CN105526878A - Real-time dynamic measurement method for measuring radial clearance between steam turbine rotor and stator - Google Patents

Abstract

The invention provides a real-time dynamic measurement method for measuring radial clearance between a steam turbine rotor and a stator. The method is characterized in that the method comprises the steps of determining distance measurement devices for radial clearance, determining radial clearance between the rotor and the stator, determining the radial clearance between the rotor and the stator, determining the distance from an emitter to the surface of the rotor, calculating vertical offset amount of the rotor when the center of the rotor shifts, calculating horizontal offset amount of the rotor when the center of the rotor shifts, calculating the rotor offset amount at any position and calculating the radial clearance between the steam turbine rotor and the stator. The method can carry out dynamic measurement on the rotor labyrinth clearance and blade top labyrinth clearance of a running steam turbine accurately and quickly, thereby solving the problem that the measuring error of the radial clearance between the steam turbine rotor and the stator is large and the radial clearance cannot be measured online dynamically and accurately, ensuring safe and economical operation of the machine set and saving halt overhaul time.

Description

A kind of real time dynamic measurement method of radial play between turbine rotor and stator

Technical field

The present invention relates to heat power equipment performance state monitoring and diagnosis field, is the real time dynamic measurement method of radial play between a kind of turbine rotor and stator.

Background technology

Steam turbine is a kind of high-speed rotating machine steam thermal energy being converted to mechanical energy.For keeping not touching mill between steam turbine rotatable parts and stationary parts, must make to leave certain gap between steam turbine rotatable parts and stationary parts.The size of Turbine Flow Path radial play is the important indicator affecting the safe and reliable property of Turbine Flow Path.If this gap is too small, probably cause touching mill between sound, cause steam turbine rotor and stator blade to wear and tear; the work efficiency of unit is reduced, unit failure will be forced time serious to shut down, if excesssive gap; to the leakage losses of steam turbine be increased, the performance driving economy of steam turbine reduces.Therefore, no matter between Turbine Flow Path sound, radial play is the excessive too small operation to unit is all disadvantageous.Obviously, in operation, real time dynamic measurement fast and accurately carries out to radial play between Turbine Flow Path rotor and stator significant for the safety and economic operation of steam turbine.

China number of the edition 23-1251/TH " steam turbine technology " 03 phase in 1997 discloses the people such as Jiang Yaoming " dynamic clearance of turbomachinery an is measured " literary composition, a kind of method measuring radial play between turbomachinery sound is given in literary composition, but first this kind of method need to be connected to by sensor on every blade, carries out static mapping.During kinetic measurement, then need the heat abstractor at probe two ends to add cooling circulating water, guarantee the temperature and pressure tested.Obviously the precision of this kind of method dynamic measurement results is not only by the impact of static mapping, but also is subject to the impact of the heat exchange situation of heat abstractor.In addition, this kind of method surveying work medium mainly for be gas turbine, for steam turbine, because mesolow flow passage component vapor (steam) temperature is lower, its measuring accuracy far can not meet the requirement of steam turbine.

Chinese invention patent application numbers 201210589363.4 proposes " a kind of utilize radial play sensor to obtain discrete axial clearance data equipment and method ", the method needs on stator, to install at least one radial play sensor, in order to collect radial play data to determine axial clearance data.Obvious the method has two obvious defects, and in steam turbine stator, installable number of sensors is limited on the one hand, and can not cover the gamut of differential axially-movable, this will make measuring accuracy reduce.On the other hand, in test process, as long as the data distortion of any one sensor, whole test result precision will be caused to reduce.

Up to now, there is not yet the bibliographical information about the real time dynamic measurement method of radial play between turbine rotor and stator and practical application.

Summary of the invention

In running for existing large-size steam turbine, flow passage component radial play is difficult to the problem realizing accurate real time dynamic measurement; the present invention proposes a kind ofly to carry out to the radial play of steam turbine in running the method that quick, high-precision detection realizes the accurate kinetic measurement in rotor labyrinth clearance and blade tip seal gap; thus detect the running status of current steam turbine more truly; ensure unit safety economical operation, save and shut down the overhaul time.

The technical solution used in the present invention is: a kind of real time dynamic measurement method of radial play between turbine rotor and stator, it is characterized in that: adopt two distance measuring equipments to launch light modulated, by cooperative target reflected back towards receiver, described distance measuring equipment is high-frequency phase formula laser range finder, described cooperative target is corner reflector, and this measuring method comprises the following steps:

1), when setting up turbine rotor center without skew, the model one of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determines radial play between rotor and stator;

2), when setting up turbine rotor center generation any direction skew, the model two of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determines the distance of transmitter to rotor surface;

3) set up turbine rotor when only having transversal displacement, the model three of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, calculate unidirectional rotor offset and unidirectional rotor surface vertical displacement amount when skew occurs rotor center;

4) set up turbine rotor when only having vertical displacement, the model four of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, calculate unidirectional rotor offset and unidirectional rotor surface transversal displacement amount when skew occurs rotor center;

5) the unidirectional rotor offset calculated in described model three and described model four and unidirectional rotor surface displacement amount are substituted in described model two, calculate the rotor eccentricity of described optional position.

Described distance measuring equipment is positioned over outside cylinder, and described cooperative target is installed on described rotor surface.

Described step 1) in, described coordinate is take rotor center as initial point, and two distance measuring equipments lay respectively at the two-dimensional coordinate system on point surface in cylinder horizontal and vertical, and laser emission point A, B are denoted as L along x-axis, y-axis direction to the distance of described rotor surface _xand L _y, rotor without acceptance of persons, friction time laser emission point be denoted as x to the gauged distance of described corner reflector ₀, y ₀, rotor without acceptance of persons, friction time described rotor surface be L to the distance of cylinder body ₀, obtain according to speed, time and range formula wherein Δ t ₁for laser to complete the time of a round trip in x direction, s; Δ t ₂for laser to complete the time of a round trip in y direction, s; C is the light velocity, m/s.

Described step 2) in, the rotor center after being subjected to displacement is O ₂if rotor displacement is any direction and size is e, wherein x ₁for the projection displacement of displacement e in x-axis, y ₁for the projection displacement of displacement e in y-axis; The x direction caused due to curved surface after rotating shaft is subjected to displacement and the additional distance in y direction can be denoted as Δ x, Δ y, and wherein, Δ x is that rotating shaft is at generation y ₁the additional distance caused after vertical displacement, Δ y is that rotating shaft is at generation x ₁the additional distance caused after transversal displacement.

Described step 3) in, by the function x of circle ²+ y ²=r ²try to achieve laser on y direction at epitrochanterian reflection spot y ' ₁for in formula: y ' ₁for laser is at the reflection spot of rotor surface; R is the radius of rotating shaft of steam turbine, m; The gap on y direction is caused to be changed to by the transversal displacement on x direction: Δ y=r-y ' ₁, in formula: y ' ₁for laser is at the reflection spot of rotor surface.

Described step 4) in, rotor causes the gap on x direction to be changed to by the vertical displacement on y direction: Δ x=r-x ' ₁, in formula: x ' ₁for laser is at the reflection spot of rotor surface.

Described step 5) in, by laser emission point A along the x-axis direction to the distance L of described rotor surface _x, rotating shaft generation y ₁the additional distance Δ x caused after vertical displacement and rotor without acceptance of persons, friction time laser emission point to the gauged distance x of described corner reflector ₀the projection displacement x of e in x-axis can be obtained ₁for: L _x-x ₀-Δ x=x ₁, the projection displacement y of e in y-axis ₁for: L _y-y ₀-Δ y=y ₁; Described in inciting somebody to action Δ x=r-x ' ₁substitute into described L _x-x ₀-Δ x=x ₁: $\frac{1}{2}{\mathrm{c\Δt}}_1-(r-\sqrt{r^2-y_1^2})-x_0=x_1,$ Described in inciting somebody to action $L_y=\frac{1}{2}{\mathrm{c\Δt}}_2,y_1^{\′}=\sqrt{r^2-x_1^2},$ Δ y=r-y ' ₁substitute into described L _y-y ₀-Δ y=y ₁? $\frac{1}{2}{\mathrm{c\Δt}}_2-(r-\sqrt{r^2-x_1^2})-y_0=y_1,$ Described in simultaneous $\frac{1}{2}{\mathrm{c\Δt}}_1-(r-\sqrt{r^2-y_1^2})-x_0=x_1$ With try to achieve x ₁and y ₁; Thus the maximal clearance of trying to achieve between turbine rotor and stator and minimum clearance, described maximal clearance is described minimum clearance is

The present invention is according to the test philosophy of high-frequency phase formula laser range finder and feature and adopt two a kind of real time dynamic measurement method of radial play between turbine rotor and stator surveying that chi distance-measuring and positioning method obtains in conjunction with relative coordinate system, and the advantage applies had exists:

1. rely on two high-frequency phase formula laser range finders and motion rotors to set up four relative coordinate systems and adopt and pair to survey chi distance-measuring and positioning method to reflect that rotor is in not position in the same time, realize the non-contact measurement to turbine rotor movement locus in operation, thus reach the quick and precisely real-time dynamically on-line monitoring to running radial play between medium-and-large-sized Turbine Flow Path rotor and stator;

2. compared with the capacitor and inductor distance-finding method most widely used with existing range finding, not only reduce the installation difficulty of measuring sensor in steam turbine inside, and decrease temperature high-pressure steam environment in steam turbine and, on the impact of sensor, substantially increase the precision of measurement; Compared with existing sound ranging method, not only there is the feature that time delay is short, react fast, easy realization, and avoid steam turbine inner high speed steam steam flow to the interference of sound wave, measuring accuracy is largely increased, and the real-time dynamic monitoring to radial play between turbine rotor and stator can be realized;

3. can ensure unit safety economical operation, save and shut down the overhaul time.

Accompanying drawing explanation

When Fig. 1 is turbine rotor center without skew, distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system schematic diagram;

When Fig. 2 is turbine rotor center generation any direction skew, the schematic diagram of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system;

Fig. 3 is turbine rotor center when only there is transversal displacement, the schematic diagram of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system;

Fig. 4 is turbine rotor center when only there is vertical displacement, the schematic diagram of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system.

Embodiment

Below in conjunction with accompanying drawing and enforcement example, the present invention is described in further detail.

With reference to Fig. 1 ~ Fig. 4, the real time dynamic measurement method of radial play between a kind of turbine rotor provided by the invention and stator, comprises following content:

A. link chosen by distance measuring equipment

Choose two high-frequency phase formula laser range finders to measure Turbine Flow Path radial play.The light modulated utilizing transmitter to penetrate by high-frequency phase formula laser range finder realizes range observation by the phase differential of the reflected light of cooperative target reflected back towards receiver.Take a kind ofly can either meet the dispersion that precision can meet again measuring distance and directly survey chi combined method by the laser in combination of two different frequencies measurement clearance respectively, wherein low frequency lasers carries out bigness scale, and high frequency lasers carries out accurate measurement.

Obtaining modulator, to send low frequency be f ₁laser, then wavelength is

${\mathrm{\λ}}_1=\frac{c}{f_1}---(1-1)$

In formula: λ ₁for the wavelength of low frequency laser launched by phase laser distance measurement instrument, m; f ₁for the frequency of low frequency laser launched by phase laser distance measurement instrument, Hz; C is the light velocity, m/s.

In like manner, obtaining modulator, to send high-frequency be f ₂laser, then wavelength is

${\mathrm{\λ}}_2=\frac{c}{f_2}---(1-2)$

In formula: λ ₂for the wavelength of high-frequency laser launched by phase laser distance measurement instrument, m; f ₂for the frequency of high-frequency laser launched by phase laser distance measurement instrument, Hz; C is the light velocity, m/s.

Be received during this period of time from being transmitted at laser, if through n cycle, obtaining the distance of low frequency laser from transmitter to receiver is

L ₁＝λ ₁n(2-1)

In formula: L ₁for the distance of low frequency laser from transmitter to receiver, m; λ ₁for the wavelength of low frequency laser launched by phase laser distance measurement instrument, m; N is the laser cycle.

In like manner, obtaining high-frequency generating laser to the distance of receiver is

L ₂＝λ ₂n(2-2)

In formula: L ₂for the distance of high-frequency laser from transmitter to receiver, m; λ ₂for the wavelength of high-frequency laser launched by phase laser distance measurement instrument, m; N is the laser cycle.

If laser is after experience round trip less than n cycle and when being greater than n-1 cycle, based on obtaining the distance of low frequency laser from transmitter to receiver is

L′ ₁＝λ ₁(n+Δn)(3-1)

In formula: L ' ₁for the distance of low frequency laser from transmitter to receiver, m; λ ₁for the wavelength of low frequency laser launched by phase laser distance measurement instrument, m; Δ n is the difference in cycle; N is the laser cycle.

In like manner, obtaining the distance of high-frequency laser from transmitter to receiver is

L′ ₂＝λ ₂(n+Δn)(3-2)

In formula: L ' ₂for high-frequency generating laser is to the distance of receiver, m; λ ₂for the wavelength of high-frequency laser launched by phase laser distance measurement instrument, m; Δ n is the difference in cycle; N is the laser cycle.

B. when turbine rotor center is without skew, the foundation of the model one of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determine radial play link between rotor and stator:

As shown in Figure 1, pick-up unit is positioned over outside steam turbine by the present invention, do not consider the impact of the axial displacement of rotor, to intercept the inner a certain vertical plane of steam turbine, distance measuring equipment, cooperative target, rotor and cylinder body are based upon with rotor center be initial point xy two-dimensional coordinate system in.

Rotor without skew time its surface with cylinder body can see two concentric circless as, if between the two distance be L ₀, x ₀, y ₀represent respectively rotor without acceptance of persons, friction time rotor surface distance detection device A, B gauged distance, namely rotor center is when without skew, maximum between rotor and stator, minimum radial distance is equal, can be expressed as

X _max＝X _min＝x ₀＝y ₀＝L ₀(4)

In formula: X _maxfor the ultimate range of radial play between turbine rotor and stator, m; X _minfor the minor increment of radial play between turbine rotor and stator, m; x ₀for rotor without acceptance of persons, friction time distance detection device A gauged distance, m; y ₀for rotor without acceptance of persons, friction time distance detection device B gauged distance, m; L ₀for turbine rotor center is without when offseting, radial play between rotor and stator, m.

C. when there is any direction skew in turbine rotor center, the foundation of the model two of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determine the distance link of transmitter to rotor surface:

As shown in Figure 2, when in running, vibration and skew occur the rotor of unit, the rotor reference position initial relative to it is subjected to displacement, then rotor center changes, if the rotor center after being subjected to displacement is O ₂if rotor displacement is any direction and size is e.Wherein x ₁for the projection displacement of displacement e in x-axis, y ₁for the projection displacement of displacement e in y-axis.Because rotating shaft surface is circular curved surface, thus the additional distance caused due to curved surface after rotating shaft is subjected to displacement we be denoted as Δ x, Δ y.Δ x is that rotating shaft is at generation y ₁the additional distance caused after vertical displacement, Δ y is that rotating shaft is at generation x ₁the additional distance caused after transversal displacement.

After survey chi is determined, subtract formula (2-1) by formula (3-1) and distance be converted into apart from must the distance of low frequency laser from transmitter to receiver be

$L_1^{\′\′}=\frac{1}{2}{\mathrm{\λ}}_1\mathrm{\Δ}n---(5-1)$

In formula: L " ₁for the distance of low frequency laser from transmitter to receiver, m; λ ₁for the wavelength of low frequency laser launched by phase laser distance measurement instrument, m; Δ n is the difference in cycle.

In like manner, after survey chi is determined, subtract formula (2-2) by formula (3-2) and distance be converted into apart from must the distance of high-frequency laser from transmitter to receiver be

$L_2^{\′\′}=\frac{1}{2}{\mathrm{\λ}}_2\mathrm{\Δ}n---(5-2)$

In formula: L " ₂for the distance of high-frequency laser from transmitter to receiver, m; λ ₂for the wavelength of high-frequency laser launched by phase laser distance measurement instrument, m; Δ n is the difference in cycle.

Following formula is had to set up for the known light velocity and frequency

c＝λf(6)

In formula: c is the light velocity, m/s; λ is the wavelength that high-frequency phase formula laser range finder launches laser, m; F is the frequency that high-frequency phase formula laser range finder launches laser, Hz.

The time that laser completes a stroke is

In formula: Δ t is the time that laser completes a stroke, s; F is the frequency that high-frequency phase formula laser range finder launches laser, Hz; for the phase differential of transmitter and receiver, rad/s.

By formula (7), formula (6) substitutes into formula (5-1) and (5-2) can by phase differential be scaled time Δ t, then now obtaining transmitter Emission Lasers in conjunction with the test philosophy of phase laser distance measurement method to the distance on rotating shaft surface is

$L_x=\frac{1}{2}{\mathrm{c\Δt}}_1---\left(8\right)$

$L_y=\frac{1}{2}{\mathrm{c\Δt}}_2---\left(9\right)$

In formula: L _xthe ray of rotor center and the transmitter distance to rotating shaft surface is pointed to, m for pointing out outbreak from A; L _ythe ray of rotor center and the transmitter distance to rotating shaft surface is pointed to, m for pointing out outbreak from B; C is the light velocity, m/s; Δ t ₁for laser to complete the time of a round trip in x direction, s; Δ t ₂for laser to complete the time of a round trip in y direction, s.

D., when turbine rotor only has transversal displacement, the foundation of the model three of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, calculates unidirectional rotor offset and unidirectional rotor surface vertical displacement amount link when skew occurs rotor center:

Due to rotor vibrating, eccentric time its transversal displacement and vertical displacement be respectively projection displacement x ₁, y ₁, Δ x, Δ y are independently asked for, first suppose that rotor is along x-axis displacement x ₁and non-displacement in y-direction, so by the function x of circle in mathematics ²+ y ²=r ²try to achieve laser on y direction at epitrochanterian reflection spot y ' ₁.

When rotor is x in x direction side-play amount ₁time, the value on y direction is

$y_1^{\′}=\sqrt{r^2-x_1^2}---\left(10\right)$

In formula: y ' ₁for laser is at the reflection spot of rotor surface; R is the radius of rotating shaft of steam turbine, m; x ₁for the projection displacement of displacement e in x-axis, m.

The gap on y direction is caused to be changed to by the transversal displacement on x direction:

Δy＝r-y′ ₁(11)

In formula: Δ y is due to the additional distance that curved surface causes after turbine rotor is subjected to displacement, m; R is the radius of rotating shaft of steam turbine, m; Y ' ₁for laser is at the reflection spot of rotor surface.

E. when turbine rotor only has vertical displacement, the model four of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system is set up, and calculates unidirectional rotor offset and rotor surface transversal displacement amount link when skew occurs rotor center:

As shown in Figure 4, by the method asking for rotor surface vertical displacement amount in steps d, in like manner calculate rotor surface transversal displacement amount, rotor causes the gap on x direction to be changed to by the vertical displacement on y direction

$x_1^{\′}=\sqrt{r^2-y_1^2}---\left(12\right)$

Δx＝r-x′ ₁(13)

In formula: x ' ₁for laser is at the reflection spot of rotor surface; y ₁for the projection displacement of displacement e in y-axis, m; R is the radius of rotating shaft of steam turbine, m; Due to the additional distance that curved surface causes after Δ x turbine rotor is subjected to displacement, m.

F. the unidirectional rotor offset calculated in model three and model four and unidirectional rotor surface displacement amount are substituted in model two, calculate the rotor eccentricity link of optional position:

When rotor deflection is to optional position, it all can resolve into again along y-axis deflection after x-axis deflection, and the rotor deflection amount therefore during optional position is the stack result of model three and model four.Distance L after known rotor bias _x, additional displacement Δ x and gauged distance x ₀obtain the projection displacement x of e in x-axis ₁for

L _x-x ₀-Δx＝x ₁(14)

In formula: L _xthe ray of rotor center and the transmitter distance to rotating shaft surface is pointed to, m for pointing out outbreak from A; x ₀for rotor without acceptance of persons, friction time distance detection device A gauged distance, m; Δ x is due to the additional distance that curved surface causes after turbine rotor generation vertical displacement, m; x ₁for the projection displacement of displacement e in x-axis, m.

In like manner, the projection displacement y of e in y-axis ₁for:

L _y-y ₀-Δy＝y ₁(15)

In formula: L _ythe ray of rotor center and the transmitter distance to rotating shaft surface is pointed to, m for pointing out outbreak from B two; y ₁be respectively the projection displacement of rotor in cylinder on y direction, m; y ₀respectively represent rotor without acceptance of persons, friction time distance detection device B gauged distance, m; Δ y is the additional distance caused by curved surface after turbine rotor generation transversal displacement, m.

Obtain final after arranging to formula (8), formula (12), formula (13) substitution formula (14)

$\frac{1}{2}{\mathrm{c\Δt}}_1-(r-\sqrt{r^2-y_1^2})-x_0=x_1---\left(16\right)$

In formula: c is the light velocity, m/s; Δ t ₁for laser to complete the time of a round trip in x direction, s; R is the radius of rotating shaft of steam turbine, m; y ₁for the projection displacement of e in y-axis, m; x ₁for the projection displacement of e in x-axis, m; x ₀for rotor without acceptance of persons, friction time distance detection device A gauged distance, m.

In like manner formula (9), formula (10), formula (11) are substituted into formula (15) and obtain after arranging

$\frac{1}{2}{\mathrm{c\Δt}}_2-(r-\sqrt{r^2-x_1^2})-y_0=y_1---\left(17\right)$

In formula: c is the light velocity, m/s; Δ t ₂for laser to complete the time of a round trip in y direction, s; R is the radius of rotating shaft of steam turbine, m; y ₁for the projection displacement of e in y-axis, m; x ₁for the projection displacement of e in x-axis, m; y ₀for rotor without acceptance of persons, friction time distance detection device B gauged distance, m.

Simultaneous formula (16) and formula (17), try to achieve the projection displacement x of e in x-axis and y-axis ₁and y ₁.

Obtained by Pythagorean theorem

$e=\sqrt{x_1^2+y_1^2}---\left(18\right)$

In formula: e is the offset at turbine rotor center, m; y ₁for the projection displacement of e in y-axis, m; x ₁for the projection displacement of e in x-axis, m.

G. the calculating link of radial play between turbine rotor and stator:

Due to rotor without acceptance of persons with the gauged distance x under Vibration Condition ₀=y ₀=L ₀, for the maximal clearance X between turbine rotor and stator _maxfor

X _max＝L ₀+e(19)

In formula: X _maxfor the radial play maximal value between turbine rotor and stator, m; L ₀for turbine rotor center is without when offseting, radial play between rotor and stator, m; E is the offset at turbine rotor center, m.

Minimum clearance X between turbine rotor and stator _minfor

X _min＝L ₀-e(20)

In formula: X _minfor the smallest radial gap width between turbine rotor and stator, m; L ₀for turbine rotor center is without when offseting, radial play between rotor and stator, m; E is the offset at turbine rotor center, m.

Above formula (19) and formula (20) are respectively the minimum and maximum value of radial play between turbine rotor and stator.

Calculated examples: now carry out example calculation for above embodiment, desired data is as following table 1.

The real time dynamic measurement method desired data table of table 1 radial play between turbine rotor and stator

Cylinder body radius	200mm	The radius of rotating shaft	120mm
				Thick dipstick metering journey	1000-1mm	Thin dipstick metering journey	150-0.15mm
Thick chi phase differential (1)	5.027rad	Thin chi phase differential (1)	3.3565rad
				Thick chi phase differential (2)	5.027rad	Thin chi phase differential (2)	3.3577rad

A determines the distance measuring equipment of radial play:

Choose two high-frequency phase formula laser range finders to measure Turbine Flow Path radial play.The light modulated utilizing transmitter to penetrate by high-frequency phase formula laser range finder realizes range observation by the phase differential of the reflected light of cooperative target reflected back towards receiver.The present invention takes a kind ofly can either meet direct survey chi combined method that precision can meet again the dispersion of measuring distance by the laser in combination of two different frequencies measurement clearance respectively, and wherein low frequency lasers carries out bigness scale, and high frequency lasers carries out accurate measurement.

Wherein, modulator sends the wavelength of low frequency laser and is

${\mathrm{\λ}}_1=\frac{3\×{10}^8}{150\×{10}^6}=2m---(1-1)$

In formula: λ ₁the wavelength of low frequency laser launched by phase laser distance measurement instrument, m.

The wavelength that modulator sends high-frequency laser is

${\mathrm{\λ}}_2=\frac{3\×{10}^8}{1000\×{10}^6}=0.3m---(1-2)$

In formula: λ ₂the wavelength of high-frequency laser launched by phase laser distance measurement instrument, m.

From Laser emission to received during this period of time in, if through n cycle, the distance of low frequency laser from transmitter to receiver is

L ₁＝2n(2-1)

In formula: L ₁for the distance of low frequency laser from transmitter to receiver, m; N is the laser cycle.

The distance of high-frequency laser from transmitter to receiver is

L ₂＝0.3n(2-2)

In formula: L ₂for the distance of high-frequency laser from transmitter to receiver, m; N is the laser cycle.

If laser is after experience round trip less than n cycle and when being greater than n-1 cycle, by obtaining the distance of low frequency laser from transmitter to receiver is

L′ ₁＝2(n+Δn)(3-1)

In formula: L ' ₁for the distance of low frequency laser from transmitter to receiver, m; Δ n is the difference in cycle; N is the laser cycle.

The distance of high-frequency laser from transmitter to receiver is

L′ ₂＝0.3(n+Δn)(3-2)

In formula: L ' ₂for the distance of high-frequency laser from transmitter to receiver, m; Δ n is the difference in cycle; N is the laser cycle.

When b sets up turbine rotor center without skew, the model one of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determine radial play between rotor and stator:

Pick-up unit is positioned over outside steam turbine by the present invention, and does not consider the impact of the axial displacement of rotor.As shown in Figure 1.To intercept the inner a certain vertical plane of steam turbine, distance measuring equipment, cooperative target, rotor and cylinder body are based upon with rotor center be initial point xy two-dimensional coordinate system in.Rotor center when what now coordinate origin was corresponding is without acceptance of persons, is denoted as O ₁.A, B two distance measuring equipments lay respectively at cylinder and vertically and in level divide surface, and it comprises generating laser and receiver, and it is constant all the time that generating laser sends directions of rays.A, b are reception and the reflection spot of cooperative target and laser, are arranged on the circumferential surface of measured rotor.Laser emission point A, B are denoted as L along x-axis, y-axis direction to the distance of rotor surface _xand L _y.L time in rotor friction and without acceptance of persons _xand L _yoverlap with x-axis, y-axis.

Rotor center is when without skew, and its surface can see two concentric circless as, if distance is between the two L with cylinder body ₀.X ₀, y ₀represent respectively rotor without acceptance of persons, friction time laser emission point to the gauged distance of corner reflector, namely rotor center is without when offseting, maximum between rotor and stator, minimum radial distance is equal, can be expressed as

X _max＝X _min＝x ₀＝y ₀＝L ₀＝80mm(4)

In formula: X _maxfor the ultimate range of radial play between turbine rotor and stator, m; X _minfor the minor increment of radial play between turbine rotor and stator, m; x ₀for rotor without acceptance of persons, friction time distance detection device A gauged distance, m; y ₀for rotor without acceptance of persons, friction time distance detection device B gauged distance, m; L ₀for turbine rotor center is without when offseting, radial play between rotor and stator, m.

When c sets up turbine rotor center generation any direction skew, the model two of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determine the distance of transmitter to rotor surface:

As shown in Figure 2, when vibration and skew occur turbine rotor in running, the rotor center reference position initial relative to it offsets, if the rotor center after being subjected to displacement is O ₂if rotor displacement is any direction and size is e.Wherein x ₁for the projection displacement of displacement e in x-axis, y ₁for the projection displacement of displacement e in y-axis.Because rotating shaft surface is circular curved surface, so the additional distance caused due to curved surface after rotating shaft is subjected to displacement can be denoted as Δ x, Δ y.Wherein, Δ x is that rotating shaft is at generation y ₁the additional distance caused after vertical displacement, Δ y is that rotating shaft is at generation x ₁the additional distance caused after transversal displacement.

After survey chi is determined, subtract formula (2-1) by formula (3-1), formula (3-2) subtracts formula (2-2) and distance is converted into distance must

$L_1^{\′\′}=\frac{1}{2}\×2\mathrm{\Δ}n---(5-1)$

In formula: L " ₁for the distance of low frequency laser from transmitter to receiver, m; Δ n is the difference in cycle.

$L_2^{\′\′}=\frac{1}{2}\×0.3\mathrm{\Δ}n---(5-2)$

In formula: L " ₂for the distance of high-frequency laser from transmitter to receiver, m; Δ n is the difference in cycle.

Following formula is had to set up for the known light velocity and frequency

c＝2×150×10 ⁶＝0.3×1000×10 ⁶m/s(6)

In formula: c is the light velocity, m/s.

By phase differential be scaled time Δ t, then

For thick chi, the time completing a stroke at x direction laser is

For thick chi, the time completing a stroke at y direction laser is

For thin chi, the time completing a stroke at x direction laser is

For thin chi, the time completing a stroke at y direction laser is

Thick chi records distance and is turbine rotor center without when offseting, radial play between rotor and stator:

$L_{x\left(0\right)}=\frac{1}{2}\×3\×{10}^8\×5.344\×{10}^{-10}=0.080m=80mm---(8-1)$

$L_{y\left(0\right)}=\frac{1}{2}\×3\×{10}^8\×5.344\×{10}^{-10}=0.080m=80mm---(9-1)$

In formula: L _{x (0)}and L _{y (0)}for turbine rotor center without skew time, in the radial play in x direction and y direction between rotor and stator, mm.

Thin chi records distance

$L_x=\frac{1}{2}\×3\×{10}^8\×5.342\×{10}^{-10}=0.08013m=80.13mm---(8-2)$

$L_y=\frac{1}{2}\×3\×{10}^8\×5.344\×{10}^{-10}=0.08016m=80.16mm---(9-2)$

In formula: L _xand L _yfor from A, B two point do respectively and point to two rays of rotor center and the transmitter distance to rotating shaft surface, mm.

D sets up turbine rotor when only having transversal displacement, the model three of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, calculates unidirectional rotor offset and unidirectional rotor surface vertical displacement amount when skew occurs rotor center:

Due to rotor vibrating, eccentric time its transversal displacement and vertical displacement be respectively projection displacement x ₁, y ₁, Δ x, Δ y are independently asked for, first suppose that rotor is along x-axis displacement x ₁and non-displacement in y-direction, so by the function x of circle in mathematics ²+ y ²=r ²try to achieve laser on y direction at epitrochanterian reflection spot y ' ₁.

When rotor is x in x direction side-play amount ₁time, the value on y direction is

$y_1^{\′}=\sqrt{{120}^2-x_1^2}---\left(10\right)$

In formula: y ' ₁for laser is at the reflection spot of rotor surface; x ₁for the projection displacement of displacement e in x-axis, m.

The gap on y direction is caused to be changed to by the transversal displacement on x direction

Δy＝120-y′ ₁(11)

In formula: Δ y is due to the additional distance that curved surface causes after turbine rotor is subjected to displacement, m; Y ' ₁for laser is at the reflection spot of rotor surface.

E sets up turbine rotor when only having vertical displacement, the model four of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, calculates unidirectional rotor offset and unidirectional rotor surface transversal displacement amount when skew occurs rotor center:

As shown in Figure 4, by the method asking for rotor surface vertical displacement amount in step (d), calculate rotor surface transversal displacement amount, rotor causes the gap on x direction to be changed to by the vertical displacement on y direction:

$x_1^{\′}=\sqrt{{120}^2-y_1^2}---\left(12\right)$

In formula: x ' ₁for laser is at the reflection spot of rotor surface; y ₁for the projection displacement of displacement e in y-axis, m.

Δx＝120-x′ ₁(13)

In formula: due to the additional distance that curved surface causes after Δ x turbine rotor is subjected to displacement, m; X ' ₁for laser is at the reflection spot of rotor surface.

The unidirectional rotor offset calculated in model three and model four and unidirectional rotor surface displacement amount substitute in model two by f, calculate the rotor eccentricity of optional position:

When rotor deflection is to optional position, it all can resolve into again along y-axis deflection after x-axis deflection, and the rotor deflection amount therefore during optional position is the result that model three and model four superpose.Distance L after known rotor bias _x, additional displacement Δ x and gauged distance x ₀obtain the projection displacement x of e in x-axis ₁for

L _x-80-Δx＝x ₁(14)

In formula: L _xthe ray of rotor center and the transmitter distance to rotating shaft surface is pointed to, m for doing from A point; Δ x is due to the additional distance that curved surface causes after turbine rotor generation vertical displacement, m; x ₁for the projection displacement of displacement e in x-axis, m.

In like manner, the projection displacement y of e in y-axis ₁for

L _y-80-Δy＝y ₁(15)

In formula: L _ythe ray of rotor center and the transmitter distance to rotating shaft surface is pointed to, m for doing from B two point; y ₁for the projection displacement of rotor in cylinder on y direction, m; Δ y is due to the additional distance that curved surface causes after turbine rotor generation transversal displacement, m.

Obtain final after arranging to formula (8-2), formula (12), formula (13) substitution formula (14)

$80.13-(120-\sqrt{{120}^2-y_1^2})-80=x_1---\left(16\right)$

In formula: x ₁for the projection displacement of e in x-axis, m; y ₁for the projection displacement of e in y-axis, m.

In like manner formula (9-2), formula (10), formula (11) are substituted into formula (15) and obtain after arranging

$80.16-(120-\sqrt{{120}^2-x_1^2})-80=y_1---\left(17\right)$

In formula: y ₁for the projection displacement of e in y-axis, m; x ₁for the projection displacement of e in x-axis, m.

Simultaneous formula (16) and formula (17), can try to achieve the projection displacement x of e in x-axis ₁for 0.16mm, try to achieve the projection displacement y of e in y-axis ₁for 0.13mm.

Obtained by Pythagorean theorem

$e=\sqrt{{0.16}^2+{0.13}^2}=0.206mm---\left(18\right)$

In formula: e is the offset at turbine rotor center, mm.

The calculating of radial play between g turbine rotor and stator:

Due to rotor without acceptance of persons with the gauged distance x under Vibration Condition ₀=y ₀=L ₀, for the maximal clearance between turbine rotor and stator be

X _max＝80+0.206＝80.206mm(19)

In formula: X _maxfor the radial play maximal value between turbine rotor and stator, mm.

For the minimum clearance between turbine rotor and stator be

X _min＝80-0.206＝79.794mm(20)

In formula: X _minfor the smallest radial gap width between turbine rotor and stator, mm.

Claims (7)

1. the real time dynamic measurement method of a radial play between turbine rotor and stator, it is characterized in that: adopt two distance measuring equipments to launch light modulated, by cooperative target reflected back towards receiver, described distance measuring equipment is high-frequency phase formula laser range finder, described cooperative target is corner reflector, and this measuring method comprises the following steps:

1), when setting up turbine rotor center without skew, the model one of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determines radial play between rotor and stator;

2), when setting up turbine rotor center generation any direction skew, the model two of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, determines the distance of transmitter to rotor surface;

3) set up turbine rotor when only having transversal displacement, the model three of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, calculate unidirectional rotor offset and unidirectional rotor surface vertical displacement amount when skew occurs rotor center;

4) set up turbine rotor when only having vertical displacement, the model four of distance measuring equipment, cooperative target, rotor and cylinder body relative tertiary location coordinate system, calculate unidirectional rotor offset and unidirectional rotor surface transversal displacement amount when skew occurs rotor center;

5) the unidirectional rotor offset calculated in described model three and described model four and unidirectional rotor surface displacement amount are substituted in described model two, calculate the rotor eccentricity of described optional position.

2. the real time dynamic measurement method of radial play between turbine rotor according to claim 1 and stator, it is characterized in that: described distance measuring equipment is positioned over outside cylinder, described cooperative target is installed on described rotor surface.

3. the real time dynamic measurement method of radial play between turbine rotor according to claim 1 and stator, it is characterized in that: described step 1) in, described coordinate is take rotor center as initial point, two distance measuring equipments lay respectively at the two-dimensional coordinate system on point surface in cylinder horizontal and vertical, and laser emission point A, B are denoted as L along x-axis, y-axis direction to the distance of described rotor surface _xand L _y, rotor without acceptance of persons, friction time laser emission point be denoted as x to the gauged distance of described corner reflector ₀, y ₀, rotor without acceptance of persons, friction time described rotor surface be L to the distance of cylinder body ₀, obtain according to speed, time and range formula wherein Δ t ₁for laser to complete the time of a round trip in x direction, s; Δ t ₂for laser to complete the time of a round trip in y direction, s; C is the light velocity, m/s.

4. the turbine rotor according to claim 1 or 3 and the real time dynamic measurement method of radial play between stator, is characterized in that: described step 2) in, the rotor center after being subjected to displacement is O ₂if rotor displacement is any direction and size is e, wherein x ₁for the projection displacement of displacement e in x-axis, y ₁for the projection displacement of displacement e in y-axis; The x direction caused due to curved surface after rotating shaft is subjected to displacement and the additional distance in y direction can be denoted as Δ x, Δ y, and wherein, Δ x is that rotating shaft is at generation y ₁the additional distance caused after vertical displacement, Δ y is that rotating shaft is at generation x ₁the additional distance caused after transversal displacement.

5. the real time dynamic measurement method of radial play between turbine rotor according to claim 1 and stator, is characterized in that: described step 3) in, by the function x of circle ²+ y ²=r ²try to achieve laser on y direction at epitrochanterian reflection spot y ' ₁for in formula: y ' ₁for laser is at the reflection spot of rotor surface; R is the radius of rotating shaft of steam turbine, m; The gap on y direction is caused to be changed to by the transversal displacement on x direction: Δ y=r-y ' ₁, in formula: y ' ₁for laser is at the reflection spot of rotor surface.

6. the real time dynamic measurement method of radial play between turbine rotor according to claim 1 and stator, is characterized in that: described step 4) in, rotor causes the gap on x direction to be changed to by the vertical displacement on y direction: Δ x=r-x ' ₁, in formula: x ' ₁for laser is at the reflection spot of rotor surface.

7. the real time dynamic measurement method of radial play between turbine rotor according to claim 1 and stator, is characterized in that: described step 5) in, by laser emission point A along the x-axis direction to the distance L of described rotor surface _x, rotating shaft generation y ₁the additional distance Δ x caused after vertical displacement and rotor without acceptance of persons, friction time laser emission point to the gauged distance x of described corner reflector ₀the projection displacement x of e in x-axis can be obtained ₁for: L _x-x ₀-Δ x=x ₁, the projection displacement y of e in y-axis ₁for: L _y-y ₀-Δ y=y ₁; Described in inciting somebody to action Δ x=r-x ' ₁substitute into described L _x-x ₀-Δ x=x ₁: $\frac{1}{2}{\mathrm{c\Δt}}_1-(r-\sqrt{r^2-y_1^2})-x_0=x_1,$ Described in inciting somebody to action $L_y=\frac{1}{2}{\mathrm{v\Δt}}_2,y_1^{\′}=\sqrt{r^2-x_1^2},$ Δ y=r-y ' ₁substitute into described L _y-y ₀-Δ y=y ₁? $\frac{1}{2}{\mathrm{c\Δt}}_2-(r-\sqrt{r^2-x_1^2})-y_0=y_1,$ Described in simultaneous $\frac{1}{2}{\mathrm{c\Δt}}_1-(r-\sqrt{r^2-y_1^2})-x_0=x_1$ With try to achieve x ₁and y ₁; Thus the maximal clearance of trying to achieve between turbine rotor and stator and minimum clearance, described maximal clearance is described minimum clearance is