CN117365675A - Self-adaptive structure for impeller rotor and stator gap - Google Patents
Self-adaptive structure for impeller rotor and stator gap Download PDFInfo
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- CN117365675A CN117365675A CN202210760102.8A CN202210760102A CN117365675A CN 117365675 A CN117365675 A CN 117365675A CN 202210760102 A CN202210760102 A CN 202210760102A CN 117365675 A CN117365675 A CN 117365675A
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- casing
- annular casing
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- annular
- tip
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- 238000009826 distribution Methods 0.000 claims abstract description 10
- 238000009423 ventilation Methods 0.000 claims abstract description 10
- 238000013016 damping Methods 0.000 claims description 9
- 230000003044 adaptive effect Effects 0.000 claims description 8
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 230000001105 regulatory effect Effects 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 238000013022 venting Methods 0.000 claims description 2
- 230000002093 peripheral effect Effects 0.000 claims 1
- 230000003068 static effect Effects 0.000 abstract description 4
- 238000000034 method Methods 0.000 description 4
- 230000001276 controlling effect Effects 0.000 description 3
- 230000007423 decrease Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000007790 scraping Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
- F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
- F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
- F01D11/14—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
- F01D11/16—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing by self-adjusting means
Abstract
The impeller rotor-stator clearance self-adaptive structure comprises a casing, rotor blades, blade tip clearances and a ventilation pipeline. The casing comprises an outer annular casing and an inner annular casing, and an annular chamber is defined between the outer annular casing and the inner annular casing; the blade tip gap is positioned between the blade tips of the rotor blades and the inner annular casing, and the ventilation pipeline is positioned on the outer annular casing and used for communicating the annular chamber with the atmosphere outside the casing so as to regulate the pressure of the annular chamber; the inner annular casing is arranged to be radially movable relative to the outer annular casing, and the rotor blades correspondingly drive the inner annular casing to automatically move by utilizing tip circumferential static pressure differences formed by circumferentially uneven distribution of tip gaps so that the tip gaps tend to be uniform. The impeller rotor-stator clearance self-adaptive structure can realize rotor-stator clearance self-adaptive adjustment, and can automatically ensure the concentric state of the rotor-stator.
Description
Technical Field
The invention relates to the field of impeller machinery, in particular to the field of rotor-stator gap control.
Background
Advanced gas turbines or other turbine-type rotating machinery have increasingly stringent rotor-stator clearances. Current active gap control techniques adjust the gap size by adjusting the stator ambient temperature and controlling the degree of thermal expansion. In order to ensure operational safety, it is generally required that the circumferential minimum clearance cannot be less than 0, i.e. no rub-off occurs.
However, due to the fact that the rotor and stator are inevitably eccentric in the assembly process, the eccentric value is usually 0.1-0.3 mm, and therefore gaps of 0.2-0.6 mm are usually formed in the maximum gap position, local position leakage is serious, and overall efficiency and working margin are affected.
The existing device for controlling the gap of the rotor and the stator or the auxiliary control part is used for detecting the gap size so as to adjust the gap of the rotor and the stator; or by controlling the force applied to the stator case to vary the size of the rotor-stator gap.
Disclosure of Invention
The invention aims to provide an impeller rotor-stator clearance self-adaptive structure which can automatically ensure the concentric state of a rotor-stator.
The impeller rotor-stator clearance self-adapting structure for achieving the purpose comprises a casing, rotor blades, blade tip clearances and a ventilation pipeline. The casing comprises an outer annular casing and an inner annular casing, and an annular chamber is defined between the outer annular casing and the outer annular casing; the blade tip gap is positioned between the blade tips of the rotor blades and the inner annular casing, and the ventilation pipeline is positioned on the outer annular casing and used for communicating the annular chamber with the atmosphere outside the casing so as to regulate the pressure of the annular chamber; the inner annular casing is arranged to be radially movable relative to the outer annular casing, so that the inner annular casing is driven to automatically move by utilizing the tip circumferential static pressure difference formed by the circumferential uneven distribution of the tip gaps corresponding to the rotor blades, and the tip gaps tend to be uniform.
In one or more embodiments, the structure further includes an elastic damping member circumferentially distributed within the annular cavity and connecting the outer annular casing and the inner annular casing.
In one or more embodiments, the elastic damping member includes an elastic support and a damper that connect the outer annular casing and the inner annular casing in parallel.
In one or more embodiments, the vent conduit includes a restriction for regulating the pressure of the annular chamber.
In one or more embodiments, a sealing ring is disposed between the outer annular casing and the inner annular casing.
In one or more embodiments, the inner circumferential surface of the inner annular casing is coated with an abradable coating.
The self-adaptive structure of the impeller rotor and stator gap does not need additional control, and can drive the inner annular casing to move only by virtue of the circumferential static pressure difference of the blade tip caused by uneven blade tip gap until the blade tip gap tends to be uniform. At the moment, the external force caused by the air pressure difference disappears, so that the concentricity between the rotor and the casing is automatically adjusted, and the uniform circumferential gap distribution and the optimal state are ensured.
Drawings
The above and other features, properties and advantages of the present invention will become more apparent from the following description in conjunction with the accompanying drawings and embodiments, in which:
FIG. 1 is a schematic view of the main structure of a rotor of a gas turbine;
FIG. 2 is a schematic illustration of a typical engine rotor-stator clearance feature;
FIG. 3 is a schematic cross-sectional view of one embodiment of an impeller rotor-stator gap adaptation structure;
FIG. 4 is a schematic view of the rotor in an eccentric state;
fig. 5 is a schematic diagram of the rotor in an adaptive state.
Detailed Description
The present invention will be further described with reference to specific embodiments and drawings, in which more details are set forth in the following description in order to provide a thorough understanding of the present invention, but it will be apparent that the present invention can be embodied in many other forms than described herein, and that those skilled in the art may make similar generalizations and deductions depending on the actual application without departing from the spirit of the present invention, and therefore should not be construed to limit the scope of the present invention in terms of the content of this specific embodiment.
It is noted that these and other figures are merely examples, which are not drawn to scale and should not be construed as limiting the scope of the invention as it is actually claimed.
Referring to fig. 1, the rotor-stator structure of the gas turbine mainly includes a rotor blade 3, a stator blade 81, a hub 53, a casing 51, and the like, and the rotor blade 3 and the casing 51 form a tip clearance 52.
Fig. 2 shows a schematic representation of a typical engine rotor-stator clearance characteristic, which includes a typical annular stator case 40 and rotor blades 3. When the engine is designed to work, a tip clearance 52 exists between the rotor blade 3 rotating at a high speed and the annular stator case 40. In order to pursue higher efficiency and operating margins, the tip clearance 52 between the rotor blade 3 and the casing 51 is required to be as small as possible, and in order to ensure operational safety, it is generally required that the circumferential minimum clearance cannot be less than 0, i.e. no snagging occurs; too large a gap also results in airflow leakage, which in turn reduces engine efficiency and operating margin.
Because the rotor and stator are inevitably eccentric in the assembly process and the operation process, the gap distribution is uneven, and the requirements in actual work cannot be met.
In order to realize the automatic adjustment of concentricity between the rotor and the casing, the self-adaptive structure of the impeller rotor and stator gap can automatically adjust the circumferential gap so as to ensure that the rotor and stator gap is in an optimal state, and the circumferential gap is uniformly distributed and is in an optimal state.
Referring to fig. 3, the impeller-rotor-stator clearance adaptive structure described above includes a casing 51, rotor blades 3, and tip clearances 52. The rotor blades 3 are circumferentially arranged on the disk, and the casing 51 comprises an outer annular casing 35 and an inner annular casing 20, between which an annular chamber 9 is defined. A tip clearance 52 is located between the tip of the rotor blade 3 and the inner annular casing 20.
The structure further comprises a vent pipe 5, wherein the vent pipe 5 is positioned on the outer annular casing 35 and is used for communicating the annular chamber 9 with the casing outer flow passage so as to regulate the pressure of the annular chamber 9. The inner annular casing 20 is disposed to be radially movable relative to the outer annular casing 35, so as to drive the inner annular casing 20 to automatically move by using a circumferential differential pressure formed by a circumferentially uneven distribution of tip clearances 52 corresponding to each rotor blade 3, so that each tip clearance tends to be uniform.
The radial direction described below refers to the radial direction with respect to the casing 51, and may be understood as the up-down direction in fig. 3; the axial direction can be understood as the left-right direction in fig. 3; the circumferential direction refers to the direction around the casing 51, and can be understood as the direction perpendicular to the paper surface of fig. 3.
With continued reference to FIG. 3, the rotor blades 3 are circumferentially disposed on the disk with a tip clearance 52 formed between the tips of the rotor blades 3 and the inner annular casing 20.
In one embodiment, to prevent rubbing between the rotor blades 3 and the inner annular casing 20, an easily-abradable coating 2 is sprayed on the inner circumferential surface of the inner annular casing 20 to ensure safe operation of the engine without dangerous scraping. At this time, the tip clearance 52 is formed between the abradable coating 2 and the tips of the rotor blades 3, and the annular plurality of tip clearances 52 communicate with each other to form the airflow space 10, as shown in fig. 4.
In fig. 4, the airflow space 10 is a cavity formed by mutually communicating a plurality of tip clearances 52 between the tips of the rotor blades 3 and the inner annular casing 20, and the annular chamber 9 is a cavity formed by the inner annular casing 20 and the outer annular casing 35.
Referring to fig. 3, in one embodiment, a seal ring 8 is further disposed between the outer annular casing 35 and the inner annular casing 20, and by providing a seal ring 8 structure in each of the axial front-rear directions of the outer annular casing 35 and the inner annular casing 20, effective sealing between the outer annular casing 35 and the inner annular casing 20 can be achieved.
The impeller rotor-stator clearance self-adapting structure further comprises a vent pipe 5 positioned on the outer annular casing 35, wherein the vent pipe 5 is used for communicating the annular chamber 9 with the casing outer runner so as to regulate the pressure of the annular chamber 9. The annular chamber 9 is thus not a sealed space, but communicates with the casing outer flow channel through the venting duct 5.
Since the annular chamber 9 is defined by the inner annular casing 20 and the outer annular casing 35, and the inner annular casing 20 is arranged so as to be radially movable with respect to the outer annular casing 35, when the volume of the annular chamber 9 changes, the pressure in the annular chamber 9 does not change greatly due to the action of the ventilation duct 5, and remains consistent with the casing outer flow passage all the time.
On the basis of the above-described embodiment, the ventilation duct 5 also comprises throttling means for regulating the pressure of the annular chamber 9. For example, a movable perforated plate or the like located inside the ventilation duct 5, which can regulate the flow of ventilation air into or out of the annular chamber 9, and thus regulate the pressure of the annular chamber 9.
In one embodiment, the structure further comprises elastic damping members 30, wherein the elastic damping members 30 are circumferentially distributed in the annular chamber 9 and connect the outer annular casing 35 and the inner annular casing 20, so as to realize a radially movable connection between the outer annular casing 35 and the inner annular casing 20.
Preferably, the elastic damping member 30 includes an elastic support 6 and a damper 7 that connect the outer annular casing 35 and the inner annular casing 20 in parallel. The elastic support 6 and the damper 7 in the elastic damping piece 30 act together, so that instability of the elastic adjusting mechanism under the working vibration of the engine can be avoided, the damper 7 can filter high-frequency vibration excitation of the engine, and unexpected collision and grinding results caused by the vibration instability of the inner annular casing 20 are prevented.
The working principle of the self-adaptive structure of the rotor-stator clearance of the impeller is that the circumferential pressure difference of the blade tip formed by the blade tip clearances 52 is utilized, and the circumferential pressure difference formed by the circumferential uneven distribution of the blade tip clearances 52 corresponding to the rotor blades is utilized to drive the inner annular casing 20 to automatically move so as to lead the blade tip clearances 52 to be uniform.
Specifically, since the rotor and the stator center are generally not identical when the engine is in operation, and the rotor has a certain eccentricity compared with the casing, the tip clearances 52 corresponding to the rotor blades 3 are unevenly distributed in the circumferential direction, and reference is made to the first position 10B and the second position 10A shown in fig. 4.
The tip clearances 52 are circumferentially non-uniform, i.e., result in a circumferentially non-uniform circumferential spatial distribution of the annular airflow space 10 formed by the circumferentially distributed tip clearances 52.
As shown in fig. 4, in the airflow space 10, the first position 10B represents a space-smaller area of the tip clearance 52 where the circumferential gas leakage between adjacent rotor blades 3 is small, and thus the local gas pressure at the first position 10B is relatively high; while at the second position 10A where the space of the tip clearance 52 is larger, the circumferential gas leakage between adjacent rotor blades 3 is more, resulting in a partial gas pressure at the second position 10B being lower than at 10B.
Thus, each tip clearance 52 circumferentially creates a tip circumferential pressure differential. Meanwhile, since the annular chamber 9 defined by the outer annular casing 35 and the inner annular casing 20 is always communicated with the casing outer flow passage through the air passage 5, the air pressure of the annular chamber 9 circumferentially coincides.
Since the impeller rotor-stator structure is a pressurizing member, the air pressure in the annular air flow space 10 is pressurized; the annular chamber 9 is communicated with the outer flow passage of the casing through the ventilation pipeline 5, and the pressure of the annular chamber 9 is not pressurized. The pressure in the annular chamber 9 is thus less than the pressure in the annular gas flow space 10 inside the pressure increasing member. If the constant pressure in the annular chamber 9 is X, the pressure at the first location 10B is Y and the pressure at the second location 10A is Z. Since Y > Z, |Y-X| > Z-X|. Therefore, at the first position 10B where the tip clearance 52 is small, the differential pressure between the inside and outside of the casing, that is, the differential pressure between the annular chamber 9 and the annular airflow space 10 is greater than the differential pressure between the inside and outside at the second position 10A where the tip clearance 52 is large, an unbalanced differential pressure occurs between the annular chamber 9 and the annular airflow space 10.
The inner ring casing 20 moves to the first position 10B side under the driving of the unbalanced pressure difference until the tip clearances 52 tend to be uniform, and the external force caused by the air pressure difference disappears.
Specifically, referring to FIG. 3, the tip clearance 52 at the first location 10B is smaller and the tip clearance 52 at the second location 10B is larger. The pressure difference created between the tip clearance 52 and the annular chamber 9 at the first location 10B will be greater than the pressure difference between the tip clearance 52 and the annular chamber 9 at the second location 10A compared to the tip clearance 52 at the second location 10A. The difference in pressure difference will cause the inner annular casing 20 to move radially to increase the volume of the tip clearance 52 at the first location 10B and decrease the pressure value of the tip clearance 52 at the first location 10B, thereby eliminating the maldistribution of the annular airflow space 10 and causing the tip clearance 52 to tend to be uniform.
At this point, the radially outward movement of the inner annular casing 20 at the first position 10B will compress the annular chamber 9, at which point the increased pressure of the annular chamber 9 will be released through the breather conduit 5, while the tip clearance 52 space at the first position 10B increases, thereby reducing the local pressure thereat. While at the second position 10A, the radially inward movement of the inner annular casing 20 increases the volume of the annular chamber 9 thereat and decreases the space of the tip clearance 52 at the second position 10A to increase the local pressure of the tip clearance 52 at the second position 10A and decrease the local pressure at the first position 10B, thereby maintaining the tip clearances 52 circumferentially uniform and eventually forming a circumferentially uniform distribution of the tip clearances as shown in fig. 5.
The operation of the impeller-rotor-stator gap adaptive structure will be described below.
Due to machining, assembly errors and the like, when the engine works, the centers of the rotor and the stator are generally inconsistent, the rotor has a certain eccentric condition compared with the casing, and the eccentric condition leads to uneven distribution of the blade tip gaps 52 between the rotor blades 3 and the inner annular casing 20 along the circumferential direction.
The local air pressure at the position with small blade tip clearance is high, and the local air pressure at the position with large clearance is low. Meanwhile, the air pressure of the annular chamber 9 formed by the inner annular casing 20 and the outer annular casing 35 is kept consistent in the circumferential direction, so that the pressure in the annular chamber 9 is a stable value.
At the position with small blade tip clearance, the pressure difference formed by the annular cavity 9 is larger than the pressure difference formed at the position with large blade tip clearance, so that the inner annular casing 20 can be pushed by the unbalanced pressure difference and move from the side with small clearance to the side with large clearance until the blade tip clearance tends to be uniform, and the external force caused by the air pressure difference disappears, so that the uniform clearance state is achieved.
The self-adaptive structure of the impeller rotor and stator gap does not need additional control, and can drive the inner annular casing to move only by virtue of the circumferential static pressure difference of the blade tip caused by uneven blade tip gap until the blade tip gap tends to be uniform, so that the self-adaptive structure is simple in structure and unnecessary parts are not required to be arranged. By means of self-adaptive movement of the inner annular casing, external force caused by air pressure difference disappears, so that concentricity between the rotor and the casing is automatically adjusted, circumferential gap distribution is guaranteed to be uniform and in an optimal state, local position leakage caused by rotor and stator eccentricity is avoided, and overall efficiency and margin are guaranteed.
This application uses specific words to describe embodiments of the application. Reference to "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic is associated with at least one embodiment of the present application. Thus, it should be emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various positions in this specification are not necessarily referring to the same embodiment. Furthermore, certain features, structures, or characteristics of one or more embodiments of the present application may be combined as suitable.
While the invention has been described in terms of preferred embodiments, it is not intended to be limiting, but rather to the invention, as will occur to those skilled in the art, without departing from the spirit and scope of the invention. Therefore, any modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention fall within the protection scope defined by the claims of the present invention.
Claims (6)
1. Impeller rotor clearance self-adaptation structure includes:
the casing (51) comprises an outer-layer annular casing (35) and an inner-layer annular casing (20), and an annular chamber (9) is defined between the outer-layer annular casing (35) and the inner-layer annular casing (20);
rotor blades (3) circumferentially arranged on the disk;
a tip clearance (52) between the tip of the rotor blade (3) and the inner annular casing (20);
the structure is characterized in that the structure also comprises:
the ventilation pipeline (5) is positioned on the outer annular casing (35) and is used for communicating the annular chamber (9) with an outer casing runner so as to regulate the pressure of the annular chamber (9);
the inner annular casing (20) is arranged to be radially movable relative to the outer annular casing (35) so as to drive the inner annular casing (10) to automatically move by utilizing a circumferential pressure difference formed by non-uniform circumferential distribution of tip clearances (52) corresponding to the rotor blades (3) so as to enable the tip clearances to be uniform.
2. The impeller-rotor gap adaptive structure of claim 1, wherein,
the structure further comprises elastic damping pieces (30), wherein the elastic damping pieces (30) are circumferentially distributed in the annular cavity (9) and are connected with the outer annular casing (35) and the inner annular casing (20).
3. The impeller-rotor gap adaptive structure according to claim 2, characterized in that,
the elastic damping piece (30) comprises an elastic support (6) and a damper (7) which are connected with the outer annular casing (35) and the inner annular casing (20) in parallel.
4. The impeller-rotor gap adaptive structure of claim 1, wherein,
the venting duct (5) comprises throttling means for regulating the pressure of the annular chamber (9).
5. The impeller-rotor gap adaptive structure of claim 1, wherein,
and a sealing ring (8) is arranged between the outer-layer annular casing (35) and the inner-layer annular casing (20).
6. The impeller-rotor gap adaptive structure of claim 1, wherein,
and an easily-ground coating (2) is sprayed on the inner peripheral surface of the inner annular casing (20).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210760102.8A CN117365675A (en) | 2022-06-30 | 2022-06-30 | Self-adaptive structure for impeller rotor and stator gap |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210760102.8A CN117365675A (en) | 2022-06-30 | 2022-06-30 | Self-adaptive structure for impeller rotor and stator gap |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117365675A true CN117365675A (en) | 2024-01-09 |
Family
ID=89391523
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210760102.8A Pending CN117365675A (en) | 2022-06-30 | 2022-06-30 | Self-adaptive structure for impeller rotor and stator gap |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117365675A (en) |
-
2022
- 2022-06-30 CN CN202210760102.8A patent/CN117365675A/en active Pending
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