Blade tip clearance sensor mounting structure and turbine outer ring fixing structure

Abstract

The blade tip clearance sensor mounting structure used for fixing the blade tip clearance sensor comprises a mounting seat, an air inlet hole and a conical guide groove, and the mounting seat is arranged in a cavity on the radial outer side of an outer ring and used for fixing the blade tip clearance sensor; the air inlet hole is formed in a seat body of the mounting seat; the conical guide groove is annularly formed along the mounting base, an inlet communicates with the air inlet, an outlet communicates with the blade tip gap, and the conical guide groove is used for guiding airflow to flow so as to form a cold air film layer in the blade tip gap area. The blade tip clearance sensor mounting structure can realize the mounting and protection of the blade tip clearance sensor so as to obtain more accurate measurement. The invention further provides a turbine outer ring fixing structure.

Description

Technical Field

[0001] The invention relates to the field of testing, in particular to the field of testing blade tip clearance. Background Art

[0002] During engine operation, in order to obtain turbine efficiency data, monitor the clearance to ensure test safety, and verify the ACC tip clearance adjustment capability, a tip clearance sensor is often designed at the tip position to measure the tip clearance of the engine in working condition.

[0003] The blade tip sensor is usually fixed on the outer ring of the turbine. Lead holes are designed on the middle casing and the turbine casing to lead the test lead out of the engine. Generally speaking, the blade tips of the first and second stage moving blades and the outer ring of the turbine are directly in a high-temperature and high-pressure gas environment. The sensor will directly contact the high-temperature gas, which places high requirements on the temperature resistance of the sensor. At present, capacitive sensors or ray sensors are widely used for non-contact blade tip clearance measurement.

[0004] Although capacitive sensors or ray sensors have high reliability, the stability and accuracy of sensor measurement data are greatly affected by the medium, and the sensor is also easily damaged when working at high temperatures for a long time. According to the actual field measurement results of capacitive sensors, when the engine is running at high conditions, sensor failure often occurs or data fluctuations are too large, making the data without reference value, which directly leads to the inability to conduct effective safety monitoring and accurate data analysis. Through research, it is found that this phenomenon is caused by the contamination of the sensor by the excess of incomplete combustion or the drastic change of the medium parameters, that is, the abnormal change of the dielectric constant ∈ of the medium causes the capacitance C to be unstable, C = ∈0∈S / d, where d is the tip clearance, S is the area of ​​the capacitor plate, and ∈0 is the vacuum dielectric constant. Summary of the invention

[0005] An object of the present invention is to provide a blade tip clearance sensor mounting structure to achieve accurate measurement of blade tip clearance.

[0006] To achieve the above-mentioned purpose, a blade tip clearance sensor mounting structure is provided, which is used to fix the blade tip clearance sensor, and the blade tip clearance sensor is used to measure the clearance between the moving blade and the outer ring. The structure includes a mounting seat, an air inlet hole and a conical guide groove. The mounting seat is arranged in a cavity radially outside the outer ring, and is used to fix the blade tip clearance sensor; the air inlet hole is arranged on the seat body of the mounting seat; the conical guide groove is arranged on the mounting seat, the inlet is connected to the air inlet hole, and the outlet is connected to the blade tip clearance, and is used to guide the airflow to form a cold air film layer in the blade tip clearance area.

[0007] In one or more embodiments, a guide tail end of the tapered guide groove is inclined toward an axis of the mounting seat.

[0008] In one or more embodiments, the structure further includes air film holes arranged through the outer ring.

[0009] In one or more embodiments, the axis of the air film hole is radial and / or forms an angle with the radial direction.

[0010] In one or more embodiments, the mounting seat further includes a position-limiting anti-rotation slot, and the tip clearance sensor includes a position-limiting boss for cooperating with the position-limiting anti-rotation slot.

[0011] In one or more embodiments, the outer ring is a turbine outer ring, and the turbine outer ring is fixed on the casing.

[0012] In one or more embodiments, the outer ring is on the compressor casing.

[0013] Another object of the present invention is to provide a turbine outer ring fixing structure, comprising a turbine outer ring and an intermediate casing, wherein the turbine outer ring includes the above-mentioned tip clearance sensor mounting structure, and also includes a positioning slot arranged on the axial side, and the intermediate casing includes a retaining ring and a limit pin, wherein the retaining ring is used to fix the turbine outer ring, and the limit pin is used to cooperate with the positioning slot to circumferentially fix the turbine outer ring.

[0014] In one or more embodiments, it also includes a turbine casing located radially outside the intermediate casing, the turbine casing includes a groove and a first lead hole located radially inside, the groove is used to fix the middle casing, the intermediate casing includes a second lead hole, the first lead hole and the second lead hole are used to lead out test leads connected to a tip clearance sensor.

[0015] The above-mentioned tip clearance sensor mounting structure can realize the installation of the tip clearance sensor without affecting the assembly of the outer ring; the cooling air holes and the tapered guide grooves on the designed mounting seat together form a spatial cooling air surround, which reduces the operating temperature of the sensor, and the tapered guide groove forms an isolating cooling air film in the tip clearance of the engine flow channel, ensuring that the sensor measurement medium is relatively stable, improving the stability of the clearance measurement, and avoiding high-temperature combustion gas contamination of the sensor when the engine is in a high state, thereby improving the accuracy of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0017] Figure 1 It is a cross-sectional view of the turbine outer ring and turbine blades;

[0018] Figure 2 It is a three-dimensional schematic diagram of the turbine outer ring;

[0019] Figure 3is a radial cross-sectional view of the tip clearance sensor mounting structure;

[0020] Figure 4 is a circumferential cross-sectional view of the tip clearance sensor mounting structure;

[0021] Figure 5 It is a schematic diagram of the streamlines of the cooling air in the outer ring of the turbine;

[0022] Figure 6 It is a top view of the streamlines in the blade tip area;

[0023] Figure 7 It is a left view of the streamlines in the blade tip area.

[0024] Symbols and Markings

[0025] 5 Moving blades

[0026] 6 Outer Ring

[0027] 10 Tip clearance sensor

[0028] 11 Test leads

[0029] 15 Limiting boss

[0030] 21 Mounting seat

[0031] 22 Air Inlet

[0032] 23 Conical guide groove

[0033] 24 Air film hole

[0034] 25 Limit anti-rotation slot

[0035] 60 Turbine outer ring

[0036] 63 Positioning slot

[0037] 64 Chamber

[0038] 68 Axial limit rib

[0039] 69 Radial mating surface

[0040] 70 Intermediate Casing

[0041] 72 Snap ring

[0042] 75 Second lead hole

[0043] 80 Turbine Case

[0044] 81 Grooves

[0045] 85 First lead hole

[0046] 201 High temperature gas

[0047] 202 Cooling air

[0048] 210 Mounting cavity DETAILED DESCRIPTION

[0049] The present invention is further described below in conjunction with specific embodiments and drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the protection scope of the present invention should not be limited by the content of this specific embodiment.

[0050] It should be noted that these and other subsequent drawings are only examples and are not drawn to scale, and should not be used to limit the actual scope of protection required by the present invention.

[0051] The blade tip clearance sensor is used to measure the clearance between the moving blade 5 and the outer ring 6. The existing blade tip clearance sensor is exposed to high-temperature combustion gas for a long time and is easily affected by the violent fluctuation of the medium in the engine flow channel, resulting in the inaccurate measurement accuracy of the sensor. Therefore, it is necessary to realize the installation of the blade tip clearance sensor on the engine without affecting other functions of the engine, reduce the working environment temperature of the sensor, and increase the service life; and it can reduce the influence of the violent fluctuation of the medium in the engine flow channel on the measurement accuracy of the sensor, and prevent the combustion surplus from contaminating the sensor.

[0052] Reference Figures 1 to 3 As shown, the blade tip clearance sensor mounting structure is used to fix the blade tip clearance sensor 10 , and includes a mounting seat 21 , an air inlet hole 22 and a tapered guide groove 23 .

[0053] The mounting seat 21 is arranged in the cavity 64 radially outside the outer ring 6 for fixing the blade tip clearance sensor 10 without affecting the normal installation and use of the outer ring. Figure 3 In the embodiment shown, the mounting seat 21 is located between the concave cavity outside the casting surface of the turbine outer ring 60 and the concave cavity inside the middle casing. In addition, the tip clearance sensor mounting structure can also be arranged on the compressor casing, in which case the compressor casing is the outer ring of the mounting seat.

[0054] The mounting seat 21 provides a mounting cavity 210, and the blade tip clearance sensor 10 is fixed to the mounting seat 21 by means including but not limited to welding. The mounting cavity 210 of the mounting seat 21 is provided with a double cylindrical step hole in the radial direction of the outer ring, such as Figure 2 As shown, the step surface of the double cylindrical step hole fits tightly with the bottom surface of the blade tip clearance sensor 10 to ensure sealing.

[0055] In some embodiments, the mounting seat 21 further includes a limit anti-rotation slot 25, and the tip clearance sensor 10 includes a limit boss 15 for cooperating with the limit anti-rotation slot. Figure 2 and Figure 4 Understand that the sensor is prevented from rotating circumferentially along the center line.

[0056] In order to reduce the influence of high-temperature gas on the measurement accuracy of the sensor, an air inlet 22 and a conical guide groove 23 are designed inside the outer ring to introduce cold air E, forming a cold air flow path inside the outer ring, so that a conical isolation air film is formed between the sensor and the high-temperature gas, and the air film protection of the sensor is realized. Specifically, the air inlet 22 is arranged on the seat body of the mounting seat 21, and is arranged on the mounting seat 21 along the seat body, and is used to introduce the cooling air flow E at the outer ring. This structure directly uses the high-pressure cold air of the outer ring, and does not need to provide an additional cold air source to provide cooling for the sensor.

[0057] The conical guide groove 23 is arranged circumferentially along the mounting seat 21, and is opened from the inner cylindrical surface of the connection between the outer ring 6 and the mounting seat 21 to the radial side of the outer ring base, the inlet is connected to the air inlet hole 22, and the outlet is connected to the blade tip gap 7, and is used to guide the airflow to form a cold air film layer in the area of ​​the blade tip gap 7. That is, the cold air flowing out of the multiple circular air inlet holes 22 is guided by the conical guide groove 23 and then remixed together, and flows into the blade tip gap of the engine flow channel at a certain angle, forming a conical isolation air film in the flow channel.

[0058] Preferably, the guiding tail end of the tapered guiding groove 23, i.e. Figure 1 The lower end of the blade is inclined toward the axial direction of the mounting seat 21, guiding the cooling airflow to form a stream of cold air at the bottom side of the mounting seat and forming a relatively uniform conical isolation air film in the blade tip area.

[0059] The tip gap 7 is located in the engine flow channel. Therefore, by forming a cold air film layer in the tip gap 7 area, the sensor can be surrounded by cold air in space together with the air inlet 22, which can effectively block the heat from the outer ring from being transferred to the sensor, thereby reducing the operating temperature of the sensor. At the same time, a cold air film layer is formed in the engine flow channel as an isolation air film to ensure that the sensor measurement medium is relatively stable, improve the stability of the gap measurement, and avoid high-temperature fuel gas contamination of the sensor when the engine is in a high state.

[0060] The sensor probe mounted on the outer ring and the rotor blade tip form a variable capacitor, and the capacitance of the variable capacitor changes as the gap between the probe and the rotor blade tip changes. After the sensor is calibrated before assembly, the blade tip clearance can be calculated based on the change in capacitance during the test.

[0061] Figure 5The schematic diagram of the cold air flow line E of the isolated air film when the blade 5 turns to the sensor position in the simulation results is given. The specific streamline diagram of the high-temperature gas and the cold air at the relative position of the blade 5 and the tip clearance sensor is shown in Figure 6 and Figure 7 , where the high-temperature combustion gas 201 is a black line and the cooling gas 202 is a gray line. It can be seen that the cooling gas forms a relatively uniform conical isolation gas film in the blade tip area, and only a small amount of combustion gas passes through the isolation gas film. The cooling gas 202 significantly mixes the high-temperature combustion gas 201, so that the sensor is effectively protected.

[0062] Preferably, the structure further includes an air film hole 24 provided through the outer ring 6, such as Figures 1 to 3 The axis of the air film hole 24 is either radial or forms an angle with the radial direction, so as to guide the cooling airflow at the outer ring to the blade tip clearance.

[0063] In the structural design, the angle and height of the conical guide groove and the number of air film holes on the test seat should be reasonably selected according to the hot clearance of the engine design to ensure that when the blade tip surface and the sensor measurement surface are opposite, the conical isolation air film wraps the cylindrical space corresponding to the sensor measurement surface to the greatest extent. The more adequate the air film protection, the higher the measurement accuracy. The spacing between adjacent air inlet holes 22 on the test seat should be as small as possible, otherwise the conical guide groove will not guide sufficiently and the isolation air film cannot be effectively formed.

[0064] The above structure is easy to implement and has no effect on the assembly of the outer ring. The installation of the tip clearance sensor on the engine is achieved without affecting other functions of the engine. The air holes are distributed in an annular shape inside the cylindrical tip clearance sensor mounting seat, and together with the conical guide groove, the sensor is surrounded by cold air in space, which can effectively block the heat of the outer ring substrate from being transferred to the sensor, reduce the working environment temperature of the sensor, and increase its service life. It can also reduce the impact of violent fluctuations of the medium in the engine flow channel on the measurement accuracy of the sensor, and prevent the sensor from being contaminated by combustion waste.

[0065] In combination with the introduction of the above-mentioned blade tip clearance sensor installation structure, a turbine outer ring fixing structure can also be understood, and the turbine outer ring fixing structure includes a turbine outer ring 60, an intermediate casing 70, and a turbine casing 80 that are sequentially distributed outward in the radial direction. The turbine outer ring 60 includes the above-mentioned blade tip clearance sensor installation structure, and also includes a positioning groove 63 arranged on the axial side. The intermediate casing 70 includes a retaining ring 72 and a limiting pin (not shown in the figure). The retaining ring 72 is used to fix the turbine outer ring 60, and the limiting pin is used to cooperate with the positioning groove 63 to fix the turbine outer ring 60 in the circumferential direction.

[0066] The rough material of the turbine outer ring is preferably processed by precision casting. The outer contour of the mounting seat, the tapered guide groove and the outer cavity features of the turbine outer ring are all guaranteed during casting. The circular hole on the test seat and the substrate cooling air film hole are formed by electromachining.

[0067] Combination Figure 1 and Figure 3 As shown, the turbine outer ring 60 also includes a radial mating surface 69 and an axial limiting rib plate 68. The radial mating surface 69 is used to contact with the intermediate casing 70 to achieve radial positioning, and the axial limiting rib plate 68 is also used to cooperate with the intermediate casing 70 to achieve axial positioning.

[0068] The turbine casing 80 includes a groove 81 and a first lead hole 85 located on the radial inner side. The groove is used to fix the middle casing 70. The intermediate casing includes a second lead hole 75. The first lead hole 85 and the second lead hole 75 are used to lead out the test lead 11 connected to the blade tip clearance sensor, and then lead out of the turbine casing.

[0069] It should be noted that the use of terms such as "first" and "second" to limit components is only to facilitate the distinction between corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0070] In the description of the present application, it is necessary to understand that the orientation or positional relationship indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise stated, these directional words do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contour of each component itself. The directional words "axial" and "radial" refer to the direction relative to the engine, the axial direction is the axial direction of the engine shaft, and the radial direction is the radius direction of the engine wheel.

[0071] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0072] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A blade tip clearance sensor mounting structure, used to fix a blade tip clearance sensor, wherein the blade tip clearance sensor is used to measure the clearance between a moving blade and an outer ring, and is characterized in that: include: A mounting seat, disposed in the cavity radially outside the outer ring, for fixing the blade tip clearance sensor; An air inlet hole is arranged on the seat body of the mounting seat; as well as A conical guide groove is arranged on the mounting seat, an inlet of which is connected to the air inlet hole, and an outlet of which is connected to the blade tip gap, and is used to guide the airflow to form a cold air film layer in the blade tip gap area.

2. The tip clearance sensor mounting structure according to claim 1, characterized in that: The guide tail end of the tapered guide groove is inclined toward the axis of the mounting seat.

3. The tip clearance sensor mounting structure according to claim 1, characterized in that: The structure also includes air film holes arranged through the outer ring.

4. The tip clearance sensor mounting structure according to claim 3, characterized in that: The axis of the air film hole is radial and / or forms an angle with the radial direction.

5. The tip clearance sensor mounting structure according to claim 1, characterized in that: The mounting seat also includes a position-limiting anti-rotation slot, and the tip clearance sensor includes a position-limiting boss for cooperating with the position-limiting anti-rotation slot.

6. The tip clearance sensor mounting structure according to claim 1, characterized in that: The outer ring is a turbine outer ring, and the turbine outer ring is fixed on the casing.

7. The tip clearance sensor mounting structure according to claim 1, characterized in that: The outer ring is on the compressor casing.

8. A turbine outer ring fixing structure, comprising a turbine outer ring and an intermediate casing, characterized in that: The turbine outer ring includes the tip clearance sensor mounting structure as described in claims 1-6, and also includes a positioning slot arranged on the axial side. The intermediate casing includes a retaining ring and a limit pin. The retaining ring is used to fix the turbine outer ring, and the limit pin is used to cooperate with the positioning slot to circumferentially fix the turbine outer ring.

9. The turbine outer ring fixing structure according to claim 8, characterized in that: It also includes a turbine casing located radially outside the intermediate casing, the turbine casing including a groove and a first lead hole located radially inside, the groove is used to fix the middle casing, the intermediate casing includes a second lead hole, the first lead hole and the second lead hole are used to lead out test leads connected to a tip clearance sensor.

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