Blade top gap adjusting device

Abstract

The embodiment of the invention provides a blade tip clearance adjusting device. The blade tip clearance adjusting device comprises a turbine cylinder, a partition plate, an outer ring, turbine rotor blades and a mechanical driving device. The partition plate is fixedly installed in the turbine cylinder. The outer ring is assembled on the partition plate, and the outer ring is divided into a plurality of independent outer ring sections in the circumferential direction of the turbine cylinder; the turbine rotor blade is mounted on the turbine rotor; and the mechanical driving device is arranged between the outer ring and the partition plate and is in driving connection with each outer ring section. The mechanical driving device is used for driving all the outer ring sections to move in the radial direction of the turbine cylinder so as to change the radial position of the outer surface, and therefore the size of the blade top gap is adjusted. Turbine efficiency in the operation process can be improved, and gas turbine power consumption is reduced.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of gas turbine technology, specifically relating to a blade tip clearance adjustment device. Background Technology

[0002] In the field of gas turbines, the tip clearance of turbine rotor blades has a significant impact on the efficiency and power consumption of components and the entire machine. Generally, the smaller the clearance, the lower the flow loss at the blade tip, resulting in greater benefits. However, gas turbine rotors and cylinders undergo thermal expansion during operation, and the deformation varies between different materials and temperature ranges. Therefore, the tip clearance of turbine rotor blades changes during gas turbine start-up and shutdown. Maintaining a fixed and as small a clearance as possible is extremely difficult, especially in the frequent start-up and shutdown operation mode of heavy-duty gas turbines, where controlling the tip clearance of turbine rotor blades is a major challenge. For the safe and reliable operation of gas turbines, a tip clearance control requirement is generally set for the tip clearance of turbine rotor blades, and this requirement is measured and confirmed during maintenance to ensure that it meets the specified range.

[0003] In related technologies, active clearance control technology has begun to be applied to adjust the tip clearance of turbine rotor blades to obtain high turbine efficiency under operating conditions. A typical technology is gas turbine hydraulic clearance optimization technology. Its basic principle is: when the gas turbine starts up and the tip clearance of the turbine rotor blades remains unchanged, the hydraulic device is activated to move the rotor axially along the contraction direction of the turbine flow passage (the direction of the gas turbine inlet), thereby reducing the tip clearance of the turbine rotor blades and thus obtaining higher turbine efficiency and gas turbine efficiency.

[0004] While the aforementioned technology achieves the desired effect, its method of axially moving the rotor presents certain problems: axial movement of the entire rotor alters not only the tip clearance of the turbine rotor blades but also affects the tip clearance of the compressor rotor blades. Generally, the flow path of a compressor contracts along the airflow direction; conversely, with the rotor moving axially in the same direction, the tip clearance of the turbine rotor blades decreases, while the tip clearance of the compressor rotor blades increases. This negatively impacts compressor efficiency, meaning that while improving turbine efficiency, it also leads to a decrease in compressor efficiency. Therefore, there is an urgent need for a turbine rotor blade tip clearance adjustment device to solve these problems, so as to improve turbine efficiency without affecting the performance and efficiency of other components. Summary of the Invention

[0005] The embodiments disclosed herein are intended to at least address one of the technical problems existing in the prior art, and to provide a blade tip clearance adjustment device.

[0006] Embodiments of this disclosure provide a blade tip clearance adjustment device, the blade tip clearance adjustment device comprising: Turbine cylinder; A partition plate, which is fixedly installed inside the turbine cylinder; The outer ring is assembled on the partition plate and is divided into multiple independent outer ring segments along the circumferential direction of the turbine cylinder; Turbine rotor blades, the turbine rotor blades being mounted on a turbine rotor; A mechanical drive device is disposed between the outer ring and the partition plate and is drivenly connected to each of the outer ring segments; wherein... The outer surface of the outer ring is opposite to the tip of the turbine rotor blade to form a tip gap between the outer surface and the tip; the mechanical drive device is used to drive each of the outer ring segments to move radially along the turbine cylinder to change the radial position of the outer surface, thereby adjusting the size of the tip gap.

[0007] Optionally, a stepped staggered structure is used between two adjacent outer ring segments, so that a circumferential gap is formed between the radial surfaces of the two adjacent outer ring segments and the circumferential surfaces maintain contact.

[0008] Optionally, the circumferential gap ranges from 1.5mm to 3mm; the cross-sectional profile of the circumferential surface is a spline curve shape, the two ends of which are tangent to the radial surface by circular arcs, and the middle part is a quadratic spline shape with one end higher than the other.

[0009] Optionally, the number of outer ring segments is set to 40 to 60, and the outer ring segments are evenly distributed in the upper and lower cylinders of the turbine cylinder.

[0010] Optionally, the outer surface of the outer ring is configured as a profile surface adapted to the tip shape of the turbine rotor blade.

[0011] Optionally, the mechanical drive device includes: Multiple actuators are provided, each corresponding to one of the outer ring segments, and each actuator is fixedly connected to a corresponding outer ring segment by bolts. Multiple position sensors are provided on the outer ring to monitor the radial position of each outer ring segment and obtain a real-time blade tip clearance signal. A controller electrically connected to the actuator and the position sensor is used to calculate and issue a radial movement command to the actuator based on the difference between the target tip clearance value and the real-time tip clearance signal.

[0012] Optionally, the controller is configured to: send a uniform radial movement command to each of the actuators to achieve overall synchronous control of each of the outer loop segments; and / or, send independent radial movement commands to one or more specified actuators to achieve independent control of one or more of the local outer loop segments.

[0013] Optionally, the outer ring is coated with a thermal barrier coating.

[0014] Optionally, a toothed sealing structure is provided on the assembly surface of the partition and the outer ring.

[0015] The tip clearance adjustment device of the present disclosure realizes tip clearance control during gas turbine operation by controlling the radial movement of the outer ring. It can realize rapid response adjustment of the clearance according to the target tip clearance value, improve turbine efficiency during operation, and reduce gas turbine power consumption. Attached Figure Description

[0016] Figure 1 This is an isometric schematic diagram of a blade tip clearance adjustment device according to an embodiment of the present disclosure; Figure 2 This is a right-side schematic diagram of the blade tip clearance adjustment device; Figure 3 for Figure 2 AA-line cross-section; Figure 4 (a) is a partial isometric view of the outer ring. Figure 4 (b) is Figure 4 (a) Front view diagram; Figure 5 for Figure 4 (b) BB line profile; Figure 6 (a) is a schematic diagram showing the movement of the outer ring along one side of the radial direction. Figure 6 (b) is a schematic diagram of the outer ring moving along the other side of the radial direction. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figures 1 to 6As shown, a blade tip clearance adjustment device includes a turbine cylinder 110, a diaphragm 120, an outer ring 130, turbine rotor blades 140, and a mechanical drive device 150. The diaphragm 120 is fixedly installed inside the turbine cylinder 110. The outer ring 130 is mounted on the diaphragm 120 and is divided into multiple independent outer ring segments 131 along the circumferential direction of the turbine cylinder 110. The turbine rotor blades 140 are mounted on a turbine rotor (not shown). The mechanical drive device 150 is located between the outer ring 130 and the diaphragm 120 and is drivenly connected to each of the outer ring segments 131.

[0019] The outer surface 132 of the outer ring 130 is opposite to the blade tip 141 of the turbine rotor blade 140, so as to form a blade tip gap between the outer surface 132 and the blade tip 141. The mechanical drive device 150 is used to drive each of the outer ring segments 131 to move radially along the turbine cylinder 110, so as to change the radial position of the outer surface 132, thereby adjusting the size of the blade tip gap.

[0020] Specifically, such as Figures 1 to 6 As shown, embodiments of this disclosure provide a blade tip clearance adjustment device for a gas turbine, including a turbine cylinder 110, a diaphragm 120, an outer ring 130, turbine rotor blades 140, and a mechanical drive device 150. The turbine cylinder 110 is the outer housing of the entire device. The diaphragm 120 is fixedly installed inside the turbine cylinder 110, serving as the basic structure for load-bearing and positioning. The outer ring 130 is mounted on the diaphragm 120, with its outer surface 132 facing the blade tip 141 of the turbine rotor blade 140; the distance between them constitutes the blade tip clearance to be adjusted. The turbine rotor blades 140 are fixedly installed on the turbine rotor and rotate with it. The mechanical drive device 150 is disposed between the diaphragm 120 and the outer ring 130, and is used to drive the outer ring 130 to move radially along the turbine cylinder 110. The outer ring 130 is not a single integral ring, but is divided into multiple independent outer ring segments 131 along the circumferential direction.

[0021] Furthermore, the number of outer ring segments 131 is set to 40 to 60, and the outer ring segments 131 are evenly distributed in the upper and lower cylinders of the turbine cylinder 110. The outer surface 132 of the outer ring 130 is set as a contour surface that matches the shape of the blade tip 141 of the turbine rotor blade 140.

[0022] Specifically, the number of outer ring segments 131 can be set to 40 to 60, such as 48 or 50, and the outer ring segments 131 are evenly distributed on the upper and lower cylinders of the turbine cylinder 110. The outer surfaces 132 of all the outer ring segments 131 together form a complete cylindrical profile surface, wherein the outer surface 132 of each outer ring segment 131 is adapted to the shape of the tip 141 of the turbine rotor blade 140.

[0023] For example, such as Figure 5 As shown, the two adjacent outer ring segments 131 are fitted with a stepped staggered structure, so that a circumferential gap is formed between the radial surfaces 133 of the two adjacent outer ring segments 131, and the circumferential surfaces 134 are in contact fit.

[0024] Specifically, such as Figure 5 As shown, a circumferential gap is maintained between the corresponding radial surfaces 133 of two adjacent outer ring segments 131. This circumferential gap can be set from 1.5mm to 3mm, such as 1.8mm or 2.2mm. Simultaneously, the corresponding circumferential surfaces 134 of two adjacent outer ring segments 131 are in close contact. The advantage of this design is that when the outer ring segment 131 is driven to move radially (e.g., ...), ... Figure 6 As shown, the circumferential gap between adjacent outer ring sections 131 will change slightly, but the circumferential surfaces 134 will always maintain contact or a very small gap fit, thereby allowing radial adjustment while minimizing the leakage of high-temperature gas through the gap between the outer ring sections 131.

[0025] Furthermore, the cross-sectional profile of the circumferential surface 134 is a spline curve shape. The two ends of this spline curve smoothly transition tangent to the radial surface 133 with circular arcs, while the middle portion exhibits a quadratic spline shape with one end higher than the other. The cross-sectional profile of the circumferential surface 134 (i.e., the cross-sectional shape perpendicular to the airflow direction) is designed as a special spline curve. The two ends of this spline curve smoothly transition tangent to the radial surface 133 with circular arcs, while the middle portion exhibits a quadratic spline shape with one end higher than the other. This streamlined design helps guide airflow and further reduces flow losses.

[0026] For example, the mechanical drive device 150 can be driven by an electro-mechanical or electromagnetic drive method. For instance, using an electro-mechanical drive method, the mechanical drive device 150 includes multiple actuators, multiple position sensors, and a controller. Each actuator corresponds one-to-one with one of the outer ring segments 131, and each actuator is fixedly connected to a corresponding outer ring segment 131 by bolts. The position sensors are located on the outer ring 130 to monitor the radial position of each outer ring segment 131 to obtain a real-time tip clearance signal. The controller is electrically connected to the actuators and the position sensors. The controller calculates and issues a radial movement command to the actuators based on the difference between the target tip clearance value and the real-time tip clearance signal.

[0027] Specifically, the actuators are one-to-one with the number of outer ring segments 131. Each actuator is fixedly connected to its corresponding outer ring segment 131 by bolts, responsible for driving the precise radial movement of that outer ring segment 131. Position sensors can be redundantly arranged and installed on the outer ring segments 131 or at the drive connection points to monitor the actual radial position of each outer ring segment 131 in real time with high precision and feed the signal back to the controller. The controller is located outside the turbine cylinder 110. It receives the real-time tip clearance signal monitored by the position sensors and compares it with the preset optimal target tip clearance value. Based on the difference between the two, the controller calculates the required radial movement amount and direction (inward reduction of clearance or outward increase of clearance) for each outer ring segment 131, and then issues a radial movement command to the corresponding actuator.

[0028] Furthermore, the controller is configured to: send a uniform radial movement command to each of the actuators to achieve overall synchronous control of each of the outer loop segments 131; and / or, send independent radial movement commands to one or more specified actuators to achieve independent control of one or more local outer loop segments 131.

[0029] Specifically, the controller has two control modes: Overall synchronous control: This sends the same movement command to all actuators, causing all outer ring sections 131 to move synchronously and in the same amount, used to handle uniform tip clearance variations. Local independent control: This allows sending different movement commands to one or several actuators in the outer ring sections 131 individually. This mode is used to address situations where the circumferential distribution of tip clearance is uneven due to slight rotor eccentricity, cylinder deformation, etc., by specifically adjusting areas with excessively small tip clearances to ensure operational safety.

[0030] For example, the outer ring 130 is coated with a thermal barrier coating. Its main function is to resist high-temperature combustion gases and protect the substrate material of the outer ring 130. At the same time, the thermal barrier coating also provides a certain safety margin. In the event of extremely minor blade tip abrasion, the coating can be worn down first, buying time for subsequent intervention and adjustment.

[0031] For example, such as Figure 3 As shown, a toothed sealing structure 121 is provided on the assembly surface of the partition 120 and the outer ring 130. When the outer ring 130 moves radially, the toothed sealing structure 121 can effectively maintain the seal between the partition 120 and the outer ring 130, preventing the main gas flow from leaking into the back cavity.

[0032] The following describes the working process of the blade tip clearance adjustment device using a single start-up and shutdown process of a gas turbine: Initial cold state: After the gas turbine is shut down and cooled, all outer ring sections are in the "zero position" (position sensor readings return to zero), and the blade tip clearance is the preset cold state design value.

[0033] Start-up and loading process (non-steady-state condition): During gas turbine startup, the rotor and cylinder begin uneven thermal expansion, and the blade tip clearance changes dynamically (usually decreasing first and then increasing). The controller compares the real-time measured blade tip clearance with the optimal target blade tip clearance value under the current operating condition. Once the difference exceeds a set threshold, the controller immediately calculates the required radial displacement.

[0034] The controller sends commands to the actuator. For example, if the current clearance is less than the target value, the outer loop is instructed to move radially outward to increase the clearance and avoid rubbing. Conversely, it moves inward to decrease the clearance and improve efficiency. The position sensor provides real-time feedback on the actual position of the outer loop, forming a closed-loop control until the blade tip clearance reaches the target range.

[0035] Steady-state operation: When the unit enters stable load operation, the blade tip clearance also tends to stabilize. The controller adjusts the outer loop section to the optimal clearance position under this steady-state condition and maintains it. At this time, the system allows for a slightly longer response delay, responding only to slow changes exceeding the threshold, in order to reduce unnecessary mechanical wear and energy consumption.

[0036] Shutdown process: As the gas turbine shuts down and the temperature drops, the rotor and cylinder block contract, and the blade tip clearance changes dynamically again. The device continues to operate, dynamically adjusting the position of the outer ring section according to the target clearance curve during shutdown. This continues until the cylinder block is completely cooled, and all outer ring sections return to their initial cold-state positions.

[0037] The disclosed tip clearance adjustment device achieves precise, active, radial, rapid, and locally adjustable control of the tip clearance. Compared to the axially moving rotor scheme mentioned in the background art, this scheme only adjusts the outer ring of the turbine section, without any negative impact on compressor efficiency. The special stepped outer ring structure effectively suppresses gas leakage while ensuring mobility. The staged and mode-based control strategy balances adjustment accuracy, response speed, and economy. Ultimately, this device enables the tip clearance to be maintained near the ideal value for most of the operating time, significantly reducing tip leakage losses and improving turbine and overall system efficiency.

[0038] like Figures 1 to 6 As shown, the working principle of the blade tip clearance adjustment device is as follows: During the operation of the gas turbine, the controller of the mechanical drive device 150 calculates the radial movement of the outer ring 130 based on the real-time blade tip clearance and the target blade tip clearance value. The radial movement direction is determined according to the radial position of the outer ring 130 under the target blade tip clearance. After inputting the radial movement command, the outer ring 130 is driven to move through the drive actuator. The position sensor monitors the radial position of the outer ring 130 and measures the actual radial movement distance. After reaching the target radial movement amount, the action stops and the current radial position of the outer ring 130 is maintained.

[0039] The radial movement of the outer ring 130 can be controlled as a whole or individually, adapting to situations such as circumferential unevenness in the blade tip clearance. The mechanical drive device 150 has a fast response, meeting the needs of rapid changes in the blade tip clearance of the turbine rotor blades 140 during gas turbine operation. During the radial movement of the outer ring 130, circumferential surface contact and fit can be achieved, while a circumferential clearance is left on the radial surface, ensuring safe operation of the outer ring 130 and reducing flow leakage losses. In addition, the diaphragm 120 is equipped with a grate-tooth sealing structure 121 to maintain the seal between the outer ring 130 and the diaphragm 120 during the radial movement of the outer ring 130, preventing airflow leakage into the outer ring 130 area. Through the above process, the blade tip clearance of the turbine rotor blades 140 can be rapidly adjusted, keeping the clearance value near the target value and improving the efficiency of the gas turbine.

[0040] When the machine is stopped, the radial position of the outer ring 130 is in the cold tip clearance state, and the position sensor indicates 0.

[0041] After the gas turbine starts up, the blade tip clearance initially decreases and then increases due to the different thermal expansion rates of the turbine rotor and turbine cylinder 110. Therefore, the radial position of the outer ring 130 is adjusted based on the calculation result of subtracting the real-time blade tip clearance from the target blade tip clearance value, allowing the blade tip clearance to quickly respond to a value near the target blade tip clearance, thus improving turbine efficiency. During the radial movement, the circumferential surfaces 134 of the outer ring 130 maintain contact or a minimal clearance fit without rubbing against each other, while the circumferential clearance between the radial surfaces 133 decreases or increases accordingly. This proposed outer ring structure reduces gas turbine airflow leakage to the outer ring region, ensuring turbine efficiency.

[0042] When the gas turbine reaches steady-state operation, the blade tip clearance is stable. The radial position of the outer ring 130 is adjusted to bring the blade tip clearance close to the target value under steady-state conditions, and this radial position remains unchanged thereafter. Under steady-state conditions, the mechanical drive device 150 is allowed a certain time delay before starting operation. During gas turbine start-up, shutdown, and unsteady-state conditions with varying loads, immediate response is required. The radial position of the outer ring 130 is fine-tuned based on the real-time changes in the blade tip clearance value. For example, when the change in blade tip clearance is less than 0.3 mm, the clearance adjustment device is not activated to reduce device wear and increased power consumption due to frequent use, ensuring economic efficiency.

[0043] After the gas turbine begins to shut down, the blade tip clearance adjustment device remains engaged, adjusting the radial position of the outer ring 130 in real-time according to the blade tip clearance changes during the shutdown process to ensure that the blade tip clearance is near the target blade tip clearance during shutdown. Once the cylinder block temperature drops to a cold state after shutdown, the outer ring 130 synchronously returns to the cold blade tip clearance state.

[0044] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A blade tip clearance adjustment device, characterized in that, The blade tip clearance adjustment device includes: Turbine cylinder; A partition plate, which is fixedly installed inside the turbine cylinder; The outer ring is assembled on the partition plate and is divided into multiple independent outer ring segments along the circumferential direction of the turbine cylinder; Turbine rotor blades, the turbine rotor blades being mounted on a turbine rotor; A mechanical drive device is disposed between the outer ring and the partition plate and is drivenly connected to each of the outer ring segments; wherein... The outer surface of the outer ring is opposite to the tip of the turbine rotor blade to form a tip gap between the outer surface and the tip; the mechanical drive device is used to drive each of the outer ring segments to move radially along the turbine cylinder to change the radial position of the outer surface, thereby adjusting the size of the tip gap.

2. The blade tip clearance adjusting device according to claim 1, characterized in that, The two adjacent outer ring segments are fitted with a stepped staggered structure, so that a circumferential gap is formed between the radial surfaces of the two adjacent outer ring segments and the circumferential surfaces are in contact.

3. The blade tip clearance adjusting device according to claim 2, characterized in that, The circumferential gap ranges from 1.5mm to 3mm; the cross-sectional profile of the circumferential surface is a spline curve shape, with both ends of the spline curve tangent to the radial surface by circular arcs, and the middle part having a quadratic spline shape with one end higher than the other.

4. The blade tip clearance adjusting device according to claim 1, characterized in that, The number of outer ring segments is set to 40 to 60, and the outer ring segments are evenly distributed in the upper and lower cylinders of the turbine cylinder.

5. The blade tip clearance adjusting device according to claim 1, characterized in that, The outer surface of the outer ring is configured as a profile surface that matches the tip shape of the turbine rotor blade.

6. The blade tip clearance adjusting device according to any one of claims 1 to 5, characterized in that, The mechanical drive device includes: Multiple actuators are provided, each corresponding to one of the outer ring segments, and each actuator is fixedly connected to a corresponding outer ring segment by bolts. Multiple position sensors are provided on the outer ring to monitor the radial position of each outer ring segment and obtain a real-time blade tip clearance signal. A controller electrically connected to the actuator and the position sensor is used to calculate and issue a radial movement command to the actuator based on the difference between the target tip clearance value and the real-time tip clearance signal.

7. The blade tip clearance adjusting device according to claim 6, characterized in that, The controller is configured to: send a uniform radial movement command to each of the actuators to achieve overall synchronous control of each of the outer loop segments; and / or, send independent radial movement commands to one or more specified actuators to achieve independent control of one or more of the local outer loop segments.

8. The blade tip clearance adjusting device according to claim 1, characterized in that, The outer ring is coated with a thermal barrier coating.

9. The blade tip clearance adjusting device according to claim 1, characterized in that, A toothed sealing structure is provided on the assembly surface of the partition and the outer ring.

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