A method and system for measuring film cooling effectiveness based on parallel line light source scanning

Abstract

The application discloses a kind of gas film cooling efficiency measurement method and system based on parallel line light source scanning, it is related to the technical field of cooling characteristic measurement of aero-engine hot end component, method includes: the relationship between the light intensity of pressure sensitive paint after excitation and oxygen partial pressure is obtained by calibration;Pressure sensitive paint is sprayed to the surface of the model to be measured, and four specific scenarios are constructed, the surface of the model to be measured is scanned using parallel line light source in three of which scenarios, and a scientific camera is used to take pictures, to obtain a series of images;The series of images are processed to obtain the light intensity value of the fluorescence emitted by the pressure sensitive paint under four scenarios;Based on the light intensity value and the relationship, the surface gas film cooling efficiency of the model to be measured is calculated.The application uses parallel light source scanning and image processing, can avoid the fluorescence emitted by surrounding pressure sensitive paint, eliminate the influence of fluorescent reflection on light intensity when using a scientific camera to take pictures, correct the deviation of using pressure sensitive paint to measure gas film cooling efficiency.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology of cooling characteristics of hot-end components of aero-engines, and specifically relates to a method and system for measuring film cooling efficiency based on parallel line light source scanning. Background Technology

[0002] Turbine engines, including ground-based gas turbines and aero engines, possess advantages such as high cycle efficiency. The working principle of turbine engines is based on the actual Brayton cycle, which means that increasing the turbine inlet temperature directly improves cycle efficiency. In current advanced aero engines, the turbine inlet temperature far exceeds the temperature limit of turbine blades during long-term operation; therefore, efficient cooling technology is one of the key technologies for turbine engines. Among these, film cooling technology is widely used. This involves creating discrete film cooling holes on a solid surface, guiding cooling gas from the inner cavity to the outer wall surface that is in direct contact with the high-temperature combustion gases. Under the action of the mainstream high-temperature combustion gases, the cooling gas forms a thin film on the solid surface. The temperature of this film is lower than that of the mainstream combustion gases, thus achieving high-temperature insulation.

[0003] The thermal insulation film cooling efficiency, or film cooling effect for short, is a dimensionless expression of the temperature after the mainstream combustion gas and cold gas are mixed under the hypothetical condition of solid wall insulation. The film cooling effect directly represents the effectiveness of the film in insulating against high temperatures and is a crucial parameter for evaluating the cooling effect. A value of 1 indicates that the insulation layer temperature equals the cooling gas temperature, resulting in the best cooling effect; a value of 0 indicates that the insulation layer temperature equals the mainstream temperature, with no cooling effect.

[0004] The measurement methods for film cooling efficiency are mainly divided into heat transfer measurement methods and mass transfer analogy methods. Heat transfer measurement methods include steady-state and transient measurement methods, which measure the surface temperature of a solid under heat exchange conditions, and are therefore inevitably affected by thermal conduction. Mass transfer analogy methods, on the other hand, utilize the consistency between the mass transfer equation and the heat transfer equation, using the dimensionless result of mass exchange to replace the dimensionless result of heat exchange, thus eliminating the influence of thermal conduction. Pressure-sensitive paint (PSP), which can measure oxygen partial pressure, is widely used in film cooling efficiency measurement because it can measure mass transfer results. Based on the oxygen quenching effect, PSP, after being irradiated with excitation light, can provide the surrounding oxygen partial pressure by measuring the intensity of the emitted fluorescence. The method for measuring the film cooling efficiency of PSP based on the mass transfer analogy theory was first proposed by Zhang et al. in "Flat Plate Film Cooling Measurements using PSP Gas Chromatograph Techniques". The principle of measuring the efficiency of thermal insulation film cooling using pressure-sensitive paint can be summarized as follows: using air as the main stream and an oxygen-free heterogeneous gas as the jet, the mass fraction of the jet after the main stream and the jet are mixed is measured using pressure-sensitive paint.

[0005] In the actual experiment, four specific scenarios need to be constructed: Scenario 1: Excitation light off, no flow, i.e., a dark environment. The purpose is to eliminate the influence of ambient light and obtain more accurate light intensity data. Scenario 2: Excitation light irradiated, no flow. This condition is called the reference condition, and its purpose is to make the light intensity results dimensionless. The dimensionless light intensity and dimensionless oxygen partial pressure are related, and their relationship is obtained in the calibration experiment. Scenario 3: Excitation light irradiated, with the main stream and jet both set to air. The purpose is to obtain the local static pressure. Scenario 4: Excitation light irradiated, with the main stream set to air and the jet a heterogeneous gas without oxygen. The purpose is to obtain the local oxygen partial pressure.

[0006] In all four scenarios, light intensity images were obtained by photographing the surface of the test model coated with pressure-sensitive paint using a scientific camera. A two-dimensional image can be understood as a light intensity matrix. From the four light intensity matrices of the four images, two oxygen partial pressure matrices are derived, from which the film cooling efficiency matrix is ​​calculated. Therefore, whether the light intensity result obtained at any point in the image accurately reflects the fluorescence emitted by the pressure-sensitive paint becomes one of the decisive factors in determining the accuracy of the film cooling efficiency measurement.

[0007] In applications of film cooling, there are concave surfaces, including the pressure surface of turbine blades and the inner surface of the outer casing; there are also scenarios where multiple surfaces are opposite each other, such as the turbine blade body and turbine blade endwall, or the turbine blade tip and outer casing. In these scenarios, when measuring the fluorescence intensity emitted by pressure-sensitive paint at a certain point using a scientific camera, fluorescence emitted by pressure-sensitive paint at other locations will be diffusely reflected from that location before entering the camera lens. The result obtained by the scientific camera is not the actual fluorescence intensity emitted by the local pressure-sensitive paint, causing measurement deviation.

[0008] In summary, when using pressure-sensitive paint to measure the film cooling efficiency, the light intensity measurement deviation caused by fluorescence reflection will lead to deviations in the film cooling efficiency results. Therefore, the measurement method needs to be improved. Summary of the Invention

[0009] This invention aims to address the shortcomings of existing technologies and provides the following solutions:

[0010] A method for measuring film cooling efficiency based on parallel line light source scanning includes the following steps:

[0011] The relationship between the light intensity and oxygen partial pressure of the pressure-sensitive paint after excitation was obtained by calibration.

[0012] The pressure-sensitive paint was sprayed onto the surface of the model to be measured, and four specific scenarios were constructed. In three of these scenarios, a parallel line light source was used to scan the surface of the model to be measured, and a scientific camera was used to take pictures to obtain a series of images. The four specific scenarios include: Scenario 1: Excitation light off, no gas flow, corresponding to a dark environment; Scenario 2: Excitation light irradiated, no gas flow, corresponding to reference conditions; Scenario 3: Excitation light irradiated, with the main stream and jet set to air; Scenario 4: Excitation light irradiated, with the main stream set to air and the jet set to an oxygen-free heterogeneous gas.

[0013] The series of images were processed to obtain the light intensity values ​​of the fluorescence emitted by the pressure-sensitive paint under four different scenarios;

[0014] Based on the light intensity value and the relationship, the surface air film cooling efficiency of the model to be measured is calculated.

[0015] Preferably, the method for obtaining the relation includes:

[0016] Inside a sealed cavity, the pressure-sensitive paint is irradiated with excitation light while the oxygen partial pressure inside the cavity is continuously changed. The light intensity and oxygen partial pressure values ​​are recorded to obtain the following relationship:

[0017]

[0018] Among them, I ref This represents the light intensity value under reference conditions. T represents the partial pressure of oxygen under reference conditions. ref I represents the temperature value under reference conditions, I1 represents the light intensity value in a dark environment, x represents the conditions at a certain moment during the calibration process, and I x This indicates the light intensity value during the calibration process. The value represents the oxygen partial pressure during the calibration process, and f represents the functional relationship between the light intensity, partial pressure, and temperature.

[0019] Preferably, in the second, third, and fourth scenarios, the parallel line light source is used to scan the surface of the model to be measured. The parallel line light source scans along the surface, and a scientific camera is used to take pictures during the scanning process to obtain a series of images.

[0020] Preferably, the method for processing the series of images includes:

[0021] Record the light intensity of the fluorescent region in each image in the series of images;

[0022] The light intensity results of the series of images are stitched together, the positions of the light intensity results are repeatedly recorded, and the average value of the light intensity results is taken to obtain the light intensity value.

[0023] Preferably, the method for calculating the surface film cooling efficiency includes:

[0024] The light intensity matrix captured in the first scene is taken as the light intensity value I1 in the dark environment, and the light intensity matrix captured in the second scene is taken as the light intensity value I under the reference condition. ref The light intensity matrix captured in the third scene is used as the light intensity value I3 in the third calibration process, the light intensity matrix captured in the fourth scene is used as the light intensity value I4 in the fourth calibration process, and the oxygen partial pressure matrix set under the reference conditions is used as the oxygen partial pressure value. Solve the oxygen partial pressure matrix in the third scenario using the aforementioned relationship. The oxygen partial pressure matrix in the fourth scenario

[0025] Obtain the molecular weight W of the heterogeneous gas fg and the molecular weight W of the air air Based on the oxygen partial pressure matrix in the third scenario and the oxygen partial pressure matrix in the fourth scenario Calculate the surface film cooling efficiency:

[0026]

[0027] Where η represents the surface air film cooling efficiency.

[0028] The present invention also provides a gas film cooling efficiency measurement system based on parallel line light source scanning. The measurement system applies the measurement method described above and includes: a calibration module, an image acquisition module, an image processing module, and an efficiency calculation module.

[0029] The calibration module obtains the relationship between the light intensity and oxygen partial pressure of the pressure-sensitive paint after it is excited by calibration.

[0030] The image acquisition module sprays the pressure-sensitive paint onto the surface of the model to be measured and constructs four specific scenarios. In three of these scenarios, a parallel line light source is used to scan the surface of the model to be measured, and a scientific camera is used to capture images, resulting in a series of images. The four specific scenarios include: Scenario 1: Excitation light off, no gas flow, corresponding to a dark environment; Scenario 2: Excitation light irradiated, no gas flow, corresponding to reference conditions; Scenario 3: Excitation light irradiated, with the main stream and jet being air; Scenario 4: Excitation light irradiated, with the main stream being air and the jet being an oxygen-free heterogeneous gas.

[0031] The image processing module is used to process the series of images to obtain the light intensity values ​​of the fluorescence emitted by the pressure-sensitive paint under four scenarios;

[0032] The efficiency calculation module calculates the surface air film cooling efficiency of the model to be measured based on the light intensity value and the relationship.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] This invention utilizes parallel light source scanning and image processing to avoid fluorescence emitted by the surrounding pressure-sensitive paint, eliminates the influence of fluorescence reflection on light intensity when using a scientific camera, and corrects the deviation in measuring the film cooling efficiency using pressure-sensitive paint. Attached Figure Description

[0035] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the method flow according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the experimental apparatus according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram illustrating the processing of the image obtained during the scanning process according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the system structure according to an embodiment of the present invention;

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Unilluminated area to be measured; 2. Area irradiated by excitation light; 3. Non-measurement area; 4. Excitation light; 5. Main stream; 6. Scientific camera; 7. Air film pore; 8. Jet; 9. Excitation light source; 10. Light source scanning drive mechanism; 11. Measurement area. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] In this embodiment, as Figure 1 As shown, a method for measuring film cooling efficiency based on parallel line light source scanning includes the following steps:

[0046] S1. The relationship between the light intensity and oxygen partial pressure of the pressure-sensitive paint after excitation is obtained through calibration.

[0047] The method for obtaining the relationship includes: irradiating the pressure-sensitive paint with excitation light 4 inside a sealed cavity and continuously changing the oxygen partial pressure inside the cavity, recording the light intensity and oxygen partial pressure values ​​to obtain the relationship:

[0048]

[0049] The calibration process includes setting reference conditions, typically atmospheric pressure. ref This represents the light intensity value under reference conditions. T represents the partial pressure of oxygen under reference conditions. ref I represents the temperature value under reference conditions, I1 represents the light intensity value in a dark environment, x represents the conditions at a certain moment during the calibration process, and I x This indicates the light intensity value during the calibration process. The value represents the oxygen partial pressure during the calibration process, and f represents the functional relationship between the light intensity, partial pressure, and temperature.

[0050] S2. Apply pressure-sensitive paint to the surface of the model to be measured, construct four specific scenarios, and use a parallel line light source to scan the surface of the model to be measured in three of the scenarios, and take pictures using a scientific camera 6 to obtain a series of images; the four specific scenarios include: the first scenario: the excitation light 4 is off, there is no gas flow, corresponding to a dark environment; the second scenario: the excitation light 4 is irradiated, there is no gas flow, corresponding to the reference conditions; the third scenario: the excitation light 4 is irradiated, and the main stream 5 is set to air and the jet 8 is air; the fourth scenario: the excitation light 4 is irradiated, and the main stream 5 is set to air and the jet 8 is a heterogeneous gas without oxygen.

[0051] In the second, third, and fourth scenes, parallel line light sources are used to scan the measurement area 11 of the model under test. The area 2 illuminated by the excitation light 4 within the measurement area 11 emits fluorescence. The unilluminated area 1 within the measurement area 11 is the area not illuminated by the excitation light 4 and does not emit fluorescence. During the scanning process, a scientific camera 6 is continuously used to take pictures until the scanning is completed, resulting in a series of images.

[0052] S3. Process the series of images to obtain the light intensity values ​​of the fluorescence emitted by the pressure-sensitive paint under four scenarios.

[0053] Methods for processing a series of images include: Figure 3As shown, the light intensity results of the excitation light irradiation area 2 in a single image of the series of images are recorded; the light intensity results of the series of images are stitched together, the positions of the light intensity results are repeatedly recorded and the average value of the light intensity results is taken to obtain the light intensity value of the fluorescence emitted by the pressure-sensitive paint in the measurement area 11 after excitation.

[0054] S4. Based on the light intensity value and the relationship, the surface air film cooling efficiency of the model to be measured is calculated.

[0055] The method for calculating the surface film cooling efficiency includes: using the light intensity matrix captured in the first scene as the light intensity value I1 in the dark environment, and using the light intensity matrix captured in the second scene as the light intensity value I under the reference condition. ref The light intensity matrix captured in the third scene is used as the light intensity value I3 in the third calibration process, and the light intensity matrix captured in the fourth scene is used as the light intensity value I4 in the fourth calibration process. The oxygen partial pressure matrix set under the reference conditions is used as the oxygen partial pressure value. Solve the oxygen partial pressure matrix in the third scenario using the relational formula. Oxygen partial pressure matrix in the fourth scenario Obtain the molecular weight W of the heterogeneous gas fg The molecular weight W of air air And based on the oxygen partial pressure matrix in the third scenario and the oxygen partial pressure matrix in the fourth scenario Calculate the surface film cooling efficiency:

[0056]

[0057] Where η represents the surface air film cooling efficiency.

[0058] Example 2

[0059] In this embodiment, as Figure 2 As shown, a gas film cooling efficiency measurement device based on parallel line light source scanning is provided, including: an unilluminated test area 1, an excitation light irradiated area 2, a non-measurement area 3, an excitation light 4, a main stream 5, a scientific camera 6, a gas film aperture 7, a jet 8, an excitation light source 9, a light source scanning drive mechanism 10, and a measurement area 11. The measurement area 11 is the area coated with pressure-sensitive paint. The unilluminated test area 1 and the excitation light irradiated area 2 together constitute the measurement area 11. The main stream 5 is air, and the jet 8 is a heterogeneous gas or air.

[0060] Its workflow is as follows:

[0061] (1) Before measurement, the relationship between the fluorescence intensity emitted by the pressure-sensitive paint after excitation by excitation light 4 and the oxygen partial pressure was obtained through calibration:

[0062]

[0063] The calibration process includes setting reference conditions, typically atmospheric pressure. ref This represents the light intensity value under reference conditions. T represents the partial pressure of oxygen under reference conditions. ref I represents the temperature value under reference conditions, I1 represents the light intensity value in a dark environment, x represents the conditions at a certain moment during the calibration process, and I x This indicates the light intensity value during the calibration process. The value represents the oxygen partial pressure during the calibration process, and f represents the functional relationship between the light intensity, partial pressure, and temperature.

[0064] (2) Apply pressure-sensitive paint to the measurement area 11 on the model surface and apply black paint to the non-measurement area 3.

[0065] (3) Construct four specific scenarios:

[0066] Scene 1: Turn off excitation light 4, turn off mainstream 5 and jet 8, obtain ambient light, and take pictures using a scientific camera 6 in a fixed position;

[0067] Second scenario: Turn off the main stream 5 and the jet 8, turn on the excitation light source 9, use the light source scanning drive mechanism 10 to make the excitation light 4 scan along the measurement area 11, and use a scientific camera 6 in a fixed position to take pictures during the process. The shooting results of this scenario correspond to the reference conditions.

[0068] Third scenario: Set the main stream 5 to be air and the jet 8 to be air. The main stream 5 is connected to the jet 8. The jet 8 flows out through the air film hole 7. Turn on the excitation light source 9. Use the light source scanning drive mechanism 10 to make the excitation light 4 scan along the measurement area 11. During the process, use a scientific camera 6 in a fixed position to take pictures.

[0069] Fourth scenario: Set the main stream 5 to be air and the jet 8 to be a heterogeneous gas. The main stream 5 is circulated through the jet 8, and the jet 8 flows out through the gas film hole 7. Turn on the excitation light source 9, and use the light source scanning drive mechanism 10 to make the excitation light 4 scan along the measurement area 11. During the process, a scientific camera 6 with a fixed position is used to take pictures.

[0070] (4) Figure 3As shown, the series of images obtained in the second, third, and fourth scenarios in step (3) are processed. The non-measurement area 3 is not coated with pressure-sensitive paint and therefore does not fluoresce. The excitation light-irradiated area 2 is the area within measurement area 11 irradiated by excitation light 4 and fluoresces. The unirradiated test area 1 is the area within measurement area 11 not irradiated by excitation light 4 and does not fluoresce. Therefore, the excitation light-irradiated area 2 in the series of images captured by the scientific camera 6 is stitched together, and the average value of the repeatedly recorded data positions is taken to finally obtain the light intensity result of the fluorescence emitted by the pressure-sensitive paint in measurement area 11 after excitation.

[0071] (5) Based on the light intensity results and the relationship between light intensity and oxygen partial pressure, the oxygen partial pressure results for measurement area 11 in the third and fourth scenes are obtained. When using the relationship, the light intensity matrix captured in the first scene is taken as the light intensity value I1 in the dark environment, and the light intensity matrix captured in the second scene is taken as the light intensity value I under the reference condition. ref The light intensity matrix captured in the third scene is used as the light intensity value I3 in the third calibration process, and the light intensity matrix captured in the fourth scene is used as the light intensity value I4 in the fourth calibration process. The oxygen partial pressure matrix set under the reference conditions is used as the oxygen partial pressure value. Solve the oxygen partial pressure matrix in the third scenario using the relational formula. Oxygen partial pressure matrix in the fourth scenario

[0072] (6) Based on the oxygen partial pressure matrix of the third scenario obtained in step (5) Oxygen partial pressure matrix in the fourth scenario Using the molecular weight W of the heterogeneous gas fg The molecular weight W of air air The calculated film cooling efficiency is as follows:

[0073]

[0074] Where η represents the surface air film cooling efficiency.

[0075] Example 3

[0076] In this embodiment, as Figure 4 As shown, a film cooling efficiency measurement system based on parallel line light source scanning includes: a calibration module, an image acquisition module, an image processing module, and an efficiency calculation module.

[0077] The calibration module calibrates the relationship between the light intensity and oxygen partial pressure of the pressure-sensitive paint after excitation. The image acquisition module sprays the pressure-sensitive paint onto the surface of the model to be measured and constructs four specific scenarios. In three of these scenarios, a parallel line light source is used to scan the surface of the model to be measured, and a scientific camera 6 is used to capture images, resulting in a series of images. The four specific scenarios are: Scenario 1: Excitation light 4 is off, there is no gas flow, corresponding to a dark environment; Scenario 2: Excitation light 4 is irradiated, there is no gas flow, corresponding to the reference conditions; Scenario 3: Excitation light 4 is irradiated, with the main stream 5 and jet 8 set to air; Scenario 4: Excitation light 4 is irradiated, with the main stream 5 set to air and jet 8 set to an oxygen-free heterogeneous gas. The image processing module processes the series of images to obtain the light intensity values ​​of the fluorescence emitted by the pressure-sensitive paint under the four scenarios. The efficiency calculation module calculates the surface gas film cooling efficiency of the model to be measured based on the light intensity values ​​and the relationship.

[0078] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for measuring the efficiency of film cooling based on parallel line light source scanning, characterized in that, Includes the following steps: The relationship between the light intensity and oxygen partial pressure of the pressure-sensitive paint after excitation was obtained by calibration. Pressure-sensitive paint was sprayed onto the surface of the model to be measured, and four specific scenarios were constructed. In three of these scenarios, a parallel line light source was used to scan the surface of the model, and images were taken using a scientific camera to obtain a series of images. The four specific scenarios included: Scenario 1: Excitation light off, no gas flow, corresponding to a dark environment; Scenario 2: Excitation light on, no gas flow, corresponding to reference conditions; Scenario 3: Excitation light on, with the main stream and jet set to air; Scenario 4: Excitation light on, with the main stream set to air and the jet set to an oxygen-free heterogeneous gas. The series of images were processed to obtain the light intensity values ​​of the fluorescence emitted by the pressure-sensitive paint under four different scenarios; Based on the light intensity value and the relationship, the surface air film cooling efficiency of the model to be measured is calculated. In the second, third, and fourth scenarios, the parallel line light source is used to scan the surface of the model to be measured. The parallel line light source scans along the surface, and a scientific camera is used to take pictures during the scanning process to obtain a series of images. The method for processing the series of images includes: Record the light intensity of the fluorescent region in each image in the series of images; The light intensity results of the series of images are stitched together, the positions of the light intensity results are repeatedly recorded, and the average value of the light intensity results is taken to obtain the light intensity value; The method for calculating the surface film cooling efficiency includes: The light intensity matrix captured in the first scene is taken as the light intensity value I1 in the dark environment, and the light intensity matrix captured in the second scene is taken as the light intensity value I under the reference condition. ref The light intensity matrix captured in the third scene is used as the light intensity value I3 in the third calibration process, the light intensity matrix captured in the fourth scene is used as the light intensity value I4 in the fourth calibration process, and the oxygen partial pressure matrix set under the reference conditions is used as the oxygen partial pressure value. Solve the oxygen partial pressure matrix in the third scenario using the aforementioned relationship. The oxygen partial pressure matrix in the fourth scenario Obtain the molecular weight W of the heterogeneous gas fg and the molecular weight W of the air air Based on the oxygen partial pressure matrix in the third scenario and the oxygen partial pressure matrix in the fourth scenario Calculate the surface film cooling efficiency: Where η represents the surface air film cooling efficiency.

2. The method for measuring film cooling efficiency based on parallel line light source scanning according to claim 1, characterized in that, The methods for obtaining the relation include: Inside a sealed cavity, the pressure-sensitive paint is irradiated with excitation light while the oxygen partial pressure inside the cavity is continuously changed. The light intensity and oxygen partial pressure values ​​are recorded to obtain the following relationship: Among them, I ref This represents the light intensity value under reference conditions. T represents the partial pressure of oxygen under reference conditions. ref I represents the temperature value under reference conditions, I1 represents the light intensity value in a dark environment, x represents the conditions at a certain moment during the calibration process, and I x This indicates the light intensity value during the calibration process. The value represents the oxygen partial pressure during the calibration process, and f represents the functional relationship between the light intensity, partial pressure, and temperature.

3. A gas film cooling efficiency measurement system based on parallel line light source scanning, wherein the measurement system applies the measurement method according to any one of claims 1-2, characterized in that, include: The system includes a calibration module, an image acquisition module, an image processing module, and an efficiency calculation module. The calibration module obtains the relationship between the light intensity and oxygen partial pressure of the pressure-sensitive paint after it is excited by calibration. The image acquisition module sprays the pressure-sensitive paint onto the surface of the model to be measured and constructs four specific scenarios. In three of these scenarios, a parallel line light source is used to scan the surface of the model to be measured, and a scientific camera is used to capture images, resulting in a series of images. The four specific scenarios include: Scenario 1: Excitation light off, no gas flow, corresponding to a dark environment; Scenario 2: Excitation light irradiated, no gas flow, corresponding to reference conditions; Scenario 3: Excitation light irradiated, with the main stream and jet being air; Scenario 4: Excitation light irradiated, with the main stream being air and the jet being an oxygen-free heterogeneous gas. The image processing module is used to process the series of images to obtain the light intensity values ​​of the fluorescence emitted by the pressure-sensitive paint under four scenarios; The efficiency calculation module calculates the surface air film cooling efficiency of the model to be measured based on the light intensity value and the relationship.

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