Patent Application
20130284398
This disclosure relates generally to a gas turbine engine, and more particularly to a gas turbine engine thermal management system that manages the heat generated by a gas turbine engine.
Gas turbine engines, such as turbofan gas turbine engines, generally include a fan section, a compressor section, a combustor section and a turbine section. During operation, airflow is pressurized in the compressor section and is mixed with fuel and burned in the combustor section. The hot combustion gases that are generated in the combustor section are communicated through the turbine section. The turbine section extracts energy from the hot combustion gases to power the compressor section, the fan section and other gas turbine engine loads.
A thermal management system can be employed within the gas turbine engine to manage the heat generated by the gas turbine engine. Thermal management systems maintain operable temperatures for the engine fuel, oil and other fluids that are communicated throughout the engine. For example, a portion of the heat of the engine oil can be transferred into the engine fuel to increase the efficiency of the gas turbine engine.
A thermal management system according to an exemplary aspect of the present disclosure includes, among other things, a first fluid circuit that selectively communicates a first portion of a first conditioned fluid having a first temperature to a first gas turbine engine system and a second portion of the first conditioned fluid having a second temperature to a second gas turbine engine system. The second temperature is a greater temperature than the first temperature. A second fluid circuit circulates a second conditioned fluid that is different from the first conditioned fluid to a third gas turbine engine system.
In a further non-limiting embodiment of the foregoing system, the first fluid circuit circulates oil and the second fluid circuit circulates fuel.
In a further non-limiting embodiment of either of the foregoing systems, the first gas turbine engine system is a first portion of a geared architecture of a fan section, the second gas turbine engine system is a second, different portion of the geared architecture, and the third gas turbine engine system is a combustor.
In a further non-limiting embodiment of any of the foregoing systems, the first fluid circuit incorporates a first heat exchanger, a second heat exchanger and a third heat exchanger and the second fluid circuit incorporates the second heat exchanger.
In a further non-limiting embodiment of any of the foregoing systems, a bypass passage extends between the first heat exchanger and the second engine system.
In a further non-limiting embodiment of any of the foregoing systems, a sensor senses a temperature of the second conditioned fluid, and a controller in communication with the sensor is operable to modulate a valve where the temperature of the second conditioned fluid exceeds a predefined threshold. A portion of the first conditioned fluid is communicated to the third heat exchanger only in response to the second conditioned fluid exceeding the predefined threshold.
In a further non-limiting embodiment of any of the foregoing systems, the first conditioned fluid is a mixed conditioned fluid that combines a second conditioned fluid and a third conditioned fluid from separate heat exchangers incorporated into the first fluid circuit.
In a further non-limiting embodiment of any of the foregoing systems, the first fluid circuit includes a first heat exchanger and a second heat exchanger. The first heat exchanger exchanges heat between the first conditioned fluid and the second conditioned fluid and the second heat exchanger exchanges heat between the first conditioned fluid and another fluid.
In a further non-limiting embodiment of any of the foregoing systems, the first fluid circuit includes a first heat exchanger, a second heat exchanger and a third heat exchanger. The first fluid circuit is configured so that a conditioned fluid exits the first heat exchanger, a first portion of the conditioned fluid from the first heat exchanger selectively enters the second heat exchanger and a second portion of the conditioned fluid from the first heat exchanger selectively enters the third heat exchanger.
In a further non-limiting embodiment of any of the foregoing systems, fluid exiting the second and third heat exchangers combine to form the first conditioned fluid.
A thermal management system according to an exemplary aspect of the present disclosure includes, among other things, a first fluid circuit that selectively communicates a first portion of a conditioned oil having a first temperature to a first portion of a geared architecture of a fan section of a gas turbine engine and a mixture including a second portion of the conditioned oil and the first portion of the conditioned oil or another fluid that includes a second temperature to a second, different portion of the geared architecture. The second temperature is a greater temperature than the first temperature. A second fluid circuit circulates a conditioned fuel to a combustor of the gas turbine engine. The conditioned fuel exchanges heat with the conditioned oil prior to communication to the combustor.
In a further non-limiting embodiment of the foregoing system, the mixture includes the second portion of the conditioned oil and the another fluid.
In a further non-limiting embodiment of either of the foregoing systems, the first fluid circuit includes a first heat exchanger, a second heat exchanger and a third heat exchanger. The first fluid circuit is configured so that a conditioned fluid exits the first heat exchanger, a first portion of the conditioned fluid from the first heat exchanger selectively enters the second heat exchanger and a second portion of the conditioned fluid from the first heat exchanger selectively enters the third heat exchanger.
In a further non-limiting embodiment of any of the foregoing systems, fluids exiting the second and third heat exchangers combine to form the conditioned oil.
In a further non-limiting embodiment of any of the foregoing systems, the second heat exchanger is incorporated into the second fluid circuit such that the first portion of the conditioned fluid from the first heat exchanger that enters the second heat exchanger exchanges heat with a fuel to provide the conditioned fuel.
The various features and advantages of this disclosure will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.
The gas turbine engine 20 generally includes a low speed spool 30 and a high speed spool 32 mounted for rotation about an engine centerline longitudinal axis A. The low speed spool 30 and the high speed spool 32 may be mounted relative to an engine static structure 33 via several bearing systems 31. It should be understood that other bearing systems 31 may alternatively or additionally be provided.
The low speed spool 30 generally includes an inner shaft 34 that interconnects a fan 36, a low pressure compressor 38 and a low pressure turbine 39. The inner shaft 34 can be connected to the fan 36 through a geared architecture 45 to drive the fan 36 at a lower speed than the low speed spool 30. The high speed spool 32 includes an outer shaft 35 that interconnects a high pressure compressor 37 and a high pressure turbine 40. In this embodiment, the inner shaft 34 and the outer shaft 35 are supported at various axial locations by bearing systems 31 positioned within the engine static structure 33.
A combustor 42 is arranged between the high pressure compressor 37 and the high pressure turbine 40. A mid-turbine frame 44 may be arranged generally between the high pressure turbine 40 and the low pressure turbine 39. The mid-turbine frame 44 can support one or more bearing systems 31 of the turbine section 28. The mid-turbine frame 44 may include one or more airfoils 46 that extend within the core flow path C.
The inner shaft 34 and the outer shaft 35 are concentric and rotate via the bearing systems 31 about the engine centerline longitudinal axis A, which is co-linear with their longitudinal axes. The core airflow of the core flow path C is compressed by the low pressure compressor 38 and the high pressure compressor 37, is mixed with fuel and burned in the combustor 42, and is then expanded over the high pressure turbine 40 and the low pressure turbine 39. The high pressure turbine 40 and the low pressure turbine 39 rotationally drive the respective high speed spool 32 and the low speed spool 30 in response to the expansion.
The pressure ratio of the low pressure turbine 39 can be pressure measured prior to the inlet of the low pressure turbine 39 as related to the pressure at the outlet of the low pressure turbine 39 and prior to an exhaust nozzle of the gas turbine engine 20. In one non-limiting embodiment, the bypass ratio of the gas turbine engine 20 is greater than about ten (10:1), the fan diameter is significantly larger than that of the low pressure compressor 38, and the low pressure turbine 39 has a pressure ratio that is greater than about five (5:1). It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines, including direct drive turbofans.
In this embodiment of the exemplary gas turbine engine 20, a significant amount of thrust is provided by the bypass flow path B due to the high bypass ratio. The fan section 22 of the gas turbine engine 20 is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet. This flight condition, with the gas turbine engine 20 at its best fuel consumption, is also known as bucket cruise Thrust Specific Fuel Consumption (TSFC). TSFC is an industry standard parameter of fuel consumption per unit of thrust.
Fan Pressure Ratio is the pressure ratio across a blade of the fan section 22 without the use of a Fan Exit Guide Vane system. The low Fan Pressure Ratio according to one non-limiting embodiment of the example gas turbine engine 20 is less than 1.45. Low Corrected Fan Tip Speed is the actual fan tip speed divided by an industry standard temperature correction of [(Tram° R.)/(518.7° R.)]0.5. The Low Corrected Fan Tip Speed according to one non-limiting embodiment of the example gas turbine engine 20 is less than about 1150 fps (351 m/s).
Each of the compressor section 24 and the turbine section 28 may include alternating rows of rotor assemblies and vane assemblies (shown schematically) that carry airfoils that extend into the core flow path C. For example, the rotor assemblies can carry a plurality of rotating blades 25, while each vane assembly can carry a plurality of vanes 27 that extend into the core flow path C. The blades 25 create or extract energy (in the form of pressure) from the core airflow that is communicated through the gas turbine engine 20 along the core flow path C. The vanes 27 direct the core airflow to the blades 25 to either add or extract energy.
Multiple sections of the gas turbine engine 20 generate heat during engine operation, including the fan section 22, the compressor section 24, the combustor section 26 and the turbine section 28. This heat may be carried by fluids that are communicated throughout these and other various sections of the gas turbine engine 20. For example, engine fuel and engine oil are circulated throughout the gas turbine engine 20 and carry a portion of the heat that is generated during engine operation. In this disclosure, the term “fluid” is intended to include fuel, oil, lubricating fluids, hydraulic fluids or any other fluids circulated through the gas turbine engine 20.
The thermal management system 100 is mounted to the gas turbine engine 20. The mounting location of the thermal management system 100 is application specific. Non-limiting example mounting locations for the thermal management system 100 include the engine static structure 33 (see
The thermal management system 100 includes a first fluid circuit 60 and a second fluid circuit 62. For example, the first fluid circuit 60 can circulate a first fluid 81, such as engine oil, and the second fluid circuit 62 can circulate a second fluid 87, such as engine fuel. It should be understood that other fluids in addition to oil and fuel are contemplated as within the scope of this disclosure. In combination, the first fluid circuit 60 and the second fluid circuit 62 transfer heat between the fluids communicated through the separate circuits 60, 62 to manage the temperatures of these fluids, as is further discussed below.
The first fluid circuit 60 incorporates a fluid tank 64, a first heat exchanger 66, a second heat exchanger 68, a third heat exchanger 70 and a pump 72. The pump 72 pumps a first fluid (indicated by arrow 81), such as oil, from the fluid tank 64 along a passage 74 to an inlet 76 of the first heat exchanger 66. Optionally, the first fluid circuit 60 can include a filter 78 for filtering the first fluid 81 prior to communicating the first fluid 81 to the inlet 76. Additionally, the first fluid circuit 60 can include a trim passage 80 for returning a portion of the first fluid 81 to the fluid tank 64 in the event an excess amount of the first fluid 81 is pumped from the fluid tank 64.
The first fluid 81 is communicated through the first heat exchanger 66 and exchanges heat with a different, third fluid 82, such as air, to condition the first fluid 81. In this example, the first heat exchanger 66 is an air/oil cooler that exchanges heat between oil and air. However, other types of heat exchangers can also be utilized. Heat from the first fluid 81 is transferred into the third fluid 82 to provide a first conditioned fluid 83 that exits an outlet 84 of the first heat exchanger 66.
The first conditioned fluid 83 is communicated along a passage 86 to a valve 88. The valve 88 controls the amount of the first conditioned fluid 83 that is communicated to the second heat exchanger 68 and the third heat exchanger 70. In one embodiment, the second heat exchanger 68 either receives an entirety of the first conditioned fluid 83 that is received by the valve 88, or receives only a portion thereof, as is further detailed below. In other words, the first and second heat exchangers 66, 68 are in continuous operation during operation of the thermal management system 100, but the third heat exchanger 70 is only selectively operated as required.
A first portion 85 of the first conditioned fluid 83 is communicated to an inlet 92 of the second heat exchanger 68 along a passage 90. The first portion 85 of the first conditioned fluid 83 is communicated through the second heat exchanger 68 and exchanges heat with the second fluid 87, such as fuel, that is circulated through the second fluid circuit 62. The second heat exchanger 68 renders a second conditioned fluid 89 which is communicated through an outlet 94 of the second heat exchanger 68 and into a passage 96.
To the extent the third heat exchanger 70 receives a portion of the first conditioned fluid 83 (discussed in greater detail below), a second portion 91 of the first conditioned fluid 83 can be communicated along a passage 98 to an inlet 102 of the third heat exchanger 70. The second portion 91 of the first conditioned fluid 83 is communicated through the third heat exchanger 70 and exchanges heat with yet another fluid 104, such as air, to render a third conditioned fluid 93 that exits the third heat exchanger 70 at outlet 106. The third conditioned fluid 93 from the third heat exchanger 70 is communicated along a passage 108 and is eventually communicated into the passage 96 such that the second conditioned fluid 89 from the second heat exchanger 68 and the third conditioned fluid 93 from the third heat exchanger 70 are mixed together to render a mixed conditioned fluid 95.
A first portion 97 of the mixed conditioned fluid 95 is communicated to a first engine system 110 along a passage 112. A second portion 99 of the mixed conditioned fluid 95 is communicated along passage 114 and is mixed with a third portion 101 of the first conditioned fluid 83 (communicated from the first heat exchanger 66 along a bypass passage 116 that extends between the first heat exchanger 66 and a second engine system 118) and is communicated to a second engine system 118. In this way, conditioned fluids having varying temperatures can be delivered to separate engine systems. For example, a mixture of the second portion 99 of the mixed conditioned fluid 95 and the third portion 101 of the first conditioned fluid 83 can include a greater temperature than the first portion 97 of the mixed conditioned fluid 95.
The first engine system 110 could include a portion of the geared architecture 48 of the fan section 22, such as journal bearings or other parts of the geared architecture 48. The second engine system 118 could include an engine bearing compartment, an engine gearbox or a drive mechanism of the geared architecture 48. Although only two engine systems are illustrated, it should be understood that additional or fewer engine systems can receive conditioned fluids from the thermal management system 100.
The second fluid circuit 62 of the thermal management system 100 includes a fluid tank 120, the second heat exchanger 68 (which is also incorporated into the first fluid circuit 60) and a pump 122. The second fluid circuit 62 can also optionally include a secondary pump 136.
The fluid tank 120 stores the second fluid 87 that is different from the first fluid 81 for use by the gas turbine engine 20. In one example, the second fluid 87 is fuel. The pump 122 pumps the second fluid 87 from the fluid tank 120 along a passage 124 and through the second heat exchanger 68 along a passage 126 to extract heat from the first portion 85 of the first conditioned fluid 83 that is communicated through the second heat exchanger 68 in the first fluid circuit 60. A conditioned second fluid 105 is delivered along a passage 128 to a portion of the gas turbine engine, such as the combustor section 26 for generating the hot combustion gases that flow to the turbine section 28. A portion 107 of the conditioned second fluid 105 can be returned to the passage 124 via a bypass passage 130.
The second fluid circuit 62 can also incorporate a sensor 132 (i.e., a first sensor), such as a temperature sensor or other suitable sensor. The sensor 132 monitors the temperature of the conditioned second fluid 105. The sensor 132 communicates with an engine controller 134. The engine controller 134 is programmed with the necessary logic to interpret the information from the sensor 132, among other information, and modulate a positioning of the valve 88. The position of the valve 88 establishes what amount, if any, of the first conditioned fluid 83 will be communicated to the second and third heat exchangers 68, 70. In other words, the position of the valve 88 controls the amount of heat added to the second fluid 87 at different engine power conditions. Other valves, sensors and controls, examples of which are described below, could also be incorporated into the thermal management system 100.
In one example, the third heat exchanger 70 receives a portion of the first conditioned fluid 83 only if a temperature of the conditioned second fluid 105 of the second fluid circuit 62 is above a predefined threshold. In one example, the pre-defined defined threshold is approximately 300° F./148.9° C., although the actual setting will depend on design specific parameters. If the sensor 132 alerts the engine controller 134 (via a signal, for example) that this predefined threshold has been exceeded, the engine controller 134 modulates the valve 88 to split a flow of the first conditioned fluid 83 between the second heat exchanger 68 and the third heat exchanger 70. Of course, other parameters can also be monitored and interpreted by the engine controller 134 in addition to the temperature from sensor 132, and other predefined thresholds can be set for controlling the valve 88. The actual amount of the first conditioned fluid 83 that is communicated to each of the second and third heat exchangers 68, 70 will vary depending upon the parameters monitored by the engine controller 134.
Although the different non-limiting embodiments are illustrated as having specific components, the embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting embodiments in combination with features or components from any of the other non-limiting embodiments.
It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed and illustrated in these exemplary embodiments, other arrangements could also benefit from the teachings of this disclosure.
The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For these reasons, the following claims should be studied to determine the true scope and content of this disclosure.
This application is a continuation of U.S. patent application Ser. No. 13/285,454, filed on Oct. 31, 2011.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13285454 | Oct 2011 | US |
| Child | 13926154 | US |
