CN114117862A - Engine whole machine vibration measuring point selection method and system - Google Patents
Engine whole machine vibration measuring point selection method and system Download PDFInfo
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Abstract
The invention discloses a method and a system for selecting vibration measuring points of a whole engine, wherein the method for selecting the vibration measuring points of the whole engine comprises the following steps: determining a selection principle of a whole engine vibration measuring point; establishing a finite element model of the whole engine; and determining the vibration measuring point of the whole engine through the analysis of the vibration frequency response characteristic of the whole engine according to the selection principle of the vibration measuring point of the whole engine and a finite element model of the whole engine. The selected vibration measuring points of the whole engine can better reflect the vibration characteristics (critical rotating speed and unbalanced load change) of the rotor; more rotor vibration characteristic information can be obtained by using fewer engine whole machine vibration measuring points; the selected vibration measuring point of the whole engine is more sensitive to the change of the vibration characteristic of the rotor, and is beneficial to carrying out vibration safety monitoring on the engine.
Description
Technical Field
The invention belongs to the technical field of engine testing, and particularly relates to a method and a system for selecting a vibration test point of a complete engine.
Background
The vibration of the whole aircraft engine is an inevitable phenomenon in the working process of the aircraft engine, and an additional dynamic load generated by the vibration acts on an engine component to force a structural material to be fatigued, so that the reliability of the engine is reduced. Considering that the unbalanced vibration of the rotor is a main source of the vibration of the whole engine, the monitoring of the vibration of the whole engine is mainly the monitoring of the vibration of the rotor of the engine.
Because the engine rotor is positioned in the engine and is difficult to directly monitor the vibration of the engine rotor, the vibration condition of the engine rotor is generally monitored by arranging vibration measuring points on an external casing of the engine, but whether the vibration characteristics of the rotor can be accurately reflected by the positions of the selected casing vibration measuring points becomes the key for the success or failure of the vibration monitoring of the whole engine.
At present, there are two methods for selecting measuring points for monitoring the vibration of the whole machine, one is to paste a strain gauge on an elastic support of a rotor to monitor the vibration of the rotor. As shown in fig. 1 and 2, this method generally applies strain foil patch to the high pressure rotor # 3 elastic support in the low temperature region. Another is to arrange an acceleration sensor on the engine outer casing to monitor the vibration of the rotor. In this method, an acceleration sensor is mounted on each of the front and rear end faces of the engine, and the acceleration sensor is mounted on the casing mounting side by bolts in consideration of mounting reliability, as shown in detail in fig. 3.
The first method is to attach a strain gauge to an elastic support of a rotor. In the method, the patch is only arranged on the 3# elastic support of the high-pressure rotor, so that the vibration characteristic of the low-pressure rotor cannot be monitored. In addition, in order to transmit the strain gauge data to the data acquisition equipment, a lead wire needs to be arranged inside the engine, so that part of parts are subjected to adaptive transformation, the process is complex, and the safety of the related parts is also influenced to a certain extent, so that the method is generally used in an on-site mode in the engine development stage, and is not adopted outside the on-site mode.
A second method arranges an acceleration sensor on an engine outer casing. The method is simple to operate and is suitable for use both in the field and out of the field. The method has the defects that the selection of the vibration measuring points of the external casing is mainly based on experience at present, and the arrangement positions of the vibration measuring points transmitted by the experience can not accurately reflect the vibration characteristics of the rotor because the structures of engines of various types have obvious differences, so that the aim of vibration monitoring is fulfilled. Therefore, there is a need to develop a method for selecting a vibration measurement point that can solve the above problems.
Disclosure of Invention
Aiming at the problems, the invention discloses a method for selecting a vibration measuring point of a whole engine, which comprises the following steps:
determining a selection principle of a whole engine vibration measuring point;
establishing a finite element model of the whole engine;
and determining the vibration measuring point of the whole engine through the analysis of the vibration frequency response characteristic of the whole engine according to the selection principle of the vibration measuring point of the whole engine and a finite element model of the whole engine.
Furthermore, the principle of selecting the whole engine vibration measuring point is as follows:
the vibration measuring points of the whole engine are required to be sensitive to the vibration characteristics of the rotor, and are arranged on a radial force transmission path of the rotor, the axial position of which is close to the rotor fulcrum;
the vibration measuring point of the whole engine needs to avoid the influence of local vibration of a casing structure;
in order to ensure the reliability of the installation of the sensor at the vibration measuring point of the whole engine, the vibration measuring point of the whole engine is selected at the installation edge of the casing or the position of the stable sensor.
Further, the sensor is an acceleration sensor, a velocity sensor, or a displacement sensor.
Further, the establishing of the engine complete machine finite element model comprises the following substeps:
simplifying the structural model of the whole engine;
finite element modeling is carried out on the simplified engine whole structure model;
and checking the structural characteristic parameters of the finite element model of the whole engine.
Furthermore, the checking is to perform error analysis on the mass and the mass center position of the engine complete machine finite element model and the stator component finite element model, and perform error analysis on the mass and the rotational inertia of the rotor component finite element model.
Furthermore, the specific steps for simplifying the engine complete machine structure model are as follows:
the shape and the position of a key bearing structure of the engine are kept, so that the accurate simulation of the mechanical property and the vibration property of a bearing system is ensured;
for a reduction gear box or a flame tube of the engine, the structural appearance is kept, and the material density is adjusted to ensure that the quality of corresponding structures is equal; for the bolts, the conduits or the sealing components of the engine, the structure is omitted, and the mass is only added on the connected bearing structure;
deleting local holes, fillets or chamfers on the engine case structure, and simultaneously adjusting the local material density of the case structure to ensure that the quality and the mass center position of the case structure are not changed;
for the blade structure of the engine, in order to ensure that the mass and the rotational inertia of the blade are unchanged, the blade structure is equivalent by adopting a circular ring structure with a simple structure.
Further, the step of determining the vibration measuring point of the whole engine comprises the following substeps:
preliminarily selecting a plurality of alternative engine whole machine vibration measuring points at the mounting edge of an external casing of the engine;
determining vibration frequency response characteristics of a plurality of alternative engine whole machine vibration measuring points;
and determining a final vibration measuring point of the whole engine according to the vibration frequency response characteristic.
A system for selecting vibration measuring points of a whole engine comprises:
the determining unit is used for determining a selection principle of the whole engine vibration measuring point;
the model unit is used for establishing a finite element model of the whole engine;
and the selecting unit is used for determining the vibration measuring point of the whole engine through the analysis of the vibration frequency response characteristic of the whole engine according to the selection principle of the vibration measuring point of the whole engine and a finite element model of the whole engine.
Further, the model unit is specifically configured to:
simplifying the structural model of the whole engine;
finite element modeling is carried out on the simplified engine whole structure model;
and checking the structural characteristic parameters of the finite element model of the whole engine.
Further, the model unit is specifically configured to:
the shape and the position of a key bearing structure of the engine are kept, so that the accurate simulation of the mechanical property and the vibration property of a bearing system is ensured;
for a reduction gear box or a flame tube of the engine, the structural appearance is kept, and the material density is adjusted to ensure that the quality of corresponding structures is equal; for the bolts, the conduits or the sealing components of the engine, the structure is omitted, and the mass is only added on the connected bearing structure;
deleting local holes, fillets or chamfers on the engine case structure, and simultaneously adjusting the local material density of the case structure to ensure that the quality and the mass center position of the case structure are not changed;
for the blade structure of the engine, in order to ensure that the mass and the rotational inertia of the blade are unchanged, the blade structure is equivalent by adopting a circular ring structure with a simple structure.
Furthermore, the selecting unit is specifically configured to:
preliminarily selecting a plurality of alternative engine whole machine vibration measuring points at the mounting edge of an external casing of the engine;
determining vibration frequency response characteristics of a plurality of alternative engine whole machine vibration measuring points;
and determining a final vibration measuring point of the whole engine according to the vibration frequency response characteristic.
Compared with the prior art, the invention has the beneficial effects that:
1) the selected vibration measuring points of the whole engine can better reflect the vibration characteristics (critical rotating speed, unbalanced load change and the like) of the rotor;
2) more rotor vibration characteristic information can be obtained by using fewer engine whole machine vibration measuring points;
3) the selected vibration measuring point of the whole engine is more sensitive to the change of the vibration characteristic of the rotor, and is beneficial to carrying out vibration safety monitoring on the engine.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the process particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 illustrates a partial block diagram of a typical engine;
FIG. 2 is a schematic view showing a strain gage attached to an elastic support of an engine;
FIG. 3 shows a schematic diagram of sensor mounting on an engine outer case;
FIG. 4 is a schematic diagram showing a plurality of positions for selecting the vibration measurement points of the whole engine on an external casing of the engine;
FIG. 5 shows the vibration speed response curves of the vibration measuring points C1 and C2 of the whole engine along with the change of the working state of the engine;
FIG. 6 shows the vibration speed response curves of the vibration measuring points C3 and C4 of the whole engine along with the change of the working state of the engine;
FIG. 7 shows the vibration speed response curves of the vibration measuring points C5 and C6 of the whole engine along with the change of the engine working state;
FIG. 8 is a schematic illustrating the sensitivity of engine total machine vibration test point C1 to unbalanced load variations;
FIG. 9 is a schematic diagram illustrating the sensitivity of engine total machine vibration test point C2 to unbalanced load variations;
FIG. 10 is a schematic illustrating the sensitivity of engine total machine vibration test point C3 to unbalanced load variations;
FIG. 11 is a schematic diagram illustrating the sensitivity of engine total machine vibration test point C4 to unbalanced load variations;
FIG. 12 is a schematic illustrating the sensitivity of engine total machine vibration test point C5 to unbalanced load variations;
FIG. 13 shows a graphical representation of the sensitivity of engine total machine vibration test point C6 to unbalanced load variations.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a method for selecting a vibration measuring point of a whole engine, which comprises the following steps:
determining a selection principle of a whole engine vibration measuring point;
establishing a finite element model of the whole engine;
and determining the vibration measuring point of the whole engine through the analysis of the vibration frequency response characteristic of the whole engine according to the selection principle of the vibration measuring point of the whole engine and a finite element model of the whole engine. The excitation loads with different frequencies are input into the vibration system, and the relationship between the amplitude and the frequency of the corresponding output signals is called vibration frequency response characteristics.
As shown in fig. 4, in combination with the structural characteristics of the modern advanced turboshaft engine and the installation requirements of the sensor, the following principle of selecting the whole engine vibration measuring point should be satisfied when the whole engine vibration measuring point is selected:
the vibration measuring points of the whole engine need to be sensitive to the vibration characteristics of the rotor, and the vibration measuring points of the whole engine are arranged on a radial force transmission path of the rotor, the axial position of which is close to the rotor fulcrum, as far as possible;
the vibration measuring point of the whole engine needs to avoid the influence of local vibration of a casing structure;
in order to ensure the reliability of the installation of the sensor at the vibration measuring point of the whole engine, the vibration measuring point of the whole engine is generally selected from a mounting edge of a casing or other positions capable of stabilizing the sensor. Wherein, the sensor is an acceleration sensor, a speed sensor or a displacement sensor.
In order to enable the selected vibration measuring points of the whole engine to reflect the vibration characteristics (critical rotating speed, unbalanced load change and the like) of the rotor, the frequency response analysis of the whole engine is required, and the analysis is based on the premise that a high-fidelity finite element model of the whole engine is established. The vibration characteristics generally refer to characteristics of all vibration physical quantities, including response, mode shape, frequency, and other vibration characteristics.
The establishing of the engine complete machine finite element model comprises the following substeps:
simplifying the structural model of the whole engine;
finite element modeling is carried out on the simplified engine whole structure model;
and checking the structural characteristic parameters of the finite element model of the whole engine.
The complete machine 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.
Considering the complexity of the engine structure, the model of the whole engine structure needs to be simplified properly, and the specific steps are as follows:
1) the basic structural characteristics such as the shape and the position of a key bearing structure (such as each bearing casing and a bearing frame) of the engine are kept unchanged, so that the accurate simulation of the mechanical property and the vibration property of a bearing system is ensured; the bearing system consists of a plurality of bearing structures;
2) the accessory or the static part with small bearing capacity has low influence on the whole dynamic characteristics, and the appearance of the components can be greatly simplified in modeling because the self mass generates the inertia load or impact load effect on a bearing system only during take-off landing or maneuvering flight. For accessory structures with larger mass in the engine, such as a reduction gear box, a flame tube and the like, the structural appearance of the accessory structures is kept, and the material density is adjusted to ensure that the mass of corresponding structures is equal; for bolts, pipes, sealing components and the like with relatively small mass in the engine, the structure of the bolts, the pipes, the sealing components and the like is neglected in modeling, and the mass is only added to the bearing structure connected with the bolts;
3) local openings, fillets, chamfers and other detailed structures on the casing structure, which have small influence on the mechanical properties of the whole engine, are deleted, and meanwhile, the local material density of the casing structure is adjusted, so that the structural quality and the mass center position of the casing are ensured not to be changed;
4) for the blade structure of the engine, in order to ensure that the mass and the rotational inertia of the blade are not changed, the blade structure is equivalent by adopting a circular ring structure with a simple structure.
In order to ensure that the engine complete machine finite element model can accurately reflect the mass and rigidity distribution of the engine complete machine structure model, the mass and the mass center position of the engine complete machine finite element model and the stator component finite element model need to be subjected to error analysis, and the mass and the rotational inertia of the rotor component finite element model need to be subjected to error analysis.
The finite element models of the parts in the rotor component are checked, and as can be seen from table 1, the errors between the mass and the rotational inertia of the finite element models of the parts in the rotor component and the structural model of the rotor component are within 10%, so that the engineering design requirements are met, namely the finite element models of the parts in the rotor component can accurately reflect the mass and the rigidity distribution of the structural model of the rotor component.
TABLE 1 rotor component finite element model checking data
The finite element models of the parts in the stator component are checked, and as can be seen from table 2, the errors between the mass and the mass center of the finite element models of the parts in the stator component and the structural model of the stator component are within 10%, so that the engineering design requirements are met, namely the finite element models of the parts in the stator component can accurately reflect the mass and the rigidity distribution of the structural model of the stator component.
TABLE 2 finite element model checking data for stator parts
As shown in Table 3, the finite element model of the whole machine is checked, the errors of the mass, the centroid position and the structural model of the whole machine are within 10%, and the engineering design requirements are met, namely the finite element model of the whole machine can accurately reflect the mass and the rigidity distribution of the structural model of the whole machine.
TABLE 3 Whole machine finite element model checking data
The method for determining the vibration measuring point of the whole engine comprises the following substeps:
1) according to the reliability requirement of sensor installation, a plurality of alternative engine whole machine vibration measuring points are preliminarily selected at the installation edge of an external casing of the engine;
as shown in fig. 4, according to the reliability of the installation of the sensor at the vibration measuring point of the whole engine in the principle of the selection of the vibration measuring point of the whole engine, the position of the external casing 6 of the engine is preliminarily selected as the position of the vibration measuring point of the whole engine, and the position comprises C1 and C2 positioned on an air inlet casing, C3 positioned on an air compressor casing, C4 positioned on a combustion chamber casing and C5 and C6 positioned on a turbine casing, wherein an accessory device is arranged at the position of the vibration measuring point C1 of the whole engine, the installation of the sensor is suitable, and other vibration measuring points of the whole engine are positioned on the installation edge of the casing.
2) Determining vibration frequency response characteristics of a plurality of alternative engine whole machine vibration measuring points in different working states of the engine; the different working states refer to the running states of the engine under various loads, and the rotating speeds of the rotor of the engine in various states are different, so that the vibration conditions are different;
considering that the rotor vibration is increased suddenly when the rotor passes through the critical rotating speed, according to the requirement that the vibration characteristic of the rotor needs to be sensitive by the vibration measuring point of the whole engine, the vibration measuring point of the whole engine can represent the characteristic that the vibration is increased when the rotor passes through the critical rotating speed. Based on the method, the critical rotating speed of the rotor of the engine and the vibration frequency response characteristics of all optional vibration measuring points of the whole engine in different working states are analyzed, wherein the critical rotating speed of the rotor in the working rotating speed range is shown in a table 4. As shown in fig. 5, a vibration speed response peak exists at the vibration measuring point C1 of the whole engine near the high-pressure rotor frequency of 405Hz and the low-pressure rotor frequency of 205Hz, and the corresponding frequency is consistent with the 2-order critical rotation speed of the high-pressure rotor and the 2-order critical rotation speed of the low-pressure rotor; the vibration speed response peak value exists at the vibration measuring point C2 of the whole engine near the low-pressure rotor frequency 108Hz, and the corresponding frequency is consistent with the 1-order critical rotating speed of the low-pressure rotor. As shown in fig. 6, a vibration speed response peak exists at the vibration measuring point C3 of the whole engine near the high-pressure rotor frequency of 200Hz and the low-pressure rotor frequency of 108Hz, and the corresponding frequency is consistent with the 1-order critical rotation speed of the high-pressure rotor and the 1-order critical rotation speed of the low-pressure rotor; the engine whole machine vibration measuring point C4 has no vibration speed response peak value near the critical rotating speed of the high-pressure rotor and the low-pressure rotor. As shown in fig. 7, vibration speed response peaks exist at vibration speed measurement points C5 and C6 of the whole engine at the high-pressure rotor frequency of 200Hz and the low-pressure rotor frequency of 108Hz, and the corresponding frequencies are consistent with the 1-order critical rotation speed of the high-pressure rotor and the 1-order critical rotation speed of the low-pressure rotor.
TABLE 4 Critical speed of the rotor of the engine
As the rotor vibrates suddenly near the critical rotating speed, the corresponding vibration measuring points of the whole engine also have the characteristic, and the positions of the vibration measuring points of the whole engine, which can accurately reflect the vibration frequency response characteristic of each order of the critical rotating speed of the rotor, can be obtained by combining the change curve of the vibration speed response of each alternative vibration measuring point of the whole engine along with the working state of the engine, as shown in Table 5. The vibration frequency response characteristics of 1-order critical rotating speed of the high-pressure rotor can be reflected by the vibration measuring points C2, C3, C5 and C6 of the whole engine, the vibration frequency response characteristics of 2-order critical rotating speed of the high-pressure rotor can be reflected by the vibration measuring points C1 of the whole engine, the vibration frequency response characteristics of 1-order critical rotating speed of the low-pressure rotor can be reflected by the vibration measuring points C2, C3, C5 and C6 of the whole engine, and the vibration frequency response characteristics of 2-order critical rotating speed of the low-pressure rotor can be reflected by the vibration measuring points C1 of the whole engine.
Table 5 shows the vibration frequency response of each stage of critical speed of rotor
3) Determining the vibration frequency response characteristics of a plurality of alternative engine whole machine vibration measuring points in unbalanced load change; unbalanced load variation refers to unbalanced centrifugal force variation generated by the rotor during operation for some reason (such as scraping);
the rotor unbalance load can be changed due to factors such as connection state change, rotor icing and blade abrasion in the running process of the rotor, so that the rotor vibration characteristic is changed suddenly, and according to the requirement that the vibration characteristic of the rotor needs to be sensitive by the vibration measuring point of the whole engine, the vibration measuring point of the whole engine can also represent the vibration characteristic of vibration speed response change caused by the rotor unbalance load change. Based on the above, the vibration frequency response characteristics of the alternative engine whole machine vibration measuring points under the condition of the unbalanced load change of the engine are analyzed, as shown in fig. 8, the vibration speed response sensitivity of the engine whole machine vibration measuring point C1 to the high-pressure rotor component caused by the unbalanced load change at the primary disc of the compressor is very high (more than 50%, the specific data are shown in table 6), the total vibration speed response sensitivity caused by the unbalanced load change at the secondary disc of the power turbine is very high (between 15% and 50%, the specific data are shown in table 9), the vibration speed response sensitivity of the low-pressure rotor component is very high (more than 50%, the specific data are shown in table 9), and the total vibration speed response sensitivity caused by other unbalanced loads and the vibration speed response sensitivity of the rotor component are both low (less than 15%). As shown in fig. 9, the vibration speed response sensitivity of the whole engine vibration measuring point C2 to the unbalanced load variation at the primary disk of the compressor and the vibration speed response sensitivity of the high-pressure rotor component are both high (more than 50%, see table 6 for specific data), the vibration speed response sensitivity to the unbalanced load variation at the secondary disk of the power turbine is high (between 15% and 50%, see table 9 for specific data), the vibration speed response sensitivity of the low-pressure rotor component is high (more than 50%, see table 9 for specific data), and the vibration speed response sensitivity to the other unbalanced loads and the vibration speed response sensitivity of the rotor component are both low (less than 15%). As shown in FIG. 10, the vibration speed response sensitivity of the whole engine vibration measuring point C3 for the unbalanced load variation at the primary disk of the compressor, the vibration speed response sensitivity of the low-pressure rotor component and the vibration speed response sensitivity of the high-pressure rotor component are all high (more than 50%), the vibration speed response sensitivity of the high-pressure rotor component for the unbalanced load variation at the centrifugal impeller is high (between 15% and 50%, see Table 7), the vibration speed response sensitivity of the high-pressure rotor component for the unbalanced load variation at the secondary disk of the gas turbine is high (between 15% and 50%, see Table 8), the vibration speed response sensitivity of the low-pressure rotor component for the unbalanced load variation at the secondary disk of the power turbine is high (more than 50%, see Table 9), the overall vibration speed response sensitivity due to other unbalanced loads and the vibration speed response sensitivity of the rotor components were low (less than 15%, see table 9 for specific data). As shown in fig. 11, the vibration speed response sensitivity of the whole engine vibration measuring point C4 is high for both the total vibration speed response sensitivity caused by the unbalanced load variation at the primary disk of the compressor (more than 50%, see table 6 for specific data), the vibration speed response sensitivity of the high pressure rotor component caused by the unbalanced load variation at the centrifugal impeller (between 15% and 50%, see table 7 for specific data), the total vibration speed response sensitivity caused by the unbalanced load variation at the secondary disk of the gas turbine (between 15% and 50%) and the vibration speed response sensitivity of the high pressure rotor component (between 15% and 50%, see table 8 for specific data), the total vibration speed response sensitivity caused by the unbalanced load variation at the secondary disk of the power turbine (between 15% and 50%, see table 9 for specific data), the vibration speed response sensitivity of the low pressure rotor component (more than 50%, see table 9) for the total vibration speed response sensitivity due to other unbalanced loads and the vibration speed response sensitivity of the rotor components were low (less than 15%). As shown in FIG. 12, the vibration measuring point C5 of the whole engine has high response sensitivity (between 15% and 50%, see Table 6 for specific data) to the total vibration speed caused by the unbalanced load change at the primary disc of the compressor, the vibration speed response sensitivity of the high-pressure rotor component is very high (more than 50%, see Table 6 for specific data), the vibration speed response sensitivity of the high-pressure rotor component is higher due to the unbalanced load change at the secondary disk of the gas turbine (between 15% and 50%, see the specific data in Table 8), the sensitivity of the vibration speed response caused by the unbalanced load change at the secondary disk of the power turbine and the sensitivity of the vibration speed response of the low-pressure rotor component are high (more than 50 percent, see the specific data in a table 9), the overall vibration speed response sensitivity due to other unbalanced loads and the vibration speed response sensitivity of the rotor components are low (below 15%). As shown in fig. 13, the vibration speed response sensitivity of the whole engine vibration measuring point C6 to the total vibration speed response caused by the unbalanced load change at the primary disc of the compressor and the vibration speed response sensitivity of the high-pressure rotor component are both high (more than 50%, see table 6 for specific data), the sensitivity of the response of the total vibration speed caused by the unbalanced load change at the secondary disk of the gas turbine is higher (between 15% and 50%, see the specific data in the table 8), the sensitivity of the response of the vibration speed of the low-pressure rotor component is high (more than 50 percent, see the specific data in the table 9) for the sensitivity of the response of the vibration speed of the power turbine secondary disk caused by the unbalanced load change, the overall vibration speed response sensitivity due to other unbalanced loads and the vibration speed response sensitivity of the rotor components are low (below 15%).
The sensitivity of the imbalance of the vibration measuring point of the whole engine is calculated by the following formula:
wherein epsilon is the sensitivity of unbalance of vibration measuring points of the whole engine; vOriginal sourceResponding to the vibration speed of the vibration measuring point of the whole engine under the original unbalanced load; vRear endAnd responding to the vibration speed of the vibration measuring point of the whole engine after the unbalanced load changes. Wherein, the imbalance sensitivity obtained by calculating the total vibration speed response of the vibration measuring points of the whole engine in the formula 1 is called as the total vibration speed response sensitivity; the imbalance sensitivity obtained by calculating the vibration speed response of the low/high pressure rotor component of the vibration measuring point of the whole engine is called the vibration speed response sensitivity of the low/high pressure rotor component. The unbalance sensitivity refers to the degree of change of the vibration response (vibration displacement, vibration speed and vibration acceleration) of the rotor under the action of different unbalance loads. The vibration speed response refers to the vibration speed of the vibration system under the action of the excitation load.
TABLE 6 sensitivity of unbalance of vibration measuring points of complete engine under unbalance load change of primary disc of compressor
TABLE 7 sensitivity to unbalance of vibration measuring point of whole engine under unbalance load change of centrifugal impeller
TABLE 8 sensitivity of engine vibration measurement point imbalance under gas turbine secondary disk imbalance load variation
TABLE 9 sensitivity of unbalance of vibration measuring point of complete engine under unbalanced load change of secondary disk of power turbine
Considering that the vibration energy is proportional to the square of the vibration speed response, the vibration measuring point of the whole engine can be selected preferentially through the vibration energy change sensitivity coefficient, and the larger the vibration energy change sensitivity coefficient is, the more sensitive the vibration measuring point of the whole engine is to the whole engine vibration energy change caused by the rotor unbalanced load change. The vibration energy variation sensitivity coefficient is calculated by the following formula:
δ＝ε2 general assembly+ε2 Rotor 2)
Wherein, delta is the vibration energy variation sensitive coefficient; epsilonGeneral assemblyResponse sensitivity of the total vibration speed of the vibration measuring points of the whole engine under the condition of unbalanced load change; epsilonRotorIs the one with a large magnitude of the vibration speed response sensitivity of the high pressure rotor component and the vibration speed response sensitivity of the low pressure rotor component.
Based on the vibration energy change sensitivity coefficient, see table 10, the position of the vibration measuring point of the whole engine corresponding to the vibration frequency response characteristic capable of accurately reflecting the rotor unbalanced load change can be obtained, see table 11. The vibration frequency response characteristics of the vibration measuring points C3 and C4 of the whole engine are better when the vibration measuring points C3 and C4 of the whole engine reflect the unbalance load change of the centrifugal impeller, the vibration frequency response characteristics of the vibration measuring points C3 and C4 of the whole engine reflect the unbalance load change of the secondary disk of the gas turbine are better, and the vibration frequency response characteristics of the vibration measuring points C5 and C6 of the whole engine reflect the unbalance load change of the secondary disk of the power turbine are better.
TABLE 10 vibration energy variation sensitivity coefficient of vibration measuring points of each engine
Table 11 shows the vibration frequency response characteristic of the unbalanced load change of the rotor of the engine complete machine vibration measuring point position
4) And determining the final vibration measuring point of the whole engine according to the condition that the vibration frequency response characteristics of the plurality of alternative vibration measuring points of the whole engine can reflect the vibration characteristics of the rotor.
Finally, engine whole machine vibration measuring points C1, C3 and C5 are selected as positions of the engine whole machine vibration measuring points, and the positions are shown in a table 12, wherein the engine whole machine vibration measuring point C1 can reflect 2-order critical rotating speeds of the high-pressure rotor and the low-pressure rotor, the engine whole machine vibration measuring point C3 can reflect 1-order critical rotating speeds of the high-pressure rotor and the low-pressure rotor unbalanced load changes, and the engine whole machine vibration measuring point C5 can reflect the high-pressure rotor unbalanced load changes.
The whole engine vibration measuring points selected by the method can better reflect the rotor vibration characteristics (critical rotating speed, unbalanced load change and the like), can obtain more rotor vibration characteristic information by using fewer whole engine vibration measuring points, is more sensitive to the rotor vibration characteristic change, and is beneficial to vibration safety monitoring of the engine.
Based on the method for selecting the vibration measuring points of the whole engine, the invention provides a system for selecting the vibration measuring points of the whole engine, which comprises the following steps:
the determining unit is used for determining a selection principle of the whole engine vibration measuring point;
the model unit is used for establishing a finite element model of the whole engine;
and the selecting unit is used for determining the vibration measuring point of the whole engine through the analysis of the vibration frequency response characteristic of the whole engine according to the selection principle of the vibration measuring point of the whole engine and a finite element model of the whole engine.
The model unit is specifically configured to:
simplifying the structural model of the whole engine;
finite element modeling is carried out on the simplified engine whole structure model;
and checking the structural characteristic parameters of the finite element model of the whole engine.
The model unit is specifically configured to:
the shape and the position of a key bearing structure of the engine are kept, so that the accurate simulation of the mechanical property and the vibration property of a bearing system is ensured;
for a reduction gear box or a flame tube of the engine, the structural appearance is kept, and the material density is adjusted to ensure that the quality of corresponding structures is equal; for the bolts, the conduits or the sealing components of the engine, the structure is omitted, and the mass is only added on the connected bearing structure;
deleting local holes, fillets or chamfers on the engine case structure, and simultaneously adjusting the local material density of the case structure to ensure that the quality and the mass center position of the case structure are not changed;
for the blade structure of the engine, in order to ensure that the mass and the rotational inertia of the blade are unchanged, the blade structure is equivalent by adopting a circular ring structure with a simple structure.
The selecting unit is specifically configured to:
preliminarily selecting a plurality of alternative engine whole machine vibration measuring points at the mounting edge of an external casing of the engine;
determining vibration frequency response characteristics of a plurality of alternative engine whole machine vibration measuring points;
and determining a final vibration measuring point of the whole engine according to the vibration frequency response characteristic.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (11)
1. A method for selecting a vibration measuring point of a whole engine is characterized by comprising the following steps:
determining a selection principle of a whole engine vibration measuring point;
establishing a finite element model of the whole engine;
and determining the vibration measuring point of the whole engine through the analysis of the vibration frequency response characteristic of the whole engine according to the selection principle of the vibration measuring point of the whole engine and a finite element model of the whole engine.
2. The method for selecting the whole engine vibration measuring point according to claim 1, wherein the principle of selecting the whole engine vibration measuring point is as follows:
the vibration measuring points of the whole engine are required to be sensitive to the vibration characteristics of the rotor, and are arranged on a radial force transmission path of the rotor, the axial position of which is close to the rotor fulcrum;
the vibration measuring point of the whole engine needs to avoid the influence of local vibration of a casing structure;
in order to ensure the reliability of the installation of the sensor at the vibration measuring point of the whole engine, the vibration measuring point of the whole engine is selected at the installation edge of the casing or the position of the stable sensor.
3. The method for selecting the vibration measuring points of the whole engine according to claim 2, wherein the sensor is an acceleration sensor, a speed sensor or a displacement sensor.
4. The method for selecting the vibration measuring points of the whole engine as claimed in claim 1, wherein the establishing of the finite element model of the whole engine comprises the following substeps:
simplifying the structural model of the whole engine;
finite element modeling is carried out on the simplified engine whole structure model;
and checking the structural characteristic parameters of the finite element model of the whole engine.
5. The method for selecting the vibration measuring points of the whole engine as claimed in claim 4, wherein the checking comprises performing error analysis on the mass and the centroid position of a finite element model of the whole engine and a finite element model of a stator component, and performing error analysis on the mass and the rotational inertia of the finite element model of the rotor component.
6. The method for selecting the vibration measuring points of the whole engine as claimed in claim 4, wherein the steps of simplifying the structural model of the whole engine are as follows:
the shape and the position of a key bearing structure of the engine are kept, so that the accurate simulation of the mechanical property and the vibration property of a bearing system is ensured;
for a reduction gear box or a flame tube of the engine, the structural appearance is kept, and the material density is adjusted to ensure that the quality of corresponding structures is equal; for the bolts, the conduits or the sealing components of the engine, the structure is omitted, and the mass is only added on the connected bearing structure;
deleting local holes, fillets or chamfers on the engine case structure, and simultaneously adjusting the local material density of the case structure to ensure that the quality and the mass center position of the case structure are not changed;
for the blade structure of the engine, in order to ensure that the mass and the rotational inertia of the blade are unchanged, the blade structure is equivalent by adopting a circular ring structure with a simple structure.
7. The method for selecting the whole engine vibration measuring point according to claim 1, wherein the step of determining the whole engine vibration measuring point comprises the following substeps:
preliminarily selecting a plurality of alternative engine whole machine vibration measuring points at the mounting edge of an external casing of the engine;
determining vibration frequency response characteristics of a plurality of alternative engine whole machine vibration measuring points;
and determining a final vibration measuring point of the whole engine according to the vibration frequency response characteristic.
8. The utility model provides a system is selected to engine complete machine vibration measurement station which characterized in that includes:
the determining unit is used for determining a selection principle of the whole engine vibration measuring point;
the model unit is used for establishing a finite element model of the whole engine;
and the selecting unit is used for determining the vibration measuring point of the whole engine through the analysis of the vibration frequency response characteristic of the whole engine according to the selection principle of the vibration measuring point of the whole engine and a finite element model of the whole engine.
9. The system for selecting the vibration measuring points of the whole engine as claimed in claim 8, wherein the model unit is specifically configured to:
simplifying the structural model of the whole engine;
finite element modeling is carried out on the simplified engine whole structure model;
and checking the structural characteristic parameters of the finite element model of the whole engine.
10. The system for selecting the vibration measuring points of the whole engine as claimed in claim 9, wherein the model unit is specifically configured to:
the shape and the position of a key bearing structure of the engine are kept, so that the accurate simulation of the mechanical property and the vibration property of a bearing system is ensured;
for a reduction gear box or a flame tube of the engine, the structural appearance is kept, and the material density is adjusted to ensure that the quality of corresponding structures is equal; for the bolts, the conduits or the sealing components of the engine, the structure is omitted, and the mass is only added on the connected bearing structure;
deleting local holes, fillets or chamfers on the engine case structure, and simultaneously adjusting the local material density of the case structure to ensure that the quality and the mass center position of the case structure are not changed;
for the blade structure of the engine, in order to ensure that the mass and the rotational inertia of the blade are unchanged, the blade structure is equivalent by adopting a circular ring structure with a simple structure.
11. The system for selecting the vibration measurement points of the whole engine according to claim 8, wherein the selection unit is specifically configured to:
preliminarily selecting a plurality of alternative engine whole machine vibration measuring points at the mounting edge of an external casing of the engine;
determining vibration frequency response characteristics of a plurality of alternative engine whole machine vibration measuring points;
and determining a final vibration measuring point of the whole engine according to the vibration frequency response characteristic.
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| CN202111446557.4A CN114117862A (en) | 2021-11-30 | 2021-11-30 | Engine whole machine vibration measuring point selection method and system |
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| CN202111446557.4A CN114117862A (en) | 2021-11-30 | 2021-11-30 | Engine whole machine vibration measuring point selection method and system |
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