A turbine pump bladed disk blade gap measurement system and method

Abstract

This invention belongs to the field of measurement technology, specifically relating to a system and method for measuring the blade clearance of a turbopump impeller. It enables rapid, efficient, and high-precision measurement of the blade clearance of a turbopump impeller, meeting current requirements for large-scale testing. This invention accurately acquires distance values ​​using a high-precision fiber optic displacement sensor probe. A motion control mechanism enables the rotation of the turbopump impeller, the rotation of the sensor probe, and reciprocating motion. Through measurement data processing, high-precision measurement of the turbopump impeller blade clearance is ultimately achieved. Specifically, it integrates a precision electric turntable, a precision electric displacement stage, a hollow electric rotary platform, and a 90° outgoing fiber optic displacement sensor probe. A motion controller enables automatic indexing of the turbopump impeller, automatic positioning and rotational scanning of the probe. The clearance of all blades on the entire impeller can be continuously measured after a single clamping, significantly shortening the single-piece inspection time and greatly improving inspection efficiency, meeting the requirements for large-scale factory inspection of turbopump impellers.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology, specifically relating to a system and method for measuring the clearance between turbine pump impeller blades. Background Technology

[0002] The turbopump impeller in a liquid rocket engine is the core rotating component of the turbopump, typically integrating the impeller and the impeller into a single structure. At the pump end, high-speed rotation performs work on the propellant (liquid oxygen, kerosene, liquid hydrogen, etc.), pressurizing and transporting it to provide a stable flow and pressure working fluid for the combustion chamber. At the turbine end, high-temperature, high-pressure combustion gases drive the turbine impeller, converting thermal energy into mechanical energy, which then drives the pump.

[0003] Turbo pump impellers are typically made of nickel-based high-temperature alloys. During operation, the impeller can reach a maximum speed of 30,000 r / min. Operating in a high-speed, high-temperature, high-pressure, and highly corrosive environment, the clearance between adjacent circumferentially distributed turbine pump blades requires strict control. Uneven or significantly deviated clearances directly affect engine performance, reliability, and lifespan; therefore, precise measurements must be performed before delivery.

[0004] The turbine pump impeller has an irregular structure with varying blade profiles. Currently, the methods for measuring the blade clearance of the turbine pump impeller are: (1) Using a high-precision 3D scanner to scan the turbine pump impeller as a whole, and then processing the obtained impeller model through software to finally analyze and obtain the required clearance value between adjacent blades. This method requires expensive scanning equipment and data processing requires high technical skills from personnel; (2) Using a six-degree-of-freedom high-precision coordinate measuring machine, the coordinate measuring head is controlled by programming to slide along the turbine impeller blades to measure and obtain the surface profile of each blade. Finally, the clearance between blades is obtained through data processing. This method has high requirements for the automation of the coordinate measuring machine, and the measurement process is time-consuming and inefficient, which cannot meet the current demand for large-scale inspection. Summary of the Invention

[0005] In view of this, the present invention provides a turbine pump impeller blade clearance measurement system and method, which can realize rapid, efficient and high-precision measurement of turbine pump impeller blade clearance, and meet the current demand for large-scale testing.

[0006] To achieve the objectives of this invention, the following technical solutions are provided: A turbine pump impeller blade clearance measurement system includes: A precision electric rotary table is used to support and drive the impeller of the turbine pump under test to perform indexing rotation. A 90° outgoing fiber optic displacement sensor probe is used to acquire distance signals from the blade surface. A hollow electric rotating platform is used to drive the 90° outgoing fiber optic displacement sensing probe to rotate 360 ​​degrees. A precision electric displacement stage is used to drive the 90° outgoing fiber optic displacement sensing probe to perform reciprocating linear motion. A probe adapter connects the 90° outgoing fiber optic displacement sensing probe to the hollow electric rotary platform. Fiber optic slip rings and fiber optic cables are used to maintain the signal transmission path with the fiber optic displacement sensor data acquisition system when the 90° outgoing fiber optic displacement sensing probe rotates. The motion controller is electrically connected to the precision electric turntable, the precision electric displacement stage, and the hollow electric rotary platform, and is used to coordinate and control the movement of the three to automatically complete the measurement of all blade gaps. The precision electric displacement stage has a moving platform, and the hollow electric rotary platform is fixed on the moving platform. The 90° outgoing fiber optic displacement sensing probe is installed on the rotating part of the hollow electric rotary platform through the probe adapter. The rotor end of the fiber optic slip ring rotates synchronously with the hollow electric rotary platform, and the stator end is fixed to the stationary part of the precision electric displacement stage.

[0007] The motion controller controls the number of reciprocating motions of the precision electric displacement stage and the number of indexing rotations of the precision electric rotary table based on the number of blade gaps in the impeller of the turbine pump being tested, so that both are equal to the number of gaps.

[0008] The present invention also provides a method for measuring the blade clearance of a turbine pump impeller disk based on the system described herein, comprising the following steps: Step 1: Mount the turbine pump impeller to be tested onto the table of the precision electric rotary table, and use a dial indicator to adjust the coaxiality between the turbine pump impeller and the precision electric rotary table to less than or equal to 0.01 mm. Step 2: Program the motion controller according to the number of blade gaps on the turbine pump impeller, so that the number of reciprocating strokes of the precision electric displacement table and the number of rotations of the precision electric rotary table are both equal to the number of gaps. Step 3: Adjust the entire measurement system so that the precision electric displacement stage can drive the 90° outgoing fiber optic displacement sensing probe to the predetermined measurement position and place the probe in the starting position. Step four: Start the measurement. The precision electric displacement stage moves the 90° outgoing fiber optic displacement sensor probe from the starting position to the predetermined measurement position. The hollow electric rotating platform rotates the probe one revolution, and the fiber optic displacement sensor data acquisition system collects data synchronously. After one revolution, the precision electric displacement stage moves the probe back to the starting position, completing the measurement of one gap position. Step 5: The precision electric turntable drives the turbine pump impeller to rotate by one division angle to reach the measurement position corresponding to the next gap. Repeat step 4 to complete the measurement of the current gap position. Step six: Repeat step five until all blade gaps have been measured.

[0009] In step five, the graduation angle is 360 degrees divided by the number of blade gaps.

[0010] In step five, the angle of rotation of the precision electric turntable is automatically calculated and executed by the motion controller based on the set number of gaps.

[0011] Beneficial effects 1. This invention integrates a precision electric turntable, a precision electric displacement stage, a hollow electric rotary platform, and a 90° outgoing fiber optic displacement sensing probe into an automated measurement system. Through a motion controller, it realizes automatic indexing of the turbine pump impeller, automatic positioning and rotation scanning of the probe. All gaps of the entire blade can be continuously measured after one clamping, which significantly shortens the single-piece inspection time, greatly improves the inspection efficiency, and meets the needs of mass turbine pump impeller factory inspection.

[0012] 2. In this invention, a 90° outgoing fiber optic displacement sensing probe is used for non-contact distance measurement. The probe can emit a measurement beam laterally, which can penetrate into the narrow and complex gap area between blades. This effectively avoids the problem of the probe being difficult to reach or interfering with the measured surface in contact measurement, while not scratching the blade surface. High-precision gap data is obtained while ensuring the accessibility of the measurement.

[0013] 3. In this invention, the hollow electric rotating platform drives the probe to complete a 360-degree rotation scan at the measurement position. Combined with the fiber optic displacement sensor data acquisition system, the data is recorded synchronously, which can obtain complete contour information of the blade gap along the circumferential direction. This avoids the deviation caused by single-point or single-direction sampling, and the measurement results are more comprehensive, reliable, and have high repeatability.

[0014] 4. The present invention introduces an optical fiber slip ring to connect the 90° outgoing optical fiber displacement sensing probe to the fixed end acquisition system, ensuring that the optical fiber signal transmission is uninterrupted and untwisted when the probe rotates continuously for a full circle, completely solving the problem of signal line swinging and tangling in traditional rotating parts, and improving the long-term working stability and service life of the measurement system.

[0015] 5. The precision electric turntable, precision electric displacement stage, hollow electric rotary platform, and 90° outgoing fiber optic displacement sensing probe used in this invention are all mature components in the industrial field. The system has a compact structure and the construction cost is far lower than that of high-precision 3D scanners and six-degree-of-freedom coordinate measuring machines. Moreover, the operation process is procedural and automated, which significantly reduces the dependence on the skill level of the operators. While ensuring high measurement accuracy, it achieves excellent economy and practicality.

[0016] 6. The measurement method of this invention clearly stipulates that during installation, a dial indicator should be used to adjust the coaxiality of the blade disk and the turntable to within 0.01 mm, which provides a high-precision rotational reference for the measurement of blade clearance, effectively reducing the system measurement error caused by installation eccentricity, and ensuring the accuracy of the final measurement result from the source. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a turbine pump impeller blade clearance measurement system according to an embodiment of the present invention.

[0018] 1-Precision electric rotary table; 2-Turbine pump impeller; 3-90° output fiber optic displacement sensor probe; 4-Precision electric displacement stage; 5-Probe adapter; 6-Hollow electric rotary platform; 7-Precision electric displacement stage moving platform; 8-Fiber optic slip ring; 9-Fiber optic cable.

[0019] Figure 2 This is a schematic diagram of the method for measuring the blade clearance of a turbine pump impeller disk in an embodiment of the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0021] This invention provides a turbine pump impeller blade clearance measurement system. It accurately acquires distance values ​​using a high-precision fiber optic displacement sensor probe, and a motion control mechanism enables the rotation of the turbine pump impeller, the rotation of the sensor probe, and its reciprocating motion. Through measurement data processing, high-precision measurement of the turbine pump impeller blade clearance is ultimately achieved.

[0022] The system of the present invention is as follows Figure 1 As shown, it includes a precision electric turntable 1, a 90° outgoing fiber optic displacement sensing probe 3, a probe adapter 5, a precision electric displacement stage 4, a hollow electric rotating platform 6, a fiber optic slip ring 8, and a fiber optic cable 9.

[0023] Among them, the precision electric turntable 1 is used to realize the high-precision rotation of the turbine pump impeller 2 under test, the precision electric displacement stage 4 is used to realize the reciprocating motion of the 90° outgoing fiber optic displacement sensing probe 3, the hollow electric rotary platform 6 is used to realize the rotation measurement of the 90° outgoing fiber optic displacement sensing probe 3, the probe adapter 5 is used to realize the connection between the 90° outgoing fiber optic displacement sensing probe 3 and the hollow electric rotary platform 6, and the fiber optic slip ring 8 is used to realize the connection between the 90° outgoing fiber optic displacement sensing probe 3 and the fiber optic displacement sensor data acquisition system. Specifically, a precision electric rotary table is used to support and drive the impeller of the turbine pump under test to rotate in an indexing manner; a 90° outgoing fiber optic displacement sensor probe is used to acquire distance signals from the blade surface; a hollow electric rotary platform is used to drive the 90° outgoing fiber optic displacement sensor probe to rotate 360 ​​degrees; a precision electric displacement stage is used to drive the 90° outgoing fiber optic displacement sensor probe to perform reciprocating linear motion; a probe adapter connects the 90° outgoing fiber optic displacement sensor probe to the hollow electric rotary platform; fiber optic slip rings and fiber optic cables are used to maintain the signal transmission path with the fiber optic displacement sensor data acquisition system when the 90° outgoing fiber optic displacement sensor probe rotates; a motion controller is electrically connected to the precision electric rotary table, the precision electric displacement stage, and the hollow electric rotary platform to coordinate and control the movement of the three components to automatically complete the measurement of all blade gaps. The precision electric displacement stage has a moving platform, the hollow electric rotary platform is fixed on the moving platform, and the 90° outgoing fiber optic displacement sensor probe is mounted on the rotating part of the hollow electric rotary platform through the probe adapter. The rotor end of the fiber optic slip ring rotates synchronously with the hollow electric rotary platform, while the stator end is fixed to the stationary position of the precision electric displacement stage. The motion controller controls the reciprocating strokes of the precision electric displacement stage and the indexing rotations of the precision electric rotary table based on the number of blade gaps in the turbine pump impeller under test, ensuring that both are equal to the number of gaps.

[0024] During measurement, a precision electric turntable 1 drives the turbine pump impeller 2 to rotate, a hollow electric rotary platform 6 drives the 90° outgoing fiber optic displacement sensing probe 3 to rotate 360°, and a precision electric displacement stage 4 drives the one-dimensional reciprocating motion of the 90° outgoing fiber optic displacement sensing probe 3. This combination enables high-precision measurement of the gaps between the blades of the turbine pump impeller 2, solving the problem of balancing detection efficiency and accuracy. The system boasts high measurement accuracy and strong applicability, meeting the blade gap measurement needs of different types of turbine pump impellers.

[0025] Based on the system of this invention, a method for measuring the blade clearance of a turbine pump impeller disk is also proposed, the process of which is as follows: Figure 2 As shown, it includes the following steps: Step 1: Install the turbine pump impeller 2 to be tested onto the rotating table of the precision electric turntable 1, and use a dial indicator to adjust the coaxiality between the turbine pump impeller 2 and the precision electric turntable 1 so that the coaxiality is less than or equal to 0.01mm.

[0026] Step 2: Based on the number of blade gaps in the turbine pump impeller 2, program the motion control system so that the number of reciprocating motions of the precision electric displacement stage 4 is equal to the number of blade gaps in the impeller; and make the number of rotations of the precision electric turntable 1 equal to the number of blade gaps in the impeller (for example, if the turbine pump impeller has 12 gaps, then the precision electric turntable rotates 30° each time).

[0027] Step 3: Based on the blade clearance measurement position of the turbine pump impeller 2, adjust the entire measurement system so that the precision electric displacement stage 4 can drive the 90° outgoing fiber optic displacement sensor probe 3 to the designated measurement position, and then adjust the 90° outgoing fiber optic displacement sensor probe 3 to the starting position.

[0028] Step four: Measurement begins. The precision electric displacement stage 4 moves the 90° outgoing fiber optic displacement sensor probe 3 to the designated measurement position. The hollow electric rotary platform 6 rotates the 90° outgoing fiber optic displacement sensor probe 3 one revolution. At this time, the fiber optic displacement sensor data acquisition system synchronously collects data. After one revolution, the measurement ends at the current measurement position, and the precision electric displacement stage 4 moves the 90° outgoing fiber optic displacement sensor probe 3 back to the starting position.

[0029] Step 5: The precision electric turntable 1 drives the turbine pump impeller 2 to rotate at a certain angle to reach the next gap measurement position. Repeat step 4 above to complete the measurement of the current point.

[0030] Step six: Repeat step five above until all blade gap measurements are completed, then end the measurement.

[0031] This invention includes, but is not limited to, the above embodiments. Any equivalent substitutions or partial improvements made under the spirit and principles of this invention shall be considered within the scope of protection of this invention.

Claims

1. A turbine pump impeller blade clearance measurement system, characterized in that, include: A precision electric rotary table is used to support and drive the impeller of the turbine pump under test to perform indexing rotation. A 90° outgoing fiber optic displacement sensor probe is used to acquire distance signals from the blade surface. A hollow electric rotating platform is used to drive the 90° outgoing fiber optic displacement sensing probe to rotate 360 ​​degrees. A precision electric displacement stage is used to drive the 90° outgoing fiber optic displacement sensing probe to perform reciprocating linear motion. A probe adapter connects the 90° outgoing fiber optic displacement sensing probe to the hollow electric rotary platform. Fiber optic slip rings and fiber optic cables are used to maintain the signal transmission path with the fiber optic displacement sensor data acquisition system when the 90° outgoing fiber optic displacement sensing probe rotates. The motion controller is electrically connected to the precision electric turntable, the precision electric displacement stage, and the hollow electric rotary platform, and is used to coordinate and control the movement of the three to automatically complete the measurement of all blade gaps. The precision electric displacement stage has a moving platform, and the hollow electric rotary platform is fixed on the moving platform. The 90° outgoing fiber optic displacement sensing probe is installed on the rotating part of the hollow electric rotary platform through the probe adapter. The rotor end of the fiber optic slip ring rotates synchronously with the hollow electric rotary platform, and the stator end is fixed to the stationary part of the precision electric displacement stage.

2. The turbine pump impeller blade clearance measurement system according to claim 1, characterized in that, The motion controller controls the number of reciprocating strokes of the precision electric displacement stage and the number of indexing rotations of the precision electric rotary table based on the number of blade gaps in the impeller of the turbine pump being tested, so that both are equal to the number of gaps.

3. A method for measuring the blade clearance of a turbine pump impeller disk based on the system described in claim 1 or 2, characterized in that, Includes the following steps: Step 1: Mount the turbine pump impeller to be tested onto the table of the precision electric rotary table, and use a dial indicator to adjust the coaxiality between the turbine pump impeller and the precision electric rotary table to less than or equal to 0.01 mm. Step 2: Program the motion controller according to the number of blade gaps on the turbine pump impeller, so that the number of reciprocating strokes of the precision electric displacement table and the number of rotations of the precision electric rotary table are both equal to the number of gaps. Step 3: Adjust the entire measurement system so that the precision electric displacement stage can drive the 90° outgoing fiber optic displacement sensing probe to the predetermined measurement position and place the probe in the starting position. Step four: Start the measurement. The precision electric displacement stage moves the 90° outgoing fiber optic displacement sensor probe from the starting position to the predetermined measurement position. The hollow electric rotating platform rotates the probe one revolution, and the fiber optic displacement sensor data acquisition system collects data synchronously. After one revolution, the precision electric displacement stage moves the probe back to the starting position, completing the measurement of one gap position. Step 5: The precision electric turntable drives the turbine pump impeller to rotate by one division angle to reach the measurement position corresponding to the next gap. Repeat step 4 to complete the measurement of the current gap position. Step six: Repeat step five until all blade gaps have been measured.

4. The method for measuring the blade clearance of a turbine pump impeller disk according to claim 3, characterized in that, The graduation angle mentioned in step five is 360 degrees divided by the number of blade gaps.

5. The method for measuring the blade clearance of a turbine pump impeller disk according to claim 4, characterized in that, In step five, the angle of rotation of the precision electric turntable each time is automatically calculated and executed by the motion controller based on the set number of gaps.

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