Method and device for measuring the surface infrared emissivity of an aeronautical component based on a uniform temperature field

Abstract

The present application relates to a kind of based on uniform temperature field's aviation component surface infrared emissivity measuring device, including infrared detector, platform, thermostat, processor, data line, reference plate.Reference plate, the aviation component to be measured is located in thermostat.The present application also relates to a kind of based on uniform temperature field's aviation component surface infrared emissivity measuring method, including setting reference plate, installation aviation component to be measured, establish the view plane coordinate system of infrared detector, collect the infrared radiation luminance value of each pixel point corresponding area, solve the average infrared radiation luminance of reference plate, solve the average infrared radiation luminance of aviation component to be measured under constant temperature condition, solve the infrared emissivity of aviation component to be measured, draw the process of the surface infrared emissivity graph of aviation component to be measured.The present application can generate surface infrared emissivity graph of target surface once measurement, realizes the emissivity measurement of curved surface target, improves the measurement precision of target surface infrared emissivity.

Description

Technical Field

[0001] This invention belongs to the field of infrared emissivity detection technology, specifically relating to a method and device for measuring the infrared emissivity of an aerospace component surface based on a uniform temperature field. Background Technology

[0002] Infrared emissivity, the ratio of the self-radiated energy of a real object to that of an ideal blackbody, is an important physical property parameter of materials and one of the indicators used to study radiative heat transfer and measure material quality. Measuring the infrared emissivity of an object is a crucial aspect of infrared radiation analysis. Infrared emissivity can be divided into directional emissivity and hemispherical emissivity based on the direction of radiation. For a Lambertian surface, the normal emissivity is numerically equal to the hemispherical emissivity. Theoretically, emissivity measurement is relatively simple; obtaining the target radiation at a known temperature yields the emissivity of the surface being measured. However, actual targets are always under specific environmental conditions, and infrared radiation from these conditions inevitably strikes the surface being measured. Furthermore, since the surface being measured is not a blackbody, it will inevitably reflect environmental radiation, affecting the measurement of its emissivity.

[0003] Chinese invention patent CN114235690A discloses a method and apparatus for measuring the surface emissivity of aircraft coatings. This method and apparatus can achieve non-contact, large-area measurement of the surface emissivity of aircraft coatings. However, because the apparatus uses a blackbody radiation source to irradiate the target twice, the different temperatures of the two irradiations cause a change in the target's temperature, resulting in low measurement accuracy. Furthermore, because the apparatus relies on a blackbody radiation source to provide uniform parallel radiation to the target, it cannot measure the emissivity of curved surfaces. Summary of the Invention

[0004] To overcome the problems of low measurement accuracy and inability to measure the emissivity of curved targets in surface infrared emissivity measurement, this invention proposes a method and device for measuring the surface infrared emissivity of aerospace components based on a uniform temperature field.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] An infrared emissivity measurement device for aerospace components based on a uniform temperature field mainly includes an infrared detector, a platform, a constant temperature chamber, a processor, a data cable, and a reference board.

[0007] The processor is connected to the infrared detector and the constant temperature chamber via the data line and transmits signals; the infrared detector is located on the platform and is used to collect the infrared radiation brightness of the aircraft component under test; the reference plate and the aircraft component under test are located inside the constant temperature chamber.

[0008] The temperature control chamber has a temperature range of 30–300°C and maintains a constant temperature. The transparent door of the temperature control chamber faces the infrared detector, which can collect the infrared radiation brightness of the aircraft component under test and the reference plate inside the temperature control chamber through the transparent door.

[0009] The reference plate has an infrared radiation coating on one side and includes a first reference plate and a second reference plate. The first reference plate and the second reference plate are placed one above the other and located on one side of the aerospace component to be tested.

[0010] The surfaces of the first and second reference plates with infrared radiation coatings are the front surfaces, which face the direction of the infrared detector. The normals at the center points of the front surfaces of the first and second reference plates both pass through the midpoint of the lens of the infrared detector.

[0011] The distance from the center point of the front of the first reference plate and the second reference plate to the center point of the infrared detector lens is equal, both being L2, where L2 = 1500~2500mm.

[0012] The aforementioned surface infrared emissivity measuring device has an infrared detector with a measurement band of Δλ, where Δλ is in the range of 3 to 5 μm, a frame pixel of 640×512, a frame rate of 25 Hz, an integration time of 4490 μs, and an output mode of infrared radiance.

[0013] In the aforementioned surface infrared emissivity measuring device, both the first reference plate and the second reference plate are square plates with equal side lengths, both being L1, where L1 = 25–40 mm.

[0014] Within the wavelength range of 3–5 μm, the infrared emissivity of the front side of the first reference plate is ε. c1 , ε c1 =0.395~0.465, the infrared emissivity of the front side of the second reference plate is ε c2 , ε c2 =0.505~0.585.

[0015] A method for measuring the surface infrared emissivity of aerospace components based on a uniform temperature field includes the following steps:

[0016] Step 1, Set up the reference board

[0017] Place the first reference plate and the second reference plate in a constant temperature chamber, and adjust them so that the normals at the center points of the front faces of both the first and second reference plates pass through the midpoint of the infrared detector lens. The distances from the center points of the front faces of the first and second reference plates to the midpoint of the infrared detector lens are equal, both being L2, where L2 = 1500–2500 mm.

[0018] Step 2, Install the aircraft component to be tested

[0019] The aircraft component to be tested is installed in the constant temperature chamber, with the infrared radiation direction of the aircraft component being the test direction, so that the test direction of the aircraft component is facing the infrared detector lens, and the minimum distance between the aircraft component to be tested and the midpoint of the infrared detector lens is equal to L2.

[0020] Step 3: Establish the view plane coordinate system of the infrared detector.

[0021] The aircraft component to be tested and the reference plate are projected onto the viewing plane of the infrared detector. A Cartesian coordinate system is established with the lower left pixel of the infrared detector as the origin. The viewing plane of the infrared detector is then divided into grids so that each pixel of the infrared detector is located on a grid node.

[0022] Step 4: Collect the infrared radiation brightness value A of the corresponding area of ​​each pixel under constant temperature conditions. (x，y)

[0023] Turn on the surface infrared emissivity measuring device and adjust the temperature of the constant temperature chamber to T. c T c =230~300℃, so that the temperature of the first reference plate, the second reference plate, and the aircraft component under test are all T. c .

[0024] Adjust the infrared detector so that the first reference plate 7, the second reference plate 8, and the aircraft component under test are all within the field of view of the infrared detector. The front area of ​​the first reference plate is S1, the front area of ​​the second reference plate is S2, and the area of ​​the aircraft component under test is S3.

[0025] The infrared detector enters a stable operating state, and within the measurement band Δλ range, Δλ = 3~5μm, it simultaneously acquires the infrared radiance A at each pixel point of the first reference film 7, the second reference film 8, and the aerospace component under test within the field of view. (x，y) The data collection time is t1, where t1 = 6 to 8 seconds.

[0026] The temperature of the constant temperature chamber, and the infrared radiance A within the field of view of the infrared detector. (x，y) The data is transmitted synchronously to the processor.

[0027] The temperature is T. c The infrared radiance value A at each pixel of the first reference film 7, the second reference film 8, and the aerospace component under test in each frame. (x，y) .

[0028] Step 5: Calculate the average infrared radiation brightness L of the first reference plate under constant temperature conditions. c1 (Δλ)

[0029] Select the infrared radiance value A of the consecutive n1 frames obtained in step 4. (x，y) n1 = 100-150 frames.

[0030] Calculate the infrared radiance value A at each pixel of the first reference board in n1 consecutive frames. 1(x，y) The average value, which is the temperature T. c Under the given conditions, within the Δλ band range, the average infrared radiance L at each pixel of the first reference image 7 c1(x,y) (Δλ).

[0031] The average infrared radiance L obtained c1(x,y) (Δλ) is averaged to obtain temperature T. c Under the given conditions, within the Δλ band range, the average infrared radiance L of the first reference plate c1 (Δλ).

[0032] Step 6: Calculate the average infrared radiation brightness L of the second reference plate under constant temperature conditions. c2 (Δλ):

[0033] Select the infrared radiance value A of the consecutive n1 frames obtained in step 4. (x，y) n1 = 100-150 frames.

[0034] Calculate the infrared radiance value A at each pixel of the second reference board in n1 consecutive frames. 1(x，y) The average value, which is the temperature T. c Under the given conditions, within the Δλ band range, the average infrared radiance L at each pixel of the second reference image 8 c2(x,y) (Δλ).

[0035] The average infrared radiance L obtained c2(x,y) (Δλ) is averaged to obtain temperature T. c Under the given conditions, within the Δλ band, the average infrared radiance L of the second reference plate c2 (Δλ).

[0036] Step 7: Calculate the average infrared radiance L of the region corresponding to each pixel of the aerospace component under constant temperature conditions. a(x,y) (Δλ)

[0037] Select the infrared radiance value A of the consecutive n1 frames obtained in step 4. (x，y) n1 = 100-150 frames.

[0038] Calculate the infrared radiance value A at each pixel of the aerospace component under test in n1 consecutive frames. 1(x，y) The average value, which is the temperature T. cUnder the given conditions, within the Δλ band, the average infrared radiance L at each pixel of the tested aerospace component is... a(x,y) (Δλ).

[0039] Step 8: Calculate the infrared emissivity ε of the aerospace component under test in the Δλ band. a(x，y) (Δλ)

[0040] Using the average infrared radiance L obtained from the first reference plate c1 (Δλ), the average infrared radiance L of the second reference plate c2 (Δλ), the average infrared radiance L at each pixel of the aircraft component under test. a(x,y) (Δλ), calculate the infrared emissivity ε of the aerospace component under test in the Δλ band. a(x,y) (Δλ) is calculated as follows:

[0041]

[0042] Get temperature T c Under the given conditions, within the Δλ band, the infrared emissivity ε of the tested aerospace component in the Δλ band. a(x,y) (Δλ).

[0043] Step 9: Draw the surface infrared emissivity map of the aerospace component to be tested.

[0044] Surface infrared emissivity refers to the distribution of infrared emissivity at various locations on the surface of an object. Based on the infrared emissivity ε of the region corresponding to each pixel of the aerospace component under test... a(x,y) (Δλ), representing the infrared emissivity ε of the region corresponding to each pixel. a(x,y) The value of (Δλ) is plotted in a plane coordinate system in a color manner to obtain the distribution map of infrared emissivity of the aircraft component under test in the region corresponding to each pixel point, that is, the surface infrared emissivity map of the aircraft component under test.

[0045] Thus, the surface infrared emissivity map of the aircraft component under test is obtained.

[0046] The above-described method for measuring surface infrared emissivity involves determining the average infrared radiance L of the first reference plate under isothermal conditions. c1 (Δλ), further including:

[0047] The average infrared radiation brightness L of the first reference plate c1 The average calculation process for (Δλ) is as follows:

[0048] The average infrared radiance L at each pixel of the first reference board c1(x,y) (Δλ) is averaged over the first reference plate region to obtain temperature T. c Under the given conditions, within the Δλ band range, the average infrared radiance L of the first reference platec1 (Δλ), the calculation formula is as follows:

[0049]

[0050] In equation (1), ΔS1 is the number of pixels in the first reference plate region, ΔS1 = 496 to 680.

[0051] The above-described method for measuring surface infrared emissivity involves determining the average infrared radiance L of the second reference plate under isothermal conditions. c2 (Δλ), further including:

[0052] The average infrared radiation brightness L of the second reference plate c2 The average calculation process for (Δλ) is as follows:

[0053] The average infrared radiance L at each pixel of the second reference board c2(x,y) (Δλ) is averaged over the second reference plate region to obtain temperature T. c Under the given conditions, within the Δλ band, the average infrared radiance L of the second reference plate c2 (Δλ), the calculation formula is as follows:

[0054]

[0055] In equation (2), ΔS2 is the number of pixels in the second reference plate area, ΔS2 = 496 to 680.

[0056] The beneficial effects of this invention are:

[0057] The surface infrared emissivity measurement device for aerospace components based on a uniform temperature field uses an infrared detector and a constant temperature chamber to generate a surface infrared emissivity map of the target object surface within the field of view of the infrared detector in a single measurement process.

[0058] This method for measuring the surface infrared emissivity of aerospace components based on a uniform temperature field, derived from relevant laws and formulas of infrared physics, eliminates temperature errors by avoiding active irradiation and improves the measurement accuracy of the infrared emissivity of the target object's surface. Using this method, 10 measurements were performed on an aircraft skin sample. The true average emissivity of its low-emissivity infrared coating was 0.353. The measurement results showed an average absolute error of 0.0172 and a maximum absolute error of 0.0224.

[0059] A method for measuring the surface infrared emissivity of aerospace components based on a uniform temperature field is proposed. By using a constant temperature chamber to ensure that the temperature of the aerospace component under test is uniform, the emissivity measurement of curved targets can be realized. Attached Figure Description

[0060] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0061] Figure 1 A schematic diagram of an infrared emissivity measurement device;

[0062] Figure 2 This is a schematic diagram of the reference board;

[0063] Figure 3 This is a schematic diagram of the reference plate and the constant temperature chamber arrangement;

[0064] Figure 4 This is a schematic diagram of the layout of an infrared emissivity measurement device.

[0065] In the diagram: 1. Infrared detector; 2. Platform; 3. Temperature chamber; 4. Processor; 5. Data cable; 6. Reference board; 7. First reference board; 8. Second reference board; 9. Aerospace component under test; 10. Transparent chamber door. Detailed Implementation

[0066] Examples 1, 2, and 3

[0067] An infrared emissivity measurement device for aerospace components based on a uniform temperature field includes an infrared detector 1, a platform 2, a constant temperature chamber 3, a processor 4, a data cable 5, and a reference board 6, such as... Figure 1 As shown.

[0068] like Figure 1 As shown, infrared detector 1 is fixed on platform 2. Infrared detector 1 is connected to processor 4 via data cable 5 and transmits data signals. Incubator 3 is connected to processor 4 via data cable 5 and transmits the temperature of the aircraft component 9 to be tested and the reference plate 6 to processor 4.

[0069] The measurement band of infrared detector 1 is Δλ, which is in the range of 3 to 5 μm. The frame pixel is 640×512, the frame rate is 25 Hz, the integration time is 4490 μs, and the output mode is infrared radiance.

[0070] The constant temperature chamber 3 can be adjusted and maintained within a range of 300 degrees Celsius, and the transparent chamber door 10 faces the infrared detector 1.

[0071] Platform 2 can move horizontally on the ground, and the infrared detector 1 on it can be adjusted up and down.

[0072] A method for measuring the surface infrared emissivity of aerospace components based on a uniform temperature field includes the following steps:

[0073] Step 1, Set up the reference board

[0074] like Figure 2As shown, reference plate 6 includes a first reference plate 7 and a second reference plate 8. The first reference plate 7 is square with a side length of L1, where L1 = 25–40 mm. The first reference plate 7 is a titanium alloy sheet with a uniform infrared emission coating on its front side. The infrared emissivity of this coating in the wavelength range of 3–5 μm is ε. c1 , where ε c1 =0.395~0.465; The second reference plate 8 is a square with the same side length as the first reference plate 7. The second reference plate 8 is a titanium alloy metal sheet with a uniform infrared radiation coating on the front. The infrared emissivity of this coating in the wavelength range of 3~5μm is ε c2 , where ε c2 =0.505~0.585.

[0075] like Figure 3 As shown, the reference plate 6 and the aircraft component 9 to be tested are placed inside the constant temperature chamber 3. The bottom edge of the reference plate 6 is flush with the bottom edge of the aircraft component 9 to be tested. The front end of the aircraft component 9 to be tested is located in the plane of the reference plate 6. The front of the reference plate 6 is placed facing the infrared detector 1. The normal direction of the front of the reference plate 6 is directly facing the infrared detector 1. Both the reference plate 6 and the aircraft component 9 to be tested are within the field of view of the infrared detector 1.

[0076] Step 2, install the aircraft component to be tested 9

[0077] like Figure 4 As shown, the aircraft component 9 to be tested is located within the field of view of the infrared detector 1. The aircraft component 9 to be tested is placed inside the constant temperature chamber 3. The distance from the lens of the infrared detector to the foremost point of the aircraft component 9 to be tested is L2, where L2 = 1500~2500mm.

[0078] The front of the aircraft component 9 to be tested and the front of the reference plate 6 appear simultaneously in the field of view of the infrared detector 1. The number of pixels on the front of the first reference plate 7 in the field of view of the infrared detector is ΔS1, ΔS1 = 496~680; the number of pixels on the front of the second reference plate 8 in the field of view of the infrared detector is ΔS2, ΔS2 = 496~680.

[0079] Step 3: Establish the view plane coordinate system of infrared detector 1

[0080] The aircraft component 9 to be tested and the reference plate 6 are projected onto the viewing plane of the infrared detector 1. A Cartesian coordinate system is established with the lower left pixel of the infrared detector 1 as the origin. The viewing plane of the infrared detector 1 is divided into grids so that each pixel of the infrared detector 1 is located on a grid node.

[0081] Step 4: Collect the infrared radiation brightness value A of the corresponding area of ​​each pixel under constant temperature conditions. (x,y)

[0082] Turn on the surface infrared emissivity measuring device, and control the temperature of the constant temperature chamber 3 to a certain temperature.

[0083] The infrared detector 1 is set to collect data within the field of view, with the front of the reference plate 6 and the aircraft component 9 to be tested as the field of view; the front area of ​​the first reference plate 7 is S1, the front area of ​​the second reference plate 8 is S2, and the area of ​​the aircraft component 9 to be tested is S3.

[0084] Infrared detector 1 enters a stable working state, simultaneously acquiring the infrared radiation brightness of the corresponding areas of each pixel on the front of the first reference plate 7, the second reference plate 8, and the aircraft component under test 9. The acquisition time is t1, where t1 = 6-8s. The acquired infrared radiation brightness of the corresponding areas of each pixel on the front of the first reference plate 7, the second reference plate 8, and the aircraft component under test 9 is transmitted to processor 4 via data cable 5, obtaining the infrared radiation brightness value A of the corresponding areas of each pixel on the front of the first reference plate 7, the second reference plate 8, and the aircraft component under test 9 under this condition at a wavelength of 3-5μm. (x,y) .

[0085] The constant temperature chamber 3 transmits the temperatures T of the first reference plate 7, the second reference plate 8, and the aircraft component 9 to be tested via data cable 5. c The data is transmitted to the processor 4.

[0086] Step 5: Calculate the average infrared radiation brightness L of the first reference plate 7 under constant temperature conditions. c1(Δλ)

[0087] The infrared radiance value A of the corresponding area of ​​each pixel on the front side of the first reference plate 7 under constant temperature conditions obtained in step 4, with a wavelength of 3-5 μm. (x,y) The data is processed using the following methods:

[0088] Select the infrared radiance value A of the corresponding area of ​​each pixel on the front side of the first reference board 7 in the steady state of n1 consecutive frames obtained in step 4. 1(x,y) Given a continuous frame count n1 = 100-150 frames, the average value is calculated to obtain the average infrared radiation brightness L of the corresponding area of ​​each pixel on the front side of the first reference plate 7 under constant temperature conditions. c1(x,y) (Δλ);

[0089] Using the average infrared radiation brightness L of the corresponding area of ​​each pixel on the front side of the first reference board 7 under constant temperature conditions c1(x，y) (Δλ), by solving according to equation (1), the average infrared radiation brightness L of the area corresponding to each pixel on the front of the first reference plate 7 is obtained. c1 (Δλ).

[0090]

[0091] Where Δλ represents the 3–5 μm band, L c1(x，y)(Δλ) is the average infrared radiation brightness of the area corresponding to each pixel on the front of the first reference plate 7 under constant temperature conditions, and ΔS1 is the number of pixels in the front area of ​​the first reference plate 7, ΔS1=496~680.

[0092] Thus, the average infrared radiation brightness L of the first reference plate 7 under constant temperature conditions was obtained. c1 (Δλ).

[0093] Step 6: Calculate the average infrared radiation brightness L of the second reference plate 8 under constant temperature conditions. c2 (Δλ)

[0094] The infrared radiance value A of the corresponding area of ​​each pixel on the front side of the constant temperature plate 8 obtained in step 4 at a wavelength of 3-5 μm. (x，y) The data is processed using the following methods:

[0095] Select the infrared radiance value A of the corresponding region of each pixel on the front side of the second reference board 8 in the steady state of n1 consecutive frames obtained in step 4. 2(x，y) Given a continuous frame count n1 = 100-150 frames, the average value is calculated to obtain the average infrared radiation brightness L of the corresponding area of ​​each pixel on the front side of the second reference plate 8 under constant temperature conditions. c2(x，y) (Δλ);

[0096] Using the average infrared radiation brightness L of the corresponding area of ​​each pixel on the front side of the second reference board 8 under constant temperature conditions c1(x，y) (Δλ), by solving according to equation (2), the average infrared radiation brightness L of the area corresponding to each pixel on the front of the second reference plate 8 is obtained. c2 (Δλ).

[0097]

[0098] Where Δλ represents the 3–5 μm band, L c2(x，y) (Δλ) is the average infrared radiation brightness of the area corresponding to each pixel on the front of the second reference plate 8 under constant temperature conditions, and ΔS2 is the number of pixels in the front area of ​​the second reference plate 8, ΔS2=496~680.

[0099] Thus, the average infrared radiation brightness L of the second reference plate 8 under constant temperature conditions was obtained. c2 (Δλ).

[0100] Step 7: Calculate the average infrared radiance L of the corresponding area of ​​each pixel point of the aerospace component 9 under constant temperature conditions. a(x，y) (Δλ)

[0101] The infrared radiance value A of the corresponding region of each pixel point of the aerospace component 9 under constant temperature conditions obtained in step 4 is measured at a wavelength of 3-5 μm. (x，y) The data is processed using the following methods:

[0102] Select the infrared radiance values ​​A of each pixel of the aircraft component 9 under test in the steady state of n3 consecutive frames obtained in step 4. 3(x，y) Given 100-150 consecutive frames, calculate the average value to obtain the average infrared radiance L at each pixel of the tested aerospace component 9 under constant temperature conditions. a(x，y) (Δλ).

[0103] Step 8: Calculate the infrared emissivity ε of the tested aerospace component 9 in the Δλ band. a(x，y) (Δλ)

[0104] The average infrared radiation L of the first reference plate 7 under constant temperature conditions obtained in step 5 c1 (Δλ), the average infrared radiation L of the second reference plate 8 under isothermal conditions obtained in step 6. c2 (Δλ), the average infrared radiance L of the corresponding region of each pixel point of the aerospace component 9 under constant temperature conditions obtained in step 7. a(x，y) (Δλ), calculated using equation (3):

[0105]

[0106] In equation (3), The value is the average infrared radiance of the region corresponding to the (x, y) pixel point of the aircraft component 9 under test in the Δλ band. The average infrared radiation brightness of the first reference plate 7 itself. Let ε be the average infrared radiance of the second reference plate 8. Simplify the system of equations according to equation (3), eliminate unknown terms, and obtain the infrared emissivity ε of each pixel in the coating area of ​​the aircraft under test. a(x，y) The expression for (Δλ) is (4).

[0107]

[0108] The right side of equation (4) represents the measured or known value. The infrared emissivity ε of the region corresponding to each pixel of the aircraft component to be tested can be obtained by calculation. a(x，y) (Δλ).

[0109] Step 9: Draw the surface infrared emissivity map of the aerospace component 9 to be tested.

[0110] Surface infrared emissivity is the distribution of infrared emissivity at various locations on the surface of an object. Based on the infrared emissivity ε of the corresponding region for each pixel of the aerospace component 9 under test obtained in step 7... a(x，y) (Δλ), representing the infrared emissivity ε of the region corresponding to each pixel. a(x，y)The value of (Δλ) is plotted in a plane coordinate system in a color manner to obtain the distribution map of infrared emissivity of the aircraft component 9 under test in the corresponding area of ​​each pixel point, that is, the surface infrared emissivity map of the aircraft component 9 under test.

[0111] Thus, the surface infrared emissivity map of the aircraft component 9 to be tested is obtained.

[0112] Table 1 Relevant Parameters

[0113] Example 1 Example 2 Example 3 <![CDATA[L1 / mm]]> 25 35 40 <![CDATA[ε c1 ]]> 0.395 0.425 0.465 <![CDATA[ε c2 ]]> 0.505 0.545 0.585 <![CDATA[L2 / mm]]> 1500 2000 2500 <![CDATA[ΔS1]]> 680 550 496 <![CDATA[ΔS2]]> 680 550 496 <![CDATA[t1 / s]]> 6 7 8 <![CDATA[T c / ℃]]> 250 300 230 <![CDATA[n1]]> 100 125 150 .

Claims

1. A device for measuring the infrared emissivity of an aerospace component surface based on a uniform temperature field, characterized in that, It mainly includes an infrared detector (1), a platform (2), a constant temperature chamber (3), a processor (4), a data cable (5), and a reference board (6); the processor (4) is connected to the infrared detector (1) and the constant temperature chamber (3) respectively through the data cable (5) and transmits signals; the infrared detector (1) is located on the platform (2) and is used to collect the infrared radiation brightness of the aircraft component (9) under test; the reference board (6) and the aircraft component under test are located in the constant temperature chamber (3); The temperature control chamber (3) has a temperature range of 30 to 300°C and maintains a constant temperature. The transparent door (10) of the temperature control chamber (3) faces the infrared detector (1). The infrared detector (1) can collect the infrared radiation brightness of the aircraft component (9) under test and the reference plate (6) inside the temperature control chamber (3) through the transparent door (10). The reference plate (6) has an infrared radiation coating on one side and includes a first reference plate (7) and a second reference plate (8). The first reference plate (7) and the second reference plate (8) are placed one above the other and located on one side of the aircraft component (9) under test. The surfaces of the first reference plate (7) and the second reference plate (8) with infrared radiation coating are the front surfaces, which face the direction of the infrared detector (1). The normals at the center points of the front surfaces of the first reference plate (7) and the second reference plate (8) both pass through the midpoint of the lens of the infrared detector (1). The center point of the front of the first reference plate (7) and the second reference plate (8) are equidistant from the center point of the lens of the infrared detector (1), both being L2, where L2 = 1500~2500mm.

2. The infrared emissivity measurement device for aerospace components based on a uniform temperature field according to claim 1, characterized in that, The infrared detector (1) measures in the band Δλ, which is in the range of 3 to 5 μm. The frame pixel is 640×512, the frame rate is 25 Hz, the integration time is 4490 μs, and the output mode is infrared radiation brightness.

3. The infrared emissivity measurement device for aerospace components based on a uniform temperature field according to claim 1, characterized in that, Both the first reference plate (7) and the second reference plate (8) are square plates with equal side lengths, both being L1, where L1 = 25~40mm; within a wavelength range of 3~5μm, the infrared emissivity of the front side of the first reference plate (7) is εc1, where εc1 = 0.395~0.465, and the infrared emissivity of the front side of the second reference plate (8) is εc2, where εc2 = 0.505~0.

585.

4. A method for measuring the surface infrared emissivity of an aerospace component using the uniform temperature field-based surface infrared emissivity measuring device according to any one of claims 1 to 3, characterized in that, Includes the following steps: Step 1, set up the reference board (6): Place the first reference plate (7) and the second reference plate (8) in a constant temperature chamber (3), and adjust the first reference plate (7) and the second reference plate (8) so that the normals at the center points of the front of the first reference plate (7) and the second reference plate (8) both pass through the midpoint of the lens of the infrared detector (1); the distances from the center points of the front of the first reference plate (7) and the second reference plate (8) to the midpoint of the lens of the infrared detector (1) are equal, both being L2, where L2 = 1500~2500mm; Step 2, install the aircraft component to be tested (9): The aircraft component (9) to be tested is installed in the constant temperature chamber (3). The infrared radiation direction of the aircraft component is the test direction, so that the test direction of the aircraft component (9) is facing the lens of the infrared detector (1). The minimum distance between the aircraft component (9) to be tested and the midpoint of the lens of the infrared detector (1) is equal to L2. Step 3, establish the view plane coordinate system of the infrared detector (1): Project the aircraft component (9) to be tested and the reference plate (6) onto the viewing plane of the infrared detector (1), and establish a plane rectangular coordinate system with the lower left corner pixel of the infrared detector (1) as the origin. Divide the viewing plane of the infrared detector (1) into a grid so that each pixel of the infrared detector (1) is located on a grid node. Step 4: Collect the infrared radiance value A(x,y) of the corresponding region of each pixel under constant temperature conditions: Turn on the surface infrared emissivity measuring device and adjust the temperature of the constant temperature chamber (3) to Tc, Tc = 230~300℃, so that the temperature of the first reference plate (7), the second reference plate (8) and the aircraft component to be tested (9) are all Tc; Adjust the infrared detector (1) so that the first reference plate (7), the second reference plate (8), and the aircraft component (9) to be tested are all within the field of view of the infrared detector (1). The front area of ​​the first reference plate (7) is S1, the front area of ​​the second reference plate (8) is S2, and the area of ​​the aircraft component (9) to be tested is S3. The infrared detector (1) enters a stable working state. Within the measurement band Δλ range, Δλ = 3 to 5 μm, it simultaneously collects the infrared radiation brightness A(x,y) at each pixel point of the first reference plate (7), the second reference plate (8), and the aircraft component under test (9) within the field of view. The collection time is t1, t1 = 6 to 8 s. The temperature of the constant temperature chamber (3) and the infrared radiation brightness A(x,y) in the field of view of the infrared detector (1) are synchronously transmitted to the processor (4) to obtain the infrared radiation brightness value A(x,y) of each pixel point of the first reference plate (7), the second reference plate (8), and the aircraft component under test (9) when the temperature is Tc. Step 5, calculate the average infrared radiance Lc1(Δλ) of the first reference plate (7) under constant temperature conditions: select the infrared radiance values ​​A(x,y) of n1 consecutive frames obtained in step 4, n1=100~150 frames; The average value of infrared radiation brightness A1(x,y) at each pixel of the first reference plate (7) in consecutive n1 frames is obtained. This average value is the average infrared radiation brightness Lc1(x,y) (Δλ) at each pixel of the first reference plate (7) under the temperature Tc condition and within the Δλ band range. The average infrared radiance Lc1(x,y) (Δλ) obtained is used to calculate the average infrared radiance Lc1 (Δλ) of the first reference plate (7) under temperature Tc and within the Δλ band. Step 6: Calculate the average infrared radiance Lc2(Δλ) of the second reference plate (8) under constant temperature conditions: Select the infrared radiance values ​​A(x, y) of n1 consecutive frames obtained in step 4, where n1 = 100 to 150 frames; The average value of infrared radiation brightness A1(x,y) at each pixel of the second reference board (8) in consecutive n1 frames is obtained. This average value is the average infrared radiation brightness Lc2(x,y) (Δλ) at each pixel of the second reference board (8) under the temperature Tc condition and within the Δλ band. The average infrared radiance Lc2(x,y) (Δλ) obtained is used to calculate the average infrared radiance Lc2(Δλ) of the second reference plate (8) under the temperature Tc condition within the Δλ band. Step 7, calculate the average infrared radiance La(x, y)(Δλ) of the region corresponding to each pixel of the aerospace component (9) under constant temperature conditions: Select the infrared radiance values ​​A(x, y) of n1 consecutive frames obtained in step 4, where n1 = 100 to 150 frames; The average value of infrared radiation brightness A1(x,y) at each pixel of the aircraft component (9) under test in consecutive n1 frames is obtained. This average value is the average infrared radiation brightness La(x,y)(Δλ) at each pixel of the aircraft component (9) under test in the Δλ band under temperature Tc. Step 8, calculate the infrared emissivity εa(x,y) (Δλ) of the tested aerospace component (9) in the Δλ band: Using the average infrared radiance Lc1 (Δλ) of the first reference plate (7), the average infrared radiance Lc2 (Δλ) of the second reference plate (8), and the average infrared radiance La(x,y) (Δλ) at each pixel of the aircraft component (9) under test, the infrared emissivity εa(x,y) (Δλ) of the aircraft component (9) under test in the Δλ band is calculated as follows: Under temperature Tc, the infrared emissivity εa(x,y)(Δλ) of the tested aerospace component (9) in the Δλ band is obtained. Step 9: Draw the surface infrared emissivity map of the aerospace component (9) to be tested: Surface infrared emissivity refers to the distribution of infrared emissivity at various locations on the surface of an object. Based on the infrared emissivity εa(x,y) (Δλ) of the region corresponding to each pixel of the aircraft component (9) to be tested, the values ​​of infrared emissivity εa(x,y) (Δλ) of the region corresponding to each pixel are plotted in a plane coordinate system in a color manner to obtain the distribution map of infrared emissivity of the aircraft component (9) to be tested in the region corresponding to each pixel, that is, the surface infrared emissivity map of the aircraft component (9) to be tested. Thus, the surface infrared emissivity map of the aircraft component (9) to be tested is obtained.

5. The method for measuring the surface infrared emissivity of aerospace components using the uniform temperature field-based surface infrared emissivity measuring device according to claim 4, characterized in that, The determination of the average infrared radiance Lc1 (Δλ) of the first reference plate (7) under constant temperature conditions further includes: The average infrared radiance Lc1(Δλ) of the first reference plate (7) is calculated as follows: The average infrared radiance Lc1(x, y) (Δλ) at each pixel of the first reference plate (7) is averaged over the region of the first reference plate (7) to obtain the average infrared radiance Lc1(Δλ) of the first reference plate (7) under the temperature Tc condition within the Δλ band. The calculation formula is as follows: In equation (1), ΔS1 is the number of pixels in the region of the first reference plate (7), ΔS1 = 496 to 680.

6. The method for measuring the surface infrared emissivity of aerospace components using the uniform temperature field-based surface infrared emissivity measuring device according to claim 4, characterized in that, The determination of the average infrared radiance Lc2(Δλ) of the second reference plate (8) under constant temperature conditions further includes: The average infrared radiance Lc2(Δλ) of the second reference plate (8) is calculated as follows: The average infrared radiance Lc2(x, y) (Δλ) at each pixel of the second reference plate (8) is averaged over the region of the second reference plate (8) to obtain the average infrared radiance Lc2(Δλ) of the second reference plate (8) under the temperature Tc condition within the Δλ band. The calculation formula is as follows: In equation (2), ΔS2 is the number of pixels in the region of the second reference plate (8), ΔS2 = 496 to 680.

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