Embedded motor cooling

Abstract

In one example embodiment, a gas turbine engine is provided. The gas turbine engine defines a radial, an axial, and an axial extension of the gas. The gas turbine engine includes a shaft configured to rotate about the axial, an electric machine including a rotor coupled to the shaft and rotatable with the shaft and a stator, the rotor defining an end in the axial, and a cooling manifold rotatable with the rotor and positioned at the end of the rotor, the cooling manifold configured to receive a flow of a cooling fluid during operation of the gas turbine engine and provide the cooling fluid to the stator.

Description

[0001] Related applications

[0002] This application claims priority from Polish patent application No. P.437703 filed on April 26, 2021. Technical Field

[0003] The present application generally relates to a cooling assembly for an embedded electric machine within a gas turbine engine. Background Art

[0004] Electric motors generate heat during operation. Therefore, even when installed in a cold section of an aircraft engine, it may be necessary to provide cooling for the electric motors. A system and method for cooling electric motors would be useful. Summary of the Invention

[0005] Aspects and advantages of the disclosure will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the disclosure.

[0006] In one exemplary embodiment, a gas turbine engine is provided. The gas turbine engine defines a radial axis, an axial axis, and an axis extending in the axial direction of a gas. The gas turbine engine includes: a shaft configured to rotate about the axis; an electric machine including a rotor and a stator, the rotor coupled to the shaft and rotatable therewith, the rotor defining an axial end; and a cooling manifold rotatable therewith and positioned at the end of the rotor, the cooling manifold configured to receive a flow of cooling fluid during operation of the gas turbine engine and to provide the cooling fluid to the stator.

[0007] These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various aspects of the present disclosure and, together with the description, serve to explain the principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A complete and enabling disclosure, including the best mode thereof, to one of ordinary skill in the art is set forth in the specification, which relates to the accompanying drawings, in which:

[0009] Figure 1 is a schematic cross-sectional view of a gas turbine engine according to an exemplary aspect of the present disclosure.

[0010] Figure 2 is a close-up schematic cross-sectional view of an electric machine according to an exemplary aspect of the present disclosure.

[0011] Figure 3 is a perspective view of a cooling manifold according to an exemplary aspect of the present disclosure.

[0012] Figure 4 is a first cross-sectional view of an exemplary cooling manifold of Figure 3

[0013] Figure 5 is a second cross-sectional view of an exemplary cooling manifold of Figure 3

[0014] Figure 6 is a cross-sectional view of a cooling manifold according to exemplary aspects of the present disclosure.

[0015] Figure 7 is a cross-sectional view of an exemplary cooling manifold of Figure 6

[0016] Figure 8 is a schematic view of a seal according to exemplary embodiments of the present disclosure. DETAILED DESCRIPTION

[0017] Reference will now be made in detail to the presently preferred embodiments of the application, 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 portions of the application.

[0018] The term "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.

[0019] As used herein, the terms "first," "second," and "third" can be used interchangeably to distinguish one component from another and are not necessarily intended to denote a position or importance of the individual components.

[0020] The terms "forward" and "aft" refer to relative positions within a gas turbine engine or vehicle and refer to the normal operating attitude of the gas turbine engine or vehicle. For example, with respect to a gas turbine engine, forward refers to a position closer to the engine inlet and aft refers to a position closer to the engine nozzle or exhaust.

[0021] The terms "upstream" and "downstream" refer to the relative direction with respect to fluid flow in a fluid pathway. For example, "upstream" refers to a direction against the flow of fluid, and "downstream" refers to a direction with the flow of fluid.

[0022] The terms "coupled," "fixed," "attached," and the like, mean to be directly or indirectly connected or attached by one or more intermediate parts or features, unless otherwise specified herein.

[0023] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. ​​​

[0024] Approximating language, as used in this specification and claims, is intended to modify any quantitative representation that can permissibly vary without resulting in a change in the basic function to which it is related. Thus, a value modified by one or more terms, such as "about," "approximately," and "substantially," is not limited to the precise value specified. In at least some instances, approximating language may correspond to the precision of an instrument used to measure the value, or the precision of a method or machine used to construct or manufacture a component and / or system. For example, approximating language may refer to within a margin of 1, 2, 4, 10, 15, or 20%.

[0025] Here and throughout the specification and claims, range limitations are combined and interchangeable, and these ranges are identified and include all sub-ranges contained therein unless context or language indicates otherwise. For example, all ranges disclosed herein include the endpoints, and the endpoints are independently combinable with each other.

[0026] Now referring to the accompanying drawings, Figure 1 A front cross-sectional view of an exemplary embodiment of a gas turbine engine is shown, which may incorporate one or more inventive aspects of the present disclosure. In particular, Figure 1 The exemplary gas turbine engine of FIG. 1 is configured as a single, unducted rotor engine 10 that defines an axial direction A, a radial direction R, and a circumferential direction C (extending about the axial direction A). Figure 1 As can be seen, engine 10 takes the form of an open rotor propulsion system and has a rotor assembly 12 that includes an array of airfoils, and more specifically, an array of rotor blades 16, arranged about a central longitudinal axis 14 of engine 10. Furthermore, as will be explained in greater detail below, engine 10 also includes a non-rotating bucket assembly 18 positioned aft of rotor assembly 12 (i.e., non-rotating relative to central axis 14) that includes an array of airfoils, and more specifically, an array of buckets 20, also arranged about central axis 14. Rotor blades 16 may be arranged in a generally equidistantly spaced relationship about centerline 14. Rotor assembly 12 further includes a hub 45 located forward of the plurality of rotor blades 16.

[0027] Still refer to Figure 1 , the bucket assembly 18 extends from the fairing 48 and is positioned rearwardly of the rotor assembly 12. The buckets 20 of the bucket assembly 18 may be mounted to a stationary frame or other mounting structure and do not rotate relative to the central axis 14. For reference purposes, Figure 1 The forward direction is also depicted by arrow F, which in turn defines the front and rear portions of the system. Figure 1 As shown, rotor assembly 12 is located at the front end of engine 10 in a "trailing" configuration.

[0028] Additionally, the engine 10 includes a turbomachine 30 having a core 32 (or high speed system) and a low speed system. The core 32 generally includes a high speed compressor 34, a high speed turbine 36, and a high speed shaft 38 extending between and connecting the high speed compressor 34 and the high speed turbine 36. The high speed compressor 34, the high speed turbine 36, and the high speed shaft 38 can be collectively referred to as a high speed spool of the engine. Moreover, a combustion section 40 is located between the high speed compressor 34 and the high speed turbine 36. The combustion section 40 can include one or more configurations for receiving a mixture of fuel and gas and providing a flow of combustion gases through the high speed turbine 36 for driving the high speed spool.

[0029] The low speed system similarly includes a low speed turbine 42, a low speed compressor or booster 44, and a low speed shaft 46 extending between and connecting the low speed compressor 44 and the low speed turbine 42. The low speed compressor 44, the low speed turbine 42, and the low speed shaft 46 can be collectively referred to as a low speed spool of the engine.

[0030] Although the engine 10 is depicted as having the low speed compressor 44 positioned forward of the high speed compressor 34, in certain embodiments, the compressors 34, 44 can be in a cross- arrangement. Additionally or alternatively, although the engine 10 is depicted as having the high speed turbine 36 positioned forward of the low speed turbine 42, in certain embodiments, the turbines 36, 42 can similarly be in a cross- arrangement.

[0031] Still referring to Figure 1 The turbomachine 30 is generally enclosed in a nacelle 48. Moreover, it should be appreciated that the nacelle 48 at least partially defines an inlet 50 and an exhaust 52, and includes a turbomachine flow path 54 extending between the inlet 50 and the exhaust 52. For the illustrated embodiment, the inlet 50 is an annular or axisymmetric 360 degree inlet 50 located between the rotor blade assembly 12 and the fixed or stationary vane assembly 18, and provides a path for the atmosphere to enter the turbomachine flow path 54 (and the compressors 44, 34, the combustion section 40, and the turbines 36, 42) along the radially inner side of the guide vanes 20.

[0032] However, in other embodiments, the inlet 50 can be positioned at any other suitable location, e.g., aft of the vane assembly 18, arranged in a non-axisymmetric manner, etc.

[0033] As shown, the rotor assembly 12 is driven by the turbomachine 30, and more particularly, by the low speed shaft 46. More particularly, still referring to Figure 1The exemplary embodiment of the engine 10 shown, the engine 10 includes a power gear box 56 and a rotor assembly 12 driven by the low speed shaft 46 of the turbine 30 through the power gear box 56. In this manner, the rotating rotor blades 16 of the rotor assembly 12 can rotate about the axis 14 and generate thrust to propel the engine 10, and thus an aircraft associated therewith, in the forward direction F.

[0034] The power gear box 56 can include a gear set for reducing the rotational speed of the low speed shaft 46 relative to the low speed turbine 42 such that the rotor assembly 12 can rotate at a slower rotational speed than the low speed shaft 46.

[0035] Further, for the embodiment shown, the engine 10 includes an electric machine 62 coupled to a shaft of the engine rotatable about the longitudinal axis 14 of the engine 10 and radially inward of the engine flow path 54 and radially inward of the airflow through the rotor blades 16 of the rotor assembly 12. More specifically, for the embodiment shown, it should be appreciated that the engine 10 includes a rotor shaft 64 extending from the gear box 56 to the rotor blades 16 of the rotor assembly 12 for driving the rotor blades 16 of the rotor assembly 12. For the embodiment shown, the electric machine 62 is coupled to and rotatable with the rotor shaft 64.

[0036] As will be described in greater detail below, the engine 10 includes a cooling system for maintaining the temperature of the electric machine 62 within prescribed temperature limits. The cooling system generally includes a liquid cooling system 66 in thermal communication with the electric machine 62 to cool the electric machine 62 as well as a cooling air system 68. The cooling air system 68 can receive airflow from the engine flow path 54 at a location downstream of the inlet 50 through one or more ducts 70 and a valve 72. The inlet of the duct 70 can include features (e.g., one or more louvers, scoops, slots, etc.) to direct the flow through the duct 70 based on, for example, the amount of cooling flow needed, the amount of turning pressure recovery desired (e.g., to ensure that the cooling air system 68 is properly pressurized), etc. The duct 70 can also extend through the engine flow path 54 at a location downstream of an inlet guide vane 74 and upstream of the low speed compressor 44 to the electric machine 62. However, in other embodiments, the duct 70 of the cooling air system 68 can extend through the engine flow path 54 at any other suitable location or can provide any other suitable form of cooling airflow to the electric machine 62.

[0037] However, it should be appreciated that, Figure 1The exemplary single-spool, ductless engine 10 depicted in FIG. 1 is provided as an example only, and in other exemplary embodiments, the engine 10 may have any other suitable configuration, including, for example, any other suitable number of shafts or spools, turbines, compressors, etc. Furthermore, while the engine 10 is depicted as a single, ductless rotor engine 10, in other embodiments, the engine 10 may further include a nacelle or duct surrounding at least a portion of the rotor assembly 12, the turbine, or both. In such a configuration, the outlet guide vanes may be connected to the nacelle, and the nacelle and turbine may together define a bypass passage. Additionally or alternatively, while the engine 10 is depicted as a geared engine 10 (i.e., including a gearbox between the low-speed shaft 46 and the rotor assembly 12), in other embodiments, aspects of the present disclosure may additionally or alternatively be applied to a direct-drive engine, wherein the low-speed shaft 46 and the rotor shaft 64 of the rotor assembly are connected or coordinated such that the low-speed shaft rotates at the same speed as the rotor assembly 12.

[0038] Further, although engine 10 is described as having a rotor assembly with a single stage of rotor blades, in other embodiments, engine 10 may include a multi-stage rotor configuration (open or enclosed by a nacelle), and aspects of the disclosure described below may be incorporated therein.

[0039] Furthermore, in still other exemplary embodiments, any other suitable gas turbine engine 10 may be provided. For example, in other exemplary embodiments, the gas turbine engine 10 may be a ducted turbofan engine 10, a turboshaft engine, a turboprop engine, a turbojet engine, or the like.

[0040] Now refer to Figure 2 , which depicts a close-up schematic diagram of the motor 62 coupled to and rotating with the engine shaft 80 of the engine 10, which is rotatable about the axis 14 of the engine 10. In certain exemplary embodiments, Figure 2 The motor 62 and engine 10 depicted in FIG. 1 may be used in conjunction with the motor 62 and engine 10 described above. Figure 1 The exemplary motor 62 in the engine 10 described above is configured in a similar manner, and thus, like or similar reference numerals may refer to like or similar parts. In this manner, it should be understood that in at least some exemplary embodiments, Figure 2 The engine shaft 80 depicted in FIG. 8 may be Figure 1 An exemplary rotor shaft 64 of engine 10 is shown, configured to rotate the plurality of rotor blades 16 of rotor assembly 12 about axis 14 .

[0041] However, in other embodiments, aspects of the present disclosure can be applied to other motor 62 mounting locations and / or engine configurations such that the engine shaft 80 can be any other suitable engine shaft (e.g., a low pressure shaft, a high pressure shaft, etc.).

[0042] For the depicted embodiment, the motor 62 generally includes a rotor 82 and a stator 84, the rotor 82 being coupled to and rotating with the engine shaft 80. More specifically, for the depicted embodiment, the rotor 82 is coupled to and rotates with the engine shaft 80 via a rotor mount 86. For the depicted embodiment, the rotor mount 86 extends from the engine shaft 80 to the rotor 82 to couple the rotor 82 of the motor 62 to the engine shaft 80.

[0043] The motor 62 is generally configured as a radial flux motor, defining an air gap 88 between the rotor 82 and the stator 84, the air gap 88 extending generally along the axial direction A of the engine 10. Moreover, for the depicted embodiment, the motor 62 is configured as an "in-runner" motor 62 such that the rotor 82 is located radially inward of the stator 84 along the radial direction R of the engine 10. Notably, however, in other embodiments, the motor 62 can have other suitable configurations. For example, in other embodiments, the motor 62 can optionally be oriented such that the air gap 88 defines an angle relative to the axial direction A of the engine 10.

[0044] As shown, for the depicted embodiment, the rotor 82 generally extends along the axial direction A, defining a first end 90 and a second end 92 along the axial direction A. Similarly, the stator 84 generally extends along the axial direction A, defining a first end 94 and a second end 96 along the axial direction A. More specifically, the stator 84 includes a core 98 and a plurality of windings 100, and for the depicted embodiment, the plurality of windings 100 include portions at the first end 94 and the second end 96 of the stator 84. It should be appreciated, however, that in other exemplary aspects, any other suitable stator configuration can be provided such that the first end and the second end 96 of the stator include any other suitable features.

[0045] As described above with reference to the embodiments described above, Figure 1 As described above with reference to the embodiments described above, Figure 2 The exemplary engine 10 depicted in the figures includes a cooling system for maintaining the temperature of the motor 62 within prescribed limits. The cooling system includes a liquid cooling system 64 that is thermally coupled to the motor 62. The liquid cooling system 64 can more specifically operate with the stator 84 to reduce the temperature of certain aspects of the stator 84.

[0046] However, the liquid cooling system 64 can have difficulty effectively reducing the temperature of other aspects of the stator 84 of the electric machine 62, such as the first end 94 and the second end 96 of the stator 84, such as portions of the windings 100 located at the first end 94 and the second end 96 of the stator 84. Thus, for the depicted embodiment, the cooling air system 68 provided can assist in cooling one or more of such portions of the electric machine 62.

[0047] As with the above-described embodiments, Figure 2 The exemplary cooling air system 68 of the engine 10 depicted includes one or more cooling ducts 70 for providing a flow of cooling fluid toward the electric machine 62 during operation of the engine 10. The one or more ducts 70 can more particularly provide a flow of cooling air 102 toward the electric machine 62 during operation of the engine 10. For example, in certain exemplary aspects, the one or more cooling ducts 70 can receive the flow of cooling air 102 as a flow of discharge air from the compressor section of the engine 10 from the compressor section of the engine 10. For example, the flow of discharge air can be provided from the low pressure compressor, from the high pressure compressor, and / or from a location between the low pressure compressor and the high pressure compressor. Alternatively, the flow of cooling air 102 in the duct 70 can be provided from, for example, an ambient location, a location on the cowling 48 of the engine 10.

[0048] Still referring to Figure 2 Generally, the one or more cooling ducts 70 of the cooling air system 68 provide a flow of cooling air 102 to cool various portions of the electric machine 62. In particular, for the exemplary embodiment shown, the one or more cooling ducts 70 of the cooling air system 68 define a first cooling air flow path 104 extending to a first end (e.g., end 90, 94) of the electric machine 62 and a second cooling air flow path 106 extending to a second end (e.g., end 92, 96) of the electric machine 62. The first cooling air flow path 104 and the second cooling air flow path 106 are separated at a junction 108 within the one or more ducts 70. It will be appreciated that the one or more ducts 70 can include one duct 70 or a plurality of ducts 70 positioned circumferentially. In this manner, the junction 108 can be a single junction or can be a plurality of junctions 108 at different locations circumferentially.

[0049] The first cooling air flow path 104 travels through a first opening 110 defined within one or more of the ducts 70 to a plenum 112 defined at least in part by a rotating rotor mount 86 extending between the engine shaft 80 in the rotor 82 and the stationary structure including the ducts 70. The first cooling air flow path 104 further travels through one or more openings 114 within the rotor mount 86 to a cooling manifold 116, which is rotatable with the rotor 82 and positioned at the first end 90 of the rotor 82. The cooling manifold 116 is configured to receive a flow of cooling fluid, and more particularly is configured to provide such cooling fluid to the stator 84 during operation of the engine 10. More particularly, still, for the illustrated embodiment, the flow of cooling fluid is the flow of cooling air 102 provided along the first cooling air flow path 104.

[0050] Briefly, it should be further understood that the second cooling air flow path 106 travels from the junction 108 to a stationary manifold 117 located at the second end 92 of the rotor 82 at a location inward of the second end 96 of the stator 84. The stationary manifold 117 can extend circumferentially with a generally annular chamber 119. A flow control feature 176 can be included, for example, at a location upstream of the stationary manifold 117 to control the amount of air flow 102 to the annular chamber 119. The flow control feature 176 can, for example, be a baffle or slot to drive flow into the annular chamber 119, increasing the heat transfer coefficient in the chamber 119 to provide additional cooling to the fluid seal 144 (described below). The flow control feature 176 can be sized to provide a deterministic heat transfer cooling to the fluid seal prior to delivering the flow through the stationary manifold 117 to the upper cavity. The stationary manifold 117 defines one or more second openings 118 oriented toward the second end 96 of the stator 84 of the electric machine 62. In this manner, the flow of cooling air 102 through the second cooling air flow path 106 can be provided onto the second end 96 of the stator 84, or more particularly onto a portion of the windings 100 of the stator 84 located at the second end 96 of the stator 84. The second air flow path 106 further extends across the air gap 88 of the electric machine 62 defined between the rotor 82 and the stator 84 such that the flow of cooling air 102 through the second air flow path 106 can further provide cooling to the electric machine 62 along the air gap 88.

[0051] Still referring to Figure 2Now returning to the cooling manifold 116, it should be noted that for the illustrated embodiment, the cooling manifold 116 is coupled to the first end 90 of the rotor 82 of the electric machine 62, to the rotor mount 86 (which couples the rotor 82 of the electric machine 62 to the engine shaft 80), or both. For the illustrated embodiment, the cooling manifold 116 is coupled to both the rotor 82 and the rotor mount 86. However, in other embodiments, the cooling manifold 116 can be coupled to only the rotor 82 or to only the rotor mount 86.

[0052] More specifically, reference is now made to Figure 3 , a perspective cross-sectional view of the cooling manifold 116 and Figure 2 a portion of the electric machine 62. From Figure 3 the view, it can be appreciated that for any of the illustrated embodiments, the cooling manifold 116 is coupled to the rotor mount 86 and the rotor 82 using a plurality of fasteners 120 spaced along the circumferential direction C of the engine 10. More specifically, again, for the illustrated embodiment, the cooling manifold 116 is coupled to the rotor mount 86 at a first location 122 along the radial direction R and at a second location 124 along the radial direction R using a plurality of fasteners 120 spaced along the circumferential direction C at each of the first and second locations 122, 124 along the radial direction R. Although for the illustrated embodiment, the cooling manifold 116 is not directly coupled to the rotor 82 of the electric machine 62, it should be appreciated that the cooling manifold 116 is positioned along the radial direction R adjacent to the first end 90 of the rotor 82 of the electric machine 62 and in the illustrated embodiment, directly contacts the rotor 82 of the electric machine 62. Additionally, as will be further discussed herein below, the cooling manifold 116 is positioned along the radial direction R inward of the second end 94 of the stator 84 (at the same location or an overlapping location along the axial direction A).

[0053] From the view of Figure 3 , it can also be appreciated that the cooling manifold 116 is configured as a generally annular manifold defining a generally annular airflow chamber 126 configured to receive the flow of cooling air 102 from the first air flow path 104 of the cooling air system 68. Referring to Figure 4 and Figure 5 simplified cross-sectional views, it should be appreciated that the cooling manifold 116 defines a plurality of protrusions 128 extending inwardly along the axial direction A to allow the cooling manifold 116 to be coupled to the rotor 82 at the second location 124 along the radial direction R using the plurality of fasteners 120. More specifically, Figure 4 illustrates a cross-sectional view of the cooling manifold 116 at one of these protrusions 128, and Figure 5 provides cross-sectional views of the cooling manifold 116 between the protrusions 128 at different circumferential locations. As Figure 5As shown, the cooling manifold 116 defines a clear flow path between the opening 114 in the rotor mount 86 and the generally annular airflow chamber 126 of the cooling manifold 116 (despite the presence of the protrusion 128).

[0054] Still generally referring to Figures 3 to 5 It should be appreciated that the cooling manifold 116 further defines one or more impingement openings 130 oriented radially R outwardly. More specifically, the cooling manifold 116 defines one or more impingement openings 130 oriented toward the stator 84 for providing the cooling airflow 102 received by the cooling manifold 116 within the generally annular airflow chamber 126 onto the stator 84. The one or more impingement openings 130 can include a plurality of impingement openings 130 spaced apart along a circumferential C of the engine 10. Alternatively, the one or more impingement openings 130 can include a continuous or generally continuous impingement opening 130 extending along the circumferential C.

[0055] Referring especially to Figure 3 It should be appreciated that, for the depicted embodiment, the one or more impingement openings 130 of the cooling manifold 116 are oriented toward the first end 94 of the stator 84 for providing the cooling airflow 102 received by the cooling manifold 116 within the generally annular airflow chamber 126 onto the first end 94 of the stator 84. More specifically, for the depicted embodiment, the one or more impingement openings 130 of the cooling manifold 116 are oriented toward at least a portion of the plurality of windings 100 of the stator 84 located at the first end 94 of the stator 84 for providing the cooling airflow 102 received by the cooling manifold 116 within the generally annular airflow chamber 126 onto the portion of the plurality of windings 100 located at the first end 94 of the stator 84.

[0056] It should be appreciated, however, that in other example embodiments of the present disclosure, the cooling air system 68 can have any other suitable configuration. For example, the cooling air manifold 116 can have any other suitable configuration. For example, the manifold 116 can define one or more impingement openings 130 oriented radially R outwardly in any other suitable manner, such as not directly radially R.

[0057] Referring briefly now to Figure 6 A cooling manifold 116 according to another example embodiment of the present application is provided. The depicted example cooling manifold 116 includes a partial thickness 168 defining one or more impingement openings 130. The inclusion of the partial thickness 168, which can have a maximum thickness that is at least twice the thickness of a surrounding portion of the cooling manifold 116, and up to 100 times the thickness of a surrounding portion of the cooling manifold 116, can allow the impingement openings 130 to direct the cooling air 102 in a more precise manner.

[0058] For example, referring now to Figure 7 , there is provided Figure 6 , one or more impingement openings 130 along Figure 6 , a schematic cross-sectional view along line 7-7 in Figure 7 , it should be appreciated that the example impingement openings 130 depicted in

[0059] According to one or more of these example embodiments, the inclusion of the cooling manifold 116 can allow the cooling air system 68 of the engine 10 to provide a desired amount of cooling to portions of the plurality of windings 100 that are positioned at the first end 94 of the stator 84.

[0060] Referring now back to Figure 2 , it should be appreciated that Figure 2 , the example engine 10 depicted in

[0061] Referring now also to Figure 8 , there is provided a close-up sectional view of the fluid seal 132. As shown, the fluid seal 132 generally includes a first member 134 that is rotatable with the rotor 82 of the electric machine 62 and a second member 136 that is coupled to or integrally formed with a static structure, such as one or more ducts 70 of the cooling air system 68 or a circumferential manifold that defines the opening 118 (seeFigure 2 The first member 134 generally includes a first set 138 of seal teeth 140 , and the second member 136 generally includes a second set 142 of seal teeth 144 , with the first and second sets 138 , 142 of seal teeth 140 , 144 alternately spaced along the length L of the fluid seal 132 .

[0062] More specifically, for the illustrated embodiment, the first set 138 of seal teeth 140 includes at least three seal teeth 140, and the second set 142 of seal teeth 144 also includes at least three seal teeth 144. More specifically, for the illustrated embodiment, the first set 138 of seal teeth 140 includes five seal teeth 140, and the second set 142 of seal teeth 144 includes four seal teeth 144. It should be understood that each seal tooth 140, 144 is generally oriented about the axis 14 of the engine 10 (see FIG. 1 ). Figure 2 ) annular seal teeth 140 extending 360° in the circumferential direction C. Although, for the illustrated embodiment, the first group 138 of seal teeth 140 includes five seal teeth 140 and the second group 142 of seal teeth 144 includes four seal teeth 140, in other embodiments, the first group 138 of seal teeth 140, the second group 142 of seal teeth 144, or both may have any other suitable number of seal teeth 140 within their respective groups. For example, in another exemplary embodiment, the first group 138 of seal teeth 140, the second group 142 of seal teeth 144, or both may include 1 seal tooth, 2 seal teeth, 3 seal teeth, 4 seal teeth, 5 seal teeth, 6 seal teeth, 7 seal teeth, 8 seal teeth, 9 seal teeth, 10 seal teeth, or up to 30 seal teeth. The first set 138 of seal teeth 140 may include the same number of seal teeth 144 as the second set 142 , or, alternatively, the first set 138 of seal teeth 140 and the second set 142 of seal teeth 144 may include different numbers of seal teeth 140 .

[0063] Further, for the illustrated embodiment, each seal tooth 140 within the first set 138 of seal teeth 140 and the second set 142 of seal teeth 144 extends generally in a direction perpendicular to the length L of the fluid seal 132. More specifically, for the illustrated embodiment, the length L of the fluid seal 132 is generally aligned with and defined along a radial direction R of the engine 10. In this manner, it should be understood that the first set 138 of seal teeth 140 and the second set 142 of seal teeth 144 extend generally in the axial direction A of the engine 10.

[0064] It should be appreciated, however, that in other example embodiments, the fluid seal 132 can be oriented in any other suitable direction (e.g., defining an angle relative to the radial direction R of the engine 10), and / or the plurality of sealing teeth 140 of the first set 138 and the plurality of sealing teeth 144 of the second set 142 can not extend directly perpendicular to the length L of the fluid seal 132.

[0065] Still referring to Figure 8 It should be appreciated that the first member 134 of the fluid seal 132 further defines a first plurality of valleys 148 between adjacent sealing teeth 140 of the first set 138, and similarly, the second member 136 defines a second plurality of valleys 150 between adjacent sealing teeth 144 of the second set 142. In the illustrated embodiment, the sealing teeth 140 of the first set 138 define a gap 152A with the second plurality of valleys 150 along the axial direction A, and similarly, the sealing teeth 144 of the second set 142 define a gap 154 with the first plurality of valleys 148 along the axial direction A. This configuration can allow for any natural changes between the rotor 82 of the electric machine 62 and the static structure surrounding the rotor 82 of the electric machine 62 along the axial direction A during operation of the engine 10.

[0066] Further, to further accommodate these natural changes, it should be appreciated that the first member 134 further includes a wear-resistant coating 156 on the first plurality of valleys 148 defined between adjacent sealing teeth 140 of the first set 138, and similarly, the second member 136 further includes a wear-resistant coating 158 on the second plurality of valleys 150 defined between adjacent sealing teeth 144 of the second set 142. The wear-resistant coatings 156, 158 are positioned on the surfaces of the valleys 148, 150 to interfere with the opposing sealing teeth 140, 144. In this manner, in the event that the relative motion between the rotor 82 of the electric machine 62 and the static structure surrounding the rotor 82 of the electric machine 62 exceeds the length of the gaps 152, 154, the respective sealing teeth 140 can not cause unnecessary damage to the first member 134, the second member 136, or both, and further can not substantially interrupt, for example, operation of the electric machine 62.

[0067] Notably, while not depicted, it should be appreciated that in at least certain example aspects, the sides of the teeth 140, 144 can also include a wear-resistant coating to accommodate, for example, relative motion along the radial direction R.

[0068] Still referring to Figure 2It should be appreciated that in certain example embodiments, the cooling air flow 102 from the cooling air system 68 can additionally provide further benefits and perform additional functions for the engine 10. For example, for the illustrated embodiment, the cooling air system 68 further defines a third cooling air flow path 160 branching from the first cooling air flow path 104 to provide the cooling air flow 102 / pressurized air flow to a sump. More specifically, the engine 10 defines a bearing sump 162 that encircles a bearing 164 that supports rotation of the engine shaft 80. In addition, the engine 10 includes a seal 166 (which is schematically represented and can be, for example, a labyrinth seal) that at least partially defines the bearing sump 162 around the bearing 164. The cooling air flow 102 through the second cooling air flow path 160 can pressurize the bearing sump 162 by providing pressurized air to the seal 166 and can also provide a cooling measure by providing any cooling 102 to the bearing sump 162.

[0069] Further, as Figure 2 schematically depicted, after taking the cooling measure, the cooling air flow 102 from the first cooling air flow path 104, the second cooling air flow path 106, and / or the third cooling air flow path 160 (or at least a portion of the cooling air flow 102 from the third cooling air flow path 160) can be provided to the engine flow path 54 of the engine 10. For example, the cooling air flow 102 through the first cooling air flow path 104 and the second cooling air flow path 106 can be provided to the engine flow path 54 after being provided to / impinging on the stator 84 of the electric machine 62. For example, in the illustrated embodiment, the cooling air flow 102 is provided to the engine fluid path 54 at a location upstream of a compressor of the engine 10 (see also, for example, FIG. 1) and more specifically at a location upstream of the inlet guide vane 74 of the engine 10. In particular, for the illustrated embodiment, the cooling air flow 102 is provided to the engine flow path 54 at a location represented by the arrow where the cooling air flow (labeled 102) reaches the flow path 54. Figure 1

[0070] In this manner, the cooling air flow 102 provided by the cooling air system 68 can be used to reduce the temperature of one or more example aspects of the electric machine 62 and / or other components of the engine 10, and can then provide energy to the engine flow path 54, increasing the amount of energy and airflow through the engine flow path 54.

[0071] Finally, still referring to Figure 2 ​It will be appreciated that at least certain components operable with and / or proximate to the electric machine 62 can be formed of a material configured to reduce the risk of electrical loss due to these components. For example, in at least certain example embodiments, the cooling manifold 116, the first member 134 of the fluid seal 132, the second member 136 of the fluid seal 132, and / or the circumferential manifold defining the opening 118 can be formed of a material configured to reduce the risk of electrical loss. More particularly, in certain example embodiments, the material can be a material having a relatively low electrical conductivity, such as a plastic material, a composite material, and / or the like.

[0072] Further aspects of the application are provided by the subject matter of the following clauses:

[0073] A gas turbine engine defining a radial, an axial, and an axial extension of the gas, the gas turbine engine comprising: a shaft configured to rotate about the axial; an electric machine comprising a rotor and a stator, the rotor coupled to the shaft and rotatable therewith, the rotor defining an end portion in the axial; and a cooling manifold rotatable with the rotor and positioned at the end portion of the rotor, the cooling manifold configured to receive a flow of cooling fluid during operation of the gas turbine engine and provide the cooling fluid to the stator.

[0074] The engine according to one or more of the clauses, wherein the gas turbine engine comprises a rotor assembly, and wherein the shaft is a rotor shaft for driving the unshrouded rotor assembly.

[0075] The engine according to one or more of the clauses, wherein the gas turbine engine comprises a compressor, and wherein the cooling fluid is a bleed air flow from the compressor.

[0076] The engine according to one or more of the clauses, wherein the cooling manifold is coupled to the end portion of the rotor of the electric machine, and wherein the end portion of the rotor is optionally at least partially positioned radially inward of the stator.

[0077] The engine according to one or more of the clauses, wherein the cooling manifold is coupled to the end portion of the rotor of the electric machine, to a rotor mount coupling the rotor to the engine shaft, or both.

[0078] The engine according to one or more of the clauses, wherein the rotor mount defines one or more openings for providing the flow of cooling fluid to the cooling manifold.

[0079] The engine according to one or more of the clauses, further comprising a rotor mount extending between the shaft and the rotor, and wherein the cooling manifold is coupled to the rotor mount.

[0080] An engine according to one or more of the clauses, wherein the cooling manifold defines one or more impingement openings oriented toward the stator for providing the cooling fluid as an impingement airflow onto the stator.

[0081] An engine according to one or more of the clauses, wherein the stator includes a plurality of windings, and wherein the one or more impingement openings are oriented toward at least a portion of the plurality of windings of the stator for providing the cooling fluid as an impingement airflow onto the plurality of windings of the stator.

[0082] An engine according to one or more of the clauses, wherein the manifold is a substantially annular manifold.

[0083] An engine according to one or more of the clauses, further comprising a liquid cooling system, wherein the liquid cooling system is in thermal communication with the electric machine to cool the electric machine.

[0084] An engine according to one or more of the clauses, further comprising: a bearing supporting rotation of the shaft; and a seal at least partially defining a bearing sump about the bearing; and a cooling airflow supply, wherein the cooling airflow supply is in airflow communication with the cooling manifold to provide a flow of cooling fluid to the cooling manifold and in airflow communication with the seal to pressurize the seal.

[0085] An engine according to one or more of the clauses, wherein the engine is a single ductless-rotor engine.

[0086] An engine according to one or more of the clauses, wherein the engine is any one of: a ducted turbofan engine, a ductless turbofan engine, a turboprop engine, a turboshaft engine, or a turbojet engine.

[0087] An engine according to one or more of the clauses, wherein the gas turbine engine defines an engine flow path, and wherein the cooling fluid is provided to the engine flow path after being provided onto the stator of the electric machine.

[0088] An engine according to one or more of the clauses, wherein the gas turbine engine includes a compressor, and wherein the cooling fluid is provided to the engine flow path at a location upstream of the compressor after being provided onto the stator of the electric machine.

[0089] An engine according to one or more of the clauses, wherein the gas turbine engine includes an inlet guide vane, and wherein the cooling fluid is provided to the engine flow path at a location upstream of the inlet guide vane after being provided onto the stator of the electric machine.

[0090] A gas turbine engine defining a radial, an axial, and an axial extension of the gas, the gas turbine engine comprising: a static structure; a shaft configured to rotate about the axial; an electric machine comprising a rotor coupled to the shaft and rotatable therewith and a stator coupled to the static structure; a fluid seal comprising: a first member comprising a first set of sealing teeth, the first member being rotatable with the rotor of the electric machine; and a second member comprising a second set of sealing teeth, the second member being coupled to the static structure or being integral therewith, wherein the first set of sealing teeth and the second set of sealing teeth are alternately spaced apart along a length of the fluid seal.

[0091] The engine according to one or more of the clauses, wherein the length of the fluid seal is defined in the radial of the engine, and wherein the first set of sealing teeth and the second set of sealing teeth extend substantially in the axial of the engine.

[0092] The engine according to one or more of the clauses, wherein the first member defines a first plurality of valleys between adjacent sealing teeth of the first set of sealing teeth, wherein the second member defines a second plurality of valleys between adjacent sealing teeth of the second set of sealing teeth, wherein the first set of sealing teeth defines a gap in the axial from the second plurality of valleys, and wherein the second set of sealing teeth defines a gap in the axial from the first plurality of valleys.

[0093] The engine according to one or more of the clauses, wherein the first member defines a plurality of valleys between adjacent sealing teeth of the first set of sealing teeth, and wherein the plurality of valleys is coated with a wear-resistant material.

[0094] The engine according to one or more of the clauses, wherein the second member also defines a plurality of valleys between adjacent sealing teeth of the second set of sealing teeth, and wherein the plurality of valleys of the second member is also coated with a wear-resistant material.

[0095] The engine according to one or more of the clauses, wherein the sealing teeth of the first set of sealing teeth, the sealing teeth of the second set of sealing teeth, or both are coated with a wear-resistant material.

[0096] The engine according to one or more of the clauses, wherein the first set of sealing teeth comprises at least one sealing tooth, and wherein the second set of sealing teeth also comprises at least one sealing tooth.

[0097] The engine according to one or more of the clauses, wherein the first set of sealing teeth comprises at least three rows of sealing teeth, and wherein the second set of sealing teeth also comprises at least three rows of sealing teeth.

[0098] The engine according to one or more of these clauses, wherein the electric machine defines a first end and a second end in an axial direction, wherein the engine includes a cooling air assembly defining a first cooling air flow path extending to the first end of the electric machine and a second cooling air flow path extending to the second end of the electric machine, and wherein the fluid seal is in airflow communication with the first cooling air flow path and the second cooling air flow path.

[0099] The engine according to one or more of these clauses, wherein the fluid seal is configured to block passage of cooling air flow between the first cooling air flow path and the second cooling air flow path.

[0100] The engine according to one or more of these clauses, wherein one of the first member or the second member is formed of a non-metallic material.

[0101] The engine according to one or more of these clauses, wherein the second member is formed of a non-metallic material.

[0102] The engine according to one or more of these clauses, wherein the engine further includes a static manifold at the second end of the rotor of the electric machine, wherein the cooling manifold is formed of a non-metallic material, the static manifold is made of a non-metallic material, or both.

[0103] This written description uses examples to disclose the application, including the best mode, and also to enable any person skilled in the art to practice the application, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the application 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 gas turbine engine, the gas turbine engine defining a radial direction, an axial direction and an axis extending along the axial direction of the gas, characterized in that: The gas turbine engine comprises: a shaft configured to rotate about the axis; an electric motor including a rotor and a stator, the rotor being coupled to the shaft and rotatable therewith, the rotor defining an end in the axial direction; and A cooling manifold is rotatable with the rotor and positioned at the end of the rotor, the cooling manifold being configured to receive a flow of cooling fluid and provide cooling fluid to the stator during operation of the gas turbine engine.

2. The engine according to claim 1, characterized in that The gas turbine engine includes a rotor assembly, and wherein the shaft is a rotor shaft for driving a ductless rotor assembly.

3. The engine according to claim 1, characterized in that The gas turbine engine includes a compressor, and wherein the cooling fluid is an exhaust gas stream from the compressor.

4. The engine according to claim 1, characterized in that The cooling manifold is coupled to the end of the rotor of the electric machine, and wherein the end of the rotor is optionally positioned at least partially radially inward of the stator.

5. The engine according to claim 1, characterized in that The cooling manifold is coupled to the end of the rotor of the electric machine, to a rotor mount that couples the rotor to the engine shaft, or both.

6. The engine according to claim 5, characterized in that The rotor mount defines one or more openings for providing the flow of cooling fluid to the cooling manifold.

7. The engine according to claim 1, characterized in that Further included is a rotor mount extending between the shaft and the rotor, and wherein the cooling manifold is coupled to the rotor mount.

8. The engine according to claim 1, characterized in that The cooling manifold defines one or more impingement openings oriented toward the stator for providing the cooling fluid as an impingement airflow onto the stator.

9. The engine according to claim 8, characterized in that The stator includes a plurality of windings, and wherein the one or more impingement openings are oriented toward at least a portion of the plurality of windings of the stator for providing the cooling fluid as the impingement airflow onto the plurality of windings of the stator.

10. The engine according to claim 1, characterized in that The manifold is a generally annular manifold.

11. The engine according to claim 1, characterized in that Further included is a liquid cooling system, wherein the liquid cooling system is in thermal communication with the electric machine to cool the electric machine.

12. The engine according to claim 1, characterized in that Further including: a bearing that supports the rotation of the shaft, and a seal at least partially defining a bearing reservoir surrounding the bearing; as well as A cooling air flow supply is provided, wherein the cooling air flow supply is in air flow communication with the cooling manifold to provide the cooling fluid flow to the cooling manifold and in air flow communication with the seal to pressurize the seal.

13. The engine according to claim 1, characterized in that The engine is a single unducted rotor engine.

14. The engine according to claim 1, characterized in that The engine is any of the following: a ducted turbofan engine, an unducted turbofan engine, a turboprop engine, a turboshaft engine, or a turbojet engine.

15. The engine according to claim 1, characterized in that The gas turbine engine defines an engine flow path, and wherein the cooling fluid is provided to the engine flow path after being provided to the stator of the electric machine.

16. The engine according to claim 15, characterized in that The gas turbine engine includes a compressor, and wherein the cooling fluid is provided to the engine flow path at a location upstream of the compressor after being provided to the stator of the electric machine.

17. The engine according to claim 15, characterized in that The gas turbine engine includes inlet guide vanes, and wherein the cooling fluid is provided to the engine flow path at a location upstream of the inlet guide vanes after being provided to the stator of the electric machine.

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