CN101929917B - Fault diagnosis method for rotary machine - Google Patents

Abstract

The invention relates to a fault diagnosis method for a rotary machine, comprising the following steps: acquiring original vibration signals of two perpendicular channels on a vibration measurement section, and carrying out anti-aliasing filtering, low pass filtering and the like on collected signals; removing unnecessary interference noise signals, adopting complex FFT conversion to calculate a primary vibration vector a and a secondary vibration vector b; further calculating relevant numerical values of a vector area and a vector vibration ratio and obtaining graphs of the vector area and the vector vibration ratio relative to various variables; and utilizing the vector area to express the vibration strength and direction of a measuring point under single frequency, and utilizing the vector vibration ratio to express eccentricity size, flat degree and forward and reverse precessional motion of a vector ellipse. The method has the advantage of good effect in diagnosing the steady-state faults and instantaneous faults of the rotary machine; and the vector area graph and the vector vibration ratio are combined to diagnose the faults, thus the erroneous judgment generated by only utilizing the vector area is avoided, the diagnosis accuracy is enhanced, and the diagnosis efficiency and precision are improved.

Description

A kind of method for diagnosing faults of rotating machinery

Technical field

Patent of the present invention belongs to the mechanical fault diagnosis field, is specifically related to rotary machinery fault diagnosis and control field.

Background technology

General orthogonal two probes in same cross section that adopt of the detection of rotating machinery are accomplished; But because the whirling motion characteristic of rotor; The detected information of arbitrary probe all can not reflect the actual state of unit operation on spectrum value and structure; Difference is very big under many circumstances, can directly influence diagnostic result, causes erroneous judgement.In order to reflect the vibrational state of rotor objectively; The erroneous judgement of avoiding so causing; Many scholars and researchist have done a large amount of research and application work; Comprising domestic holographic spectral analysis technology, vow spectral analysis technology and external full spectral analysis technology entirely; These analytical approachs have obtained great success with technology in practical engineering application, but also find the place of some shortcomings, Quan shown in Fig. 1-a～Fig. 1-c, be followed successively by holographic spectrum, vow spectrum and compose the graph of a relation that each component changes with octave entirely.Holographic spectral analysis technology be under each frequency multiplication with the oval state that vibrates represented, but, directly adopt the oval expressed intact of representing to be difficult to, so its figure spectral resolution is low owing to differ more for a long time at each harmonic amplitude.The full spectral analysis technology of vowing is under each frequency multiplication, to represent the intensity vibrated with oval major semi-axis size, and the figure spectral resolution is high, but is difficult to distinguish the equal and eccentricity anisochrouous vibrational state of major semi-axis.Full spectral analysis technology is to show on positive and negative frequency axis in oval two the positive radius of circle sizes of decomposing of following orbit of shaft center of each frequency multiplication; Amplitude size through on the positive and negative frequency axis under the two same harmonic wave of comparison is judged the precession direction; The figure spectral resolution is high; But also need use the amplitude phase Calais on the positive and negative frequency axis of same harmonic wave to confirm owing to judge each frequency lower rotor part oscillation intensity size,, be difficult to provide the presentation of bulk strength structure so the expression of intensity is carried out indirectly.

Summary of the invention

The object of the present invention is to provide a kind of method for diagnosing faults of rotating machinery, can remedy the incomplete and not high shortcoming of resolution of existing analytical approach information representation, improve the accuracy of judging.

For realizing above-mentioned purpose, the technical scheme of the method for diagnosing faults of rotating machinery provided by the invention is following: a kind of stable state method for diagnosing faults of rotating machinery, and the step of this method is following:

(1) arranges two mutually perpendicular displacement transducers in the rotor cross section; Gather the rotor oscillation signal: in vertical plane; The X transducer arrangements in the horizontal direction; Y transducer arrangements in the vertical direction, consistent with the rotor speed direction to the direction of Y by X, employing waits the tach signal collection and carries out integer-period sampled synchronously with key signal;

(2) signal of gathering is carried out anti-aliasing filtering, LPF, remove unnecessary interfering noise signal;

(3) adopt multiple FFT conversion, lead arrow

calculating of shaking of arrows that shake

, pair;

(4) calculate the vector area

and the vibration sagittal ratio

of vowing ellipse: vector area is that the orbit of shaft center that contains the precession direction is vowed oval area; Express the measuring point oscillation intensity size under the single-frequency with the size of vector area value, the positive and negative precession of the positive and negative expression rotor of vector area value: promptly the size of

is represented the oscillation intensity state under this frequency; When

; Rotor is positive precession; When

, rotor is anti-precession; is used to explain the X axis vibration absolute value and the Y axis vibration absolute value merges preceding magnitude relationship; Compare the suffered exciting force size of rotor both direction:

=1 expression X axle and Y axis vibration absolute value equate that =

expression X axis vibration absolute value and Y axis vibration absolute value differ infinity;

(5) vector area and vibration sagittal ratio the graph of a relation that draws with respect to frequency multiplication or other variable;

(6) in the stable state fault diagnosis; Vector area , vibration sagittal ratio

and graph of a relation are analyzed: the characteristics of variables under the first read fortune fault characteristic frequency together; Analyze possible fault type; The size of vibration sagittal ratio and axial vibration and amplitude are differentiated the common particular type that combines to confirm fault under the corresponding fault characteristic frequency of basis again; When handling transient process information, in conjunction with the method for expressing of Bode diagram, the instantaneous graph of a relation of the vector area of drawing, pairing frequency of vector area value maximum and tachometer value are the resonant frequency and the critical rotary speed value of rotor-support-foundation system in the analysis collection of illustrative plates.

The shake computing method of arrow, vibration sagittal ratio and vector area of the main arrow that shakes, pair are following:

（1）

In the formula; ,

represent the main arrow that shakes, the pair arrow that shakes respectively; ε representes vibration sagittal ratio,

represent vector area.

Patent of the present invention has following function and characteristics:

1. this method has been used for reference the advantage of holographic spectrum with the oval vibrational state of describing, and has been integrated into ellipse and has quantized; Absorb in the full arrow spectrum major semi-axis and represented the advantage that oscillation intensity quantizes, be integrated into the vibration performance of different eccentricities; Utilize full spectrum to quantize and described the advantage that two positive radius of circles are judged the precession direction, be integrated into the characteristic that to distinguish vibrational state.

2. utilize vector area spectrogram and vibration sagittal ratio to combine fault is judged, the erroneous judgement phenomenon that has produced when having avoided independent use vector area has strengthened the accuracy of diagnosis.

3. than additive method, because the characteristic that vector area itself is had makes this method have characteristics highly sensitive, good stability.

Description of drawings

Fig. 1-a is the synoptic diagram of holographic spectrum;

Fig. 1-b is full synoptic diagram of vowing spectrum;

Fig. 1-c is the synoptic diagram of full spectrum;

Fig. 2-a is that vector area is vowed the curve map that changes with main shaking;

To be vector area with pair shake Fig. 2-b vows the curve map that changes;

Fig. 2-c is the curve map that vector area changes with octave;

Full Fig. 3-a vows in the stable state fault diagnosis that the spectral method master shakes to vow the curve map that changes with octave;

Full Fig. 3-b vows in the stable state fault diagnosis that the spectral method pair is shaken to vow the curve map that changes with octave;

Full Fig. 3-c vows the curve map that the spectral method phasing degree changes with octave in the stable state fault diagnosis;

Fig. 4-a is the curve map that vector area method vector area changes with octave in the stable state fault diagnosis;

Fig. 4-b is the curve map that vector area method vibration sagittal ratio changes with octave in the stable state fault diagnosis;

Fig. 5-a be in the transient fault diagnosis X axle with the Bode diagram of rotation speed change;

Fig. 5-b be in the transient fault diagnosis Y axle with the Bode diagram of rotation speed change;

Fig. 5-c is the full Bode diagram of vowing in the transient fault diagnosis;

Fig. 5-d be in the transient fault diagnosis vector area with the Bode diagram of rotation speed change.

Embodiment

Rotating machinery is along with the response of the change procedure of some technological parameter and operational factor is one group of complete process signal, and it carries out fault diagnosis and parameter recognition etc. and have important value for the stability of analytical equipment.Through the analysis of one group of process signal, can analyze the vibration characteristics of rotor, the reason of inquiry amplitude and phase change; Obtain the key parameters such as critical rotary speed of unit actual motion; Confirm the unbalance response of rotor, the resonance of research structure and element etc. are one of important evidence of fault diagnosis.

Be among the present invention on basis to existing holographic spectrum, full arrow spectrum, full spectral analysis technology; Systematically analyze the relation of each parameter and rotor-support-foundation system parameter, exciting force parameter; And absorb the advantage that has the rotary machinery fault diagnosis analytical approach now, and proposed to be used for a kind of new method---the vector area method of rotary machinery fault diagnosis, promptly under each frequency multiplication, represent vibrational state with the oval area of the rotor axis movement locus that contains the precession direction; Successively combine to be applied in the actual diagnosis with vibration sagittal ratio; The result shows that it has unique diagnosis effect, is a kind of effective Analysis on Fault Diagnosis new method, is to the innovation of full arrow spectral analysis method and replenishes.

Theoretical based on rotor dynamics, under each response frequency, the axes movement locus of rotor is an ellipse.The vector vibration signal is one group of Dynamic Signal describing the rotor space vibration, is called for short vector signal; Vow that ellipse is to contain the orbit of shaft center ellipse that the vector signal of precession direction is described; Vow that oval area is referred to as vector area to the orbit of shaft center that contains the precession direction, algebraic expression itself contains the vector meaning, the positive and negative precession of positive and negative representative, and numerical value is oval area value.

When using the vector area method to carry out fault diagnosis, at first will arrange the sensor acquisition signal, concrete operations are following: arrange two mutually perpendicular displacement transducers in the rotor cross section, gather the rotor oscillation signal.In vertical plane, the X transducer arrangements in the horizontal direction, Y transducer arrangements in the vertical direction, consistent with the rotor speed direction to the direction of Y by X, employing waits the tach signal collection also to carry out integer-period sampled synchronously with key signal.

According to full arrow spectral technology, the signal that collects is carried out anti-aliasing filtering, LPF etc., remove unnecessary interfering noise signal after, adopt multiple FFT conversion, leading shakes vows that a, pair are shaken and vows the calculating of b:

（1）

On the resultant pair of shaking according to the full master who vows that spectral technology is obtained is shaken the basis of vowing, with vowing ellipse area statement vibrational state characteristic:

Promptly the size of

is represented the oscillation intensity state under this frequency.When

; Rotor is positive precession; When

, rotor is anti-precession.

Vibration sagittal ratio ; Can combine formula (1) to calculate, obtain following result:

size is represented the size and the oval flat degree of the oval excentricity of track, eccentricity; is big more; Eccentricity bigger (ellipse is flat more); The positive and negative precession of positive and negative representative of

:

for just representing the positive precession of rotor,

is the anti-precession of negative indication rotor.

Can be used for understanding XThe shaft vibration absolute value with YMagnitude relationship before the shaft vibration absolute value merges, the relatively suffered exciting force size of rotor both direction.Can prove, if XThe axle with YThe shaft vibration absolute value is equal, then vibration sagittal ratio

Equal 1; If XThe axle with YThe shaft vibration absolute value does not wait, then vibration sagittal ratio

Greater than 1; If XThe shaft vibration absolute value is far longer than YThe shaft vibration absolute value (or XThe shaft vibration absolute value is far smaller than YThe shaft vibration absolute value), vibration sagittal ratio then

Be tending towards infinitely great.

Vibration sagittal ratio can remedy the defective that new method produces erroneous judgement.As when minor axis is far smaller than major axis; Null value appears in the vector area value that new method is drawn in collection of illustrative plates; Can produce the erroneous judgement phenomenon, but combine vibration sagittal ratio, then can successfully differentiate: because this moment, the vibration sagittal ratio absolute value occurred infinitely great in collection of illustrative plates; This frequency lower rotor part axle center vibration shape approximation is a straight line; Be that phase differential is integral multiple, corresponding in such cases a kind of specific fault mode misaligns like shaft coupling.

As Fig. 2 (a～c) is depicted as the curve map that the vector area of new method of the present invention is drawn with different parameters, comparison diagram 1, it is complete that we can clearly relatively draw vector area method and holography spectrum, vow spectrum and full spectrometry to compare the advantage that is had following:

(1) used for reference the advantage of holographic spectrum, be integrated into the oval advantage that quantizes with the oval vibrational state of describing;

(2) use for reference in the full arrow spectrum major semi-axis and represented the advantage that oscillation intensity quantizes, be integrated into the vibration performance of different eccentricities;

(3) use for reference full spectrum and quantized and describe the advantage that two positive radius of circles are judged the precession directions, be integrated into the characteristic that to distinguish vibrational state;

(4) this method is compared with diagnostic method in the past, have aspect rotary machinery fault diagnosis and the control highly sensitive, and stable outstanding feature.

New method of the present invention both can be applied in the stable state fault diagnosis of rotating machinery; Simultaneously when handling the transient process information of rotating machinery; Equally also show outstanding characteristic, the implementation procedure that is applied as routine process in detail during the imbalance fault in stable state fault diagnosis diagnosis is diagnosed with transient fault respectively with regard to this method below.

Certain company double-suction centrifugal pump formula induced draft fan, since 1993 put into operation, the fan platform vibration was strong, had a strong impact on the ordinary production of system.Though, produce little effect through repeatedly testing and keeping in repair.Vow the spectral technology analysis with complete, (shown in a～c), find that 1 frequency multiplication place oscillation intensity is big like Fig. 3.Big according to oscillation intensity under fault characteristic frequency 1 frequency multiplication, judge that this fault possibly be due to basis resonance or the imbalance, which kind of fault can't specifically differentiate is.With this paper method field data is analyzed, shown in Fig. 4 (a), found that area value is big under 1 frequency multiplication, the vertical radial vibration of Y is greater than the vibration on X transverse axis and the Z axle both direction, and these characteristics are all similar with basis resonance or the uneven phenomenon of the failure that causes.

Suppose the vibration that basis resonance causes, the natural frequency on basis is very approaching a little less than the frequency of operation of blower fan or the two so, will produce the excessive vibration of some directions.But learn under 1 frequency multiplication through this paper method diagnostic analysis

Be approximately 1, shown in Fig. 4 (b), can know by analysis before,

=1 expression XThe axle with YThe shaft vibration absolute value equates, does not have excessive vibration in a certain direction in this explanation physical fault, is caused by basis resonance so fix a breakdown.

Suppose the vibration that imbalance causes; Though there is phase differential in the vibration of each point; But vertical diameter is to vibrating all bigger (promptly

is less) with horizontal radial; Be approximately 1 with

under 1 frequency multiplication with this paper methods analyst and be consistent, for this reason the fault occurrence cause.Carry out balance test discovery fault just by due to the rotor unbalance through removing.

Vector area method collection of illustrative plates and additive method single channel analytic approach, dual-channel analysis method (like holography spectrum, full spectrum, the full spectrum etc. of vowing) are compared, and the vector area value under more obvious, the single or fault characteristic frequency of fault characteristic frequency is bigger and single.Through the further investigation failure mechanism, and, further sum up vibration sagittal ratio characteristics different under the power frequency fault signature with new method of the present invention through lot of test.Under identical fault characteristic frequency, can distinguish different faults effectively in conjunction with vibration sagittal ratio, may be used in the actual diagnosis, improve the accuracy of diagnosis.

The power frequency failure symptom that table 1 is summed up through the vector area method

?	Characteristic frequency	| vibration sagittal ratio |	Axial vibration	Orbit of shaft center	Amplitude is with rotation speed change
						Uneven	1X	Near 1	Less	Near circle	Change little
Base flexible	1X	Bigger	?	Ellipse is more flat	Possibly reduce
						Rotor bow	1X	Near 1	Bigger	Near circle	Amplitude can drop to minimum value in the raising speed
The sound friction	1X, companion's higher hamonic wave	Bigger	?	" wedge angle " arranged	Change little

In last table, axial vibration be dewater in the three dimensions square to and vertical direction (this both direction information fusion) outside, another channel axis is taken out the characteristic quantity that carries out aid analysis to value separately.Orbit of shaft center is the trace graphics after binary channels merges, i.e. the calculating figure of vector area, and the size of vector area value is the size of axle center trace graphics area value under each frequency just; And amplitude refers to the size of vector area here with " amplitude " in the rotation speed change, refers to here under the natural frequency that the vector area value is with change in rotational speed.

In the start-stop process, rotor has experienced various rotating speeds, and its vibration signal is the response of rotor-support-foundation system to rotation speed change; It is the external reflection of rotor dynamics and failure symptom; Comprised and be difficult to the abundant information that obtains at ordinary times, therefore, the start-stop process analysis procedure analysis is an important process of rotor monitoring.The same with full arrow spectral technology; The vector area method is when handling rotating machinery transient process information; Equally also show outstanding characteristic---can accurately find the resonant frequency and the critical rotary speed value of rotor-support-foundation system, it is the method for expressing by Bode diagram, thereby accurately judges the critical rotary speed of rotor-support-foundation system; Guidance is provided with the working speed of machine and avoids critical rotary speed, in order to avoid machine resonates.

(be followed successively by Bode diagram that the X axle draws, Bode diagram that the Y axle is drawn shown in a～d), vow the Bode diagram that Bode diagram and vector area method are drawn entirely, the Bode diagram that the vector area method is drawn is that the rotor axis movement locus area value under each rotating speed is plotted in the curve map that rectangular coordinate is fastened like Fig. 5.

Shown in Fig. 5-a; Vibration under the 3150r/s rotating speed be to the maximum 110

; And in Fig. 5-c, can obtain, the vibration under the 3250r/s rotating speed be to the maximum 148

.This shows that this traditional single channel analytic approach changes with the selection of X, Y passage, can't specifically confirm the critical rotary speed value size of this equipment.Vibration by full arrow Bode diagram 5-c can analyze under the 3200r/s is maximum, and the Bode diagram 5-d that draws with the vector area method equally accurately intuitive analysis go out the vibration maximum under the 3200r/s, and vow that more full Bode diagram is more clear and intuitive.This figure ordinate is represented is not rotor value of shaking of a certain passage under the different rotating speeds in rising the car process; But the area value of rotor axis movement locus; Thereby make the transient signal characteristic performance that rises the car process obvious especially, and this remarkable performance can not change with the passage variation as traditional analysis.

Claims (2)

1. the stable state method for diagnosing faults of a rotating machinery, it is characterized in that: the step of this method is following:

(1) arranges two mutually perpendicular displacement transducers in the rotor cross section; Gather the rotor oscillation signal: in vertical plane; The X transducer arrangements in the horizontal direction; Y transducer arrangements in the vertical direction, consistent with the rotor speed direction to the direction of Y by X, employing waits the tach signal collection and carries out integer-period sampled synchronously with key signal;

(2) signal of gathering is carried out anti-aliasing filtering, LPF, remove unnecessary interfering noise signal;

(3) adopt multiple FFT conversion, leading shakes vows that a, pair are shaken and vows that b calculates;

(4) calculate vector area S (k) and the vibration sagittal ratio ε that vows ellipse: vector area is that the orbit of shaft center that contains the precession direction is vowed oval area; It is big or small to express single-frequency measuring point oscillation intensity down with the size of vector area value, the positive and negative precession of the positive and negative expression rotor of vector area value: promptly | S (k) | size represent the oscillation intensity state under this frequency; S (k)＞0 o'clock, rotor was positive precession, and S (k)＜0 o'clock, rotor was anti-precession; ε is used to explain the X axis vibration absolute value and the Y axis vibration absolute value merges preceding magnitude relationship; Compare the suffered exciting force size of rotor both direction: | ε |=1 expression X axle and Y axis vibration absolute value are equal, | ε |=∝ representes that X axis vibration absolute value and Y axis vibration absolute value differ infinitely great;

(5) vector area and vibration sagittal ratio the graph of a relation that draws with respect to frequency multiplication or other variable;

(6) in the stable state fault diagnosis; Vector area S (k), vibration sagittal ratio ε and graph of a relation are analyzed: the oscillation intensity under the first read fortune fault characteristic frequency together; It is the vector area value; Analyze possible fault type, differentiate the common particular type that combines to confirm fault again according to size and orbit of shaft center, axial vibration and the amplitude change rate of vibration sagittal ratio under the corresponding fault characteristic frequency; When handling transient process information, in conjunction with the method for expressing of Bode diagram, the instantaneous graph of a relation of the vector area of drawing, pairing frequency of vector area value maximum and tachometer value are the resonant frequency and the critical rotary speed value of rotor-support-foundation system in the analysis collection of illustrative plates.

2. the method for diagnosing faults of rotating machinery according to claim 1 is characterized in that: the shake computing method of arrow, vibration sagittal ratio and vector area of the main arrow that shakes, pair are following:

$\left\{\begin{array}{c}a=\frac{1}{2}\left[\right|Z\left(k\right)|+|Z(N-k)\left|\right]\\ b=\frac{1}{2}\left[\right|Z\left(k\right)|-|Z(N-k)\left|\right]\end{array}\right.---\left(1\right)$

$\left\{\begin{array}{c}\mathrm{\ϵ}=\frac{a}{b}=\frac{\left|Z\left(k\right)\right|+\left|Z(N-k)\right|}{\left|Z\left(k\right)\right|-\left|Z(N-k)\right|}\\ S\left(k\right)=\mathrm{\πab}=\mathrm{\π}\·\frac{1}{2}\left[\right|Z\left(k\right)|+|Z(N-k)\left|\right]\·\frac{1}{2}\left[\right|Z\left(k\right)|-|Z(N-k)\left|\right]=\frac{1}{4}\\ (k=\mathrm{0,1,2},...,N/2-1)\end{array},\mathrm{\π}[{\left|Z\left(k\right)\right|}^2-{\left|Z(N-k)\right|}^2]\right.---\left(2\right)$

In the formula, a, b represent the main arrow that shakes, the pair arrow that shakes respectively, and ε representes vibration sagittal ratio, and S (k) representes vector area.

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