CN115329254A - Method for evaluating influence of vertical condensate pump axial line inclination on vibration - Google Patents

Method for evaluating influence of vertical condensate pump axial line inclination on vibration Download PDF

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CN115329254A
CN115329254A CN202210705976.3A CN202210705976A CN115329254A CN 115329254 A CN115329254 A CN 115329254A CN 202210705976 A CN202210705976 A CN 202210705976A CN 115329254 A CN115329254 A CN 115329254A
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vibration
motor
inclination
rotating shaft
influence
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周瑜
李敬豪
李俊
黄承实
王丁丁
陈悦
施昊
陈左亮
岳喜全
万京东
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NANJING ELECTRIC POWER PLANT OF DATANG GROUP
China Datang Corp Science and Technology Research Institute Co Ltd
Datang Boiler Pressure Vessel Examination Center Co Ltd
East China Electric Power Test Institute of China Datang Corp Science and Technology Research Institute Co Ltd
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NANJING ELECTRIC POWER PLANT OF DATANG GROUP
China Datang Corp Science and Technology Research Institute Co Ltd
Datang Boiler Pressure Vessel Examination Center Co Ltd
East China Electric Power Test Institute of China Datang Corp Science and Technology Research Institute Co Ltd
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Abstract

A method for evaluating the influence of vertical condensate pump axial inclination on vibration belongs to the technical field of thermal power generation and solves the problem of how to evaluate the influence of vertical condensate pump axial inclination on vibration; measuring the influence coefficient of the exciting force on the vibration under different rotation frequencies in the acceleration process through a counterweight test, constructing an identification equation set by using the vibration data and the influence coefficient in the acceleration process, and solving the unbalanced eccentricity and the rotating shaft inclined exciting force by adopting a least square method; evaluating the accuracy of the recognition model according to the comparison of the vibration in the inversely calculated acceleration process and the vibration in the actually measured acceleration process; evaluating the influence of the vertical condensate pump axial line inclination on vibration according to the identified rotating shaft inclination exciting force and influence coefficient; different from the test analysis in the traditional shutdown state, the method can be used for evaluation under the operation condition, solves the problem that the influence of the inclination of the vertical condensate pump axis on the vibration is difficult to evaluate in the operation state, and is used for guiding the fault diagnosis of the vertical condensate pump.

Description

Method for evaluating influence of vertical condensate pump axial line inclination on vibration
Technical Field
The invention belongs to the technical field of thermal power generation, and relates to a method for evaluating the influence of vertical condensate pump axial line inclination on vibration.
Background
As shown in fig. 7, the power plant condensate pump is arranged vertically, and the motor for driving the condensate pump is positioned at the top end of the condensate pump. Taking a condensing pump matched with a 600MW steam turbine as an example, the weight of the pump is about 15t, the weight of a top end motor is about 10t, and the total length of an axis is about 15 meters. The pump seat is provided with a guide shoe and thrust shoe type bearing combination device to bear the radial force and the axial thrust of the rotor, and the pump is internally provided with a plurality of water lubrication rubber bearings to bear the radial force of the rotor. Such systems have long and thin shafts and light weight. If the parallelism of the bottom plate is not positive, after the thrust head is installed on the shafting, the working surface is not vertical to the central line of the shafting, and the axial line generates conical vortex motion around the vertical central line after the machine is started. The conical whirl of the axis causes the unit to vibrate, and is reflected by the top end of the motor and the lower end of the condensate pump. The vibration of the coagulation pump is influenced by more factors, such as: imbalance, misalignment, insufficient foundation stiffness, resonance, pipeline limitation and the like, and the axis inclination is only one of the reasons.
After the coagulation pump has vibration failure, the influence of the axis inclination on the vibration needs to be analyzed and evaluated according to the vibration characteristics. The methods adopted in the prior art mainly comprise: 1) And (4) a dial indicator method. Under the shutdown state, erect the percentage table in the exposure shaft section position between motor and thrust collar, the dish moves the rotor, according to percentage table reading change condition, according to the biggest of percentage table and minimum reading difference, can test out shaft section department shake. 2) And (4) a thrust collar levelness testing method. And in a shutdown state, erecting a level gauge at the position of the thrust collar, testing the levelness of the thrust collar, and judging the inclination condition of the shaft according to the levelness. The poorer the levelness, the greater the inclination of the shaft. 3) After the fact, tui Li. During equipment maintenance, the guide shoes are opened for inspection, and the axial line inclination condition is analyzed according to the abrasion condition of each level of guide shoes from top to bottom. 4) Vibration fault diagnosis. The factors influencing the vibration of the coagulation pump are more, including: unbalance, misalignment, insufficient base rigidity, resonance, pipeline limitation, axis inclination and the like. After the vibration problem appears, according to unit vibration phenomenon, if: spectrum, waveform, phase and other characteristics, and diagnosing the axial line inclination condition. Alternatively, after removing other causes of failure such as imbalance, the remaining is the axis tilt.
The disadvantages of the methods employed in the prior art are as follows: 1) The dial indicator method and the thrust collar levelness testing method can be carried out only in a shutdown state, the measured data can only reflect the shutdown state, the axial line inclination and the shutdown state in the running state have a large difference, and the data measured by the 2 methods are only the axial section inclination condition and cannot be used for evaluating the influence degree of the axial line inclination on the vibration in the running state. 2) The after-the-fact reasoning method needs to disassemble the pump and the motor, can only be used for after-the-fact analysis, and cannot meet the fault analysis requirement in the operating state. 3) The vibration characteristics and unbalance faults caused by the inclination of the axis are similar, for example: the main power frequency component in the frequency spectrum, the waveform is similar to sine wave and the like, the axis inclination state and the influence on the vibration are difficult to evaluate according to the measured vibration characteristics at present, and after various similar faults except the conical vortex motion are eliminated, the fault can be considered to be caused by the axis inclination, so that a large amount of tests need to be carried out in the vibration fault diagnosis method, and the workload is huge.
Disclosure of Invention
The invention aims to solve the technical problem of how to evaluate the influence of the axial inclination of a vertical condensate pump on vibration so as to guide the development of the vibration fault diagnosis work of the condensate pump.
The invention solves the technical problems through the following technical scheme:
a method for evaluating the influence of vertical coagulation pump axial inclination on vibration comprises the following steps:
s1, establishing a calculation model of total vibration displacement response excited by unbalanced excitation force and rotating shaft inclined excitation force under rotating frequency;
s2, selecting a plurality of rotation frequency points, constructing an identification equation set according to motor vibration data under different rotation frequencies, and solving the equation set by adopting a least square method, so as to identify an unbalanced eccentric vector and a rotating shaft inclination vector;
s3, inversely calculating a curve of the vibration along with the rotating speed in the acceleration process according to the identified unbalanced eccentric vector and the identified rotating shaft inclination vector, and analyzing the accuracy of the identification model according to the contact ratio of the vibration curve in the actual measurement acceleration process and the inversely calculated vibration curve in the acceleration process;
and S4, evaluating the influence of the axis inclination on the vibration according to the proportion of the vibration displacement response excited by the inclination exciting force of the rotating shaft in the total vibration displacement response.
According to the method for evaluating the influence of the vertical coagulation pump axial line inclination on vibration, the influence coefficient of the excitation force on the vibration under different rotation frequencies in the acceleration process is measured through a balance weight test, an identification equation set is constructed by the vibration data and the influence coefficient in the acceleration process, and then the unbalanced eccentricity and the rotating shaft inclination excitation force are solved by adopting a least square method; evaluating the accuracy of the recognition model according to the comparison of the vibration in the inversely calculated acceleration process and the vibration in the actually measured acceleration process; evaluating the influence of the vertical condensate pump axial line inclination on vibration according to the identified rotating shaft inclination exciting force and influence coefficient; different from the test analysis in the traditional shutdown state, the method can be used for the evaluation under the operation condition, solves the problem that the influence of the vertical condensate pump axial line inclination in the operation state on the vibration is difficult to evaluate, and is used for guiding the fault diagnosis of the vertical condensate pump.
Further, the specific method for establishing the calculation model of the total vibration displacement response excited by the unbalanced excitation force and the rotating shaft inclined excitation force under the rotating frequency in step S1 is as follows:
s11, considering the structural characteristics of the motor, simplifying the motor into a single-degree-of-freedom system which consists of mass, springs and damping, wherein the motor acts on an exciting force F from a pump shaft and a motor rotor, and the exciting force F is an unbalanced exciting force F of the rotor u And the inclined exciting force F of the rotating shaft r The calculation formula of the two parts is as follows:
Figure BDA0003706174600000031
wherein u is the eccentric moment of the unbalanced excitation force of the rotor; omega is the rotation frequency; gamma ray 1 Phase angle of unbalanced excitation force of the rotor; r is the amplitude of the tilting exciting force of the rotating shaft; gamma ray 2 Is the phase angle of the inclined exciting force of the rotating shaft;
s12, known by the vibration theory, the motor dynamic equation is as follows:
Figure BDA0003706174600000032
wherein m is the mass of the motor, k is the rigidity coefficient of the motor, c is the damping coefficient of the motor, x,
Figure BDA0003706174600000033
Figure BDA0003706174600000034
Respectively representing the vibration displacement response, the speed response and the acceleration response of the motor;
s12, the vibration displacement response x (t) is the sum of the vibration displacements excited by the unbalanced excitation force of the rotor and the inclined excitation force of the rotating shaft, and the sum is as follows:
Figure BDA0003706174600000035
wherein A is u (ω),A r (omega) are respectively the amplitude of vibration displacement response excited by the unbalanced excitation force and the rotating shaft inclined excitation force under the rotating frequency omega,
Figure BDA0003706174600000036
respectively the phases of vibration displacement response excited by unbalanced excitation force and rotating shaft inclined excitation force under the rotating frequency omega;
the calculation formula is as follows:
Figure BDA0003706174600000037
wherein the content of the first and second substances,
Figure BDA0003706174600000038
ξ＝c/(2mω n )。
the abbreviation is:
Figure BDA0003706174600000039
wherein α (ω) is an influence coefficient of an exciting force on vibration at a rotation frequency ω, that is:
Figure BDA0003706174600000041
s14, the unbalanced excitation force, the rotating shaft inclined excitation force, the influence coefficient and the vibration displacement response all comprise amplitude values and phases, and are uniformly expressed in a complex form:
Figure BDA0003706174600000042
wherein, the arrow mark above the variable represents that the variable is complex;
s15, total vibration response
Figure BDA0003706174600000043
The complex number is represented as:
Figure BDA0003706174600000044
wherein the content of the first and second substances,
Figure BDA0003706174600000045
for the vibration displacement response excited by the unbalanced excitation force at the rotation frequency omega,
Figure BDA0003706174600000046
the vibration displacement response excited by the tilt exciting force of the lower rotating shaft at the rotation frequency omega,
Figure BDA0003706174600000047
respectively an unbalanced eccentricity vector and a rotation axis inclination vector.
Further, the influence coefficient
Figure BDA0003706174600000048
The measurement method of (2) is as follows:
1) Arranging a vibration sensor at the top end of the motor along the horizontal direction, and testing the vibration of the top end of the motor;
2) Starting the motor to a rated rotating speed, testing the vibration of the motor at the rated rotating speed by using a vibration sensor, and recording the vibration amplitude and the phase as A respectively 0 And
Figure BDA0003706174600000049
expressed in complex form as:
Figure BDA00037061746000000410
3) The motor shaft is additionally provided with a balancing weight, the product of the weight of the balancing weight and the weighted radius is e, and the installation angle is beta, so that the generated unbalanced excitation force of the balancing weight
Figure BDA00037061746000000411
Expressed in complex form as:
Figure BDA00037061746000000412
4) Testing vibration of the motor after adding the balance weight by using a vibration sensor, and recording the amplitude as A 1 In a phase of
Figure BDA00037061746000000413
Expressed in complex form as:
Figure BDA0003706174600000051
5) Coefficient of influence of exciting force on vibration
Figure BDA0003706174600000052
The calculation formula of (a) is as follows:
Figure BDA0003706174600000053
further, the method for selecting a plurality of rotation frequency points in step S2, constructing an identification equation set according to the motor vibration data at different rotation frequencies, and solving the equation set by using a least square method, thereby identifying the unbalanced eccentric vector and the rotation axis tilt vector, includes:
selecting n frequency points omega to be analyzed 1 ,ω 2 ,…,ω n According to the motor vibration data under different rotation frequencies, an identification equation set is constructed as follows:
Figure BDA0003706174600000054
solving the equation (13) by using a least square method so as to identify an unbalanced eccentricity vector and a rotating shaft inclination vector
Figure BDA0003706174600000055
The invention has the advantages that:
according to the method for evaluating the influence of the vertical coagulation pump axial line inclination on vibration, the influence coefficient of the excitation force on the vibration under different rotation frequencies in the acceleration process is measured through a balance weight test, an identification equation set is constructed by the vibration data and the influence coefficient in the acceleration process, and then the unbalanced eccentricity and the rotating shaft inclination excitation force are solved by adopting a least square method; evaluating the accuracy of the recognition model according to the comparison of the vibration in the raising speed process and the vibration in the actually measured raising speed process; evaluating the influence of the vertical condensate pump axial line inclination on vibration according to the identified rotating shaft inclination exciting force and influence coefficient; different from the test analysis in the traditional shutdown state, the method can be used for evaluation under the operation condition, solves the problem that the influence of the inclination of the vertical condensate pump axis on the vibration is difficult to evaluate in the operation state, and is used for guiding the fault diagnosis of the vertical condensate pump.
Drawings
FIG. 1 is a flow chart of a method for assessing the effect of vertical condensate axis tilt on vibration in accordance with an embodiment of the present invention;
FIG. 2 is a simplified model of a condensate pump motor dynamics analysis according to an embodiment of the present invention;
FIG. 3 is a curve showing the variation of the amplitude and phase of the influence coefficient with the rotation speed in the accelerating process, obtained by the counterweight test according to the embodiment of the present invention;
FIG. 4 is a curve showing the variation of the actually measured vibration amplitude and phase with the rotation speed during the acceleration process according to the embodiment of the present invention;
FIG. 5 is a comparison of the curves of the variation of the vibration amplitude and phase with the rotation speed, which are actually measured and inversely calculated in the acceleration process according to the embodiment of the present invention;
FIG. 6 is a graph showing the variation of vibration amplitude with rotation speed caused by unbalanced excitation force and rotation shaft inclination in the acceleration process according to the embodiment of the present invention;
FIG. 7 illustrates the vertical condensate pump axis tilt and its induced conical whirl.
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 embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. 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 technical scheme of the invention is further described by combining the drawings and the specific embodiments in the specification:
example one
As shown in fig. 1, a method for evaluating the influence of vertical condensate pump axis inclination on vibration includes the following steps:
1. establishing a calculation model of total vibration displacement response excited by unbalanced excitation force and rotating shaft inclined excitation force under the rotating frequency;
as shown in figure 2, the motor is simplified into a single-degree-of-freedom system by considering the structural characteristics of the motor, the system consists of mass, spring and damping, the motor is acted with exciting force F from a pump shaft and a motor rotor, and the exciting force F is formed by unbalanced rotor exciting force F u And the inclined exciting force F of the rotating shaft r The calculation formula of the two parts is as follows:
Figure BDA0003706174600000061
wherein u is rotor unevennessThe eccentric moment of the excitation force is balanced, and the unit is g.m; omega is rotation frequency, and the unit is rad/s; gamma ray 1 Phase angle of unbalanced excitation force of the rotor; r is the amplitude of the inclined exciting force of the rotating shaft, and the unit is N; gamma ray 2 Is the phase angle of the inclined exciting force of the rotating shaft.
From vibration theory, the motor dynamics equation can be written as:
Figure BDA0003706174600000062
wherein m is the mass of the motor, k is the rigidity coefficient of the motor, c is the damping coefficient of the motor, x,
Figure BDA0003706174600000071
Figure BDA0003706174600000072
Respectively, the motor vibration displacement response, the speed response and the acceleration response.
The vibration displacement response x (t) is the sum of vibration displacements excited by the unbalanced excitation force of the rotor and the inclined excitation force of the rotating shaft, and can be written as follows:
Figure BDA0003706174600000073
wherein A is u (ω),A r (omega) are respectively the amplitude of vibration displacement response excited by unbalanced excitation force and rotating shaft inclined excitation force under the rotating frequency omega,
Figure BDA0003706174600000074
the phases of vibration displacement response excited by the unbalanced excitation force and the rotating shaft inclined excitation force under the rotating frequency omega are respectively.
The calculation formula is as follows:
Figure BDA0003706174600000075
wherein the content of the first and second substances,
Figure BDA0003706174600000076
ξ＝c/(2mω n )。
can be abbreviated as:
Figure BDA0003706174600000077
wherein α (ω) is an influence coefficient of an exciting force on vibration at a rotation frequency ω, that is:
Figure BDA0003706174600000078
unbalanced excitation force, pivot slope excitation force, influence coefficient and vibration displacement response all contain amplitude and phase place, and the unity is represented by the complex number form:
Figure BDA0003706174600000081
wherein, the arrow mark above the variable represents that the variable is complex;
responsive to total vibration
Figure BDA0003706174600000082
The complex number is represented as:
Figure BDA0003706174600000083
wherein the content of the first and second substances,
Figure BDA0003706174600000084
for the vibration displacement response excited by the unbalanced excitation force at the rotation frequency omega,
Figure BDA0003706174600000085
the vibration displacement response excited by the tilt exciting force of the lower rotating shaft at the rotation frequency omega,
Figure BDA0003706174600000086
respectively an unbalanced eccentricity vector and a rotation axis inclination vector.
Said coefficient of influence
Figure BDA0003706174600000087
The measurement method of (2) is as follows:
(1) Arranging a vibration sensor at the top end of the motor along the horizontal direction, and testing the vibration of the top end of the motor;
(2) Starting the motor to a rated rotating speed, testing the vibration of the motor at the rated rotating speed by using a vibration sensor, and recording the vibration amplitude and the phase as A respectively 0 And
Figure BDA0003706174600000088
expressed in complex form as:
Figure BDA0003706174600000089
(3) The motor shaft is additionally provided with a balancing weight, the product of the weight of the balancing weight and the weighted radius is e, and the installation angle is beta, so that the generated unbalanced excitation force of the balancing weight
Figure BDA00037061746000000810
Expressed in complex form as:
Figure BDA00037061746000000811
(4) Testing vibration of the motor after adding the balance weight by using a vibration sensor, and recording the amplitude as A 1 In a phase of
Figure BDA00037061746000000812
Expressed in complex form as:
Figure BDA00037061746000000813
(5) Coefficient of influence of exciting force on vibration
Figure BDA00037061746000000814
The calculation formula of (a) is as follows:
Figure BDA00037061746000000815
fig. 3 shows the variation curve of the amplitude and phase of the influence coefficient with the rotating speed in the speed increasing process obtained by the counterweight test.
2. Selecting a plurality of rotation frequency points, constructing an identification equation set according to motor vibration data under different rotation frequencies, and solving the equation set by adopting a least square method so as to identify an unbalanced eccentric vector and a rotating shaft inclination vector;
selecting n frequency points omega to be analyzed 1 ,ω 2 ,…,ω n According to the motor vibration data under different rotation frequencies, an identification equation set is constructed as follows:
Figure BDA0003706174600000091
solving equation (16) by using least square method, thereby identifying unbalanced eccentricity vector and rotating shaft inclination vector
Figure BDA0003706174600000095
。
Fig. 4 shows a set of curves of measured vibration amplitude and phase with rotation speed during acceleration.
3. Inversely calculating a curve of the vibration along with the change of the rotating speed in the acceleration process according to the identified unbalanced eccentric vector and the rotating shaft inclination vector, and analyzing the accuracy of the identification model according to the actually measured curve of the vibration change in the acceleration process and the inversely calculated coincidence degree of the curve of the vibration change in the acceleration process;
from the identified imbalance eccentricity vector and the rotation axis inclination vector
Figure BDA0003706174600000092
And (4) substituting the curve into a formula (8), calculating a curve of the vibration along with the rotating speed in the acceleration process in a reverse mode, and analyzing the accuracy of the identification model according to the contact ratio of the vibration curve in the actual measurement acceleration process and the vibration curve in the reverse calculated acceleration process. FIG. 5 shows a set of measured and back-calculated vibration amplitude and phase versus speed curves during acceleration.
4. And evaluating the influence of the axis inclination on the vibration according to the proportion of the vibration displacement response excited by the inclination exciting force of the rotating shaft in the total vibration displacement response.
The vibration caused by unbalanced exciting force and the vibration caused by the inclined exciting force of the rotating shaft in the motor vibration in the speed raising process are respectively as follows:
Figure BDA0003706174600000093
according to
Figure BDA0003706174600000094
And its proportion in the total vibration, and the influence of the axis inclination on the vibration is evaluated. FIG. 6 shows a set of curves of vibration amplitude induced by unbalanced excitation force and shaft tilt during ramp-up as a function of rotational speed.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; 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 (4)

1. A method for evaluating the influence of vertical coagulation pump axial inclination on vibration is characterized by comprising the following steps:
s1, establishing a calculation model of total vibration displacement response excited by unbalanced excitation force and rotating shaft inclined excitation force under a rotating frequency;
s2, selecting a plurality of rotation frequency points, constructing an identification equation set according to motor vibration data under different rotation frequencies, and solving the equation set by adopting a least square method, so as to identify an unbalanced eccentric vector and a rotating shaft inclination vector;
s3, inversely calculating a curve of the vibration along with the rotating speed in the acceleration process according to the identified unbalanced eccentric vector and the identified rotating shaft inclination vector, and analyzing the accuracy of the identification model according to the contact ratio of the vibration curve in the actual measurement acceleration process and the inversely calculated vibration curve in the acceleration process;
and S4, evaluating the influence of the axis inclination on the vibration according to the proportion of the vibration displacement response excited by the inclination exciting force of the rotating shaft in the total vibration displacement response.
2. The method for evaluating the influence of the vertical condensate pump axial line inclination on the vibration according to claim 1, wherein the specific method for establishing the calculation model of the total vibration displacement response excited by the unbalance excitation force and the rotating shaft inclination excitation force under the rotating frequency in the step S1 is as follows:
s11, considering the structural characteristics of the motor, simplifying the motor into a single-degree-of-freedom system which consists of mass, springs and damping, wherein the motor acts on an exciting force F from a pump shaft and a motor rotor, and the exciting force F is an unbalanced exciting force F of the rotor u And the inclined exciting force F of the rotating shaft r The calculation formula of the two parts is as follows:
Figure FDA0003706174590000011
wherein u is the eccentric moment of the unbalanced excitation force of the rotor; omega is the rotation frequency; gamma ray 1 Phase angle of unbalanced excitation force of the rotor; r is the amplitude of the tilting exciting force of the rotating shaft; gamma ray 2 Is the phase angle of the inclined exciting force of the rotating shaft;
s12, known by the vibration theory, the motor dynamic equation is as follows:
Figure FDA0003706174590000012
wherein m is the mass of the motor, k is the rigidity coefficient of the motor, c is the damping coefficient of the motor, x,
Figure FDA0003706174590000013
Figure FDA0003706174590000014
Respectively representing motor vibration displacement response, speed response and acceleration response;
s12, the vibration displacement response x (t) is the sum of vibration displacements excited by the unbalanced excitation force of the rotor and the inclined excitation force of the rotating shaft, and the sum is as follows:
Figure FDA0003706174590000015
wherein, A u (ω),A r (omega) are respectively the amplitude of vibration displacement response excited by the unbalanced excitation force and the rotating shaft inclined excitation force under the rotating frequency omega,
Figure FDA0003706174590000021
respectively are the phases of vibration displacement response excited by the unbalanced excitation force and the rotating shaft inclined excitation force under the rotating frequency omega;
the calculation formula is as follows:
Figure FDA0003706174590000022
wherein, the first and the second end of the pipe are connected with each other,
Figure FDA0003706174590000023
ξ＝c/(2mω n )。
the abbreviation is:
Figure FDA0003706174590000024
wherein α (ω) is an influence coefficient of an exciting force on vibration at a rotation frequency ω, that is:
Figure FDA0003706174590000025
s14, the unbalanced excitation force, the rotating shaft inclined excitation force, the influence coefficient and the vibration displacement response all comprise amplitude values and phases, and are uniformly expressed in a complex form:
Figure FDA0003706174590000026
wherein, the arrow mark above the variable represents that the variable is complex;
s15, total vibration response
Figure FDA0003706174590000027
The complex number is represented as:
Figure FDA0003706174590000031
wherein the content of the first and second substances,
Figure FDA0003706174590000032
for the vibration displacement response excited by the unbalanced excitation force at the rotation frequency omega,
Figure FDA0003706174590000033
the vibration displacement response excited by the lower shaft inclination exciting force at the rotation frequency omega,
Figure FDA0003706174590000034
respectively unbalanced eccentricity vector and rotation axis inclination vector。
3. The method of claim 2, wherein the influence coefficient is an influence of vertical condensate pump axis tilt on vibration
Figure FDA0003706174590000035
The measurement method of (2) is as follows:
1) Arranging a vibration sensor at the top end of the motor along the horizontal direction, and testing the vibration of the top end of the motor;
2) Starting the motor to a rated rotating speed, testing the vibration of the motor at the rated rotating speed by using a vibration sensor, and recording the vibration amplitude and the phase as A respectively 0 And
Figure FDA0003706174590000036
expressed in complex form as:
Figure FDA0003706174590000037
3) The motor shaft is additionally provided with a balancing weight, the product of the weight of the balancing weight and the weighted radius is e, and the installation angle is beta, so that the generated unbalanced excitation force of the balancing weight
Figure FDA0003706174590000038
Expressed in complex form as:
Figure FDA0003706174590000039
4) Testing vibration of the motor after adding the balance weight by using a vibration sensor, and recording the amplitude as A 1 In a phase of
Figure FDA00037061745900000310
Expressed in complex form as:
Figure FDA00037061745900000311
5) Coefficient of influence of exciting force on vibration
Figure FDA00037061745900000312
The calculation formula of (a) is as follows:
Figure FDA00037061745900000313
4. the method for evaluating the influence of the vertical condensate pump axial line inclination on the vibration according to claim 2, wherein the method for selecting a plurality of rotation frequency points, constructing an identification equation set according to motor vibration data under different rotation frequencies and solving the equation set by using a least square method so as to identify the unbalanced eccentric vector and the rotating shaft inclination vector comprises the following steps of:
selecting n frequency points omega to be analyzed 1 ,ω 2 ,…,ω n According to the motor vibration data under different rotation frequencies, an identification equation set is constructed as follows:
Figure FDA0003706174590000041
solving the equation (13) by using a least square method so as to identify an unbalanced eccentricity vector and a rotating shaft inclination vector
Figure FDA0003706174590000042
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