EP3611387B1 - Blade wheel of a turbomachine - Google Patents

Description

The invention relates to an impeller of a turbomachine according to the preamble of claim 1.

It is known that the blades of the compressors of an engine experience non-synchronous vibrations. One phenomenon that occurs is known as rotating stall, in which the flow break-off pattern in the rotor's reference system rotates. It behaves in such a way that the tear-off process is locally limited to individual blade areas. It can be one or more rotating tear-off patterns. Often the rotating stall patterns are limited to a limited radial blade area. The rotating separation disadvantageously excites the individual blades to oscillate or vibrate, which reduces the life of the blades. Blade failure due to resonance is also possible if the periodic excitations are in the range of the natural vibrations of the blades. If a compressor is operated over a long period of time with rotating detachment, heat damage to the blades can also occur.

From the US 2014/0286758 A1 a generic blade wheel is known in which the blades of a blade row are divided into two or more segments which comprise a different number of blades. In order to achieve, despite the different number of blades in the segments, that the narrowest distance between the blades is always the same, the blades are aligned differently in the respective segments.

the DE 10 2016 212 767 A1 describes an adjustable turbomachine vane grid with at least one first vane, which has a first distance in the peripheral direction from an adjacent vane in the circumferential direction, and with at least one second vane, which has a second distance in the peripheral direction from an adjacent vane in the peripheral direction, which is smaller than the first distance is. Furthermore, an adjustment device is provided for the common and / or reversible adjustment of the first and second blades from a first position to a second position.

The invention is based on the object of providing a bucket wheel of a turbomachine and a bucket wheel arrangement in which the vibrations generated by a rotating separation are reduced.

This object is achieved by a paddle wheel with the features of claim 1 and a paddle wheel arrangement with the features of claim 6. Refinements of the invention are given in the dependent claims.

The invention then contemplates a blade wheel of an axial turbomachine which has a plurality of blades. The blades are suitable and intended to extend radially in a flow path of the axial flow machine and form a row of blades. The blades form a blade inlet angle and a blade outlet angle.

According to a first aspect of the invention it is provided that the majority of the blades of the blade wheel form N blocks of blades with N> 2, the blades within a block each having the same blade inlet angle and the same blade outlet angle, and the blades of at least two adjacent blocks have a different blade inlet angle and / or a different blade outlet angle. The number N is a natural number.

According to this, the solution according to the invention is based on the idea of avoiding or reducing the occurrence of a rotating detachment by introducing a changing aerodynamic load that acts on the blades. The paddle wheel under consideration can be a rotor with rotor blades or a stator with stator blades. As will be explained below, the invention also considers combinations of paddle wheels in individual aspects.

The phenomenon of a rotating separation is based on the fact that a flow separation occurs in individual vane channels. The flow material accumulates in front of the detached blade channel and is pushed to the side (in the circumferential direction and against the rotation of the rotor). As a result, the flow against the neighboring blade is at a steeper flow angle and a flow stall occurs here as well. Due to the blocks of blades provided according to the invention, which have different blade inlet angles and / or blade outlet angles, the blades in the individual blocks flow onto the blades at different angles or the flow leaves the blades of the individual blocks at different angles. It was found that this prevents the formation of rotating cells or weakens such cells.

The paddle wheel can have an even or an odd number of blades. With an even number of blades, it can be provided that two adjacent blocks of blades each have a different blade inlet angle and / or a different blade outlet angle, the change in angle thus being alternating. In the case of an odd number of blades it can be provided that there is no change in the blade inlet angle and the blade outlet angle between two of the adjacent blocks in order to take account of the odd number of blocks, but between the other of the adjacent blocks. It is further pointed out that the blocks of the impeller in one embodiment form a total of two different blade inlet angles and / or blade outlet angles, that is, the alternating angle change relates to the same angle in each case.

One embodiment of the invention provides that the blades of at least two adjoining blocks have a different blade inlet angle and a different blade outlet angle in that the blades of the blocks form a different stagger angle with an identical shape of the blades. The blades of adjacent blocks thus have a different stagger angle. Viewed individually, the blades all have the same shape. They are simply arranged in different blocks at a different stagger angle.

An alternative embodiment of the invention provides that the blades of at least two adjacent blocks have a different blade inlet angle or a different blade outlet angle in that the blades of the blocks have a different shape. In this variant of the invention, the different angles are thus not achieved via the staggering angle, but rather via the shape of the blades. If the impeller is a rotor, in particular the blade entry angle is designed differently for adjacent blocks. If the impeller is a stator, in particular the blade exit angle is designed differently for adjacent blocks.

According to one embodiment, it is provided that the individual blocks have the same extension angle in the circumferential direction. The individual blocks thus have the same size or the same number of blades, although provision is made that, in the event of an odd number of blades, a block has one more blade than the other blocks.

Alternatively, it can be provided that at least two of the blocks have a different extension angle in the circumferential direction, the blocks with different extension angles having a different number of blades. One embodiment for this provides that all of the blocks have a different extension angle in the circumferential direction and accordingly a different number of blades.

Another embodiment provides that the blades of one block are open with respect to a nominal blade position and the blades of an adjacent block are closed with respect to the nominal blade position. A nominal blade position is one that the blades of the impeller would assume without the invention. The nominal blade position represents, so to speak, an imaginary starting position of the blade position, from which the blades are further closed or further opened depending on the block under consideration.

It can be provided that the blades of different blocks, starting from the nominal blade position, are opened or closed by the same amount of change in one direction and in the other direction. However, this is not necessarily the case. The amount of change in one direction (for example "opening") does not necessarily have to correspond to the amount of change in the other direction. It can also be provided in further design variants that the blade inlet angle and / or the blade outlet angle between adjacent blocks does not change discretely but rather continuously, for example in accordance with the shape of a sinusoidal curve.

The invention also provides that the following applies to the angular position of the blades of the individual blocks: $${\phi }_l={\phi }_0+{\displaystyle {\sum }_{k=1}^N{a}_k\cos }\left(\frac{2\mathit{k\pi }}{N}l\right)+b_k\sin \left(\frac{2\mathit{k\pi }}{N}l\right)$$

• ϕ der Schaufeleintrittswinkel, der Schaufelaustrittswinkel oder der Staffelungswinkel der Schaufeln eines betrachteten Blocks ist;
• a_k, b_k frei wählbare Koeffizienten sind, die im Intervall [-10°, 10°] liegen;
• der Index "l" die Nummer des betrachteten Blocks angibt;
• N die Gesamtzahl der Blöcke angibt, wobei N>2 ist;
• der Index "k" den Laufindex der Koeffizienten angibt, mit k = 1, ..., N;
• ϕ₀ der mittlere Winkel ist, der eingestellt ist.

It applies that

• ϕ is the blade inlet angle, the blade outlet angle or the stagger angle of the blades of a block under consideration;
• a _k , b _{k are} freely selectable coefficients which lie in the interval [-10 °, 10 °];
• the index " l " indicates the number of the block under consideration;
• N is the total number of blocks, where N>2;
• the index "k" indicates the index of the coefficients, with k = 1, ..., N;
• ϕ _{0 is} the mean angle that is set.

It applies to the coefficients a _k , b _k that for at least two values of the index “k” it is true that both coefficients a _k , b _{k are not} equal to zero. If N is 3, for example, at least two of the coefficients a ₁ , a ₂ , a ₃ , b ₁ b ₂ b _{3 are} not equal to zero. By varying the blade inlet angle, the blade outlet angle or the stagger angle of the blades of different blocks according to the formula mentioned, patterns can be generated which do not have a common period over the circumference. In this way, the build-up of rotating cells can be effectively prevented or weakened.

According to a further aspect of the invention, the invention relates to an impeller arrangement for a compressor of a turbomachine, which has: a first impeller, which is designed as an impeller, a second impeller, which is arranged upstream of the first impeller and is designed as a stator, and a third impeller, which is arranged downstream of the first impeller and designed as a stator. It is provided that at least one of the blade wheels is designed as a blade wheel according to claim 1 and thus forms N blocks of blades with N> 2, the blades of a block each having the same blade inlet angle and the same blade outlet angle, and the blades of at least two adjacent ones Blocks have a different blade inlet angle and / or a different blade outlet angle.

One embodiment variant provides that the second paddle wheel and the third paddle wheel are designed as a paddle wheel according to claim 1, both paddle wheels forming the same number of N blocks of blades with N> 2. According to this embodiment variant, the two stators of the stator-rotor-stator sequence under consideration are designed in accordance with the present invention.

This means that the rotor arranged between the two stators passes flow blocks with different angles of incidence during one revolution. As a result, changing aerodynamic and aeromechanical loads are exerted on the rotor. This prevents the development of rotating peel cells, as their development takes a certain amount of time over more than one revolution. An aerodynamic instability is created, which changes the vibration response of the rotor and suppresses vibrations to a greater extent.

The size of the blocks and the variation of the blade inlet angle and / or blade outlet angle must be set in such a way that the redistribution of flowing mass is sufficiently large to avoid or significantly suppress the development of a radially limited tear-off pattern.

A further embodiment of the invention provides for the first impeller, that is to say the rotor of the stator-rotor-stator sequence under consideration, to be designed as an impeller according to claim 1.

In this variant of the invention, the different angles of the rotor blades of different blocks stimulate the formation of cells with rotating detachment to different degrees. This asymmetry suppresses the formation of a coherent detachment pattern with rotating cells. Instead, a broadband excitation of the rotor blades takes place, which, however, is unproblematic as it leads to lower oscillation amplitudes.

The size of the blocks and the variation of the blade inlet angle and / or blade outlet angle must be adjusted in such a way that the redistribution of flowing mass is sufficiently large to avoid or significantly suppress the development of a radially limited tear-off pattern.

In further refinements of the invention, it can be provided that in the stator-rotor-stator arrangement under consideration, all of the paddle wheels are designed in accordance with the present invention, or that only one of the stators is designed in accordance with the present invention. The said angles can be varied, as explained in relation to the individual blade wheel, by varying the staggering angle or by varying the shape of the blades of the individual blocks. A variation of the stagger angle on a paddle wheel with a Variation of the shape of the blades can be combined on another blade wheel.

Another embodiment of the invention provides that the second impeller, which is designed as a stator, is designed as an inlet stator. Aircraft engine compressors are designed for a specific design speed. Particularly in the partial load range, i.e. at speeds below the design speed, there is a risk of local flow separation on the rotor blades of the compressor grille. To reduce the risk of flow separation in the partial load range, it is known to arrange a stator with possibly adjustable stator blades in front of the first rotor of the compressor. Such a stator is referred to as an inlet guide vane or inlet guide vane or as an IGV (IGV - Inlet Guide Vane). Inlet idlers increase the swirl in the flow and improve the working range of a compressor.

However, the invention is in no way restricted to the fact that the upstream row of blades is designed as an inlet guide vane. The upstream row of blades can also be a normal stator of a compressor. The invention can thus be implemented both in front stages and in stages that are embedded in a compressor.

According to a further embodiment, the second impeller has N blocks of blades, at least two of the blocks having a different blade exit angle. The third blade wheel likewise has N blocks of blades, at least two of the blocks having a different blade outlet angle. In the case of the second and third vane wheels, which are designed as stators, the vane exit angle is thus varied according to this embodiment of the invention. In the case of the first impeller, which is designed as a rotor, on the other hand, according to one embodiment of the invention, the blade inlet angle is varied.

According to a further embodiment, the first impeller has N blocks of blades, at least two of the blocks having a different blade entry angle.

However, variants are also possible in which the downstream third impeller or the row of blades formed by it only has a change in the blade inlet angle, while the upstream second impeller, in the form of a stator, has a change in the blade outlet angle having. This serves to adapt the angle of incidence to the variation in circumference caused by the impeller located upstream. The vane entry angle is increased in the area of the stator closed upstream and the vane entry angle is reduced in the area of the stator open upstream.

A further embodiment of the invention provides that a block or peripheral area of the second impeller, in which the blades of the block are more closed compared to a nominal blade position, is assigned a block or peripheral area of the third impeller in which the blades of the block are opposite a nominal blade position are more open. The flow, which has undergone a greater deflection in a block of the second, upstream impeller, is thus less deflected in the corresponding block of the third, downstream impeller, and vice versa.

• einen Triebwerkskern, der eine Turbine, einen Verdichter mit einer erfindungsgemäßen Schaufelradanordnung und eine die Turbine mit dem Verdichter verbindende, als Hohlwelle ausgebildete Turbinenwelle umfasst;
• einen Fan, der stromaufwärts des Triebwerkskerns positioniert ist, wobei der Fan mehrere Fanschaufeln umfasst; und
• ein Getriebe, das einen Eingang von der Turbinenwelle empfängt und Antrieb für den Fan zum Antreiben des Fans mit einer niedrigeren Drehzahl als die Turbinenwelle abgibt.

The present disclosure also comprises a gas turbine engine, in particular for an aircraft, with a fan wheel arrangement according to the invention. It can be provided that the gas turbine engine has:

• an engine core which comprises a turbine, a compressor with a blade wheel arrangement according to the invention and a turbine shaft which is designed as a hollow shaft and connects the turbine to the compressor;
• a fan positioned upstream of the engine core, the fan including a plurality of fan blades; and
• a gearbox that receives an input from the turbine shaft and provides drive for the fan to drive the fan at a lower speed than the turbine shaft.

• die Turbine eine erste Turbine ist, der Verdichter ein erster Verdichter ist und die Turbinenwelle eine erste Turbinenwelle ist;
• der Triebwerkskern ferner eine zweite Turbine, einen zweiten Verdichter und eine zweite Turbinenwelle, die die zweite Turbine mit dem zweiten Verdichter verbindet, umfasst; und
• die zweite Turbine, der zweite Verdichter und die zweite Turbinenwelle dahingehend angeordnet sind, sich mit einer höheren Drehzahl als die erste Turbinenwelle zu drehen.

A configuration for this can provide that

• the turbine is a first turbine, the compressor is a first compressor, and the turbine shaft is a first turbine shaft;
• the engine core further comprises a second turbine, a second compressor, and a second turbine shaft connecting the second turbine to the second compressor; and
• the second turbine, the second compressor, and the second turbine shaft are arranged to rotate at a higher speed than the first turbine shaft.

It should be noted that the present invention, insofar as it relates to an aircraft engine, is described with reference to a cylindrical coordinate system which has the coordinates x, r and ϕ. Here x indicates the axial direction, r the radial direction and ϕ the angle in the circumferential direction. The axial direction is identical to the machine axis of a gas turbine engine in which the impeller or the impeller arrangement is arranged. Starting from the x-axis, the radial direction points radially outwards. Terms such as "in front of", "behind", "front" and "rear" relate to the axial direction or the direction of flow in the engine in which the planetary gear is arranged. Terms like "outer" or "inner" refer to the radial direction.

As noted elsewhere herein, the present disclosure may relate to a gas turbine engine. Such a gas turbine engine may include an engine core that includes a turbine, a combustion chamber, a compressor, and a core shaft connecting the turbine to the compressor. Such a gas turbine engine may include a fan (with fan blades) positioned upstream of the engine core.

Arrangements of the present disclosure may be particularly, but not exclusively, advantageous for fans that are driven via a transmission. Accordingly, the gas turbine engine may include a transmission that receives an input from the core shaft and provides drive for the fan to drive the fan at a lower speed than the core shaft. The input for the transmission can take place directly from the core shaft or indirectly from the core shaft, for example via a spur shaft and / or a spur gear. The core shaft can with the turbine and rigidly connected to the compressor so that the turbine and the compressor rotate at the same speed (with the fan rotating at a lower speed).

The gas turbine engine described herein can have any suitable general architecture. For example, the gas turbine engine can have any desired number of shafts connecting turbines and compressors, such as one, two, or three shafts. By way of example only, the turbine connected to the core shaft can be a first turbine, the compressor connected to the core shaft can be a first compressor, and the core shaft can be a first core shaft. The engine core may further include a second turbine, a second compressor, and a second core shaft connecting the second turbine to the second compressor. The second turbine, the second compressor, and the second core shaft may be arranged to rotate at a higher speed than the first core shaft.

With such an arrangement, the second compressor can be positioned axially downstream of the first compressor. The second compressor may be arranged to receive flow from the first compressor (e.g., receive directly, e.g., via a generally annular channel).

The gearbox can be arranged to be driven by the core shaft configured to rotate (e.g. in use) at the lowest speed (e.g. the first core shaft in the above example). For example, the transmission can be arranged to be driven only by the core shaft which is configured to rotate (e.g. in use) at the lowest speed (e.g. only by the first core shaft and not the second core shaft in the above example) will. Alternatively, the transmission can be arranged to be driven by one or more shafts, for example the first and / or the second shaft in the above example.

In a gas turbine engine described herein, a combustion chamber may be provided axially downstream of the fan and compressor (s). For example, the combustion chamber can be located directly downstream of the second compressor (for example at its outlet) if a second compressor is provided. As a further example, the flow at the outlet of the compressor be fed to the inlet of the second turbine if a second turbine is provided. The combustion chamber can be provided upstream of the turbine (s).

The or each compressor (for example the first compressor and the second compressor as described above) can comprise any number of stages, for example a plurality of stages. Each stage can include a series of rotor blades and a series of stator blades, which can be variable stator blades (in that their angle of attack can be variable). The row of rotor blades and the row of stator blades can be axially offset from one another.

The or each turbine (for example the first turbine and the second turbine as described above) can comprise any number of stages, for example multiple stages. Each stage can include a number of rotor blades and a number of stator blades. The row of rotor blades and the row of stator blades can be axially offset from one another.

Each fan blade may be defined with a radial span extending from a root (or hub) at a radially inward gas overflow location or at a 0% span position to a tip at a 100% span position. The ratio of the radius of the fan blade at the hub to the radius of the fan blade at the tip may be less than (or on the order of): 0.4, 0.39, 0.38, 0.37, 0.36, 0, 35, 0.34, 0.33, 0.32, 0.31, 0.3, 0.29, 0.28, 0.27, 0.26 or 0.25. The ratio of the radius of the fan blade at the hub to the radius of the fan blade at the tip can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits). These ratios can generally be referred to as the hub-to-tip ratio. The radius at the hub and the radius at the tip can both be measured at the leading edge portion (or axially most forward edge) of the blade. The hub-to-tip ratio, of course, relates to the portion of the fan blade overflowing with gas; H. the portion that is radially outside of any platform.

The radius of the fan can be measured between the centerline of the engine and the tip of the fan blade at its leading edge. The diameter of the Fan (which can be simply twice the radius of the fan) can be larger than (or on the order of): 250 cm (about 100 inches), 260 cm, 270 cm (about 105 inches), 280 cm (about 110 inches) , 290 cm (about 115 inches), 300 cm (about 120 inches), 310 cm, 320 cm (about 125 inches), 330 cm (about 130 inches), 340 cm (about 135 inches), 350 cm, 360 cm ( about 140 inches), 370 cm (about 145 inches), 380 cm (about 150 inches), or 390 cm (about 155 inches). The fan diameter can be in an inclusive range bounded by two of the values in the preceding sentence (ie the values can be upper or lower limits).

The speed of the fan can vary with use. In general, the speed is lower for fans with a larger diameter. By way of non-limiting example only, the speed of the fan under constant speed conditions may be less than 2500 rpm, for example less than 2300 rpm. Merely as a further non-limiting example, the speed of the fan under constant speed conditions for an engine with a fan diameter in the range from 250 cm to 300 cm (for example 250 cm to 280 cm) in the range from 1700 rpm to 2500 rpm, for example in the range from 1800 rpm to 2300 rpm, for example in the range from 1900 rpm to 2100 rpm. Merely as a further non-limiting example, the speed of the fan under constant speed conditions for an engine with a fan diameter in the range from 320 cm to 380 cm in the range from 1200 rpm to 2000 rpm, for example in the range from 1300 rpm min to 1800 rpm, for example in the range from 1400 rpm to 1600 rpm.

When the gas turbine engine is in use, the fan (with associated fan blades) rotates about an axis of rotation. This rotation causes the tip of the fan blade to move _{at a speed U tip.} The work done by the fan blades on the flow results in an increase in the enthalpy dH of the flow. _{A fan peak} load can be defined as dH / U ^{peak 2} , where dH is the enthalpy increase (e.g. the average 1-D enthalpy increase) across the fan and U _{peak is} the (translational) speed of the fan tip, e.g. at the front edge of the tip , (which can be defined as the fan tip radius at the front edge multiplied by the angular velocity). The fan peak load at constant speed conditions can be more than (or on the order of): 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38 , 0.39, or 0.4 (where all units in this section are Jkg ^-1 K ^-1 / (ms ^-1 ) ² ). The fan peak load can be in an inclusive range bounded by two of the values in the previous sentence (ie the values can be upper or lower limits).

Gas turbine engines in accordance with the present disclosure may have any desired bypass ratio, the bypass ratio being defined as the ratio of the mass flow rate of the flow through the bypass duct to the mass flow rate of the flow through the core at constant velocity conditions. In some arrangements, the bypass ratio can be more than (on the order of): 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5 , 16, 16.5, or 17. The bypass ratio can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits). The bypass channel can be essentially ring-shaped. The bypass duct can be located radially outside the engine core. The radially outer surface of the bypass duct can be defined by an engine nacelle and / or a fan housing.

The total pressure ratio of a gas turbine engine described herein can be defined as the ratio of the back pressure upstream of the fan to the back pressure at the exit of the super high pressure compressor (before the entrance to the combustion chamber). As a non-limiting example, the total pressure ratio of a gas turbine engine described and / or claimed herein at constant speed may be greater than (or on the order of): 35, 40, 45, 50, 55, 60, 65, 70, 75 (lie). The total pressure ratio can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits).

The specific thrust of an engine can be defined as the net thrust of the engine divided by the total mass flow through the engine. Under constant speed conditions, the specific thrust of an engine described and / or claimed here can be less than (or in the order of magnitude of): 110 Nkg ^-1 s, 105 Nkg ^-1 s, 100 Nkg ^-1 s, 95 Nkg ^-1 s, 90 Nkg ^-1 s, 85 Nkg ^-1 s or 80 Nkg ^-1 s. The specific thrust can lie in an inclusive range which is limited by two of the values in the preceding sentence (ie the values can form upper or lower limits). Such Engines can be particularly efficient compared to conventional gas turbine engines.

A gas turbine engine described herein can have any maximum thrust desired. As a non-limiting example, a gas turbine described and / or claimed herein can be used to generate a maximum thrust of at least (or on the order of): 160kN, 170kN, 180kN, 190kN, 200kN, 250kN, 300kN, 350kN, 400kN , 450kN, 500kN or 550kN. The maximum thrust can be in an inclusive range bounded by two of the values in the preceding sentence (i.e. the values can be upper or lower limits). The thrust referred to above may be the maximum net thrust under standard atmospheric conditions at sea level plus 15 degrees C (ambient pressure 101.3 kPa, temperature 30 degrees C) with a static engine.

In use, the temperature of the flow at the inlet of the high pressure turbine can be particularly high. This temperature, which can be referred to as TET, can be measured at the exit to the combustion chamber, for example immediately upstream of the first turbine blade, which in turn can be referred to as a nozzle guide vane. At constant speed, the TET can be at least (or on the order of): 1400K, 1450K, 1500K, 1550K, 1600K or 1650K. The TET at constant speed can be in an inclusive range bounded by two of the values in the preceding sentence (i.e., the values can be upper or lower limits). The maximum TET when the engine is in use can, for example, be at least (or on the order of): 1700K, 1750K, 1800K, 1850K, 1900K, 1950K or 2000K. The maximum TET can be in an inclusive range bounded by two of the values in the preceding sentence (i.e. the values can be upper or lower limits). The maximum TET can occur, for example, in a condition of high thrust, for example in an MTO condition (MTO - maximum take-off thrust - maximum take-off thrust).

A fan blade and / or a blade portion of a fan blade described herein can be made from any suitable material or combination of materials. For example, at least a portion of the fan blade and / or the blade can be made at least in part from a composite, for example a metal matrix composite and / or a Organic matrix composite such as B. carbon fiber. As another example, at least a portion of the fan blade and / or the blade can be at least in part made of a metal, such as metal. A titanium-based metal or an aluminum-based material (such as an aluminum-lithium alloy) or a steel-based material. The fan blade can include at least two sections made using different materials. For example, the fan blade may have a leading edge that is made using a material that can withstand impact (such as birds, ice, or other material) better than the rest of the blade. Such a leading edge can be made using titanium or a titanium-based alloy, for example. Thus, by way of example only, the fan blade may have a carbon fiber or aluminum based body (such as an aluminum-lithium alloy) with a leading edge made of titanium.

A fan described herein may include a central portion from which the fan blades may extend, for example in a radial direction. The fan blades can be attached to the central section in any desired manner. For example, each fan blade can include a fixation device that can engage a corresponding slot in the hub (or disc). Only as an example, such a fixing device can be in the form of a dovetail which can be inserted into a corresponding slot in the hub / disc and / or brought into engagement therewith in order to fix the fan blade to the hub / disc. As another example, the fan blades can be formed integrally with a central portion. Such an arrangement can be referred to as a blisk or a bling. Any suitable method can be used to manufacture such a blisk or bling. For example, at least a portion of the fan blades can be machined from a block and / or at least a portion of the fan blades can be welded, e.g. B. linear friction welding, can be attached to the hub / disc.

The gas turbine engines described here may or may not have a VAN (Variable Area Nozzle). Such a nozzle with a variable cross-section can allow the exit cross-section of the bypass channel to be varied in use. The general Principles of the present disclosure may apply to engines with or without a VAN.

The fan of a gas turbine described herein can have any desired number of fan blades, for example 16, 18, 20, or 22 fan blades.

As used herein, constant speed conditions may mean constant speed conditions of an aircraft on which the gas turbine engine is mounted. Such constant speed conditions can conventionally be defined as the conditions during the middle part of the flight, for example the conditions to which the aircraft and / or the engine are exposed between (in terms of time and / or distance) the end of the climb and the start of the descent. will.

By way of example only, the forward speed under the constant speed condition may be at any point in the range of Mach 0.7 to 0.9, e.g. 0.75 to 0.85, e.g. 0.76 to 0.84, e.g. 0.77 to 0 .83, for example 0.78 to 0.82, for example 0.79 to 0.81, for example in the order of Mach 0.8, in the order of Mach 0.85 or in the range from 0.8 to 0, 85 lie. Any speed within these ranges can be the constant travel condition. For some aircraft, the cruise control conditions may be outside of these ranges, for example below Mach 0.7 or above Mach 0.9.

By way of example only, the constant velocity conditions may standard atmospheric conditions at an altitude that is in the range of 10,000 m to 15,000 m, for example in the range of 10,000 m to 12,000 m, for example in the range of 10,400 m to 11,600 m (about 38,000 feet), for example in Range from 10,500 m to 11,500 m, for example in the range from 10,600 m to 11,400 m, for example in the range from 10,700 m (about 35,000 feet) to 11,300 m, for example in the range from 10,800 m to 11,200 m, for example in the range from 10,900 m to 11,100 m, for example in the order of 11,000 m, correspond. The constant velocity conditions can correspond to standard atmospheric conditions at any given altitude in these areas.

By way of example only, the constant speed conditions may correspond to: a forward Mach number of 0.8; a pressure of 23,000 Pa and a temperature of -55 degrees C.

As used throughout, "constant speed" or "constant speed conditions" may mean the aerodynamic design point. Such an aerodynamic design point (or ADP) may correspond to the conditions (including, for example, Mach number, environmental conditions, and thrust requirement) for which the blower is designed to operate. This can mean, for example, the conditions under which the fan (or the gas turbine engine) has the optimum efficiency according to its design.

In use, a gas turbine engine described herein can be operated at the constant speed conditions defined elsewhere herein. Such constant speed conditions may be determined by the constant speed conditions (e.g., the conditions during the middle part of flight) of an aircraft to which at least one (e.g. 2 or 4) gas turbine engine may be attached to provide thrust.

It will be understood by those skilled in the art that a feature or parameter described in relation to any of the above aspects can be applied to any other aspect, provided that they are not mutually exclusive. Furthermore, any feature or parameter described here can be applied to any aspect and / or combined with any other feature or parameter described here, insofar as they are compatible not mutually exclusive. The scope of the invention is defined solely by the claims.

Figur 1

eine Seitenschnittansicht eines Gasturbinentriebwerks;

Figur 2

eine Seitenschnittgroßansicht eines stromaufwärtigen Abschnitts eines Gasturbinentriebwerks;

Figur 3

eine zum Teil weggeschnitte Ansicht eines Getriebes für ein Gasturbinentriebwerk;

Figur 4

den grundlegenden geometrischen Aufbau und die Basisbezeichnungen an einem Verdichtergitter;

Figur 5

schematisch in axialer Schnittdarstellung eine Schaufelradanordnung eines Verdichters eines Gasturbinentriebwerks mit einem stromaufwärtigen Stator, einem Rotor und einem stromabwärtigen Stator;

Figur 6

schematisch einen Schnitt durch das Schaufelrad eines Rotors oder eines Stators gemäß der Figur 5 in einer Ebene senkrecht zur Maschinenachse, wobei das Schaufelrad zwei Bereiche umfasst, die einen unterschiedlichen Schaufeleintrittswinkel und/oder Schaufelaustrittswinkel aufweisen;

Figur 7

eine Schaufelradanordnung gemäß Figur 5, wobei die Schaufeln der einzelnen Schaufelräder jeweils als nominale Schaufeln ausgebildet sind;

Figur 8

eine Schaufelradanordnung gemäß Figur 5, bei der die Schaufeln aller drei Schaufelräder Blöcke ausbilden, die einen unterschiedlichen Schaufel-Staffelungswinkel ausbilden;

Figur 9

eine Schaufelradanordnung gemäß Figur 5, bei der die Schaufeln aller drei Schaufelräder Blöcke ausbilden, die einen unterschiedlichen Schaufeleintrittswinkel oder Schaufelaustrittswinkel aufweisen; und

Figur 10

eine schematische Darstellung der mit der Erfindung erzielten Vorteile unter Darstellung der aerodynamischen Dämpfung in Abhängigkeit vom Knotendurchmesser, wobei bei einer erfindungsgemäßen Schaufelradanordnung die Schaufeln zu Schwingungen angeregt werden, die stärker gedämpft werden;

Figur 11

schematisch eine Strukturbaugruppe, die ein Eintrittsleitrad mit verstellbarem Staffelungswinkel und Teilspalten zu den benachbarten Strömungspfadberandungen aufweist;

Figur 12

ein Eintrittsleitrad gemäß der Figur 11 mit daran ausgebildeten Teilspalten;

Figur 13

in einer Gitterdarstellung ein Beispiel einer Schaufelradanordnung mit einem stromaufwärtigen Eintrittsleitrad, einem Rotor und einem stromabwärtigen Stator, wobei die Schaufeln des Eintrittsleitrads und des Stators jeweils in Blöcken angeordnet sind, die unterschiedlich ausgebildete Teilspalte aufweisen; und

Figur 14

in einer Gitterdarstellung ein Beispiel einer in einen Verdichter eingebetteten Schaufelradanordnung mit einem stromaufwärtigen Stator, einem Rotor und einem stromabwärtigen Stator, wobei die Schaufeln der beiden Statoren jeweils in Blöcken angeordnet sind, die unterschiedlich ausgebildete Teilspalte aufweisen.

The disclosure is explained in more detail below with reference to the figures of the drawing on the basis of several exemplary embodiments. Show it:

Figure 1

a side sectional view of a gas turbine engine;

Figure 2

Fig. 3 is a side sectional close-up view of an upstream portion of a gas turbine engine;

Figure 3

a partially cut away view of a transmission for a gas turbine engine;

Figure 4

the basic geometric structure and the basic designations on a compressor grille;

Figure 5

schematically in an axial sectional illustration a blade wheel arrangement of a compressor of a gas turbine engine with an upstream stator, a rotor and a downstream stator;

Figure 6

schematically a section through the impeller of a rotor or a stator according to FIG Figure 5 in a plane perpendicular to the machine axis, wherein the blade wheel comprises two areas which have a different blade inlet angle and / or blade outlet angle;

Figure 7

a paddle wheel assembly according to Figure 5 wherein the blades of the individual blade wheels are each designed as nominal blades;

Figure 8

a paddle wheel assembly according to Figure 5 in which the blades of all three blades form blocks which form a different blade pitch angle;

Figure 9

a paddle wheel assembly according to Figure 5 in which the blades of all three blade wheels form blocks which have a different blade inlet angle or blade outlet angle; and

Figure 10

a schematic representation of the advantages achieved with the invention, showing the aerodynamic damping as a function of the node diameter, wherein in a paddle wheel arrangement according to the invention, the blades are excited to vibrate, which are more strongly damped;

Figure 11

schematically, a structural assembly which has an inlet guide wheel with an adjustable stagger angle and partial gaps to the adjacent flow path boundaries;

Figure 12

an inlet stator according to FIG Figure 11 with partial gaps formed thereon;

Figure 13

a lattice representation of an example of a fan assembly with an upstream inlet stator, a rotor and a downstream stator, the blades of the inlet stator and the stator being arranged in blocks which have differently formed partial gaps; and

Figure 14

In a lattice representation, an example of an impeller arrangement embedded in a compressor with an upstream stator, a rotor and a downstream stator, the blades of the two stators each being arranged in blocks which have differently designed partial gaps.

It should be noted that the Figures 6 , 8th and 9 do not relate to embodiments of the present invention. They are just non-inventive alternative designs to the actual invention. In addition, the Figures 11-14 not an embodiment of the present invention. In contrast to this the Figures 6 , 8th and 9 can the executions of the Figures 11-14 can be combined with a paddle wheel according to the invention. Indeed, the scope of the invention is defined solely by the claims.

Figure 1 Figure 10 illustrates a gas turbine engine 10 with a main axis of rotation 9. The engine 10 includes an air inlet 12 and a thrust fan 23 that generates two air flows: a core air flow A and a bypass air flow B. The gas turbine engine 10 includes a core 11 which contains the core air flow A. records. The engine core 11 comprises, in axial flow sequence, a low-pressure compressor 14, a high-pressure compressor 15, a combustion device 16, a high-pressure turbine 17, a low-pressure turbine 19 and a core thrust nozzle 20. An engine nacelle 21 surrounds the gas turbine engine 10 and defines a bypass duct 22 and a bypass air flow 18 flows through the bypass duct 22. The fan 23 is attached to the low-pressure turbine 19 via a shaft 26 and an epicycloid gear 30 and is driven by the latter.

In use, the core air flow A is accelerated and compressed by the low pressure compressor 14 and passed into the high pressure compressor 15 where further compression takes place. The compressed air expelled from the high pressure compressor 15 is directed into the combustion device 16, where it is mixed with fuel and the mixture is burned. The resulting hot combustion products then propagate through the high pressure and low pressure turbines 17, 19 and thereby drive them before they pass through the nozzle 20 to provide a certain thrust be expelled. The high pressure turbine 17 drives the high pressure compressor 15 through a suitable connecting shaft 27. The fan 23 generally provides the majority of the thrust. The epicycloidal gear 30 is a reduction gear.

An exemplary arrangement for a geared fan gas turbine engine 10 is shown in FIG Figure 2 shown. The low pressure turbine 19 (see Figure 1 ) drives the shaft 26, which is coupled to a sun gear 28 of the epicycloidal gear assembly 30. Several planet gears 32, which are coupled to one another by a planet carrier 34, are located radially outward from the sun gear 28 and mesh with it. The planet carrier 34 constrains the planet gears 32 to orbit synchronously about the sun gear 28 while allowing each planet gear 32 to rotate about its own axis. The planet carrier 34 is coupled to the fan 23 via linkage 36 to drive its rotation about the engine axis 9. An outer gear or ring gear 38, which is coupled to a stationary support structure 24 via linkage 40, is located radially outward from the planet gears 32 and meshes with them.

It is noted that the terms "low-pressure turbine" and "low-pressure compressor" as used herein can be understood to mean the turbine stage with the lowest pressure and the compressor stage with the lowest pressure (ie that it is not the fan 23) and / or the turbine and compressor stages which are connected to one another by the connecting shaft 26 with the lowest speed in the engine (ie that it does not include the transmission output shaft which drives the fan 23). In some documents, the "low pressure turbine" and "low pressure compressor" referred to herein may alternatively be known as the "medium pressure turbine" and "medium pressure compressor". Using such alternative nomenclature, the fan 23 may be referred to as a first compression stage or compression stage with the lowest pressure.

The epicycloidal gear 30 is shown in Figure 3 shown in more detail as an example. The sun gear 28, planet gears 32 and ring gear 38 each include teeth around their periphery for meshing with the other gears. However, for the sake of clarity, only exemplary sections of the teeth are shown in FIG Figure 3 shown. Although four planet gears 32 are shown, it will be apparent to those skilled in the art that more or fewer planet gears 32 can be provided. Practical applications of an epicycloidal gear 30 generally include at least three planet gears 32.

This in Figure 2 and 3 The epicycloidal gear 30 shown as an example is a planetary gear in which the planet carrier 34 is coupled to an output shaft via linkage 36, the ring gear 38 being fixed. However, a any other suitable type of epicycloidal gear 30 can be used. As another example, the epicycloidal gear 30 may be a star configuration in which the planet carrier 34 is held in place while allowing the ring gear (or outer gear) 38 to rotate. With such an arrangement, the fan 23 is driven by the ring gear 38. As another alternative example, the transmission 30 may be a differential gear that allows both the ring gear 38 and the planet carrier 34 to rotate.

It goes without saying that the in Figure 2 and 3 The arrangement shown is exemplary only and various alternatives are within the scope of the present disclosure. Any suitable arrangement for positioning the transmission 30 in the engine 10 and / or for connecting the transmission 30 to the engine 10 can be used merely as an example. As another example, the links (e.g., the linkages 36, 40 in the example of FIG Figure 2 ) have some degree of rigidity or flexibility between the transmission 30 and other parts of the engine 10 (such as the input shaft 26, the output shaft, and the fixed structure 24). As another example, any suitable arrangement of the bearings between rotating and stationary parts of the engine (e.g., between the input and output shafts of the transmission and the fixed structures such as the transmission housing) can be used and the disclosure is not to the exemplary arrangement of Figure 2 limited. For example, it is readily apparent to a person skilled in the art that the arrangement of output and support rods and bearing positioning in a star arrangement (described above) of the transmission 30 generally differs from those exemplified in FIG Figure 2 would differ.

Accordingly, the present disclosure extends to a gas turbine engine having any arrangement of gear types (e.g., star or planetary), support structures, input and output shaft arrangements, and bearing positions.

Optionally, the transmission can drive secondary and / or alternative components (e.g. the medium-pressure compressor and / or a booster).

Other gas turbine engines to which the present disclosure may find application may have alternative configurations. For example, such engines can have an alternative number of compressors and / or turbines and / or have an alternative number of connecting shafts. As another example, the Figure 1 The gas turbine engine shown has a split flow nozzle 20, 22, which means that the flow through the bypass duct 22 has its own nozzle which is separate from the engine core nozzle 20 and radially outward therefrom. However, this is not limiting and any aspect of the present disclosure may also apply to engines in which the flow through the bypass duct 22 and the flow through the core 11 are before (or upstream) a single nozzle, which can be referred to as a mixed flow nozzle, mixed or combined. One or both nozzles (whether mixed or split flow) can have a fixed or variable range. For example, while the example described relates to a turbo fan engine, the disclosure may be applied to any type of gas turbine engine such as a gas turbine engine. B. in an open rotor (in which the fan stage is not surrounded by an engine nacelle) or a turboprop engine. In some arrangements, the gas turbine engine 10 may not include a gearbox 30.

The geometry of the gas turbine engine 10 and components thereof is or are defined by a conventional axis system which includes an axial direction (which is aligned with the axis of rotation 9), a radial direction (in the direction from bottom to top in Figure 1 ) and a circumferential direction (perpendicular to the view in Figure 1 ) includes. The axial, radial and circumferential directions are perpendicular to one another.

In the context of the present invention, the design of the impellers is particularly important in the compressor. The invention can basically be used in a low-pressure compressor, a medium-pressure compressor (if present) and / or a high-pressure compressor.

First of all, the Figure 4 the basic structure of a compressor grille is described. The compressor grille is shown in the usual representation in meridional section and unrolled. It comprises a plurality of blades S, each of which has a leading edge S _VK and a trailing edge S _HK . The front edges S _VK lie on an imaginary line L ₁ , the rear edges S _HK lie on an imaginary line L ₂ . The lines L ₁ and L ₂ run parallel. The blades S furthermore each include a suction side SS and a pressure side DS. Their maximum profile thickness is indicated by d.

The compressor grid has a grid division t and a profile chord s with a profile chord length s _k . The profile chord s is the line connecting the Front edge S _VK and the rear edge S _{HK of} the profile. _{The blade stagger angle (hereinafter stagger angle) α s is} formed between the profile chord s and the vertical on the line L ₁ (the vertical at least approximately corresponds to the direction defined by the machine axis). The stagger angle α _s indicates the inclination of the blades S.

The blades S have a skeleton line SL, which is also referred to as the profile center line. This is defined by the line connecting the circle centers inscribed in the profile. The tangent to the skeleton line SL at the front edge is denoted _{by T 1.} The tangent to the skeleton line SL at the rear edge is denoted _{by T 2.} The angle at which the two tangents T ₁ , T ₂ intersect is the blade curvature angle A. The direction of inflow with which gas flows towards the grille is Z and the direction of outflow, with which gas flows away from the grille, is D. marked. The angle of incidence β ₁ is defined as the angle between the tangent T ₁ and the inflow direction Z. The deviation _{angle β 2} is defined as the angle between the tangent T ₂ and the outflow direction A.

In the context of the present invention, the blade inlet angle γ ₁ and the blade outlet angle γ _{2 are} of particular importance. The blade outlet _{angle γ 1} is defined as the angle between the tangent T ₁ to the skeleton line SL and the perpendicular on the line L ₁ . The blade outlet _{angle γ 2} is defined as the angle between the tangent T ₂ to the skeleton line SL and the perpendicular on the line L ₂ . The blade _{inlet angle γ 1} is also referred to as the blade inlet angle or as the inflow metal angle and the blade outlet angle γ ₂ is also referred to as the blade outlet angle or as the outflow metal angle.

The blade _{inlet angle γ 1} and the blade _{outlet angle γ 2} both change if the stagger angle α _{s is changed} while the shape of the blades remains the same, since a change in the stagger angle α _s in such a case changes the alignment of the tangents T _{1 due to the associated inclination adjustment of the blades} , T ₂ changed. By changing the curvature of the blades S, however, the blade _{inlet angle γ and / or the blade outlet angle γ 2} can also be changed without changing the stagger angle α _s . It can also be provided that by appropriate shaping of the blades S only the blade _{inlet angle γ 1} or the blade _{outlet angle γ 2 is} changed, this also leading to a change in the stagger angle α _s .

the Figure 5 shows an impeller arrangement for a compressor, which has a first impeller 6, which is designed as an impeller. Upstream of the impeller 6, a second impeller 5 is arranged, which is designed as a stator. Furthermore, a third impeller 7, which is designed as a further stator, is arranged downstream of the impeller 6. The upstream stator 5 can be designed as an inlet stator (IGV). However, this is not necessarily the case. It can also be a normal compressor stator of a stage embedded in the compressor. A flow path 8 of the compressor or the core engine extends through the impeller arrangement.

Each of these impellers 5, 6, 7 comprises a plurality of blades which extend radially in the flow path 8 of the turbomachine. It is provided that the blades are divided into blocks on at least one of the blade wheels 5, 6, 7, for which it applies that the blades within a block each have the same blade inlet angle and the same blade outlet angle. In contrast, the blades of at least two adjacent blocks have a different blade inlet angle and / or a different blade outlet angle.

This is exemplified and schematically based on the Figure 6 illustrated. the Figure 6 shows a paddle wheel in a cross section transverse to the machine axis showing the polar coordinates r, ϕ, which is one of the paddle wheels 5, 6, 7 of the Figure 5 can act. The individual blades are not shown separately. The paddle wheel is divided into two blocks B1, B2. Each of the blocks extends in the circumferential direction ϕ over an extension angle δ of 180 °. According to the invention, the paddle wheel is subdivided into a larger number of blocks, the following applies to the extension angle δ: δ = 360 ° / N where N indicates the number of blocks and a natural number is greater than 2.

The blades of the blocks B1, B2 have a different blade inlet angle and / or a different blade outlet angle.

the Figure 6 FIG. 11 also shows an alternative exemplary embodiment in which the individual blocks B1, B2 have a different extension angle in the circumferential direction exhibit. One block B1 has an extension angle δ1 less than 180 ° and block B2 has an extension angle which is correspondingly greater than 180 °. According to the invention, the paddle wheel is subdivided into a larger number of blocks, the individual blocks each being able to have a different extension angle and accordingly a different number of blades.

Based on Figures 7 to 9 two exemplary embodiments are explained in which the blade wheels form blocks with different blade inlet angles and / or different blade outlet angles. the Figure 7 shows initially a nominal position of the blades, with all blades having the same blade inlet angle and the same blade outlet angle. The illustrated impeller arrangement comprises a rotor or an impeller 6, which has a plurality of rotor blades 60 which rotate in a direction F. The blades 60 of the impeller 6 form a row of blades.

A stator or a stator 5, which has a plurality of stator blades 50, is arranged upstream of the impeller 6. Furthermore, a stator or a stator 7, which has a plurality of guide vanes 70, is arranged downstream of the impeller 6. The direction of flow with which the gas flows towards the stator 5 is indicated by the arrow E. All the blades of the paddle wheels 5, 6, 7 are in the Figure 7 shaped and aligned in an identical manner.

the Figure 8 shows a first embodiment of a deviating paddle wheel arrangement. First, the stator 5 is considered. This has N blocks of blades, blades of two blocks, namely the blocks B _j and B _{k being} shown. The individual blocks include in the representation of the Figure 8 two shovels each. This is only to be understood as an example. The individual blocks B _j and B _k can also have a larger number of blades, the blades being subdivided into at least N = 2 blocks overall. Can also Figure 8 should be understood to mean that not all blades of a block are shown, i.e. further blades of block B _{j are connected above the top blade in the drawing and further blades of block B k are} connected below the lowest blade in the drawing, with Figure 8 only the transition between the two blocks B _j and B _{k is} shown.

the Figure 8 shows both the blades 50 in the nominal position corresponding to FIG Figure 7 as well as the blades in a changed position. The shovels in the changed position are marked _{with 51 in block B j} and 52 in block B _k. It is the case that the blades 51, 52 of the two blocks B _j and B _{k have} a different stagger angle. The stagger angle is the stator 5 (the second impeller S2 the Figure 5 ) defined as follows: $${\mathrm{\alpha }}_{\mathrm{S.}2,\mathrm{i}}={\mathrm{\alpha }}_{\mathrm{S.}2.0}+{\left(-1\right)}^{\mathrm{i}}\Delta {\mathrm{\alpha }}_{\mathrm{S.}2}$$

Α _{S2,0 is} a constant that defines the nominal graduation angle according to the Figure 7 indicates. The following applies to i: 1 ≤ i ≤ N. The staggering angle is adjusted from the nominal position in one direction or in the other direction by the amount of change Δα _S2. In the case of the blades of adjacent blocks B _j and B _k , the stagger angle is changed with a different sign. Thus, there is a change in the stagger angle between the blades 50 and the blades 51 of the block B _j by the amount of change -Δα _S2 , as in FIG Figure 5 is indicated. Between the blades 50 and the blades 52 of the block B _{k there} is a change in the stagger angle by the amount of change + Δα _S2 . The staggering angle is the same as in relation to the Figure 4 explained defined.

The change in the staggering angle in the individual blocks is accompanied by the fact that, compared to the nominal position in block B _j, the stator blades are more closed and more open _{in block B k.}

In the exemplary embodiment shown, but not necessarily, modifications have also been made to the stagger angle for the impeller 6 and the stator 7. First of all, the further stator 7 is considered. This is divided into the same number N of blocks, each with a different graduation angle.

the Figure 8 FIG. 7 shows both the blades 70 in the nominal position corresponding to FIG Figure 7 as well as the blades in a modified position. The blades in the modified position are marked _{with 71 in block B j} and 72 in block B _k. The situation is that the blades 71, 72 of the two blocks B _j and B _{k have} a different stagger angle. The staggering angle is the stator 7 (the third impeller S3 the Figure 5 ) defined as follows: $${\mathrm{\alpha }}_{\mathrm{S3},\mathrm{i}}={\mathrm{\alpha }}_{\mathrm{S3},0}-{\left(-1\right)}^{\mathrm{i}}\Delta {\mathrm{\alpha }}_{\mathrm{S3}}$$

In this case, α _{S3,0 is} a constant that defines the nominal graduation angle according to the Figure 7 concerns. The following applies to i: 1 i N. The explanations for the stator 5 apply accordingly. Thus, there is a change in the stagger angle between the blades 70 and the blades 71 of the block B _j by the amount of change + Δα _S3 , as in FIG Figure 5 is indicated. Between the blades 70 and the blades 72 of the block B _{k there} is a change in the stagger angle by the amount of change -Δα _S3 .

The change in sign in the individual blocks of the stator 7 is in the opposite direction than in the blocks of the stator 5. If the stator blades 51 are thus more closed _{in block B j of} the stator 5, the stator blades 71 are stronger _{in block B j of the stator 7} opened. It also applies that if _{the stator blades 52 in block B k} of stator 5 are more open, stator blades 71 in block B _k of stator 7 are more closed.

The amount of change Δα _S3 may be equal to the amount of change Δα _S2 . But this is not necessarily the case.

In the Figure 8 the blades of the impeller 6 are also divided into groups with different stagger angles. However, this is not necessarily the case. In exemplary embodiments of the invention, only the blades of the stator 5 and / or the blades of the stator 7 are divided into groups with different graduation angles. In further exemplary embodiments, it can be provided that only the blades of the impeller 6 are divided into groups with different graduation angles.

the Figure 8 shows both the blades 60 in the nominal position corresponding to FIG Figure 7 as well as the blades in a modified position. The impeller 6 is subdivided into the same number N of blocks, each with a different stagger angle, as the guide wheels 5, 7. The blades in the modified position are marked _{with 61 in block B j} and 62 in block B _k. It is the case that the blades 61, 62 of the two blocks B _j and B _{k have} a different stagger angle. The staggering angle is the impeller 6 (the first impeller S1 Figure 5 ) defined as follows: $${\mathrm{\alpha }}_{\mathrm{S1},\mathrm{i}}={\mathrm{\alpha }}_{\mathrm{S1},0}-{\left(-1\right)}^{\mathrm{i}}\Delta {\mathrm{\alpha }}_{\mathrm{S1}}$$

Α _{S1,0 is} a constant that defines the nominal graduation angle according to the Figure 7 concerns. The following applies to i: 1 i N. The explanations for the stator 5 apply accordingly. Thus, there is a change in the stagger angle between the blades 60 and the blades 61 of the block B _j by the amount of change + Δα _S1 , as in FIG Figure 5 is indicated. Between the blades 60 and the blades 62 of the block B _{k there} is a change in the stagger angle by the amount of change -Δα _S1 .

It should be noted that, as in relation to the Figure 4 explains, a change in the stagger angle α _S with an identical shape of the blades also automatically leads to a change in the blade inlet angle and the blade outlet angle of the blades.

the Figure 9 FIG. 11 shows a second embodiment of one for the arrangement of FIG Figure 7 deviating paddle wheel arrangement. The fundamental difference to the embodiment of the Figure 8 is that in the embodiment of the Figure 9 not the staggering angle (and thus the blade inlet angle and the blade outlet angle if the individual blades are identical), but only the blade inlet angle or the blade outlet angle is changed while providing a different shape of the blades of the different blocks.

First, the stator 5 is considered. This has N blocks of blades, blades of two blocks, namely the blocks B _j and B _{k being} shown. The notes on the size and number of blocks with regard to the Figure 8 apply accordingly to the Figure 9 .

the Figure 9 shows both the blades 50 in the nominal position corresponding to FIG Figure 7 as well as the blades in a changed position. The blades with a modified shape are marked _{with 53 in block B j} and 54 in block B _k. It behaves in such a way that the blades 53, 54 of the two blocks B _j and B _{k have} a different blade inlet angle with an identical blade inlet angle. The blade outlet angle γ _{2 of} the i-th block is the stator 5 (the second blade S2 of the Figure 5 ) defined as follows: $${\mathrm{\gamma }}_{\mathrm{2}\mathrm{,\; S2}\mathrm{,\; i}}={\mathrm{\gamma }}_{\mathrm{2}\mathrm{,\; S2}\mathrm{,\; 0}}+{\left(-1\right)}^{\mathrm{i}}\Delta {\mathrm{\gamma }}_{\mathrm{2}\mathrm{,\; S2}}$$

Here, γ _{2, S2,0 is} a constant that defines the nominal blade outlet angle according to Figure 7 indicates. The following applies to i: 1 ≤ i ≤ N. From the nominal position, the becomes Blade outlet angle adjusted in one direction or in the other direction by the amount of change Δγ _{2, S2.} In the case of the blades of adjacent blocks B _j and B _k , the blade exit angle is changed with different signs. Thus, there is a change in the blade outlet angle between the blades 50 and the blades 53 of the block B _j by the amount of change -Δγ _{2, S2} , as in FIG Figure 5 is indicated. Between the blades 50 and the blades 54 of the block B _{k there} is a change in the blade outlet angle by the amount of change + Δγ _{2, S2} . The blade outlet angle is the same as in relation to the Figure 4 explained defined.

The change in the blade exit angle in the individual blocks is associated with the fact that the stator blades are more closed _{in block B j} and more open _{in block B k.}

In the exemplary embodiment shown, but not necessarily, modifications have also been made to the stagger angle for the impeller 6 and the stator 7. First of all, the further stator 7 is considered. This is divided into the same number N of blocks, each with a different graduation angle.

the Figure 9 FIG. 7 shows both the blades 70 in the nominal position corresponding to FIG Figure 7 as well as the blades in a modified position. The blades with a modified shape are marked _{with 73 in block B j} and 74 in block B _k. It behaves in such a way that the blades 73, 74 of the two blocks B _j and B _{k have} a different blade outlet angle with an identical blade inlet angle. The blade outlet angle γ _{2 of} the i-th block is at the stator 7 (the third blade S3 of the Figure 5 ) defined as follows: $${\mathrm{\gamma }}_{\mathrm{2}\mathrm{,\; S3}\mathrm{,\; i}}={\mathrm{\gamma }}_{\mathrm{2}\mathrm{,\; S3}\mathrm{,\; 0}}+{\left(-1\right)}^{\mathrm{i}}\Delta {\mathrm{\gamma }}_{\mathrm{2}\mathrm{,\; S3}}$$

Here, γ _{2, S3,0 is} a constant that defines the nominal blade outlet angle according to Figure 7 indicates. The following applies to i: 1 i N. From the nominal position, the blade outlet angle is adjusted _{in one direction or in the other direction by the amount of change Δγ 2, S3.} In the case of the blades of adjacent blocks B _j and B _k , the blade exit angle is changed with different signs. There is thus a change in the blade outlet angle between the blades 70 and the blades 73 of the block B _j by the amount of change + Δγ _{2, S3} . Between the blades 70 and the blades 74 of the block B _{k there} is a change in the blade outlet angle by the amount of change -Δγ _{2, S3} .

The change in sign in the individual blocks of the stator 7 is in the opposite direction than in the blocks of the stator 5. If the stator blades 51 are thus more closed _{in block B j of} the stator 5, the stator blades 71 are stronger _{in block B j of the stator 7} opened. It also applies that if _{the stator blades 52 in block B k} of stator 5 are more open, stator blades 71 in block B _k of stator 7 are more closed.

In the Figure 9 the blades of the impeller 6 are also divided into groups with different blade inlet angles, although this is not necessarily the case. It can also be provided in one embodiment that only the blades of the impeller 6 are divided into groups with different blade entry angles.

the Figure 9 shows both the blades 60 in the nominal position corresponding to FIG Figure 7 as well as the blades with a modified shape. The impeller 6 is divided into the same number N of blocks as the other paddle wheels 5, 7. The blades in the modified shape are marked _{with 61 in block B j} and 62 in block B _k. It behaves in such a way that the blades 61, 62 of the two blocks B _j and B _{k have} a different blade inlet angle with an identical blade exit angle. The blade entry angle γ _{1 of} the i-th block is the impeller 6 (the first impeller S1 the Figure 5 ) defined as follows: $${\mathrm{\gamma }}_{1,\mathrm{S.}1,\mathrm{i}}={\mathrm{\gamma }}_{1,\mathrm{S.}1.0}+{\left(-1\right)}^{\mathrm{i}}\Delta {\mathrm{\gamma }}_{1,\mathrm{S.}1}$$

Here, γ _{1, S1,0 is} a constant that defines the nominal blade inlet angle according to Figure 7 indicates. The following applies to i: 1 i N. From the nominal position, the blade outlet angle is adjusted _{in one direction or in the other direction by the amount of change Δγ 1, S1.} In the case of the blades of adjacent blocks B _j and B _k , the blade entry angle is changed with a different sign. There is thus a change in the blade inlet angle between the blades 60 and the blades 63 of the block B _j by the amount of change + Δγ _{1, S1} . Between the blades 60 and the blades 64 of the block B _{k there} is a change in the blade outlet angle by the amount of change -Δγ _{1, S1} .

Only a paddle wheel with an angular position of the blades according to claim 1 is a paddle wheel according to the invention.

Based on Figures 11-14 Another exemplary embodiment is described in which the blades of a blade wheel are likewise subdivided into a plurality of blocks, the blades being of identical design within a block are. The property in which the individual blocks differ, however, is different than in the exemplary embodiments of FIG Figures 4-9 not the blade inlet angle and / or the blade outlet angle, but rather lies in the configuration of partial gaps which the blades form towards the respective adjoining flow path boundary. With regard to the division of the paddle wheel into individual blocks, the remarks on Figures 4-9 corresponding way.

the Figure 11 shows a sectional view of a structural assembly that defines a flow path 8 and comprises a stator 5, a rotor 6 of a compressor stage of a compressor and flow path boundaries. The stator 5 is designed as an inlet stator, although this is not necessarily the case. The flow path 8 guides the core air flow A according to FIG Figure 1 through the core engine.

The flow path 8 is delimited radially on the inside by a hub 95 which forms an inner flow path boundary 950. The flow path 8 is delimited radially on the outside by a compressor housing 4 that forms a radially outer flow path boundary 410. The flow path 8 is designed as an annular space. The inlet guide wheel 5 has stator blades or guide blades 55 which are adjustable in the staggering angle and which are distributed in the circumferential direction in the flow path 8. The guide vanes 55 each have a leading edge 551 and a trailing edge 552.

The swirl in the flow is increased by the inlet guide wheel 5, and the following rotor 6 is thus aimed at in a more effective manner. The rotor 6 comprises a row of rotor blades or rotor blades 60, which extend radially in the flow path 8.

The guide vanes 55 are rotatably mounted so that the stagger angle can be adjusted. For this purpose, they are each connected in a rotationally fixed manner to a spindle 25 or formed integrally with such a spindle. The spindle 25 has an axis of rotation which is the same as the axis of rotation of the guide vane 55. The spindle 25 is accessible and adjustable from outside the flow path 8.

Specifically, it is provided that the guide vane 55 is connected at its radially outer end to an outer circular platform 75 which forms a turntable and is connected to a radially outer spindle section 251 of the spindle 25. The platform 75 and the spindle section 251 are mounted in a housing cover band 420 which is part of the compressor housing 4. In a corresponding way is the Guide vane 55 is connected at its radially inner end to an inner circular platform 78, which forms a further turntable and is connected to a radially inner spindle section 252 of spindle 25. The platform 78 and the spindle section 252 are supported in an inner shroud 910 which locally forms the inner flow path boundary 950.

In order to enable the guide vanes 55 to rotate or the stagger angle to be adjusted, it is necessary for the guide vanes 55 to form cutbacks 553, 554 in the region of their trailing edge 552 radially adjacent to the outer flow path boundary 410 and radially adjacent to the inner flow path boundary 950 that the guide vanes 55 each form a partial gap 81 to the radially outer flow path boundary 410 and a partial gap 82 to the radially inner flow path boundary 950 in their axially rearward region. This prevents the stator blade 55 from colliding with the outer flow path boundary 410 and / or with the inner flow path boundary 950 when the guide vane 55 is adjusted by rotating about the axis of rotation.

The gaps 81, 82 are referred to as partial gaps, since they do not extend over the entire axial length of the guide vanes 55.

Alternatively, it can be provided that the guide vanes 55 are designed without a shroud at their radially inner end, in which case they end freely floating with the formation of a continuous gap radially spaced apart from the inner flow path boundary 95. Alternatively, it can also be provided that partial gaps are formed in the area of the front edge 51 or both in the area of the front edge 51 and in the area of the rear edge 52.

the Figure 12 shows the arrangement of guide vane 55, outer and inner platform 75, 78 and spindle 25 of FIG Figure 11 in an enlarged view. The cutbacks 553, 554 create the partial gaps 81, 82 to the outer and inner flow path boundaries. The partial gaps 81, 82 have a gap volume which is defined by the axial length and the radial height of the partial gaps 81, 82 or the recesses 553, 554 forming them.

To vary the partial gap 81 and / or the partial gap 82 in different blocks that form the guide vanes 55 of the stator 5, the radial height r of the partial gap and / or the axial length x of the partial gap can be varied. In the Figure 12 are as The dashed line shows two variations V1, V2 of the partial columns 81, 82. The first variation V1 is made on the upper partial gap 81, it being possible alternatively or simultaneously for the lower partial gap 82 as well. Thereafter, the radial height of the partial gap 81 is increased in that the cutback 553 'is made deeper. The second variation V2 is made on the lower partial gap 82, it being possible, alternatively or simultaneously, to also take place in the upper partial gap 81. Thereafter, the axial length of the partial gap 81 is increased in that the diameter of the lower platform 78 is reduced and at the same time the cutback 554 has a greater axial length.

The variations shown can also be combined, i. H. the upper partial gap 81 and / or the lower partial gap 82 are varied by a changed axial length and a changed radial height.

Based on Figures 13 and 14th In the following, two exemplary embodiments are explained in which the paddle wheels form blocks with differently configured partial gaps. The basic arrangement corresponds to that of Figure 5 , wherein an impeller arrangement for a compressor comprises a rotor 6, a variable stator 5 arranged upstream of the rotor 6 and a variable stator 7 arranged downstream of the rotor 6. In the Figure 13 the upstream stator 5 is an inlet stator. In the Figure 14 a sequence of stator 5, rotor 6 and stator 7 embedded in a compressor is shown.

Referring to the Figure 13 the inlet guide wheel 5 is considered first. This has N blocks of blades, blades of two blocks, namely the blocks B _j and B _{k being} shown. The individual blocks include in the representation of the Figure 13 two blades 56, 57 in each case. This is only to be understood as an example. The individual blocks B _j and B _k can also have a larger number of blades, the blades being subdivided into at least N = 2 blocks overall. Can also Figure 13 should be understood to mean that not all blades of a block are shown, i.e. further blades of block B _{j are connected above the top blade in the drawing and further blades of block B k are} connected below the lowest blade in the drawing, with Figure 13 only the transition between the two blocks B _j and B _{k is} shown.

The blocks B _j and B _k differ in the partial gaps which the blades 56, 57 form with respect to the adjoining flow path boundary. Thus, the partial gaps 811 of the blades 56 of the block B _{j of} the inlet stator 5 have a larger axial direction Extension to as the partial column 812 of the blades 57 of the block B _k . The gap area covered by the partial gaps 811 is accordingly larger than the gap area covered by the partial gaps 812.

In the exemplary embodiment shown, but not necessarily, modifications are also implemented in the partial gaps in the stator 7. This is subdivided into the same number N of blocks B _j and B _k , each with differently designed partial gaps for the outer flow path boundary and / or for the inner flow path boundary. Alternatively, modifications in the partial columns are only implemented in the case of the stator 7.

The partial gaps 813 of the blades 76 of the block B _{j of} the stator 7 have a smaller axial extent than the partial gaps 814 of the blades 77 of the block B _k . The gap area covered by the partial gaps 813 is accordingly smaller than the gap area covered by the partial gaps 814. The assignment of the partial gaps between the blocks of the inlet guide wheel 5 and the blocks of the stator 7 is offset, ie blocks with larger partial gaps 811 of the inlet guide wheel 5 are assigned to blocks 813 with smaller partial gaps 813 of the stator 7 and vice versa.

In the Figure 13 and also in the Figure 14 The section of the illustration takes place directly adjacent to the radially outer flow path boundary 410. Sub-gaps are thus formed in the areas 811, 812, 813, 814. Correspondingly, partial gaps can additionally be formed adjacent to the radially inner flow path boundary 950 or only adjacent to the radially inner flow path boundary 950, cf. Figure 11 .

It is further pointed out that the partial gaps 811, 812, 813, 814 also have a radial variation, as is shown schematically in FIG Figure 12 shown, may have. In the sectional view of the Figures 13 and 14th such a radial variation cannot be seen.

Another variation can be that the partial gaps are not implemented in the area of the trailing edge of the blades, but in the area of the leading edge of the blades, or both in the area of the trailing edge and in the area of the leading edge of the blades.

the Figure 14 shows in the blade profile a blade wheel arrangement which comprises two variable stators 5, 7 embedded in a compressor and a rotor 6 arranged between them.

The inlet guide wheel 5 has N blocks of blades, blades of two blocks, namely the blocks B _j and B _{k being} shown. The individual blocks include in the representation of the Figure 14 two blades 58, 59 each. With regard to the size of the individual blocks B _j and B _k , the statements relating to Figure 13 in a corresponding manner. The blocks B _j and B _k differ in the partial gaps which the blades 58, 59 form with respect to the adjoining flow path boundary. Thus, the partial gaps 815 of the blades 58 of the block B _{j of} the stator 5 have a smaller axial extent than the partial gaps 816 of the blades 59 of the adjacent block B _k . The gap area covered by the partial gaps 815 is accordingly smaller than the gap area covered by the partial gaps 816.

In the illustrated embodiment, but not necessarily, modifications are also implemented in the partial columns in the stator 7. This is subdivided into the same number N of blocks B _j and B _k , each with differently designed partial gaps for the outer flow path boundary and / or for the inner flow path boundary. Alternatively, modifications in the partial columns are only implemented in the case of the stator 7.

The stator 7 is in the same way as the stator 7 of Figure 13 educated. The partial gaps 813 of the blades 76 of the block B _{j of} the stator 7 have a smaller axial extent than the partial gaps 814 of the blades 77 of the block B _k . The gap area covered by the partial gaps 813 is accordingly smaller than the gap area covered by the partial gaps 814. The assignment of the partial gaps between the blocks of the inlet guide wheel 5 and the blocks of the stator 7 is such that blocks with smaller partial columns 815 of the stator 5 are assigned to blocks 813 with smaller partial columns 813 of the stator 7 and blocks with larger partial columns 816 of the stator 5 are assigned to blocks with larger partial columns 814 of the stator 7 are assigned.

The in relation to the embodiment of Figure 13 The variants explained apply in a corresponding manner to the exemplary embodiment in FIG Figure 14 .

It is further pointed out that the embodiments of the Figures 11-14 with the designs of Figures 3-9 can be combined. The individual blocks of blades that form a blade wheel can thus be both with regard to the Differentiate blade inlet angle and / or blade outlet angle or the stagger angle as well as with regard to the design of the partial gaps.

the Figure 10 shows schematically the advantages achieved by the present invention. The aerodynamic damping is given as a function of the node diameter. First of all, it should be noted that the rows of blades form cyclic overall oscillation forms that are characterized by nodal lines. The maximum number of nodal lines is equal to half of the blades with an even number of blades and half of the blades minus one with an odd number of blades. The deflection is zero in a nodal line.

The knot diameter is determined by the knot pattern. In the Figure 10 the bar X1 shows oscillation excitations without implementation of the invention and the bar X2 shows oscillation excitations with implementation of the invention. The invention has resulted in a different knot pattern in which the aerodynamic damping is increased, so that the build-up of a rotating tear-off is effectively prevented.

It should be understood that the disclosure is not limited to the embodiments described above, and various modifications and improvements can be made without departing from the concepts described herein. For example, it can be provided that the individual blocks realize more than two different blade inlet angles and / or blade outlet angles, so that, for example, a total of 6 blocks are provided, two of which have a first blade inlet angle and / or blade outlet angle, and two others have a second blade inlet angle and / or blade outlet angle have, and two others have a third blade inlet angle and / or blade outlet angle. In further exemplary embodiments, it can be provided that the blade inlet angle and / or blade outlet angle between adjacent blocks does not change discretely, but rather continuously, for example in accordance with the shape of a sinusoid.

It is further pointed out that in the case of a discrete change, an identical deviation of the angle under consideration from the nominal position, only differing in sign, is only to be understood as an example. Alternatively, it can be provided that the change angle in one direction does not necessarily correspond to the change angle in the other direction.

It should be noted that any of the features described can be used separately or in combination with any other features, provided that they are not mutually exclusive. The disclosure extends to and includes all combinations and subcombinations of one or more features described herein. If areas are defined, these include all values within these areas as well as all sub-areas that fall into one area.

The scope of protection of the invention is defined solely by a paddle wheel with the features of claim 1 and a paddle wheel arrangement with the features of claim 6. Refinements of the invention are given in the dependent claims.

Claims (9)

1. Blade wheel of an axial turbomachine, which blade wheel has:

   - a multiplicity of blades (51-54, 61-64, 71-74) which form a blade row and are suitable and provided for extending radially in a flow path (8) of the axial turbomachine, wherein

   - the blades (51-54, 61-64, 71-74) form a blade entry angle (γ₁) and a blade exit angle (γ₂), and

   - the multiplicity of blades (51-54, 61-64, 71-74) form N blocks (B1, B2; B_j, B_k) of blades, where N > 2, wherein

   o the blades (51-54, 61-64, 71-74) of a block (B1, B2; B_j, B_k) have in each case the same blade entry angle (γ₁) and the same blade exit angle (γ₂), and

   o the blades (51-54, 61-64, 71-74) of at least two mutually adjacent blocks (B1, B2; B_j, B_k) have a different blade entry angle (γ₁) and/or a different blade exit angle (γ₂),

   characterized in that,
   for the angular position of the blades (51-54, 61-64, 71-74) of the individual blocks, the following applies: $${\phi }_l={\phi }_0+{\displaystyle {\sum }_{k=1}^N{a}_k\cos }\left(\frac{2\mathit{k\pi }}{N}l\right)+b_k\sin \left(\frac{2\mathit{k\pi }}{N}l\right)$$

   

   
   where

   - ϕ is the blade entry angle, the blade exit angle or the stagger angle of the blades of a block under consideration;

   - a_k, b_k are freely selectable coefficients that lie in the range [-10°, 10°];

   - the index "l" denotes the number of the block under consideration;

   - N denotes the total number of blocks, where N>2;

   - the index "k" denotes the running index of the coefficients, where k = 1, ..., N;

   - ϕ₀ is the mean angle that is set;
   and where, for the coefficients a_k, b_k, it is the case that, for at least two values of the index "k", it is the case that not both coefficients a_k, b_k are equal to zero.
2. Blade wheel according to Claim 1, characterized in that the blades (51-52, 61-62, 71-72) of at least two mutually adjacent blocks (B1, B2; B_j, B_k) have a different blade entry angle (γ₁) and a different blade exit angle (γ₂) by virtue of the fact that the blades of the blocks (B1, B2; B_j, B_k), in the case of identical shaping of the blades (51-52, 61-62, 71-72), form a different stagger angle α_s.
3. Blade wheel according to Claim 1 or 2, characterized in that the blades (54-54, 63-64, 73-74) of at least two mutually adjacent blocks (B1, B2; B_j, B_k) have a different blade entry angle (γ₁) or a different blade exit angle (γ₂) by virtue of the fact that the blades of the blocks (B1, B2; B_j, B_k) have a different shape.
4. Blade wheel according to any of the preceding claims, characterized in that at least two of the blocks (B1, B2) have a different extent angle (δ1) in a circumferential direction, wherein the blocks with different extent angle have a different number of blades.
5. Blade wheel according to any of the preceding claims, characterized in that the blades of a block (B1, B2; B_j, B_k) are opened in relation to a nominal blade setting and the blades of an adjacent block (B1, B2; B_j, B_k) are closed in relation to the nominal blade setting.
6. Blade wheel arrangement for a compressor of a turbomachine, which blade wheel arrangement has:

   - a first blade wheel (6), which is formed as a rotor,

   - a second blade wheel (5), which is arranged upstream of the first blade wheel (6) and which is formed as a stator, and

   - a third blade wheel (7), which is arranged downstream of the first blade wheel (6) and which is formed as a stator,
   characterized in that
   at least one of the blade wheels (4, 5, 6) is formed as a blade wheel according to Claim 1.
7. Blade wheel arrangement according to Claim 6, characterized in that the second blade wheel (5) and the third blade wheel (7) are formed as blade wheels according to Claim 1, wherein the two blade wheels (5, 7) form the same number of N blocks (B1, B2; B_j, B_k) of blades (51-54, 71-74), where N > 2, and wherein a block (B_j, B_k) of the second blade wheel (5), in which the blades of the block are closed to a greater degree in relation to a first nominal blade setting, is assigned a block (B_j, B_k) of the third blade wheel (7), in which the blades of the block are opened to a greater degree in relation to a second nominal blade setting.
8. Blade wheel arrangement according to Claim 6, characterized in that the first blade wheel (6) is formed as a blade wheel according to Claim 1.
9. Blade wheel arrangement according to any of Claims 6 to 8, characterized in that the second blade wheel (5) formed as a stator is formed as an inlet stator.

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