Bearing rotor thrust control

Abstract

A rotor thrust balancing system for a turbine and a method of using the same are generally disclosed. For example, a rotor thrust balancing system for a turbine, wherein the turbine defines a centerline extending the length of the turbine. The system includes a rotary drive shaft, a thrust bearing, and a first waveguide sensor. The rotary drive shaft connects the turbine section and the compressor section of the turbine. The thrust bearing supports the rotary drive shaft of the turbine. The thrust bearing includes multiple ball bearings, an inner race connected to the rotary drive shaft, and an outer race connected to a fixed structure. The first waveguide sensor is connected to the outer race at a first end. The waveguide sensor transmits the vibration frequency from the thrust bearing to a second end of the waveguide sensor.

Description

[0001] Federal government-funded research

[0002] This invention was completed with government support under Air Force contract number FA8650-15-D-2501. The government may enjoy certain rights to this invention. Technical Field

[0003] This topic generally relates to turbines, and more specifically, to the balancing thrust bearing system in turbines. Background Technology

[0004] A gas turbine engine generally comprises a fan and a core arranged in fluid communication with each other. Furthermore, the core of the gas turbine engine generally comprises a compressor section, a combustion section, a turbine section, and an exhaust section arranged in a series sequence. In operation, air is supplied from the fan to the inlet of the compressor section, where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are then directed from the combustion section to the turbine section. The flow of combustion gases through the turbine section drives the turbine section and is subsequently directed through the exhaust section to, for example, the atmosphere.

[0005] Conventional gas turbine engines include a rotor assembly with a shaft, compressor impeller, turbine, coupling, sealing assembly, and other components for optimal operation under given operating conditions. These rotor assemblies have a constant static mass due to gravity and also generate power due to imbalances in the rotor assembly during operation, acceleration, etc. In addition to radial axial forces, the rotating assembly experiences axial forces generated by, for example, internal pressures between turbine stages and thrust from the gas turbine engine. Such gas turbine engines include radial and thrust bearings to withstand and support these forces while allowing the rotor assembly to rotate. For example, the sum of axial forces can result in a net axial force or thrust. This thrust can be in a forward or rearward direction. Thrust bearings can be used to absorb this thrust and allow the rotor assembly to continue rotating.

[0006] In some cases, the net axial force or thrust acting on a thrust bearing can shift its direction from forward to rearward, or vice versa; this is known as cross-over. Therefore, without compensation, cross-over can result in unloaded ball bearings in the thrust bearing. Unloaded ball bearings reduce the radial centering of the rotor, leading to altered seal clearances. Low rotor thrust on the bearing can also cause the ball bearing to slip relative to the raceway, potentially leading to slippage damage. Furthermore, low rotor thrust reduces effective bearing stiffness, which can adversely affect rotor dynamics.

[0007] To prevent cross-propagation, some rotor assemblies are designed so that the combined thrust remains unidirectional, forward, or backward, across a wide range of operating conditions. To compensate for unidirectional turbine assemblies, such designs can result in extremely large and heavy bearings. For example, thrust bearings must be able to support thrust loads while being limited to receiving net forward or backward forces.

[0008] Therefore, lighter and smaller thrust bearings will be useful in systems capable of correcting thrust crossover. More specifically, rotor thrust systems that can utilize both the forward and backward capabilities of thrust bearings while reducing size and weight will be particularly advantageous. Summary of the Invention

[0009] The aspects and advantages will be set forth in part in the following description, or may be apparent from the description, or may be learned by practice of the invention.

[0010] In one aspect, this disclosure relates to a rotor thrust balancing system for a turbine, wherein the turbine defines a centerline extending the length of the turbine. The system includes a rotary drive shaft, a thrust bearing, and a first waveguide sensor. The rotary drive shaft connects a turbine section and a compressor section of the turbine. The thrust bearing supports the rotary drive shaft of the turbine. The thrust bearing includes a plurality of ball bearings, an inner race coupled to the rotary drive shaft, and an outer race coupled to a fixed structure. The first waveguide sensor is coupled to the outer race at a first end of the waveguide sensor. The waveguide sensor transmits a vibration frequency from the thrust bearing to a second end of the waveguide sensor.

[0011] In one embodiment, the system further includes a second waveguide sensor. A first end of the first waveguide sensor is connectable to a front end of the outer race relative to the centerline. A first end of the second waveguide sensor is connectable to a rear end of the outer race relative to the centerline. In another embodiment, the system further includes a thrust chamber in contact with a rotary drive shaft. The thrust chamber can be pressurized to change the force on the rotary drive shaft forward or backward relative to the centerline. In different embodiments, the thrust chamber is located in the turbine section of the turbine. In yet another embodiment, the thrust chamber is located in the compressor section of the turbine.

[0012] In another embodiment, the first waveguide sensor includes a second end located outside the turbine. In yet another embodiment, the system further includes a control sensor located at the second end of the first waveguide sensor. The control sensor can transmit the vibration frequency of the thrust bearing to the turbine's control system. In one exemplary embodiment, the control system is in communication with a valve to decrease or increase the pressure supplied to the thrust chamber. Thus, the thrust chamber can change the force on the rotating drive shaft forward or backward relative to the centerline. In another embodiment, the control sensor is a piezoelectric sensor. In yet another embodiment, the control system is a full-authority engine control system.

[0013] In one exemplary embodiment, the rotary drive shaft is a high-pressure drive shaft that connects the high-pressure turbine section to the high-pressure compressor section. In another embodiment, the rotary drive shaft is a low-pressure drive shaft that connects the low-pressure turbine section to at least one of the low-pressure compressor section or the fan section.

[0014] In another aspect, this disclosure relates to a method for balancing rotor thrust on a thrust bearing of a turbine. The turbine defines a centerline extending the length of the turbine. The method includes transmitting an vibration frequency from the thrust bearing to the outside of the turbine using a waveguide sensor coupled to the thrust bearing. In another step, the method includes transmitting the vibration frequency to a control sensor communicatively coupled to a control system. In a different step, the method includes determining whether the thrust bearing is in a crossed state. In yet another step, the method includes changing the force on a rotating drive shaft to disengage the thrust bearing from the crossed state.

[0015] In one embodiment, the vibration frequency includes the ball passing frequency. In another embodiment, the method includes determining whether the ball passing frequency of the thrust bearing is below a first threshold. In an exemplary embodiment, the method further includes changing the pressure of the thrust chamber in contact with the rotary drive shaft in response to the cross-state of the thrust bearing. In yet another embodiment, the method includes transmitting a signal from a control system to a valve. The valve may be coupled to and receive pressurized fluid from the compressor section of the turbine, and selectively deliver the pressurized fluid to the thrust chamber in contact with the rotary drive shaft. In one embodiment, the method further includes changing the pressure of the thrust chamber. Thus, the changed pressure of the thrust chamber can change the force applied to the rotary drive shaft.

[0016] In another aspect, the present invention relates to a method for determining the direction of rotor thrust on a thrust bearing of a turbine, wherein the turbine defines a centerline extending the length of the turbine. The method includes transmitting a ball-passing frequency from the thrust bearing to the outside of the turbine using a first waveguide sensor and a second waveguide sensor coupled to the thrust bearing. The method further includes transmitting the ball-passing frequency to a control sensor communicatively coupled to a control system. In another step, the method includes comparing the magnitude of a first ball-passing frequency transmitted from a first waveguide sensor at a front end of the thrust bearing relative to the centerline with the magnitude of a second ball-passing frequency transmitted from a second waveguide sensor at a rear end of the thrust bearing relative to the centerline.

[0017] In an exemplary embodiment, the method further includes determining the direction of the rotor thrust acting on the rotary drive shaft relative to the centerline based on the difference between the amplitude of the first ball passing frequency and the second ball passing frequency.

[0018] Technical Solution 1. A rotor thrust balancing system for a turbine, wherein the turbine defines a centerline extending the length of the turbine, the system comprising:

[0019] A rotary drive shaft connects the turbine section and the compressor section of the turbine;

[0020] A thrust bearing that supports the rotary drive shaft of the turbine; the thrust bearing comprises:

[0021] Multiple ball bearings;

[0022] Inner race, which is connected to the rotary drive shaft; and

[0023] The outer race, which is connected to the fixed structure; and

[0024] A first waveguide sensor is connected to the outer race at a first end of the waveguide sensor, wherein the waveguide sensor transmits the vibration frequency from the thrust bearing to a second end of the waveguide sensor.

[0025] Technical Solution 2. The system according to Technical Solution 1, characterized in that the system further includes:

[0026] The second waveguide sensor, wherein the first end of the first waveguide sensor is connected to the front end of the outer race relative to the center line, and the first end of the second waveguide sensor is connected to the rear end of the outer race relative to the center line.

[0027] Technical Solution 3. The system according to Technical Solution 1, characterized in that the system further includes:

[0028] A thrust chamber that contacts the rotary drive shaft, wherein the thrust chamber is pressurized to change the force on the rotary drive shaft forward or backward relative to the centerline.

[0029] Technical Solution 4. The system according to Technical Solution 3, characterized in that the thrust chamber is located in the turbine section of the turbine.

[0030] Technical Solution 5. The system according to Technical Solution 3, characterized in that the thrust chamber is located in the compressor section of the turbine.

[0031] Technical Solution 6. The system according to Technical Solution 1, characterized in that the first waveguide sensor includes a second end located outside the turbine.

[0032] Technical Solution 7. The system according to Technical Solution 6, characterized in that the system further includes:

[0033] A control sensor, located at the second end of the first waveguide sensor, is used to transmit the vibration frequency of the thrust bearing to the control system of the turbine.

[0034] Technical Solution 8. The system according to Technical Solution 7, characterized in that the control system communicates with the valve to reduce or increase the pressure supplied to the thrust chamber, and wherein the thrust chamber changes the force on the rotary drive shaft forward or backward relative to the centerline.

[0035] Technical Solution 9. The system according to Technical Solution 7, wherein the control sensor is a piezoelectric sensor.

[0036] Technical Solution 10. The system according to Technical Solution 7, characterized in that the control system is a full authority engine control system.

[0037] Technical Solution 11. The system according to Technical Solution 1, characterized in that the rotary drive shaft is a high-pressure drive shaft that connects the high-pressure turbine section to the high-pressure compressor section.

[0038] Technical Solution 12. The system according to Technical Solution 1, characterized in that the rotary drive shaft is a low-pressure drive shaft that connects the low-pressure turbine section to at least one of the low-pressure compressor section or the fan section.

[0039] Technical Solution 13. A method for balancing rotor thrust on a thrust bearing of a turbine, wherein the turbine defines a centerline extending the length of the turbine, the method comprising:

[0040] A waveguide sensor connected to the thrust bearing is used to transmit the vibration frequency from the thrust bearing to the outside of the turbine;

[0041] The vibration frequency is transmitted to a control sensor that is communicatively coupled to the control system.

[0042] Determine whether the thrust bearing is in a crossed state; and

[0043] Change the force on the rotary drive shaft to disengage the thrust bearing from the crossed state.

[0044] Technical Solution 14. The method according to Technical Solution 13, wherein the vibration frequency includes the ball passing frequency.

[0045] Technical Solution 15. The method according to Technical Solution 14, characterized in that the method further includes:

[0046] Determine whether the frequency of the balls passing through the thrust bearing is lower than a first threshold.

[0047] Technical Solution 16. The method according to Technical Solution 13, characterized in that the method further includes:

[0048] The pressure in the thrust chamber that is in contact with the rotary drive shaft changes in response to the cross-state of the thrust bearing.

[0049] Technical Solution 17. The method according to Technical Solution 13, characterized in that the method further includes:

[0050] The signal is transmitted from the control system to a valve, which is connected to and receives pressurized fluid from the compressor section of the turbine, and selectively delivers the pressurized fluid to a thrust chamber in contact with the rotary drive shaft.

[0051] Technical Solution 18. The method according to Technical Solution 17, characterized in that the method further includes:

[0052] The pressure in the thrust chamber is changed, wherein the changed pressure in the thrust chamber alters the force applied to the rotary drive shaft.

[0053] Technical Solution 19. A method for determining the direction of rotor thrust on a thrust bearing of a turbine, wherein the turbine defines a centerline extending the length of the turbine, the method comprising:

[0054] The ball bearing pass frequency is transmitted from the thrust bearing to the outside of the turbine using a first waveguide sensor and a second waveguide sensor connected to the thrust bearing.

[0055] The ball bearings are transmitted via frequency to a control sensor coupled to the control system via communication; and

[0056] The amplitude of the frequency at which the first ball passes through, transmitted from the first waveguide sensor at the front end of the thrust bearing relative to the centerline, is compared with the amplitude of the frequency at which the second ball passes through, transmitted from the second waveguide sensor at the rear end of the thrust bearing relative to the centerline.

[0057] Technical Solution 20. The method according to Technical Solution 19, characterized in that the method further includes:

[0058] The direction of the rotor thrust acting on the rotary drive shaft relative to the centerline is determined based on the difference between the amplitude of the first ball passing frequency and the second ball passing frequency.

[0059] These and other features, aspects, and advantages will become more readily understood with reference to the following description and the appended claims. The accompanying drawings, incorporated in and constituting a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. Attached Figure Description

[0060] The invention, including its best mode, is fully and adequately disclosed in the description with reference to the accompanying drawings, which are intended to enlighten those skilled in the art.

[0061] Figure 1 A cross-sectional view of one embodiment of a gas turbine engine that can be used in an aircraft according to aspects of this subject matter;

[0062] Figure 2 A cross-sectional view of one embodiment of a thrust bearing housing sealing system for a shaft seal bearing housing relative to a gas turbine engine, according to aspects of this subject matter;

[0063] Figure 3 For aspects of this topic Figure 2 The image shows a close-up cross-sectional view of the bearing housing sealing system, with particular emphasis on the sealing housing housing and waveguide sensor attached to the thrust bearing;

[0064] Figure 4 A view of a system for balancing rotor thrust on a thrust bearing, based on aspects of this topic;

[0065] Figure 5 In order to be based on aspects of this topic Figure 4 A schematic diagram of the thrust chamber used in the system, which is located in the turbine section of the turbine.

[0066] Figure 6 In order to be based on aspects of this topic Figure 4 A schematic diagram of the thrust chamber used in the system, located at the compressor exhaust pressure seal of the turbine;

[0067] Figure 7 In accordance with the aspects of this topic Figure 4 A schematic diagram of the two thrust chambers used in the system, one of which is located in front of the thrust bearing and the other is located behind the thrust bearing;

[0068] Figure 8 A schematic diagram of a thrust chamber defined by two rotating structures according to aspects of this topic;

[0069] Figure 9 A flowchart illustrating a method for using a system for balancing rotor thrust on a thrust bearing, based on aspects of this subject matter; and

[0070] Figure 10 A flowchart illustrating another method for using a system for balancing rotor thrust on a thrust bearing, based on aspects of this subject matter.

[0071] The repeated use of reference numerals in this specification and the accompanying drawings is intended to indicate the same or similar features or elements of the invention.

[0072] Parts list

[0073] 10 Gas Turbine Engine

[0074] 12 Longitudinal / Axial Centerline

[0075] 14-core turbocharged engine

[0076] 16-fan section

[0077] 18 tubular shells

[0078] 20 Circular Entrances

[0079] 22 booster compressor

[0080] 23 Compressor Section

[0081] 24 High-Pressure Compressor

[0082] 26 burners

[0083] 28 First / High Pressure Turbine

[0084] 29 Turbine Section

[0085] 30 First / High Pressure Drive Shaft

[0086] 31 Rotary Drive Shaft

[0087] 32 Second / Low-Pressure Turbine

[0088] 33 High-pressure shaft

[0089] 34 Second / Low-Pressure Drive Shaft

[0090] 35 Low-pressure shaft

[0091] 36 exhaust nozzles

[0092] 37. Reduction Gear

[0093] 38 Rotatable / Axial Flow Fan Rotor Assembly

[0094] 39 outer surface

[0095] 40 ring fan housing

[0096] 42 outlet guide vanes

[0097] 44 fan rotor blades

[0098] 46 Downstream Section

[0099] 48 Bypass airflow duct

[0100] Arrow 50 (entering airflow at 10)

[0101] 52 entrances

[0102] Arrow 54 (First compressed air flow)

[0103] Arrow 56 (Second compressed air flow)

[0104] Arrow 58 (entering the airflow at 24)

[0105] 60 High-energy combustion products

[0106] 100 Bearing Housing Sealing System

[0107] 102 Thrust Bearing Housing

[0108] 104 Labyrinth Seal

[0109] 106 carbon seals

[0110] 112 stator guide vanes

[0111] 114 catheters

[0112] 116 turbine blades

[0113] 118 thrust bearing

[0114] 119 radial bearing

[0115] 120 tanks or chambers

[0116] 124 High-Pressure Chamber

[0117] 126 vent port

[0118] 128 inner seat ring

[0119] 130 outer seat ring

[0120] 132 ball bearing

[0121] 136 inner surface

[0122] 138 outer surface

[0123] 140 groove

[0124] 142 outer side

[0125] 144 inner side

[0126] 146 hairpin-shaped components

[0127] 162 outer shaft section

[0128] 164 inner shaft section

[0129] 166 radial wall

[0130] 168 chambers

[0131] 200 rotor thrust balancing system

[0132] 201 First Waveguide Sensor

[0133] 202 waveguide sensor

[0134] 203 Second Waveguide Sensor

[0135] 204 (of 201) first end

[0136] 205 (of 203) first end

[0137] 206 (201) second end

[0138] 207 (203) second end

[0139] 208 piezoelectric sensor

[0140] 209 front end

[0141] 210 Full Authority Digital Engine Control (FADEC) System

[0142] 211 rear end

[0143] 212 communication cable

[0144] 214 communication cable

[0145] 216 valve

[0146] 218 First Pipeline

[0147] 220 Second Pipeline

[0148] 222 thrust chamber

[0149] 223 First Thrust Chamber

[0150] 224 Fixed Structure

[0151] 225 Second Thrust Chamber

[0152] 226 Rotary Structure

[0153] 227 First Rotational Structure

[0154] 228 Thrust Chamber Seal

[0155] 229 Compressor Discharge Pressure (CDP) Seals

[0156] 230 Second Rotation Structure

[0157] 300 methods

[0158] 302 Method Steps

[0159] 304 Method and Steps

[0160] 306 Method Steps

[0161] 308 Method Steps

[0162] 310 Method Steps

[0163] 312 Method Steps

[0164] 314 Method and Steps

[0165] 400 methods

[0166] 402 Method Steps

[0167] 404 troubleshooting steps. Detailed Implementation

[0168] Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The various examples are provided by way of illustrative purposes rather than limiting the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, it is intended that the invention cover such modifications and variations falling within the scope of the appended claims and their equivalents.

[0169] As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of an independent component.

[0170] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid channel. For example, "upstream" refers to the direction from which the fluid flows, while "downstream" refers to the direction to which the fluid flows.

[0171] Generally, a system for balancing the rotor thrust of a turbine and a method for achieving this balancing are provided. In one embodiment, the system includes a rotary drive shaft, a thrust bearing, and a first waveguide sensor. The rotary drive shaft generally connects the turbine section and the compressor section of the turbine. In one embodiment, the thrust bearing includes a plurality of ball bearings, an inner race, and an outer race, such that the inner race is coupled to the rotary drive shaft and the outer race is coupled to a stationary structure. According to a particular embodiment, the first waveguide sensor is coupled to the outer race at a first end of the waveguide sensor. Generally, the waveguide sensor can transmit vibration frequencies from the thrust bearing to a second end of the waveguide sensor.

[0172] In some embodiments, the rotor thrust balancing system for turbines prevents the thrust bearing from operating in a crossed state. Avoiding this crossed state reduces the occurrence of unloaded ball bearings in the thrust bearing. For example, preventing crossed states allows for better radial centering of the rotor and proper sealing clearance. Preventing ball bearing slippage relative to the raceway prevents slippage damage. Furthermore, preventing low rotor thrust helps ensure proper effective bearing stiffness and avoids adverse effects on rotor dynamics.

[0173] In some embodiments, the ability to measure and correct for rotor thrust crossover will allow the product engine to have a wider range of rotor thrust without increasing the total amplitude of rotor thrust in any one direction. Furthermore, lower amplitude bearing thrust loads allow for smaller, lighter bearings. For example, bearing size can be minimized by concentrating rotor thrust near zero or near the zero point while still avoiding crossover, thus allowing for a smaller amplitude thrust load. Additionally, using waveguide sensors instead of measurement techniques (such as accelerometers) allows the sensor to be attached to the bearing where the accelerometer may not have sufficient reliability. For example, the least reliable portion of the waveguide sensor (e.g., a piezoelectric sensor) can be mounted externally to the engine, where this portion is subjected to less heat and is easier to replace.

[0174] It should be recognized that although this subject matter will be described generally with reference to gas turbine engines, the disclosed systems and methods can be used generally on thrust bearings within any suitable type of turbine engine, including aircraft-based turbine engines, land-based turbine engines, and / or steam turbine engines. Furthermore, although this subject matter is described generally with reference to high-pressure shafts of turbine engines, it should also be recognized that the disclosed systems and methods can be used on any shaft within a turbine engine (e.g., low-pressure or intermediate-pressure shafts).

[0175] Now refer to the attached diagram, Figure 1A cross-sectional view of one embodiment of a gas turbine engine 10 for use in an aircraft according to aspects of this subject matter is shown, wherein the engine 10 shown has a longitudinal or axial central axis 12 extending through it for reference purposes. Generally, the engine 10 may include a core gas turbine engine (generally indicated by reference numeral 14) and a fan section 16 positioned upstream therefrom. The core engine 14 may generally include a generally tubular housing 18 defining an annular inlet 20. Furthermore, the housing 18 may further enclose and support a compressor section 23. For the embodiment shown, the compressor section 23 includes a booster compressor 22 and a high-pressure compressor 24. The booster compressor 22 generally increases the pressure of the air entering the core engine 14 (indicated by arrow 54) to a first pressure level. The high-pressure compressor 24 (such as a multi-stage axial compressor) may then receive pressurized air from the booster compressor 22 (indicated by arrow 58) and further increase the pressure of this air. The pressurized air leaving the high-pressure compressor 24 can then flow to the burner 26, where fuel is injected into the pressurized air stream, and the resulting mixture is burned within the burner 26.

[0176] In the illustrated embodiment, housing 18 may further enclose and support turbine section 29. Furthermore, in the depicted embodiment, turbine section 29 includes a first high-pressure turbine 28 and a second low-pressure turbine 32. In the illustrated embodiment, high-energy combustion products 60 are directed from combustor 26 along the hot gas path of engine 10 to high-pressure turbine 28 for driving high-pressure compressor 24 via first high-pressure drive shaft 30. Subsequently, combustion products 60 may be directed to low-pressure turbine 32 for driving supercharger compressor 22 and fan section 16 via a second low-pressure drive shaft 34, which is generally coaxial with the first drive shaft 30. After each of the drive turbines 28 and 32, combustion products 60 may be discharged from core engine 14 via exhaust nozzle 36 to provide propulsive jet thrust.

[0177] In addition, such as Figure 1 As shown, the fan section 16 of engine 10 may generally include a rotatable axial fan rotor assembly 38 enclosed by an annular fan housing 40. Those skilled in the art will recognize that the fan housing 40 may be supported relative to the core engine 14 by a plurality of generally radially extending, circumferentially spaced outlet guide vanes 42. Thus, the fan housing 40 may enclose the fan rotor assembly 38 and its corresponding fan blades 44. Furthermore, a downstream section 46 of the fan housing 40 may extend over an external portion of the core engine 14 to define a secondary or bypass airflow duct 48, thereby providing additional propulsive thrust.

[0178] It should be recognized that, in several embodiments, the low-pressure drive shaft 34 may be directly coupled to the fan rotor assembly 38 to provide a direct drive configuration. Alternatively, the low-pressure drive shaft 34 may be coupled to the fan rotor assembly 38 via a reduction gear 37 (e.g., a reduction gear, gearbox, or transmission) to provide an indirect drive or gear-driven configuration. Such reduction gears(s) 37 may also be located between any other suitable shafts and / or shafts within the engine, as desired or required.

[0179] During operation of engine 10, it should be understood that an initial airflow (indicated by arrow 50) enters engine 10 through the relevant inlet 52 of fan housing 40. In the illustrated embodiment, airflow 50 then passes through fan blades 44 and splits into a first compressed airflow (indicated by arrow 54) moving through duct 48 and a second compressed airflow (indicated by arrow 56) entering supercharger compressor 22. In the depicted embodiment, the pressure of the second compressed airflow 56 subsequently increases and enters high-pressure compressor 24 (as indicated by arrow 58). After mixing with fuel and burning within combustor 26, combustion products 60 exit combustor 26 and flow through high-pressure turbine 28. Thereafter, in the illustrated embodiment, combustion products 60 flow through low-pressure turbine 32 and exit exhaust nozzle 36 to provide thrust to engine 10.

[0180] In some embodiments, engine 10 may be an adaptive cycle engine or a variable cycle engine. The performance of gas turbine engine 10 can be balanced between energy efficiency and high thrust generation by designing the bypass ratio between airflow duct 48 and the core gas turbine engine 14. The bypass ratio can be defined by the ratio of a first compressed air flow 54 moving through airflow duct 48 to a second compressed air flow 56 moving through the core gas turbine engine 14. Generally, a gas turbine engine 10 with a high bypass ratio corresponds to a highly efficient gas turbine engine 10, but the gas turbine engine 10 may have a relatively low maximum thrust. Similarly, a gas turbine engine 10 with a low bypass ratio may have a higher maximum thrust, but the gas turbine engine 10 may have lower efficiency.

[0181] An adaptive cycle engine or a variable cycle engine can incorporate a variable bypass ratio design. For example, when high thrust is required, such as during takeoff, the bypass ratio can be adjusted to a lower value. Similarly, when high efficiency is desired, such as during cruise, the bypass ratio can be adjusted to a higher value. The bypass ratio can be adjusted by changing the area of ​​the airflow duct 48 and the inlet of the core gas turbine engine 14. In another embodiment, additional ducting can be used to selectively deliver more or less air to the core gas turbine engine 14 or the airflow duct 48.

[0182] Generally refer to Figure 3-7According to aspects of this subject matter, examples for turbines (such as, but not limited to) are shown. Figure 1 Various views of embodiments of a rotor thrust balancing system 200 for a gas turbine engine 10). For reference purposes, the turbine defines a centerline 12 extending the length of the turbine. In the illustrated embodiment, the system 200 includes a rotary drive shaft 31, a thrust bearing 118, and a first waveguide sensor 201. In the illustrated embodiment, the rotary drive shaft 31 connects the turbine section 29 and the compressor section 23 of the turbine. The thrust bearing 118 may include a plurality of ball bearings 132, an inner race 128, and an outer race 130. In the depicted embodiment, the inner race 128 is coupled to the rotary drive shaft 31, and the outer race 130 is coupled to a fixed structure, such as a thrust bearing housing 102. In an exemplary embodiment, the first waveguide sensor 201 is coupled to the outer race 130 at a first end 204 of the first waveguide sensor 201. Furthermore, the first waveguide sensor 201 can transmit vibration frequencies from the thrust bearing 118 to a second end 206 of the first waveguide sensor 201.

[0183] Again, specifically refer to Figure 1 System 200 generally includes a rotary drive shaft 31 that connects the turbine section 29 and the compressor section 23 of the turbine. In one embodiment, the rotary drive shaft 31 is a high-pressure drive shaft 30 that connects a high-pressure turbine 28 to a high-pressure compressor 24. The high-pressure turbine 28, the high-pressure compressor 24, and the high-pressure drive shaft 30 may be collectively referred to as the high-pressure shaft 33. In another embodiment, the rotary drive shaft 31 is a low-pressure drive shaft 34 that connects a low-pressure turbine 32 to a low-pressure compressor (such as a booster compressor 22) and a fan section 16. Alternatively, the low-pressure drive shaft 34 may connect the low-pressure turbine 32 only to the booster compressor 22 or only to the fan section 16. The low-pressure turbine 32, the low-pressure drive shaft 34, and at least one of the booster compressor 22 or the fan section 16 may be collectively referred to as the low-pressure shaft 35. In yet another embodiment (not shown), the rotary drive shaft 31 may be an intermediate-pressure drive shaft that connects an intermediate compressor to an intermediate turbine. The intermediate-pressure drive shaft, intermediate-pressure compressor, and intermediate-pressure turbine can be collectively referred to as the intermediate-pressure rotor.

[0184] It should be recognized that, in other embodiments, the invention may include any combination of a low-pressure drive shaft 34, a high-pressure drive shaft 30, and a medium-pressure drive shaft. For example, both the high-pressure drive shaft 30 and the low-pressure drive shaft 34 may be coupled to the thrust bearing 118 and the waveguide sensor 202, as described in more detail below.

[0185] Now refer to Figure 2-3 The diagram illustrates an embodiment of a bearing housing sealing system 100 including a thrust bearing 118, according to aspects of this subject matter. Specifically, Figure 2A cross-sectional view of a sealing system 100 for suppressing lubrication of the thrust bearing housing 102 relative to the rotating drive shaft 31 of the gas turbine engine 10. Figure 3 for Figure 2 The close-up cross-sectional view of the sealing system 100 shown in the figure particularly shows the labyrinth seal 104 and the carbon seal 106 (such as a hydrodynamic seal), which are disposed at opposite axial ends of the bearing housing 102.

[0186] like Figure 2 As shown, the sealing system 100 can substantially isolate the bearing housing 102 from the high-pressure drive shaft 30, which rotates relative to it. However, the sealing system 100 can isolate any stationary components and any rotating shafts (e.g., the low-pressure drive shaft 34) of the engine 100. In the illustrated embodiment, relative rotation occurs as one or more stator guide vanes 112 guide the flow of combustion products 60 through ducts 114 to one or more turbine blades 116 coupled to the high-pressure drive shaft 30. The thrust bearing 118 supports the high-pressure drive shaft 30 relative to various stationary components in the engine 10. Furthermore, in the illustrated embodiment, the bearing housing 102 at least partially encloses the thrust bearing 118 radially, thereby forming a groove or chamber 120, preferably having a radial shape, in which the thrust bearing 118 is disposed. Lubricant (e.g., oil) for lubricating the various components of the thrust bearing 118 can circulate within the chamber 120. In the illustrated embodiment, a high-pressure chamber 124 is located outside the bearing housing 102. In an exemplary embodiment, vent flow from compressor section 23, turbine section 29 and / or fan section 16 passes through vent port 126 to pressurize high pressure chamber 124 to a pressure relatively greater than the pressure in chamber 120.

[0187] In the illustrated embodiment, at least two seals (such as labyrinth seal 104 and carbon seal 106) separate the high-pressure drive shaft 30 from the bearing housing 102. However, the at least two seals can be any suitable type of seal. For example, in other embodiments, multiple laboratory seals, carbon seals, and / or hydrodynamic seals may be used in the sealing system 100. In the illustrated embodiment, labyrinth seal 104 and carbon seal 106 separate the high-pressure chamber 124 from the bearing housing 120. Figure 2 A labyrinth seal 104 is shown positioned upstream of the carbon seal 106; however, the carbon seal 106 may also be positioned downstream of the labyrinth seal 104.

[0188] In this respect, for the illustrated embodiment, the bearing housing 102, at least two seals (e.g., labyrinth seal 104 and carbon seal 106), and the high-pressure drive shaft 30 collectively enclose the chamber 120. That is, the combination of the bearing housing 102, at least two seals, and the high-pressure drive shaft 30 can completely enclose the chamber 120 axially, radially, and circumferentially. Furthermore, for the illustrated embodiment, at least two seals (e.g., labyrinth seal 104 and carbon seal 106) are the only seals enclosing the chamber 120; however, it should be recognized that in other embodiments, any number of seals may be used to enclose the chamber 120, such as three or more.

[0189] exist Figure 3 The embodiment shown depicts a close-up view of a thrust bearing 118 and a bearing housing 102. For example, the bearing 118 includes an inner race 128 extending circumferentially around an outer surface 39 of a high-pressure drive shaft 30. In the illustrated embodiment, an outer race 130 is disposed radially outward from the inner race 128 and mates with a fixed structure (such as the inner surface of the bearing housing 102). The inner race 128 and the outer race 130 may have separate race configurations. In the depicted embodiment, the inner race 128 and the outer race 130 clamp at least one ball bearing 132 therebetween. Preferably, the inner race 128 and the outer race 130 clamp at least three ball bearings 132 therebetween. In other embodiments, the inner race 128 and the outer race 130 may clamp at least one cylinder between them to form the thrust bearing 118.

[0190] Figure 3 The labyrinth seal 104 and carbon seal 106 are shown in more detail. In the illustrated embodiment, the labyrinth seal 104 and carbon seal 106 (such as hydrodynamic seals) are non-contact seals, which do not require contact between stationary and moving components during high-speed operation. Non-contact seals typically have a longer service life than contact seals. However, in other embodiments, one or both seals may be contact seals. Various types of seals can operate in different ways. In the illustrated embodiment, the labyrinth seal 104 includes an inner surface 136 and an outer surface 138. For example, a tortuous path (not shown) extending between the inner surface 136 and the outer surface 138 prevents lubricant from escaping from the bearing housing 102. In the illustrated exemplary embodiment, the air pressure on the outer side 138 of the labyrinth seal 104 (i.e., in the high-pressure chamber 124) is greater than the air pressure on the inner side 136 of the labyrinth seal 104 (i.e., in the chamber 120). In this respect, stationary and rotating components can be separated by an air membrane during their relative rotation.

[0191] However, in the illustrated embodiment, the carbon seal 106 (such as a hydrodynamic seal) includes one or more recesses 140 that separate the stationary member and the rotating member. The air pressure on the outer side 142 of the carbon seal 106 (i.e., in the high-pressure chamber 124) may be greater than the air pressure on the inner side 144 of the carbon seal 106 (i.e., in the chamber 120). Therefore, in the illustrated embodiment, airflow from the high-pressure chamber 124 passes through the recesses 140 into the chamber 120, thereby creating an air film between the stationary member and the rotating member. Additionally, in other embodiments, the carbon seal 106 may be a contact-type carbon seal.

[0192] In one embodiment, the carbon seal 106 approaches and seals against the hairpin-shaped member 146 of the high-pressure drive shaft 30. For example, the hairpin-shaped member 146 includes a radially outer shaft portion 162 that is radially offset relative to a radially inner shaft portion 164 by a radial wall 166. In this respect, for the illustrated embodiment, the radially outer shaft portion 162, the radially inner shaft portion 164, and the radial wall 166 define a cavity 168 therebetween. In one embodiment, the radially outer shaft portion 162 seals against the carbon seal 106. In this respect, the radially outer shaft portion 162 may contact the carbon seal 106 when the high-pressure drive shaft 30 is stationary or rotating at a low speed. However, for the illustrated embodiment, the carbon seal 106 disengages from the radially outer shaft portion 162 when the high-pressure drive shaft 30 rotates at a high speed.

[0193] In the illustrated embodiment, the hairpin-shaped component 146 can improve the performance of the gas turbine engine 10. For example, lubricant from chamber 120 can contact and cool the radially inner side of the radially outer shaft portion 162 of the hairpin-shaped component 146. In the illustrated embodiment, this cools the radially outer side of the radially outer shaft portion 162, which contacts the carbon seal 106 at low speeds and approaches the carbon seal 106 at high speeds. That is, heat from the radially outer side can be conducted through the radially outer shaft portion 162 to its radially inner side, which is cooled by the lubricant. This keeps the carbon seal 106 cooler, which in turn allows the gas turbine engine 10 to operate hotter and faster, thereby improving its performance for the illustrated embodiment.

[0194] For the illustrated embodiment, the pressure on the outer side 138 of the labyrinth seal 104 and the outer side 142 of the carbon seal 106 should be substantially the same. That is, the air pressure in the high-pressure chamber 124 should always be substantially the same to prevent the generation of airflows. These airflows can guide air away from the carbon seal 106.

[0195] Now refer to Figure 4The diagram illustrates a view of a rotor thrust balancing system 200 for a turbine, according to an aspect of this subject matter. For the illustrated embodiment, system 200 includes at least one waveguide sensor 202 (such as a first waveguide sensor 201) coupled at first ends 204, 205 of the waveguide sensor 202 to the outer race 130 of a thrust bearing 118. It should be appreciated that the inner race 128 can be coupled to any rotary drive shaft 31. For example, the rotary drive shaft 31 can be a high-pressure drive shaft 30. In another embodiment, the rotary drive shaft 31 can be a low-pressure drive shaft 34.

[0196] It should be recognized that, in other embodiments, the waveguide sensor 202 may be coupled to the bearing housing 102. For example... Figure 4 As shown in the embodiment, waveguide sensor 202 transmits the vibration frequency from thrust bearing 118 to the second ends 206, 207 of waveguide sensor 202. As used herein, the terms “communicating,” “communication,” “communication,” “communicates,” “communicationally,” and the preceding variations mean direct communication or indirect communication, such as through a memory system or another intermediate system.

[0197] The vibration frequency transmitted from the waveguide sensor 202 can be used to assess the health of any bearing. For example, a broken or worn ball bearing 132 can alter the frequency of the thrust bearing 118. Therefore, a change in frequency transmitted by the waveguide sensor 202 can indicate that the ball bearing 132 requires maintenance or replacement. Furthermore, a change in the frequency of the thrust bearing 118 can also indicate damage or defects in the inner race 128 or the outer race 130. Thus, in some embodiments, the system 200 can be used to monitor the health of bearings, such as the health of the thrust bearing 118.

[0198] The waveguide sensor 202 described herein may include a structure that guides waves along a path while reducing energy loss. For example, a waveguide reduces energy loss or signal attenuation by limiting its extension along one or two dimensions. In an embodiment of the disclosed system 200, the waveguide sensor 202 transmits vibrations or acoustic waves along the length of the waveguide sensor 202 from a first end 204, 205 to a second end 206, 207. For example, the waveguide sensor 202 may be a metal wire extending the length of the waveguide sensor 202, which is at least partially enclosed within a sheath. The metal wire may be directly mounted to the bearing of interest, such as thrust bearing 118 or bearing housing 102. In the depicted embodiment, the waveguide sensor 202 is mounted on both the front end 209 and the rear end 211 of the thrust bearing 118. Thus, the waveguide sensor 202 can sense low rotor thrust and determine the direction of loading on the thrust bearing 118, as described in more detail below.

[0199] Furthermore, the waveguide sensor 202 allows the measuring device to receive signals originating from the first ends 204, 205 at the second ends 206, 207. More specifically, for the illustrated embodiment, the waveguide sensor 202 transmits vibration signals from the thrust bearing 118 to the exterior of the engine 10, the exterior of the core gas turbine engine 14, or both. Therefore, the second ends 206, 207 of the waveguide sensor 202 can be located outside the engine 10, outside the core gas turbine engine 14, or both.

[0200] In some embodiments, system 200 includes a control sensor at the second ends 206, 207 of waveguide sensor 202. Still referring to... Figure 4 The control sensor may be a piezoelectric sensor 208. The piezoelectric sensor 208 described herein may include means for determining them by converting changes in pressure, acceleration, temperature, strain, or force into electrical charge using the piezoelectric effect. For example, it is known that the piezoelectric sensor 208 produces a change in voltage when deformed under stress. Therefore, some piezoelectric sensors 208 produce readable voltage or current fluctuations when exposed to vibration, such as the vibration frequency transmitted to the second ends 206, 207 of the waveguide sensor 202 and subsequently to the piezoelectric sensor 208.

[0201] Now refer to Figure 3-4 In the illustrated embodiment, system 200 may include a first waveguide sensor 201 and a second waveguide sensor 203. More specifically, a first end 204 of the first waveguide sensor 201 may be coupled to the outer race 130 at a front end 209 relative to the centerline 12. Similarly, a first end 205 of the second waveguide sensor 203 may be coupled to the outer race 130 at a rear end 211 relative to the centerline 12. It should be appreciated that in other embodiments, system 200 may include only one waveguide sensor 202, or may include three or more waveguide sensors 202.

[0202] Furthermore, the vibration frequency transmitted by the waveguide sensor 202 can be any frequency associated with the bearing. For example, the transmitted vibration frequency can be the ball pass frequency. In the depicted embodiment, the ball pass frequency can be the rate at which the ball bearing 132 passes a specific position on one of the races 128, 130. The term ball pass frequency can generally refer to the ball pass frequency on the inner race 128 or the ball pass frequency on the outer race 130. The ball pass frequency can be predicted analytically based on the geometry of the thrust bearing 118 and the rotor speed. For example, the curvature of the races 128, 130, the internal radial clearance between the inner race 128 and the outer race 130, and the number of ball bearings 132 can be used to predict the ball pass frequency.

[0203] In the illustrated embodiment, waveguide sensor 202 is coupled to outer race 130. Therefore, the ball pass frequency transmitted by waveguide sensor 202 can be the outer ball pass frequency. In the crossover state, no forward or backward force is applied to the bearing. This condition can result in a slipping rather than smooth rotation of the unloaded ball bearing 132. For example, ball bearing 132 may slip on inner race 128 instead of rotating. Therefore, the ball pass frequency on outer race 130 can decrease, indicating bearing slippage and thus a crossover state on thrust bearing 118. For example, the ball pass frequency can decrease to approximately five to ten percent below the predicted value, indicating bearing slippage. Furthermore, the ball pass frequency can decrease to approximately zero, indicating that the bearing is in a near-complete slippage state.

[0204] Now, specifically refer to Figure 4 System 200 may include a control system communicatively linked to a control sensor (e.g., piezoelectric sensor 208) located at the second ends 206, 207 of waveguide sensor 202. For example, a first waveguide sensor 201 may have a second end 206. Similarly, a second waveguide sensor 203 may have a second end 207. Thus, vibration frequencies (such as ball-pass frequencies) can be transmitted to the control system. For example, system 200 may include a Full Authority Digital Engine Control (FADEC) system 210 that communicates with piezoelectric sensor 208 via communication cable 212. In the illustrated embodiment, piezoelectric sensor 208 transmits the ball-pass frequency of thrust bearing 118 to FADEC 210 of engine 10.

[0205] In the illustrated embodiment, once the ball pass frequency is transmitted to the control system, the control system determines whether the thrust bearing 118 is in a crossed state. For example, the FADEC 210 may receive a signal from the piezoelectric sensor 208 via the communication cable 212 and determine whether the ball pass frequency is below a first threshold. In an exemplary embodiment, a ball pass frequency below the first threshold may correspond to a thrust bearing 118 in a crossed state.

[0206] Furthermore, system 200 can be used to determine and monitor the direction of rotor thrust using two waveguide sensors 201, 203. For example, FADEC 210 can receive signals from piezoelectric sensor 208 coupled to waveguide sensors 201, 203. Thus, for the illustrated embodiment, FADEC 210 receives the ball-pass frequencies at both the front end 209 and the rear end 211 of the outer race 130. Although the ball-pass frequencies at the two locations can be the same, the amplitudes of the ball-pass frequencies can be different. For example, a forward-acting rotor thrust can produce a higher amplitude ball-pass frequency at the front end 209 of the outer race 130. Conversely, a backward-acting rotor thrust can produce a higher amplitude ball-pass frequency at the rear end 211 of the outer race 130. Therefore, for the illustrated embodiment, FADEC 210 compares the amplitude of the ball passing frequency at both the front end 209 and the rear end 211 of the outer race 130 and determines the direction of the rotor thrust acting on the thrust bearing 118 and the high-pressure drive shaft 30.

[0207] Now, in general, refer to Figure 4-7 And specifically refer to Figure 4 System 200 can alter the force acting on the high-pressure drive shaft 30 to disengage the thrust bearing 118 from its crossed state. For example, system 200 may include a thrust chamber 222 in contact with the high-pressure drive shaft 30. In the depicted embodiment, altered pressure in the thrust chamber 222 causes the high-pressure drive shaft 30 to move forward or backward relative to the centerline 12 of the engine 10. For example, the thrust chamber 222 may be defined by a fixed structure 224, a rotating structure 226, and at least one thrust chamber seal 228. The thrust chamber seal 228 may be any seal known in the art, such as, but not limited to, labyrinth seals, hydrodynamic seals, or carbon seal 106. For example, altered pressure in the thrust chamber 222 may change the force exerted by the thrust chamber 222 on the rotating structure 226. It should be appreciated that, in the depicted embodiment, the high-pressure drive shaft 30 includes the rotating structure 226. For example, the rotating structure 226 may be coupled to the high-pressure drive shaft 30 or may be formed as a single piece with the high-pressure drive shaft 30. Therefore, in the illustrated embodiment, the force applied to the rotating structure 226 of the high-pressure drive shaft 30 is transmitted to the thrust bearing 118 to push it forward or backward away from the cross state.

[0208] It should also be recognized that the gas engine 10 may include one or more radial bearings 119 positioned between the rotary drive shaft 31 or the rotating structure 226 and the stationary structure 224. The radial bearings 119 may support the rotary drive shaft 31 generally by a radial force perpendicular to the centerline 12.

[0209] Furthermore, the control system (such as FADEC 210) can send a signal in response to a cross-state in the thrust bearing 118 to pressurize the thrust chamber 222. For example, FADEC 210 can transmit a signal to valve 216 via communication cable 214 to increase or decrease the pressure supplied to the thrust chamber 222. In the illustrated embodiment, valve 216 is coupled to the high-pressure compressor 24 and receives pressurized fluid, such as air, via a first line 218. Additionally, in the illustrated embodiment, valve 216 is coupled to the thrust chamber 222 via a second line 220. Thus, in the illustrated embodiment, a signal from FADEC 210 causes valve 216 to selectively open, allowing venting to pressurize the thrust chamber 222 via the second line 220. It should be appreciated that the pressurized fluid can originate from any source, such as, but not limited to, the booster compressor 22, the high-pressure turbine 28, the low-pressure turbine 32, or a pump. Furthermore, the thrust chamber 222 can be used to remove the thrust bearing 118 from the crossed state by venting from the thrust chamber 222, thereby reducing the force applied to the high-pressure drive shaft 30.

[0210] In one embodiment, FADEC 210 is a closed-loop control system. For example, the initial setpoint or range can be selected based on the difference between the ball pass frequency at the front end 209 and the ball pass frequency at the rear end 211 of the outer race 130. This difference can represent the thrust bearing 118 loaded with the desired thrust load in a forward or backward direction. In one embodiment, FADEC 210 can compare the actual difference between the ball pass frequency and the setpoint, and calculate an adjustment representing the difference between the setpoint and the actual difference. Furthermore, FADEC 210 can subsequently use this adjustment as input to change the force applied to the rotating structure 226 by the thrust chamber 222. Thus, the closed-loop control system can maintain the thrust bearing 118 at a desired setpoint or range.

[0211] Now, specifically refer to Figure 5A schematic diagram of one embodiment of a thrust chamber 222 located in the turbine section 29 of engine 10 is shown according to an aspect of this subject matter. As shown, in the illustrated embodiment, the thrust chamber 222 is defined by a fixed structure 224, a rotating structure 226, and two thrust chamber seals 228. In an exemplary embodiment, the thrust chamber 222 can vary the force on the rotating drive shaft 31 forward or backward relative to the centerline 12. For example, an increased pressure supplied to the thrust chamber 222 increases the pressure on the rotating structure 226 and can apply a force to the rotating drive shaft 31 (e.g., high-pressure drive shaft 30) in a rearward direction. Similarly, in the illustrated embodiment, a decreased pressure supplied to the thrust chamber 222 decreases the pressure on the rotating structure 226 and can allow a net force on the high-pressure drive shaft 30 to move the high-pressure drive shaft 30 in a forward direction. It should be appreciated that, in the exemplary embodiment, the increase or decrease in pressure can be used to change the force acting on the high-pressure drive shaft 30 and disengage the thrust bearing 118 from its crossed state. It should be recognized that, in other embodiments, the thrust chamber 222 may be located in the compressor section 23, and the rotary drive shaft 31 may be a low-pressure drive shaft 34.

[0212] Now, specifically refer to Figure 6 This diagram illustrates one embodiment of a thrust chamber 222 located downstream of the high-pressure compressor section 24, according to an aspect of this subject matter. In the illustrated embodiment, a thrust chamber seal 228 is defined at least partially by a compressor discharge pressure (CDP) seal 229. For example, the CDP seal 229 can be any type of seal known in the art, such as, but not limited to, a labyrinth seal 104. In the illustrated embodiment, the thrust chamber 222 is pressurized by allowing air to leak from the high-pressure compressor section 24 through a vent port 126. For example, pressurized air from the vent port 126 can pressurize the thrust chamber 222 through the CDP seal 229. In the illustrated embodiment, the thrust chamber 222 is defined by the thrust seal 228, a stationary structure 224, and a rotating structure 226. Therefore, the force applied to the high-pressure drive shaft 30 can be varied by changing the pressure in the thrust chamber 222 to supply more or less pressure to the rotating structure 226. More specifically, in the illustrated embodiment, more or less air may be released from the high-pressure compressor section 24.

[0213] It should be recognized that, in another embodiment, the force acting on the rotating structure 226 can be varied by changing the volume of the thrust cavity 222. More specifically, increasing the volume of the thrust cavity 222 increases the surface area of ​​the rotating structure 226. Therefore, the pressure in the thrust cavity 222 can act on a larger surface area and generate a larger force on the high-pressure drive shaft 30. Similarly, decreasing the volume of the thrust cavity 222 decreases the surface area of ​​the rotating structure 226. Therefore, the pressure in the thrust cavity 222 can act on a smaller surface area and generate a smaller force on the high-pressure drive shaft 30.

[0214] Now refer to Figure 7 According to aspects of this disclosure, an embodiment of a system 200 for balancing rotor thrust using two thrust chambers 222 is shown. For example, system 200 may include a first thrust chamber 223 located in front of thrust bearing 118, such as at or near high-pressure compressor 24. Furthermore, for the illustrated embodiment, system 200 includes a second thrust chamber 225 located behind thrust bearing 118, such as at or near high-pressure turbine 28. As shown, the pressure in the first thrust chamber 223 may be increased to apply a forward force to rotating structure 226 and high-pressure drive shaft 30. Similarly, the pressure in the second thrust chamber 225 may be increased to apply a rearward force to rotating structure 226 and high-pressure drive shaft 30. Thus, system 200 can remove thrust bearing 118 from a crossed state by applying forces forward or backward to rotating drive shaft 31 (such as high-pressure drive shaft 30) via correspondingly increasing the pressure in the first thrust chamber 223 or second thrust chamber 225. Furthermore, Figure 7 Waveguide sensor 202 is shown outside the engine 10, extending into the control system.

[0215] It should be recognized that system 200 can use any thrust cavity 222 in contact with the rotary drive shaft 31 to balance the rotor thrust on the thrust bearing 118. For example, any sealed cavity in contact with the rotary drive shaft 31 or a rotating structure 226 coupled to the rotary drive shaft 31 can be pressurized to supply force axially to the rotary drive shaft 31. Furthermore, the system can be used to balance rotor thrust on the low-pressure drive shaft 34 or the medium-pressure drive shaft.

[0216] Now refer to Figure 8This illustration shows a schematic diagram of one embodiment of a thrust chamber 222 located in turbine section 29 and including two rotating structures 226, according to aspects of this subject matter. As shown, for the illustrated embodiment, the thrust chamber 222 is defined by a first rotating structure 227 coupled to a high-pressure drive shaft 30, a second rotating structure 230 coupled to a low-pressure drive shaft 34, and a plurality of thrust chamber seals. In an exemplary embodiment, the increased pressure supplied to the thrust chamber 222 increases the pressure on the rotating structures 227, 230. For example, the increased pressure can exert a forward force on the first rotating structure 227, and thus a forward force on the high-pressure drive shaft 30. Similarly, for the illustrated embodiment, the increased pressure can exert a rearward force on the second rotating structure 230, and thus a rearward force on the low-pressure drive shaft 34. Therefore, for the illustrated embodiment, the thrust chamber 222 allows for joint adjustment of the high-pressure drive shaft 30 and the low-pressure drive shaft 34.

[0217] It should be understood that, for the illustrated embodiment, the reduced pressure can be supplied with reduced force on both the first rotating structure 227 and the second rotating structure 230. For example, the reduced pressure supplied to the thrust chamber 222 reduces the pressure on the first rotating structure 227 and allows the net force on the high-pressure drive shaft 30 to move the high-pressure drive shaft 30 in the rearward direction. Similarly, for the illustrated embodiment, the reduced pressure supplied to the thrust chamber 222 reduces the pressure on the second rotating structure 230 and allows the net force on the low-pressure drive shaft 34 to move the low-pressure drive shaft 34 in the forward direction.

[0218] Now refer to Figure 9 The present disclosure illustrates a flowchart of one embodiment of a method 300 for balancing rotor thrust on a thrust bearing 118 of a turbine. Method 300 can be used on any turbine, such as, but not limited to, those described above. Figure 1 The gas turbine engine 10. Furthermore, method 300 can be broadly compared with... Figure 2-8 It can be used with the system 200 described herein, or with any other capable system.

[0219] In step 302, method 300 may include using a waveguide sensor 202 coupled to the thrust bearing 118 to transmit a vibration frequency from the thrust bearing 118 to the outside of the turbine. In some embodiments, the vibration frequency is the ball-passing frequency, such as the ball-passing frequency on the outer race 130 of the thrust bearing 118. In an exemplary embodiment, another step 304 includes transmitting the vibration frequency to a control sensor communicatively coupled to the control system. In one embodiment, the control sensor is a piezoelectric sensor 208. The control system may be... Figure 4 The FADEC control system 210.

[0220] In one embodiment, method 300 includes, at 306, comparing the amplitude of a first ball-passing frequency transmitted from a first waveguide sensor 201 at the front end 209 of the thrust bearing 118 relative to the centerline 12 with the amplitude of a second ball-passing frequency transmitted from a second waveguide sensor 203 at the rear end 211 of the thrust bearing 118 relative to the centerline 112. Furthermore, method 300 may include, at 308, determining the direction of the rotor thrust acting on the rotary drive shaft 31 relative to the centerline 12 based on the difference between the amplitudes of the first and second ball-passing frequencies. It should be understood that the rotary drive shaft 31 may be a high-pressure drive shaft 30, a low-pressure drive shaft 34, or any other suitable drive shaft.

[0221] At 310, exemplary method 300 includes determining whether thrust bearing 118 is in a crossed state. For example, determining the crossed state may include determining whether the ball pass frequency of thrust bearing 118 is below a first threshold. For example, a ball pass frequency below a first threshold of system 200 may indicate that thrust bearing 118 is in a crossed state. In the depicted embodiment, another step 312 includes changing the pressure of thrust chamber 222 in contact with rotary drive shaft 31 in response to the crossed state of thrust bearing 118. For example, method 300 may include transmitting a signal from a control system (such as FADEC system 210) to valve 216. In some embodiments, valve 216 is coupled to and receives pressurized fluid from and from compressor section 23 of turbine (such as engine 10), and selectively delivers pressurized fluid to thrust chamber 222 in contact with rotary drive shaft 31. In other embodiments, pressurized fluid may be received from turbine section 29. In the depicted embodiment, pressure in thrust chamber 222 acts on rotating structure 226 defining thrust chamber 222. Therefore, exemplary method 300 includes changing the force on the rotary drive shaft 31 (such as high-pressure drive shaft 30 or low-pressure drive shaft 34) at 314 to disengage the thrust bearing 118 from the crossed state. For example, the changed pressure of the thrust chamber 222 can change the pressure acting on the region of the rotating structure 226. This changed pressure can change the force applied to the rotary drive shaft 31.

[0222] Now refer to Figure 10The following flowchart illustrates another embodiment of a method 400 for balancing rotor thrust on a thrust bearing 118 of a turbine, according to aspects of this disclosure. Method 400 may have generally similar steps to method 300. For example, method 400 may share steps 306-314 with method 300. In step 402, method 400 may include transmitting a ball-passing frequency from the thrust bearing 118 to the outside of the turbine using a waveguide sensor 202 coupled to the thrust bearing 118. In an exemplary embodiment, another step 404 includes transmitting the ball-passing frequency to a control sensor communicatively coupled to a control system. In one embodiment, the control sensor is a piezoelectric sensor 208. The control system may be... Figure 4 The FADEC control system 210.

[0223] This written description uses exemplary embodiments to disclose the invention, including the best mode, and also enables those skilled in the art to practice the invention, including making and using any apparatus or system and performing any incorporated methods. The patentability of the invention is defined by the claims and may include other examples that would occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not significantly different from the literal language of the claims.

Claims

1. A rotor thrust balancing system for a turbine, wherein the turbine defines a centerline extending the length of the turbine, the system comprising: A rotary drive shaft connects the turbine section and the compressor section of the turbine; A thrust bearing that supports the rotary drive shaft of the turbine; The thrust bearing includes: Multiple ball bearings; Inner race, which is connected to the rotary drive shaft; and The outer race is connected to the fixed structure; A first waveguide sensor, comprising a first end connected to the front end of the outer race relative to the centerline and a second end located outside the turbine, wherein the waveguide sensor transmits ball bearing frequency from the thrust bearing to the second end of the waveguide sensor; A second waveguide sensor, wherein a first end of the second waveguide sensor is connected to the rear end of the outer race relative to the centerline; and The control system is configured as follows: The amplitude of the frequency through which the first ball passes, transmitted from the first waveguide sensor, is compared with the amplitude of the frequency through which the second ball passes, transmitted from the second waveguide sensor; and The direction of the rotor thrust acting on the rotary drive shaft relative to the centerline is determined based on the difference between the amplitude of the first ball passing frequency and the second ball passing frequency.

2. The system according to claim 1, characterized in that, The system also includes: A thrust chamber that contacts the rotary drive shaft, wherein the thrust chamber is pressurized to change the force on the rotary drive shaft forward or backward relative to the centerline.

3. The system according to claim 2, characterized in that, The thrust chamber is located in the turbine section of the turbine.

4. The system according to claim 2, characterized in that, The thrust chamber is located in the compressor section of the turbine.

5. The system according to claim 1, characterized in that, The system also includes: A control sensor, located at the second end of the first waveguide sensor, is used to transmit the frequency of the balls of the thrust bearing to the control system.

6. The system according to claim 5, characterized in that, The control system communicates with the valve to decrease or increase the pressure supplied to the thrust chamber, wherein the thrust chamber changes the force on the rotary drive shaft forward or backward relative to the centerline.

7. The system according to claim 5, characterized in that, The control sensor is a piezoelectric sensor.

8. The system according to claim 5, characterized in that, The control system is a full authority engine control system.

9. The system according to claim 1, characterized in that, The rotary drive shaft is a high-pressure drive shaft that connects the high-pressure turbine section to the high-pressure compressor section.

10. The system according to claim 1, characterized in that, The rotary drive shaft is a low-pressure drive shaft that connects the low-pressure turbine section to at least one of the low-pressure compressor section or the fan section.

11. A method for balancing rotor thrust on a thrust bearing of a turbine, wherein the turbine defines a centerline extending the length of the turbine, the method comprising: The ball bearing pass frequency is transmitted from the thrust bearing to the outside of the turbine using a first waveguide sensor and a second waveguide sensor connected to the thrust bearing. The ball bearings are transmitted via frequency to a control sensor in the control system, which is then coupled to the communication ground. The amplitude of the frequency at which the first ball passes through, transmitted from the first waveguide sensor at the front end of the thrust bearing relative to the centerline, is compared with the amplitude of the frequency at which the second ball passes through, transmitted from the second waveguide sensor at the rear end of the thrust bearing relative to the centerline. The direction of the rotor thrust acting on the rotary drive shaft relative to the centerline is determined based on the difference between the amplitude of the first ball passing frequency and the second ball passing frequency. Determine whether the thrust bearing is in a crossed state; as well as Change the force on the rotary drive shaft to disengage the thrust bearing from the crossed state.

12. The method according to claim 11, characterized in that, The method further includes: Determine whether the frequency of the balls passing through the thrust bearing is lower than a first threshold.

13. The method according to claim 11, characterized in that, The method further includes: The pressure in the thrust chamber that is in contact with the rotary drive shaft changes in response to the cross-state of the thrust bearing.

14. The method according to claim 11, characterized in that, The method further includes: The signal is transmitted from the control system to a valve, which is connected to and receives pressurized fluid from the compressor section of the turbine, and selectively delivers the pressurized fluid to a thrust chamber in contact with the rotary drive shaft.

15. The method according to claim 14, characterized in that, The method further includes: The pressure of the thrust chamber is changed, wherein the changed pressure of the thrust chamber alters the force applied to the rotary drive shaft.

16. A method for determining the direction of rotor thrust on a thrust bearing of a turbine, wherein the turbine defines a centerline extending the length of the turbine, the method comprising: The ball bearing pass frequency is transmitted from the thrust bearing to the outside of the turbine using a first waveguide sensor and a second waveguide sensor connected to the thrust bearing. The ball bearings are transmitted via frequency to a control sensor coupled to the control system via communication; and The amplitude of the frequency at which the first ball passes through, transmitted from the first waveguide sensor at the front end of the thrust bearing relative to the centerline, is compared with the amplitude of the frequency at which the second ball passes through, transmitted from the second waveguide sensor at the rear end of the thrust bearing relative to the centerline.

17. The method according to claim 16, characterized in that, The method further includes: The direction of the rotor thrust acting on the rotary drive shaft relative to the centerline is determined based on the difference between the amplitude of the first ball passing frequency and the second ball passing frequency.

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