CN102505970B - Device and method for monitoring crack propagation life of turbine rotor - Google Patents

Abstract

The invention provides a device and a method for monitoring internal crack propagation life of a turbine rotor. The method includes the specific steps of: flaw detection and determination of crack size of the turbine rotor; computation of maximum main stress of parts where the crack is; computation of a critical crack size of the turbine rotor; computation of crack propagation life of the turbine rotor; computation of accumulation loss of the crack propagation life of the rotor in an overspeed test process device; computation of the accumulation loss of the internal crack propagation life of the turbine rotor; computation of the internal crack propagation residue life of the turbine rotor; controlling the crack propagation residue life of the turbine rotor; and printing an output result. The device and the method have the advantages that: the residual crack propagation life of the turbine rotor can be calculated on line and monitored regularly; if the residual crack propagation life of the turbine rotor is relatively short, the residual crack propagation life of the turbine rotor is rationally used by immediately overhauling (A-level overhaul); therefore, a technical scheme that the residual crack propagation life of the turbine rotor is monitored regularly is achieved.

Description

The supervising device in turbine rotor propagation of internal cracks life-span and method

Technical field

The supervising device and the method that the present invention relates to the turbine rotor propagation of internal cracks life-span, belong to steam turbine technology field.

Background technology

The feature of turbine rotor is that size is large, High Rotation Speed, and turbine rotor produces large principle stress in startup, shutdown and overspeed test process.The defect detecting test that turbine rotor produces in forging and process can not be found crackle, and in steam turbine operation process, turbine rotor, under the effect of large principle stress, will likely expand to defect detecting test visible crack.In steam turbine operation process, turbine rotor is under the effect of large principle stress, and rotor defect detecting test visible crack is constantly expanded.When the Crack Extension of turbine rotor is during to the critical crack size at rotor crack position, just likely there is brittle fracture in turbine rotor, causes steam turbine damage accident.Existing turbine rotor service life supervision technology, provided the method for supervising of the crack initiation life of turbine rotor, and the monitoring of the crack propagation life of in-service turbine rotor does not also have suitable apparatus and method available.

Summary of the invention

The supervising device and the method that the object of this invention is to provide a kind of turbine rotor propagation of internal cracks life-span, realize the regular monitoring of crack propagation life of turbine rotor.

For realizing above object, technical scheme of the present invention is to provide the supervising device in a kind of turbine rotor propagation of internal cracks life-span, it is characterized in that, by ultra-sonic defect detector, calculation server, database server, web page server and user side browser, formed, ultra-sonic defect detector is connected with database server, calculation server is connected with database server and web page server, and web page server is connected with database server, calculation server and user side browser respectively.

The present invention also provides the method for supervising in the turbine rotor propagation of internal cracks life-span that said apparatus adopts, it is characterized in that, adopt the computer software of the crack propagation life of turbine rotor of C language compilation, operate on calculation server, be applied to the monitoring of crack propagation life of turbine rotor, concrete steps are:

The first step: the crack size of turbine rotor is determined in flaw detection:

At steam turbine, open between the turn(a)round of cylinder, adopt ultra-sonic defect detector to determine position, place and the crack size of crackle, position, crackle place refers to three coordinate values of rotor Ellipse crack center, and crack size refers to minor axis radius a and the major axis radius c of the Ellipse crack of rotor;

Second step: the major principal stress of calculating position, crackle place:

For internal rotor crackle, calculate cold start, warm starting, hot starting, hot start, very hot startup and the 110% nominal operation over speed of rotation test major principal stress of totally five kinds of transient processes, use respectively symbol σ _1c, σ _1w, σ _1h, σ _1rand σ _10srepresent;

The 3rd step: the critical crack size of calculating turbine rotor:

The critical crack size a of turbine rotor i kind transient condition _cicomputing formula be:

$a_{\mathrm{ci}}={\mathrm{\σ}}_{1i}\sqrt{\mathrm{Ma}}$

In formula:

σ _1i---the major principal stress of i kind transient condition

A---Ellipse crack minor axis radius

M---the constant relevant with crack shape parameter Q,

For underbead crack,

For surface crack,

$Q={\&Integral;}_0^{\frac{\mathrm{\&pi;}}{2}}(1-\frac{c^2-a^2}{{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="111213105950.png"\; state="\{\{state\}\}">c</figure-callout>}}^2}{\sin }^2\mathrm{\&theta;})\mathrm{d\&theta;}$

C---Ellipse crack major axis radius

θ---cross the radial line of any point and the angle of transverse on crackle contour

The 4th step: calculate crack propagation life of turbine rotor

The crack propagation life of turbine rotor N of i kind transient condition _ficomputing formula be:

$N_{\mathrm{fi}}=\frac{2}{(m_0-2)C_0{\mathrm{\&sigma;}}_{1i}^{m_0}{M}^{\frac{m_0}{2}}}[\frac{1}{a^{\frac{(m_0-2)}{2}}}-\frac{1}{{a_{\mathrm{ci}}}^{\frac{(m_0-2)}{2}}}]$

In formula:

C ₀, m ₀---rotor material crack expansion test constant;

The 5th step: calculate overspeed test process rotor crack expansion life-span integration loss:

In the overspeed test process of turbine rotor, all larger at the surperficial principle stress of internal rotor and rotor, the crack propagation life integration loss E that turbine rotor causes due to overspeed test _f0computing formula be:

$E_{f0}=\frac{n_{\mathrm{os}}}{N_{\mathrm{fos}}}$

In formula:

N _os---overspeed test of steam turbine number of times

N _fos---the crack propagation life in overspeed test process;

The 6th step: calculate turbine rotor propagation of internal cracks life-span integration loss:

In the start-up course of steam turbine, major principal stress appears at internal rotor, turbine rotor propagation of internal cracks life-span integration loss E _f1computing formula be:

$E_{f1}=\frac{n_c}{N_{\mathrm{fc}}}+\frac{n_w}{N_{\mathrm{fw}}}+\frac{n_h}{N_{\mathrm{fh}}}+\frac{n_r}{N_{\mathrm{fr}}}$

In formula:

N _c---the cold start number of times of actual motion

N _w---the warm starting number of times of actual motion

N _h---the hot starting, hot start number of times of actual motion

N _r---the very hot startup number of times of actual motion

N _fc---crack propagation life in cold start process

N _fw---crack propagation life in warm starting process

N _fh---crack propagation life in hot starting, hot start process

N _fr---crack propagation life in very hot startup process

The 7th step: calculate turbine rotor propagation of internal cracks residual life:

Turbine rotor propagation of internal cracks residual life R _l1computing formula be:

$R_{L1}=\frac{1-E_{f0}-E_{f1}}{e_{y1}}$

In formula:

E _y1---the average annual crack propagation life loss of internal rotor,

M---find crackle calendar year number so far;

The 8th step: control Cracks in Turbine Rotors expansion residual life

If the propagation of internal cracks residue calendar life-span R of turbine rotor _l1(or external crack expansion residue calendar life-span R _l2) <4, scheme of arrangement overhaul within the year (maintenance of A level), is overhauled or is changed according to result of detection; If 4 years≤R _l1(or R _l2) <8, scheme of arrangement overhaul after 1 year but in 4 years (maintenance of A level), is overhauled or is changed according to result of detection; If 8 years≤R _l1(or R _l2) <16, in upper once scheduled major overhaul (maintenance of A level), give detailed defect detecting test; If R _l1(or R _l2)>=16 year, according to scheduled major overhaul (maintenance of A level) cycle and the scheduled major overhaul project of the overhaul of the equipments guide rule > > of < < electricity power enterprise (DL/T838) arrangement steam turbine;

The 9th step: printout result

Output Cracks in Turbine Rotors is expanded result of calculation and the control measure of residual life, is applied to the Optimal Maintenance of steam turbine.

Preferably, the concrete steps of described second step are: the mechanical model of setting up the rotational symmetry FEM (finite element) calculation of turbine rotor; Adopt existing finite element analysis technology, for underbead crack, calculate cold start, warm starting, hot starting, hot start, very hot startup and the 110% nominal operation over speed of rotation test major principal stress of totally five kinds of transient processes.

The present invention has following characteristics: at steam turbine during one's term of military service; during turbine rotor scheduled major overhaul; adopt ultra-sonic defect detector; flaw detection draws the surface crack of turbine rotor and position, place and the crack size of underbead crack; be kept at database server; use the method for supervising of crack propagation life of turbine rotor provided by the invention; according to monthly different startups and shutdown number of times; the Crack Extension residual life of quantitative assessment turbine rotor, for safe operation and the Optimal Maintenance of turbine rotor provide foundation.

Advantage of the present invention be realized Cracks in Turbine Rotors expansion residual life in line computation and regular monitoring; If the Crack Extension residual life of turbine rotor partially in short-term, by timely scheme of arrangement overhaul (maintenance of A level), rationally use the Crack Extension residual life of turbine rotor, reached the technique effect of regular monitoring Cracks in Turbine Rotors expansion residual life.

Accompanying drawing explanation

Fig. 1 is the block scheme of crack propagation life of turbine rotor supervising device of the present invention;

Fig. 2 is the process flow diagram of crack propagation life of turbine rotor method for supervising of the present invention;

Fig. 3 is the computer software block diagram that calculation server of the present invention adopts;

Fig. 4 is the schematic diagram of certain model 300MW Low Pressure Steam Turbine structure.

Embodiment

Below in conjunction with embodiment, illustrate the present invention.

Embodiment

As shown in Figure 1, the block scheme of crack propagation life of turbine rotor supervising device of the present invention, crack propagation life of turbine rotor device of the present invention is comprised of ultra-sonic defect detector 1, calculation server 2, database server 3, web page server 4 and user side browser 5, ultra-sonic defect detector 1 is connected with database server 3, calculation server 2 is connected with database server 3 and web page server 4, and web page server 4 is connected with database server 3, calculation server 2 and user side browser 5 respectively.

As shown in Figure 2, the process flow diagram of crack propagation life of turbine rotor method for supervising of the present invention, as shown in Figure 3, the computer software block diagram that calculation server of the present invention adopts, this software is arranged on the calculation server of crack propagation life of turbine rotor, is applied to the calculation and control of crack propagation life of turbine rotor.

For certain model 300MW steam turbine, the structure of low pressure rotor employing welded disc turbine rotor as shown in Figure 4, at this 300MW steam turbine during one's term of military service, adopt the computer software shown in device, the process flow diagram shown in Fig. 2 and the Fig. 3 shown in Fig. 1, calculate the result of calculation of low pressure rotor crack propagation life.

The first step: open at steam turbine between the turn(a)round of cylinder, adopt ultra-sonic defect detector to determine position, place and the crack size of crackle, adopt ultra-sonic defect detector to record rotor mother metal position A corresponding to the middle weld seam of this 300MW Low Pressure Steam Turbine and have an Ellipse crack, its minor axis radius is a=2mm, c=10mm;

Second step: the mechanical model of setting up the rotational symmetry FEM (finite element) calculation of turbine rotor, adopt existing finite element analysis technology, calculate cold start, warm starting, hot starting, hot start, very hot startup and the 110% nominal operation over speed of rotation test major principal stress of totally five kinds of transient processes, use respectively symbol σ _1c, σ _1w, σ _1h, σ _1rand σ _10srepresent;

The 3rd step: the critical crack size of calculating turbine rotor:

The critical crack size a of turbine rotor i kind transient condition _cicomputing formula be:

$a_{\mathrm{ci}}={\mathrm{\&sigma;}}_{1i}\sqrt{\mathrm{Ma}}$

In formula:

σ _1i---the major principal stress of i kind transient condition

A---Ellipse crack minor axis radius

M---the constant relevant with crack shape parameter Q,

For underbead crack,

For surface crack,

$Q={\&Integral;}_0^{\frac{\mathrm{\&pi;}}{2}}(1-\frac{c^2-a^2}{{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="111213105950.png"\; state="\{\{state\}\}">c</figure-callout>}}^2}{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="111213105950.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&theta;})\mathrm{d\&theta;}$

C---Ellipse crack major axis radius

θ---cross the radial line of any point and the angle of transverse on crackle contour

The 4th step: calculate crack propagation life of turbine rotor

The crack propagation life of turbine rotor N of i kind transient condition _ficomputing formula be:

$N_{\mathrm{fi}}=\frac{2}{(m_0-2)C_0{\mathrm{\&sigma;}}_{1i}^{m_0}{M}^{\frac{m_0}{2}}}[\frac{1}{a^{\frac{(m_0-2)}{2}}}-\frac{1}{{a_{\mathrm{ci}}}^{\frac{(m_0-2)}{2}}}]$

In formula:

C ₀, m ₀---rotor material crack expansion test constant, C ₀=9.2 × 10 ^-12, m ₀=2.54;

The start operating performance that this 300MW Low Pressure Steam Turbine position A is corresponding different and the major principal stress σ of overspeed test operating mode _1i, critical crack size a _ciwith crack propagation life N _firesult of calculation is listed in table 1;

[table 1]

The 5th step: this 300MW steam turbine put into operation from September, 1989, carries out overspeed test 25 times altogether in September, 2011, the crack propagation life integration loss E that this Low Pressure Steam Turbine causes due to overspeed test _f0result of calculation be:

$E_{f0}=\frac{n_{\mathrm{os}}}{N_{\mathrm{fos}}}=\frac{25}{1608}=0.015547$

The 6th step: this steam turbine put into operation in September, 2011 from September, 1989, the cold start frequency n of actual motion _c=71, the warm starting frequency n of actual motion _w=502, the hot starting, hot start frequency n of actual motion _h=2106 times, the very hot startup frequency n of actual motion _r=108 times, the crack propagation life integration loss E of this 300MW Low Pressure Steam Turbine position A _f1result of calculation be:

$E_{f1}=\frac{n_c}{N_{\mathrm{fc}}}+\frac{n_w}{N_{\mathrm{fw}}}+\frac{n_h}{N_{\mathrm{fh}}}+\frac{n_r}{N_{\mathrm{fr}}}=\frac{71}{2167}+\frac{502}{3292}+\frac{2106}{3865}+\frac{108}{3688}=0.759429$

The 7th step: this Low Pressure Steam Turbine discovery crackle has been on active service 22 years so far, and m=22, has $e_{y1}=\frac{E_{f0}+E_{f1}}{m}=\frac{0.015547+0.759429}{22}=0.035226,$ This 300MW Low Pressure Steam Turbine position A Crack Extension residual life R _l1result of calculation be:

The 8th step and the 9th step: the 4 years≤R of result of calculation of this model 300MW Low Pressure Steam Turbine position A Crack Extension residual life _l1=6.4 years <8, the control measure of recommendation are: scheme of arrangement overhaul after 1 year but in 4 years (maintenance of A level), according to result of detection, overhauled or changed, printout result.

Adopt supervising device and the method for crack propagation life of turbine rotor provided by the invention, quantitatively calculate the Crack Extension residual life of this 300MW Low Pressure Steam Turbine and recommend out control measure, according to the crack propagation life of this low pressure rotor, carry out scheme of arrangement overhaul (maintenance of A level), for safe operation and the Optimal Maintenance of this 300MW Low Pressure Steam Turbine provide foundation.

Claims (2)

1. the method for supervising in a turbine rotor propagation of internal cracks life-span, adopt the supervising device in a kind of turbine rotor propagation of internal cracks life-span, the supervising device in described turbine rotor propagation of internal cracks life-span is by ultra-sonic defect detector, calculation server, database server, web page server and user side browser composition, ultra-sonic defect detector is connected with database server, calculation server is connected with database server and web page server, web page server respectively with database server, calculation server is connected with user side browser, it is characterized in that, adopt the computer software of the crack propagation life of turbine rotor of C language compilation, operate on calculation server, be applied to the monitoring of crack propagation life of turbine rotor, concrete steps are:

The first step: the crack size of turbine rotor is determined in flaw detection:

At steam turbine, open between the turn(a)round of cylinder, adopt ultra-sonic defect detector to determine position, place and the crack size of crackle, crack size refers to minor axis radius a and the major axis radius c of the Ellipse crack of rotor;

Second step: the major principal stress of calculating position, crackle place:

For underbead crack, calculate cold start, warm starting, hot starting, hot start, very hot startup and the 110% nominal operation over speed of rotation test major principal stress of totally five kinds of transient processes, use respectively symbol σ _1c, σ _1w, σ _1h, σ _1rand σ _10srepresent;

The 3rd step: the critical crack size of calculating turbine rotor:

The critical crack size a of turbine rotor i kind transient condition _cicomputing formula be:

$a_{\mathrm{ci}}={\mathrm{\&sigma;}}_{1i}\sqrt{\mathrm{Ma}}$

In formula:

σ _1i---the major principal stress of i kind transient condition

A---Ellipse crack minor axis radius

M---the constant relevant with crack shape parameter Q,

For underbead crack,

For surface crack,

$Q={\&Integral;}_0^{\frac{\mathrm{\&pi;}}{2}}(1-\frac{c^2-a^2}{c^2}{\sin }^2\mathrm{\&theta;})\mathrm{d\&theta;}$

C---Ellipse crack major axis radius

θ---cross the radial line of any point and the angle of transverse on crackle contour

The 4th step: calculate crack propagation life of turbine rotor

The crack propagation life of turbine rotor N of i kind transient condition _ficomputing formula be:

$N_{\mathrm{fi}}=\frac{2}{(m_0-2)C_0{\mathrm{\&sigma;}}_{1i}^{m_0}{M}^{\frac{m_0}{2}}}[\frac{1}{a^{\frac{(m_0-2)}{2}}}-\frac{1}{{a_{\mathrm{ci}}}^{\frac{(m_0-2)}{2}}}]$

In formula:

C ₀, m ₀---rotor material crack expansion test constant;

The 5th step: calculate overspeed test process rotor crack expansion life-span integration loss:

The crack propagation life integration loss E that turbine rotor causes due to overspeed test _f0computing formula be:

$E_{f0}=\frac{n_{\mathrm{os}}}{N_{\mathrm{fos}}}$

In formula:

N _os---overspeed test of steam turbine number of times

N _fos---the crack propagation life in overspeed test process;

The 6th step: calculate turbine rotor propagation of internal cracks life-span integration loss:

Turbine rotor propagation of internal cracks life-span integration loss E _f1computing formula be:

$E_{f1}=\frac{n_c}{N_{\mathrm{fc}}}+\frac{n_w}{N_{\mathrm{fw}}}+\frac{n_h}{N_{\mathrm{fh}}}+\frac{n_r}{N_{\mathrm{fr}}}$

In formula:

N _c---the cold start number of times of actual motion

N _w---the warm starting number of times of actual motion

N _h---the hot starting, hot start number of times of actual motion

N _r---the very hot startup number of times of actual motion

N _fc---crack propagation life in cold start process

N _fw---crack propagation life in warm starting process

N _fh---crack propagation life in hot starting, hot start process

N _fr---crack propagation life in very hot startup process

The 7th step: calculate turbine rotor propagation of internal cracks residual life:

Turbine rotor propagation of internal cracks residual life R _l1computing formula be:

$R_{L1}=\frac{1-E_{f0}-E_{f1}}{e_{y1}}$

In formula:

E _y1---the average annual crack propagation life loss of internal rotor,

M---find crackle calendar year number so far;

The 8th step: control Cracks in Turbine Rotors expansion residual life

If the propagation of internal cracks residue calendar life-span R of turbine rotor _l1or external crack expansion residue calendar life-span R _l2<4, scheme of arrangement overhaul within the year, is overhauled or is changed according to result of detection; If 4 years≤R _l1or R _l2<8, scheme of arrangement overhaul after 1 year but in 4 years, is overhauled or is changed according to result of detection; If 8 years≤R _l1or R _l2<16, in upper once scheduled major overhaul, gives detailed defect detecting test; If R _l1or R _l2>=16 years, according to scheduled major overhaul cycle and the scheduled major overhaul project of the overhaul of the equipments guide rule > > of < < electricity power enterprise arrangement steam turbine;

The 9th step: printout result

Output Cracks in Turbine Rotors is expanded result of calculation and the control measure of residual life, is applied to the Optimal Maintenance of steam turbine.

2. the method for supervising in turbine rotor propagation of internal cracks life-span as claimed in claim 1, it is characterized in that, the concrete steps of described second step are: the mechanical model of setting up the rotational symmetry FEM (finite element) calculation of turbine rotor, adopt existing finite element analysis technology, calculate cold start, warm starting, hot starting, hot start, very hot startup and the 110% nominal operation over speed of rotation test major principal stress of totally five kinds of transient processes; For outside crackle, calculate shutdown at sliding parameters, orderly closedown, force outage and the 110% nominal operation over speed of rotation test major principal stress of totally four kinds of transient processes.

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