens when the valve core slides within the valve liner so that some portion of the outlet flow port extends beyond the end of the valve liner. The retainer has a stepped portion configured to abut an end of the retainer at a fuel flow pressure that is lower than an expected maximum fuel flow pressure to be used in the fuel nozzle metering valve.

Description

Technical Field

[0001] The present invention generally relates to fuel nozzles for jet engines. Background Art

[0002] Gas turbines for jet engines typically contain fuel nozzles that are arranged in a circumferentially uniform manner around the axis of the engine, through which the fuel is introduced into the combustion chamber. In addition, fuel nozzles with a "wide" flow range can be equipped with flow metering valves to optimize low flow rate and high flow rate injection quality. The fuel is regulated through valve ports, which are designed to meet the fuel flow rate required by the customer. Flow path geometry variations and valve displacement non-uniformity (hysteresis) cause flow variations in each fuel nozzle. The valve is usually spring-loaded and is actuated as the fuel flow pressure increases, it initially opens, and then displaces in response to higher pressure values. Valve displacement is usually unimpeded over the entire range of applied fuel flow pressures.

[0003] Jet engine operation generally requires that the fuel nozzle has a minimum nozzle flow tolerance, especially at higher engine power settings. The embodiments of the invention described below provide a fuel nozzle that improves upon the prior art in terms of minimum flow tolerance. These and other advantages of the invention and additional inventive features will become apparent from the description provided herein. Summary of the invention

[0004] In one aspect, an embodiment of the present invention provides a fuel nozzle metering valve, comprising a valve core having an inlet port and an outlet flow port, and a retainer assembled to one end of the valve core. A valve liner that accommodates a portion of the valve core. The valve core is configured to move back and forth within the valve liner. The metering valve is biased in a closed position, in which the outlet flow port is completely disposed within the valve liner. The valve opens when the valve core slides within the valve liner so that some portion of the outlet flow port extends beyond the end of the valve liner. The retainer has a stepped portion that is configured to abut the end of the valve liner at a fuel flow pressure that is lower than an expected maximum fuel flow pressure to be used in the fuel nozzle metering valve.

[0005] In certain embodiments, the valve core is configured to slide out of the valve liner when the fuel flow pressure from the fuel flowing into the inlet port overcomes the closing bias on the metering valve. The retaining member can be disc-shaped, and in certain embodiments, the stepped portion extends from the central region of the disc-shaped retaining member. The stepped portion can be cylindrical or partially cylindrical.

[0006] In some embodiments, the valve liner is fixed within the fuel nozzle, and wherein the valve core and retainer move relative to the valve liner. In another embodiment, the metering valve is biased in a closed position by a spring. The spring may include a first end abutting a flange of the retainer and may have a second end abutting a flange of the valve liner.

[0007] In another aspect, an embodiment of the present invention provides a fuel nozzle check valve, comprising a valve core and a valve liner having an inlet port, and a retainer assembled to one end of the valve core. The valve liner accommodates a portion of the valve core. The valve core is configured to move back and forth within the valve liner. The valve liner includes a valve liner port, which is fluidically connected to an outlet flow port on the valve liner when the check valve is in an open position. The check valve is biased in a closed position, wherein the outlet flow port is completely disposed within the valve liner. When the valve core slides within the valve liner, the valve opens so that some portion of the outlet flow port is opened to allow flow through. The retainer has a stepped portion, which is configured to abut an end of the valve liner at a fuel flow pressure lower than the expected maximum fuel flow pressure to be used in the fuel nozzle check valve.

[0008] In certain embodiments, the valve core is configured to slide out of the valve liner when fuel flow pressure from the fuel flowing into the inlet port overcomes the closing bias on the check valve. The retainer may be disc-shaped, and in certain embodiments, the stepped portion extends from a central region of the disc-shaped retainer. The stepped portion may be cylindrical or partially cylindrical.

[0009] In some embodiments, the valve liner is fixed within the fuel nozzle, and wherein the valve core and retainer move relative to the valve liner. In other embodiments, the check valve is biased in a closed position by a spring. In a particular embodiment, the spring has a first end abutting a flange of the retainer and a second end abutting a flange of the valve liner.

[0010] Other aspects, objectives and advantages of the present invention will become more apparent from the following detailed description in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the present invention. In the drawings:

[0012] Figure 1 is a cross-sectional view of a fuel nozzle metering valve having a flow restriction feature constructed in accordance with an embodiment of the present invention;

[0013] Figure 2is a cross-sectional view of a fuel nozzle check valve having a flow restriction feature constructed in accordance with an embodiment of the present invention; and

[0014] Figure 3 is a graph showing an exemplary flow profile for an embodiment of the fuel nozzle of the present disclosure.

[0015] While the invention will be described in conjunction with certain preferred embodiments, it is not intended to be limited to those embodiments. On the contrary, the intention is to cover all alternatives, modifications and equivalents included within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION

[0016] For any given flow device operating at set conditions, the flow rate through the device is proportional to the square root of the pressure differential across the device. The flow rate is also proportional to the flow path area of ​​the device. Therefore, any change in the flow path area will result in a change in flow rate for any set condition. Therefore, conventional jet engine fuel nozzles with integrated flow metering valves or check valves tend to introduce additional flow path changes and corresponding flow rate changes due to the dynamic characteristics of each valve in each fuel nozzle within the jet engine.

[0017] As described below, embodiments of the present invention provide improved flow tolerance for any fuel nozzle equipped with a check valve or metering valve, especially at high flow rates where the durability and reliability of the combustion chamber and turbine are very sensitive to flow non-uniformity. One of ordinary skill in the art will be able to recognize from the illustrated embodiments that the valve flow port design configuration and limit the maximum valve displacement that can occur before the maximum pressure ensure that a fixed flow circuit geometry is achieved at all pressure points greater than the maximum displacement. In this case, the valve spring characteristics, valve port geometry, and valve clearance effects become fixed features within the fuel nozzle. This acts to limit flow rate variations and reduce flow tolerance.

[0018] Figure 1 is a cross-sectional view of a fuel nozzle metering valve 100 having a flow restriction feature constructed in accordance with an embodiment of the present invention. The metering valve 100 has a spring-loaded poppet or valve core 102 having one or more flow control ports 104 that moves back and forth within a sleeve or valve liner 106 in response to fuel flow pressure. The valve liner 106 is fixed within the fuel nozzle. A spring retainer 108 is assembled to one end of the valve core 102 so that when the valve core 102 moves within the valve liner 106, the spring retainer 108 moves with the valve core 102. The spring retainer 108 is machined to limit valve core displacement at a specific flow rate and fuel flow pressure. When the fuel nozzle metering valve 100 operates as described, the spring-loaded valve core 102 and the spring retainer 108 operate to accurately set the valve flow at a fixed geometry.

[0019] In operation, when the valve 100 is in the open position, fuel flows into the metering valve 100 via the inlet port 112 and exits the metering valve 100 through the one or more flow control ports 104. When the fuel flow pressure is relatively low, the metering valve 100 is biased in the closed position. Although various means for biasing the metering valve 100 may be used, Figure 1 The biasing means is shown as a spring 110 which closes the valve 100 so that no fuel flows through the metering valve 100. One end of the spring 110 abuts against a valve liner flange 122, while the other end of the spring 110 abuts against a spring retainer flange 124. Figure 1 In the embodiment of the present invention, when one or more flow control ports 104 are located inside the valve liner 106, fuel does not flow. When the bias causes the valve core 102 to disengage from the valve liner 106, leakage flow occurs even if one or more flow control ports 104 are still inside the valve liner 106. However, when the pressure of the fuel from the fuel flowing into the inlet port 112 increases, the flow control port 104 begins to slide out of the valve liner 106. As the flow control port 104 extends beyond the second end 116 of the valve liner 106, fuel can flow out of the metering valve 100.

[0020] As the fuel flow pressure increases, the step 118 machined into the spring retainer 108 abuts the first end 114 of the valve liner 106 and serves as a flow restriction feature. The step 118 portion of the spring retainer 108 extends toward the first end 114 of the valve liner 106. In a particular embodiment, the spring retainer 108 is disc-shaped, and the step 118 extends from the center portion of the disc toward the first end 114. The step 118 can be cylindrical or partially cylindrical. After a certain amount of spool displacement due to the fuel flow pressure, long before the maximum fuel flow pressure is reached, the spring retainer 108 is designed so that the step 118 abuts the first end 114. Therefore, for certain portions of the fuel flow pressure, the flow geometry of the metering valve 100 is fixed. As a result, the fuel flow rate through the metering valve 100 is more predictable than in a conventional fuel nozzle with a conventional metering valve.

[0021] Figure 1 The illustrated gap 120 shows the maximum valve core displacement. On one side of the gap 120, the first end of the valve liner 106 constrains the valve core 102 in the open position. On the other side of the gap 120, the valve core displacement is limited by the maximum bias of the valve core 102 adjacent the inner portion of the first end 114 or by the maximum bias applied by the spring 110. The step 118 is sized to provide a specific fuel flow profile for each individual fuel nozzle.

[0022] Figure 2 FIG. 2 is a cross-sectional view of a fuel nozzle check valve 200 having a flow restriction feature constructed according to an embodiment of the present invention. The check valve 200 has a Figure 1 A similar arrangement is shown in FIG. 1 for limiting the displacement of the valve plug of a check valve assembly. In this configuration, one or more outlet flow ports 204 are incorporated into the valve liner 206, but the basic concept is the same as Figure 1 The metering valve 100 is the same.

[0023] The valve core 202 moves back and forth in the valve liner 206 in response to the fuel flow pressure. The position of the valve liner 206 is fixed in the fuel nozzle. A spring retainer 208 is assembled to one end of the valve core 202 so that when the valve core 202 moves in the valve liner 206, the spring retainer 208 moves with the valve core 202. The spring retainer 208 is processed to limit the displacement of the valve core at a specific flow rate and fuel flow pressure. Figure 1 In the embodiment of FIG. 1 , when operating the fuel nozzle check valve 200 , the spring loaded spool 202 and the spring retainer 208 operate to accurately set the valve flow at a fixed geometry that is less than a maximum expected fuel pressure.

[0024] In operation, the downstream diameter of the valve core 202 extends beyond the one or more outlet flow ports 204. When the valve is in the open position, fuel flows into the check valve 200 via the inlet port 212 and exits the check valve 200 through the one or more outlet flow ports 204. When the fuel flow pressure is relatively low, the check valve 200 is biased in the closed position. When the check valve 200 is in the closed position because the one or more outlet flow ports 204 are blocked by the valve core 202, fuel does not flow. Although various means for biasing the check valve 200 may be used, Figure 2 The biasing means is shown as a spring 210 which closes the valve 200 so that no fuel flows through the check valve 100. One end of the spring 210 abuts a valve liner flange 222, while the other end of the spring 210 abuts a spring retainer flange 224.

[0025] When the pressure of the fuel flowing into the inlet port 212 is sufficient to overcome the closing bias of the spring 210, the valve core 202 begins to slide out of the valve liner 206, while the spring retainer 208 is pulled toward the first end 214 of the valve liner 206. As the one or more outlet flow ports 204 extend beyond the second end 216 of the valve liner 206, fuel can flow out of the check valve 200. Figure 2 In the embodiment of the present invention, one or more outlet flow ports 204 are disposed on a peripheral portion of an end portion of the valve liner 206. The end portion of the valve liner includes four protrusions 226, which are arranged in a cylindrical shape and have four equidistant gaps 228, which separate the four protrusions 226. When the valve core 202 slides out of the valve liner 206 a sufficient distance, fuel can flow out from the one or more outlet flow ports 204 where the gaps 228 are located.

[0026] As fuel flow pressure increases, a step 218 machined into the spring retainer 208 abuts the first end 214 of the valve liner 206 and acts as a flow restriction feature. The step 218 portion of the spring retainer 208 extends toward the first end 214 of the valve liner 206.

[0027] In a particular embodiment, the spring retainer 208 is disc-shaped, and the step 218 extends from a central portion of the disc toward the first end 214. The step 218 may be cylindrical or partially cylindrical. After a certain amount of spool displacement due to fuel flow pressure, well before the maximum fuel flow pressure is reached, the spring retainer 208 is designed so that the step 218 abuts the first end 214. Thus, for certain portions of the fuel flow pressure, the flow geometry of the check valve 200 is fixed, making the fuel flow rate through the check valve 200 more predictable than in a conventional fuel nozzle having a conventional check valve.

[0028] and Figure 1 Same, Figure 2 The illustrated gap 220 shows the maximum valve core displacement. On one side of the gap 220, the first end of the valve liner 206 constrains the valve core 202 in the open position. On the other side of the gap 220, the valve core displacement is limited by the maximum bias at the inner portion of the valve core 202 adjacent to the first end 214 or by the maximum bias applied by the spring 210. The step 218 is sized to provide a specific fuel flow profile for each individual fuel nozzle.

[0029] The fuel flow tolerance of a nozzle constructed according to an embodiment of the present invention was tested against the tolerance specification requirements for such a fuel nozzle. The average minimum-maximum flow variation of the 20 tested fuel nozzle assemblies constructed according to an embodiment of the present invention was 42% less than the nominal specification requirement at the highest inlet pressure. The average minimum-maximum flow variation of the group of twenty nozzle assemblies over the operating pressure range is shown in Figure 3 . The graph shows the percentage flow variation associated with the inlet pressure. The upper curve 250 depicts the flow variation specification for a typical fuel nozzle. The lower curve 252 shows the average flow variation of 20 fuel nozzles constructed according to the embodiment described in the present invention.

[0030] As described above, the fuel nozzle flow tolerance is reduced, such as Figure 3 As shown, this is achieved using a fixed valve geometry at higher flow rates. Limiting valve displacement until the maximum inlet pressure is reached is how the fuel nozzle valve works to achieve this fixed geometry. The maximum valve displacement for each assembly is set to the target flow and pressure, thereby achieving repeatable flow rates that would otherwise rely on the compounding effects of component geometry variations.

[0031] All references, including publications, patent applications, and patents cited herein, are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0032] In describing the present invention (especially in describing the following claims), the terms "a", "one (a and an)" and "said" and similar terms used should be interpreted as including the singular and the plural, unless otherwise specified in the text or clearly contradicted by the text. The terms "including", "having", "including" and "containing" should be interpreted as open terms (i.e., meaning "including but not limited to"), unless otherwise specified. Unless otherwise specified in this article, the enumeration of numerical ranges herein is intended only to be used as a shorthand method of individually citing each individual value falling within the range, and each individual value is incorporated into the specification as if it were individually listed in this article. All methods described herein can be performed in any suitable order, unless otherwise specified in the text or clearly contradicted by the text. Any and all examples, or example language (such as "for example") used herein are only used to better illustrate the present invention and do not limit the scope of the present invention, unless otherwise stated. Any language in the specification should not be interpreted as indicating that any unclaimed element is essential to the practice of the present invention.

[0033] Preferred embodiments of the present invention are described herein, including the best mode known to the inventor for implementing the present invention. Variations of those preferred embodiments will become apparent to those of ordinary skill in the art after reading the above description. The inventor expects that such variations will be appropriately adopted by those skilled in the art, and the inventor intends to practice the present invention in a manner different from that specifically described herein. Therefore, the present invention includes all modifications and equivalent forms of the subject matter recorded in the appended claims where permitted by applicable law. In addition, unless otherwise specified herein or clearly contradictory to the context, the present invention includes any combination of all possible variations of the above elements.

Claims

1. A fuel nozzle metering valve, comprising: a valve core having an inlet port and a flow control port; an integral retainer assembled to one end of the valve core, the integral retainer having a stepped portion extending from a central region thereof, the stepped portion having an axial length configured to limit valve core displacement at a specific flow rate and fuel flow pressure to accurately set a valve flow rate in a fixed geometric state; a valve liner that receives a portion of the valve core, wherein the valve core is configured to move back and forth within the valve liner; wherein the metering valve is biased in a closed position in which the flow control port is completely disposed within the valve liner, wherein when the valve core slides out of the valve liner, the metering valve opens such that portions of the flow control port extend beyond an end of the valve liner, and the stepped portion is configured to abut an end of the valve liner at a fuel flow pressure that is lower than an expected maximum fuel flow pressure to be used in the fuel nozzle metering valve; and A buffer is formed in the valve liner between an end portion of the valve liner adjacent to the stepped portion of the retainer and a flange formed on an outer surface of the valve core.

2. The fuel nozzle metering valve according to claim 1, wherein: The valve spool is configured to slide out of the valve liner when fuel flow pressure from fuel flowing into the inlet port overcomes the closing bias on the metering valve.

3. The fuel nozzle metering valve according to claim 1, wherein: The integrated retainer is disc-shaped, and the stepped portion extends from a central region of the integrated disc-shaped retainer.

4. The fuel nozzle metering valve according to claim 1, wherein: The stepped portion is cylindrical or partially cylindrical.

5. The fuel nozzle metering valve according to claim 1, wherein: The valve liner is fixed within the fuel nozzle, and wherein the valve core and retainer move relative to the valve liner.

6. The fuel nozzle metering valve according to claim 1, wherein: The metering valve is spring biased in a closed position.

7. The fuel nozzle metering valve according to claim 6, wherein: The spring has a first end abutting the flange of the retainer and a second end abutting the flange of the valve liner.

8. A fuel nozzle check valve, comprising: a valve liner having an inlet port and an outlet flow port; A valve core is disposed in the valve liner; a retainer assembled to one end of the valve core, the retainer having a stepped portion extending from a central region thereof, the stepped portion having an axial length configured to limit the displacement of the valve core at a specific flow rate and fuel flow pressure to accurately set the valve flow rate in a fixed geometric state; wherein the valve liner receives a portion of the valve core, the valve core being configured to move back and forth within the valve liner, wherein the valve liner includes a valve liner port that is in fluid communication with the outlet flow port when the check valve is in an open position; and wherein the check valve is biased in a closed position in which the outlet flow port is blocked when the valve plug is fully disposed within the valve liner, wherein the check valve opens when the valve plug slides out of the valve liner so that the outlet flow port is not blocked by the valve plug, and the stepped portion of the retainer is configured to abut an end of the valve liner at a fuel flow pressure that is lower than an expected maximum fuel flow pressure to be used in the fuel nozzle check valve; and A buffer is formed in the valve liner between an end portion of the valve liner adjacent to the stepped portion of the retainer and a flange formed on an outer surface of the valve core.

9. The fuel nozzle check valve according to claim 8, wherein: The valve spool is configured to slide out of the valve liner when fuel flow pressure from fuel flowing into the inlet port overcomes the closing bias on the check valve.

10. The fuel nozzle check valve according to claim 8, wherein: The holder is disc-shaped, and the stepped portion extends from a central region of the disc-shaped holder.

11. The fuel nozzle check valve according to claim 8, wherein: The stepped portion is cylindrical or partially cylindrical.

12. The fuel nozzle check valve according to claim 8, wherein: The valve liner is fixed within the fuel nozzle, and wherein the valve core and retainer move relative to the valve liner.

13. The fuel nozzle check valve according to claim 8, wherein: The check valve is spring biased in a closed position.

14. The fuel nozzle check valve according to claim 13, wherein: The spring has a first end abutting a flange of the retainer and a second end abutting a flange of the valve liner.

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