Gas turbine compressor blade tip clearance flow field tracer particle loading system and loading method

Abstract

The present application relates to a kind of gas engine compressor blade tip clearance flow field tracer particle loading system and loading method, system includes: high light transmission optical window, tracer particle loading port, tracer particle generation module, tracer particle automatic loading control module, laser sheet light source and tracer particle image recording camera.Tracer particle loading port is located between blade and stator, it is arranged as rectangular slit, tracer particle loading port exit is acute angle with casing wall face;Tracer particle generation module includes pressure stabilizing source, gas source pressure gauge, tracer particle flowmeter and ultrasonic tracer particle generator;Tracer particle automatic loading control module includes controller, photoelectric detector, tracer particle loading electric valve and pipeline purging control electric valve.The system of the present application ensures that tracer particle sticks casing wall face and flows into blade tip clearance test flow field area, automatically judges optical window contamination, can be automatically cleaned without shutdown, thereby reduce test cost, improve test efficiency.

Description

Technical Field

[0001] This invention relates to a flow field testing technology for gas turbine compressors, and particularly to a particle loading system and method for tracing the flow field at the tip clearance of a gas turbine compressor blade. Background Technology

[0002] The instability mechanism of compressors is closely related to the unsteady flow in the blade tip clearance region. This unsteady phenomenon is a result of vortex motion caused by tip leakage or the self-induced effect of the interaction between the leakage flow and the mainstream flow. Therefore, monitoring the flow field in the blade tip clearance is crucial in the study of compressor flow instability mechanisms.

[0003] With the development of lasers, photodetectors, and image processing technologies, various non-contact flow field visualization measurement techniques have emerged, such as laser Doppler velocimetry, particle image velocimetry, and holographic three-dimensional velocimetry. These non-contact optical flow field measurement techniques require loading tracer particles into the flow field, and the velocity of the tracer particles reflects the velocity of the flow field. Due to the small space at the blade tip clearance (hundreds of micrometers to millimeters) and the complexity of the flow field, loading tracer particles is very challenging. Existing tracer particle loading methods are divided into two types: one is full-field loading, where tracer particles are scattered at the compressor intake, filling the entire flow channel, requiring a large quantity of tracer particles; the other is local loading upstream of the measurement area, where the location is difficult to determine.

[0004] Due to the complexity of the flow field in the blade tip gap region, the optical window is easily contaminated, which leads to a decrease in the imaging quality of the tracer particles. It is necessary to stop the machine for cleaning, which greatly reduces the experimental efficiency. At the same time, the frequent start-up and shutdown of the experimental equipment reduces the service life of the equipment and increases the experimental cost. Summary of the Invention

[0005] To address the current problems in monitoring the flow field of gas turbine compressor blade tip clearance, a tracer particle loading system and method for gas turbine compressor blade tip clearance flow field are proposed. The system ensures that the tracer particles flow along the casing wall into the blade tip clearance test flow field area, and can automatically determine the contamination status of the optical window and clean the contaminated optical window, thereby achieving efficient loading of tracer particles for the gas turbine compressor blade tip clearance flow field.

[0006] The technical solution of this invention is as follows: a tracer particle loading system for the tip clearance flow field of a gas turbine compressor, wherein rotating blades and stationary blades are placed inside a cylindrical casing, and a high-transmittance optical window is embedded in the sealed opening of the casing. The inner wall of the high-transmittance optical window is flush with the inner wall of the casing. A tracer particle loading port is opened on one side of the high-transmittance optical window. The high-transmittance optical window and the tracer particle loading port are located upstream of the tip clearance flow field measurement area inside the casing. A laser sheet light source emits laser light to directly irradiate the tip clearance flow field measurement area. A tracer particle generating module is connected to the tracer particle loading port through a conduit. Under the control of the tracer particle automatic loading control module, tracer particles with a flow rate are generated. The tracer particles are uniformly added to the tip clearance flow field measurement area through the tracer particle loading port. A tracer particle image recording camera is located outside the casing and acquires images of the tracer particle activity in the tip clearance flow field measurement area inside the casing through the high-transmittance optical window.

[0007] Preferably, the tracer particle loading port is located between the rotating blade and the stationary blade. The tracer particle loading port has three connection ports arranged sequentially along the blade arrangement direction. The three connection ports are used to communicate with the output port conduit of the tracer particle generating module. The tracer particles enter through the straight holes in the three connection ports, and then flow into the inclined rectangular slit in the tracer particle loading port for mixing before being sent into the casing.

[0008] Preferably, the rectangular slit in the tracer particle loading port is 3mm wide, with the wide side of the slit corresponding to the circumferential direction of the casing and the narrow side corresponding to the axial direction of the casing. The outlet of the rectangular slit forms an acute angle with the inner wall of the casing, so that the tracer particles flow along the casing wall and enter the flow field measurement area of ​​the blade tip gap.

[0009] Preferably, the rectangular slit outlet forms an acute angle with the inner wall of the casing, with the acute angle ranging from 40°±5°, and the rectangular slit outlet has a 4° expansion angle.

[0010] Preferably, the tracer particle generating module includes a pressure-stabilized gas source, a tracer particle flow meter, and an ultrasonic tracer particle generator. The tracer particles from the ultrasonic tracer particle generator are carried into the tracer particle loading port by the pressure-stabilized gas source, and the tracer particle flow meter calculates the velocity of the tracer particles at the rectangular slit outlet in the tracer particle loading port.

[0011] Preferably, the ultrasonic tracer particle generator uses pure water as the working medium to generate liquid mist tracer particles, and the size and number of tracer particles are adjusted by the ultrasonic frequency and power.

[0012] Preferably, the tracer particle automatic loading control module includes a controller, a photodetector, a tracer particle loading electric valve, and a pipeline purging control electric valve. The tracer particle loading electric valve is connected between the regulated gas source and the ultrasonic tracer particle generator. The controller controls the concentration of tracer particles by adjusting the opening of the tracer particle loading electric valve and the power of the ultrasonic tracer particle generator. The pipeline purging control electric valve is connected to the output pipeline of the regulated gas source. The photodetector monitors whether a liquid film is formed at the rectangular slit outlet of the tracer particle loading port.

[0013] A method for loading tracer particles into the flow field of the blade tip clearance of a gas turbine compressor includes the following steps:

[0014] 1) Establish a particle loading system for tracing the flow field at the tip clearance of a gas turbine compressor blade.

[0015] 2) The test equipment has reached the test conditions and is operating stably;

[0016] 3) Activate the tracer particle generation module to load tracer particles;

[0017] 4) A liquid film was detected forming at the outlet of the tracer particle loading port;

[0018] 5) If a liquid film is present, stop the laser output and camera recording, turn off the ultrasonic tracer particle generator, and open the pipeline purging control electric valve.

[0019] 6) After the high-transmittance optical window and the liquid film in the pipeline are cleaned, the tracer particles are loaded again.

[0020] 7) Adjust the amount of tracer particles loaded based on the recording results;

[0021] 8) The test is completed after multiple cycles;

[0022] 9) After the test, the pipeline was purged.

[0023] The beneficial effects of the present invention are as follows: The tracer particle loading system and loading method for the flow field of the gas turbine compressor blade tip gap of the present invention can effectively load tracer particles into the test flow field area, automatically judge the contamination of the optical window, and automatically clean it without stopping the machine, thereby reducing the test cost and improving the test efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram showing the working state of the rotating blades and stationary blades in a compressor.

[0025] Figure 2 This is a schematic diagram of the composition of the gas turbine compressor blade tip clearance flow field tracer particle loading system of the present invention;

[0026] Figure 3 A schematic diagram of the tracer particle loading port structure in the system of this invention;

[0027] Figure 4 A schematic diagram of the tracer particle loading channel structure in the system of this invention. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0029] like Figure 1 This is a schematic diagram showing the working state of the rotating blades and stationary blades in a compressor, which are housed within a cylindrical casing. Figure 2 The diagram shown is a schematic of the composition of a gas turbine compressor blade tip gap flow field tracer particle loading system according to this embodiment. The system includes: a high-transmittance optical window 1, a tracer particle loading port 4, a tracer particle generation module, a tracer particle automatic loading control module, a laser sheet light source 7, and a tracer particle image recording camera 8. A high-transmittance optical window 1 is embedded in the sealed opening of the casing. The inner wall of the high-transmittance optical window 1 is flush with the inner wall of the casing. A tracer particle loading port 4 is opened on one side of the high-transmittance optical window 1. The high-transmittance optical window 1 and the tracer particle loading port 4 are located upstream of the blade tip gap flow field measurement area inside the casing. The laser sheet light source 7 emits laser light to directly irradiate the blade tip gap flow field measurement area. The tracer particle generating module is connected to the tracer particle loading port 4 through a conduit. Under the control of the tracer particle automatic loading control module, tracer particles with a certain flow rate are generated. The tracer particles are uniformly added to the blade tip gap flow field measurement area through the tracer particle loading port 4. The tracer particle image recording camera 8 is located outside the casing and acquires images of the tracer particle activity in the blade tip gap flow field measurement area inside the casing through the high-transmittance optical window 1.

[0030] like Figure 2 As shown, the tracer particle loading port 4 is located between the rotating blade 2 and the stationary blade 3. Along the blade arrangement direction, there are three connection ports 403 for connecting to the output conduit of the tracer particle generating module. Figure 3The schematic diagram of the tracer particle loading port shows that the high-transmittance optical window 1 embedded in the casing has a certain thickness. The inner wall 101 of the high-transmittance optical window 1 is flush with the inner wall of the casing. The space between the inner wall of the casing and the tip of the rotating blade 2 is narrow. In order to release tracer particles into this gap, three connection ports 403 are respectively connected to the output conduit of the tracer particle generating module. The tracer particles enter the tracer particle loading port 4 through the straight hole 404 in the connection port 403, and then flow into the inclined rectangular slit 405 for mixing before being sent into the casing. The outlet of the rectangular slit 405 of the tracer particle loading port 4 forms an acute angle 401 with the casing wall. The tracer particle generating module includes a regulated gas source 501, a gas source pressure gauge 502, a tracer particle flow meter 503, and an ultrasonic tracer particle generator 504. The tracer particle automatic loading control module includes a controller 601, a photodetector 602, a tracer particle loading electric valve 603, and a pipeline purging control electric valve 604.

[0031] To achieve efficient loading of tracer particles, the tracer particle loading port 4 is located upstream of the flow field measurement area at the blade tip gap. The line connecting the center of the tracer particle loading port 4 and the center of the measurement field of view makes an angle of 45° with the axial direction. The output port of the tracer particle loading port 4 is arranged in a rectangular slit 405 with a slit width of 3 mm. The wide side of the slit corresponds to the circumferential direction of the casing, and the narrow side corresponds to the axial direction of the casing.

[0032] like Figure 3 , 4 As shown, to achieve uniform loading of tracer particles and reduce interference with the flow field, the tracer particle loading port 4 inlet 403 is distributed with three branches to ensure that the tracer particles enter the rectangular slit 405 uniformly. The outlet of the rectangular slit 405 forms an acute angle with the casing wall, with an angle range of 40°±5°, and the outlet of the rectangular slit 405 has a 4° expansion angle. To ensure uniform tracer particle distribution in the measurement area, the tracer particle loading port 4 inlet 403 is designed with multiple branches, and the slit serves to equalize the flow. The acute angle between the outlet of the rectangular slit 405 and the inner wall of the casing reduces the radial velocity component of the tracer particles and increases the axial velocity component, allowing the tracer particles to flow close to the casing wall and more easily enter the blade tip clearance 201 region. At the same time, this results in a smaller velocity component of the tracer particles perpendicular to the mainstream direction and a larger velocity component along the mainstream direction, making it easier to reach the mainstream velocity and reducing the measurement deviation caused by the inconsistency between the tracer particle velocity and the airflow velocity.

[0033] To facilitate cleaning of the optical window 1, the ultrasonic tracer particle generator 504 in the tracer particle generation module generates liquid mist tracer particles. The size and quantity of the tracer particles can be adjusted by the ultrasonic frequency and power. Furthermore, pure water is used as the working medium for the ultrasonic tracer particle generator 504, and the generated tracer particles are water mist, which can be easily evaporated by compressed air purging.

[0034] In order to carry the tracer particles generated by the ultrasonic tracer particle generator 504 to the tracer particle loading port 4, the tracer particles generated by the ultrasonic tracer particle generator 504 are carried into the tracer particle loading port 4 through the regulated gas source 501.

[0035] In order to adjust the concentration of tracer particles according to different test conditions, the controller 601 in the tracer particle automatic loading control module controls the concentration of tracer particles by adjusting the opening of the tracer particle loading electric valve 603 and the power of the ultrasonic tracer particle generator 504, and calculates the velocity of the tracer particles at the rectangular slit outlet 405 of the tracer particle loading port 4 by the tracer particle flow meter 503.

[0036] To achieve self-cleaning of the optical window 1, a photodetector 602 monitors whether a liquid film forms at the outlet 405 of the tracer particle loading port 4. If a liquid film forms, the laser sheet light source 7 and camera 8 are turned off, the ultrasonic tracer particle generator 504 is turned off, the pipeline purging control electric valve 604 is turned on, and the pressure stabilizing gas source 501 outputs gas to purge the pipeline. After the pipeline is cleaned, the ultrasonic tracer particle generator 504 is turned on to start the test.

[0037] To achieve automatic monitoring and cleaning of optical window contamination, the tracer particle automatic loading control module can be automatically controlled by a PLC. Since the impeller speed can reach 3000 rev / min during related experiments, and to ensure experimental safety, no personnel can operate the equipment on-site; therefore, the relevant controls are implemented using remote PLC control.

[0038] This embodiment of a gas turbine compressor blade tip clearance flow field tracer particle loading method is based on the aforementioned gas turbine compressor blade tip clearance flow field tracer particle loading system, and includes the following steps:

[0039] 1) The test equipment (gas turbine compressor) has reached the test operating conditions and is operating stably;

[0040] 2) Activate the tracer particle generation module to load tracer particles;

[0041] 3) A liquid film was detected forming at the outlet of the tracer particle loading port;

[0042] 4) If a liquid film is present, stop the laser output and camera recording, turn off the ultrasonic tracer particle generator, and open the pipeline purging control electric valve.

[0043] 5) After the liquid film in the optical window and tubing has been cleaned, the tracer particles will be loaded again.

[0044] 6) Adjust the amount of tracer particles loaded based on the recording results;

[0045] 7) The test is completed after multiple cycles;

[0046] 8) After the test, the pipeline was purged.

[0047] In order to achieve automatic monitoring and cleaning of optical window contamination, step 3) uses a photodetector to monitor whether a liquid film is formed at the tracer particle loading port outlet.

[0048] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A tracer particle injection system for a gas turbine engine compressor tip clearance flow field, the rotating blades and the stationary vanes being disposed in a cylindrical casing, characterized by, A high-transmittance optical window is embedded in the sealed opening of the casing, with its inner wall flush with the casing's inner wall. A tracer particle loading port is located on one side of the high-transmittance optical window. The high-transmittance optical window and the tracer particle loading port are situated upstream of the blade tip clearance flow field measurement area within the casing. A laser sheet light source emits laser light that directly illuminates the blade tip clearance flow field measurement area. A tracer particle generation module is connected to the tracer particle loading port via a conduit, generating tracer particles at a specific velocity under the control of an automatic tracer particle loading control module. These tracer particles are uniformly added to the blade tip clearance flow field measurement area through the tracer particle loading port. A tracer particle image recording camera is located outside the casing, recording the image of the blade tip clearance flow field within the casing through the high-transmittance optical window. Image acquisition is performed on the activity of tracer particles in the flow field measurement area. The tracer particle loading port is located between the rotating blade and the stationary blade. There are three connection ports along the blade arrangement direction on the tracer particle loading port. The three connection ports are used to connect with the output port conduit of the tracer particle generating module. The tracer particles enter through the straight holes in the three connection ports, and then flow into the inclined rectangular slit in the tracer particle loading port for mixing before being sent into the casing. The rectangular slit in the tracer particle loading port is 3mm wide. The wide side of the slit corresponds to the circumference of the casing, and the narrow side corresponds to the axial direction of the casing. The outlet of the rectangular slit forms an acute angle with the inner wall of the casing, so that the tracer particles flow along the casing wall and enter the flow field measurement area of ​​the blade tip gap.

2. The gas turbine compressor blade tip clearance flow field tracer particle loading system according to claim 1, characterized in that, The rectangular slit outlet forms an acute angle with the inner wall of the casing, with the acute angle ranging from 40°±5°, and the rectangular slit outlet has a 4° expansion angle.

3. The tracer particle injection system for turbine blade tip clearance flow field of claim 1 or 2, wherein, The tracer particle generation module includes a pressure-stabilized gas source, a tracer particle flow meter, and an ultrasonic tracer particle generator. The tracer particles generated by the ultrasonic tracer particle generator are carried into the tracer particle loading port by the pressure-stabilized gas source. The tracer particle flow meter calculates the velocity of the tracer particles at the rectangular slit outlet in the tracer particle loading port.

4. The gas turbine engine compressor tip clearance flow field tracer particle injection system according to Claim 3, wherein, The ultrasonic tracer particle generator uses pure water as its working medium to generate liquid mist tracer particles. The size and number of tracer particles are adjusted by the ultrasonic frequency and power.

5. The gas turbine engine compressor tip clearance flow field tracer particle injection system according to Claim 4, wherein, The automatic tracking particle loading control module includes a controller, a photodetector, a tracking particle loading electric valve, and a pipeline purging control electric valve. The tracking particle loading electric valve is connected between the regulated gas source and the ultrasonic tracking particle generator. The controller controls the concentration of tracking particles by adjusting the opening of the tracking particle loading electric valve and the power of the ultrasonic tracking particle generator. The pipeline purging control electric valve is connected to the output pipeline of the regulated gas source. The photodetector monitors whether a liquid film is formed at the rectangular slit outlet of the tracking particle loading port.

6. A method for loading tracer particles into the flow field of the blade tip clearance of a gas turbine compressor, characterized in that, Includes the following steps: 1) Establish a gas turbine compressor blade tip clearance flow field tracer particle loading system as described in any one of claims 1 to 5; 2) The test equipment has reached the test conditions and is operating stably; 3) Activate the tracer particle generation module to load tracer particles; 4) A liquid film was detected forming at the outlet of the tracer particle loading port; 5) If a liquid film is present, stop the laser output and camera recording, turn off the ultrasonic tracer particle generator, and open the pipeline purging control electric valve; 6) After the high-transmission optical window and the liquid film in the pipeline are blown clean, start loading the tracer particles again; 7) Adjust the amount of tracer particles loaded according to the recording effect; 8) Complete the test after multiple cycles; 9) Blow down the pipeline after the test is completed.

Images