A cold state overspeed pre-rotation test method for examining the structural integrity of a gas turbine wheel disc

Abstract

The application aims to provide a cold state overspeed pre-rotation test method for gas turbine wheel disc structure integrity examination, belonging to the field of gas turbine, comprising the following steps: sequentially performing rotor assembly and dynamic balance, rotor installation, normal temperature test rotation, temperature field calibration, cold state pre-rotation test, finally performing test result effectiveness analysis to determine whether the wheel disc meets the structure integrity, during which dynamic balance standard judgment, installation standard judgment, vibration amplitude standard judgment and temperature field standard judgment are performed respectively. The application can detect internal defects without damaging the wheel disc, effectively improving the reliability of the wheel disc.

Description

TECHNICAL FIELD

[0001] The present application relates to a gas turbine test method, in particular, a wheel disc integrity test method. BACKGROUND

[0002] The ship and industrial gas turbine are developing towards higher power and larger size. In order to make the gas turbine have enough strength, the rotating part of the wheel disc is often designed to be thick and heavy. The thick and heavy wheel disc will have internal defects (such as segregation and hydrogen and sulfur-containing brittle zone), which cannot be detected by ordinary ultrasonic detection. When the wheel disc works at extremely cold temperature, the material will become brittle, and the crack defect may expand to the critical value at the working speed to cause the wheel disc to break. The destruction energy of the wheel disc at high speed is huge, which will have disastrous consequences on the ship, the plant and the personal safety. Therefore, how to design a method to check the structural integrity of the wheel disc is particularly important.

[0003] The cold-state overspeed pre-stress test technology of the wheel disc can expand the crack defect in advance during the overspeed process to make the wheel disc with large defect break; if the defect does not cause damage, the opening generated can be detected by subsequent non-destructive detection, so as to avoid the damage that may occur during use. SUMMARY

[0004] The purpose of the present application is to provide a cold-state overspeed pre-rotation test method for checking the structural integrity of the gas turbine wheel disc, which can detect the internal defects without damaging the wheel disc and effectively improve the reliability of the wheel disc.

[0005] The purpose of the present application is achieved in the following way:

[0006] The cold-state overspeed pre-rotation test method for checking the structural integrity of the gas turbine wheel disc according to the present application is characterized by comprising the following steps:

[0007] (1) performing rotor assembly and dynamic balancing;

[0008] (2) performing dynamic balancing standard judgment, if the unbalance requirement is met, step (3) is performed, otherwise, step (1) is repeated to perform re-dynamic balancing;

[0009] (3) performing rotor installation;

[0010] (4) performing installation standard judgment, if the round run-out requirement is met, step (5) is performed, otherwise, step (3) is performed;

[0011] (5) performing normal temperature trial rotation;

[0012] (6) performing vibration amplitude standard judgment, if the vibration standard is met, step (7) is performed, otherwise, step (1) is repeated to perform re-dynamic balancing;

[0013] (7) temperature field calibration is performed;

[0014] (8) temperature field calibration is performed, if the temperature requirement range is met, step (9) is performed, otherwise, step (7) is repeated;

[0015] (9) cold state pre-rotation test is performed;

[0016] (10) test result effectiveness analysis is performed to determine whether the wheel disc meets the structural integrity.

[0017] The present application can also include:

[0018] 1. After the rotor assembly in step (1) is completed, the diameter of the disc core hole is measured: at least three different positions in the disc core hole are measured along the axial direction, two diameter measurements are performed at each position at 90° to each other, and the positions must be marked on the wheel disc, the average of the measured multiple sizes is recorded as Dpp, and the temperature at the time of measurement is recorded as Ts.

[0019] 2. The dynamic balance standard in step (2) is that the residual unbalance after dynamic balancing should be less than 100 g·mm.

[0020] 3. The installation standard in step (4) is that the circular runout of any circular surface of the test piece after installation is less than 0.1 mm.

[0021] 4. The vibration amplitude standard in step (6) is that the vibration amplitude of the test piece is less than 70 μm when the test piece reaches the maximum steady state speed.

[0022] 5. The temperature standard in step (8) is that the absolute value of the difference between the calibration temperature and the required temperature is less than 10℃.

[0023] 6. The calculation method of the cold state pre-rotation test speed N C in step (9) is:

[0024]

[0025] Wherein K is a coefficient related to the structure of the wheel disc and the material performance.

[0026] 7. The cold state pre-rotation test in step (9) requires the following: the wheel disc is kept at the specified temperature for at least 3 hours before the test, and the wheel disc rotates at a speed of N C for at least 1 minute;

[0027] After the test is completed, the wheel disc is cooled down, and when the wheel disc is thermally stable, the diameter of the disc core hole of the wheel disc is measured at the same positions and in the same way as in step (1), and the average is recorded as Duse, and the temperature at the time of measurement is recorded as Te.

[0028] 8. Step (10) Test result validity analysis: After the rotation test, non-destructive testing is performed on all surfaces of the wheel. If no cracks are found, the wheel meets the structural integrity check. If cracks are found, the wheel is scrapped.

[0029] The advantage of this invention is that it can detect internal defects without damaging the wheel, effectively improving the reliability of the wheel. Attached Figure Description

[0030] Figure 1 This is a flowchart of the present invention;

[0031] Figure 2 This is a schematic diagram of a gas turbine disk. Detailed Implementation

[0032] The invention will now be described in more detail with reference to the accompanying drawings:

[0033] Combination Figures 1-2 The present invention provides a cold-state overspeed pre-rotation test method for assessing the structural integrity of a gas turbine disk, the specific steps of which are as follows:

[0034] Step 1: Perform rotor assembly and dynamic balancing, including assembling and dynamically balancing the test piece with the transfer plate, simulated blades and other test components.

[0035] After the rotor is assembled, it needs to be... Figure 2 The diameter of the disc center hole is measured by measuring at least three different locations along the axial direction. At each location, two diameter measurements must be taken at mutually perpendicular 90° angles, and these locations must be marked on the disc. The average of the measured dimensions is recorded as Dpp; the temperature during the measurement is also recorded as Ts.

[0036] Step 2: Perform dynamic balance standard judgment. If the unbalance requirement is met, proceed to Step 3. If not, repeat Step 1 to perform dynamic balance again.

[0037] The standard for dynamic balancing is that the residual imbalance after dynamic balancing should be less than 100 g·mm.

[0038] Step 3: Install the rotor by connecting the rotor test piece to the rotating tester via an intermediate connecting fixture.

[0039] Step 4: Perform an installation standard check. If the circular runout requirement is met, proceed to Step 5; otherwise, proceed to Step 3.

[0040] The installation standard is that the circular runout of any circumferential surface of the test piece after installation should be less than 0.1 mm.

[0041] Step 5: Conduct a trial run at room temperature.

[0042] Step 6: Perform vibration amplitude standard judgment, if the vibration standard is met, then proceed to Step 7, otherwise repeat Step 1 to re-balance.

[0043] The vibration amplitude standard is that the vibration amplitude of the test piece is less than 70 μm when the test piece reaches the maximum steady speed.

[0044] Step 7: Perform temperature field calibration.

[0045] Step 8: Perform temperature field standard judgment, if the temperature requirement range is met, then proceed to Step 9, otherwise repeat Step 7.

[0046] The temperature standard is that the absolute value of the difference between the calibration temperature and the required temperature is less than 10℃.

[0047] Step 9: Perform cold-state pre-rotation test, the key parameters of the test include cold-state pre-rotation test speed, holding time before cold-state pre-rotation test, holding time of cold-state pre-rotation test speed, and cold-state pre-rotation test temperature. Before the temperature reaches the required test temperature, low-speed rotation is performed at a speed of 100-200 r / min to ensure uniform cooling of the wheel disc.

[0048] The cold-state pre-rotation test speed N C is calculated as follows:

[0049]

[0050] where K is a coefficient related to the structure and material properties of the wheel disc.

[0051] In the formula:

[0052] - Yield limit of 0.2% at 20 degrees Celsius, in units of MPa.

[0053] The mechanical properties at 20℃ temperature are obtained using a test piece collected from the area close to the disc core hole.

[0054] The cold-state pre-rotation test requires the following: the holding time before the cold-state pre-rotation test must be at least 3 hours to perform the test, and the holding time of the cold-state pre-rotation test speed must be at least 1 minute.

[0055] After the test is completed, the wheel disc is cooled, and when the wheel disc is thermally stable, the temperature is measured, the disc core hole diameter of the wheel disc is measured at the same position and in the same way as in Step 1, the average value is recorded as Duse, and the temperature at which the size is measured is recorded as Te.

[0056] Step 10: Perform test result validity analysis. Non-destructive testing is performed on all surfaces of the wheel disc, if no cracks are found, the wheel disc meets the structural integrity check, if cracks are found, the wheel disc is scrapped.

Claims

1. A cold spin test method for gas turbine disk structural integrity evaluation, characterized in that: The method comprises the following steps: (1) rotor assembly and dynamic balancing; (2) dynamic balancing standard judgment, if the unbalance meets the requirement, step (3) is performed, otherwise, step (1) is repeated for re-dynamic balancing; (3) rotor installation; (4) installation standard judgment, if the round run-out meets the requirement, step (5) is performed, otherwise, step (3) is performed; (5) normal temperature trial rotation; (6) vibration amplitude standard judgment, if the vibration meets the standard, step (7) is performed, otherwise, step (1) is repeated for re-dynamic balancing; (7) temperature field calibration; (8) temperature field standard judgment, if the temperature meets the requirement, step (9) is performed, otherwise, step (7) is repeated; (9) cold state pre-rotation test; the key parameters of the test include cold state pre-rotation test speed, holding time before the cold state pre-rotation test, holding time of the cold state pre-rotation test speed and cold state pre-rotation test temperature; before the temperature reaches the required temperature, low-speed rotation is performed at a speed of 100-200 r / min to ensure uniform cooling of the wheel disc; The cold pre-rotation test speed N C The calculation method is: where K is a coefficient related to the wheel disc structure and material properties; and - a 0.2% yield strength at 20 degrees Celsius in MPa; mechanical properties of the sample collected from the area close to the disc hole at a temperature of 20 DEG C are used; the cold state pre-rotation test requires that the holding time before the cold state pre-rotation test is at least 3 h, and the holding time of the cold state pre-rotation test speed is at least 1 min; (10) test result effectiveness analysis to determine whether the wheel disc meets the structural integrity.

2. A cold spin test method for evaluating the structural integrity of a gas turbine disk according to claim 1, characterized in that: After the rotor assembly in step (1), the diameter of the disc hole is measured: the diameter is measured at not less than three different positions along the axial direction of the disc hole, the diameter is measured twice at each position at 90 DEG to each other, and the positions are marked on the wheel disc, the average of the measured sizes is recorded as Dpp, and the temperature when the size is measured is recorded as Ts.

3. A cold spin test method for evaluating the structural integrity of a gas turbine disk according to claim 1, characterized in that: The dynamic balancing standard in step (2) is that the residual unbalance after dynamic balancing should be less than 100 g·mm.

4. A cold spin test method for evaluating the structural integrity of a gas turbine disk according to claim 1, characterized in that: The installation standard in step (4) is that the round run-out of any circumferential surface of the test piece after installation is less than 0.1 mm.

5. A cold spin test method for evaluating the structural integrity of a gas turbine disk according to claim 1, characterized in that: The vibration amplitude standard in step (6) is that when the test piece reaches the maximum steady speed, the vibration amplitude is less than 70 μm.

6. A cold spin test method for evaluating the structural integrity of a gas turbine disk according to claim 1, characterized in that: The temperature standard in step (8) is that the absolute value of the difference between the calibration temperature and the required temperature is less than 10 DEG C.

7. A cold spin test method for evaluating the structural integrity of a gas turbine disk according to claim 1, characterized in that: After the test in step (9), the wheel disc is cooled, and when the wheel disc is thermally stable, the diameter of the disc hole of the wheel disc is measured at the same positions and in the same way as in step (1), the average is recorded as Duse, and the temperature when the size is measured is recorded as Te.

8. A cold spin test method for evaluating the structural integrity of a gas turbine disk according to claim 1, characterized in that: The test result effectiveness analysis in step (10) is that after the rotation test, all surfaces of the wheel disc are detected by non-destructive testing, if no cracks are found, the wheel disc meets the structural integrity check, and if cracks are found, the wheel disc is scrapped.

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