Staring type turbine blade high-temperature temperature field measuring system

Abstract

The invention discloses a staring type turbine blade high temperature field measurement system, and relates to the technical field of engine turbine blade radiation temperature measurement. The system solves the problems of insufficient high temperature tolerance, low measurement efficiency, vulnerable mechanical structure and the like in the prior art, the sapphire imaging lens group is used for receiving heat radiation on the surface of the turbine blade and imaging, the high-temperature-resistant ceramic probe is used for fixing and protecting the sapphire imaging lens group, and the optical filter is used for screening radiation light in a specific wave band; the radiation light processing device processes the radiation light and outputs temperature field distribution information, wherein the components are coaxially arranged. According to the system, a high-temperature-resistant aluminum oxide ceramic material and a sapphire lens are adopted, a scanning type mechanical structure is abandoned, non-contact real-time measurement of the turbine blade temperature field is achieved, the system can tolerate the 2000K high-temperature environment, and the system is mainly used for high-precision temperature field monitoring of aero-engine turbine blades.

Description

Technical Field

[0001] The present invention relates to the technical field of radiation temperature measurement of engine turbine blades. More specifically, the present invention relates to a staring type high-temperature temperature field measurement system for turbine blades. Background Art

[0002] As the power source of modern aircraft, the aero-engine directly determines the flight radius, flight speed and maneuverability of the aircraft. The temperature before the turbine in the engine is an important indicator to measure the thermal efficiency. Currently, for a new generation of aero-engines, the temperature before the turbine can even reach 2000K. The turbine blades work in an ultra-high temperature environment for a long time, and creep may occur, or even fracture, resulting in very serious consequences. Therefore, accurately measuring the temperature on the blade surface can timely understand the working state of the blade, avoid operating above the safe temperature, and ensure the safe and reliable operation of the turbine blades. It is an indispensable technical guarantee for the development of high-performance aero-engines.

[0003] In the temperature measurement of turbine blades, contact temperature measurement methods represented by thermocouples are difficult to perform on-line measurement on actual engines due to problems such as susceptibility to electromagnetic interference, low spatial resolution, easy damage, and the destruction of the structural strength and flow field of the surface to be measured. As a non-contact measurement technology, radiation temperature measurement has become the generally recognized optimal solution for turbine blade temperature measurement due to its high measurement accuracy, adjustable measurement distance, strong reliability, fast response speed, high temperature measurement upper limit, and high spatial resolution.

[0004] However, in previous studies, the application of the radiation temperature measurement method in turbine blade temperature measurement mainly focused on the measurement of the single-point temperature on the blade surface. The radiation pyrometers designed by researchers can only obtain local and limited temperature information on the blade surface, and cannot obtain the temperature distribution on the blade surface. Therefore, it is impossible to comprehensively and timely monitor and warn the turbine blades. Based on this, researchers proposed a scanning type temperature field measurement system, which adds a retractable and rotatable mechanical mechanism on the basis of a single-point radiation pyrometer, and obtains the temperature field information of the turbine blade through scanning measurement of each temperature point. However, this scanning type measurement system adds a complex mechanical structure, making it very easy to be damaged during the measurement process, greatly reducing the working life of the system. Moreover, the point-by-point scanning measurement takes a long time and cannot perform real-time rapid measurement. In addition, the alloy material used in the mechanical structure cannot withstand a high temperature of 2000K and cannot meet the high-temperature measurement requirements of the turbine blades of the new generation of engines. Summary of the Invention

[0005] The present invention provides a staring type turbine blade high-temperature temperature field measurement system, which solves the core problems in the prior art such as insufficient high-temperature tolerance, low measurement efficiency, and easy damage of mechanical structures. It can withstand ultra-high temperatures, measure the temperature field of the entire field of view in real time, and has a simple structure, a long service life, high measurement accuracy, and high reliability.

[0006] To achieve these and other advantages of the present invention, the present invention provides a staring type turbine blade high-temperature temperature field measurement system, including: A sapphire imaging lens group, which is used to receive the thermal radiation on the surface of the turbine blade and form an image; A high-temperature resistant ceramic probe, with the sapphire imaging lens group arranged inside its housing, for fixing and protecting the sapphire imaging lens group; A filter, which is arranged behind the high-temperature resistant ceramic probe, for filtering the radiation light; A radiation light processing device, which receives the radiation light screened by the filter and processes it, and outputs the temperature field distribution information of the turbine blade; Among them, the sapphire imaging lens group, the high-temperature resistant ceramic probe, the filter, and the radiation light processing device are arranged coaxially.

[0007] Preferably, the sapphire imaging lens group includes three lenses, which are, in order from the object side along the optical axis direction to the image side: a first meniscus negative lens, a second meniscus negative lens, and a biconvex positive lens; the convex surfaces of the first meniscus negative lens and the second meniscus negative lens both face the object side, that is, the direction of the turbine blade, and the concave surfaces face the image side. Among them, all three lenses are made of sapphire material.

[0008] Preferably, the radiation light processing device includes: An image sensor, which is used to receive the radiation light screened by the filter and perform photoelectric conversion and analog-to-digital conversion to generate a digital signal; An upper computer, which is connected to the image sensor, for processing the digital signal generated by the image sensor and outputting the temperature field distribution information of the surface to be measured of the turbine blade.

[0009] Preferably, the focal length F of the sapphire imaging lens group satisfies: 40mm < F < 50mm; the entrance pupil diameter ED of the sapphire imaging lens group satisfies: 10mm < ED < 20mm.

[0010] Preferably, the high-temperature resistant ceramic probe includes: An upper housing, with a blind hole provided on its connecting end face; A lower housing, with a cylindrical pin provided on its connecting end face that is adapted to the blind hole; The upper housing and the lower housing are cooperatively connected through the blind holes and the cylindrical pins, and are adhesively fixed using high-temperature ceramic glue; Among them, the three lenses of the sapphire imaging lens group are fixedly arranged between the upper housing and the lower housing.

[0011] Preferably, the interior enclosed by the upper housing and the lower housing of the high-temperature resistant ceramic probe is a circular cavity. The circular cavity has four different inner diameter values, which are the first inner diameter value, the second inner diameter value, the third inner diameter value, and the fourth inner diameter value in sequence from front to back. The first meniscus negative lens is arranged at the position of the first inner diameter value, the second meniscus negative lens is arranged at the position of the second inner diameter value, and the biconvex positive lens is arranged at the position of the third inner diameter value; the outer surfaces of the upper housing and the lower housing of the high-temperature resistant ceramic probe form two different outer diameter values, which are the first outer diameter value and the second outer diameter value in sequence from front to back. The position of the first inner diameter value corresponds to the position of the first outer diameter value, and the positions of the second inner diameter value, the third inner diameter value, and the fourth inner diameter value correspond to the position of the second outer diameter value to reduce the volume of the high-temperature resistant ceramic probe; Among them, both the upper housing and the lower housing of the high-temperature resistant ceramic probe are made of high-temperature resistant alumina ceramic material.

[0012] Preferably, the center wavelength range of the filter is 800nm - 900nm, and the half bandwidth range is 1nm - 10nm.

[0013] Preferably, the center wavelength range of the filter is 840nm - 860nm, and the half bandwidth range is 4nm - 6nm.

[0014] Preferably, the image sensor is a silicon-based image sensor, and the number of pixels is between 100w and 1000w.

[0015] Preferably, the four different inner diameter values of the high-temperature resistant ceramic probe are 37.6mm, 24.2mm, 20.2mm, and 16.4mm in sequence from front to back; the two different outer diameter values of the high-temperature resistant ceramic probe are 42mm and 30mm in sequence from front to back.

[0016] The present invention has at least the following beneficial effects: First, the present invention uses high-temperature resistant alumina ceramic materials to make probes, and sapphire materials to make imaging lens groups. Alumina ceramics have good high-temperature resistance and can work stably in the high-temperature environment inside the engine; the melting point of sapphire material is as high as 2313K, which can withstand the temperature of the turbine blades of the new generation of engines up to 2000K, ensuring the reliability of the high-temperature resistant ceramic probe in the high-temperature environment, so that the measurement system can accurately measure the temperature field of the turbine blades at high temperatures, and solve the problem that the existing measurement system cannot tolerate high temperatures. The sapphire imaging lens group can image the thermal radiation on the surface of the turbine blade through a combination of three lenses, namely two negative lenses and one positive lens. The image sensor receives and converts it into a digital signal, and the upper computer outputs the temperature field distribution information after processing, so that the temperature distribution of the surface of the turbine blade can be fully obtained, providing richer and more accurate data for the monitoring and early warning of the turbine blade, which helps to timely discover the abnormal temperature area of the turbine blade and ensure the safe operation of the turbine blade. Therefore, compared with the single-point radiation pyrometer, the sapphire imaging lens group of the present invention realizes high-precision imaging, directly obtains the temperature field distribution of the entire surface of the turbine blade, rather than the single-point temperature, so as to fully monitor the blade state.

[0017] Second, the present invention abandons the scanning mechanical structure and adopts gaze imaging, which does not require moving parts, avoids mechanical wear and failure, and significantly improves the life of the measurement system. The split design of the high-temperature resistant ceramic probe, that is, the upper shell + lower shell, is matched with the cylindrical pin through a blind hole and fixed with high-temperature ceramic glue, which not only ensures the assembly accuracy but also reduces the risk of thermal stress deformation. It not only reduces the complexity and failure rate of the measurement system, but also improves the stability of the measurement system.

[0018] Third, the present invention uses an image sensor to capture the radiation image of the entire turbine blade at one time, combined with real-time processing by the host computer, to achieve millisecond-level temperature field output, meeting the dynamic monitoring needs of aircraft engines. Therefore, the measurement system can respond quickly, monitor in real time, has a high upper temperature measurement limit and spatial resolution, can meet the needs of high-performance aircraft engine turbine blade temperature measurement, and effectively overcomes the defects of scanning measurement systems such as complex structure, easy damage, long measurement time, and short effective working time.

[0019] Fourthly, the focal length F of the sapphire lens group designed in the present invention meets the requirements of 40-50 mm, and the entrance pupil diameter meets the requirements of 10-20 mm. Through optimized design and matching with a narrow-band filter, the background noise can be effectively suppressed and the signal-to-noise ratio can be improved.

[0020] Fifth, the high-temperature resistant ceramic probe in the present invention uses four inner diameter values (37.6mm / 24.2mm / 20.2mm / 16.4mm) to accurately position the lens, and uses two outer diameter values (42mm / 30mm) to step-by-step reduce the volume, making the overall structure of the probe compact and easy to integrate into the narrow space of the engine.

[0021] Other advantages, objects and features of the present invention will be partly reflected by the following description, and partly will be understood by those skilled in the art through the research and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic side view structure diagram of the staring turbine blade high-temperature temperature field measurement system according to an embodiment of the present invention; Figure 2 It is a modulation transfer function diagram of the sapphire imaging lens group in an embodiment of the present invention; Figure 3 It is a Seidel diagram of the sapphire imaging lens group in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following further detailed description of the present invention is made in conjunction with the accompanying drawings, so that those skilled in the art can implement it according to the description in the specification.

[0024] It should be understood that terms such as "having", "including" and "comprising" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0025] It should be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified; in the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", "set" should be understood in a broad sense. For example, it can be fixedly connected, set, or detachably connected, set, or integrally connected, set. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. The orientation or positional relationship indicated by terms such as "transverse", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0026] Such as Figure 1As shown in the figure, an embodiment of the present invention provides a staring type high-temperature temperature field measurement system for turbine blades, including: a sapphire imaging lens group 1, which is used to receive the thermal radiation on the surface of the turbine blade and image it; a high-temperature resistant ceramic probe 2, inside whose housing the sapphire imaging lens group 1 is arranged, for fixing and protecting the sapphire imaging lens group 1; a filter 3, which is arranged behind the high-temperature resistant ceramic probe 2, for screening radiation light of a specific band; a radiation light processing device, which receives the radiation light screened by the filter 3 and processes it to output the temperature field distribution information of the turbine blade; wherein, the sapphire imaging lens group 1, the high-temperature resistant ceramic probe 2, the filter 3 and the radiation light processing device are arranged coaxially.

[0027] In the above embodiment, the sapphire imaging lens group 1 is composed of optical lenses made of high-temperature resistant sapphire material, which can focus the thermal radiation rays emitted from the surface of the turbine blade and form an image plane, so that the radiation intensity distribution of each point on the surface of the turbine blade and the light intensity distribution on the image plane form a one-to-one spatial correspondence relationship, thereby providing high-fidelity two-dimensional radiation information for temperature field measurement. The high-temperature resistant ceramic probe 2 is a protective housing made of high-temperature resistant ceramic, which can withstand a high temperature of 2000K. The sapphire imaging lens group 1 is fixed inside to prevent the high-temperature gas flow from directly impacting the surface of the sapphire imaging lens group 1. The sapphire imaging lens group 1, the high-temperature resistant ceramic probe 2, the filter 3 and the radiation light processing device are arranged coaxially, which can make the central axes of each optical element coincide, reduce aberration and improve the imaging quality.

[0028] The thermal radiation emitted by the turbine blade enters the high-temperature resistant ceramic probe 2. When the thermal radiation passes through the sapphire imaging lens group 1, it is focused and forms a thermal radiation image of the surface of the turbine blade. The imaged radiation light continues to propagate. After exiting the high-temperature resistant ceramic probe 2, the narrowband filter 3 screens out the infrared radiation light in the characteristic band of 800 - 900nm. The radiation light processing device can convert the radiation light signal into an electrical signal and generate a temperature field distribution map through data processing. In summary, this measurement system can work stably in a high-temperature environment of 2000K, realize non-contact real-time measurement of the temperature field of the turbine blade, avoid the vulnerable problem of the mechanical scanning structure, and improve the measurement efficiency and reliability.

[0029] In one specific embodiment, the sapphire imaging lens group 1 includes three lenses, which are, in order from the object side along the optical axis direction to the image side: the first meniscus negative lens 1-L1, the second meniscus negative lens 1-L2, and the biconvex positive lens 1-L3; wherein, the three lenses are all made of sapphire material.

[0030] Among them, the focal length F of the sapphire imaging lens group 1 satisfies: 40mm < F < 50mm; the entrance pupil diameter ED of the sapphire imaging lens group 1 satisfies: 10mm < ED < 20mm.

[0031] In the above-described embodiment, the first meniscus negative lens 1-L1, the second meniscus negative lens 1-L2, and the biconvex positive lens 1-L3 are all made of sapphire material, and the refractive index of each surface is 1.7682. The convex surfaces of the first meniscus negative lens 1-L1 and the second meniscus negative lens 1-L2 both face the object side, that is, the turbine blade direction, and the concave surfaces face the image side; both surfaces of the biconvex positive lens 1-L3 are convex surfaces, forming a biconvex structure. All three lenses are made of single-crystal sapphire α-Al2O3 material.

[0032] The melting point of the sapphire material is as high as 2313K, and it can still maintain the stability of the optical surface morphology in a working environment of 2000K, avoiding the softening and deformation problems of traditional optical glass. The meniscus negative lens structures of the first meniscus negative lens 1-L1 and the second meniscus negative lens 1-L2 can effectively compensate for spherical aberration and field curvature, and the biconvex positive lens structure of the biconvex positive lens 1-L3 provides the main optical power. The combination of the three lenses can control the total aberration of the measurement system within 0.01 mm. The transmittance of sapphire in the 800-900 nm band is >85%, and the total transmittance of the system can reach over 92% after being coated with an antireflection film. The three-lens design can reduce the surface curvature of a single lens compared with a single-lens design. For example, the center thickness of the first meniscus negative lens 1-L1 can reach 20 mm, improving the thermal shock resistance.

[0033] In the specific setting, the curvature radius of each surface in the sapphire imaging lens group 1 is 29mm, 17.8mm, 32.6mm, 20.1mm, 29.5mm and -72.3mm, respectively, and the thickness of each surface is 20mm, 101.1mm, 15mm, 4.4mm, 9.6mm and 50mm, respectively. Within the focal length range of 40-50mm, the measurement system can cover the typical object plane size of 45mm×40mm of the turbine blade, ensuring that the temperature field distribution of the entire blade surface can be captured by a single imaging, avoiding the time delay of scanning measurement. This focal length range can provide sufficient depth of field (about ±5mm) in a high temperature environment, compensate for the defocus caused by slight vibration or thermal deformation of the turbine blade, and improve the robustness of high temperature measurement. The focal length is optimized to match the curvature radius of the three-piece lens, so that the aberration coefficients such as spherical aberration and field curvature are <0.01mm, and the MTF value is still >0.38 at 144 lp / mm, meeting the sub-millimeter temperature resolution requirements. The entrance pupil diameter of 10-20mm ensures that sufficient infrared radiation energy passes through the lens group, and can still provide a radiation signal with a high signal-to-noise ratio at a high temperature of 2000K, overcoming the interference of high-temperature background noise. A smaller entrance pupil diameter (<20mm) can reduce the volume of the sapphire lens and reduce the risk of thermal stress cracking; at the same time, >10mm ensures the light flux, taking into account both high temperature resistance and measurement sensitivity. In summary, the parameter range of the focal length and entrance pupil diameter, through the multi-dimensional collaborative design of optics, mechanics and thermals, realizes high-resolution and high-reliability temperature field measurement in high-temperature environments, directly solving the key problems of the scanning system in the prior art, such as complex structure, high temperature resistance and slow measurement speed.

[0034] For further information, see Figure 2 , the Modulation Transfer Function (MTF) diagram of sapphire imaging lens group 1 is given. Modulation transfer function is one of the core indicators for evaluating the imaging quality of an optical system. It is used to quantify the ability of an optical system, such as a lens, to transmit different spatial frequencies (i.e., the degree of detail). The horizontal axis is the spatial frequency (unit: line pair / millimeter, lp / mm), which represents the logarithm of black and white stripes per millimeter. The higher the value, the finer the detail. The vertical axis is the modulation transfer function value, i.e., the MTF value (0~1), which represents the ratio of the modulation degree of the image and the object, and reflects the degree of contrast retention of the measurement system at this spatial frequency. Given by Figure 2 It can be seen that the modulation transfer function value of the sapphire imaging lens group 1 at high frequencies is greater than 0.6, and the modulation transfer function value at the cutoff spatial frequency of 144lp / mm is greater than 0.38, and is close to the diffraction limit, indicating that it can clearly distinguish the tiny temperature distribution differences on the surface of the turbine blades, which shows that the sapphire imaging lens group 1 has a very high imaging quality.

[0035] See also Figure 3, the Seidel diagram of the sapphire imaging lens group 1 is given. The Seidel coefficients are parameters for evaluating seven aberrations of an optical lens group, namely spherical aberration, coma, astigmatism, field curvature, distortion, axial chromatic aberration, and lateral chromatic aberration, and the Seidel diagram is a bar chart that intuitively shows the magnitudes of the Seidel coefficients in a visual form. Figure 3 The aberrations introduced by six surfaces in the sapphire imaging lens group 1 and the overall aberrations of the sapphire imaging lens group 1 are shown in Figure 3 . The grid lines are spaced 0.05 mm apart. Since the aberrations of positive and negative lenses cancel each other out, the total aberration of the sapphire imaging lens group 1 is very small, and all five aberration coefficients are less than 0.01.

[0036] In one specific embodiment, the radiation light processing device includes: An image sensor 4, which is used to receive the radiation light screened by the filter 3, perform photoelectric conversion and analog-to-digital conversion, and generate a digital signal; An upper computer 5, which is connected to the image sensor 4, is used to process the digital signal generated by the image sensor 4, and output the temperature field distribution information of the surface of the turbine blade to be measured.

[0037] Among them, the image sensor 4 is a silicon-based image sensor 4, and the number of pixels is between 1 million and 10 million.

[0038] In the above embodiment, the image sensor 4 can use silicon-based CMOS, the number of pixels is between 1 million and 10 million, the adjustable range of the exposure time is 1 µs - 10 s to adapt to different radiation intensities (1000K - 2000K) of the turbine blade, and the spectral response range covers 800 - 900 nm to match the central wavelength of the filter 3, which is 800 nm - 900 nm. The image sensor 4 first converts the optical signal into an analog electrical signal, and then converts the analog electrical signal into a digital signal through the built-in analog-to-digital converter. The upper computer 5 receives the digital signal transmitted by the image sensor 4, calculates the temperature based on the principle of radiation thermometry, and outputs the temperature field image.

[0039] In one specific embodiment, the high-temperature resistant ceramic probe 2 includes: An upper housing 210, on whose connecting end face there is a blind hole; A lower housing 220, on whose connecting end face there is a cylindrical pin 230 adapted to the blind hole; The upper housing 210 and the lower housing 220 are connected and fixed by the cooperation of the blind hole and the cylindrical pin 230, and are adhesively fixed with high-temperature ceramic glue; Among them, the three lenses of the sapphire imaging lens group 1 are fixedly arranged between the upper housing 210 and the lower housing 220.

[0040] In the above embodiments, precision blind holes are machined on the connection end face of the upper housing 210 with a diameter tolerance of ±0.02 mm for mating with the cylindrical pin 230 on the lower housing 220. Through the interference fit between the high-precision cylindrical pin and the blind hole, such as an interference amount of 0.01 - 0.03 mm, a non-loose positioning is achieved. Pre-alignment can be carried out first. By mating the cylindrical pin with the blind hole, the initial positioning of the upper and lower housings is ensured. Three lenses are loaded in sequence, and an optical alignment instrument is used to calibrate the optical axis, and then a high-temperature ceramic adhesive is used for adhesion and fixation. The split design allows the housing of the high-temperature ceramic probe 2 to expand freely after being heated.

[0041] In one specific embodiment, the interior surrounded by the upper housing 210 and the lower housing 220 of the high-temperature ceramic probe 2 is a circular cavity. The circular cavity has four different inner diameter values, which are the first inner diameter value, the second inner diameter value, the third inner diameter value, and the fourth inner diameter value in sequence from front to back. The first meniscus negative lens 1-L1 is arranged at the position of the first inner diameter value, the second meniscus negative lens 1-L2 is arranged at the position of the second inner diameter value, and the double-convex positive lens 1-L3 is arranged at the position of the third inner diameter value; the outer surfaces of the upper housing 210 and the lower housing 220 of the high-temperature ceramic probe 2 form two different outer diameter values, which are the first outer diameter value and the second outer diameter value in sequence from front to back. The position of the first inner diameter value corresponds to the position of the first outer diameter value, and the positions of the second inner diameter value, the third inner diameter value, and the fourth inner diameter value correspond to the position of the second outer diameter value to reduce the volume of the high-temperature ceramic probe 2. Among them, both the upper housing 210 and the lower housing 220 of the high-temperature ceramic probe 2 are made of high-temperature-resistant alumina ceramic materials.

[0042] Specifically, the four different inner diameter values of the high-temperature ceramic probe 2 are 37.6 mm, 24.2 mm, 20.2 mm, and 16.4 mm in sequence from front to back; the two different outer diameter values of the high-temperature ceramic probe 2 are 42 mm and 30 mm in sequence from front to back.

[0043] In the above embodiment, the interior enclosed by the upper housing 210 and the lower housing 220 is a circular cavity, and the circular cavity has four different inner diameter values, which are 37.6 mm, 24.2 mm, 20.2 mm, and 16.4 mm in sequence from front to back. The first meniscus negative lens 1-L1 is installed at the position of the first inner diameter value (37.6 mm), the second meniscus negative lens 1-L2 is installed at the position of the second inner diameter value (24.2 mm), the double convex positive lens 1-L3 is installed at the position of the third inner diameter value (20.2 mm), and the fourth inner diameter value (16.4 mm) reserves space for subsequent optical path adjustment. The three lenses of the sapphire imaging lens group 1 are fixed in the high-temperature resistant ceramic probe 2 by high-temperature ceramic glue, and the high-temperature ceramic glue can also be used as a stress buffer layer. Exemplarily, the high-temperature ceramic glue can be a zirconia-based ceramic adhesive, with a temperature resistance of ≥2000 K, a thermal expansion coefficient of 7.2×10 -6 / K, and a shear strength of ≥15 MPa (tested at 2000 K) after curing. After 100 thermal cycles, there is no peeling at the bonding interface, and the strength retention rate >90%. At the same time, the outer surfaces of the upper housing 210 and the lower housing 220 of the high-temperature resistant ceramic probe 2 form two different outer diameter values, which are 42 mm and 30 mm in sequence from front to back. The position of the first inner diameter value corresponds to the position of the first outer diameter value (42 mm), and the positions of the second inner diameter value, the third inner diameter value, and the fourth inner diameter value correspond to the position of the second outer diameter value (30 mm). This stepped design of the inner and outer diameters effectively reduces the volume of the high-temperature resistant ceramic probe 2 while ensuring the installation accuracy of the internal lenses and the integrity of the optical path.

[0044] The design of four different inner diameter values can provide precise installation positioning for the three lenses of the sapphire imaging lens group 1. Each lens can accurately be in the preset position, ensuring the accuracy of the optical path when light passes through the lens group, reducing aberration caused by lens installation deviation, and thus improving the imaging quality. At the same time, the upper and lower housings are fixed by the cooperation of high-precision cylindrical pins and blind holes and high-temperature ceramic glue adhesion, providing a stable support structure for the sapphire imaging lens group 1, enabling the high-temperature resistant ceramic probe 2 to still maintain the stable position of the sapphire imaging lens group 1 under harsh environments such as high temperature and vibration, and ensuring the reliability of the measurement system. The high-temperature resistant ceramic probe 2 adopts a stepped outer diameter design, which effectively reduces the overall volume of the probe while meeting the installation and optical path requirements of the internal optical elements. The smaller volume makes it easier for the high-temperature resistant ceramic probe 2 to be integrated into the narrow space inside the aeroengine, saving the space resources inside the engine and improving the space adaptability of the measurement system.

[0045] In addition, both the upper housing 210 and the lower housing 220 are made of high-temperature-resistant alumina ceramic material. The alumina ceramic material has excellent high-temperature resistance and can operate stably in a high-temperature environment of up to 2000K inside the engine, providing reliable protection for the internal sapphire imaging lens group 1, preventing the high-temperature gas flow from directly impacting the lens surface, and ensuring the normal operation of the measurement system in a high-temperature environment.

[0046] In one specific embodiment, the central wavelength range of the filter 3 is 800nm - 900nm, and the full width at half maximum (FWHM) range is 1nm - 10nm. Preferably, the central wavelength range of the filter 3 is 840nm - 860nm, and the FWHM range is 4nm - 6nm.

[0047] In the above embodiment, within the central wavelength range of the filter 3, the thermal radiation signal intensity of the turbine blade is high and stable. The filter 3 screens the radiation light in this wavelength band, which can ensure that the signal entering the radiation light processing device mainly comes from the effective thermal radiation of the turbine blade, reducing the interference of other non-target radiations, enabling the measurement system to more accurately capture the true temperature information of the turbine blade, and thus improving the accuracy of the temperature field measurement. The internal environment of the engine is complex, with background radiation noise generated by various interference sources. A relatively narrow FWHM, such as 1 - 10nm, preferably 4 - 6nm, can strictly limit the spectral range passing through the filter 3, greatly suppressing the background noise. It only allows the radiation light within an extremely narrow range near a specific wavelength to pass through, while blocking the background radiation light of other wavelengths. It should be noted that the thermal radiation of the turbine blade at 2000K is approximately blackbody radiation, and its radiation peak is located at 1.45μm (according to Planck's law), but the 800 - 900nm wavelength band still has a significant radiation intensity, accounting for 5% - 8%. By screening the radiation near 850nm with a narrowband filter, the background noise can be effectively suppressed, and high signal-to-noise ratio imaging can be achieved by utilizing the high quantum efficiency (>50%) of silicon-based CMOS. Exemplarily, the filter can be a hard-coated narrowband filter with a central wavelength of 850nm ± 5nm, an FWHM of 5nm, and a peak transmittance of ≥90%. In the non-passband range, 300 - 800nm and 900 - 2500nm, its cut-off depth is OD4, and the transmittance is ≤0.01%, and the transition band slope is ≤20nm.

[0048] A specific embodiment is given below.

[0049] The measurement object is a turbine blade, the object surface size is 45mm × 40mm, and the temperature measurement range is 1000K - 2000K.

[0050] 1. The specific configuration of the measurement system is as follows: Sapphire imaging lens group 1: It consists of three single-crystal sapphire (α - Al2O3) lenses, which are, in order from the object side to the image side: The first meniscus negative lens 1-L1: The convex surface curvature radius is 29 mm (object side), the concave surface curvature radius is 17.8 mm, and the central thickness is 20 mm.

[0051] The second meniscus negative lens 1-L2: The convex surface curvature radius is 32.6 mm (object side), the concave surface curvature radius is 20.1 mm, and the central thickness is 15 mm.

[0052] The biconvex positive lens 1-L3: The object side curvature radius is 29.5 mm, the image side curvature radius is -72.3 mm, and the central thickness is 9.6 mm.

[0053] Optical parameters: Focal length F = 45 mm, entrance pupil diameter ED = 15 mm, total transmittance > 92% (800 - 900 nm band), aberration < 0.01 mm.

[0054] High-temperature resistant ceramic probe 2: Shell material: Alumina ceramic (Al2O3), resistant to high temperature of 2000 K.

[0055] Split design: The upper shell 210 and the lower shell 220 are in interference fit (interference amount 0.02 mm) through a cylindrical pin (diameter 10 mm ± 0.02 mm) and a blind hole, and fixed with high-temperature ceramic glue.

[0056] Internal cavity: Stepped inner diameter design, successively 37.6 mm (for installing the first meniscus negative lens 1-L1), 24.2 mm (for installing the second meniscus negative lens 1-L2), 20.2 mm (for installing the biconvex positive lens 1-L3), 16.4 mm (optical path adjustment area); the outer diameter is divided into two sections: the front end is 42 mm (corresponding to the position of the first meniscus negative lens 1-L1), and the rear end is 30 mm.

[0057] Filter 3: Central wavelength 850 nm, half bandwidth 5 nm, peak transmittance > 90%.

[0058] Radiant light processing device: Image sensor 4: Silicon-based CMOS, 5 million pixels, spectral response range 800 - 900 nm, exposure time adjustable from 1 μs to 1 s.

[0059] Host computer 5: Based on the radiation temperature measurement algorithm, converts digital signals into temperature field distribution maps, with a spatial resolution of 0.1 mm and a temperature resolution of ±2 K (at 2000 K).

[0060] 2. The working process is as follows: The thermal radiation emitted from the surface of the turbine blade to be measured is captured by the high-temperature resistant ceramic probe 2, received by the sapphire imaging lens group 1 and transmitted backward. The radiation light emitted from the sapphire imaging lens group 1 first passes through the filter 3 for band screening and then is imaged on the image plane of the image sensor 4, and is converted into a digital signal through the photoelectric conversion and analog-to-digital conversion of the image sensor 4. Then it is transmitted to the host computer 5 for processing, and the temperature field distribution information of the surface of the turbine blade to be measured is output.

[0061] Through the collaborative design of the sapphire imaging lens group 1 and the high-temperature resistant ceramic probe 2 in this embodiment, the reliability problem of the traditional scanning system in a high-temperature environment is solved, and the full-field, high-precision real-time measurement of the temperature field of the turbine blade is realized.

[0062] The number of devices and the processing scale described here are used to simplify the description of the present invention. The applications, modifications, and variations of the present invention will be obvious to those skilled in the art.

[0063] Although the embodiments of the present invention have been disclosed as above, they are not limited to only the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily made. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the illustrated examples here.

Claims

1. A staring type turbine blade high temperature temperature field measurement system, characterized in that, Comprising: A sapphire imaging lens group, which is used to receive the thermal radiation on the surface of the turbine blade and image it; A high-temperature resistant ceramic probe, with the sapphire imaging lens group arranged inside its housing for fixing and protecting the sapphire imaging lens group; A filter, which is arranged behind the high-temperature resistant ceramic probe for filtering the radiation light; A radiation light processing device, which receives the radiation light screened by the filter and processes it to output the temperature field distribution information of the turbine blade; Wherein, the sapphire imaging lens group, the high-temperature resistant ceramic probe, the filter and the radiation light processing device are arranged coaxially.

2. The staring type turbine blade high-temperature temperature field measurement system according to claim 1, wherein, The sapphire imaging lens group includes three lenses, which are, in sequence from the object side along the optical axis direction to the image side: a first meniscus negative lens, a second meniscus negative lens and a biconvex positive lens; the convex surfaces of the first meniscus negative lens and the second meniscus negative lens both face the object side, that is, the direction of the turbine blade, and the concave surfaces face the image side. Among them, the three lenses are all made of sapphire material.

3. The staring type turbine blade high-temperature temperature field measurement system according to claim 1, characterized in that The radiation light processing device includes: An image sensor, which is used to receive the radiation light screened by the filter and perform photoelectric conversion and analog-to-digital conversion to generate a digital signal; An upper computer, which is connected to the image sensor for processing the digital signal generated by the image sensor and outputting the temperature field distribution information of the surface to be measured of the turbine blade.

4. The staring type turbine blade high temperature temperature field measurement system according to claim 2, wherein, The focal length F of the sapphire imaging lens group satisfies: 40mm < F < 50mm; the entrance pupil diameter ED of the sapphire imaging lens group satisfies: 10mm < ED < 20mm.

5. The staring type turbine blade high temperature temperature field measurement system according to claim 2, characterized in that, The high-temperature resistant ceramic probe includes: An upper housing, on whose connecting end face there is a blind hole; A lower housing, on whose connecting end face there is a cylindrical pin adapted to the blind hole; The upper housing and the lower housing are connected and fitted through the blind hole and the cylindrical pin, and are adhesively fixed using high-temperature ceramic glue; Wherein, the three lenses of the sapphire imaging lens group are fixedly arranged between the upper housing and the lower housing.

6. The staring type turbine blade high-temperature temperature field measurement system according to claim 5, characterized in that, The interior surrounded by the upper housing and the lower housing of the high-temperature resistant ceramic probe is a circular cavity, and the circular cavity has four different inner diameter values, which are, in sequence from front to back: a first inner diameter value, a second inner diameter value, a third inner diameter value and a fourth inner diameter value. The first meniscus negative lens is arranged at the position of the first inner diameter value, the second meniscus negative lens is arranged at the position of the second inner diameter value, and the biconvex positive lens is arranged at the position of the third inner diameter value; the outer surfaces of the upper housing and the lower housing of the high-temperature resistant ceramic probe form two different outer diameter values, which are, in sequence from front to back: a first outer diameter value, a second outer diameter value. The position of the first inner diameter value corresponds to the position of the first outer diameter value, and the positions of the second inner diameter value, the third inner diameter value and the fourth inner diameter value correspond to the position of the second outer diameter value to reduce the volume of the high-temperature resistant ceramic probe; Wherein, both the upper housing and the lower housing of the high-temperature resistant ceramic probe are made of high-temperature resistant alumina ceramic material.

7. The staring turbine blade high-temperature temperature field measurement system according to claim 1, wherein The central wavelength range of the filter is 800nm - 900nm, and the half bandwidth range is 1nm - 10nm.

8. The staring type turbine blade high temperature temperature field measurement system according to claim 7, characterized in that, The central wavelength range of the filter is 840 nm - 860 nm, and the half bandwidth range is 4 nm - 6 nm.

9. The staring type turbine blade high temperature temperature field measurement system according to claim 3, wherein The image sensor is a silicon-based image sensor, and the number of pixels is between 1 million and 10 million.

10. The gazing type turbine blade high temperature temperature field measurement system according to claim 6, characterized in that, The four different inner diameter values of the high-temperature resistant ceramic probe are 37.6 mm, 24.2 mm, 20.2 mm, and 16.4 mm in sequence from front to back; the two different outer diameter values of the high-temperature resistant ceramic probe are 42 mm and 30 mm in sequence from front to back.

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