CN104344951A - Leaf apex vibration amplitude measuring method - Google Patents

Abstract

The invention relates to a leaf apex vibration amplitude measuring method. The leaf apex vibration amplitude measuring method comprises the following steps that under a small leaf apex amplitude, a reading microscope is used for reading the leaf apex vibration amplitude, fitting calculation is conducted on the leaf apex vibration amplitude and a leaf vibration small range testing value measured by a non-contact type sensor, and a linear relation equation of the leaf apex vibration amplitude and the non-contact type sensor measuring vibration value is obtained; under a large leaf apex, a leaf apex vibration value measured by the non-contact type sensor is obtained, the leaf apex vibration amplitude is converted from the vibration value measured by the non-contact type sensor by the linear relation equation, and the measuring of the leaf apex vibration amplitude is realized. The leaf apex vibration amplitude measuring method is applied in a real large-scale leaf fatigue test, the effect is obvious, the test requirement is completely satisfied, the quality and the reliability of the large amplitude leaf vibration fatigue test are guaranteed, and the problem that the vibration amplitude measuring is difficult caused by the over-large size of the leaf structure is solved.

Description

A kind of blade tip vibration amplitude measuring method

Technical field

The present invention relates to the measuring technique of a kind of aeromotor field Leaf, specifically a kind of blade tip vibration amplitude measuring method.

Background technology

In blade of aviation engine vibration fatigue test, strainometer is usually adopted to measure blade vibration stress value, limited owing to becoming meter testing range on the one hand, the vibration stress of below 8000 microstrains can only be tested; On the other hand under repeatedly large stress vibration cycles, strainometer often damages, and cannot complete blade and vibrate certification test for a long time.Therefore, in the large stress situation of pilot blade, general employing is measured blade tip vibration amplitude and is monitored blade vibration fatigue examination stress value, is read under normal circumstances by reading microscope to blade tip vibration amplitude.But when blade vibration amplitude reaches 15mm ~ 20mm, blade tip vibration luminous point will be smudgy, and reading microscope is just difficult to measure.In aeromotor and gas turbine production run, all spinner blades, after completing production and processing, before assembling engine, must carry out blade fatigue intensity certification test, only have and just allow installation to use by qualified batch of blade of certification test.

Along with development and the widespread use of aeromotor and gas turbine, particularly the development of ground combustion machine and high thrust fanjet generates, fan and low-pressure rotor blade physical dimension increasing, during vibrating fatigue certification test, blade tip vibration amplitude can reach more than 50mm, reads blade tip amplitude like this carry out blade vibration stress value monitoring just very difficult realization by reading microscope.Therefore a kind of blade tip vibration amplitude measuring method of wide range must be developed.

At present, there is not been reported can to monitor the blade tip vibration amplitude measuring method of more than 50mm.

Summary of the invention

Cannot measure the deficiencies such as the large vibration amplitude of blade of aviation engine for reading microscope in prior art, the technical problem to be solved in the present invention is to provide a kind of blade tip vibration amplitude measuring method meeting large amplitude blade vibration test.

For solving the problems of the technologies described above, the technical solution used in the present invention is:

A kind of blade tip vibration amplitude of the present invention measuring method comprises the following steps:

Under the little amplitude of blade tip, reading microscope is adopted to read blade vibration amplitude,

Carry out the Fitting Calculation by the blade vibration small-range test value measured blade tip vibration amplitude and non-contacting sensor, obtain the linear relationship equation of blade tip vibration amplitude and non-contact sensor measuring vibrations value;

Under blade tip large amplitude, the blade tip vibration values recorded by non-contact sensor;

The vibration values recorded by non-contact sensor converses blade tip vibration amplitude by above-mentioned linear relationship equation, realizes the measurement of blade tip vibration amplitude.

The linear relationship equation of described blade tip vibration amplitude and non-contact sensor measuring vibrations value is as follows:

$S=\frac{k}{f_0}\·u$

$k=\frac{{\left({\mathrm{\Σ}}_{i=1}^n{s}_i{f}_0\right)}^2-n\left[{\mathrm{\Σ}}_{i=1}^n{\left(s_i{f}_0\right)}^2\right]}{\left({\mathrm{\Σ}}_{i=1}^n{v}_i\right)\left({\mathrm{\Σ}}_{i=1}^n{s}_i{f}_0\right)-n\left({\mathrm{\Σ}}_{i=1}^n{v}_i{s}_i{f}_0\right)}$

Wherein, S is blade tip vibration amplitude, and k is equation intermediate variable, f ₀for Natural Frequency of Blade value, u is non-contact electric eddy Sensor Vibration value, v _ifor i-th group of vibration values reading of non-contact electric eddy sensor test, s _ifor i-th group of blade tip vibration amplitude of reading microscope test, i is blade tip amplitude group number sequence number, and n is blade tip group number maximal value.

In measurement blade small-range vibration amplitude, blade tip vibration amplitude and non-contact electric eddy Sensor Vibration value fitting calibrating process and pilot blade blade tip wide range vibration amplitude process, keep non-contact electric eddy sensing station to immobilize, the change of horizontal or vertical direction must not be had.

Blade tip vibration amplitude under adopting reading microscope to read ascending 5 ~ 7 groups of ladder level of vibrations, employing non-contact sensor measured value is and blade vibration amplitude (unit mm) the corresponding vibration values (unit mv) under above-mentioned 5 ~ 7 groups of ladder level of vibrations.

The maximum vibration amplitude measured must not exceed 30% of blade tip examination stress.

The little amplitude of described blade tip is the amplitude of vibration amplitude lower than 20mm; Blade tip large amplitude is the amplitude that vibration amplitude is more than or equal to 20mm.

The present invention has following beneficial effect and advantage:

1. the present invention is applied in actual large-scale blade fatigue test, and successful, meets testing requirements completely, ensure that large amplitude vibration fatigue test of blade quality and reliability, solves the problem that the vibration amplitude caused because blade construction is oversize measures difficulty.

2. the inventive method can be widely used in aeromotor or the large-scale fan of gas turbine, compressor blade vibration test, for vibration fatigue test Leaf blade tip amplitude monitoring technology provides a kind of brand-new means of testing, expand blade fatigue test measuring technology.

Accompanying drawing explanation

Fig. 1 is the inventive method Leaf blade tip vibration amplitude and non-contact electric eddy Sensor Vibration value curve fitting process schematic diagram;

Fig. 2 is the inventive method Leaf blade tip vibration amplitude instrumentation plan.

Wherein, 1 is non-contact electric eddy sensor, and 2 is blade, and 3 is fixture, and 4 is vibroscope, and 5 is milivoltmeter, and 6 is reading display device.

Embodiment

Below in conjunction with Figure of description, the present invention is further elaborated.

A kind of blade tip vibration amplitude of the present invention measuring method is under the little amplitude of blade tip, reading microscope 6 is adopted to read blade vibration amplitude, carry out the Fitting Calculation by the blade vibration test value (voltage signal values) measured blade tip vibration amplitude and non-contacting sensor, obtain the linear relationship equation of blade tip vibration amplitude and non-contact sensor measuring vibrations value (milivoltmeter 5 displayed value).After obtaining linear equation, in blade vibration process of the test, the vibration values recorded by non-contact sensor, converses blade tip vibration amplitude, realizes the measurement of blade tip vibration amplitude.

The inventive method comprises the following steps:

Under the little amplitude of blade tip (namely amplitude is lower than 20mm), reading microscope 6 is adopted to read blade vibration amplitude; As shown in Figure 1;

Carry out the Fitting Calculation by the blade vibration small-range test value measured blade tip vibration amplitude and non-contacting sensor (the present embodiment adopts current vortex sensor 1), obtain the linear relationship equation of blade tip vibration amplitude and non-contact sensor measuring vibrations value;

Under blade tip large amplitude (namely amplitude is more than or equal to 20mm), the blade tip vibration amplitude recorded by non-contact sensor, as shown in Figure 2;

The vibration amplitude recorded by non-contact sensor converses blade tip vibration amplitude by above-mentioned linear relationship equation, realizes the measurement of blade tip vibration amplitude.

The blade vibration amplitude adopting reading microscope to read is the blade vibration amplitude under ascending 5 ~ 7 groups of ladder level of vibrations, vibration measurements (the i.e. milivoltmeter displayed value of non-contact sensor, unit mv) be the vibration values corresponding with the blade tip vibration amplitude (i.e. reading microscope test value, unit mm) under above-mentioned 5 ~ 7 groups of ladder level of vibrations.

As shown in Figure 1, blade tip vibration-testing value (voltage signal values mv) when blade tip one bending vibration is moved is monitored with current vortex sensor 1, blade tip vibration amplitude is measured with reading microscope 6, ascending blade vibration amplitude (the i.e. reading microscope test value measured under 5 ~ 7 groups of ladder level of vibrations, unit mm) and vibration values (the i.e. milivoltmeter displayed value measured of non-contact sensor corresponding to corresponding vibration amplitude, unit mv), maximum vibration amplitude must not exceed 30% of blade examination stress.Note non-contact electric eddy sensor 1 position will being kept to fix in measurement blade vibration amplitude process, the change of horizontal or vertical direction can not be had.Calculated the Fitting curve equation of blade tip vibration amplitude S and non-contact electric eddy sensor 1 vibration-testing value u by test data, equation model computing method are as follows:

$S=\frac{k}{f_0}\·u$

$k=\frac{{\left({\mathrm{\Σ}}_{i=1}^n{s}_i{f}_0\right)}^2-n\left[{\mathrm{\Σ}}_{i=1}^n{\left(s_i{f}_0\right)}^2\right]}{\left({\mathrm{\Σ}}_{i=1}^n{v}_i\right)\left({\mathrm{\Σ}}_{i=1}^n{s}_i{f}_0\right)-n\left({\mathrm{\Σ}}_{i=1}^n{v}_i{s}_i{f}_0\right)}$

Wherein, S is blade tip vibration amplitude, and k is that (intermediate variable is that vibration values (milivoltmeter displayed value) matching of blade tip vibration amplitude and the corresponding sensor measurement tested by reading microscope under above-mentioned 5 ~ 7 groups of ladder level of vibrations obtains to equation intermediate variable.), f ₀for Natural Frequency of Blade value, unit is Hz; U is non-contact electric eddy sensor 1 vibration-testing value, v _ibe i-th group of non-contact electric eddy sense vibration test value reading, unit is mv, s _ibe i-th group of blade tip vibration amplitude, unit is mm, i is blade tip group number sequence number, and n is blade tip group number maximal value.

Complete after above-mentioned blade tip vibration amplitude and non-contact electric eddy sensor 1 vibration-testing value Fitting curve equation calculate, obtain the relation equation S=ku/f of blade tip vibration amplitude S and non-contact electric eddy sensor 1 vibration-testing value u ₀, adjustment shaking table exports energy, when non-contact electric eddy sensor 1 vibration-testing value is u ₀time, can be calculated now blade vibration amplitude S by equation model ₀=ku ₀/ f ₀, so just can measure reading microscope immeasurable blade wide range vibration amplitude.

Note at blade tip vibration amplitude and non-contact electric eddy sensor 1 vibration-testing value fitting calibrating process until non-contact electric eddy sensor 1 position will be kept to immobilize in pilot blade blade tip wide range vibration amplitude process.Test process is as Fig. 2.

Case:

(1) blade tip vibration amplitude and non-contact eddy current sensor vibration-testing value Fitting curve equation calculate

With electromagnetic vibration generator system Turbine Blade 2, blade tip vibration amplitude is read with reading microscope 6, with non-contact eddy current sensor 1 pilot blade vibration values (magnitude of voltage, read by milivoltmeter 5, vibroscope 4 be used for nurse one's health amplification sensor test vibration signal, by conditioning after vibration signal be transferred to milivoltmeter display., test result is as table one:

Table one test figure

(2) blade tip vibration amplitude is measured

Blade frequencies value f ₀=1279Hz, the Fitting curve equation being calculated blade tip vibration amplitude S and non-contact eddy current sensor 1 vibration-testing value u by table one data obtains: S=0.0060003596u, as non-contact eddy current sensor vibration-testing value u=1250mv, calculate S=7.5mm by fit equation.By reading microscope, measurement is carried out to blade tip actual vibration amplitude and verify to obtain S ₀=7.58mm.

By above-mentioned verification experimental verification, can meet linear relationship in blade tip little amplitude range intra vane blade tip vibration amplitude and non-contact sensor measuring vibrations value, above-mentioned linear relationship can directly be extended to large amplitude scope.

Claims (6)

1. a blade tip vibration amplitude measuring method, is characterized in that comprising the following steps:

Under the little amplitude of blade tip, reading microscope is adopted to read blade vibration amplitude,

Carry out the Fitting Calculation by the blade vibration small-range test value measured blade tip vibration amplitude and non-contacting sensor, obtain the linear relationship equation of blade tip vibration amplitude and non-contact sensor measuring vibrations value;

Under blade tip large amplitude, the blade tip vibration values recorded by non-contact sensor;

The vibration values recorded by non-contact sensor converses blade tip vibration amplitude by above-mentioned linear relationship equation, realizes the measurement of blade tip vibration amplitude.

2., by blade tip vibration amplitude measuring method according to claim 1, it is characterized in that: the linear relationship equation of described blade tip vibration amplitude and non-contact sensor measuring vibrations value is as follows:

$s=\frac{k}{f_0}\·u$

$k=\frac{{\left({\mathrm{\Σ}}_{i=1}^n{s}_i{f}_0\right)}^2-n\left[{\mathrm{\Σ}}_{i=1}^n{\left(s_i{f}_0\right)}^2\right]}{\left({\mathrm{\Σ}}_{i=1}^n{v}_i\right)\left({\mathrm{\Σ}}_{i=1}^n{s}_i{f}_0\right)-n\left({\mathrm{\Σ}}_{i=1}^n{v}_i{s}_i{f}_0\right)}$

Wherein, S is blade tip vibration amplitude, and k is equation intermediate variable, f ₀for Natural Frequency of Blade value, u is non-contact electric eddy Sensor Vibration value, v _ifor i-th group of vibration values reading of non-contact electric eddy sensor test, s _ifor i-th group of blade tip vibration amplitude of reading microscope test, i is blade tip amplitude group number sequence number, and n is blade tip group number maximal value.

3. by blade tip vibration amplitude measuring method according to claim 1, it is characterized in that: in measurement blade small-range vibration amplitude, blade tip vibration amplitude and non-contact electric eddy Sensor Vibration value fitting calibrating process and pilot blade blade tip wide range vibration amplitude process, keep non-contact electric eddy sensing station to immobilize, the change of horizontal or vertical direction must not be had.

4. by blade tip vibration amplitude measuring method according to claim 1, it is characterized in that: the blade tip vibration amplitude under adopting reading microscope to read ascending 5 ~ 7 groups of ladder level of vibrations, employing non-contact sensor measured value is and blade vibration amplitude (unit mm) the corresponding vibration values (unit mv) under above-mentioned 5 ~ 7 groups of ladder level of vibrations.

5. by the blade tip vibration amplitude measuring method described in claim 1 or 4, it is characterized in that: the maximum vibration amplitude of measurement must not exceed 30% of blade tip examination stress.

6., by blade tip vibration amplitude measuring method according to claim 1, it is characterized in that: the little amplitude of described blade tip is the amplitude of vibration amplitude lower than 20mm; Blade tip large amplitude is the amplitude that vibration amplitude is more than or equal to 20mm.