Dynamic balancing method for vibration problem of gas turbine unit shafting misalignment

Abstract

The present application relates to the field of gas turbine technology, and more particularly to a dynamic balancing method for the misalignment vibration problem of a gas turbine unit shaft system, which comprises the following steps in sequence: step A, implementing a first dynamic balancing weight scheme on a first weight plane of the gas turbine rotor; and step B, implementing a second dynamic balancing weight scheme on a second weight plane of the gas turbine rotor, wherein the weight angle of the second dynamic balancing weight scheme is 180 degrees different from the weight angle of the first dynamic balancing weight scheme. The dynamic balancing method for the misalignment vibration problem of the gas turbine unit shaft system according to the present application selects two weight planes to implement opposite weight, and the generated weight bending moment can balance the additional bending moment, so that the vibration condition of the unit is obviously improved. Different from the traditional influence coefficient method, the dynamic balancing method according to the present application directly attacks the essence of the vibration problem, reduces the number of starting machines and the resulting psychological pressure, saves considerable test cost, and has good application effect and promotional value.

Description

Technical Field

[0001] This invention relates to the field of gas turbine technology, and in particular to a dynamic balancing method for the problem of misalignment and vibration in the shaft system of a gas turbine unit. Background Technology

[0002] The two main factors affecting gas turbine vibration are unbalanced mass and shaft misalignment. For large gas turbine generator sets, both the gas turbine and generator undergo high-precision dynamic balancing at the manufacturing plant. For example, the F-class gas turbine has a dynamic balancing accuracy of G2.5 for the entire tie rod rotor in the workshop, with a rated speed of 3000 rpm and a residual unbalance of e. per =8μm, the vibration is very small. However, during the installation of new machines, the vibration performance after starting, maintaining speed and being loaded varies when the gas turbine rotor, intermediate shaft and generator rotor are connected into a shaft system. Some items have very good vibration levels, with the measured values ​​of shaft vibration and bearing vibration both in Zone A of the international standard, requiring no adjustment; but some items have very poor vibration performance, exceeding the alarm value at one point, and certain solutions must be taken.

[0003] As mentioned above, the inherent imbalance of the rotor structure in both gas turbines and generators is sufficiently small. The main cause of vibration problems on-site is shaft misalignment. Factors influencing this misalignment may include rotor downtime, the installer's feel during measurement, measurement errors, environmental factors, and so on. Even a well-aligned shaft system can experience foundation settlement and rotor bending after prolonged unit operation, ultimately manifesting as misalignment failure. In fact, a smooth and continuous shaft curve is only an ideal state; the degree of misalignment varies only in severity.

[0004] Shaft misalignment can be categorized into parallel misalignment and angular misalignment. The F-class gas turbine shaft system uses rigid couplings with flanged joints, so parallel misalignment has a relatively smaller impact, while angular misalignment has a larger impact. When angular misalignment exists, the two rotors are bolted together, causing an additional bending moment in the coupling at that point. During unit operation, due to the influence of this additional bending moment, vibration will manifest as a first harmonic, ultimately leading to vibration problems.

[0005] Currently, there are two main methods for resolving misalignment: on-site realignment of the shaft system and dynamic balancing. The former incurs significant time costs; for large F-type units, shaft realignment typically takes 7-10 days, during which time the unit is inoperable, resulting in substantial economic losses for the owner. Unless the problem is particularly severe, owners generally avoid shaft system adjustments during production and instead include this work in the unit's maintenance schedule. Therefore, the latter method, dynamic balancing, has become the preferred choice for improving such vibration issues, and experience shows it to be quite effective.

[0006] The traditional approach to dynamic balancing involves conducting trial weighting tests on multiple weighting planes to obtain the influence coefficients of each plane. Then, a multi-plane, multi-measuring-point balancing calculation method is used to develop a dynamic balancing scheme. This method solves vibration problems mathematically, and for mass imbalance vibration problems, good balancing results are usually achieved in 2-3 cycles. However, for shaft misalignment vibration problems, the oil film at the bearing exhibits nonlinear dynamic characteristics due to the additional bending moment. This results in different influence coefficients calculated after each weighting, making it impossible to accurately determine the weighting angle. Furthermore, during dynamic balancing, one end may be pressed down while the other tilts up, further increasing the difficulty of dynamic balancing. In such cases, dynamic balancing experts often have to repeatedly start the machine to observe the effects, enduring significant psychological pressure, and may even fail to achieve balance. Summary of the Invention

[0007] In view of the above-mentioned deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a dynamic balancing method for the vibration problem of misalignment of the shaft system of a gas turbine unit, which can effectively improve the vibration of the unit.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] This invention provides a dynamic balancing method for the vibration problem of misalignment in the shaft system of a gas turbine unit, comprising the following steps: Step A, implementing a first dynamic balancing weighting scheme on a first weighting plane on the gas turbine rotor; Step B, implementing a second dynamic balancing weighting scheme on a second weighting plane on the gas turbine rotor, wherein the weighting angle of the second dynamic balancing weighting scheme differs from that of the first dynamic balancing weighting scheme by 180°.

[0010] Preferably, the relationship between the weight added in the second dynamic balancing scheme and the weight added in the first dynamic balancing scheme satisfies: M F =M M ×R M / R F , of which M F and R F These represent the added weight and radius of the second dynamic balancing scheme, M.M and R M These represent the added weight and radius of the first dynamic balancing scheme, respectively.

[0011] Preferably, the first dynamic balancing weighting scheme is implemented, and the machine is started once to measure the vibration data; then the second dynamic balancing weighting scheme is implemented, and the machine is started once to measure the vibration data.

[0012] Preferably, the first weighting plane is located in the middle of the gas turbine rotor, and the second weighting plane is located on the gas turbine rotor near the gas turbine compressor side bearing.

[0013] Preferably, in step A, a weighting test is conducted on the first weighting plane to obtain the influence coefficient of the first weighting plane, and the corrected weighting weight and corrected weighting angle of the first weighting plane are calculated. The corrected weighting weight and corrected weighting angle are respectively used as the weighting weight and weighting angle of the first dynamic balancing weighting scheme.

[0014] Preferably, before step A, the following steps are performed sequentially: Step S1: Collect vibration data of the gas turbine unit; Step S2: Perform vibration fault characteristic analysis of the gas turbine unit shaft misalignment, and proceed to the next step S3 when the gas turbine unit vibration data matches the vibration fault characteristics; Step S3: Determine the degree of misalignment of the gas turbine unit shaft system. If the bearing bush metal temperature change trend is abnormal, it is determined to be severe misalignment; otherwise, it is determined to be mild to moderate misalignment; when it is determined to be mild to moderate misalignment, proceed to steps A and B; when it is determined to be severe misalignment, realign the gas turbine unit shaft system.

[0015] Preferably, in step S2, the vibration fault characteristics of the gas turbine unit shaft misalignment include: Characteristic 1: During the start-up process of the gas turbine unit's speed increasing from the turning gear speed to the first critical speed and then to the rated speed, at the first critical speed, the shaft vibration of the gas turbine compressor-side bearing or the generator gas turbine-side bearing exceeds the set shaft vibration alarm value; Characteristic 2: During the start-up process, at the rated speed, the shaft vibration of at least two of the gas turbine turbine-side bearing, the gas turbine compressor-side bearing, and the generator gas turbine-side bearing is close to or exceeds the set shaft vibration alarm value; Characteristic 3: During the start-up process, at the rated speed, the vibration spectrum analysis results of the gas turbine unit show that the power frequency is dominant; Characteristic 4: During the start-up process, at the rated speed, the X-direction shaft vibration value and the Y-direction shaft vibration value of the gas turbine turbine-side bearing are out of phase or nearly out of phase; Characteristic 5: After the gas turbine unit is under load, the vibration of the gas turbine unit is correlated with the load change; When the gas turbine unit vibration data meets at least three of characteristics one to five, the gas turbine unit vibration data is considered to meet the vibration fault characteristics.

[0016] Preferably, in step S3, mild to moderate misalignment means that under rated speed or load conditions, the bearing vibration of the gas turbine compressor side bearing or the gas turbine turbine side bearing is within the range of 4.5 mm / s to 9.3 mm / s, or the shaft vibration of the gas turbine compressor side bearing or the gas turbine turbine side bearing exceeds the set shaft vibration alarm value, and the bearing bearing metal temperature change trend is not abnormal.

[0017] Compared with the prior art, the present invention has significant progress:

[0018] The essence of vibration problems caused by misalignment in gas turbine generator sets lies in the presence of additional bending moments at the couplings. The dynamic balancing method for this invention addresses this vibration problem by using two opposing weighting planes (with weighting angles differing by 180°). The resulting additional bending moments balance the additional bending moments, significantly improving the generator set's vibration. Unlike the traditional influence coefficient method, this dynamic balancing method directly addresses the root cause of the vibration problem, reducing the number of start-ups and the associated psychological stress, saving considerable testing costs, demonstrating excellent application results, and possessing significant potential for wider application. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the dynamic balancing method for addressing the misalignment and vibration problem of the gas turbine unit shaft system according to an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the shafting system of the gas turbine unit in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the gas turbine shaft vibration measurement system in an embodiment of the present invention.

[0022] The reference numerals in the attached figures are explained as follows:

[0023] 10 Gas turbine 3 Generator gas turbine side bearing

[0024] 20 Intermediate Shaft 4 Generator Excitation Side Bearing

[0025] 30 Generators 5 Eddy Current Sensors

[0026] 1. Gas turbine turbine-side bearing P1, first weighting plane

[0027] 2. Gas turbine compressor side bearing P2, second weighting plane Detailed Implementation

[0028] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0029] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0031] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0032] like Figures 1 to 3 The figure shows an embodiment of the dynamic balancing method for the misalignment vibration problem of the gas turbine unit shaft system according to the present invention. See also Figure 2 The gas turbine unit shaft system includes a gas turbine 10, an intermediate shaft 20, a generator 30, and an exciter (not shown in the figure). The gas turbine 10 includes a turbine and a compressor connected together. The intermediate shaft 20 connects the compressor of the gas turbine 10 and the generator 30. The gas turbine 10 is provided with a turbine-side bearing 1 and a compressor-side bearing 2 at both ends. The generator 30 is provided with a gas turbine-side bearing 3 and an exciter-side bearing 4 at both ends.

[0033] See Figure 1 The dynamic balancing method for the misalignment vibration problem of the gas turbine unit shaft system in this embodiment includes the following steps in sequence.

[0034] Step A: Implement the first dynamic balancing weighting scheme on the first weighting plane P1 of the gas turbine 10 rotor. The first weighting plane P1 is preferably located in the middle of the gas turbine 10 rotor, specifically between the turbine-side bearing 1 and the compressor-side bearing 2. Preferably, in Step A, a weighting test is conducted on the first weighting plane P1 to obtain its influence coefficient. The corrected weighting weight and corrected weighting angle for the first weighting plane P1 are calculated. These corrected weighting weight and angle are weights and angles that can reduce over-critical vibration on the first weighting plane P1. These corrected weighting weight and angle are used as the weighting weight and angle for the first dynamic balancing weighting scheme, thus completing the formulation of the first dynamic balancing weighting scheme at the first weighting plane P1. Preferably, the first dynamic balancing weighting scheme is implemented, and the turbine is started once to measure vibration data.

[0035] Step B: Implement a second dynamic balancing weighting scheme on the second weighting plane P2 on the gas turbine 10 rotor. The weighting angle of the second dynamic balancing weighting scheme differs from that of the first dynamic balancing weighting scheme by 180°, that is, the weight is increased in the opposite direction to that of the first weighting plane P1 compared to the second weighting plane P2. The second weighting plane P2 is preferably located on the gas turbine 10 rotor near the compressor-side bearing 2. Preferably, the relationship between the weight added in the second dynamic balancing weighting scheme and the weight added in the first dynamic balancing weighting scheme satisfies: M F =M M ×R M / R F , of which M F For the weight increase in the second dynamic balancing scheme, R F M is the radius of gravity for the second dynamic balancing weighting scheme. M For the weight increase in the first dynamic balancing scheme, R M R represents the radius of the first dynamic balancing weighting scheme. F and R M The values ​​can be obtained from the design drawings of the gas turbine 10. Based on the weight added in the first dynamic balancing scheme, the weight added in the second dynamic balancing scheme is calculated and determined, thus completing the preparation of the second dynamic balancing scheme at the second weighting plane P2. Preferably, the second dynamic balancing scheme is implemented, and the turbine is started once to measure vibration data. Based on the vibration data measured after the two weightings, the dynamic balancing effect is observed and evaluated.

[0036] The essence of vibration problems caused by misalignment in gas turbine generator sets lies in the presence of additional bending moments at the couplings. The dynamic balancing method for this problem in this embodiment employs two opposing weighting planes (with weighting angles differing by 180°). The resulting additional bending moments balance out the additional bending moments, significantly improving the unit's vibration. Unlike the traditional influence coefficient method, this dynamic balancing method directly addresses the root cause of the vibration problem, reducing the number of start-ups and the associated psychological stress, saving considerable testing costs. Its application is effective and has significant potential for wider adoption.

[0037] The dynamic balancing method for the misalignment vibration problem of the gas turbine unit shaft system in this embodiment can significantly improve the vibration of the gas turbine unit through the two weighting processes described above. In practical applications, if individual shaft vibrations require further optimization, a fine-tuning scheme can be developed using the influence coefficients of the two weighting planes calculated in steps A and B above.

[0038] See Figure 1 Preferably, the dynamic balancing method for the misalignment vibration problem of the gas turbine unit shaft system in this embodiment performs the following steps in sequence before step A.

[0039] Step S1: Collect vibration data of the gas turbine unit. Vibration data can be collected through offline equipment or the Rotating Machinery Diagnostic Monitoring and Management System (TDM system) during the start-up, speed stabilization, and load-bearing processes of the gas turbine unit. This step should ensure that the sensor sensitivity coefficients are set correctly and that the collected vibration data is accurate and valid. The vibration data should include the passband value, power frequency value, and half-harmonic and second-harmonic components at the corresponding speed.

[0040] Step S2: Perform vibration fault characteristic analysis on the misalignment of the gas turbine unit shaft system. When the vibration data of the gas turbine unit matches the vibration fault characteristics, proceed to the next step S3. In this embodiment, preferably, the vibration fault characteristics of the misalignment of the gas turbine unit shaft system include the following characteristics.

[0041] Feature 1: During the startup process of the gas turbine unit, when the speed increases from the turning gear speed to the first critical speed and then to the rated speed, at the first critical speed, the shaft vibration of the gas turbine compressor side bearing 2 or the generator gas turbine side bearing 3 exceeds the set shaft vibration alarm value.

[0042] Feature 2: During startup, at rated speed, the shaft vibration of at least two of the following components—the turbine-side bearing 1, the compressor-side bearing 2, and the generator-gas turbine-side bearing 3—approaches or exceeds the set shaft vibration alarm value, meaning that the shaft vibration of at least two of these components is significantly excessive.

[0043] Feature 3: During startup, at rated speed, the vibration spectrum analysis of the gas turbine unit shows that the power frequency is dominant, and may contain a certain second harmonic component.

[0044] Feature 4: During startup, at rated speed, the X-axis vibration value and the Y-axis vibration value of the turbine-side bearing 1 of the gas turbine are out of phase or nearly out of phase, that is, the phase difference between the X-axis vibration value and the Y-axis vibration value of the turbine-side bearing 1 of the gas turbine is about 180°.

[0045] Feature 5: After the gas turbine unit is under load, the vibration of the gas turbine unit is correlated with the load change. In addition, a "seesaw" phenomenon can be observed in the historical vibration trend of the gas turbine side bearing 1 and the generator gas turbine side bearing 3.

[0046] When the vibration data of a gas turbine unit meets at least three of the above-mentioned characteristics one to five, the vibration data of the gas turbine unit is considered to meet the characteristics of a vibration fault.

[0047] Step S3: Determine the degree of misalignment of the gas turbine unit shaft system. If the temperature change trend of the bearing bush metal is abnormal, it is determined to be severe misalignment; otherwise, it is determined to be mild to moderate misalignment. When it is determined to be mild to moderate misalignment, proceed to steps A and B; when it is determined to be severe misalignment, realign the gas turbine unit shaft system.

[0048] In this embodiment, mild to moderate misalignment refers to the bearing vibration of the gas turbine compressor-side bearing 2 or the gas turbine-side bearing 1 being within the range of 4.5 mm / s to 9.3 mm / s under rated speed or load conditions, or the shaft vibration of the gas turbine compressor-side bearing 2 or the gas turbine-side bearing 1 exceeding the set shaft vibration alarm value, and the bearing metal temperature change trend is normal. At this time, the vibration is operating between zones A and B as described in Part 4 of the international vibration standard ISO 20816, but it does not meet the zone A standard requirements for newly installed units and requires optimization. Under this condition, the unit does not pose a safety risk. The amplitude and phase of the shaft vibration are basically stable at this time. After the gas turbine unit reaches a constant speed, the vibration may increase, but it will eventually reach a steady-state value. The vibration of the gas turbine unit is correlated with the load to a certain extent. When the misalignment of the gas turbine unit shaft system is determined to be mild to moderate, steps A and B of the above-mentioned dynamic balancing method for the vibration problem of misalignment of the gas turbine unit shaft system in this embodiment can be used to effectively improve the vibration of the unit by adding weight in opposite phases on two weighting planes.

[0049] An abnormal trend in the bearing metal temperature refers to a deviation from the normal trend, exhibiting unusually low temperatures or a gradual increase in temperature. This results in significant sway during low-speed cranking of the gas turbine unit, followed by substantial vibration after reaching a constant speed, with an increasing trend. This warrants attention to the risk of bearing instability and dynamic-static friction. In this case, the misalignment of the gas turbine unit shaft system is classified as severe misalignment. For severe misalignment, realigning the gas turbine unit shaft system is necessary. Therefore, steps A and B of the dynamic balancing method described in this embodiment for addressing the misalignment and vibration problem of the gas turbine unit shaft system are not applicable in this situation.

[0050] In a specific embodiment, taking a certain F-class split-shaft gas turbine unit as an example, the shaft system schematic diagram of the unit is as follows: Figure 2 As shown, combined with Figure 3 Each bearing in the unit's shaft system is equipped with an eddy current sensor 5 in both the X and Y directions. The eddy current sensors 5 in the X and Y directions are symmetrically arranged on the left and right sides of the vertical direction at a 45° angle to the vertical direction. Looking from the compressor of the gas turbine 10 towards the turbine, the rotor rotates counterclockwise, and the unit's turning speed is around 200 r / min.

[0051] During the initial installation phase of the new unit, the shaft vibrations of the gas turbine turbine-side bearing 1, the gas turbine compressor-side bearing 2, and the generator gas turbine-side bearing 3 were 72 ump, 95 ump, and 69 ump, respectively (p represents a single peak value). The set shaft vibration alarm value was 80 ump. It is evident that the shaft vibration levels of these three bearings are all relatively high. The raw vibration data collected using professional vibration analysis equipment is shown in Table 1 below. Vibration is expressed in the format of "amplitude ∠phase", with the unit of amplitude being umpp (pp represents a double peak value). 1X and 1Y represent the eddy current sensor 5 measuring points in the X and Y directions of the gas turbine turbine-side bearing 1, respectively; 2X and 2Y represent the eddy current sensor 5 measuring points in the X and Y directions of the gas turbine compressor-side bearing 2, respectively; 3X and 3Y represent the eddy current sensor 5 measuring points in the X and Y directions of the generator gas turbine-side bearing 3, respectively; 300 r / min is the unit's turning speed; and 3000 r / min is the unit's rated speed.

[0052] Table 1. Raw vibration data

[0053]

[0054] As shown in Table 1, the runout of each bearing in the gas turbine unit's shaft system is very small under low-speed turning conditions, indicating that the rotor is not bent. When the speed increases to the first critical speed, the 2Y measuring point of the gas turbine compressor-side bearing 2 becomes significantly larger, with the monitoring system displaying a value of 92 ump, triggering an alarm. When the speed increases to the rated speed, after the gas turbine unit reaches a constant speed of 3000 r / min, the shaft vibrations of the gas turbine-side bearing 1, the gas turbine compressor-side bearing 2, and the generator gas turbine-side bearing 3 are 64 ump, 87 ump, and 70 ump, respectively, indicating poor vibration performance. The phase deviation measured at the 1X and 1Y measuring points of the gas turbine-side bearing 1 is approximately 180°. Since there is no grid-connected load during the dynamic balancing test, the correlation between the gas turbine unit's vibration and the load cannot be evaluated. In addition, the temperature change trends of the bearing metal of the gas turbine-side bearing 1, the gas turbine compressor-side bearing 2, and the generator gas turbine-side bearing 3 were examined, and no abnormalities were found.

[0055] In the existing technology, during the commissioning phase, the equipment manufacturer and vibration professionals conducted nearly 10 dynamic balancing tests over a period of one year to address the vibration problem of the unit. During the weighting test, it was found that the calculated influence coefficients were different for each weighting. More challenging was the "seesaw" phenomenon between the shaft vibration of the turbine-side bearing 1 of the gas turbine and the shaft vibration of the generator-side bearing 3. Given the high initial vibration level, it was difficult to balance the shaft vibration levels of all three bearings, and the dynamic balancing work temporarily stalled.

[0056] The dynamic balancing method for addressing the misalignment vibration problem of the gas turbine unit shaft system, as described in this embodiment, achieves a significant improvement in the unit's vibration condition. Details are as follows.

[0057] The first step involves using step A of the dynamic balancing method for the misalignment vibration problem of the gas turbine unit shaft system in this embodiment to reduce the shaft vibration of the compressor side bearing 2 of the gas turbine at the first critical speed.

[0058] First, remove the balance blocks from all weighted planes. Then, perform a trial weighting and restart the machine on the first weighted plane P1 to obtain its influence coefficient. Calculate the correction scheme for the first weighted plane P1, i.e., the first dynamic balancing weighting scheme. After implementing the first dynamic balancing weighting scheme on the first weighted plane P1, the measured vibration data are shown in Table 2 below.

[0059] Table 2 Vibration data measured after the first increase in weight.

[0060]

[0061] The second step involves step B of the dynamic balancing method for the misalignment vibration problem of the gas turbine unit shaft system in this embodiment, which reduces the shaft vibration of the turbine-side bearing 1 of the gas turbine at rated speed.

[0062] Based on the weighting angle of the first step correction scheme, weight is added in the opposite phase (+180°) on the second weighting plane P2. The weighting weight is calculated according to the weighting weight of the first step correction scheme using formula M. F =M M ×R M / R F The calculation yielded the second dynamic balancing weighting scheme. After implementing the second dynamic balancing weighting scheme on the second weighting plane P2, the measured vibration data are shown in Table 3 below.

[0063] Table 3 Vibration data measured after the second increase in weight.

[0064]

[0065] By implementing the above two steps, the measured vibration data shows that the shaft vibration of the gas turbine side bearing 1, gas turbine compressor side bearing 2, and generator gas turbine side bearing 3 of the gas turbine unit shaft system has been significantly improved. After the gas turbine unit reaches a constant speed of 3000 r / min, the shaft vibrations of the gas turbine side bearing 1, gas turbine compressor side bearing 2, and generator gas turbine side bearing 3 are 47 ump, 49 ump, and 51 ump, respectively, all within the A zone of the vibration standard, indicating that the dynamic balancing work has been successfully completed.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A dynamic balancing method for misalignment vibration problems of a gas turbine unit shafting, characterized by, Comprise the following steps in sequence: Step A, implement a first dynamic balance weight scheme on a first weight plane of a gas turbine rotor; Step B, implement a second dynamic balance weight scheme on a second weight plane of the gas turbine rotor, the weight angle of the second dynamic balance weight scheme being 180° different from the weight angle of the first dynamic balance weight scheme; Before the step A, the following steps are sequentially performed: Step S1, collect gas turbine unit vibration data; Step S2, perform vibration fault feature analysis of gas turbine unit shafting misalignment, and when the gas turbine unit vibration data meets the vibration fault feature, perform next step S3; Step S3, determine the misalignment degree of the gas turbine unit shafting, if the bearing bush metal temperature change trend is abnormal, determine it as severe misalignment, otherwise determine it as mild to moderate misalignment; when it is determined as mild to moderate misalignment, perform the step A and the step B; when it is determined as severe misalignment, perform gas turbine unit shafting re-centering; In the step S2, the vibration fault features of gas turbine unit shafting misalignment include: Feature one, in the start-up process of the gas turbine unit from the cranking speed to the first-order critical speed and then to the rated speed, at the first-order critical speed, the shaft vibration of the gas turbine compressor side bearing or the generator turbine side bearing exceeds the set shaft vibration alarm value; Feature two, in the start-up process, at the rated speed, the shaft vibration of at least two of the gas turbine turbine side bearing, the gas turbine compressor side bearing and the generator turbine side bearing approaches or exceeds the set shaft vibration alarm value; Feature three, in the start-up process, at the rated speed, the vibration frequency spectrum analysis result of the gas turbine unit shows that the power frequency is dominant; Feature four, in the start-up process, at the rated speed, the X-direction shaft vibration value and the Y-direction shaft vibration value of the gas turbine turbine side bearing are in opposite phase or close to opposite phase; Feature five, after the gas turbine unit is loaded, the vibration of the gas turbine unit shows correlation with the load change; When the gas turbine unit vibration data meets at least three of the features one to five, it is considered that the gas turbine unit vibration data meets the vibration fault feature; In the step S3, the mild to moderate misalignment refers to that, under the rated speed working condition or the loaded working condition, the bush vibration of the gas turbine compressor side bearing or the gas turbine turbine side bearing is within the range of 4.5mm / s-9.3mm / s, or the shaft vibration of the gas turbine compressor side bearing or the gas turbine turbine side bearing exceeds the set shaft vibration alarm value, and the bearing bush metal temperature change trend is normal.

2. The dynamic balancing method of gas turbine set misalignment vibration problems according to claim 1, characterized in that, The relationship between the second dynamic balance weighting scheme weight and the first dynamic balance weighting scheme weight satisfies: wherein, and are the second dynamic balance weighting scheme weight and the second dynamic balance weighting scheme radius, respectively, and are the first dynamic balance weighting scheme weight and the first dynamic balance weighting scheme radius, respectively.

3. The dynamic balancing method of gas turbine set shafting misalignment vibration problems according to claim 1, characterized in that, Implement the first dynamic balance weight scheme, start up once, and measure the vibration data; then implement the second dynamic balance weight scheme, start up once, and measure the vibration data.

4. The dynamic balancing method of gas turbine set shafting misalignment vibration problems according to claim 1, characterized in that, The first weight plane is located at the middle position of the gas turbine rotor, and the second weight plane is located at the position close to the gas turbine compressor side bearing of the gas turbine rotor.

5. The dynamic balancing method of gas turbine set shafting misalignment vibration problems according to claim 1, characterized in that, In the step A, the influence coefficient of the first plane is obtained by the weighting test on the first plane, and the correction weight and the correction angle of the first plane are calculated, which are respectively the weight and the angle of the first dynamic balance weighting scheme.

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