This specification is based upon and claims the benefit of priority from United Kingdom Patent Application No. 2213999.2, filed on 26 Sep. 2022, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a dynamic sealing assembly for a rotary machine. The present disclosure relates further to a method of manufacturing a dynamic sealing assembly for a rotary machine. The present disclosure also relates to a blower assembly comprising a dynamic sealing assembly.
Rotary machines (such as turbomachines) may comprise moving components. For better performance, it is desirable to provide means for sealing moving components within a rotary machine.
Blower assemblies which make use of air which is bled from a lower pressure source of a gas turbine engine (such as a bypass duct) and which subsequently compress the air prior to delivering it to the airframe of aircraft are also known, as described in EP3517436 B1, EP3517437 B1 and EP3517438 B1. It may be especially desirable to provide means for sealing moving components within a blower assembly for an aircraft. Such means for sealing moving components may be referred to as dynamic sealing means.
According to a first aspect, there is provided a dynamic sealing assembly for a rotary machine, comprising: a primary sandwich plate comprising a plurality of primary vane openings; a secondary sandwich plate comprising a plurality of secondary vane openings; and a bristle pack comprising a plurality of bristles disposed between the primary sandwich plate and the secondary sandwich plate; wherein each of the plurality of primary vane openings overlies and aligns with a respective secondary vane opening to form a vane channel for receiving a vane along a longitudinal axis of the dynamic sealing assembly; and wherein the bristle pack is configured to: provide a brush seal between each vane received within the respective vane channels and the dynamic sealing assembly; and allow relative movement between the dynamic sealing assembly and the vane received within each vane channel along the longitudinal axis.
The longitudinal axis may be an axis extending through a geometrical centre of the dynamic sealing assembly. The dynamic sealing assembly may be annular around the longitudinal axis. The dynamic sealing assembly may be configured to translate (e.g., slide) along the longitudinal axis to effect relative movement between the dynamic sealing assembly and the respective vanes. The longitudinal axis may be coincident with a rotational axis of the rotary machine. It may be that the dynamic sealing assembly is coaxial with a rotary component of the rotary machine (e.g., a rotor).
It may be that, in each of the vane channels, a window is defined within the bristle pack to receive the respective vane therethrough. It may be that each window is formed within the bristle pack using water-jet cutting, laser cutting, or spark eroding. Each window is defined within the bristle pack such that the bristle pack protrudes into the respective vane channel to define the window. It may be that a profile of each of the windows corresponds to a cross-sectional profile of the vane to be received therein.
The bristle pack is clamped between the primary sandwich plate and the secondary sandwich plate. It may be that the bristle pack is clamped by cooperation of a primary opening boss disposed around each of the primary vane openings and an opposing secondary vane opening boss disposed around the respective secondary vane opening. It may be that each of the plurality of bristles of the bristle pack is bonded to the primary sandwich plate and/or to the secondary sandwich plate at a plurality of bonding locations, each bonding location being between a respective primary opening boss and an opposing secondary vane opening boss. Each of the plurality of bristles of the bristle pack may be bonded to the primary sandwich plate and/or to the secondary sandwich plate by brazing, laser welding or diffusion bonding.
Further, it may be that each vane channel has: an inner region located relatively proximal to a geometrical centre of the dynamic sealing assembly; and an outer region located relatively distal to the geometrical centre of the dynamic sealing assembly. The dynamic sealing arrangement may be configured such that: the bristles of the bristle pack provide greater resistance to deflection in a first direction parallel to the longitudinal axis within the inner region than within the outer region; and the bristles of the bristle pack provide greater resistance to deflection in a second direction parallel to the longitudinal axis within the outer region than within the inner region, the first direction opposing the second direction.
It may be that, in each inner region, an inner guide is disposed between the primary opening boss and the window, the inner guide protruding from the primary sandwich plate to support the bristles of the bristle pack. Additionally or alternatively, it may be that in each outer region, an outer guide is disposed between the secondary opening boss and the window, the outer guide protruding from the secondary sandwich plate to support the bristles of the bristle pack.
It may be that the primary sandwich plate comprises a plurality of throat openings, with each throat opening being in fluid communication with each other throat opening via a connecting fluid pathway. Each throat opening may be located proximal to a respective vane channel. A hole may be formed in the bristle pack at a location underlying each throat opening. It may be that each hole is formed within the bristle pack using water-jet cutting, laser cutting, or spark eroding. In addition, it may be that each hole is formed in the bristle pack such that an edge of the respective hole is substantially flush with an edge of the respective throat opening.
Further, it may be that each sandwich plate is annular around the longitudinal axis; and each of the plurality of bristles of the bristle pack extends substantially parallel a local radial direction extending from the longitudinal axis.
Each of the plurality of bristles of the bristle pack may have a melting point which is greater than 300° C. It may be that each of the plurality of bristles of the bristle pack are formed of carbon fibre or a high-nickel alloy.
According to a second aspect, there is provided a blower assembly for providing air to an airframe system, the blower assembly comprising: the dynamic sealing assembly of the first aspect; and a rotor configured to be mechanically coupled to a spool of a gas turbine engine; wherein the blower assembly is operable in a compressor configuration in which the rotor is configured to be driven to rotate by the spool and to receive and compress air from the gas turbine engine, and discharge the compressed air for supply to the airframe system; and wherein the blower assembly further comprises: a diffuser vane array comprising a plurality of diffuser vanes and configured to act together with the rotor to compress air received at the rotor in the compressor configuration, wherein the dynamic sealing assembly is positioned within the blower assembly such that each diffuser vane is partially located within a respective vane channel; and an actuator arrangement configured to cause relative movement between the dynamic sealing assembly and the diffuser vane array to adjust an effective axial height of the diffuser vanes in the compressor configuration, wherein the effective axial height is with respect to a rotational axis of the rotor.
According to a third aspect, there is provided a blower assembly for providing air to an airframe system, the blower assembly comprising: the dynamic sealing assembly of the first aspect; and a rotor configured to be mechanically coupled to a spool of a gas turbine engine; wherein the blower assembly is operable in a turbine configuration in which the rotor is configured to receive air from an external air source to drive the spool to rotate; and wherein the blower assembly further comprises: a nozzle guide vane array comprising a plurality of nozzle guide vanes and configured to act together with the rotor to expand air received at the nozzle guide vane array in the turbine configuration, wherein the dynamic sealing assembly is positioned within the blower assembly such that each nozzle guide vanes is partially located within a respective vane channel; and an actuator arrangement configured to cause relative movement between the dynamic sealing assembly and the nozzle guide vane array to adjust an effective axial height of the nozzle guide vanes in the turbine configuration, wherein the effective axial height is with respect to a rotational axis of the rotor.
According to a fourth aspect there is provided a gas turbine engine for an aircraft, the gas turbine engine comprising a blower assembly in accordance with the second aspect or the third aspect. According to a fifth aspect there is provided an aircraft comprising a blower assembly in accordance with the second aspect or the third aspect, or comprising a gas turbine engine in accordance with the fourth aspect.
As noted elsewhere herein, the present disclosure may relate to a gas turbine engine. Such a gas turbine engine may comprise an engine core comprising a turbine, a combustor, a compressor, and a core shaft connecting the turbine to the compressor. Such a gas turbine engine may comprise a fan (having fan blades) located upstream of the engine core.
Arrangements of the present disclosure may be particularly, although not exclusively, beneficial for fans that are driven via a gearbox. Accordingly, the gas turbine engine may comprise a gearbox that receives an input from the core shaft and outputs drive to the fan so as to drive the fan at a lower rotational speed than the core shaft. The input to the gearbox may be directly from the core shaft, or indirectly from the core shaft, for example via a spur shaft and/or gear. The core shaft may rigidly connect the turbine and the compressor, such that the turbine and compressor rotate at the same speed (with the fan rotating at a lower speed).
The gas turbine engine as described and/or claimed herein may have any suitable general architecture. For example, the gas turbine engine may have any desired number of shafts (or spools) that connect turbines and compressors, for example one, two or three shafts. Purely by way of example, the turbine connected to the core shaft may be a first turbine, the compressor connected to the core shaft may be a first compressor, and the core shaft may be a first core shaft. The engine core may further comprise a second turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor. The second turbine, second compressor, and second core shaft may be arranged to rotate at a higher rotational speed than the first core shaft.
In such an arrangement, the second compressor may be positioned axially downstream of the first compressor. The second compressor may be arranged to receive (for example directly receive, for example via a generally annular duct) flow from the first compressor.
The gearbox may be arranged to be driven by the core shaft that is configured to rotate (for example in use) at the lowest rotational speed (for example the first core shaft in the example above). For example, the gearbox may be arranged to be driven only by the core shaft that is configured to rotate (for example in use) at the lowest rotational speed (for example only be the first core shaft, and not the second core shaft, in the example above). Alternatively, the gearbox may be arranged to be driven by any one or more shafts, for example the first and/or second shafts in the example above.
The gearbox may be a reduction gearbox (in that the output to the fan is a lower rotational rate than the input from the core shaft). Any type of gearbox may be used. For example, the gearbox may be a “planetary” or “star” gearbox, as described in more detail elsewhere herein.
In any gas turbine engine as described and/or claimed herein, a combustor may be provided axially downstream of the fan and compressor(s). For example, the combustor may be directly downstream of (for example at the exit of) the second compressor, where a second compressor is provided. By way of further example, the flow at the exit to the combustor may be provided to the inlet of the second turbine, where a second turbine is provided. The combustor may be provided upstream of the turbine(s).
The or each compressor (for example the first compressor and second compressor as described above) may comprise any number of stages, for example multiple stages. Each stage may comprise a row of rotor blades and a row of stator vanes, which may be variable stator vanes (in that their angle of incidence may be variable). The row of rotor blades and the row of stator vanes may be axially offset from each other.
The or each turbine (for example the first turbine and second turbine as described above) may comprise any number of stages, for example multiple stages. Each stage may comprise a row of rotor blades and a row of stator vanes. The row of rotor blades and the row of stator vanes may be axially offset from each other.
According to an aspect, there is provided an aircraft comprising a cabin blower assembly or a gas turbine engine as described and/or claimed herein.
The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the above aspects may be applied mutatis mutandis to any other aspect. Furthermore except where mutually exclusive any feature described herein may be applied to any aspect and/or combined with any other feature described herein.
Examples will now be described with reference to the accompanying drawings, which are purely schematic and not to scale, and in which:
In use, the core airflow A is accelerated and compressed by the low pressure compressor 14 and directed into the high pressure compressor 15 where further compression takes place. The compressed air exhausted from the high pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture is combusted. The resultant hot combustion products then expand through, and thereby drive, the high pressure turbine 17 and low pressure turbine 19 before being exhausted through the nozzle 20 to provide some propulsive thrust. The high pressure turbine 17 drives the high pressure compressor 15 by a suitable interconnecting shaft 27. The fan 23 generally provides the majority of the propulsive thrust. The epicyclic gearbox 30 is a reduction gearbox.
An exemplary arrangement for a geared fan gas turbine engine 10 is shown in
Note that the terms “low pressure turbine” and “low pressure compressor” as used herein may be taken to mean the lowest pressure turbine stages and lowest pressure compressor stages (i.e., not including the fan 23) respectively and/or the turbine and compressor stages that are connected together by the interconnecting shaft 26 (or spool) with the lowest rotational speed in the engine (i.e., not including the gearbox output shaft that drives the fan 23). In some literature, the “low pressure turbine” and “low pressure compressor” referred to herein may alternatively be known as the “intermediate pressure turbine” and “intermediate pressure compressor”. Where such alternative nomenclature is used, the fan 23 may be referred to as a first, or lowest pressure, compression stage.
The epicyclic gearbox 30 is shown by way of example in greater detail in
The epicyclic gearbox 30 illustrated by way of example in
It will be appreciated that the arrangement shown in
Accordingly, the present disclosure extends to a gas turbine engine having any arrangement of gearbox styles (for example star or planetary), support structures, input and output shaft arrangement, and bearing locations.
Optionally, the gearbox may drive additional and/or alternative components (e.g., the intermediate pressure compressor and/or a booster compressor).
Other gas turbine engines to which the present disclosure may be applied may have alternative configurations. For example, such engines may have an alternative number of compressors and/or turbines and/or an alternative number of interconnecting shafts. By way of further example, the gas turbine engine shown in
The geometry of the gas turbine engine 10, and components thereof, is defined by a conventional axis system, comprising an axial direction (which is aligned with the rotational axis 9), a radial direction (in the bottom-to-top direction in
A diagram of an example blower assembly 400 for providing air to an airframe system is shown schematically in
The rotor 410 is configured to be driven to rotate by the spool 440 in the compressor configuration, whereby the blower assembly 410 compresses air it receives from the gas turbine engine. The compressed air is discharged to an airframe discharge nozzle 426 for supply to an airframe system 450 for an airframe pressurisation purpose. The airframe pressurisation purpose may be, for example, wing anti-icing, fuel tank inerting, cargo bay smoke eradication and/or aircraft cabin pressurisation. In the example of
The blower assembly 400 is configured to function as a compressor in the compressor configuration, such that air supplied to the airframe system 450 is at a higher pressure than air drawn from the air pathway 460 of the gas turbine engine. As a result, the blower assembly 400 is not required to draw air from a relatively high-pressure region of the gas turbine engine in order to supply pressurised air to the airframe system 450. Instead, the blower assembly 400 may draw air via the engine bleed nozzle 422 from a relatively low-pressure region of the gas turbine engine, such as from a bypass duct 22 of the gas turbine engine as shown in
The rotor 410 is driven to rotate in the compressor configuration by the variable transmission 430, which itself receives drive input from the spool 440, for example through an accessory gearbox of the gas turbine engine. The speed of rotation of the spool 440 depends on the operating point of the gas turbine engine, which dictates a speed of the spool 440. The variable transmission 430 allows a rotational speed of the rotor 410 in the compressor configuration to be decoupled from a rotational speed of the spool 440, so that a compression performance of the blower assembly 400 in the compressor configuration is not solely governed by the operating point of the gas turbine engine (e.g., it can be controlled to operate at a target speed independent of the rotational speed of the spool, and/or at a variable speed ratio relative to the rotational speed of the spool). Inclusion of a variable transmission 430 within the blower assembly 400 therefore provides more versatile and adaptable means for supplying pressurised air to an airframe system. Various suitable variable transmission types will be apparent to those of ordinary skill in the art. For example, the variable transmission 430 may comprise an electric variator, as described in EP 3517436 B1.
The blower assembly 400 is also configured to be able to receive (e.g., configured to selectively receive) compressed air from an external air source 470 to drive the spool 440 to rotate, for example for starting the gas turbine engine in the turbine configuration. In the example of
The external air source 470 may be derived from, for example, an auxiliary power unit (APU) of the aircraft or ground starting equipment (GSE). In the example of
The blower assembly 400 is configured to function as a turbine in the turbine configuration, such that the spool 440 may be driven to rotate by the rotor 410. Generally, the blower assembly 400 may be configured to drive rotation of the spool 440 to a rotational speed which is sufficient to enable the gas turbine engine to successfully execute an ignition process. Consequently, the blower assembly 400 dispenses with a need to provide a dedicated air turbine starting system or an electric starting system to the gas turbine engine, each of which are associated with additional weight and system complexity. Additionally or alternatively, the blower assembly 400 may be able to drive the spool 440 to rotate at a lower speed, for example to prevent the formation of a bowed engine rotor condition following engine shutdown or to reduce a bowed engine rotor condition prior to engine start. To this end, the start control and isolation valve 455 may be configured to control the mass flow and pressure of the air flow to a somewhat lower level than that required for engine starting.
The use of a two-configuration blower assembly 400 allows for an assembly in which the rotor 410 rotates in the same rotation direction (i.e., clockwise or anti-clockwise) in both the compressor configuration and the turbine configuration. In this way, in the turbine configuration of the blower assembly 400 the rotor 410 will drive the spool 440 to rotate in a direction that the spool 440 rotates when it drives the rotor 410 in the compressor configuration. This allows for the omission of a separate reversing mechanism to permit the spool 440 to be driven to rotate in its starting direction, which will be the same as the direction it rotates during when driving the rotor 410 in the compressor configuration. A separate reversing mechanism would result in additional mechanical efficiency losses in, and increased weight of and/or a reduced reliability of, the blower assembly 400.
Various examples of a blower assembly in accordance with the blower assembly 400 described above with respect to
In the example of
In the compressor configuration, as shown in
A geometry of each of the plurality of diffuser vanes 515 of the array may be selected so as to optimise an aerodynamic performance of the diffuser vane array 510 without compromising an aerodynamic performance of the nozzle guide vane array 520. Likewise, a geometry of each of the plurality of nozzle guide vanes 525 may be selected so as to optimise an aerodynamic performance of the nozzle guide vane array 520 without compromising an aerodynamic performance (i.e., a turbine function) of the nozzle guide vane array 510. Accordingly, an overall performance of the blower assembly 400 in both the compressor configuration and the turbine configuration may be improved by providing dedicated flow modifiers for the respective modes of operation, rather than, for example, attempting to provide a single configuration through which the flow merely passes in different directions.
The geometries of each of the plurality of diffuser vanes 515 and of each of the plurality of nozzle guide vanes 525 is predetermined and fixed in use. It may be that angles of attack of each of the plurality of diffuser vanes 515 and of each of the plurality of nozzle guide vanes is predetermined and fixed in use. By providing a fixed configuration of the respective aerodynamic components, dynamic sealing losses associated with variable geometry and/or rotatable vanes may be eliminated or reduced, and the overall performance of the blower assembly 400 may be improved in the compressor configuration and/or the turbine configuration relative to alternative blower assemblies having such features.
The example blower assembly 400 further comprises an actuator arrangement 530 configured to cause relative movement between the rotor 410 and the diffuser vane array 510 so that the diffuser vane array 510 is disposed around the rotor 410 for operating in the compressor configuration. Similarly, the actuator arrangement 530 is also configured to cause relative movement between the rotor 410 and the nozzle guide vane array 520 so that the nozzle guide vane array 520 is disposed around the rotor 410 for operating in the turbine configuration.
The actuator arrangement 530 is further configured to adjust an effective axial height of the diffuser vanes 515, the effective axial height of the diffuser vanes 515 being defined with respect to a rotational axis of the rotor 410. Accordingly, in the compressor configuration, a compression performance of the blower assembly 400 may be adjusted to meet a compression demand associated with, for example, an airframe system.
To this end, an example actuator arrangement is described below with reference to
The diffuser height actuator 634 of this example is configured to cause relative movement between the diffuser vane array 510 and a dynamic sealing assembly 700. A position of the dynamic sealing assembly 700 (e.g., an axial position) governs an effective axial height of the diffuser vanes 515 of the diffuser vane array 510. Specifically, the position of the dynamic sealing assembly 700 with respect to the diffuser vane array 510 governs a size of an open area of an inlet interface 540 between the rotor 410 and the diffuser vane array 510, and also governs the open area of the outlet at a radially outer side of the diffuser vane array 510. That is, the position of the dynamic sealing assembly 700 with respect to the diffuser vane array 510 governs a size of a cross sectional-area of the diffuser vane array 510 between the inlet interface 540 and the outlet interface 550 (best shown in
In
By comparison of
This disclosure envisages that, in addition to or instead of governing of the effective axial height of the diffuser vanes 515, an effective axial height of the nozzle guide vanes 525 (defined with respect to the rotational axis of the rotor 410) may be similarly controlled using a nozzle guide height actuator configured to cause relative movement between the nozzle guide vane array 520 and a dynamic sealing assembly 700 as described herein, and thereby adjust a turbine performance of the blower assembly 400 in the turbine configuration.
An example dynamic sealing assembly 700 is now described with reference to
The dynamic sealing assembly 700 comprises opposing sandwich plates, which are interchangeably referred to herein as a primary/upper plate and a secondary/lower plate. Features associated with each sandwich plate may also be referred to using the terms primary/upper and secondary/lower. The expressions upper and lower are used with reference to a longitudinal axis 703 along which the dynamic sealing assembly 700 is configured to be translated (e.g., moved), and it is to be appreciated that the plates are not to be interpreted as being at relatively higher or lower positions (e.g., with respect to a gravitational frame of reference). When incorporated within the blower assembly 400, the longitudinal axis 703 of the dynamic sealing assembly 700 is coincident with to the rotational axis 702 of the blower assembly 400 such that the dynamic sealing assembly 700 is coaxial with the rotor 410 of the blower assembly 400. The longitudinal axis 703 extends through a geometrical centre of the dynamic sealing assembly 700. If the dynamic sealing assembly 700 is annular, the dynamic sealing assembly 700 is therefore annular around the longitudinal axis 703.
The dynamic sealing assembly 700 comprises a primary (e.g., upper) sandwich plate 710 comprising a plurality of primary (e.g., upper) vane openings 712. In the example of
As best shown by the cross-sectional view of
The lower sandwich plate 720 comprises a plurality of secondary (e.g., lower) vane openings 722. Each of the plurality of lower vane openings 722 corresponds to a respective upper vane opening 712. Therefore, the number of lower vane openings 722 is equal to the number of upper vane openings 712. Further, the plurality of upper vane openings 712 overlie the plurality of lower vane openings 722 with respect to the longitudinal axis 703, such that each upper vane opening overlies and is aligned with a corresponding lower vane opening to form a respective vane channel. As seen in the cross-sectional view of
A plurality of windows are defined within (e.g., cut into) the bristle pack 730, with each window being defined within a respective vane channel so as to receive an aerodynamic body (e.g., a vane) therethrough along the longitudinal axis 703 of the dynamic sealing assembly 700. In the front view of
When a dynamic sealing assembly 700 as described is incorporated within a blower assembly as described above with respect to
The bristle pack 730 is generally configured to provide a brush seal between each vane received within the respective vane channels and the dynamic seal assembly (e.g., between each vane received within the respective vane channels and at least one of the sandwich plates 710, 720). The brush seal is formed by virtue of the bristles of the bristle pack 730 being proximal to, and preferably engaging (e.g., abutting contact), an outer surface of the vane 515A-515E. However, the deformable nature of the bristles of the bristle pack 730 allows limited-friction (e.g., low friction) relative movement between the dynamic sealing assembly 700 and the vanes 515A-515E received in each vane channel (through the window defined therein) along the longitudinal axis 703 of the dynamic sealing arrangement 700 vanes.
Compared to a previously considered dynamic sealing assembly, utilisation of the bristle pack 730 to provide a brush seal between the vanes 515A-515E and the dynamic sealing assembly 700 enables use of the dynamic sealing assembly 700 within a rotary machine (e.g., a turbomachine) having a higher expected maximum operational temperature. For example, in the context of the above-described blower assembly 400, the expected maximum operational temperature may be relatively high.
To aid the following description of the windows in the vane channels, an area immediately around the first upper vane opening 712A is shown in the detail front view of
Each window 735A, 735C, 735D may be formed within the bristle pack 730 using any suitable method of manufacture. Advantageously, each window 735A, 735C, 735D may be formed within the bristle pack 730 using water-jet cutting, laser cutting, or spark eroding. These techniques provide fast, effective and precise manufacturing of the dynamic sealing assembly 700. In particular, use of these methods may improve a sealing performance of the bristle pack 730 with respect to a vane received therethrough, as well as lower friction between the bristles of the bristle pack 730 and the vane during relative movement between the dynamic sealing assembly 700 and the vane in a direction parallel to the longitudinal axis of the vane in use.
Bristles of differing diameters may be used in varying quantities in the bristle pack 730 to reduce a void fraction of the bristle pack 730, the void fraction being defined as a fraction of the volume of the bristle pack 730 which is not occupied by bristle material. A reduced void fraction of the bristle pack 730 is associated with improved sealing performance of the bristle pack 730 with respect to the vane received through each window.
A respective upper vane opening boss 714A-714E is disposed around each upper vane opening 712A-712E on a side of the upper sandwich plate 710 proximal to the bristle pack 730. Although
In the example dynamic sealing assembly 700 of
It may be that the expected maximum operational temperature of the dynamic sealing assembly 700 when incorporated within a rotary machine (e.g., the blower assembly 400) is equal to or greater than 300° C. Each of the plurality of bristles of the bristle pack 730 has a melting point which is greater than 300° C. Preferably, each of the plurality of bristles of the bristle pack 730 may have a melting point greater than 350° C. or greater than 400° C. To this end, each of the plurality of bristles of the bristle pack 730 may comprise a material having a melting point greater than 300° C., greater than 350° C., or greater than 400° C. Use of such a material for the bristles of the bristle pack ensures good general performance of the dynamic sealing assembly 700 throughout the expected operational temperature range of the dynamic sealing assembly 700 when incorporated within a blower assembly (as described herein) or a similar rotary machine. Preferably, each of the plurality of bristles may be formed of carbon fibre or a high-nickel alloy (e.g., an alloy containing no less than 25% Ni by weight), which may also provide optimal mechanical performance of the bristle pack in use and thereby increase a sealing quality between the or each sandwich plate 710, 720 and a vane received within the respective vane channel.
In addition, each of the plurality of bristles of the bristle pack 730 may be bonded to the upper sandwich plate 710 or to the lower sandwich plate 720. If so, the bristles are bonded to the sandwich plates at a plurality of bonding locations. Each bonding location may be between a pair of opposing vane opening bosses or, optionally, between a pair of opposing circumferential bosses. As best seen on
Referring now to
When the vane 515A is received through the window 435A in the vane channel 715A, the bristles of the bristle pack 730 are configured to provide differing degrees of resistance to deflection in the first reference direction 702′ and the second reference direction 702″ in the inner region 715A′ and the outer region 715A″. Specifically, the bristles of the bristle pack 730 are configured to provide greater resistance to deflection in the first direction 702′ within the inner region 715A′ than within the outer region 715A″. On the other hand, the bristles of the bristle pack 730 are configured to provide greater resistance to deflection in the second direction 702″ within the outer region 715A″ than within the inner region 715A′.
To this end, in each inner region 715A′, an inner guide 719A is disposed between the primary opening boss 714A and the window 735A. The inner guide 719A protrudes from the primary sandwich plate 710 to meet and support the bristles of the bristle pack 730 at a location proximal to the window 735A and the vane 515A. The inner guide 719A allows the bristles of the bristle pack 730 to slide (e.g., translate) in the cant deflection plane while resisting movement (e.g., translation) of the bristles of the bristle pack 730 along the first direction 702′ in a longitudinal plane. The longitudinal plane as defined herein is a plane in which the rotational axis 702 lies and which locally intersects the bristle pack. Therefore, the bristles of the bristle pack 730 may provide greater resistance to deflection in the first direction 702′ compared to deflection in the second direction 702″ within the inner region 715A′.
Similarly, in each outer region 715A″, an outer guide 729A is disposed between the secondary opening boss 724A and the window 735A. The outer guide 729A protrudes from the secondary sandwich plate 720 to meet and support the bristles of the bristle pack 730 at a location proximal to the window 735A and the vane 515A. The outer guide 729A allows the bristles of the bristle pack 730 to slide (e.g., translate) in the cant deflection plane while resisting movement (e.g., translation) of the bristles of the bristle pack 730 along the second direction 702″ in the longitudinal plane within the outer region 715A″. Therefore, the bristles of the bristle pack 730 may provide greater resistance to deflection in the second direction 702″ compared to deflection in the first direction 702′ within the outer region 715A″. Without wishing to be bound by theory, those skilled in the art will understand that according to classical beam theory, this arrangement ensures that a force required to cause a specified flexural deflection of the bristles of the bristle pack 730 in the first direction is higher within the inner region 715A′ than within the outer region 715A″. On the other hand, a force required to cause a specified flexural deflection of the bristles in the second direction is higher within the outer region 715A″ than within the inner region 715A′.
The inner guide 719A is separated from the primary opening boss 714A by an inner intervening space 719A*. The inner guide 719A meets the primary opening boss 714A at a location proximal to the outer region 715A″ (shown as being proximal to the illustrative dividing line 715* in
Some benefits of these features are now explained in the context of the blower assembly 400 with reference to
As discussed above, the diffuser vanes 515 of the diffuser vane array 510 are configured to act together with the rotor 410 to compress air received at the rotor 410 by converting kinetic energy of air received from the rotor 410 into static pressure energy. Therefore, when the blower assembly 400 is operating as a compressor, the static pressure of air within the open region 514 adjacent to the inner region 715A′ (proximal to the geometrical centre of the rotor 410) is significantly lower than the static pressure of air within the open region 514 adjacent to the outer region 715A″ (distal to the geometrical centre of the rotor 410). In particular, it may be that the static pressure of air within the open region 514 adjacent to the inner region 715A′ is lower than the static pressure of ambient air within the closed region 512 adjacent to the inner region 715A′ and the static pressure of air within the open region 514 adjacent to the outer region 715A″ is greater than the static pressure of ambient air within the closed region 512 adjacent to the outer region 715A″.
As a result of these differences in static pressure, air leakage may occur between the open region 514 of the diffuser vane array 510 and the closed region 512 of the diffuser vane array 510 across the first vane channel 715A of the dynamic sealing assembly 700. The magnitude and direction of air leakage across the first vane channel 715A is indicated by the plurality of arrows 611′-614′ on
By configuring the bristles of the bristle pack 730 to provide greater resistance to deflection in the first direction 702′ within the inner region 715A′, the static driving pressure difference within the inner region 715A′ may be better resisted by the bristles of the bristle pack 730. Likewise, by configuring the bristles of the bristle pack 730 to provide greater resistance to deflection in the second direction 702″ within the outer region 715A″, the static driving pressure difference within the inner region 715A′ may be better resisted by the bristles of the bristle pack 730.
In use, the static pressure differential between the open 514 and closed 512 regions causes air having a relatively high static pressure to flow into the inner intervening space 719A* and into the outer intervening space 729A* from the region having the relatively higher static pressure (compare
Accordingly, the features described above with respect to
When incorporated within a rotary machine (such as the blower assembly 400 described above with reference to
The provision of the plurality of throat openings 713A-713D together with the connecting fluid pathway allows a degree of pressure equalisation between the locations of the throat openings 713A-713D. The locations of each of the throat openings 713A-713D correspond to the locations at which the largest pressure differences are likely to develop, as described above. Therefore, the throat openings 713A-713D and the connecting fluid pathway provide pressure equalisation functionality to the dynamic sealing assembly 700, which is associated with an increased efficiency and performance of a rotary machine in which the dynamic sealing assembly 700 is positioned. In some examples, the connecting fluid pathway may be a fixed volume which is wholly disposed within the upper sandwich plate 710 such that the connecting fluid pathway is internal to the upper sandwich plate 710. In other examples, the connecting fluid pathway may be partially disposed within the upper sandwich plate 710 and partially disposed outside of the upper sandwich plate 710.
To facilitate pressure equalisation functionality provided to the dynamic sealing assembly 700 by the cooperation of the throat openings 713A-713D and the connecting fluid pathway, a hole may be formed in the bristle pack 730 at a location underlying each throat opening 713A-713D. Preferably, each hole may be formed within the bristle pack 730 so as to be substantially flush with an edge of the corresponding throat opening 713A-713D to provide improved pressure equalisation function to the dynamic sealing assembly 700. Each hole may be formed within the bristle pack 730 using any suitable method of manufacture. Advantageously, each hole may be formed within the bristle pack 730 using water-jet cutting, laser cutting, or spark eroding to enable fast, effective and precise manufacturing of the dynamic sealing assembly 700.
Although the dynamic sealing assembly 700 has been described in the context of a blower assembly 400 which is operable in both a compressor configuration and a turbine configuration, this need not necessarily be the case. For instance, the dynamic sealing assembly 700 is suitable for use in a blower assembly which is only operable in the compressor configuration or a turbine configuration, and in which the actuator arrangement is not configured to cause relative movement between the rotor and the diffuser vane array for operating in the compressor configuration or to cause relative movement between the rotor and the nozzle guide vane array for operating in the turbine configuration. In other words, the dynamic sealing assembly 700 is suitable for use in the blower assembly which is not operable in a turbine configuration and which does not comprise a nozzle guide vane array. In such a blower assembly, the actuator arrangement may only be configured to cause relative movement between the dynamic sealing assembly and a diffuser vane array to adjust an effective axial height of a plurality of diffuser vanes of the diffuser vane array in a compressor configuration. Similarly, the dynamic sealing assembly 700 is suitable for use in a blower assembly which is not operable in a compressor configuration and which does not comprise a diffuser vane array. If so, the actuator assembly may only be configured to cause relative movement between the dynamic sealing assembly and a nozzle guide vane array to adjust an effective axial height of a plurality of nozzle guide vanes of the nozzle guide vane array in a turbine configuration.
More generally, it will be appreciated that the dynamic sealing assembly 700 may be used in the context of other types of rotary machines (e.g., centrifugal compressors, centrifugal turbines, axial compressors, axial turbines and the like). In particular, the dynamic sealing assembly 700 may be in a non-annular (e.g., non-round) form. In addition, although it has been described that the bristle pack 730 is clamped between the upper sandwich plate 710 and the lower sandwich plate 720 such that the sandwich plates have substantially parallel and substantially flat outer surfaces, this need not be the case. For example, the outer surfaces of the sandwich plates may not be parallel and/or the outer surfaces of the sandwich plates may have different forms. To give an example, both of the sandwich plates 710, 720 may instead have a conical outer surface. To give a further example, the upper sandwich plate 710 may have a flat outer surface, whereas the lower sandwich plate 720 have a conical outer surface. The dynamic sealing assembly 700 is broadly suitable for use in a variety of technical areas, including aerospace applications, marine applications, automotive applications and the like.
It will be understood that the disclosure is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein. The scope of protection is defined in the appended claims.
Number | Date | Country | Kind |
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2213999 | Sep 2022 | GB | national |
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Great Britain search report dated Mar. 3, 2023, issued in GB Patent Application No. 2213999.2. |
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Number | Date | Country | |
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20240102399 A1 | Mar 2024 | US |