A sealing gap real-time control system based on high-temperature shape memory alloy driving

Abstract

The application provides a sealing gap real-time control system based on high-temperature shape memory alloy driving, which comprises a stator casing, a rotor, a sealing ring assembly and an active gap control unit; the active gap control unit is installed between the stator casing and the sealing ring assembly, the gap between the sealing ring assembly and the rotor is adjusted by controlling the radial displacement of the sealing ring assembly; the stator casing is internally provided with an annular cooling channel, the central axis of the annular cooling channel and the central axis of the stator casing are coaxially arranged, and cooling airflow from a compressor is flowed in the annular cooling channel; the application amplifies the displacement generated by the driver through a lever sliding block mechanism, reduces the length of the high-temperature shape memory alloy and reduces the cooling airflow volume; the sealing ring adopts an "integral ring block + connecting block step tooth" structure, which can realize radial movement and avoid the generation of axial gaps to reduce the leakage.

Description

Technical Field

[0001] This invention relates to the field of sealing technology for aero-engines and gas turbines, and in particular to a real-time control system for sealing gaps driven by high-temperature shape memory alloys. Background Technology

[0002] In gas turbines and aero engines, the sealing technology of the rotating and stationary disk cavities is crucial for ensuring engine performance and safe operation. Traditional sealing technologies mainly employ brush seals, labyrinth seals, and pouch seals. Among these, pouch seals are widely used due to their non-contact, zero-wear, high-temperature erosion resistance, and minimal weight increase. During the transition from cold start to maximum takeoff speed in gas turbines and aero engines, the seal gap changes under the combined effects of centrifugal force and thermal load. However, traditional pouch seals have a fixed seal gap and cannot actively adjust their sealing performance, resulting in significant variations in sealing effectiveness under different operating conditions. Therefore, to improve sealing efficiency, it is necessary to actively adjust the seal gap under different operating conditions.

[0003] Existing active control systems for sealing gaps based on shape memory alloys regulate the temperature of the shape memory alloy using eddy current tubes. However, this approach suffers from drawbacks such as slow response speed, large sealing gap adjustment delay, and inability to achieve closed-loop control. Furthermore, the staggered connection of the comb-shaped tooth seats in this system leads to increased leakage. The effective shrinkage strain of existing high-temperature shape memory alloys is typically only 3%–4%, requiring a longer shape memory alloy for adjusting the sealing gap using a "direct drive" method. Summary of the Invention

[0004] Objective of the Invention: The technical problem to be solved by this invention is to address the shortcomings of existing technologies by providing a real-time control system for sealing gaps based on high-temperature shape memory alloys. Based on real-time data from a distance sensor, the input current of the high-temperature shape memory alloy located within the annular cooling channel is adjusted. The active gap control unit then drives the sealing ring to move radially, thereby controlling the sealing gap within the target range in real time, achieving active closed-loop control of the sealing gap.

[0005] This invention provides a real-time control system for sealing gaps driven by high-temperature shape memory alloys, including a stator casing, a rotor, a sealing ring assembly, and an active gap control unit;

[0006] The active clearance control unit is installed between the stator casing and the sealing ring assembly, and adjusts the clearance between the sealing ring assembly and the rotor by controlling the radial displacement of the sealing ring assembly;

[0007] The stator casing is provided with an annular cooling channel. The central axis of the annular cooling channel and the central axis of the stator casing are coaxial. Cooling airflow from the compressor flows inside the annular cooling channel.

[0008] The outer edge of the rotor is provided with two or more rows of sieve teeth;

[0009] The sealing ring assembly consists of two or more arc-shaped sealing blocks arranged circumferentially, and the arc-shaped sealing blocks are radially movably mounted on the stator casing.

[0010] The arc-shaped sealing block is connected by an arc-shaped connecting block.

[0011] The arc-shaped sealing block has arc-shaped cavities at both ends, and two symmetrical limiting holes on the outer surface of each end.

[0012] The side and top surfaces of the arc-shaped connecting block are provided with stepped teeth, and four limiting bolts are installed on the top surface of the arc-shaped connecting block. The limiting bolts are installed in the limiting holes.

[0013] The active clearance control unit includes an HTSMA (High Temperature Shape Memory Alloy) actuator and a lever-slider mechanism. The HTSMA actuator is arranged in an annular cooling channel, and the lever-slider mechanism is located between the sealing ring assembly and the stator casing. The two ends of the lever-slider mechanism are respectively connected to the HTSMA actuator and the sealing ring assembly.

[0014] The lever-slider mechanism includes a lever, a base, a groove, and a slider.

[0015] The HTSMA actuator includes a movable baffle, a fixed baffle, a push rod, a pin, a high-temperature shape memory alloy wire, a mechanical return spring, and electrode fixing terminals;

[0016] The movable baffle is installed at the top of the push rod, and the movable baffle can move radially together with the push rod;

[0017] The fixed baffle is installed on the stator housing, and the fixed baffle has a center hole with the same diameter as the push rod.

[0018] The push rod passes through the center hole of the fixed baffle, one end of which is connected to the movable baffle, and the other end is connected to the slider of the lever slider mechanism through a pin.

[0019] The high-temperature shape memory alloy wire is installed between the movable baffle and the fixed baffle. Electrode fixing terminals are installed at both ends of the high-temperature shape memory alloy wire. The deformation of the high-temperature shape memory alloy wire is controlled by changing the input current, thereby pushing the push rod to move.

[0020] The mechanical return spring is installed between the movable baffle and the fixed baffle and is in a compressed state.

[0021] The lever has a sliding groove at each end and a pivot hole on it, through which the lever is connected to the base.

[0022] The slider is embedded inside the groove and connected to the push rod by a pin.

[0023] The lever-slider mechanism amplifies the displacement generated by the high-temperature shape memory alloy wire based on the lever principle, thereby obtaining a larger radial movement stroke of the sealing ring assembly.

[0024] The sealing ring assembly is equipped with a distance sensor, which is located directly above the teeth to measure the sealing gap value in real time.

[0025] The control system uses a real-time active control method to adjust the input current at both ends of the high-temperature shape memory alloy wire in real time based on the sealing gap value obtained from the distance sensor, so as to maintain the sealing gap within the target range.

[0026] The beneficial effects of this invention are as follows: It proposes a real-time control system for sealing gaps driven by high-temperature shape memory alloys. Under the combined action of cooling channels and electric heating, the high-temperature shape memory alloy can achieve rapid and accurate active closed-loop control of the sealing gap based on the signal fed back by the distance sensor. The displacement generated by the driver is amplified by the lever slider mechanism, reducing the length of the high-temperature shape memory alloy and reducing the cooling gas flow rate. The sealing ring adopts a "whole ring segmented + connecting block stepped tooth" structure, which avoids the generation of axial gaps that would lead to increased leakage while achieving radial movement. Attached Figure Description

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0028] Figure 1 This is a schematic diagram of the sealing gap real-time control system according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the HTSMA driver.

[0030] Figure 3 This is a schematic diagram of the lever-slider mechanism.

[0031] Figure 4 This is a schematic diagram of the assembly of the sealing block and the connecting block.

[0032] The following components are labeled in the diagram: 1. Stator casing; 2. Annular cooling channel; 3. Rotor; 4. Grate teeth; 5. Sealing ring assembly; 51. Arc-shaped sealing block; 511. Limiting hole; 52. Arc-shaped connecting block; 521. Stepped teeth; 522. Limiting bolt; 6. Distance sensor; 7. HTSMA driver; 71. Moving baffle; 72. Fixed baffle; 73. Push rod; 74. Pin; 75. High-temperature shape memory alloy wire; 76. Mechanical return spring; 77. Electrode fixing terminal; 8. Lever-slider mechanism; 81. Lever; 82. Base; 83. Slide groove; 84. Slider. Detailed Implementation

[0033] like Figure 1 As shown, this embodiment of the invention proposes a real-time control system for sealing gaps driven by high-temperature shape memory alloy, including a stator casing 1, a rotor 3, a sealing ring assembly 5, and an active gap control unit.

[0034] The stator casing is provided with an annular cooling channel 2. The central axis of the cooling channel and the central axis of the stator casing are coaxial. Cooling airflow from the compressor flows inside the cooling channel.

[0035] The rotor 3 has multiple comb teeth 4 on its outer edge; the sealing ring assembly 5 is composed of multiple arc-shaped sealing blocks arranged circumferentially, and the arc-shaped sealing blocks are radially movably mounted on the stator casing 1.

[0036] The active clearance control unit includes an HTSMA driver 7 and a lever-slider mechanism 8. The HTSMA driver is arranged in an annular cooling channel, and the lever-slider mechanism is located between the sealing ring assembly 5 and the stator housing 1, with its two ends connected to the HTSMA driver 7 and the sealing ring assembly 5, respectively.

[0037] The sealing ring assembly 5 is equipped with a distance sensor 6, which is located directly above the comb teeth and measures the sealing gap value in real time.

[0038] Figure 2This is a schematic diagram of the HTSMA actuator, including a movable baffle 71, a fixed baffle 72, a push rod 73, a pin 74, a high-temperature shape memory alloy wire 75, a mechanical return spring 76, and electrode fixing terminals 77. The movable baffle 71 is mounted on the top of the push rod 73 and can move radially with the push rod 73. The fixed baffle 72 is mounted on the stator housing 1 and has a central hole with the same diameter as the push rod 73. The push rod 73 passes through the central hole of the fixed baffle 72, with one end connected to the movable baffle 71 and the other end connected to the slider 84 of the lever-slider mechanism 8 via the pin 74. The high-temperature shape memory alloy wire 75 is installed between the movable baffle 71 and the fixed baffle 72, with electrode fixing terminals 77 installed at both ends. The movement of the movable baffle 71 is controlled by changing the magnitude of the input current, thereby pushing the push rod 73 to move. The mechanical return spring 76 is installed between the movable baffle 71 and the fixed baffle 72 and is in a compressed state. When the control system fails, it controls the sealing gap to a large gap state.

[0039] Figure 3 The diagram shows the structure of the lever-slider mechanism, which includes a lever 81, a base 82, a groove 83, and a slider 84. Each end of the lever 81 has a groove, and the lever 81 has a pivot hole that connects it to the base 82. The slider 84 is embedded in the groove 83 and is connected to the push rod 73 through a pin 74. The lever-slider mechanism 8 amplifies the displacement generated by the high-temperature shape memory alloy wire 75 according to the lever principle, thereby obtaining a larger radial movement stroke of the sealing ring assembly 5, which reduces the length of the high-temperature shape memory alloy and reduces the amount of cooling air used.

[0040] Figure 4 This is a schematic diagram of the assembly of the sealing block and the connecting block. The sealing ring assembly 5 is composed of multiple arc-shaped sealing blocks 51 arranged circumferentially, and the sealing blocks 51 are connected by arc-shaped connecting blocks 52. The sealing blocks 51 have arc-shaped cavities at both ends, and two symmetrical limiting holes 511 are opened on the outer surface of each end. The side surface and the top surface of the connecting block 52 are provided with stepped teeth 521, and four limiting bolts 522 are installed on the top surface of the connecting block 52. The limiting bolts 522 are installed in the limiting holes 511.

[0041] During the operation of aero-engines and gas turbines, the rotor 3, grating teeth 4, and sealing ring assembly 5 may displace due to temperature changes, vibrations, etc., causing the sealing gap to continuously change. Traditional fixed-gap seals are designed with a large gap value to prevent grating wear, resulting in significant sealing leakage. Existing active gap control methods use vortex tubes to control shape memory alloys to adjust the sealing gap; however, their disadvantages include slow response speed, large gap adjustment delay, and the lack of a gap measuring device, allowing adjustment only according to different operating conditions, and failing to control the sealing gap to the minimum state in real time. The sealing gap real-time control system of this embodiment achieves real-time active closed-loop control through controller control. The controller adjusts the input current at both ends of the high-temperature shape memory alloy wire 75 in real time based on the sealing gap value obtained from the distance sensor 6, thereby adjusting the deformation of the high-temperature shape memory alloy wire 75; the high-temperature shape memory alloy wire 75 drives the push rod 73 to move radially by dragging the moving baffle 71; the radial displacement generated by the push rod 73 is amplified by the lever-slider mechanism 8 and transmitted to the arc-shaped sealing block 51, thereby controlling the sealing gap within the target range.

[0042] Furthermore, the real-time sealing gap control system of this invention can be applied to other non-contact sealing structures of aero engines and gas turbines.

[0043] This invention provides a real-time control system for sealing gaps driven by high-temperature shape memory alloys. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A real-time control system for sealing gaps based on high-temperature shape memory alloy, characterized in that, It includes a stator casing (1), a rotor (3), a sealing ring assembly (5), and an active clearance control unit; The active clearance control unit is installed between the stator casing (1) and the sealing ring assembly (5), and adjusts the clearance between the sealing ring assembly (5) and the rotor (3) by controlling the radial displacement of the sealing ring assembly (5); The stator casing (1) is provided with an annular cooling channel (2), the central axis of the annular cooling channel (2) and the central axis of the stator casing (1) are coaxially arranged, and the cooling airflow from the compressor flows inside the annular cooling channel (2); The rotor (3) has two or more comb teeth (4) on its outer edge; The sealing ring assembly (5) is composed of two or more arc-shaped sealing blocks (51) arranged circumferentially, and the arc-shaped sealing blocks (51) are radially movably mounted on the stator casing (1).

2. The real-time control system for sealing gaps based on high-temperature shape memory alloy driven according to claim 1, characterized in that, The arc-shaped sealing block (51) is connected by an arc-shaped connecting block (52).

3. According to claim 2, the real-time control system for sealing gap driven by high temperature shape memory alloy is provided, wherein the arc-shaped sealing block (51) has arc-shaped cavities at both ends, and two symmetrical limiting holes (511) are provided on the outer surface of each end.

4. According to claim 3, the side surface and the upper surface of the arc-shaped connecting block (52) are set as stepped teeth (521), and four limiting bolts (522) are installed on the upper surface of the arc-shaped connecting block (52), and the limiting bolts (522) are installed in the limiting hole (511).

5. A real-time control system for sealing gaps based on high-temperature shape memory alloy driven according to claim 4, characterized in that, The active clearance control unit includes an HTSMA driver (7) and a lever-slider mechanism (8). The HTSMA driver (7) is arranged in an annular cooling channel (2), and the lever-slider mechanism (8) is located between the sealing ring assembly (5) and the stator casing (1). The two ends of the lever-slider mechanism (8) are connected to the HTSMA driver (7) and the sealing ring assembly (5), respectively.

6. The real-time control system for sealing gaps based on high-temperature shape memory alloy driven according to claim 5, characterized in that, The lever-slider mechanism (8) includes a lever (81), a base (82), a groove (83), and a slider (84).

7. A real-time control system for sealing gaps based on high-temperature shape memory alloy driven according to claim 6, characterized in that, The HTSMA driver (7) includes a movable baffle (71), a fixed baffle (72), a push rod (73), a pin (74), a high-temperature shape memory alloy wire (75), a mechanical return spring (76), and an electrode fixing terminal (77). The movable baffle (71) is installed at the top of the push rod (73), and the movable baffle (71) can move radially together with the push rod (73); The fixed baffle (72) is installed on the stator casing (1), and the fixed baffle (72) has a center hole with the same diameter as the push rod (73); The push rod (73) passes through the center hole of the fixed baffle (72), one end is connected to the movable baffle (71), and the other end is connected to the slider (84) of the lever slider mechanism (8) through the pin (74); The high-temperature shape memory alloy wire (75) is installed between the movable baffle (71) and the fixed baffle (72). Electrode fixing terminals (77) are installed at both ends of the high-temperature shape memory alloy wire (75). The deformation of the high-temperature shape memory alloy wire (75) is controlled by changing the input current, thereby pushing the push rod (73) to move. The mechanical return spring (76) is installed between the movable baffle (71) and the fixed baffle (72) and is in a compressed state.

8. A real-time control system for sealing gaps based on high-temperature shape memory alloy driven according to claim 7, characterized in that, The lever (81) has a sliding groove at each end and a pivot hole on the lever (81). The lever (81) is connected to the base (82) through the pivot hole. The slider (84) is embedded inside the groove (83) and connected to the push rod (73) by a pin (74); The lever-slider mechanism (8) amplifies the displacement generated by the high-temperature shape memory alloy wire (75) according to the lever principle, thereby obtaining a larger radial movement stroke of the sealing ring assembly (5).

9. A real-time control system for sealing gaps based on high-temperature shape memory alloy driven according to claim 8, characterized in that, The sealing ring assembly (5) is equipped with a distance sensor (6), which is located directly above the toothed teeth (4) to measure the sealing gap value in real time.

10. A real-time control system for sealing gaps based on high-temperature shape memory alloy drive according to claim 9, characterized in that, The control system uses a real-time active control method to adjust the input current at both ends of the high-temperature shape memory alloy wire (75) in real time according to the sealing gap value obtained from the distance sensor (6), so as to maintain the sealing gap within the target range.

Images