EP2158404A1

EP2158404A1 - Nose dome for a turbomachine rotor

Info

Publication number: EP2158404A1
Application number: EP08760534A
Authority: EP
Inventors: Thomas MÖNK; Axel Spanel; Wolfgang Zacharias
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2007-06-27
Filing date: 2008-06-05
Publication date: 2010-03-03
Also published as: WO2009000618A1; US8545174B2; CN101688542A; CN101688542B; EP2009290A1; US20100183432A1

Abstract

A nose dome for a turbomachine rotor, which turbomachine rotor has an impeller which is arranged in a floating fashion with respect to a bearing point of the turbomachine rotor, can be connected axially to the impeller in order to guide an axial inflow and/or outflow of said impeller, and has a coupling device, by means of which the impeller and the nose dome can be mechanically coupled radially, such that the vibration behaviour of the turbomachine rotor can be influenced. The turbomachine with the turbomachine rotor has the nose dome, wherein the impeller and the nose dome are coupled radially by means of the coupling device, such that the vibration of the turbomachine rotor is damped.

Description

description

Nose hood for a turbomachine rotor

The invention relates to a nose hood for a

A turbomachine rotor and a turbomachine having a turbomachine rotor having the nose hood.

A turbomachine is, for example, a conventional turbocompressor 101 as shown in FIGS. 8 and 9. The turbocompressor 101 has a housing 102 and a turbocompressor rotor 103 surrounded by the housing 102. The turbo compressor rotor 103 has a shaft 104 which is supported on a bearing 105 on the housing 102. Further, the turbo compressor rotor 103 has an impeller

106, which is arranged to fly to the bearing 105. The impeller 106 is a radial compressor impeller whose inflow in the axial direction of the shaft 104 and its outflow in the radial direction of the shaft 104 extends. The inflow is guided in an inlet channel 107 of the turbocompressor 101 running in the axial direction of the shaft 104, so that the inflow into the shaft 106 in the axial direction of the shaft 104 hits the impeller 106. In order to manipulate the inflow, for example for impinging the inflow with swirl, a plurality of adjustable guide vanes 108 is arranged in the inlet passage 107, wherein the adjustable guide vanes 108 are combined to form a blade ring.

As shown in Fig. 8, the hub portion is the

Leitschaufel 108 provided with a nose hood 110 which is fixed to the impeller 106 and thus rotates with the impeller 106 with. The nose cap 110 is aerodynamically shaped and serves to minimize the interference of the hub portion of the impeller 106 in the inflow.

As shown in FIG. 9, as an alternative to the rotating nose cap 110, a stationary nose cap 111 may be provided in the area of the nose Hub region of the impeller 106 may be provided. The nose cap 111 is held in position by a strut 109 fixed to the inlet passage 107. The nose cap 111 is also aerodynamically shaped so as not to disturb the inflow to the impeller 106 as possible. Further, the strut 109 is aerodynamically shaped to minimize the interference of the strut 109 to the inflow as small as possible. The strut 109 is disposed upstream of the adjustable vane 108, and the stationary nose dome 111 is formed longer than the rotating nose dome 110 in the axial direction of the shaft 104. Between the impeller 106 and the stationary nose hood 111, a relative movement takes place during operation of the turbocompressor 101. The nose cap 111 is spaced from the impeller 106 so that the impeller 106 does not contact the stationary nose cap 111 and thus can not grind and damage it.

The rotor dynamics of the turbocompressor rotor 103, i. The dynamic vibration behavior of the turbocompressor rotor 103 during operation of the turbocompressor 101 depends essentially on the geometry and structural design of the turbocompressor rotor 103 and the dynamic properties inherent in the bearing 105, in particular the rigidity and damping of the bearing 105. Conventionally, the bearing 105 is formed by a Kippsegmentgleitlager, which according to its design, construction and its operation has the appropriate stiffness and the corresponding damping. When starting the turbocompressor 103 on his

Operating speed of the turbocompressor 103 passes usually at least one critical speed. In order to avert damage to the turbocompressor rotor 103 when passing through the critical rotational speed, the radial oscillation amplitude of the turbocompressor rotor 103 must always be within design limits. These limits can be met if the rotor dynamics of the turbo compressor rotor 103 is set accordingly, in particular by the geometry and the structural design of the turbocompressor rotor 103 and the rigidity and the damping of the bearing 105.

Caused by the flying mounting of the impeller 106 are on the impeller 106 when passing through the critical speed often recorded high radial vibration amplitudes. As a result, the turbocompressor rotor 103 with its cantilevered rotor 106 is often difficult to control from a rotor-dynamic point of view.

It is also known that, especially at high gas densities, an interaction of the compressor rotor with the compressed gas can result in self-excited vibrations of the rotor, which can lead to the destruction of the machine. This phenomenon is counteracted by a rotor-dynamically favorable construction, whereby hitherto only the rotational speed and the mass distribution of the rotor as well as the damping and the rigidity of the bearing are to varying parameters.

The object of the invention is to provide a nose hood for a turbomachine rotor and a turbomachine with the turbomachine rotor having the nose hood, wherein the turbomachine has a balanced rotor dynamic behavior and thus is safe to operate.

The nose hood according to the invention for a turbomachine rotor, which has an impeller arranged to fly to a bearing point of the turbomachine rotor, can be connected axially to guide an axial supply and / or outflow of the impeller and has a coupling device with which the impeller and the nose hood are radially connected are mechanically coupled, so that the vibration behavior of the turbomachine rotor can be influenced. The turbomachine according to the invention has a turbomachine rotor, which has an impeller which is arranged to fly over the bearing point of the rotor, and the nose hood, wherein the impeller and the nose hood are radially coupled by means of the coupling device, so that the

Vibration behavior of the turbomachine rotor can be influenced.

This advantageously achieves that, in addition to the design of the bearing point and the geometric design of the turbomachinery rotor by means of the coupling device, the rotor dynamic behavior of the turbomachine rotor can be determined or influenced.

The nose hood engages with the coupling device on the

Impeller, which is cantilevered with respect to the bearing. Due to the flying bearing of the impeller is based on the bearing for the coupling device before a favorable lever arm for influencing the rotor dynamic behavior of the turbomachine rotor before. As a result, the rotor dynamic behavior of the turbomachine rotor can be influenced effectively and favorably by the nose hood.

Thus, the vibration of the turbomachine rotor is damped in operation by means of the coupling device, so that the maximum oscillation amplitude during operation of the turbomachine rotor is low. When operating the turbomachinery with high density gases, the amplitude of vibration of the turbomachine rotor may be so great that operation of the turbomachinery with these gases results in damage to the turbomachine. Due to the damping property of the coupling device, however, the oscillation amplitude of the turbomachine rotor is low, so that the turbomachine according to the invention can also be operated with these gases with high density and high reliability. As a result, the provision of the nose hood according to the invention in the turbomachine according to the invention implements new machine concepts possible, especially in high gas density applications such as carbon dioxide compressed to a high pressure.

The nose cap thus provides an additional

Design element, with which the damping of the vibration system can be favorably influenced.

It is preferable that the impeller has an externally accessible shaft bore having a cylindrical inner wall and the coupling means has a protrusion with a cylindrical outer wall insertable into the shaft bore forming a cylindrical annular gap between the outer wall of the protrusion and the inner wall of the shaft bore, and has a loading device, with which the annular gap for damping the vibration of the turbomachine rotor can be acted upon with pressurizing gas.

Characterized an annular, cylindrical gas cushion between the projection of the nose hood and the impeller is achieved with a flow of Beaufschlagungsgases through the annular gap. The gas cushion has a damping characteristic with which the vibration of the turbomachine rotor can be damped. By means of the loading device, the flow of the admission gas can be predetermined, so that the damping property of the gas cushion is adjustable. Between the impeller and the projection of the nose hood, the annular gap is provided, so that in spite of the damping coupling between the impeller and the nose hood, the impeller is not in contact with the nose hood. Therefore, the impeller and the nose hood are mechanically coupled without contact, so that mechanical wear in the coupling device on the impeller and the nose hood is prevented. It is preferable for the loading device to have a channel system formed in the nose hood for feeding the pressurizing gas into the annular gap, the pressurizing gas being able to flow into the annular gap through the outer wall of the protrusion.

Thus, the supply gas is guided to the annular gap in the interior of the nose hood, so that an additional space outside the nose hood need not be provided for the supply of the annular gap with the pressurizing gas. As a result, the loading device is designed to save space within the nose hood.

Furthermore, it is preferred that the coupling device has at least one labyrinth seal with labyrinth tips, which are attached to the outer wall of the projection and / or the inner wall of the impeller.

The apply gas flows through the labyrinth seal within the annular gap, i. around the labyrinth peaks, a multiplicity of vortices form at the labyrinth peaks, which increase the flow resistance of the admission gas in the annular gap. Thereby, the damping effect of the gas cushion, which is formed with the pressurizing gas within the annular gap, improved.

Preferably, the coupling device has a multiplicity of the labyrinth seals, between which in each case the admission gas for supplying the labyrinth seals can be fed into the annular gap.

The labyrinth seals can be individually designed individually so that an admission profile adapted to the rotor dynamics of the turbomachinery rotor can be generated within the annular gap. Thus, the individual labyrinth seals in the axial direction of the turbomachine rotor and in the radial direction may be formed differently, so that the individual seals have different damping and stiffness properties.

Alternatively, it is preferable that the coupling means comprise a honeycomb honeycomb seal, which are attached to the outer wall of the projection and / or the inner wall of the impeller.

Furthermore, it is preferred that the coupling device has a plurality of the honeycomb seals, between each of which the pressurizing gas for supplying the honeycomb seal can be fed into the annular gap.

Thus, the individual honeycomb seals can be designed differently, so that the individual honeycomb seals have different damping and stiffness properties.

It is preferred that the nose cap is fixed stationary relative to the impeller.

Thereby, the supply of the annular gap with the pressurizing gas within the nose hood is easy to accomplish, since between the nose cap and an external source of the admission gas, which is usually stationary, no relative movement takes place.

During operation of the turbomachine, the impeller rotates and the nose cap is stationary. As a result, a shear flow forms in the annular gap, which has a high damping.

Preferably, the turbomachine is a radial compressor, which preferably has an inlet channel for the impeller and at least one strut with which the nose hood is suspended in the inlet channel.

The strut is stationarily stably positioned relative to the impeller, whereby forces from the impeller via the Coupling device can be transferred to the nose cap on the strut to the inlet channel. Thereby, the engagement of the projection of the nose cap in the impeller is safe and accurate, so that the damping effect of the coupling device is effective.

Preferably, the strut is aerodynamically shaped.

As a result, the strut in the inlet channel has a low aerodynamic resistance, whereby the flow in the

Inlet of the strut is little disturbed. Thus, the turbomachine has a high efficiency.

It is further preferred that the strut is formed as a guide vane.

The fact that the strut is fixed in the inlet channel, it is stationary. Advantageously, the strut is the guide vane, so that by means of the strut, the inlet flow in the direction of the impeller can be correspondingly advantageously deflected. As a result, the inflow to the impeller is advantageously aerodynamically manipulatable.

It is preferred that the loading device can be supplied with the application gas through the strut.

As a result, the admission gas is guided from outside the inlet channel through the strut into the interior of the nose hood. Inside the nosecap is that

Channel system provided by the supply gas is guided to the outer wall of the projection, wherein from the outer wall of the projection of the impingement gas flows into the annular gap.

Preferably, the pressurizing gas is a process gas of the turbomachine. When the admission gas exits the annular gap, the admission gas mixes with the process gas of the turbomachine. Since the apply gas has the same composition as the process gas, contamination of the process gas by the process takes place

Beaufschlagungsgas not take place. Further advantageously, the apply gas may be tapped from the turbomachine and a separate source of the apply gas need not be provided.

Preferably, the turbomachine has at least one adjustable guide vane, which is arranged between the strut and the impeller.

By means of the guide vane can advantageously be positively manipulated the inflow to the impeller, so that the impeller has a high efficiency.

In the following, preferred embodiments of a turbocompressor according to the invention will be explained with reference to the attached schematic drawings. It shows:

Fig. 1 is a sectional view of the invention

Turbocompressor,

FIG. 2 detail X from FIG. 1, FIG.

3 detail Y of Fig. 2,

Fig. 4 shows a first embodiment of

Coupling device,

Fig. 5 shows a second embodiment of

Coupling device,

Fig. 6 shows a third embodiment of

Coupling device, 7 shows a fourth embodiment of the coupling device,

Fig. 8 shows a first example of a conventional turbocompressor and

9 shows a second example of a conventional turbocompressor.

As can be seen from FIGS. 1 to 3, a turbocompressor 1 has a housing 2 and a housing

Turbo compressor rotor 3, which is surrounded by the housing 2. The turbocompressor rotor 3 has a shaft 4, which is supported on a bearing 5 on the housing 2. Furthermore, the turbocompressor rotor 3 has an impeller 6, which is fastened to the shaft 4. The impeller 6 is arranged to be cantilevered relative to the bearing 5. The impeller 6 has a shaft bore 7, in which the shaft 4 engages, wherein the shaft 4, the shaft bore 7 does not completely penetrate. The shaft bore 7 is bounded by its inner wall 8, on which the shaft 4 rests firmly.

The turbocompressor 1 has an inlet channel 9, through which the inflow is guided to the impeller 6. The impeller 6 is a Radialverdichterrad with axial

Inflow characteristic, wherein the inlet channel 9 is arranged in the axial direction of the turbo compressor rotor 3.

In the inlet channel 9, a strut 10 is fixed to which a nose hood 11 is fixed, which is centered in the

Inlet channel 9 is arranged. The nose hood 11 has a projection 12 which engages in the shaft bore 7 from the inlet channel 9 ago. The projection 12 has an outer wall 13, which is located in the shaft bore 7. Due to the fact that the strut 10 holds the nose cap 11 centrally in the inlet channel 9, the outer wall 13 of the projection 12 is arranged concentrically with the inner wall 8 of the shaft bore 7. As a result, between the inner wall 8 of the Shaft bore 7 and the outer wall 13 of the projection 12, an annular gap 14 is formed.

In the annular gap 14, a labyrinth seal 15 is provided which has two axially successive labyrinths 16, 16 a. The labyrinths 16, 16 a are mounted on the outer wall 13 of the projection 12 and are arranged at a distance from the inner wall 8 of the shaft bore 7.

Within the nose cap 11, a channel system 17 is provided with which the annular gap 14 with a

Beaufschlagungsgas is provided. The channel system has a channel system entrance 18 into which the admission gas flows into the channel system 17 and a channel system exit 19, which is located on the outer wall 13 of the projection 12. The channel system outlet 19 is located inter alia between the two labyrinths 16, so that between the two labyrinths 16, the pressurizing gas flows into the annular gap 14.

The housing 2 has a feed nozzle 20 and a feed line 21, via which the admission gas is guided to the strut 10. The strut 10 is hollow and is connected with its cavity to the channel system inlet 18 on the nose hood 11 gas-conducting, so that of the

Feeding 20 via the feed line 21, the strut 10, the channel system inlet 18, the channel system 17 and the channel system outlet 19 between the labyrinths 16, 16a into the annular gap 14, the admission gas is guided.

The admission gas flowing through the channel system 17 splits into the stream (a) through the channel system exit 19 via the labyrinth 16 into the space immediately in front of the impeller 6 and into the stream (b) via the labyrinth 16a into the space between the projection 12 of FIG Shaft 4, from where it is also discharged through an end opening 19 a in the space immediately in front of the impeller 6. While the pressurizing gas flowing through the channel system outlets 19 flows along the labyrinths 16, 16a through the annular gap 14, it forms a gas cushion.

During operation of the turbocompressor 1 rotates the

Turbo compressor rotor 3. Due to the rotor dynamic behavior of the turbocompressor rotor 3, this experiences a bending vibration, which leads to a dynamic radial movement of the impeller 6. In contrast to the turbocompressor rotor 3, the nose hood 11 is held stable and stationary by means of the strut 10 in the inlet channel 9. As a result, in particular, a radial relative movement between the outer wall 13 of the projection 12 and the inner wall 18 of the shaft bore 7 forms, whereby the annular gap 14 changes its shape dynamically. Thereby, the thickness of the gas cushion, which is formed in the annular gap 14, changed, whereby the gas cushion supported on the nose cap 11 acts on the impeller damping. As a result, the dynamic radial movement of the impeller 6 is restricted so that the rotor-dynamic behavior of the turbocompressor rotor 3 is improved.

During operation of the turbocompressor 1, the turbocompressor rotor 3 and thus the impeller 6 rotate. Since the nasal hood 11 is stationary, a shear flow in the gas cushion is formed in the annular gap 14. As a result, the gas cushion has a high damping effect.

The turbocompressor 1 further comprises an adjustable stator 22, which is arranged in the axial direction of the turbo compressor rotor 3 between the impeller 6 and the strut 10. By means of the adjustable stator 22, the inflow can be manipulated to the impeller 6, in particular be subjected to a twist, so that the impeller 6 has a high thermodynamic efficiency.

In Fig. 4 is a first embodiment of

Coupling device shown schematically, wherein the labyrinth 16 applied to the projection 12 of the nose hood 11 is stored stationary. Arranged in the annular gap 14 opposite the labyrinth 16, the inner wall 8 of the shaft bore 6, which is moved relative to the labyrinth 16, is located.

In Fig. 5 is a second embodiment of

Coupling device shown schematically, wherein the labyrinth 16 is attached to the inner wall 8 of the shaft bore 7, so that the labyrinth 16 rotates relative to the outer wall 13 of the projection 12.

6, a third embodiment of the coupling device is shown, which is comparable to the first embodiment of FIG. 4, but with the difference that instead of the labyrinth 16 a honeycomb seal 23 is provided with a honeycomb 24.

The fourth embodiment of the coupling device shown in FIG. 7 is comparable to the second embodiment shown in FIG. 5, wherein, instead of the labyrinth 16, the honeycomb seal 23 with the honeycomb 24 is provided.

Claims

claims

1. nose hood for a turbomachine rotor (3), which has a to a bearing point (5) of the turbomachine rotor (3) on the fly impeller (6), wherein the nose hood (11) for guiding an axial inflow and / or outflow of the impeller ( 6) is axially connectable to this and has a coupling device with which the impeller (6) and the nose hood (11) are radially mechanically coupled, so that the vibration behavior of the turbomachine rotor (3) can be influenced.

2. nose cap according to claim 1, wherein the impeller (6) has an externally accessible shaft bore (7) with a cylindrical inner wall (8) and the coupling means a projection (12) having a cylindrical outer wall (13) in the shaft bore ( 7) to form a cylindrical annular gap (14) between the outer wall (13) of the projection (12) and the inner wall (8) of the shaft bore (7) is insertable, and having an urging means, with which the annular gap (14) for damping the Oscillation of the turbomachine rotor (3) can be acted upon with pressurizing gas.

A nasal hood according to claim 2, wherein the urging means comprises a channel system (17) formed in the nose cap (11) for supplying the pressurizing gas into the annular gap (14), the pressurizing gas gas being introduced into the nasal obturator

Annular gap (14) through the outer wall (13) of the projection (12) can be flowed.

A nasal hood according to claim 3, wherein the coupling means comprises at least one labyrinth seal (15) with labyrinth tips (16) attached to the outer wall (13) of the projection (12) and / or the inner wall (8) of the shaft bore (7) ,

5. Nose hood according to claim 4, wherein the coupling device has a plurality of the labyrinth seals (15), between which in each case the pressurizing gas for applying the labyrinth seals (15) into the annular gap (14) can be supplied.

6. Nose hood according to claim 3, wherein the coupling means comprises a honeycomb seal (23) with honeycomb (24) which in the outer wall (13) of the projection (12) and / or the inner wall (8) of the shaft bore (7) are mounted.

7. Nose hood according to claim 4, wherein the coupling device has a plurality of honeycomb seals (23), between which in each case the pressurizing gas for acting on the honeycomb seals (23) in the annular gap (14) can be fed.

8. Turbomachine with a turbomachine rotor (3) having a to a bearing point (5) of the turbomachine rotor (3) arranged in a flywheel (6), and a

Nose hood (11) according to one of claims 1 to 7, wherein the impeller (6) and the nose hood (11) are coupled radially by means of the coupling device, so that the vibration behavior of the turbomachine rotor (3) can be influenced.

9. turbomachine according to claim 8, wherein the nose hood (11) is fixed relative to the impeller (6) stationary.

10. Turbomachine according to claim 8 or 9, wherein the turbomachine is a centrifugal compressor (1).

11. Turbomachine according to claim 10, wherein the radial compressor (1) has an inlet channel (9) for the impeller (6) and at least one strut (10) with which the nose hood (11) in the inlet channel (1) is suspended.

12. Turbomachine according to claim 11, wherein the strut (10) is aerodynamically shaped.

13. Turbomachine according to claim 12, wherein the strut (10) is formed as a guide vane.

14. turbomachine according to any one of claims 11 to 13, wherein by the strut (10) therethrough the biasing means is supplied with the pressurizing gas.

15. Turbomachine according to one of claims 8 to 14, wherein the pressurizing gas is a process gas of the turbomachine.

A turbomachine according to any of claims 11 to 15, wherein the turbomachine has at least one adjustable vane (22) interposed between the strut (10) and the impeller (6)