System and method for synchronously measuring temperature and strain in high-temperature environment

Abstract

The invention relates to the technical field of aero-engine turbine blade cooling structure measurement, and discloses a temperature and strain synchronous measurement system and method.The system comprises a mainstream system, the mainstream system comprises an air inlet section, an experiment section and an exhaust section which are sequentially arranged from left to right, the experiment section is communicated with an experiment piece, and the experiment piece is communicated with the exhaust section; external air enters the air inlet section to be heated and then sequentially passes through the experiment piece and the exhaust section; the cold air system comprises an air storage tank, the air storage tank is communicated with the experiment piece through a pipeline, and the air storage tank is used for conveying cold air into the experiment piece; and the measuring part comprises a plurality of cameras, and the plurality of cameras are used for carrying out data acquisition on the temperature and the deformation strain of the experimental part. According to the invention, synchronous measurement of the temperature and the strain of the cooling structure under the high-temperature condition is realized, so that data support is provided for accurately evaluating damage and service life of turbine blades under real conditions.

Description

Technical Field

[0001] The invention relates to the technical field of measuring cooling structures of turbine blades of aircraft engines, and in particular to a system and method for synchronously measuring temperature and strain in a high-temperature environment. Background Art

[0002] In order to make aircraft engines have higher unit thrust and higher working efficiency, increasing the temperature before the engine turbine is an inevitable way to achieve these goals based on the Brayton cycle. However, such a high temperature before the turbine far exceeds the creep limit of the currently used high-temperature alloy materials at the working temperature, which seriously affects the service life of the turbine blades and reduces their working stability. In addition to the increasing turbine inlet temperature, the turbine blades are also subjected to mechanical loads caused by the high-speed rotation of the turbine, aerodynamic loads caused by the impact of the gas on the blades, chemical corrosion of the gas on the blades, thermal stress caused by uneven temperature distribution of the blades after heat exchange with the high-temperature gas, etc. Therefore, the turbine blades need to be cooled.

[0003] At present, the internal enhanced cooling structure of turbine blades is quite mature, which greatly improves the cooling efficiency of turbine blade structure. However, under the combined action of high-temperature combustion gas and cooling gas, the temperature distribution of turbine blades is extremely uneven, which causes a large difference in the thermal expansion between the various parts of the blades, resulting in a large deformation between the various parts of the turbine blades, thus generating a large thermal stress. The continuous improvement of cooling efficiency further increases the temperature gradient of the blades, causing greater thermal stress. This will cause creep, fatigue and other forms of damage to the turbine blades, directly affecting the safe and stable operation of the aircraft engine under the set working conditions.

[0004] Therefore, it is necessary to accurately measure the temperature and stress distribution of the turbine blades simultaneously, and to master the temperature field and stress field characteristics of the turbine blades, so as to evaluate the reliability and life of the turbine blades. Therefore, it is necessary to establish a temperature and strain synchronous measurement system and method in a high temperature environment to measure temperature and strain synchronously. Summary of the invention

[0005] The purpose of the present invention is to provide a system and method for synchronously measuring temperature and strain in a high temperature environment to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides a temperature and strain synchronous measurement system in a high temperature environment, comprising:

[0007] A mainstream system, wherein the mainstream system comprises an air intake section, a test section and an exhaust section arranged in sequence from left to right, wherein the test section is connected to a test piece, and the outside air enters the air intake section and is heated, and then passes through the test piece and the exhaust section in sequence;

[0008] A cold air system, comprising a gas storage tank, the gas storage tank being connected to the experimental piece through a pipeline, the gas storage tank being used to deliver cold air into the experimental piece;

[0009] The measuring piece includes a plurality of cameras, and the plurality of cameras are used to collect data on the temperature and deformation strain of the test piece.

[0010] Preferably, the experimental piece includes a tube body, which is installed at the experimental section, and observation windows and experimental windows are respectively opened on both sides of the tube body, an air film flat plate is installed in the experimental window, a cold air inlet pipe is fixedly connected to the tube body, the cold air inlet pipe is connected to the air storage tank, an impact plate is fixedly connected to one end of the cold air inlet pipe close to the air film flat plate, and a gap is set between the air film flat plate and the impact plate, and the camera collects data on the air film flat plate through the observation window.

[0011] Preferably, infrared glass and quartz optical glass are fixedly connected on both sides of the observation window, and the infrared glass is located on the side where the heated air enters. The cameras include infrared cameras and CCD cameras, and the infrared cameras and the CCD cameras correspond one-to-one to the infrared glass and the quartz optical glass, respectively.

[0012] Preferably, the end of the air intake section away from the experimental section is connected to a high-pressure centrifugal fan, and the air intake section is provided with an electric heater, an expansion section, a rectification stabilization section and a contraction section from left to right, and the left and right ends of the rectification stabilization section are respectively provided with a mainstream rectification gauze and a mainstream rectification grid.

[0013] Preferably, the gas storage tank is connected to an air compressor, a pressure-stabilizing valve, an electric flow control valve and a mass flow meter are arranged on the pipeline from left to right in sequence, and a cold air rectifying mesh is installed in the cold air inlet pipe.

[0014] Preferably, the outlet end of the exhaust section is connected to an exhaust tower, a cooling water nozzle and a booster water pump are provided on the exhaust section, and a cooling water flow component is provided on the booster water pump.

[0015] Preferably, the shooting direction of the infrared camera is inclined within 45° to the surface of the air film flat plate, and the shooting direction of the CCD camera is perpendicular to the surface of the air film flat plate.

[0016] Preferably, thermocouples are provided between the experimental section and the contraction section, and on the exhaust section and the cold air inlet pipe, and a pressure probe is installed on the experimental section.

[0017] A method for synchronously measuring temperature and strain in a high temperature environment comprises the following steps:

[0018] External air enters the air inlet section, is heated, and then is transported into the tube body;

[0019] The cold air is transported into the tube body by the provided gas storage tank;

[0020] The temperature and deformation strain of the air film plate are collected by an infrared camera through the infrared glass and by a CCD camera through the quartz optical glass, and the data are quantitatively analyzed and visualized.

[0021] Preferably, the air film flat plate is provided with a black primer and a plurality of white spots.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] 1. The present invention provides a temperature and strain synchronous measurement system in a high-temperature environment. The outside air enters the air intake section, is heated, and then transported to the test piece. The air storage tank transports cold air into the test piece, and the data of the test piece is collected through the set camera. It can realize the synchronous measurement of the temperature and strain of the cooling structure under high temperature conditions, thereby providing data support for accurately evaluating the damage and life of turbine blades under real conditions.

[0024] 2. The present invention provides a method for synchronously measuring temperature and strain in a high-temperature environment. The infrared camera is used to collect infrared technical data through the infrared glass, and the CCD camera is used to collect digital image technology data through the digital image correlation technology of quartz optical glass, so as to realize the data collection of temperature and deformation strain, and quantitatively analyze and visualize the data, thereby realizing a method combining infrared technology with digital image correlation technology, thereby providing data support for accurately evaluating the damage and life of turbine blades under real conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the experimental piece of the present invention;

[0028] Among them, 1. High-pressure centrifugal fan; 2. Air intake section; 201. Electric heater; 202. Expansion section; 203. Rectification and stabilization section; 204. Contraction section; 205. Mainstream rectification gauze; 206. Mainstream rectification grid; 3. Experimental section; 4. Exhaust section; 5. Gas storage tank; 6. Thermocouple; 7. Tube body; 8. Observation window; 9. Experimental window; 10. Air film plate; 11. Cold air intake pipe; 12. Impact plate; 13. Infrared glass; 14. Quartz optical glass; 15. Infrared camera; 16. CCD camera; 17. Air compressor; 18. Pressure regulating valve; 19. Electric flow control valve; 20. Mass flow meter; 21. Cold air rectification gauze; 22. Exhaust tower; 23. Cooling water nozzle; 24. Booster pump; 25. Cooling water flow parts; 26. Pressure probe; 27. Blue light; 28. Pitot tube; 29. ​​Electric heating control cabinet. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] Referring to the drawings, the present invention provides a temperature and strain synchronous measurement system in a high temperature environment, comprising:

[0032] Mainstream system: The mainstream system includes an air intake section 2, a test section 3 and an exhaust section 4 arranged from left to right. The test section 3 is connected to the test piece. The outside air enters the air intake section 2 and is heated, and then passes through the test piece and the exhaust section 4 in sequence.

[0033] A cooling system, comprising a gas storage tank 5, the gas storage tank 5 is connected to the experimental piece through a pipeline, and the gas storage tank 5 is used to transport cooling air into the experimental piece;

[0034] The measuring part includes a plurality of cameras, and the plurality of cameras are used for collecting data on the temperature and deformation strain of the test part.

[0035] To further optimize the solution, the experimental piece includes a tube body 7, which is installed at the experimental section 3, and has observation windows 8 and experimental windows 9 on both sides of the tube body 7. An air film flat plate 10 is installed in the experimental window 9. A cold air inlet pipe 11 is fixedly connected to the tube body 7, and the cold air inlet pipe 11 is connected to the air storage tank 5. An impact plate 12 is fixedly connected to one end of the cold air inlet pipe 11 close to the air film flat plate 10, and a gap is provided between the air film flat plate 10 and the impact plate 12. The camera collects data on the air film flat plate 10 through the observation window 8.

[0036] A further optimized solution is that an infrared glass 13 and a quartz optical glass 14 are fixedly connected to both sides of the observation window 8, the infrared glass 13 is located on the side where the heated air enters, and the plurality of cameras include an infrared camera 15 and a CCD camera 16, and the infrared camera 15 and the CCD camera 16 correspond to the infrared glass 13 and the quartz optical glass 14 one by one, respectively.

[0037] In one embodiment of the present invention, the infrared glass 13 is made of magnesium fluoride infrared glass, and the average transmittance of infrared waves after anti-reflection exceeds 90%. The quartz optical glass 14 is made of high temperature resistant quartz optical glass, and the visible light transmittance at high temperature exceeds 93%. The quartz optical glass 14 and the infrared glass 13 are respectively arranged in the middle area of ​​the air film flat plate 10, and the two optical glasses are supported by a support plate made of mica, fixed by another cover plate made of mica and screws, and a high temperature resistant sealing gasket of the same specification is placed under the mica support plate, and a better sealing effect can be achieved after the screws are tightened.

[0038] The three channels in the experimental section are all wrapped with a high-temperature resistant inorganic aluminum silicate insulation layer to reduce the heat dissipation on the high-temperature side of the mainstream. At the same time, in order to reduce the influence of heat conduction in the flow direction and span direction of the mainstream channel on the temperature distribution of the air film flat plate 10, a mica insulation pad with a low thermal conductivity coefficient is installed on the inner wall of the mainstream cavity. At the same time, the air film flat plate 10 is embedded in a support plate made of mica board and directly contacts the mica insulation pad. The impact cavity is also made of mica material.

[0039] To further optimize the solution, the end of the air intake section 2 away from the experimental section 3 is connected to the high-pressure centrifugal fan 1, and the air intake section 2 is provided with an electric heater 201, an expansion section 202, a rectification and stabilization section 203 and a contraction section 204 from left to right, and the left and right ends of the rectification and stabilization section 203 are provided with a mainstream rectification gauze 205 and a mainstream rectification grid 206 respectively.

[0040] To further optimize the solution, the air storage tank 5 is connected to an air compressor 17, a pressure-stabilizing valve 18, an electric flow control valve 19 and a mass flow meter 20 are arranged on the pipeline from left to right, and a cold air rectifying mesh 21 is installed in the cold air inlet pipe 11.

[0041] According to a further optimized solution, the outlet end of the exhaust section 4 is connected to an exhaust tower 22 , a cooling water nozzle 23 and a booster water pump 24 are provided on the exhaust section 4 , and a cooling water flow member 25 is provided on the booster water pump 24 .

[0042] According to a further optimization scheme, the shooting direction of the infrared camera 15 is inclined within 45° to the surface of the air film flat plate 10 , and the shooting direction of the CCD camera 16 is perpendicular to the surface of the air film flat plate 10 .

[0043] In one embodiment of the present invention, referring to Figure 1 , the CCD camera 16 is perpendicular to the surface of the air film flat plate 10. In order to allow the infrared camera 15 to capture more areas of the air film flat plate 10 and solve the problem of narrow shooting space, the infrared camera 15 is tilted to shoot at a fixed angle within 45° from the normal line of the air film flat plate. Both cameras are connected to the control computer via a data cable, and the shooting operation of the two cameras can be realized through the computer.

[0044] Specifically, a blue light lamp 27 is provided, which is located just above the observation window 8 and is used to illuminate the interior of the tube body 7 .

[0045] To further optimize the solution, thermocouples 6 are provided between the experimental section 3 and the contraction section 204 , on the exhaust section 4 and the cold air inlet pipe 11 , and a pressure probe 26 is installed on the experimental section 3 .

[0046] In one embodiment of the present invention, referring to Figure 1 Specifically, a Pitot tube 28 and an electric heating control cabinet 29 are also provided. The Pitot tube 28 is provided between the contraction section 204 and the experimental section 3 , and the electric heating control cabinet 29 is used to control the electric heater 201 .

[0047] A method for synchronously measuring temperature and strain in a high temperature environment comprises the following steps:

[0048] The outside air enters the air inlet section 2, is heated, and then transported to the tube body 7;

[0049] The cold air is delivered to the tube body 7 through the provided air storage tank 5;

[0050] The temperature and deformation strain of the air film plate 10 are collected by the infrared camera 15 through the infrared glass 13 and the CCD camera 16 through the quartz optical glass 14, and the data are quantitatively analyzed and visualized.

[0051] In one embodiment of the present invention, according to the focal length of the lens and the pixel requirements of the DIC analysis software, the distance and position of the CCD camera 16 from the shooting window are adjusted so that the shooting range is at the middle position in the span direction and the flow direction.

[0052] The mainstream gas is provided by a high-pressure centrifugal fan, and flows into the expansion section 202 after being heated by an electric heater 201, and then flows into the contraction section 204 after being rectified by the mainstream rectifier mesh 205 and the mainstream rectifier grid 206, and then flows into the experimental section 3. The cold air is provided by the high-pressure gas stored in the gas tank 5 in advance. While the experiment is being carried out, the air compressor 17 works normally to ensure the stability of the cold air flow. The cold air flows out of the gas tank 5, firstly stabilized by the self-operated pressure regulating valve 18, and then adjusted to the required flow value by the electric flow control valve 19. The electric flow control valve 19 and the mass flow meter 20 are connected by a control cabinet to achieve feedback regulation. After the cold air flows out through the air film hole, it is mixed with the mainstream and flows into the exhaust section 4 together. A cooling water nozzle 23 is designed in the exhaust section 4. According to the exhaust temperature requirements of the exhaust tower 22, the cooling water consumption of each working condition is calculated in advance. The cooled gas is finally discharged into the exhaust tower 22.

[0053] Since the infrared camera 15 is at an angle to the air film flat plate 10, the captured image cannot be directly used for quantitative analysis, and the tilted image needs to be corrected through post-processing operations. The post-processing correction operation is implemented through a self-written Matlab program. After the correction is completed, the data is imported into professional post-processing software for quantitative analysis and visualization. The experiment is realized by combining infrared technology with digital image related technology.

[0054] According to a further optimized solution, a black primer and a plurality of white spots are provided on the air film flat plate 10 .

[0055] In one embodiment of the present invention, a painting technology combining matte black primer and white speckle paint is used to achieve the painting requirement of simultaneous measurement of temperature and strain. The black primer and white speckle paint need to meet the following points when selecting: they can still maintain functionality at high temperatures; they have high ductility and can be well bonded to the air film plate under high strain and high temperature.

[0056] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do 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 should not be understood as a limitation on the present invention.

[0057] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A temperature and strain synchronous measurement system in a high temperature environment, characterized in that: include: A mainstream system, the mainstream system comprising an air intake section (2), an experimental section (3) and an exhaust section (4) arranged in sequence from left to right, the experimental section (3) being connected to an experimental piece, and outside air entering the air intake section (2) is heated and then passes through the experimental piece and the exhaust section (4) in sequence; A cold air system, comprising an air storage tank (5), wherein the air storage tank (5) is connected to the experimental piece through a pipeline, and the air storage tank (5) is used to transport cold air into the experimental piece; The measuring piece includes a plurality of cameras, and the plurality of cameras are used to collect data on the temperature and deformation strain of the test piece.

2. The temperature and strain synchronous measurement system in a high temperature environment according to claim 1, characterized in that: The experimental piece comprises a tube body (7), the tube body (7) is installed at the experimental section (3), observation windows (8) and experimental windows (9) are respectively provided on both sides of the tube body (7), an air film plate (10) is installed in the experimental window (9), a cold air intake pipe (11) is fixedly connected to the tube body (7), the cold air intake pipe (11) is connected to the air storage tank (5), an impact plate (12) is fixedly connected to one end of the cold air intake pipe (11) close to the air film plate (10), and a gap is provided between the air film plate (10) and the impact plate (12), and the camera collects data from the air film plate (10) through the observation window (8).

3. The temperature and strain synchronous measurement system in a high temperature environment according to claim 2, characterized in that: An infrared glass (13) and a quartz optical glass (14) are fixedly connected to both sides of the observation window (8), the infrared glass (13) is located on the side where the heated air enters, and the plurality of cameras include an infrared camera (15) and a CCD camera (16), the infrared camera (15) and the CCD camera (16) respectively correspond to the infrared glass (13) and the quartz optical glass (14).

4. The temperature and strain synchronous measurement system in a high temperature environment according to claim 3, characterized in that: The end of the air intake section (2) away from the experimental section (3) is connected to a high-pressure centrifugal fan (1), and the air intake section (2) is provided with an electric heater (201), an expansion section (202), a rectification and stabilization section (203) and a contraction section (204) from left to right in sequence, and the left and right ends of the rectification and stabilization section (203) are respectively provided with a mainstream rectification gauze (205) and a mainstream rectification grid (206).

5. The temperature and strain synchronous measurement system in a high temperature environment according to claim 2, characterized in that: The air storage tank (5) is connected to an air compressor (17), and a pressure stabilizing valve (18), an electric flow control valve (19) and a mass flow meter (20) are arranged on the pipeline from left to right in sequence, and a cold air rectifying gauze (21) is installed in the cold air intake pipe (11).

6. The temperature and strain synchronous measurement system in a high temperature environment according to claim 1, characterized in that: The outlet end of the exhaust section (4) is connected to an exhaust tower (22), the exhaust section (4) is provided with a cooling water nozzle (23) and a boosting water pump (24), and the boosting water pump (24) is provided with a cooling water flow member (25).

7. The temperature and strain synchronous measurement system in a high temperature environment according to claim 3, characterized in that: The shooting direction of the infrared camera (15) is inclined within 45° to the surface of the air film flat plate (10), and the shooting direction of the CCD camera (16) is perpendicular to the surface of the air film flat plate (10).

8. The temperature and strain synchronous measurement system in a high temperature environment according to claim 4, characterized in that: Thermocouples (6) are provided between the experimental section (3) and the contraction section (204), on the exhaust section (4) and on the cold air intake pipe (11), and a pressure probe (26) is installed on the experimental section (3).

9. A method for synchronously measuring temperature and strain in a high temperature environment, applicable to a system for synchronously measuring temperature and strain in a high temperature environment as claimed in claim 7, characterized in that: The following steps are involved: External air enters the air inlet section (2), is heated, and then is transported to the tube body (7); Cold air is transported into the pipe body (7) through the provided air storage tank (5); The temperature and deformation strain of the air film flat plate (10) are collected by using an infrared camera (15) through the infrared glass (13) and by using a CCD camera (16) through the quartz optical glass (14), and the data are quantitatively analyzed and visualized.

10. The method for synchronously measuring temperature and strain in a high temperature environment according to claim 9, characterized in that: The air film flat plate (10) is provided with a black primer and a plurality of white spots.

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