Gearbox thermal control system

Abstract

A system for a gas turbine engine includes a gearbox including a coolant inlet, a coolant outlet, and a metal portion, a first coolant supply line in fluid communication with the coolant inlet of the gearbox, a first temperature sensor in thermal communication with the first coolant supply line, and a second temperature sensor in thermal communication with the second coolant supply line. A second coolant supply line in fluid communication with a coolant outlet of the gearbox, a second temperature sensor in thermal communication with the second coolant supply line, a third temperature sensor in thermal communication with a metal portion of the gearbox, a bypass line coupling the first coolant supply line to the second coolant supply line, a bypass valve disposed at a junction of the second coolant supply line and the bypass line, and a controller configured to actuate the bypass valve.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a temperature control system for a reduction gearbox. BACKGROUND

[0002] Lubricating oil systems for turbine systems can help prevent mechanical wear in components of the turbine system (e.g., generators, bearings, gears). More specifically, lubricating oil systems can provide a consistent and steady flow of oil to turbine system components (e.g., reduction gearboxes) in order to lubricate, clean component contact surfaces, and remove heat generated by moving and stationary turbine system components. The temperature of the lubricating oil flowing through the components of the turbine system can depend, at least in part, on operating characteristics (e.g., temperature) of the turbine system and turbine system components. As a result, conventional lubricating oil systems can include heat exchangers that can adjust the temperature of the lubricating oil according to the operating characteristics of the turbine system. Using a cooling fluid (e.g., water or other cooling fluid), the heat exchangers of the lubricating oil system can adjust the temperature of the lubricating oil before the lubricating oil flows to the turbine system. BRIEF DESCRIPTION OF DRAWINGS

[0003] The complete and enabling disclosure of the present disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification, which is to be construed in view of the accompanying drawings, wherein:

[0004] Figure 1 is a schematic diagram of an exemplary gas turbine engine.

[0005] Figure 2 is a schematic diagram of a gearbox system for an exemplary gas turbine engine.

[0006] Figure 3 is a block diagram illustrating the operation of the gearbox system.

[0007] Figure 4 is a schematic diagram of a controller.

[0008] Figure 5 is a diagram of an exemplary method for operating an exemplary gas turbine engine. DETAILED DESCRIPTION

[0009] Reference will now be made in detail to the current embodiments of the present disclosure, one or more examples of which are illustrated in the drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the present disclosure.

[0010] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, unless otherwise indicated, the description herein is to be considered as illustrative only and not as restricting the scope of the disclosure.

[0011] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0012] As used herein, the terms "first," "second," "third," and other ordinal terms are used to distinguish one component from another and do not necessarily indicate position or importance of the individual components.

[0013] The terms "upstream" and "downstream" refer to the relative direction with respect to fluid flow in a fluid pathway. For example, "upstream" refers to the direction from which the fluid flows, and "downstream" refers to the direction to which the fluid flows.

[0014] The present disclosure relates generally to temperature control of a gearbox for use during operation of a gas turbine engine having a coolant, such as lubricating oil. When the gearbox is overheated, the gear teeth can wear, shortening the life of the gearbox. When the gearbox is cold, the viscosity of the coolant can slow the operation of the gears, reducing the overall efficiency of the gearbox. There is an opportunity for the system to control the coolant temperature to increase the viscosity (and increase efficiency), while reducing or inhibiting wear of the overheated components.

[0015] The use of a bypass line in the coolant supply system allows for more fine-grained temperature control of the gearbox, allowing for increased efficiency while inhibiting wear of the gear teeth. The bypass line provides heated coolant to the gearbox by bypassing the heat exchanger (preventing the heat exchanger from cooling the coolant) or providing heated coolant from the outlet of the gearbox back to the inlet of the gearbox. A controller operates the bypass line to raise the temperature of the coolant to a specified temperature based on current engine operating conditions (such as cruising, climbing, or landing), optimizing the efficiency of the gearbox.

[0016] Referring now to Figure 1 , a schematic cross-sectional view of an engine 100 (e.g., a gas turbine engine) is provided in accordance with example embodiments of the present disclosure. In particular, Figure 1 A gas turbine engine is provided having a rotor assembly with single stage unshrouded rotor blades. In this manner, the rotor assembly can be referred to herein as an "unshrouded fan," or the entire engine 100 can be referred to as an "unshrouded gas turbine engine." Further, Figure 1 The engine 100 of

[0017] For reference, the engine 100 defines an axial direction A, a radial direction R, and a circumferential direction C. Further, the engine 100 defines an axial centerline or longitudinal axis 112 that extends along the axial direction A. Generally, the axial direction A extends parallel to the longitudinal axis 112, the radial direction R extends outwardly and inwardly from the longitudinal axis 112 in a direction perpendicular to the axial direction A, and the circumferential direction extends three hundred and sixty degrees (360°) about the longitudinal axis 112. The engine 100 extends, for example, along the axial direction A between a forward end 114 and an aft end 116.

[0018] The engine 100 includes a turbine 120 and a rotor assembly, also referred to as a fan section 150, located upstream of the turbine. Generally, the turbine 120 includes, in serial flow order, a compressor section, a combustion section, a turbine section, and an exhaust section. In particular, as shown, the turbine 120 includes a core case 122 that defines an annular core inlet 124. The core case 122 also at least partially encloses a low pressure system and a high pressure system. For example, the illustrated core case 122 at least partially encloses and supports a booster or low pressure (“LP”) compressor 126 for pressurizing air entering the turbine 120 through the annular core inlet 124. A high pressure (“HP”) multi-stage axial compressor 128 receives the compressed air from the LP compressor 126 and further increases the pressure of the air. The pressurized air flows downstream to a combustor 130 of the combustion section where fuel is injected into the pressurized air stream and ignited to raise the temperature and energy level of the pressurized air. Figure 1

[0019] It should be appreciated that, as used herein, the terms “high / low speed” and “high / low pressure” are used interchangeably for the high pressure / high speed system and the low pressure / low speed system. Further, it should be appreciated that the terms “high” and “low” are used in the same context to distinguish between the two systems and do not imply any absolute speed and / or pressure values.

[0020] The high energy combustion products flow downstream from the combustor 130 to a HP turbine 132. The HP turbine 132 drives the HP compressor 128 through a HP shaft 136. In this regard, the HP turbine 132 is drivingly coupled with the HP compressor 128. The high energy combustion products then flow to a LP turbine 134. The LP turbine 134 drives the LP compressor 126 and components of the fan section 150 through a LP shaft 138. In this regard, the LP turbine 134 is drivingly coupled with the LP compressor 126 and components of the fan section 150. In this exemplary embodiment, the LP shaft 138 is coaxial with the HP shaft 136. After driving each of the turbines 132, 134, the combustion products exit the turbine 120 through a turbine exhaust nozzle 140.

[0021] ​Therefore, turbine 120 defines a working gas flow path or core duct 142 extending between an annular core inlet 124 and turbine exhaust nozzle 140. Core duct 142 is an annular duct located approximately inside the core shroud 122 in the radial direction R. Core duct 142 (e.g., through the working gas flow path of turbine 120) may be referred to as a second flow.

[0022] Fan section 150 includes fan 152, which, in this exemplary embodiment, is the main fan. For Figure 1 In the embodiment shown, fan 152 is an open rotor or ductless fan 152. In this way, engine 100 can be referred to as an open rotor engine.

[0023] As shown in the figure, fan 152 includes fan blades 154 ( Figure 1 An array of (only one is shown in the image) is used. The fan blades 154 are rotatable, for example, about the longitudinal axis 112. As described above, the fan 152 is drivenly connected to the LP turbine 134 via the LP shaft 138. For Figure 1 In the illustrated embodiment, fan 152 is connected to LP shaft 138 via gearbox 155 (e.g., reduction gearbox), for example in an indirect drive or gear drive configuration.

[0024] Furthermore, the array of fan blades 154 can be arranged at equal intervals around the longitudinal axis 112. Each fan blade 154 has a root and a tip, and a span defined therebetween. Each fan blade 154 defines a central blade axis 156. In this embodiment, each fan blade 154 of the fan 152 is capable of rotating about its central blade axis 156, for example, rotating in unison with each other. One or more actuators 158 are provided to facilitate this rotation, and thus can be used to change the pitch of the fan blades 154 about their respective central blade axes 156.

[0025] Fan section 150 further includes a fan guide vane array 160, which includes fan guide vanes 162 disposed around a longitudinal axis 112. Figure 1 (Only one is shown in the image). In this embodiment, the fan guide vane 162 cannot rotate about the longitudinal axis 112. Each fan guide vane 162 has a root and a tip, and a span defined between them. Figure 1 As shown, the fan guide vane 162 may be unshielded, or alternatively, it may be covered by an annular shroud, for example, spaced outward from the tip of the fan guide vane 162 along the radial direction R, or attached to the fan guide vane 162.

[0026] Each fan guide vane 162 defines a central blade axis 164. In this embodiment, each fan guide vane 162 of the fan guide vane array 160 is rotatable about its respective central blade axis 164, for example, rotating in unison with each other. One or more actuators 166 are provided to facilitate this rotation and are therefore used to change the pitch of the fan guide vane 162 about its respective central blade axis 164. However, in other embodiments, each fan guide vane 162 may be fixed or unable to pitch about its central blade axis 164. The fan guide vanes 162 are mounted on a fan shroud 170.

[0027] like Figure 1 As shown, in addition to the ductless fan 152, a ducted fan 184 is included downstream of fan 152, such that engine 100 includes both a ducted fan and a ductless fan, both used to generate thrust by the movement of air that does not pass through at least a portion of turbine 120 (e.g., in the illustrated embodiment, not through HP compressor 128 and combustion chamber). The ducted fan 184 is rotatable about the same axis as the fan blades 154 (e.g., longitudinal axis 112). In the illustrated embodiment, the ducted fan 184 is driven by LP turbine 134 (e.g., coupled to LP shaft 138). In the illustrated embodiment, as described above, fan 152 may be referred to as the primary fan, while the ducted fan 184 may be referred to as the secondary fan. It should be understood that these terms "primary" and "secondary" are convenient terms and do not imply any particular importance, right, etc.

[0028] The duct fan 184 includes multiple fan blades arranged in a single stage (in Figure 1 (Not separately marked), so that the duct fan 184 can be referred to as a single-stage fan. The fan blades of the duct fan 184 can be arranged at equal intervals around the longitudinal axis 112. Each blade of the duct fan 184 has a root and a tip and a span defined between them.

[0029] The fan shroud 170 annularly surrounds at least a portion of the core shroud 122 and is generally positioned radially R outside at least a portion of the core shroud 122. Specifically, a downstream section of the fan shroud 170 extends over the front portion of the core shroud 122 to define a fan duct flow path, or simply to define a fan duct 172. According to this embodiment, the fan flow path or fan duct 172 can be understood as forming at least a portion of a third flow of the engine 100.

[0030] Incoming air enters through fan duct inlet 176, passes through fan duct 172, and exits through fan exhaust nozzle 178 to generate propulsive thrust. Fan duct 172 is an annular duct, typically located radially R outside core duct 142. Fan shroud 170 and core shroud 122 are connected together and are supported by a plurality of substantially radially extending, circumferentially spaced fixed supports 174. Figure 1 (Only one support is shown in the image.) The fixed support 174 may each have an aerodynamic profile to guide airflow therefrom. In addition to the fixed support 174, other supports may be used to connect and support the fan shroud 170 and / or the core shroud 122. In many embodiments, the fan duct 172 and the core duct 142 may extend at least partially together (typically axially) on opposite sides (e.g., opposite radial sides) of the core shroud 122. For example, the fan duct 172 and the core duct 142 may each extend directly from the leading edge 144 of the core shroud 122 and may extend partially together axially on opposite radial sides of the core shroud 122.

[0031] Engine 100 also defines or includes an inlet duct 180. Inlet duct 180 extends between engine inlet 182 and annular core inlet 124 / fan duct inlet 176. Engine inlet 182 is generally defined at the front end of fan shroud 170 and positioned in the axial direction A between fan 152 and fan guide vane array 160. Inlet duct 180 is an annular duct positioned in the radial direction R inside fan shroud 170. Air flowing downstream along inlet duct 180 is diverted by a fan duct splitter or the leading edge 144 of core shroud 122, and is not necessarily uniformly diverted into core duct 142 and fan duct 172. In the illustrated embodiment, inlet duct 180 is wider than core duct 142 in the radial direction R. Inlet duct 180 is also wider than fan duct 172 in the radial direction R.

[0032] It is worth noting that, for the illustrated embodiment, engine 100 includes one or more features to enhance the third-flow thrust Fn. 3S(For example, thrust resulting from the airflow through the fan duct 172, which exits through the fan exhaust nozzle 178, is at least partially generated by the ducted fan 184.) In particular, the engine 100 further includes an array of inlet guide vanes 186 positioned in the inlet duct 180 upstream of the ducted fan 184 and downstream of the engine inlet 182. The array of inlet guide vanes 186 is arranged about the longitudinal axis 112. For this embodiment, the inlet guide vanes 186 are not rotatable about the longitudinal axis 112. Each inlet guide vane 186 defines a central vane axis (not labeled for clarity) and is rotatable about its respective central vane axis, for example, in unison with one another. In this manner, the inlet guide vanes 186 can be considered variable geometry components. One or more actuators 188 are provided to facilitate such rotation, and thus can be used to vary the pitch of the inlet guide vanes 186 about their respective central vane axes. However, in other embodiments, each inlet guide vane 186 can be fixed or non-pitchable about its central vane axis.

[0033] Further, positioned downstream of the ducted fan 184 and upstream of the fan duct inlet 176, the engine 100 includes an array of outlet guide vanes 190. Like the array of inlet guide vanes 186, the array of outlet guide vanes 190 is not rotatable about the longitudinal axis 112. However, for the illustrated embodiment, unlike the array of inlet guide vanes 186, the array of outlet guide vanes 190 is configured as fixed-pitch outlet guide vanes.

[0034] Further, it should be appreciated that, for the illustrated embodiment, the fan exhaust nozzle 178 of the fan duct 172 is further configured as a variable geometry exhaust nozzle. In this manner, the engine 100 includes one or more actuators 192 for adjusting the variable geometry exhaust nozzle. For example, the variable geometry exhaust nozzle can be configured to vary the total cross-sectional area (e.g., the area of the nozzle in a plane perpendicular to the longitudinal axis 112) to adjust the amount of thrust generated based on one or more engine operating conditions (e.g., the temperature, pressure, mass flow rate, etc. of the airflow through the fan duct 172). Fixed geometry exhaust nozzles can also be employed.

[0035] The combination of the array of inlet guide vanes 186 positioned upstream of the ducted fan 184, the array of outlet guide vanes 190 positioned downstream of the ducted fan 184, and the fan exhaust nozzle 178 can result in more efficient third flow thrust Fn 3S Further, by introducing variability in the geometry of the inlet guide vanes 186 and the fan exhaust nozzle 178, the engine 100 is able to generate more efficient third flow thrust Fn3S including takeoff and climb (where maximum total engine thrust Fn total is typically required) and cruise (where a lower amount of total engine thrust Fn total is typically required).

[0036] Further, still referring to Figure 1 , in example embodiments, the air passing through the fan duct 172 can be relatively cooler (e.g., lower temperature) than the one or more fluids used in the turbine 120. As such, one or more heat exchangers 200 can be positioned in thermal communication with the fan duct 172. For example, one or more heat exchangers 200 can be disposed within the fan duct 172 and used to cool one or more fluids from the core engine using the air passing through the fan duct 172 as a resource for removing heat from the fluids (e.g., compressor bleed air, oil, or fuel).

[0037] Although not shown, the heat exchanger 200 can be an annular heat exchanger that extends substantially 360 degrees (e.g., at least 300 degrees, such as at least 330 degrees) in the fan duct 172. In this manner, the heat exchanger 200 can effectively use the air passing through the fan duct 172 to cool one or more systems of the engine 100 (e.g., a lubrication oil system, compressor bleed air, electrical components, etc.). The heat exchanger 200 uses the air passing through the fan duct 172 as a heat sink and correspondingly increases the temperature of the air downstream of the heat exchanger 200 and exiting the fan exhaust nozzle 178.

[0038] Referring now to Figure 2 , a schematic view of a gear box system 202 for the gear box 155 is shown. The gear box system 202 includes the gear box 155 and a cooling system 204. The gear box 155 includes a coolant inlet 206, a coolant outlet 208, and a metal portion 210. The metal portion 210 of the gear box 155 is a component of the gear box 155 formed of metal (e.g., a pure metal or a metal alloy), such as a housing, a flange, a ring gear, or another fixed element.

[0039] The cooling system 204 includes a pump 212, a coolant reservoir 214, a first coolant supply line 216, a second coolant supply line 218, a gear box bypass line 220, a gear box bypass valve 222, the heat exchanger 200, a heat exchanger bypass line 224, a heat exchanger bypass valve 226, a first temperature sensor 228, a second temperature sensor 230, a third temperature sensor 232, and a controller 234.

[0040] A pump 212 provides coolant from a coolant reservoir 214 to the gear case 155. Specifically, the pump 212 is disposed upstream of the coolant inlet 206 of the gear case and provides coolant to the gear case 155. The coolant reservoir 214 contains at least some of the coolant used in the gear case system 202. The coolant can be lubricating oil.

[0041] A first coolant supply line 216 is in fluid communication with the coolant inlet 206 of the gear case and the pump 212. The pump 212 provides coolant to the coolant inlet 206 through the first coolant supply line 216. A second coolant supply line 218 is in fluid communication with the coolant outlet of the gear case and the coolant reservoir 214. The coolant outlet 208 provides coolant to the coolant reservoir 214 through the second coolant supply line 218.

[0042] A gear case bypass line 220 connects the first coolant supply line 216 to the second coolant supply line 218, bypassing the coolant reservoir 214. The gear case bypass line 220 provides coolant heated by the gear case 155 from the coolant outlet 208 to the first coolant supply line 216, thereby heating the coolant provided to the coolant inlet 206. The heated coolant increases the efficiency of the gear case 155 during certain engine operations, which can increase to a target efficiency for improving operation of the engine 100. Certain engine conditions can include instances where the coolant, which can include lubricant, is below a certain temperature (e.g., 100 degrees Fahrenheit) such that the viscosity of the coolant increases wear on the gear case 155 and decreases the efficiency of the gear case 155, such as engine start-up, idle in cold weather conditions, flight idle, low speed cruise, and combinations thereof.

[0043] A gear case bypass valve 222 is disposed at the junction of the second coolant supply line 218 and the gear case bypass line 220 and provides heated coolant to the gear case bypass line 220. Specifically, the gear case bypass valve 222 is actuatable to allow a certain amount of heated coolant to enter the gear case bypass line 220. The gear case bypass valve 222 is actuatable to a specified duty cycle, i.e., a percentage of time that the gear case bypass valve 222 is fully open over a specified period of time, to provide a certain amount of heated coolant. The gear case bypass valve 222 can be an active valve or a passive valve. An active valve includes a valve that is actuatable by a controller (described below) to open and close, such as an electromagnetic valve. A passive valve includes a valve that opens and closes upon contact with heated coolant, such as a thermostatic valve having a heat-sensitive substance with a certain melting point to open or close the valve at a certain temperature, a shape memory alloy that deforms at a certain temperature to open or close the valve, or combinations thereof.

[0044] The heat exchanger 200 cools heated coolant from the coolant outlet 208 so that the pump 212 can supply coolant to cool the gear case 155. In particular, the heat exchanger 200 includes an inlet 236 and an outlet 238, the second coolant supply line 218 is in fluid communication with the inlet 236, and the first coolant supply line 216 is in fluid communication with the outlet 238. Heated coolant flows from the second coolant supply line 218 into the inlet 236 of the heat exchanger 200, the heat exchanger 200 cools the heated coolant, and the coolant flows out of the outlet 238 of the heat exchanger 200 to the pump 212. The heat exchanger 200 can be an air-cooled oil cooler (ACOC), a fuel-cooled oil cooler (FCOC), a different type of cooler, or a combination thereof.

[0045] To increase the temperature of the coolant provided to the pump 212, a heat exchanger bypass line 224 connects the second coolant supply line 218 to the first coolant supply line 216, bypassing the heat exchanger 200, so that a particular amount of heated coolant is not cooled by the heat exchanger 200. In particular, the heat exchanger bypass line 224 has an inlet 240 upstream of the inlet 236 of the heat exchanger 200 and an outlet 242 downstream of the outlet 238 of the heat exchanger 200. A heat exchanger bypass valve 226 is disposed in the heat exchanger bypass line 224 and provides heated coolant to the first coolant supply line 216. As described above with reference to the gear case bypass valve 222, the heat exchanger bypass valve 226 can be actuated to a specified duty cycle to provide a specified amount of heated coolant to the first coolant supply line 216. The heat exchanger bypass valve 226 can be an active valve or a passive valve, such as those described above with reference to the gear case bypass valve 222.

[0046] A first temperature sensor 228 collects first temperature data of the coolant in the first coolant supply line 216. In particular, the first temperature sensor 228 is disposed between the outlet 238 of the heat exchanger 200 and the coolant inlet 206 of the gear case 155. The first temperature data is indicative of the temperature of the coolant entering the gear case 155.

[0047] The second temperature sensor 230 collects second temperature data from the coolant in the second coolant supply line 218. Specifically, the second temperature sensor 230 is disposed between the coolant outlet 208 of the gearbox and the inlet 236 of the heat exchanger 200. The second temperature data indicates the temperature of the heated coolant exiting the gearbox 155. The first temperature data and the second temperature data indicate the amount of heat transferred from the gearbox 155 to the coolant, which indicates how much the gearbox 155 is cooled by the coolant. In particular, the difference between the first temperature data and the second temperature data indicates the amount of heat transferred from the gearbox 155. This difference can be a measure of the efficiency of the gearbox 155, as described below. Additionally, the specific amount of heat transferred to the gearbox 155 can be determined based on additional collected data, such as the mass flow rate of the coolant (which is based on the speed of the pump 212 and the size of the first coolant supply line 216) and the thermal capacity of the gearbox 155.

[0048] The third temperature sensor 232 collects third temperature data directly from the gearbox 155. Specifically, the third temperature sensor 232 is in thermal contact with the metal portion 210 of the gearbox 155 to directly measure the temperature of the gearbox 155. The third temperature data can be an additional measure of the efficiency of the gearbox 155, a backup temperature measurement for determining excessive wear on the gearbox 155, or a combination thereof.

[0049] The controller 234 is a computing device for operating components of the engine 100, such as a FADEC, EEC, or OCM. The controller 234 is configured to control the temperature of the coolant entering the gearbox 155. Specifically, the controller 234 collects the first temperature data, the second temperature data, and the third temperature data to determine the temperature of the gearbox 155 and the temperature of the coolant entering and exiting the gearbox 155. The controller 234 is configured to actuate the gearbox bypass valve 222, the heat exchanger bypass valve 226, or both to adjust the temperature of the coolant. Specifically, by actuating at least one of the gearbox bypass valve 222 or the heat exchanger bypass valve 226, the temperature of the coolant in the first coolant supply line 216 is increased, which increases the temperature (and efficiency) of the gearbox 155. The controller 234 is configured to actuate the gearbox bypass valve 222, the heat exchanger bypass valve 226, or both to a specified duty cycle to provide a specific amount of heated coolant to the first coolant supply line 216.

[0050] The controller 234 can be configured to heat or cool the gearbox 155 to a specified temperature. The specified temperature can be based on a specified efficiency target for the gearbox 155 for a particular engine operation of the gas turbine engine, such as cold start, takeoff, cruise, or landing. As described below, an example specified temperature can be between 200-300 °F. To heat the gearbox 155, the controller 234 can be configured to actuate the gearbox bypass valve 222, the heat exchanger bypass valve 226, or both, when the third temperature data indicates that the temperature of the metal portion 210 of the gearbox 155 is below the specified temperature, thereby providing heated coolant from the gearbox bypass line 220 or the second coolant supply line 218 to the first coolant supply line 216. Thus, the controller 234 provides a closed loop temperature control system to control the temperature of the coolant and the gearbox 155.

[0051] Additionally, the controller 234 can be configured to determine a temperature difference between the first temperature data (indicating a first temperature of the coolant upstream of the gearbox 155) and the second temperature data (indicating a second temperature of the coolant downstream of the gearbox 155), and actuate the gearbox bypass valve 222, the heat exchanger bypass valve 226, or both, when the temperature difference exceeds a threshold value. The threshold value can be a particular temperature difference at which the coolant maintains the gearbox 155 at the specified temperature. Further, the controller 234 can be configured to actuate the gearbox bypass valve 222, the heat exchanger bypass valve 226, or both, when the third temperature data indicates that the temperature of the metal portion 210 of the gearbox 155 is below the specified temperature.

[0052] To cool the gearbox 155, the controller 234 can be configured to close the gearbox bypass valve 222, the heat exchanger bypass valve 226, or both, when one or more of the first temperature data, the second temperature data, or the third temperature data indicates that the temperature of the gearbox 155 is above a second specified temperature. The second specified temperature can be a temperature at which the gearbox 155 begins to wear, and maintaining the temperature of the gearbox 155 between the specified temperature and the second specified temperature provides efficiency benefits of the gearbox 155 while inhibiting or preventing damage to components of the gearbox 155. The second specified temperature is higher than the specified temperature. Upon closing the gearbox bypass valve 222, the heat exchanger bypass valve 226, or both, the coolant is stopped from being directed to the gearbox bypass line 220, the heat exchanger bypass line 224, or both.

[0053] Reference is now made to Figure 3FIG. 3 shows a diagram illustrating operation of the gearbox system 202. The controller 234 can be configured to determine an operating condition of the engine 100 and determine a specified temperature based on the operating condition. Generally, the specified temperature is determined to achieve a specified efficiency target of the gearbox 155. Specifically, the specified temperature is a maximum temperature of the coolant at the coolant outlet 208 of the gearbox 155 before wear or damage occurs. The controller 234 is configured to maintain the coolant at a substantially constant temperature within a threshold of the specified temperature, thereby reducing friction between components of the gearbox 155 while inhibiting excessive wear.

[0054] The controller 234 includes a coolant module 300 and a valve module 302. The coolant module 300 collects data regarding operation of the engine 100, labeled as operating data 304. The operating data 304 includes data from different components of the engine 100. More specifically, the operating data 304 can include throttle position data 306, ambient air pressure data 308, altitude data 310, engine inlet temperature data 312, speed data 314 (e.g., speed of the HP turbine 132, speed of the LP turbine 134, or engine core speed), fuel temperature data 316, oil temperature data 318, and combinations thereof.

[0055] Based on the operating data 304, the coolant module 300 can identify an operating condition 320 of the engine 100. The operating condition 320 is an indicator of how the engine 100 (and aircraft) is operating. The operating condition 320 can be one of takeoff, cruise, or landing. The coolant module 300 can identify the operating condition 320 with a lookup table, such as Table 1 below:

[0056]

[0057] Table 1: Operating Condition Lookup Table

[0058] In Table 1, “O.C.” is the operating condition 320. The coolant module 300 can compare the operating data 304 to the values in the lookup table to identify the operating condition 320 and, in turn, determine a specified coolant temperature 322.

[0059] Upon determining the specified coolant temperature 322, the valve module 302 determines a valve position 324 for the gearbox bypass valve 222 and the heat exchanger bypass valve 226 to heat or cool the coolant. Specifically, the valve module 302 can include a lookup table that determines the valve position 324 based on the operating condition 320 and the specified coolant temperature 322.

[0060] O.C. Designated coolant temperature GB bypass valve HX bypass valve Take-off 200°F Off Off Cruise 250°F Off On Landing 300°F Off Off Cold start 200°F On On

[0061] Table 2: Valve Position Lookup Table

[0062] In Table 2, “GB bypass valve” is the position of the gearbox bypass valve 222, and “HX bypass valve” is the position of the heat exchanger bypass valve 226. Upon determining the valve position 324, the controller 234 actuates the gearbox bypass valve 222 and the heat exchanger bypass valve 226 to the valve position 324. The controller 234 then collects updated values of the first temperature data, the second temperature data, the third temperature data, and the operating data 304 to determine whether to adjust the temperature of the coolant.

[0063] Referring now to Figure 4 Operation of a controller 400, such as the controller 234 of the gearbox system 202, will be described. In at least certain embodiments, the controller 400 can include one or more computing devices 402. The computing device 402 can include one or more processors 402A and one or more memory devices 402B. The one or more processors 402A can include any suitable processing device, such as a microprocessor, microcontroller, integrated circuit, logic device, and / or other suitable processing devices. The one or more memory devices 402B can include one or more computer-readable media, including, but not limited to, non-transitory computer-readable media, RAM, ROM, hard drives, flash drives, and / or other memory devices.

[0064] The one or more memory devices 402B can store information accessible by the one or more processors 402A, including computer-readable instructions 402C that can be executed by the one or more processors 402A. The instructions 402C can be any set of instructions that, when executed by the one or more processors 402A, cause the one or more processors 402A to perform operations. In some embodiments, the instructions 402C can be executed by the one or more processors 402A to cause the one or more processors 402A to perform operations such as any operations and functions for which the controller 400 and / or the computing device 402 are configured, as described herein for operating the gearbox system 202, and / or any other operations or functions of the one or more computing devices 402. The instructions 402C can be software written in any suitable programming language or can be implemented in hardware. Additionally, and / or alternatively, the instructions 402C can be executed on the one or more processors 402A in logically and / or virtually separate threads of execution. The one or more memory devices 402B can further store data 402D that can be accessed by the one or more processors 402A. For example, the data 402D can include data indicative of power flow, data indicative of engine / aircraft operating conditions, and / or any other data and / or information described herein.

[0065] The computing device 402 can also include a network interface 402E for communicating with other components of the gear box system 202, for example, including the carrier including the gear box system 202. For example, in the illustrated embodiment, as discussed above, the gear box system 202 includes one or more sensors for sensing data indicative of one or more parameters (e.g., temperature, altitude, air pressure, etc.). The controller 400 is operably coupled to the one or more sensors by, for example, the network interface, such that the controller 400 can receive data indicative of various operating parameters sensed by the one or more sensors during operation. In this manner, the controller 400 can be configured to operate the gear box system 202 in response to, for example, data sensed by the one or more sensors.

[0066] The network interface 402E can include any suitable components for interfacing with one or more networks, including for example, transmitters, receivers, ports, controllers, antennas, and / or other suitable components.

[0067] The technology discussed herein makes reference to computer-based systems and actions performed by and information sent to and from computer-based systems. One of ordinary skill in the art will recognize that the inherent flexibility of computer-based systems allows for a great variety of possible configurations, combinations, and divisions of tasks and

[0068] Referring now to the drawings in which is shown an example method 500 of operating a gas turbine engine in accordance with example aspects of the present disclosure. Figure 5 A flowchart of the method 500 of operating a gas turbine engine in accordance with example aspects of the present disclosure is provided. Figure 5 The method 500 can be used to operate the gear box system 202 described above with reference to Figures 1 to 4 The method 500 can be used to operate the gear box system 202 described above with reference to

[0069] As shown, the method 500 includes collecting operational data from a gas turbine engine at (502). As described above, the operational data can determine whether to increase the output of the gear box to improve operation of the gas turbine engine.

[0070] The method 500 includes identifying an operating condition of the gas turbine engine at (504). As described above, the operational data is indicative of a particular operation of the gas turbine engine, which can be classified as one of a plurality of operating conditions, such as takeoff, cruise, or landing. The controller can determine the operating condition based on particular values of the operational data.

[0071] The method 500 includes determining a specified temperature of the gear case at (506). Based on the operating conditions, a higher temperature gear case can have increased efficiency and can derive more power from the gear case. The controller can determine the specified temperature based on operating data used to identify the operating conditions.

[0072] The method 500 includes determining whether the current temperature of the gear case is below the specified temperature at (508). To determine the current temperature of the gear case, the controller collects data from one or more temperature sensors. The temperature sensors are located on components that directly or indirectly detect the temperature of the gear case. For example, one of the temperature sensors can be located on a metal portion of the gear case, such as a housing, flange, or ring gear. As another example, a temperature sensor can be located downstream of a coolant outlet of the gear case that detects the temperature of the coolant exiting the gear case. If the current temperature of the gear case is below the specified temperature, the method 500 continues to (510). Otherwise, the method 500 returns to (502).

[0073] The method 500 includes actuating one or more bypass valves to increase the temperature of the coolant entering the gear case at (510). The bypass valves direct the coolant heated by the gear case back to the inlet of the gear case. One of the bypass valves can direct the heated coolant from the outlet of the gear case to a location upstream of the inlet of the gear case, thereby increasing the temperature of the coolant entering the gear case. Another bypass valve can direct the heated coolant around a heat exchanger in which the coolant is cooled, to increase the temperature of the coolant entering the gear case.

[0074] Further aspects are provided by the subject matter of the following clauses:

[0075] A system for a gas turbine engine, the system comprising: a gearbox comprising a coolant inlet, a coolant outlet, and a metal portion; a first coolant supply line in fluid communication with the coolant inlet of the gearbox; a first temperature sensor in thermal communication with the first coolant supply line; a second coolant supply line in fluid communication with the coolant outlet of the gearbox; a second temperature sensor in thermal communication with the second coolant supply line; a third temperature sensor in thermal communication with the metal portion of the gearbox; a bypass line coupling the first coolant supply line to the second coolant supply line; a bypass valve disposed at a junction of the second coolant supply line and the bypass line; and a controller configured to actuate the bypass valve based on at least one of first temperature data from the first temperature sensor, second temperature data from the second temperature sensor, or third temperature data from the third temperature sensor.

[0076] The system of any preceding clause, further comprising a heat exchanger comprising an inlet and an outlet, wherein the second coolant supply line is in fluid communication with the inlet and the first coolant supply line is in fluid communication with the outlet.

[0077] The system of any preceding clause, further comprising a second bypass line connecting the second coolant supply line to the first coolant supply line, wherein the second bypass line has an inlet upstream of the inlet of the heat exchanger and an outlet downstream of the outlet of the heat exchanger.

[0078] The system of any preceding clause, further comprising a second bypass valve disposed in the second bypass line, wherein the controller is configured to actuate the second bypass valve based on at least one of the first temperature data, the second temperature data, or the third temperature data.

[0079] The system of any preceding clause, wherein the second bypass line is arranged to allow coolant to bypass a heat exchanger.

[0080] The system of any preceding clause, wherein the first temperature sensor is disposed between the outlet of the heat exchanger and the coolant inlet of the gearbox.

[0081] The system of any preceding clause, wherein the second temperature sensor is disposed between the coolant outlet of the gearbox and the inlet of the heat exchanger.

[0082] The system of any preceding clause, wherein the controller is further configured to actuate the bypass valve to increase a temperature of the coolant in the first coolant supply line.

[0083] The system of any preceding clause, wherein the controller is further configured to actuate the bypass valve to increase a temperature of the gear case based on a detected operating condition of the gas turbine engine.

[0084] The system of any preceding clause, wherein the controller is further configured to determine a temperature difference between the first temperature data and the second temperature data, and actuate the bypass valve when the temperature difference exceeds a threshold value.

[0085] The system of any preceding clause, wherein the controller is further configured to actuate the bypass valve when the third temperature data indicates that a temperature of the metal portion of the gear case is below a specified temperature.

[0086] The system of any preceding clause, wherein the controller is further configured to actuate the bypass valve to a specified duty cycle based on at least one of the first temperature data, the second temperature data, or the third temperature data.

[0087] The system of any preceding clause, further comprising a pump disposed upstream of the coolant inlet of the gear case.

[0088] The system of any preceding clause, wherein the metal portion of the gear case is a housing of the gear case.

[0089] The system of any preceding clause, wherein the operating condition is one of a plurality of operating conditions including takeoff, cruise, or landing.

[0090] The system of any preceding clause, wherein the controller is configured to collect operating data from the gas turbine engine, the operating data comprising at least one of: throttle position data, ambient air pressure data, altitude data, engine inlet temperature data, speed data, fuel temperature data, oil temperature data, and combinations thereof.

[0091] The system of any preceding clause, wherein the controller is configured to determine the operating condition based on a lookup table.

[0092] A system comprising a computer including a processor and a memory, the memory including instructions executable by the processor to: identify an operating condition of a gas turbine engine; collect temperature data from a temperature sensor in thermal communication with a gear case of the gas turbine engine; determine, based on the collected temperature data, whether a temperature of the gear case is below a specified temperature, the specified temperature based on the identified operating condition; and upon determining that the temperature of the gear case is below the specified temperature, actuate a bypass valve to direct coolant exiting a coolant outlet of the gear case to a coolant inlet of the gear case.

[0093] The system of any preceding clause, wherein the instructions further include instructions executable to determine a temperature difference between a first temperature of the coolant upstream of the coolant inlet and a second temperature of the coolant downstream of the coolant outlet and actuate the bypass valve based on the temperature difference.

[0094] The system of any preceding clause, the instructions further including instructions executable to actuate the bypass valve to a specified duty cycle based on at least one of the temperature of the gear case or the temperature difference.

[0095] The system of any preceding clause, the instructions further including instructions executable to actuate a second bypass valve to direct the coolant around a heat exchanger based on the temperature of the gear case.

[0096] The system of any preceding clause, wherein the temperature sensor is in thermal contact with a metal portion of the gear case.

[0097] The system of any preceding clause, wherein the instructions further include instructions executable to determine the specified temperature based on a specified efficiency target of the gear case.

[0098] The system of any preceding clause, the instructions further including instructions executable to: upon determining that the temperature of the gear case is above the specified temperature, determine whether the temperature of the gear case is below a second specified temperature, the second specified temperature greater than the specified temperature; and upon determining that the temperature of the gear case is above the second specified temperature, actuate the bypass valve to stop directing the coolant exiting the coolant outlet to the coolant inlet.

[0099] A method comprising: collecting operational data from a gas turbine engine; identifying an operating condition of the gas turbine engine; determining a specified temperature of a gearbox based on the identified operating condition; determining whether a current temperature of the gearbox is below the specified temperature; and actuating a bypass valve to increase coolant temperature upon determining that the current temperature of the gearbox is below the specified temperature.

[0100] The method of any preceding clause, wherein the operational data is indicative of a particular operation of the gas turbine engine, wherein the operating condition is one of a plurality of operating conditions including takeoff, cruise, or landing.

[0101] The method of any preceding clause, further comprising determining the temperature of the gearbox based on temperature data from a temperature sensor in thermal communication with a metal portion of the gearbox.

[0102] A method comprising: identifying an operating condition of a gas turbine engine; collecting temperature data from a temperature sensor in thermal communication with a gearbox of the gas turbine engine; determining, based on the collected temperature data, whether a temperature of the gearbox is below a specified temperature, the specified temperature based on the identified operating condition; and actuating a bypass valve to direct coolant exiting a coolant outlet of the gearbox to a coolant inlet of the gearbox upon determining that the temperature of the gearbox is below the specified temperature.

[0103] The method of any preceding clause, further comprising actuating the bypass valve to a specified duty cycle based on at least one of the temperature of the gearbox or the temperature difference.

[0104] The method of any preceding clause, further comprising actuating a second bypass valve to direct the coolant around a heat exchanger based on the temperature of the gearbox.

[0105] The method of any preceding clause, further comprising determining the specified temperature based on a specified efficiency target of the gearbox.

[0106] The method of any preceding clause, further comprising, upon determining that the temperature of the gearbox is above the specified temperature, determining whether the temperature of the gearbox is below a second specified temperature, the second specified temperature higher than the specified temperature; and actuating the bypass valve to stop directing the coolant exiting the coolant outlet to the coolant inlet upon determining that the temperature of the gearbox is above the second specified temperature.

[0107] This written description uses examples to disclose the disclosure, including the best mode, and also to enable any person skilled in the art to practice the disclosure, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and can include other examples that 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 do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A system for a gas turbine engine characterized by, The system comprises: a gearbox comprising a coolant inlet, a coolant outlet, and a metal portion; a first coolant supply line in fluid communication with the coolant inlet of the gearbox; a first temperature sensor in thermal communication with the first coolant supply line; a second coolant supply line in fluid communication with the coolant outlet of the gearbox; a second temperature sensor in thermal communication with the second coolant supply line; a third temperature sensor in thermal communication with the metal portion of the gearbox; a bypass line coupling the first coolant supply line to the second coolant supply line; a bypass valve disposed at a junction of the second coolant supply line and the bypass line; and a controller configured to actuate the bypass valve based on at least one of first temperature data from the first temperature sensor, second temperature data from the second temperature sensor, or third temperature data from the third temperature sensor.

2. The system of claim 1, wherein, further comprising a heat exchanger comprising an inlet and an outlet, wherein the second coolant supply line is in fluid communication with the inlet and the first coolant supply line is in fluid communication with the outlet.

3. The system of claim 2, wherein, further comprising a second bypass line connecting the second coolant supply line to the first coolant supply line, wherein the second bypass line has an inlet upstream of the inlet of the heat exchanger and an outlet downstream of the outlet of the heat exchanger.

4. The system of claim 3, wherein, further comprising a second bypass valve disposed in the second bypass line, wherein the controller is configured to actuate the second bypass valve based on at least one of the first temperature data, the second temperature data, or the third temperature data.

5. The system of claim 2, wherein, wherein the first temperature sensor is disposed between the outlet of the heat exchanger and the coolant inlet of the gearbox.

6. The system of claim 2, wherein, wherein the second temperature sensor is disposed between the coolant outlet of the gearbox and the inlet of the heat exchanger.

7. The system of claim 1, wherein, wherein the controller is further configured to actuate the bypass valve to increase a temperature of coolant in the first coolant supply line.

8. The system of claim 1, wherein, wherein the controller is further configured to actuate the bypass valve to increase a temperature of the gearbox based on a detected operating condition of the gas turbine engine.

9. The system of claim 1, wherein, wherein the controller is further configured to determine a temperature difference between the first temperature data and the second temperature data and actuate the bypass valve when the temperature difference exceeds a threshold value.

10. The system of claim 1, wherein, wherein the controller is further configured to actuate the bypass valve when the third temperature data indicates that a temperature of the metal portion of the gearbox is below a specified temperature.

Images