Single-point infrared temperature measuring device for aero-engine hot end component

Abstract

The utility model discloses a single-point infrared temperature measuring device for a hot end part of an aero-engine, and relates to the field of temperature in-situ detection of engine blades. The device mainly comprises an optical probe with a cooling function, a spectrograph, a photoelectric detector, a high-precision motion positioning platform and a data processing system. The front end of the optical probe reflects radiation energy on the surface of the blade into the collecting lens set through the reflector, the spectrograph divides spectral energy into three different wave bands, signals are collected through the photoelectric detector and the high-speed data collector, and temperature information is obtained through calibration and analysis. The high-precision motion positioning platform adopts a sliding table and a rotating mechanism, and can control the adjustment of the angle of a reflector and the stretching of an optical probe, thereby achieving the precise measurement of the temperatures of different target positions. The whole device is compact in structure, and has the characteristics of high measurement precision, flexible position, low energy loss and the like, and can resist high temperature of 1500 DEG C.

Description

Technical Field

[0001] The utility model relates to the field of aero-engine temperature measurement, and specifically to a single-point infrared temperature measurement device for hot-end components of an aero-engine. Background Technique

[0002] An aero-engine is a highly complex and precise thermal machinery, the heart of an aircraft, known as the "flower of industry", and also an important embodiment of a country's scientific and technological, industrial and national defense strength. In recent years, with the continuous iteration and update of aero-engines, they are developing towards high thrust-to-weight ratio and high turbine inlet temperature. At present, the turbine inlet temperature of the fourth-generation engine has exceeded 1700 °C. The turbine blades operate at high load for a long time at high temperature, which will lead to a reduction in blade life and even direct damage, threatening the operation safety of aero-engines. Therefore, monitoring the operating state of turbine blades can enable aero-engines to achieve high thrust-to-weight ratio and high fuel utilization rate, and can also provide important data for the research, development and manufacturing of aero-engines, promoting the further development of China's aero-engine cause.

[0003] The temperature measurement of hot-end components has always been a difficult problem in the engineering field. The temperature measurement and analysis of the surface of turbine blades can, on the one hand, ensure the service safety of the engine, and on the other hand, provide important data support for the material selection and structural manufacturing of the blades. However, considering the actual working condition limitations of the engine combustion chamber, including but not limited to harsh working environments such as high temperature and high pressure, strong magnetic field, high speed, and strong vibration, as well as the limited space inside the engine and complex positional relationships, most traditional temperature measurement methods are no longer applicable. Therefore, it is necessary to carry out research on special testing instruments and testing methods.

[0004] To solve this problem, patent (CN 113551779A) provides a prism six-channel system for measuring the temperature of aero-engine turbine blades. The designed six-channel prism system divides the optical path into three paths according to the wavelength band through a three-color dispersion prism, and then each path is spectrally divided through a dichroic mirror to form a six-channel optical system. The six wavelength bands can achieve the optimal selection of multiple wavelength bands according to the actual working conditions, so as to realize the on-line temperature measurement of the blade.

[0005] This technology still has some problems: 1) This method only explains the optical design of the six-channel spectroscopic optical path, and does not explain the specific structural design; 2) The six-channel design form of this method will lead to too large volume and weight of the whole system, which is not conducive to installation and testing; 3) This scheme is limited by the test position and test angle, and can only measure the temperature of a certain point on the blade, and cannot obtain the temperature distribution of the whole surface of the blade. Content of the Utility Model

[0006] Aiming at the deficiencies of existing detection devices, the utility model proposes a single-point infrared temperature measurement device for hot-end components of aero-engines, which mainly consists of a cooled optical probe, a spectrometer, a photodetector, a high-precision motion positioning platform and a data processing system. The front end of the optical probe reflects the radiant energy on the blade surface into the imaging lens group through a reflector, and the rear end is divided into three different wavelength channels by the spectrometer, and the temperature of the blade is calculated by the three-wavelength temperature measurement method. The device uses a sliding table plus a rotating mechanism to control the rotation of the reflector and the telescoping of the optical probe, so as to achieve accurate measurement of the temperature at different target positions. The whole device has a compact structure, and has the characteristics of withstanding high temperature of 1400 °C, high measurement accuracy, flexible position, and less energy loss.

[0007] The technical solution of the utility model is as follows:

[0008] A single-point infrared temperature measurement device for hot-end components of aero-engines, characterized in that it includes:

[0009] An optical probe, which includes a lens barrel and a reflector and a condenser lens group arranged in the lens barrel. Among them, a light window is provided at the front end of the lens barrel, and sapphire is installed at the light window, and the sapphire and the light window are fixed by laser welding; the center of the reflector is aligned with the center of the light window in the vertical direction, and the reflector is installed on an angle adjustment mechanism and controlled by an external first servo motor, and the angle of the reflector can be changed within the range of ±15°; a sandwich layer is provided inside the lens barrel as an air-cooling flow channel, an air-cooling inlet is provided in the middle of the lens barrel, and an air-cooling outlet is provided at the front-end light window of the lens barrel to cool the sapphire and blow the surface of the light window;

[0010] A spectrometer, connected to the rear end of the optical probe, for receiving the radiant energy of the blade transmitted by the condenser lens group and dividing it into three different bands;

[0011] A photodetector group, including a first detector, a second detector and a third detector, respectively receiving the spectral energy of the three bands separated by the spectrometer and converting it into a weak electrical signal;

[0012] A high-precision motion positioning platform, including a base and a moving slide rail installed on the base, a limiting device is provided on the moving slide rail, the optical probe is placed on the moving slide rail, and the telescoping of the optical probe is controlled by an external second servo motor, and the rotation of the reflector is controlled in cooperation with the first servo motor to realize the temperature measurement of different position targets;

[0013] A data processing system, connected to the spectrometer, for receiving the amplified electrical signal and obtaining the temperature information of the blade through calibration analysis and calculation.

[0014] Preferably, the sapphire has a high refractive index, extremely high hardness, and excellent heat and chemical resistance, and is used to isolate the internal and external environments of the optical window to protect the optical lens inside the probe.

[0015] Preferably, the sapphire has a thickness of 2 mm and a diameter of 5 mm.

[0016] Preferably, the mirror has a diameter of 4 mm and a thickness of 2.5 mm. The center of the mirror is aligned with the center of the optical window in the vertical direction, and the distance between them is 3.8 mm.

[0017] Preferably, the condenser lens group is composed of five standard spherical lenses, with an optical aperture of less than 10 mm, a total length of less than 335 mm, an object-side numerical aperture of 0.37, and a focal length of 89 mm. The condenser lens group is installed in the probe barrel through a positioning step, and the air gap between the lenses is ensured by a spacer ring.

[0018] Preferably, the barrel is made of a superalloy.

[0019] Preferably, after converting the received spectral energy into a weak electrical signal, the photodetector group amplifies it through an operational amplifier circuit, captures it by a high-speed data acquisition instrument, and finally processes and analyzes it by a data processing system.

[0020] Preferably, the front end of the barrel of the optical probe is buried into the engine interior through a 25-mm opening on the casing, and positioning and sealing are achieved through an airtight flange.

[0021] Compared with the prior art, the technical effects of the present utility model are as follows:

[0022] The present utility model provides a single-point infrared temperature measurement device for hot-end components of an aeroengine, which can be applicable to the temperature measurement of engine blades under harsh working conditions of high temperature, high pressure, and high speed.

[0023] Compared with the prior art, the advantages of the present utility model are:

[0024] 1) The optical probe is small in volume and light in weight, with a front-end aperture of less than 25 mm, facilitating installation and calibration;

[0025] 2) A servo motor is adopted to enable the probe to extend and retract and adjust the angle of the mirror, realizing temperature scanning measurement at multiple target positions.

[0026] 3) The precise configuration of the mirror and the condenser lens group can efficiently collect and focus the radiation energy from the hot-end components (such as blades) of the aeroengine, improving the accuracy and sensitivity of temperature measurement.

[0027] 4) The front end of the barrel of the optical probe is buried inside the engine through an opening on the casing, and positioning and sealing are achieved through an airtight flange, ensuring the stability and safety of the temperature measurement device during the operation of the engine.

[0028] 5) The barrel is made of superalloy and can withstand the high-temperature environment inside the aero-engine, ensuring the stability and durability of the temperature measurement device under harsh conditions. And the operating conditions are loose, because it is not only applicable to the temperature measurement of engine blades, but also applicable to the temperature detection of other target objects working in harsh environments such as high temperature, high pressure and strong magnetic field.

[0029] 6) A sandwich layer is provided inside the barrel as an air-cooling flow channel to cool the sapphire optical window through the air-cooling inlet and outlet, and purge the surface of the optical window, preventing the influence of thermal stress and pollution in the high-temperature environment on the temperature measurement accuracy. The sapphire optical window has high refractive index, high hardness, excellent heat resistance and chemical resistance, effectively isolating the internal and external environments of the optical window and protecting the optical lenses inside the probe. Description of the Drawings

[0030] Figure 1 is a schematic diagram of the single-point infrared temperature measurement device for the hot-end component of the aero-engine of the present utility model.

[0031] Figure 2 is a schematic diagram of the structure of the optical probe.

[0032] Figure 3 is an optical system diagram of the condenser lens group.

[0033] Figure 4 is a schematic diagram of the mirror angle adjustment mechanism.

[0034] Figure 5 is a schematic diagram of the structure of the high-precision motion positioning platform.

[0035] Wherein: 1 - high-precision motion positioning platform, 2 - data processing module, 3 - first detector, 4 - second detector, 5 - third detector, 6 - spectrometer, 7 - optical window, 8 - sapphire, 9 - cooling air inlet, 10 - casing, 11 - airtight flange, 12 - engine blade, 13 - condenser lens group, 14 - mirror, 15 - optical probe, 16 - air-cooling sandwich layer, 17 - angle adjustment structure, 18 - control line, 19 - first servo motor, 20 - base, 21 - second servo motor, 22 - moving slide rail, 23 - limiting device. Detailed Embodiment

[0036] In order to make the objectives, technical solutions and advantages of the present utility model more clearly understood, the present utility model will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model. The technical solutions in the embodiments of the present utility model will be clearly and completely described below in conjunction with the embodiments of the utility model and the drawings. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0037] Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present utility model. The experimental methods not specified in the following embodiments are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0038] Figure 1 It is a schematic diagram of a single-point infrared temperature measurement device for hot-end components of an aero-engine, mainly including an optical probe 15 with cooling, a spectrometer 6, a first photodetector 3, a second photodetector 4, a third photodetector 5, a high-precision motion positioning platform 1, and a data processing module 2.

[0039] The optical probe 15 mainly includes a sapphire 8, a mirror 14, a condenser lens group 13, and a superalloy barrel with a cooling air inlet 9. The front end of the optical probe 15 is provided with a light window 7 with a diameter of 5 mm, and the distance from the center point of the light window 7 to the front end of the probe is 10 mm; a sapphire 8 with a thickness of 2 mm and a diameter of 5 mm is installed at the light window 7. The sapphire has a high refractive index, extremely high hardness, excellent heat resistance and chemical resistance, so it can be used to isolate the internal and external environments of the light window and protect the optical lenses inside the probe. The sapphire 8 and the light window 7 are fixed by laser welding. A mirror 14 is installed inside the optical probe 15. The mirror material is brass, which can reflect the radiant energy on the blade surface into the optical probe. The diameter of the mirror 14 is 4 mm and the thickness is 2.5 mm. The center of the mirror is aligned with the center of the light window 7 in the vertical direction, and the distance between the two is 3.8 mm. The mirror 14 and the probe barrel are installed through a limit card slot; the front end of the optical probe 15 is buried inside the engine through an opening with a diameter of 25 mm on the casing 10, and positioning and sealing are achieved through an airtight flange 11.

[0040] Figure 2It is a schematic diagram of the optical probe structure. The probe barrel is made of superalloy. An air-cooled sandwich layer 16 is provided inside the barrel wall for the cold air flow to pass through. The flow channel diameter is about 1 mm. A cooling air inlet 9 is provided in the middle of the probe barrel. The cold air can be directly sent to the optical window 7 at the front end of the barrel through the air-cooled sandwich layer 16. Through this design, on the one hand, the condenser lens group is wrapped by cold air to ensure its normal and stable operation; on the other hand, it can play a purging role to avoid dust adhering to the surface of the sapphire 8 lens, ultimately affecting the acquisition of radiation signals.

[0041] Figure 3 It is an optical system diagram of the condenser lens group. The light reflected into the probe is transmitted to the spectrometer 6 through the condenser lens group 13 to realize the collection of the radiation energy of the blade. The condenser lens group 13 is composed of 5 lenses, all of which are standard spherical lenses. The optical aperture is less than 10 mm, the total length is less than 335 mm, the object space numerical aperture is 0.37, and the focal length is 89 mm. The condenser lens group 13 is installed in the probe barrel through the positioning step, and the air gap between the lenses is ensured by the spacer ring.

[0042] Figure 4 It is a schematic diagram of the mirror angle adjustment mechanism. The angle adjustment structure 17 on the back of the mirror is controlled by the first servo motor 19 outside through the control line 18, and the angle of the mirror can be changed within the range of ±15°, so as to realize the positioning scan of the local area of the engine blade.

[0043] The rear end of the optical probe is connected to the spectrometer 6. The spectrometer divides the spectral energy into three different bands, which are received by the first detector 3, the second detector 4 and the third detector 5 respectively. The band received by the first detector 3 is 1100±20 nm, the band received by the second detector 4 is 1200±20 nm, and the band received by the third detector 5 is 1300±20 nm. The detector converts the corresponding spectral energy into a weak electrical signal, and the operational amplifier circuit in it amplifies the weak electrical signal. The amplified electrical signal is collected by the data processing module 2, and finally the temperature information can be obtained through calibration and analysis.

[0044] Figure 5 It is a schematic diagram of the structure of the high-precision motion positioning platform. The high-precision motion positioning 1 platform adopts a slide table plus a rotating mechanism, mainly composed of a base 20, a second servo motor 21, a moving slide rail 22 and a limiting device 23. The movement of the entire platform can be realized by automatic control through programming. The second servo motor 21 drives the probe to slide up and down and rotate to realize the temperature measurement of different position targets.

[0045] The steps to calculate the temperature of the turbine blade by the present utility model are as follows:

[0046] 1) The rear end of the optical probe is placed on a high-precision motion positioning platform and is successively connected to the first detector, the second detector, the third detector and the data processing module. The position and angle of the optical probe are controlled by a servo motor to ensure that the optical window at the front end of the optical probe is aligned with the center of the blackbody furnace;

[0047] 2) The blackbody furnace is heated in the range of 600 - 1600 °C at intervals of 50 °C. After the temperature indication of the blackbody furnace is stable, the voltage data of the first detector, the second detector and the third detector are recorded to establish the optoelectronic response relationship of a single-point infrared temperature measurement device for the hot-end components of an aero-engine according to the present invention;

[0048] 3) The front end of the optical probe is buried into the engine through an opening with a diameter of 25 mm on the casing, and positioning and sealing are achieved through an airtight flange. The position and angle of the optical probe are controlled by a servo motor to ensure that the optical window at the front end of the optical probe is aligned with the center of the area to be measured on the blade;

[0049] 4) After the voltage data of the first detector, the second detector and the third detector are stable, they are recorded, and the temperature and emissivity of the blade are calculated through a multi-wavelength temperature measurement algorithm.

[0050] The principle of the multi-wavelength temperature measurement algorithm is as follows:

[0051] The radiation spectrum E of the blade is obtained by using the calibrated optoelectronic response relationship i :

[0052]

[0053] where: ε is the average emissivity of the flame in the detection band, T is the blade temperature, λ is the wavelength, k 2 is the second radiation constant, and k i is the optoelectronic response coefficient of a single-point infrared temperature measurement device for the hot-end components of an aero-engine according to the present invention. Take the logarithm of both sides of the above formula:

[0054]

[0055] Let ε' = lnε, Determine the least squares objective function f(ε')

[0056]

[0057] When f(ε') takes the minimum value, the corresponding ε and T are the required values.

Claims

1. A single-point infrared temperature measuring device for hot end components of an aircraft engine, characterized in that: include: An optical probe, comprising a lens barrel and a reflector and a condenser lens group arranged in the lens barrel, wherein a light window is arranged at the front end of the lens barrel, sapphire is installed at the light window, and the sapphire and the light window are fixed by laser welding; the center of the reflector is aligned with the center of the light window in the vertical direction, the reflector is installed on an angle adjustment mechanism, and the angle of the reflector can be changed within a range of ±15° through the control of an external first servo motor; an interlayer is arranged inside the lens barrel as an air cooling flow channel, an air cooling inlet is arranged in the middle of the lens barrel, and an air cooling outlet is arranged at the light window at the front end of the lens barrel to cool the sapphire and blow the surface of the light window; A spectrometer, connected to the rear end of the optical probe, for receiving the blade radiation energy transmitted by the condenser lens group and dividing it into three different bands; The photoelectric detector group includes a first detector, a second detector and a third detector, which respectively receive the spectral energy of the three bands separated by the spectrometer and convert them into weak electrical signals; The high-precision motion positioning platform comprises a base, a movable slide rail mounted on the base, a limit device is provided on the movable slide rail, the optical probe is placed on the movable slide rail, the extension and retraction of the optical probe is controlled by an external second servo motor, and the rotation of the reflector is controlled by the first servo motor to achieve temperature measurement of targets at different positions; The data processing system is connected to the spectrometer and is used to receive the amplified electrical signal and obtain the temperature information of the blade through calibration, analysis and calculation.

2. The single-point infrared temperature measuring device for hot end components of an aircraft engine according to claim 1, characterized in that: The sapphire has a high refractive index, extremely high hardness, and excellent heat resistance and chemical resistance. It is used to isolate the environment inside and outside the optical window and protect the optical lens inside the probe.

3. The single-point infrared temperature measuring device for hot end components of an aircraft engine according to claim 2, characterized in that: The sapphire has a thickness of 2 mm and a diameter of 5 mm.

4. The single-point infrared temperature measuring device for hot end components of an aircraft engine according to claim 1, characterized in that: The reflector has a diameter of 4 mm and a thickness of 2.5 mm. The center of the reflector is aligned with the center of the light window in the vertical direction, and the distance between the two is 3.8 mm.

5. The single-point infrared temperature measuring device for hot end components of an aircraft engine according to claim 1, characterized in that: The condenser group is composed of five standard spherical lenses, with an optical aperture of less than 10 mm, a total length of less than 335 mm, an object numerical aperture of 0.37, and a focal length of 89 mm. The condenser group is installed in the probe lens barrel through a positioning step, and the air gap is ensured between the lenses by spacers.

6. The single-point infrared temperature measuring device for hot end components of an aircraft engine according to claim 1, characterized in that: The lens barrel is made of high-temperature alloy.

7. The single-point infrared temperature measuring device for hot end components of an aircraft engine according to claim 1, characterized in that: The photoelectric detector group converts the received spectral energy into a weak electric signal, which is amplified by an operational amplifier circuit and captured by a high-speed data acquisition instrument, and finally processed and analyzed by a data processing system.

8. The single-point infrared temperature measuring device for hot end components of an aircraft engine according to any one of claims 1 to 7, characterized in that: The front end of the optical probe's lens barrel is buried inside the engine through a 25 mm opening on the casing, and is positioned and sealed by an airtight flange.

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