An engine overall vibration measuring point selection method and system

Abstract

The application discloses an engine whole machine vibration measuring point selection method and system, and the engine whole machine vibration measuring point selection method comprises the following steps: determining an engine whole machine vibration measuring point selection principle; establishing an engine whole machine finite element model; and determining an engine whole machine vibration measuring point through whole machine vibration frequency response characteristic analysis according to the engine whole machine vibration measuring point selection principle and the whole machine finite element model. The selected engine whole machine vibration measuring point can better reflect rotor vibration characteristics (critical speed, unbalanced load change), more rotor vibration characteristic information can be obtained by using less engine whole machine vibration measuring points, and the selected engine whole machine vibration measuring point is more sensitive to rotor vibration characteristic change, and is favorable for vibration safety monitoring of the engine.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of engine testing technology, and particularly relates to an engine whole machine vibration measuring point selection method and system. BACKGROUND

[0002] Whole machine vibration is an inevitable phenomenon in the working of an aero-engine. The additional dynamic load caused by vibration acts on the components of the engine, forcing the structural material to fatigue, thereby reducing the reliability of the engine. Considering that rotor unbalance vibration is the main source of whole machine vibration of the engine, the monitoring of whole machine vibration is mainly the monitoring of rotor vibration of the engine.

[0003] Since the rotor of the engine is located inside the engine, it is difficult to directly monitor its vibration, so generally vibration measuring points are arranged on the external casing of the engine to monitor its vibration. However, whether the positions of the vibration measuring points on the casing can accurately reflect the vibration characteristics of the rotor becomes the key to the success of whole machine vibration monitoring.

[0004] Currently, there are two methods for selecting measuring points for whole machine vibration monitoring. One is to paste strain gauges on the elastic support of the rotor to monitor the vibration of the rotor. As shown in Figure 1 and Figure 2 , this method generally pastes strain gauges on the elastic support of the high-pressure rotor 3#. The other is to arrange acceleration sensors on the external casing of the engine to monitor the vibration of the rotor. In this method, one acceleration sensor is respectively installed on the front and rear end faces of the engine. Considering the installation reliability, the acceleration sensors are generally installed on the casing installation edge through bolts, as shown in Figure 3 .

[0005] The first method of pasting strain gauges on the elastic support of the rotor. This method cannot monitor the vibration characteristics of the low-pressure rotor because it only pastes strain gauges on the elastic support of the high-pressure rotor 3#. In addition, in order to transmit strain gauge data to the data acquisition device, a lead wire needs to be run inside the engine, thereby requiring adaptive modification of some parts. This process is complex and has a certain impact on the safety of related parts, so this method is generally used in the field during the development of the engine, and is not generally used outside the field.

[0006] The second method of arranging acceleration sensors on the external casing of the engine. This method is simple to operate and suitable for use in the field and outside the field. The disadvantage of this method is that the selection of external casing vibration measuring points is mainly based on experience. Since the structures of various types of engines differ significantly, the vibration measuring point arrangement positions passed down based on experience may not accurately reflect the vibration characteristics of the rotor, thereby failing to achieve the purpose of vibration monitoring. Therefore, there is an urgent need to develop a vibration measuring point selection method that can solve the above problems. SUMMARY

[0007] In order to solve the above problems, the application discloses an engine whole machine vibration measuring point selection method, comprising the following steps:

[0008] determining an engine whole machine vibration measuring point selection principle;

[0009] establishing an engine whole machine finite element model;

[0010] determining an engine whole machine vibration measuring point through whole machine vibration frequency response characteristic analysis according to the engine whole machine vibration measuring point selection principle and the whole machine finite element model.

[0011] Further, the engine whole machine vibration measuring point selection principle is as follows:

[0012] The engine whole machine vibration measuring point needs to be sensitive to rotor vibration characteristics, and the engine whole machine vibration measuring point is arranged on a rotor outer transmission radial force path close to a rotor support point in an axial position;

[0013] The engine whole machine vibration measuring point needs to avoid the influence of local vibration of a casing structure;

[0014] In order to ensure the reliability of sensor installation at the engine whole machine vibration measuring point, the engine whole machine vibration measuring point is selected at a casing installation edge or a position for stabilizing a sensor.

[0015] Further, the sensor is an acceleration sensor, a speed sensor or a displacement sensor.

[0016] Further, the establishment of the engine whole machine finite element model comprises the following sub-steps:

[0017] simplifying an engine whole machine structure model;

[0018] performing finite element modeling on the simplified engine whole machine structure model;

[0019] checking structural characteristic parameters of the engine whole machine finite element model.

[0020] Further, the checking is error analysis on mass and mass center position of the engine whole machine finite element model and a stator component finite element model, and error analysis on mass and moment of inertia of a rotor component finite element model.

[0021] Further, the simplification of the engine whole machine structure model comprises the following specific steps:

[0022] the shape and position of a key bearing structure of the engine are maintained to ensure accurate simulation of mechanical characteristics and vibration characteristics of a bearing system;

[0023] For the reduction gear box or flame tube of the engine, the structure shape is retained and the material density is adjusted to ensure the mass of the corresponding structure is equal; for the bolt, conduit or sealing member of the engine, the structure is ignored and only the mass is added to the connected load-bearing structure;

[0024] The local opening, round corner or chamfer on the engine case structure is deleted, and the material density of the local case structure is adjusted to ensure that the mass and the center of mass position of the case structure do not change;

[0025] For the blade structure of the engine, in order to ensure that the mass and the moment of inertia of the blade do not change, a simple ring structure is used to equivalent the blade structure.

[0026] Further, the determination of the engine whole machine vibration measuring point comprises the following sub-steps:

[0027] A plurality of alternative engine whole machine vibration measuring points are preliminarily selected on the mounting edge of the engine external case;

[0028] The vibration frequency response characteristics of the plurality of alternative engine whole machine vibration measuring points are determined;

[0029] According to the vibration frequency response characteristics, the final engine whole machine vibration measuring point is determined.

[0030] An engine whole machine vibration measuring point selection system comprises:

[0031] A determination unit for determining an engine whole machine vibration measuring point selection principle;

[0032] A model unit for establishing an engine whole machine finite element model;

[0033] A selection unit for determining an engine whole machine vibration measuring point through whole machine vibration frequency response characteristic analysis according to the engine whole machine vibration measuring point selection principle and the whole machine finite element model.

[0034] Further, the model unit is specifically used for:

[0035] Simplifying the engine whole machine structure model;

[0036] Carrying out finite element modeling on the simplified engine whole machine structure model;

[0037] Checking the structural characteristic parameters of the engine whole machine finite element model.

[0038] Further, the model unit is specifically used for:

[0039] The shape and position of the key load-bearing structure of the engine are maintained to ensure accurate simulation of the mechanical properties and vibration properties of the load-bearing system;

[0040] For the reduction gear box or flame tube of the engine, the structure shape is reserved and the material density is adjusted to ensure the mass of the corresponding structure is equal; for the bolt, conduit or sealing member of the engine, the structure is ignored and only the mass is added to the connected load-bearing structure;

[0041] The local opening, round corner or chamfer on the engine case structure is deleted, and the material density of the local case structure is adjusted to ensure the mass and the center of mass position of the case structure do not change;

[0042] For the blade structure of the engine, in order to ensure the mass and the moment of inertia of the blade do not change, a simple ring structure is used to equivalent the blade structure.

[0043] Further, the selecting unit is specifically used for:

[0044] A plurality of alternative engine whole machine vibration measuring points are initially selected on the mounting edge of the engine external case;

[0045] The vibration frequency response characteristics of the plurality of alternative engine whole machine vibration measuring points are determined;

[0046] According to the vibration frequency response characteristics, the final engine whole machine vibration measuring point is determined.

[0047] Compared with the prior art, the beneficial effects of the present application are:

[0048] 1) The selected engine whole machine vibration measuring point can better reflect the rotor vibration characteristics (critical speed, unbalanced load change, etc.);

[0049] 2) Fewer engine whole machine vibration measuring points can be used to obtain more rotor vibration characteristic information;

[0050] 3) The selected engine whole machine vibration measuring point is more sensitive to the change of the rotor vibration characteristics, which is conducive to the vibration safety monitoring of the engine.

[0051] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be realized and obtained by the processes described in the specification, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0052] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0053] Figure 1 Typical engine partial structure diagram is shown;

[0054] Figure 2 Engine elastic support paste strain gauge diagram is shown;

[0055] Figure 3 Engine external casing sensor installation diagram is shown;

[0056] Figure 4 Engine external casing multiple engine whole machine vibration measuring point selection position diagram is shown;

[0057] Figure 5 Engine whole machine vibration measuring point C1, C2 vibration speed response curve with engine working state change is shown;

[0058] Figure 6 Engine whole machine vibration measuring point C3, C4 vibration speed response curve with engine working state change is shown;

[0059] Figure 7 Engine whole machine vibration measuring point C5, C6 vibration speed response curve with engine working state change is shown;

[0060] Figure 8 Engine whole machine vibration measuring point C1 sensitivity to unbalanced load change diagram is shown;

[0061] Figure 9 Engine whole machine vibration measuring point C2 sensitivity to unbalanced load change diagram is shown;

[0062] Figure 10 Engine whole machine vibration measuring point C3 sensitivity to unbalanced load change diagram is shown;

[0063] Figure 11 Engine whole machine vibration measuring point C4 sensitivity to unbalanced load change diagram is shown;

[0064] Figure 12 Engine whole machine vibration measuring point C5 sensitivity to unbalanced load change diagram is shown;

[0065] Figure 13 Engine whole machine vibration measuring point C6 sensitivity to unbalanced load change diagram is shown. DETAILED DESCRIPTION

[0066] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0067] The engine whole machine vibration measuring point selection method provided by the present application comprises the following steps:

[0068] determining an engine whole machine vibration measuring point selection principle;

[0069] establishing an engine whole machine finite element model;

[0070] determining an engine whole machine vibration measuring point through whole machine vibration frequency response characteristic analysis according to the engine whole machine vibration measuring point selection principle and the whole machine finite element model. Wherein, the relationship between the amplitude of the corresponding output signal and the frequency is called vibration frequency response characteristic by inputting vibration loads with different frequencies into the vibration system.

[0071] As shown in Figure 4 , in combination with the structural features of the contemporary advanced turboshaft engine and the installation requirements of the sensor, the following engine whole machine vibration measuring point selection principle should be met when selecting the engine whole machine vibration measuring point:

[0072] The engine whole machine vibration measuring point should be sensitive to the rotor vibration characteristics, and the engine whole machine vibration measuring point should be arranged as close as possible to the rotor outer transmission radial force path at the axial position close to the rotor support point;

[0073] The engine whole machine vibration measuring point should avoid the influence of local vibration of the casing structure;

[0074] In order to ensure the reliability of the sensor installation at the engine whole machine vibration measuring point, the engine whole machine vibration measuring point is generally selected at the casing installation edge or other positions where the sensor can be stably installed. Wherein, the sensor is an acceleration sensor, a speed sensor or a displacement sensor.

[0075] In order to make the selected engine whole machine vibration measuring point reflect the vibration characteristics (critical speed, unbalanced load change, etc.) of the rotor, engine whole machine frequency response analysis is required, and the prerequisite for analysis is to establish a high-fidelity engine whole machine finite element model. Wherein, the vibration characteristics generally refer to the characteristics of all vibration physical quantities, including response, mode shape, frequency, etc.

[0076] Establishing the engine whole machine finite element model comprises the following sub-steps:

[0077] simplifying the engine whole machine structural model;

[0078] The simplified engine overall structure model is subjected to finite element modeling;

[0079] The structural characteristic parameters of the engine overall finite element model are checked.

[0080] The overall finite element model comprises a rotor component finite element model and a stator component finite element model. The rotor component finite element model comprises a high-pressure rotor finite element model and a low-pressure rotor finite element model.

[0081] In view of the complexity of the engine structure, the engine overall structure model is properly simplified, and the specific steps are as follows:

[0082] 1) The basic structural characteristics such as the shape and position of the key load-bearing structures (such as various load-bearing casings and load-bearing frames) of the engine are kept unchanged, so as to ensure the accurate simulation of the mechanical characteristics and vibration characteristics of the load-bearing system; wherein the load-bearing system is composed of multiple load-bearing structures.

[0083] 2) The stator components with small load-bearing or accessories have a low impact on the dynamic characteristics of the overall engine, and only generate inertial load or impact load on the load-bearing system due to their own mass during take-off, landing or maneuvering flight. Therefore, the shape of these components can be greatly simplified in modeling. For the accessory structures with large mass in the engine, such as the reduction gear box and the flame tube, the structural shape is retained, and the material density is adjusted to ensure the mass of the corresponding structure; for the bolts, pipes, sealing components and other components with relatively small mass in the engine, the structure is ignored in modeling, and only the mass is added to the load-bearing structure connected thereto.

[0084] 3) The local openings, round corners, chamfers and other detailed structures on the casing structures with small impact on the mechanical characteristics of the overall engine are deleted, and the material density of the local casing structure is adjusted to ensure that the mass and center of mass of the casing structure do not change.

[0085] 4) For the blade structure of the engine, a simple circular ring structure is used to equivalently replace the blade structure to ensure the mass and moment of inertia of the blade unchanged.

[0086] In order to ensure that the engine overall finite element model can accurately reflect the mass and stiffness distribution of the engine overall structure model, the mass and center of mass of the engine overall finite element model and the stator component finite element model are subjected to error analysis, and the mass and moment of inertia of the rotor component finite element model are subjected to error analysis.

[0087] The finite element models of each component in the rotor assembly were checked. As can be seen from Table 1, the errors of the mass and moment of inertia of each component in the finite element model of the rotor assembly and the rotor assembly structural model are within 10%, which meets the engineering design requirements. That is, the finite element models of each component in the rotor assembly can accurately reflect the mass and stiffness distribution of the rotor assembly structural model.

[0088] Table 1 Verification data of finite element model of rotor component

[0089]

[0090] The finite element models of each component in the stator were checked. As can be seen from Table 2, the errors of the mass and centroid position of each component in the finite element model of the stator are within 10% compared with the structural model of the stator, which meets the engineering design requirements. That is, the finite element models of each component in the stator can accurately reflect the mass and stiffness distribution of the structural model of the stator.

[0091] Table 2 Verification data of finite element model of stator component

[0092]

[0093] As shown in Table 3, the finite element model of the whole machine was checked. The error between the mass and centroid position of the finite element model of the whole machine and the whole machine structural model is within 10%, which meets the engineering design requirements. That is, the finite element model of the whole machine can accurately reflect the mass and stiffness distribution of the whole machine structural model.

[0094] Table 3 Verification data of the whole machine finite element model

[0095]

[0096] Determining the vibration measurement points for the entire engine includes the following sub-steps:

[0097] 1) Based on the reliability requirements of sensor installation, several alternative engine vibration measurement points were initially selected on the mounting side of the external engine casing.

[0098] like Figure 4 As shown, based on the principle of selecting vibration measurement points for the entire engine, and considering the reliability of sensor installation at these measurement points, six locations on the external casing of the engine are initially selected as vibration measurement points for the entire engine. These include C1 and C2 in the intake casing, C3 in the compressor casing, C4 in the combustion chamber casing, and C5 and C6 in the turbine casing. Among these, the vibration measurement point C1 is equipped with an accessory device suitable for sensor installation, while the other vibration measurement points are all located on the casing mounting edge.

[0099] 2) determining the vibration frequency response characteristics of the plurality of the alternative engine overall vibration measuring points in different working states of the engine; wherein the different working states refer to the running states of the engine under various loads, and the rotational speeds of the engine rotor are different in various states, so the vibration conditions are also different;

[0100] Considering that the rotor will cause a sudden increase in vibration when passing through the critical speed, according to the requirement that the engine overall vibration measuring point should be sensitive to the vibration characteristics of the rotor, the engine overall vibration measuring point should be able to represent the vibration increase characteristics of the rotor when passing through the critical speed. Based on this, the critical speed of the engine rotor and the vibration frequency response characteristics of each alternative engine overall vibration measuring point in different working states are analyzed, wherein the critical speed of the rotor in the working speed range is shown in Table 4. As shown in Table 4, the engine overall vibration measuring point C1 has a vibration velocity response peak value near the high-pressure rotor frequency 405 Hz and the low-pressure rotor frequency 205 Hz, and the corresponding frequency is consistent with the 2nd order critical speed of the high-pressure rotor and the 2nd order critical speed of the low-pressure rotor; the engine overall vibration measuring point C2 has a vibration velocity response peak value near the low-pressure rotor frequency 108 Hz, and the corresponding frequency is consistent with the 1st order critical speed of the low-pressure rotor. As shown in Table 4, the engine overall vibration measuring point C3 has a vibration velocity response peak value near the high-pressure rotor frequency 200 Hz and the low-pressure rotor frequency 108 Hz, and the corresponding frequency is consistent with the 1st order critical speed of the high-pressure rotor and the 1st order critical speed of the low-pressure rotor; the engine overall vibration measuring point C4 does not have a vibration velocity response peak value near the critical speed of the high-pressure rotor and the low-pressure rotor. As shown in Table 4, the engine overall vibration measuring points C5 and C6 have a vibration velocity response peak value near the high-pressure rotor frequency 200 Hz and the low-pressure rotor frequency 108 Hz, and the corresponding frequency is consistent with the 1st order critical speed of the high-pressure rotor and the 1st order critical speed of the low-pressure rotor. Figure 5 Figure 6 Figure 7

[0101] Table 4 Critical speed of engine rotor

[0102]

[0103] ​​​Since the rotor vibration increases sharply near the critical speed, the corresponding engine overall vibration measuring point must also present this characteristic. Combining the vibration velocity response curves of each alternative engine overall vibration measuring point with the engine operating state, the engine overall vibration measuring point position that can accurately reflect the vibration frequency response characteristics of each order critical speed of the rotor can be obtained, as shown in Table 5. The engine overall vibration measuring points C2, C3, C5 and C6 can reflect the vibration frequency response characteristics of the first order critical speed of the high-pressure rotor, the engine overall vibration measuring point C1 can reflect the vibration frequency response characteristics of the second order critical speed of the high-pressure rotor, the engine overall vibration measuring points C2, C3, C5 and C6 can reflect the vibration frequency response characteristics of the first order critical speed of the low-pressure rotor, and the engine overall vibration measuring point C1 can reflect the vibration frequency response characteristics of the second order critical speed of the low-pressure rotor.

[0104] Table 5 Engine overall vibration measuring point position reflecting vibration frequency response characteristics of each order critical speed of the rotor

[0105]

[0106] 3) Determine the vibration frequency response characteristics of a plurality of the alternative engine overall vibration measuring points under unbalanced load changes; the unbalanced load change refers to the change of the unbalanced centrifugal force of the rotor due to some reasons (such as scraping) during operation;

[0107] The rotor unbalanced load changes due to factors such as connection state changes, rotor icing and blade wear during operation, thereby causing the rotor vibration characteristics to change sharply. According to the requirement that the engine overall vibration measuring point should be sensitive to the vibration characteristics of the rotor, the engine overall vibration measuring point should also be able to reflect the vibration characteristics of the vibration velocity response change caused by the unbalanced load change of the rotor. Based on this, the vibration frequency response characteristics of each alternative engine overall vibration measuring point under the unbalanced load change of the engine are analyzed, as shown in Table 7. The engine overall vibration measuring point C1 is highly sensitive (more than 50%, see Table 6 for specific data) to the vibration velocity response of the high-pressure rotor component caused by the unbalanced load change of the first stage disk of the compressor, highly sensitive (between 15% and 50%, see Table 9 for specific data) to the total vibration velocity response caused by the unbalanced load change of the second stage disk of the power turbine, highly sensitive (more than 50%, see Table 9 for specific data) to the vibration velocity response of the low-pressure rotor component, and low sensitivity (less than 15%) to the total vibration velocity response and the vibration velocity response of the rotor component caused by other unbalanced loads. As shown in Table 8, the engine overall vibration measuring point C1 is highly sensitive (more than 50%, see Table 6 for specific data) to the vibration velocity response of the high-pressure rotor component caused by the unbalanced load change of the first stage disk of the compressor, low sensitivity (less than 15%) to the total vibration velocity response caused by the unbalanced load change of the second stage disk of the power turbine, low sensitivity (less than 15%) to the vibration velocity response of the low-pressure rotor component, and low sensitivity (less than 15%) to the total vibration velocity response and the vibration velocity response of the rotor component caused by other unbalanced loads. Figure 8 Figure 9 ​As shown, the engine overall vibration measuring point C2 is sensitive to the total vibration velocity response caused by the imbalance load change at the first stage disk of the compressor (more than 50%, see Table 6 for specific data), and the vibration velocity response of the high-pressure rotor component is also very high (more than 50%, see Table 6 for specific data). The total vibration velocity response caused by the imbalance load change at the second stage disk of the power turbine is relatively high (between 15% and 50%, see Table 9 for specific data), and the vibration velocity response of the low-pressure rotor component is very high (more than 50%, see Table 9 for specific data). The total vibration velocity response and the vibration velocity response of the rotor component caused by other imbalance loads are relatively low (less than 15%). Figure 10 As shown, the engine overall vibration measuring point C3 is sensitive to the total vibration velocity response caused by the imbalance load change at the first stage disk of the compressor (more than 50%, see Table 6 for specific data), the vibration velocity response of the low-pressure rotor component, and the vibration velocity response of the high-pressure rotor component are also very high (more than 50%, see Table 6 for specific data). The vibration velocity response of the high-pressure rotor component caused by the imbalance load change at the centrifugal impeller is relatively high (between 15% and 50%, see Table 7 for specific data), the vibration velocity response of the high-pressure rotor component caused by the imbalance load change at the second stage disk of the gas turbine is relatively high (between 15% and 50%, see Table 8 for specific data), the vibration velocity response of the low-pressure rotor component caused by the imbalance load change at the second stage disk of the power turbine is very high (more than 50%, see Table 9 for specific data). The total vibration velocity response and the vibration velocity response of the rotor component caused by other imbalance loads are relatively low (less than 15%, see Table 9 for specific data). Figure 11 As shown, the engine overall vibration measuring point C4 is sensitive to the total vibration velocity response caused by the imbalance load change at the first stage disk of the compressor (more than 50%, see Table 6 for specific data), and the vibration velocity response of the high-pressure rotor component is also very high (more than 50%, see Table 6 for specific data). The vibration velocity response of the high-pressure rotor component caused by the imbalance load change at the centrifugal impeller is relatively high (between 15% and 50%, see Table 7 for specific data), the total vibration velocity response and the vibration velocity response of the high-pressure rotor component caused by the imbalance load change at the second stage disk of the gas turbine are relatively high (between 15% and 50%, see Table 8 for specific data), the total vibration velocity response caused by the imbalance load change at the second stage disk of the power turbine is relatively high (between 15% and 50%, see Table 9 for specific data), and the vibration velocity response of the low-pressure rotor component is very high (more than 50%, see Table 9 for specific data). The total vibration velocity response and the vibration velocity response of the rotor component caused by other imbalance loads are relatively low (less than 15%). Figure 12As shown, the engine overall vibration measuring point C5 is sensitive to the total vibration velocity response caused by the imbalance load change at the first stage disk of the compressor (between 15% and 50%, see Table 6 for specific data), and the vibration velocity response of the high pressure rotor component is very high (more than 50%, see Table 6 for specific data). The vibration velocity response of the high pressure rotor component caused by the imbalance load change at the second stage disk of the gas turbine is relatively high (between 15% and 50%, see Table 8 for specific data). The vibration velocity response of the total and the low pressure rotor component caused by the imbalance load change at the second stage disk of the power turbine are very high (more than 50%, see Table 9 for specific data). The vibration velocity response of the total and the rotor component caused by other imbalance loads are relatively low (less than 15%). Figure 13 As shown, the engine overall vibration measuring point C6 is sensitive to the total vibration velocity response and the vibration velocity response of the high pressure rotor component caused by the imbalance load change at the first stage disk of the compressor (more than 50%, see Table 6 for specific data). The vibration velocity response of the total caused by the imbalance load change at the second stage disk of the gas turbine is relatively high (between 15% and 50%, see Table 8 for specific data). The vibration velocity response of the total caused by the imbalance load change at the second stage disk of the power turbine is relatively high (between 15% and 50%, see Table 9 for specific data). The vibration velocity response of the low pressure rotor component is very high (more than 50%, see Table 9 for specific data). The vibration velocity response of the total and the rotor component caused by other imbalance loads are relatively low (less than 15%).

[0108] The imbalance sensitivity of the engine overall vibration measuring point is calculated by the following formula:

[0109]

[0110] Wherein, ε is the imbalance sensitivity of the engine overall vibration measuring point; V 原 is the vibration velocity response of the engine overall vibration measuring point under the original imbalance load; V 后 is the vibration velocity response of the engine overall vibration measuring point after the imbalance load change. In formula 1, the imbalance sensitivity obtained by using the total vibration velocity response of the engine overall vibration measuring point for calculation is called the total vibration velocity response sensitivity. The imbalance sensitivity obtained by using the vibration velocity response of the low / high pressure rotor component of the engine overall vibration measuring point for calculation is called the vibration velocity response sensitivity of the low / high pressure rotor component. The imbalance sensitivity refers to the change degree of the rotor vibration response (vibration displacement, vibration velocity, vibration acceleration) of the rotor under the action of different imbalance loads. The vibration velocity response refers to the vibration velocity of the vibration system under the action of the exciting load.

[0111] Table 6 Engine overall vibration measuring point unbalance sensitivity under the condition of compressor first stage disk unbalance load change

[0112]

[0113]

[0114] Table 7 Engine overall vibration measuring point unbalance sensitivity under the condition of centrifugal impeller unbalance load change

[0115]

[0116] Table 8 Engine overall vibration measuring point unbalance sensitivity under the condition of gas turbine second stage disk unbalance load change

[0117]

[0118]

[0119] Table 9 Engine overall vibration measuring point unbalance sensitivity under the condition of power turbine second stage disk unbalance load change

[0120]

[0121] Considering that vibration energy is proportional to the square of vibration velocity response, the engine overall vibration measuring point can be selected by vibration energy change sensitivity coefficient, and the greater the vibration energy change sensitivity coefficient, the more sensitive the engine overall vibration measuring point to the change of overall vibration energy caused by the rotor unbalance load. The vibration energy change sensitivity coefficient is calculated by the following formula:

[0122] δ = ε 2 总 + ε 2 转子 2)

[0123] Wherein, δ is the vibration energy change sensitivity coefficient; ε 总 is the overall vibration velocity response sensitivity of the engine overall vibration measuring point under the condition of unbalance load change; ε 转子 is the vibration velocity response sensitivity of the high pressure rotor component and the vibration velocity response sensitivity of the low pressure rotor component.

[0124] Based on the vibration energy change sensitive coefficient, see Table 10, the engine whole machine vibration measuring point position corresponding to the vibration frequency response characteristics of the rotor unbalance load change can be obtained, see Table 11. The engine whole machine vibration measuring points C3 and C4 reflect the vibration frequency response characteristics of the compressor first-stage disk unbalance load change, the engine whole machine vibration measuring points C3 and C4 reflect the vibration frequency response characteristics of the centrifugal impeller unbalance load change, the engine whole machine vibration measuring points C3 and C4 reflect the vibration frequency response characteristics of the gas turbine second-stage disk unbalance load change, and the engine whole machine vibration measuring points C5 and C6 reflect the vibration frequency response characteristics of the power turbine second-stage disk unbalance load change.

[0125] Table 10: Vibration energy change sensitive coefficient of each engine whole machine vibration measuring point

[0126]

[0127] Table 11: Engine whole machine vibration measuring point position reflecting the vibration frequency response characteristics of the rotor unbalance load change

[0128]

[0129]

[0130] 4) According to the pros and cons of the rotor vibration characteristics that can be reflected by the vibration frequency response characteristics of a plurality of the above-mentioned alternative engine whole machine vibration measuring points, the final engine whole machine vibration measuring point is determined.

[0131] The engine whole machine vibration measuring points C1, C3 and C5 are finally selected as the engine whole machine vibration measuring point position, see Table 12, wherein the engine whole machine vibration measuring point C1 can reflect the high and low pressure rotor 2nd order critical speed, the engine whole machine vibration measuring point C3 can reflect the high and low pressure rotor 1st order critical speed and low pressure rotor unbalance load change, and the engine whole machine vibration measuring point C5 can reflect the high pressure rotor unbalance load change.

[0132] Table 12: Engine whole machine vibration measuring point selection position

[0133]

[0134] The engine whole machine vibration measuring point selected by the above-mentioned method can better reflect the rotor vibration characteristics (critical speed, unbalance load change, etc.), can obtain more rotor vibration characteristic information using fewer engine whole machine vibration measuring points, is more sensitive to the rotor vibration characteristic change, and is beneficial to the vibration safety monitoring of the engine.

[0135] Based on the above-mentioned engine whole machine vibration measuring point selection method, the present application proposes an engine whole machine vibration measuring point selection system, which comprises:

[0136] A determining unit is configured to determine an engine overall vibration measuring point selection principle.

[0137] A modeling unit is configured to establish an engine overall finite element model.

[0138] A selecting unit is configured to determine an engine overall vibration measuring point according to the engine overall vibration measuring point selection principle and the overall finite element model, and through overall vibration frequency response characteristic analysis.

[0139] The modeling unit is specifically configured to:

[0140] simplify an engine overall structure model;

[0141] perform finite element modeling on the simplified engine overall structure model;

[0142] check structural characteristic parameters of the engine overall finite element model.

[0143] The modeling unit is specifically configured to:

[0144] maintain shapes and positions of key load-bearing structures of the engine to ensure accurate simulation of mechanical properties and vibration properties of the load-bearing system;

[0145] for a reduction gear box or a flame tube of the engine, keep a structure shape and adjust material density to ensure equal mass of the corresponding structure; for a bolt, a conduit or a sealing member of the engine, ignore the structure and only add mass to the connected load-bearing structure;

[0146] delete local openings, round corners or chamfers on the engine casing structure, while adjusting material density of a local casing structure to ensure that mass and center of mass of the casing structure do not change;

[0147] for a blade structure of the engine, to ensure that mass and moment of inertia of the blade do not change, a simple ring structure is used to equivalently replace the blade structure.

[0148] The selecting unit is specifically configured to:

[0149] preliminarily select a plurality of candidate engine overall vibration measuring points on an engine external casing mounting edge;

[0150] determine vibration frequency response characteristics of the plurality of candidate engine overall vibration measuring points;

[0151] determine a final engine overall vibration measuring point according to the vibration frequency response characteristics.

[0152] Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood that modifications can be made to the foregoing embodiments, or additional implementations can be implemented, without departing from the spirit and scope of the inventive subject matter. Accordingly, the present application is not limited to the implementations described herein, but is intended to be defined by the claims set forth below, and equivalents thereof.

Claims

1. An engine overall vibration measuring point selection method, characterized by, Includes the following steps: Determine the principles for selecting vibration measurement points for the entire engine; Establish the finite element model of the entire engine; Based on the selection principle of vibration measurement points for the entire engine and the finite element model of the entire engine, the vibration measurement points for the entire engine are determined through the analysis of the vibration frequency response characteristics of the entire engine. The process of determining the vibration measurement points of the entire engine includes the following sub-steps: Based on the reliability requirements of sensor installation, several alternative engine vibration measurement points were initially selected on the mounting side of the engine's external casing. Based on the characteristic of the rotor's vibration suddenly increasing near the critical speed, and combined with the vibration velocity response magnitude of each candidate engine vibration measurement point changing with the engine's operating state, engine vibration measurement points that can accurately reflect the vibration frequency response characteristics of the rotor at each critical speed are obtained. Based on the relationship between the magnitudes of the vibration energy change sensitivity coefficients of each candidate engine vibration measurement point under unbalanced load changes, the engine vibration measurement points corresponding to the vibration frequency response characteristics reflecting the rotor unbalanced load changes are obtained. Based on the engine vibration measurement points corresponding to the vibration frequency response characteristics of rotor unbalanced load changes, the order of priority of rotor unbalanced loads reflecting rotor critical speed, and the order of priority of rotor unbalanced loads corresponding to the engine vibration measurement points corresponding to the vibration frequency response characteristics of rotor unbalanced load changes, the final engine vibration measurement points are selected.

2. The method according to claim 1, wherein The specific principles for selecting vibration measurement points for the entire engine are as follows: The vibration measurement points of the entire engine need to be sensitive to the vibration characteristics of the rotor. The vibration measurement points of the entire engine should be arranged on the path of the radial force transmitted from the rotor to the rotor near the rotor support in the axial position. The vibration measurement points for the entire engine should avoid the influence of local vibrations in the casing structure. To ensure the reliability of the sensor installation at the engine vibration measurement point, the engine vibration measurement point is selected at the mounting edge of the casing or at a location where the sensor is securely mounted.

3. The method according to claim 2, wherein The sensor is an acceleration sensor, a velocity sensor, or a displacement sensor.

4. The method according to claim 1, wherein The establishment of the finite element model of the engine includes the following sub-steps: The overall engine structural model was simplified. Finite element modeling was performed on the simplified engine overall structure model; The structural characteristic parameters of the finite element model of the engine were verified.

5. The method according to claim 4, wherein The verification involves performing error analysis on the mass and center of mass position of the engine whole finite element model and the stator component finite element model, and performing error analysis on the mass and moment of inertia of the rotor component finite element model.

6. The method according to claim 4, wherein The specific steps for simplifying the overall engine structural model are as follows: Maintain the shape and position of the engine's key load-bearing structures to ensure accurate simulation of the mechanical and vibration characteristics of the load-bearing system; For the reduction gearbox or flame tube of the engine, the structural shape is retained, and the material density is adjusted to ensure that the mass of the corresponding structure is equal; for the bolts, ducts or sealing components of the engine, the structure is ignored, and the mass is only added to the connected load-bearing structure. Remove the local openings, fillets, or chamfers on the engine casing structure, and adjust the local material density of the casing structure to ensure that the mass and center of gravity of the casing structure do not change. For the blade structure of the engine, a simple ring structure is used to equivalently ensure the mass and moment of inertia of the blade.

7. A system for selecting vibration measurement points for an entire engine, characterized in that, The method comprises the steps of: A determination unit is configured to determine an engine overall vibration measuring point selection principle; A model unit is configured to establish an engine overall finite element model; wherein the overall finite element model comprises a stator finite element model, a high-pressure rotor finite element model and a low-pressure rotor finite element model; A selection unit is configured to determine an engine overall vibration measuring point according to the engine overall vibration measuring point selection principle and the overall finite element model through overall vibration frequency response characteristic analysis. The determination of the engine overall vibration measuring point comprises the following sub-steps: According to the reliability requirement of sensor installation, a plurality of alternative engine overall vibration measuring points are preliminarily selected on the engine outer casing installation edge; According to the vibration sudden increase characteristic of the rotor near the critical speed, in combination with the vibration speed response size variation curve of each alternative engine overall vibration measuring point with the engine working state, an engine overall vibration measuring point capable of accurately reflecting the vibration frequency response characteristic of each order critical speed of the rotor is obtained; According to the vibration energy variation sensitive coefficient size relationship of each alternative engine overall vibration measuring point under the unbalanced load variation, an engine overall vibration measuring point corresponding to the vibration frequency response characteristic of the unbalanced load variation of the rotor is obtained; According to the advantages and disadvantages order of the rotor unbalanced load corresponding to the vibration frequency response characteristic of the unbalanced load variation of the rotor and the rotor unbalanced load of the engine overall vibration measuring point corresponding to the vibration frequency response characteristic of the unbalanced load variation of the rotor, a final engine overall vibration measuring point is selected.

8. The engine overall vibration measurement point selection system according to claim 7, characterized by, The model unit is specifically configured to: simplify the engine overall structure model; perform finite element modeling on the simplified engine overall structure model; check the structural characteristic parameters of the engine overall finite element model.

9. The engine overall vibration measurement point selection system according to claim 8, characterized by, The model unit is specifically configured to: maintain the shape and position of the key load-bearing structure of the engine to ensure accurate simulation of the mechanical characteristics and vibration characteristics of the load-bearing system; for the reduction gear box or flame tube of the engine, the structure shape is retained and the material density is adjusted to ensure the mass of the corresponding structure is equal; for the bolts, pipes or sealing members of the engine, the structure is ignored and only the mass is added to the connected load-bearing structure; local holes, fillets or chamfers on the engine casing structure are deleted, and the material density of the local casing structure is adjusted to ensure that the mass and center of mass of the casing structure do not change; for the blade structure of the engine, a simple ring structure is used to equivalently ensure the mass and moment of inertia of the blade.

10. The engine overall vibration measurement point selection system according to claim 7, characterized by, The selection unit is specifically configured to: preliminarily select a plurality of alternative engine overall vibration measuring points on the engine outer casing installation edge; determine the vibration frequency response characteristics of the plurality of alternative engine overall vibration measuring points; determine the final engine overall vibration measuring point according to the vibration frequency response characteristics.

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