CN115493702A - Turbine blade radiation temperature measuring device and temperature measuring method thereof - Google Patents
Turbine blade radiation temperature measuring device and temperature measuring method thereof Download PDFInfo
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- G01J5/00—Radiation pyrometry, e.g. infrared or optical thermometry
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Abstract
The invention provides a turbine blade radiation temperature measuring device and a temperature measuring method thereof, wherein the device comprises: the device comprises a beam deflection device, a first detector device, a second detector device and a third detector device; the radiation beam emitted by the turbine blade enters the beam deflection device, passes through the beam deflection device and then enters the first dichroic mirror to be divided into a first beam and a second beam; the first light beam is incident into a first detector device to obtain a radiation signal under a first wavelength; the third light beam is incident into a second detector device to obtain a radiation signal under a second wavelength; the fourth light beam is incident into a third detector device to obtain a radiation signal under a third wavelength; and distinguishing the turbine blade target surface radiation signal and the environment surface radiation signal in the three radiation signals, and inverting the temperature of the target position on the turbine blade after environment reflection energy correction. The invention can effectively reduce the measurement error.
Description
Technical Field
The invention relates to the technical field of radiation temperature measurement, in particular to a turbine blade radiation temperature measurement device and a temperature measurement method thereof.
Background
Aircraft engines are the most important core part of airplanes, and turbine blades are often required to work under high-temperature and high-pressure working conditions when the aircraft engines are guaranteed to run at high performance and high efficiency. In order to avoid damage of high-temperature environment, the surface of the turbine blade is coated with a thermal barrier coating, so that the working temperature of the turbine blade is increased and even exceeds the melting point of the material of the turbine blade, but the thermal barrier coating is easy to fall off due to long-term high-load work, so that the blade is easy to be damaged by high temperature, and the flight safety is threatened. Therefore, the temperature distribution of the turbine blade is measured, the turbine blade can be ensured to work in a safe temperature range, and hidden dangers can be found in time when the thermal barrier coating is damaged. In addition, during the development and testing of aircraft engines, critical data can be provided for the analysis of the operating conditions of the blades and the development of the engines by accurately measuring the surface temperature distribution of the turbine blades.
The temperature measurement technology is mainly divided into a contact temperature measurement technology and a non-contact temperature measurement technology. The contact type temperature measuring method of the aviation turbine blade mainly comprises a thermocouple method and a temperature indicating paint method: although the thermocouple method has accurate temperature measurement, the installation is troublesome and the adhesion is poor; the temperature indicating paint method can measure the position which is difficult to measure by the thermocouple, but the precision is low, the parts are required to be disassembled for interpretation, and the temperature of the turbine blade is difficult to monitor in real time. The radiation thermometry provides an effective non-contact thermometry method for measuring the temperature distribution of the turbine blade, and the method is based on the Planck radiation theory and measures the thermal radiation of the target surface by a radiation pyrometer to obtain the target temperature. However, in the temperature measurement of turbine blades, radiation thermometry has two main problems: firstly, the emissivity of the surface of the turbine blade is changed along with the increase of working time, and meanwhile, the emissivity of the surface of the turbine blade is also changed by the temperature of the surface of the turbine blade; the second problem is the influence of environmental radiation, when the turbine blade works in a high-temperature environment and the pyrometer measures radiation from the turbine blade, the environmental radiation emitted by the turbine blade and the thermal radiation of the blade enter the pyrometer together, so that the temperature of the obtained turbine blade is higher than the actual temperature, and a non-negligible measurement error is brought. The existing turbine blade temperature measuring instrument on the market at present is mainly a single-band temperature measuring method, and the temperature measuring precision of the method can be influenced by surface emissivity and background radiation. Therefore, the influence of surface emissivity and background radiation is solved, the temperature of the turbine blade is accurately measured, and the method has very important significance for monitoring the running safety of the engine and researching and developing the engine.
Disclosure of Invention
In view of the above problems, the present invention provides a turbine blade radiation temperature measurement device and a temperature measurement method thereof, wherein radiation energy of a plurality of position points of a turbine blade in three different wave bands and environmental energy data acquired by the three wave bands are acquired and substituted into an error function of a radiation temperature measurement method, a temperature initial value selected by step length is substituted into a genetic algorithm to divide a temperature working range of the turbine blade, a temperature value is taken as an initial value in each temperature range to be solved, and finally all the obtained results are compared to obtain a minimum error function value and a corresponding temperature, which is regarded as a true temperature of the surface of the turbine blade. The method can realize the radiation temperature inversion of the turbine blade with unknown emissivity in a radiation environment, does not need to predict an emissivity model of the blade while correcting the influence of environmental radiation, and can effectively reduce measurement errors.
In order to realize the purpose, the invention adopts the following specific technical scheme:
the invention provides a turbine blade radiation temperature measurement method, which utilizes a turbine blade radiation temperature measurement device to realize temperature measurement, and the temperature measurement device comprises: the device comprises a light beam deflection device, two dichroic mirrors, a first detector device, a second detector device and a third detector device;
the radiation beam emitted by the turbine blade enters the beam deflection device, passes through the beam deflection device and then enters the first dichroic mirror to be divided into a first beam and a second beam;
the first light beam is incident into a first detector device to obtain a radiation signal under a first wavelength; the second light beam is incident to the second dichroic mirror and is divided into a third light beam and a fourth light beam; the third light beam is incident into a second detector device to obtain a radiation signal under a second wavelength; the fourth light beam is incident into a third detector device to obtain a radiation signal under a third wavelength;
distinguishing a turbine blade target surface radiation signal and an environment surface radiation signal in the three radiation signals, and inverting the temperature of a target position on the turbine blade after environment reflection energy correction;
the method comprises the following steps:
s1, establishing a radiation model, and calculating a radiation signal at any position point on a turbine blade through the radiation model;
S(λ l ，T i )＝ε b (λ l ，T i )S B (λ l ，T i )+[1-ε b (λ l ，T i )]S e (λ l ，T i )+S D (λ l )
wherein the content of the first and second substances,
S(λ l ，T i ) Is the i-th position point on the turbine blade at the wavelength lambda l Measuring the resulting radiation signal;
ε b (λ l ，T i ) Is the i-th position point at the wavelength λ l The emissivity of (d);
S B (λ l ，T i ) Is to measure the same temperature of the black body as the turbine blade at the wavelength lambda by a pyrometer l A level output signal;
S e (λ l ，T i ) Is received by a pyrometer at the ith position of the turbine blade at a wavelength lambda i A level signal resulting from an infrared radiation of the premises in equal amounts to the ambient radiation;
S D (λ l ) Is detector noise;
s2, collecting radiation signals of the surface of the turbine blade to respectively obtain radiation S (lambda) of the target surface of the turbine blade at three wavelengths l ，T i ) And ambient surface radiation S e (λ l ，T i ) And respectively substituting the two into an error function of a radiation temperature measurement method:
wherein l =1,2,3; i =1,2,3;
s3, setting a preset step length, dividing the actual working temperature range of the turbine blade to obtain a divided region endpoint temperature value T 1b 、T 2b 、T 3b … as initial values are substituted into the error function in step S3, and a genetic algorithm is used to solve error function values and corresponding temperature values corresponding to the initial values of different temperatures;
and S4, taking the temperature value corresponding to the error minimum value obtained by calculating the error function as the real temperature of the surface of the target point on the turbine blade.
Preferably, the beam deflecting means comprises: a reflector, a condenser and a collimator; the reflector is used for realizing the swinging action;
the radiation beam is reflected by the reflector and then converged to a primary image surface by the condenser, and a field diaphragm or an optical fiber is arranged at the primary image surface;
the radiation beam passes through the field diaphragm or the optical fiber and then enters the first dichroic mirror after being collimated by the collimating mirror.
Preferably, the size of the field stop diameter determines the size of the object side surface;
the size of the optical fiber core diameter determines the size of the object side surface.
Preferably, the first detector arrangement comprises: the device comprises a first optical filter, a first focusing lens and a first detector;
the first light beam is filtered by a first optical filter to obtain a light beam under a first wavelength, and the light beam is focused to a target surface of a first detector through a first focusing mirror;
the second detector arrangement includes: the second optical filter, the second focusing mirror and the second detector;
the third light beam is filtered by a second optical filter to obtain a light beam under a second wavelength, and the light beam is focused to a target surface of a second detector through a second focusing mirror;
the third detector arrangement includes: a third optical filter, a third focusing mirror and a third detector;
and the fourth light beam is filtered by a third optical filter to obtain a light beam under a third wavelength, and is focused to the target surface of a third detector through a third focusing lens.
Preferably, the method further comprises a preprocessing step S0 of calibrating the three detector devices by adopting a high-temperature black body to obtain a relation S of the black body temperature and three wavelength signals B (λ l ，T i ) (l =1,2,3; i =1,2,3) and detector noise S D (λ l )(l＝1，2，3)。
Preferably, the emissivity ε b (λ l ，T i ) Set to be linear with temperature:
ε b (λ l ，T i )＝ε b (λ l ，T 1 )[1+k l (T i -T 1 )]。
compared with the prior art, the method comprises the steps of collecting the radiation energy of a plurality of position points of the turbine blade in three different wave bands and the environmental energy data collected by the three wave bands, substituting the radiation energy into an error function of a radiation thermometry method, substituting a temperature initial value selected by step-by-step length into a genetic algorithm, dividing the temperature working range of the turbine blade, taking a temperature value in each temperature range as the initial value to solve, and finally comparing all the obtained results to obtain the minimum error function value and the corresponding temperature, namely the minimum error function value and the corresponding temperature are regarded as the real temperature of the surface of the turbine blade. The method can realize the radiation temperature inversion of the turbine blade with unknown emissivity in a radiation environment, does not need to predict the emissivity model of the blade while correcting the influence of environmental radiation, and can effectively reduce the measurement error.
Drawings
FIG. 1 is a schematic structural view of a turbine blade radiation thermometry apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic structural view of a turbine blade radiation thermometry apparatus according to a second embodiment of the present invention.
FIG. 3 is a schematic view of a measurement scheme of a turbine blade radiation thermometry apparatus provided according to an embodiment of the present invention.
FIG. 4 is a functional block diagram of a turbine blade radiation thermometry apparatus provided in accordance with an embodiment of the present invention.
FIG. 5 is a flow chart illustrating a method for radiation thermometry of turbine blades according to an embodiment of the present invention.
Wherein the reference numerals include: the device comprises turbine blades 1, a reflecting mirror 2, a collecting mirror 3, a collimating mirror 4, a first dichroic mirror 5, a first optical filter 6, a first focusing mirror 7, a first detector 8, a second dichroic mirror 9, a second optical filter 10, a second focusing mirror 11, a second detector 12, a third optical filter 13, a third focusing mirror 14, a third detector 15 and an optical fiber 16.
Detailed Description
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same blocks. In the case of the same reference numerals, their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention.
FIG. 1 illustrates a schematic structural view of a turbine blade radiation thermometry apparatus provided in accordance with a first embodiment of the present invention.
FIG. 2 shows a schematic structural diagram of a turbine blade radiation thermometry apparatus provided according to a second embodiment of the present invention.
As shown in fig. 1 and 2, a turbine blade radiation temperature measuring device according to a first embodiment of the present invention includes: the device comprises a light beam deflection device, two dichroic mirrors, a first detector device, a second detector device and a third detector device.
The radiation beam emitted by the turbine blade 1 is incident on a beam deflecting device.
The beam deflecting device includes: a reflector 2, a condenser 3 and a collimator 4.
The radiation beam is reflected by the reflector 2, and then the condenser 3 is converged on a primary image surface, a field stop with a proper size is arranged at the primary image surface, and the size of the field stop determines the size of the object space surface.
The mirror 2 performs the sweep operation in accordance with a control signal from the sweep controller, and radiation data of more points on the turbine blade 1 can be obtained along with the rotation of the turbine blade 1.
The radiation beam passes through the field diaphragm, is collimated by the collimating mirror 4 and then enters the first dichroic mirror 5, and the radiation beam is divided into a first light beam and a second light beam by the first dichroic mirror 5.
The first light beam is incident on a first detector device;
the first detector arrangement includes: a first filter 6, a first focusing mirror 7 and a first detector 8.
The first light beam is filtered by the first optical filter 6 and then focused on the target surface of the first detector 8 by the first focusing mirror 7.
The second light beam is incident on the second dichroic mirror 9, and is divided into a third light beam and a fourth light beam by the second dichroic mirror 9.
The third light beam is incident on the second detector device;
the second detector arrangement includes: a second filter 10, a second focusing mirror 11 and a second detector 12.
The third light beam is filtered by the second filter 10 and then focused on the target surface of the second detector 12 by the second focusing mirror 11.
The fourth light beam is incident on the third detector device;
the third detector arrangement includes: a third filter 13, a third focusing mirror 14 and a third detector 15.
The fourth light beam is filtered by a third filter 13 and then focused on the target surface of a third detector 15 by a third focusing lens 14.
The detector target surface converts the received radiation energy of the radiation beam into a corresponding voltage signal, and the voltage signal is filtered, decoupled, amplified and the like through the back end circuit, and finally collected through the high-speed collection card and stored to the PC end.
The turbine blade radiation temperature measuring device provided by the second embodiment of the invention is provided with an optical fiber 16 between the condenser lens 3 and the collimator lens 4 for transmitting the radiation beam at a long distance. The end face of the optical fiber 16 is arranged at the primary image surface, and the size of the core diameter determines the size of the object surface.
FIG. 3 is a schematic view of a measurement scheme of a turbine blade radiation thermometry apparatus provided according to an embodiment of the present invention.
FIG. 4 is a functional block diagram of a turbine blade radiation thermometry apparatus provided in accordance with an embodiment of the present invention.
As shown in fig. 3 and 4, the turbine blade radiation temperature measuring device provided by the embodiment of the invention has the following principle:
the swinging controller sends out a control signal to control the reflector to perform swinging so that the detector collects the environmental surface radiation and the target surface radiation on the turbine blade respectively. And meanwhile, the control signal is sent to the PC terminal, so that the PC terminal distinguishes the environmental surface signal from the target surface signal on the turbine blade.
The environmental surface radiation and the target surface radiation on the turbine blade enter a three-band radiation temperature measuring system in sequence, are subjected to color separation, filtering, photoelectric conversion and signal processing, and are finally collected and transmitted to a PC (personal computer) end through a collection card, the PC end calculates the environmental surface radiation and the target surface radiation on the turbine blade, and the temperature of a target position on the turbine blade is inverted by using a three-wavelength radiation temperature measuring method after the environmental reflection energy is corrected.
The method acquires the radiant energy of a plurality of target points with different temperatures on the turbine blade in three different wave bands and the reflected radiant data from the surrounding environment, adopts an error function specially constructed by a least square method, and solves the solution at the minimum value of the error function through a genetic algorithm to obtain the real temperature of all the target points.
The invention is based on the Planck blackbody radiation formula:
wherein the content of the first and second substances,
c 1 ＝3.7418×10 -16 Wm 2 is a first radiation constant;
c 2 ＝1.4388×10 -2 mK, first radiation constant;
λ is the object radiation wavelength;
t is the absolute temperature of the object.
For an actual object (not a black body), the radiation characteristic is multiplied by a factor epsilon based on the black body radiation formula, wherein the factor is defined as the emissivity of an object, and the emissivity of an object is defined as the ratio of the radiation capacity of the object to that of a black body at the same temperature:
wherein the content of the first and second substances,
M 1 is the radiant energy of an object at a temperature T;
M 2 is the radiant energy of a black body at a temperature T.
The turbine blade radiation energy collected by the three detectors provided by the invention mainly comprises two parts of the thermal radiation of the blade and the radiation of the peripheral blade reflected by the thermal radiation of the blade, wherein the reflected peripheral blade radiation energy is calculated according to the actual measurement result and the radiation angle factor of the corresponding structure (such as the blade and the inner wall of a combustion chamber) to the blade. Thus, for a selected three bands, the energy received by the detector can be expressed as:
S(λ l ，T i )＝ε b (λ l ，T i )S B (λ l ，T i )+[1-ε b (λ l ，T i )]S e (λ l ，T i )+S D (λ l ) (3)
wherein the content of the first and second substances,
S(λ l ，T i ) Is to measure the i-th position point at the wavelength lambda l The resulting detector radiation signal;
ε b (λ l ，T i ) Is the i-th position point at the wavelength λ l The emissivity of (d);
S B (λ l ，T i ) Is a black body with a pyrometer measuring the same temperature as the target blade at wavelength λ l The resulting level output signal;
S e (λ l ，T i ) The i-th position point of the receiving and target blade of the pyrometer is at the wavelength lambda l A level signal resulting from an infrared radiation of the premises in equal amounts to the ambient radiation;
S D (λ l ) Is the detector noise.
The emissivity is set to have a linear relationship with temperature between the temperature variation ranges of three target points on the turbine blade, namely:
ε b (λ l ，T i )＝ε b (λ l ，T 1 )[1+k l (T i -T 1 )] (4)
wherein k is l Is a parameter related to the slope in the linear equation;
k l ·ε b (λ l and T) is the slope of the equation of the straight line.
When the pyrometer captures three-band radiation at least three points on the turbine blade (three points are used as an example here), it can be derived from equation (3):
e 11 ＝ε b (λ 1 ，T 1 )S B (λ 1 ，T 1 )+[1-ε b (λ 1 ，T 1 )]S e (λ 1 ，T 1 )+S D (λ 1 ，T 1 )-S(λ 1 ，T 1 ) (5)
e 21 ＝ε b (λ 2 ，T 1 )S B (λ 2 ，T 1 )+[1-ε b (λ 2 ，T 1 )]S e (λ 2 ，T 1 )+S D (λ 2 ，T 1 )-S(λ 2 ，T 1 ) (6)
e 31 ＝ε b (λ 3 ，T 1 )S B (λ 3 ，T 1 )+[1-ε b (λ 3 ，T 1 )]S e (λ 3 ，T 1 )+S D (λ 3 ，T 1 )-S(λ 3 ，T 1 ) (7)
e 12 ＝ε b (λ 1 ，T 2 )S B (λ 1 ，T 2 )+[1-ε b (λ 1 ，T 2 )]S e (λ 1 ，T 2 )+S D (λ 1 ，T 2 )-S(λ 1 ，T 2 ) (8)
e 22 ＝ε b (λ 2 ，T 2 )S B (λ 2 ，T 2 )+[1-ε b (λ 2 ，T 2 )]S e (λ 2 ，T 2 )+S D (λ 2 ，T 2 )-S(λ 2 ，T 2 ) (9)
e 32 ＝ε b (λ 3 ，T 2 )S B (λ 3 ，T 2 )+[1-ε b (λ 3 ，T 2 )]S e (λ 3 ，T 2 )+S D (λ 3 ，T 2 )-S(λ 3 ，T 2 ) (10)
e 13 ＝ε b (λ 1 ，T 3 )S B (λ 1 ，T 3 )+[1-ε b (λ 1 ，T 3 )]S e (λ 1 ，T 3 )+S D (λ 1 ，T 3 )-S(λ 1 ，T 3 ) (11)
e 23 ＝ε b (λ 2 ，T 3 )S B (λ 2 ，T 3 )+[1-ε b (λ 2 ，T 3 )]S e (λ 2 ，T 3 )+S D (λ 2 ，T 3 )-S(λ 2 ，T 3 ) (12)
e 33 ＝ε b (λ 3 ，T 3 )S B (λ 3 ，T 3 )+[1-ε b (λ 3 ，T 3 )]S e (λ 3 ，T 3 )+S D (λ 3 ，T 3 )-S(λ 3 ，T 3 ) (13)
in the equation sets consisting of equations (5) to (13), equation (4) is substituted into each equation, and the values of the nine equation sets are all 0 (e) li =0,l =1,2,3,i =1,2,3), it can be seen that the equation set has nine unknowns (T) 1 ，T 2 ，T 3 ，k 1 ，k 2 ，k 3 ，ε b (λ 1 ，T 1 )，ε b (λ 2 ，T 1 )，ε b (λ 3 ，T 1 ) Other physical quantities may be measured or expressed as a function of the nine physical quantities. However, in actual measurement, due to the influence of factors such as noise, the solution satisfying all equations simultaneously is difficult to be solved by the equation set, but the least square solution of the equation set, namely the solution satisfying the formula (14), can be obtained by the solving algorithm of the nonlinear equation set such as the genetic algorithm, and the temperature and emissivity of all position points are inverted.
Operating temperature T of engine 1 Emissivity epsilon b And a parameter k l Can determine the value range in advance according to the empirical value byThe limitation of the search range improves the speed and accuracy of the solution. The temperature variation range is large, the working temperature range of the turbine blade is divided according to the step length by selecting the initial value, the working temperature range is respectively substituted into the genetic algorithm to be solved, a group of temperature solutions and temperature difference function value data can be obtained, finally, the error function values corresponding to the temperature solutions are compared to obtain the minimum error function value and the temperature corresponding to the minimum error function value, and the temperature is considered to be the real temperature of the surface of the turbine blade.
FIG. 5 is a flow chart illustrating a method for radiation thermometry of turbine blades according to an embodiment of the present invention.
As shown in FIG. 5, the method for measuring the radiation temperature of the turbine blade provided by the embodiment of the invention comprises the following steps:
a preprocessing step S0 of calibrating the three detector devices by adopting a high-temperature black body to obtain a relation S of black body temperature and three wavelength signals B (λ l ，T i ) (l =1,2,3; i =1,2,3) and detector noise S D (λ l )(l＝1，2，3)。
S1, establishing a radiation model, and calculating a radiation signal at any position point on the turbine blade through the radiation model.
S(λ l ，T i )＝ε b (λ l ，T i )S B (λ l ，T i )+[1-ε b (λ l ，T i )]S e (λ l， T i )+S D (λ l )
Wherein, the first and the second end of the pipe are connected with each other,
S(λ l ，T i ) Is the ith position point on the turbine blade at the wavelength lambda l Measuring the resulting detector radiation signal;
ε b (λ l ，T i ) Is the i-th position point at the wavelength λ l The emissivity of (d);
S B (λ l ，T i ) Is a black body with a pyrometer measuring the same temperature as the turbine blade at wavelength λ l The resulting level output signal;
S e (λ l ，T i ) Is the wavelength lambda between the pyrometer receiver and the turbine blade position point i l A level signal resulting from an infrared radiation of the premises in equal amounts to the ambient radiation;
S D (λ l ) Is the detector noise.
Wherein the emissivity epsilon b (λ l ，T i ) Set to be linear with temperature:
ε b (λ l ，T i )＝ε b (λ l ，T 1 )[1+k l (T i -T 1 )]
s2, collecting radiation on the surface of the turbine blade in operation to respectively obtain actual radiation S (lambda) on the surface of the turbine blade at three wavelengths l ，T i ) And the calculated ambient radiation S e (λ l ，T i ) And substituting the error function into an error function of a radiation temperature measurement method:
wherein l =1,2,3; i =1,2,3.
S3, setting a preset step length, dividing the actual working temperature range of the turbine blade to obtain a divided region endpoint temperature value T 1b 、T 2b 、T 3b … … is substituted as an initial value into the error function in step S3, and a genetic algorithm is used to solve the error function values corresponding to the initial values of different temperatures and the corresponding temperature values.
And S4, taking the temperature value corresponding to the minimum value obtained by calculating the error function as the real temperature of a plurality of target points on the measured turbine blade.
The radiation thermometry disclosed by the invention can measure the surface temperature of the turbine blade containing reflected radiation under the condition of unknown emissivity by only measuring and calculating actual radiation of a plurality of points of the turbine blade at three wavelengths and reflected radiation from the surrounding environment.
Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
The above embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.
Claims (6)
1. A turbine blade radiation temperature measurement method utilizes a turbine blade radiation temperature measurement device to realize temperature measurement, and the temperature measurement device comprises: the device comprises a light beam deflection device, two dichroic mirrors, a first detector device, a second detector device and a third detector device;
the radiation beam emitted by the turbine blade enters a beam deflection device, and the radiation beam enters a first dichroic mirror after passing through the beam deflection device and is divided into a first beam and a second beam;
the first light beam is incident into the first detector device to obtain a radiation signal under a first wavelength; the second light beam incident to the second dichroic mirror is divided into a third light beam and a fourth light beam; the third light beam is incident into the second detector device to obtain a radiation signal under a second wavelength; the fourth light beam is incident into the third detector device to obtain a radiation signal under a third wavelength;
distinguishing a turbine blade target surface radiation signal and an environment surface radiation signal in the three radiation signals, and inverting the temperature of a target position on the turbine blade after environment reflection energy correction;
the method is characterized by comprising the following steps:
s1, establishing a radiation model, and calculating a radiation signal at any position point on the turbine blade through the radiation model;
S(λ l ，T i )＝ε b (λ l ，T i )S B (λ l ，T i )+[1-ε b (λ l ，T i )]S e (λ l ，T i )+S D (λ l )
wherein the content of the first and second substances,
S(λ l ，T i ) Is the ith position point on the turbine blade at the wavelength lambda l Measuring the resulting radiation signal;
ε b (λ l ，T i ) Is the i-th position point at the wavelength λ l The emissivity of (d);
S B (λ l ，T i ) Is a black body at wavelength λ measuring the same temperature as the turbine blade by a pyrometer l A level output signal;
S e (λ l ，T i ) Is received by a pyrometer at a wavelength λ with the turbine blade at the ith location point l A level signal resulting from an infrared radiation of the premises in equal amounts to the ambient radiation;
S D (λ l ) Is detector noise;
s2, collecting the radiation signals of the surface of the turbine blade to respectively obtain the radiation S (lambda) of the target surface of the turbine blade at three wavelengths l ，T i ) And ambient surface radiation S e (λ l ，T i ) And respectively substituting the two into an error function of a radiation temperature measurement method:
wherein l =1,2,3; i =1,2,3;
s3, setting a preset step length, dividing the actual working temperature range of the turbine blade to obtain a divided region endpoint temperature value T 1b 、T 2b 、T 3b … as initial values are substituted into the error function in step S3, and a genetic algorithm is used to solve the error function values and corresponding temperature values corresponding to the different initial temperature values;
and S4, taking the temperature value corresponding to the error minimum value obtained by calculating the error function as the real temperature of the surface of the target point on the turbine blade.
2. The turbine blade radiation thermometry method of claim 1, wherein said beam steering means comprises: a reflector, a condenser and a collimator; the reflector is used for realizing a swinging action;
the radiation beam is reflected by the reflector and then converged to a primary image surface by the condenser, and a field diaphragm or an optical fiber is arranged at the primary image surface;
the radiation beam passes through the field diaphragm or the optical fiber and then is incident to the first dichroic mirror after being collimated by the collimating mirror.
3. The turbine blade radiation thermometry method of claim 2,
the size of the diameter of the field diaphragm determines the size of the object space surface;
the size of the optical fiber core diameter determines the size of the object side surface.
4. The turbine blade radiation thermometry method of claim 3,
the first detector arrangement includes: the device comprises a first optical filter, a first focusing lens and a first detector;
the first light beam is filtered by the first optical filter to obtain a light beam under a first wavelength, and the light beam is focused to a target surface of the first detector through the first focusing mirror;
the second detector arrangement comprises: the second optical filter, the second focusing mirror and the second detector;
the third light beam is filtered by the second optical filter to obtain a light beam under a second wavelength, and the light beam is focused to the target surface of the second detector through the second focusing mirror;
the third detector arrangement includes: a third optical filter, a third focusing mirror and a third detector;
and the fourth light beam is filtered by the third optical filter to obtain a light beam under a third wavelength, and is focused to the target surface of the third detector through the third focusing lens.
5. The turbine blade radiation thermometry method of claim 4, further comprising a preprocessing step S0 of calibrating the three detector devices with a high temperature black body to obtain a relation S of black body temperature and three wavelength signals B (λ l ，T i ) (l =1,2,3; i =1,2,3) and detector noise S D (λ l )(l＝1，2，3)。
6. The turbine blade radiation thermometry method of claim 5, wherein said emissivity e b (λ l ，T i ) Set to be linear with temperature:
ε b (λ l ，T i )＝ε b (λ l ，T 1 )[1+k l (T i -T 1 )]。
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