A device for measuring the surface infrared emissivity based on double blackbody alternating radiation

Abstract

The application relates to a surface infrared emissivity measuring device based on double-blackbody alternating radiation, which mainly comprises a first cavity blackbody, a second cavity blackbody, a chopper, a shell, a cooling pipeline, a cooler, an infrared thermal imager, an infrared spectral radiometer and a processor. The shell is used for mounting the first cavity blackbody, the second cavity blackbody and the chopper, the chopper is used for intermittently shielding the radiation of the radiation cavity mouth to the measured member, and the first cavity blackbody and the second cavity blackbody realize the alternating radiation to the measured member. A cooling passage is arranged in the blade and is used for cooling the blade. The application realizes the rapid switching of the blackbody temperature by rotating the blade of the chopper; two constant-temperature cavity blackbodies are adopted, the time required for temperature rising is saved, the emissivity measuring efficiency is improved, non-contact large-area measurement is realized, the surface infrared emissivity of the coating region of the aircraft to be measured can be obtained through one-time measurement process, and the coating damage condition can be intuitively recognized.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of infrared emissivity detection, and particularly relates to a surface infrared emissivity measuring device based on double-blackbody alternating radiation. BACKGROUND

[0002] An infrared low-emissivity coating, also known as an infrared stealth coating, is generally coated on the surface of a high-temperature object to reduce the infrared radiation energy of the object and achieve infrared stealth. In the process of use, the infrared low-emissivity coating is prone to damage such as aging, scratches, wear and tear, and peeling. Infrared emissivity is an important performance parameter for measuring the performance of an infrared low-emissivity coating. Damage to the coating causes changes in its infrared emissivity, which seriously affects its infrared stealth performance. By measuring the infrared emissivity of the coating, the damaged parts of the coating can be detected and the extent of the damage to the coating can be known, which is of great significance for guiding the repair and replacement of the coating.

[0003] Currently, the measurement method for the infrared emissivity of an infrared low-emissivity coating mainly uses a non-contact measurement method, and the specific measurement methods mainly include a double-band method and an environmental radiation method.

[0004] A Chinese patent application with the publication number CN103063312A discloses a measurement system and method for measuring the emissivity of an object. The principle of the patent is to obtain the infrared emissivity of the surface of the object by comprehensively considering the infrared radiation energy information of the surface of the object under two environments, and thus the method is called an environmental radiation method. The measurement device of the patent simulates environmental radiation by using a blackbody radiation source, changes the temperature of the blackbody, and thus changes the environmental radiation. The infrared radiation energy expressions of the surface of the object under two environments are combined, the influence of the unknown temperature of the surface of the object is eliminated, and thus the infrared emissivity of the surface of the object is obtained. Although the method can realize non-contact measurement, has high measurement accuracy, and can measure a large area, the blackbody of the measurement device of the patent needs to be continuously raised to the target temperature at a certain gradient when measuring the emissivity of the object. The traditional blackbody needs at least two to three minutes to be raised to the target temperature, and only one target sample can be sampled in one temperature rising cycle. If at least 10 sampling points are required according to the sampling method of the patent, it will take 30 minutes to sample only one area. Therefore, if the entire aircraft is sampled by using the measurement device of the patent, a large amount of time will be consumed, the measurement efficiency is too low, and the patent does not meet the actual field requirements. Moreover, the measurement device of the patent is used to measure the emissivity on the premise that the temperature of the test environment is unchanged, has high requirements for the equipment and the measurement environment, and is not suitable for actual field applications. SUMMARY

[0005] In order to overcome the problems of long sampling time period, low emissivity measurement efficiency, high requirements for equipment and measurement environment, and non-compliance with actual field applications, the present application provides a surface infrared emissivity measuring device based on double-blackbody alternating radiation.

[0006] The technical scheme adopted by the present application to solve its technical problems is:

[0007] A surface infrared emissivity measuring device based on double blackbody alternating radiation, mainly comprising a first cavity blackbody, a second cavity blackbody, a chopper, a shell, a cooling pipeline, a cooler, an infrared thermal imager, an infrared spectral radiometer, and a processor.

[0008] The measured component is located on the left side of the measuring device, the shell is a cylindrical hollow structure, the left end face and the right end face are closed, the left end face is provided with a mounting hole for mounting the first cavity blackbody, the second cavity blackbody, and the chopper.

[0009] The first cavity blackbody and the second cavity blackbody are symmetrically distributed with respect to the center line of the shell, are fixedly connected to the shell through the mounting hole of the shell, and the first cavity blackbody radiation cavity and the second cavity blackbody radiation cavity are flush with the left end face of the shell. The temperatures of the first cavity blackbody and the second cavity blackbody are different.

[0010] The chopper is installed on the mounting hole of the center line of the shell and is used for intermittently shielding the radiation of the radiation cavity to the measured component, so as to realize the alternating radiation of the first cavity blackbody and the second cavity blackbody to the measured component. The chopper comprises a motor, a connecting shaft, and a blade. The motor, the connecting shaft, and the blade are sequentially connected, the motor drives the blade to rotate through the connecting shaft. The connecting shaft is installed on the mounting hole of the center line of the shell, the motor is located in the shell and is fixedly connected to the shell, and the blade is located outside the shell. The blade is a circular ring with a notch, and a cooling passage is arranged in the blade. The cooling passage is communicated with a cooling pipe through a sealing bearing and is used for cooling the blade.

[0011] The shell and the chopper are connected to the cooler through the cooling pipe, respectively. The cooler is used for cooling the shell, the chopper, the first cavity blackbody, and the second cavity blackbody, so as to prevent additional radiation influence on the measured component.

[0012] The infrared thermal imager and the infrared spectral radiometer are respectively communicated with the processor and transmit signals.

[0013] The above-mentioned surface infrared emissivity measuring device based on double blackbody alternating radiation, the blade has a notch, the side boundary line of the notch is an Archimedean spiral, and the notch of the blade achieves the purpose of uniform exposure under the radiation conditions of the first cavity blackbody and the second cavity blackbody when the blade rotates.

[0014] The infrared thermal imager and the infrared spectral radiometer collect the infrared radiation temperature and brightness value of the measured member under the radiation condition of the first cavity black body and the second cavity black body in real time, and transmit the same to the processor.

[0015] The present application has the following advantages:

[0016] The present application has the following advantages: BRIEF DESCRIPTION OF DRAWINGS

[0017] The present application will be further described below in conjunction with the drawings and examples.

[0018] Figure 1 is a schematic diagram of the device of the present application;

[0019] Figure 2 is a front view of the chopper;

[0020] Figure 3 is a left view of the chopper;

[0021] Figure 4 is a right view of the chopper;

[0022] Figure 5 is a sectional view of the chopper;

[0023] Figure 6 is a cross-sectional view of the left end surface of the chopper blade;

[0024] Figure 7 is a cross-sectional view of the right end surface of the chopper blade;

[0025] Figure 8 is a left view of the shell;

[0026] Figure 9 is a sectional view of the shell.

[0027] In the drawings: 1. first cavity black body; 2. second cavity black body; 3. chopper; 4. shell; 5. cooling pipe; 6. cooler; 7. infrared thermal imager; 8. infrared spectral radiometer; 9. processor. DETAILED DESCRIPTION

[0028] Embodiment 1

[0029] A device for measuring surface infrared emissivity based on double blackbody alternating radiation, mainly composed of a first cavity blackbody 1, a second cavity blackbody 2, a chopper 3, a shell 4, a cooling pipe 5, a cooler 6, an infrared thermal imager 7, an infrared spectral radiometer 8, and a processor 9, as shown in Figure 1 .

[0030] The object of measuring surface infrared emissivity is the coating of an aircraft, which is used for measuring the surface infrared emissivity of the coating of an aircraft in the field.

[0031] The left end face of the shell 4 has three embedded holes for mounting the first and second cavity blackbodies 1 and 2 and the chopper 3. The left lower surface and the right upper surface of the shell 4 have through holes connected to the cooling pipe 5. The first and second cavity blackbodies 1 and 2 are installed into the shell 4 from the left end face, and the radiation cavities of the first and second cavity blackbodies 1 and 2 are exposed to the left end face. The connecting shaft of the chopper 3 is installed in the hole at the center of the shell 4, and the right end face of the chopper 3 blade is attached to the left end face of the shell. The left end face of the chopper 3 blade has a through hole connected to the cooling pipe 5 for cooling water, and the infrared thermal imager 7, the infrared spectral radiometer 8, and the processor 9 are connected. The first and second cavity blackbodies 1 and 2 are respectively installed in the holes with the same depth and distance from the center of the left end face of the shell 4 by threads, ensuring that the cavities of the first and second cavity blackbodies 1 and 2 are flush with the left end face of the shell 4. The right end face of the connecting shaft of the chopper 3 is connected to the motor fixed to the shell 4 by a key, and the blade is driven by the motor to rotate tightly against the cavities of the first and second cavity blackbodies 1 and 2, so that the cavities of the first and second cavity blackbodies 1 and 2 are alternately exposed, realizing the rapid alternating radiation of the two cavity blackbodies to the measured aircraft coating area. The through holes in the left lower surface and the right lower surface of the shell 4 are connected to the cooler 6 through sealed bearings and the cooling pipe 5 to realize rapid cooling of the device. The infrared thermal imager 7 and the infrared spectral radiometer 8 are connected to the processor 9.

[0032] As shown in Figure 1 .

[0033] The first part is the chopper 3 composed of a motor, a connecting shaft, and a blade. The blade has an Archimedes spiral shape, which can make the exposure of blackbody radiation more uniform, and the blade contains two hollow cooling channels, one near the left end face of the blade and the other near the right end face of the blade, as shown in Figure 6 , 7The through hole in the center of the left end surface of the blade is connected to the cooling pipe through a sealing bearing for the input of cooling water, and is connected to the connecting shaft through the hollow cooling passage. The hollow cooling passage in the connecting shaft is connected to the passage in the blade, and is connected to the hollow shell through the two-directional through holes in the right end of the connecting shaft, so that the cooling water is injected from the left end surface of the blade and injected into the shell through the two-directional holes in the right end of the connecting shaft. The right end surface of the connecting shaft has a T-shaped key groove for key connection with the rotating shaft of the motor, so that the two are relatively fixed. After the motor is fixed to the right end inner wall of the hole in the center of the shell 4, the motor rotates relative to the shell 4 by driving the connecting shaft, so that the blade rotates at a variable speed, so that the first and second cavity blackbodies 1 and 2 alternately radiate more quickly and uniformly, as shown in Figure 5

[0034] The second part is composed of the first and second cavity blackbodies 1 and 2 with a length-to-radius ratio of 10 in the inner cavity, and can set different radiation temperatures. They are installed in the shell 4 and cooled by the cooler 6.

[0035] The third part is the shell 4, which is a hollow cylinder. The through holes in the left lower surface and the right lower surface are connected to the inlet and outlet of the cooling pipe 5, respectively. The holes distributed on both sides of the left end surface have threads for installing the first and second cavity blackbodies 1 and 2. The hole in the center of the left end surface of the shell 4 is used to install the connecting shaft of the chopper 4. A semicircular groove is opened at the position corresponding to the two-directional hole of the connecting shaft, as shown in Figure 9 The semicircular groove allows the cooling water in the two-directional hole to be injected alternately into the shell 4. The rapid flow of the cooling water prevents the cavity mouth of the first or second cavity blackbody 1 or 2 from causing additional radiation effects on the target when it is covered by the blade of the chopper 4. The right end surface of the shell 4 is connected to the shell by threads, which can be disassembled for the installation of the cavity blackbody and the motor inside the shell.

[0036] The fourth part is the cooling pipe 5 and the cooler 6, which supply rapidly flowing cooling water to cool the first and second cylindrical cavity blackbodies 1 and 2, the chopper 3, and the shell 4, preventing the device from causing additional radiation effects on the coating area of the aircraft under test.

[0037] The fifth part is composed of an infrared thermal imager 7, an infrared spectral radiometer 8, and a processor 9. The infrared thermal imager 7 and the infrared spectral radiometer 8 collect the infrared radiation temperature and brightness values of the coating area of the aircraft under test under the radiation conditions of the first and second cavity blackbodies in real time, and transmit them to the data processor 9. The average environmental infrared radiation brightness under the radiation conditions of the first and second cavity blackbodies and the average infrared radiation brightness of each pixel point of the coating area of the aircraft under test under the radiation conditions of the first and second cavity blackbodies are calculated, respectively. Finally, the infrared emissivity of the coating area of the aircraft under test in the waveband is calculated, and the corresponding image is output.​

Claims

1. A device for measuring the surface infrared emissivity based on double blackbody alternating radiation, characterized in that, It mainly comprises a first cavity blackbody (1), a second cavity blackbody (2), a chopper (3), a shell (4), a cooling pipe (5), a cooler (6), an infrared thermal imager (7), an infrared spectral radiometer (8) and a processor (9). The measured component is located on the left side of the measuring device, the shell (4) is a cylindrical hollow structure, the left and right end faces are closed, the left end face is provided with a mounting hole for mounting the first cavity blackbody (1), the second cavity blackbody (2) and the chopper (3); The first cavity blackbody (1) and the second cavity blackbody (2) are symmetrically distributed with respect to the center line of the shell (4), are fixedly connected to the shell (4) through the mounting hole of the shell (4), and the radiation cavity of the first cavity blackbody (1) and the radiation cavity of the second cavity blackbody (2) are flush with the left end face of the shell (4); the first cavity blackbody (1) and the second cavity blackbody (2) have different temperatures; The chopper (3) is installed on the mounting hole of the center line of the shell (4) and is used for intermittently shielding the radiation cavity from radiating to the measured component, so as to realize the alternate radiation of the first cavity blackbody (1) and the second cavity blackbody (2) to the measured component; The chopper (3) comprises a motor, a connecting shaft and a blade; the motor, the connecting shaft and the blade are sequentially connected, the motor drives the blade to rotate through the connecting shaft; the connecting shaft is installed on the mounting hole of the center line of the shell (4), the motor is located in the shell (4) and is fixedly connected to the shell (4), and the blade is located outside the shell (4); the blade is a circular ring with a notch, an internal cooling passage is arranged in the blade, the cooling passage is communicated with the cooling pipe (5) through a sealing bearing and is used for cooling the blade; The hollow cooling passage in the connecting shaft is connected with the passage in the blade and is connected with the hollow shell through two flow-directional through holes in the right end of the connecting shaft, so that the cooling water is injected from the left end face of the blade and is injected into the shell through the two-directional holes in the right end of the connecting shaft; The shell (4) and the chopper (3) are connected with the cooler (6) through the cooling pipe (5), and the cooler (6) is used for cooling the shell (4), the chopper (3), the first cavity blackbody (1) and the second cavity blackbody (2) to prevent the additional radiation influence on the measured component; The infrared thermal imager (7) and the infrared spectral radiometer (8) are communicated with the processor (9) and transmit signals. The blade has a notch, the side boundary line of the notch is an Archimedes spiral line, and the notch of the blade realizes the purpose of uniform exposure under the radiation conditions of the first cavity blackbody (1) and the second cavity blackbody (2) when the blade rotates.

2. The apparatus for measuring the surface infrared emissivity based on the double blackbody alternating radiation according to claim 1, wherein, The infrared thermal imager (7) and the infrared spectral radiometer (8) collect the infrared radiation temperature and brightness value of the measured component under the radiation conditions of the first cavity blackbody (1) and the second cavity blackbody (2) in real time and transmit them to the processor (9).

Images