A dynamic pressure-sensitive paint calibration device and calibration method based on sinusoidal pressure

Abstract

A dynamic pressure-sensitive paint calibration device and calibration method based on sinusoidal pressure, which are disclosed by the present invention, belong to the technical field of calibration tests. The present invention includes an air inlet, a spray nozzle, a porous turntable, a pre-pressure hole, a reset device, a variable-diameter piston, a piston cylinder, a sealing cover plate, a glass window, an end cover, a laser vibrometer, a pressure-sensitive paint sample, a transmission belt, a glass window, a pressure-sensitive paint light source, and a photomultiplier tube. A pressure-sensitive paint light source and a photomultiplier tube are installed at the glass window on the side wall of the variable-diameter piston cylinder. The reset device is installed on the right side inside the variable-diameter piston cylinder. The present invention drives the turntable to cut the high-speed jet through a motor, the jet impacts the variable-diameter piston, and squeezes the sealed pressure chamber to generate pressure. Due to the periodic cutting action on the high-speed jet, through the extrusion of the piston, the pressure chamber generates a pulsating pressure with sinusoidal periodic changes, and the dynamic pressure-sensitive paint calibration is realized through the pulsating pressure. The present invention has the advantages of an adjustable pressure cavity, adjustable pressure average value and peak-to-peak value, and traceability.

Description

Technical Field

[0001] The present invention relates to a dynamic pressure-sensitive paint calibration device and calibration method based on sinusoidal pressure, and particularly to a sinusoidal pressure calibration device with a large pressure chamber and adjustable pressure, belonging to the technical field of calibration tests. Background Art

[0002] The pressure-sensitive paint technology is a relatively new aerodynamic test technology, mainly used for measuring the surface pressure of models in wind tunnel tests. As a pressure field parameter measurement technology, it is widely used because it can provide richer and more effective test data, and it is a replacement technology that can replace conventional pressure measurement test technologies. Currently, the dynamic performance calibration of pressure-sensitive paint basically uses a shock tube calibration device to calibrate the dynamic response characteristics. The shock tube generates a very fast step pressure acting on the pressure-sensitive paint, and the response time characteristics of the pressure-sensitive paint can be measured. However, general dynamic pressure calibration also includes the amplitude-frequency characteristics and phase difference under sinusoidal pressures of different frequencies, and the above parameters cannot be measured by the shock tube. Therefore, in order to obtain the amplitude waveform following characteristics of the pressure-sensitive paint at different frequencies, dynamic calibration based on sinusoidal pressure needs to be carried out. As a pressure field measurement means, due to process and function limitations, the geometric size of the pressure-sensitive surface of the pressure-sensitive paint is usually large, while the current sinusoidal pressure calibration device usually has a small pressure chamber to ensure the pressure waveform and peak-to-peak value, which cannot meet the calibration requirements of the pressure-sensitive paint. Summary of the Invention

[0003] Aiming at the requirements of large pressure cavity and small pulsation value in the calibration of pressure-sensitive paint, the main purpose of the present invention is to provide a dynamic pressure-sensitive paint calibration device and calibration method based on sinusoidal pressure. The motor drives the turntable to cut the high-speed jet, and the jet impacts the variable-diameter piston, squeezing the sealed pressure chamber to generate pressure. Due to the periodic cutting action on the high-speed jet, through the extrusion of the piston, the pressure chamber generates a sinusoidal periodic pulsating pressure, and the dynamic pressure-sensitive paint calibration is realized through the pulsating pressure. The present invention has the advantages of a large pressure cavity, adjustable average pressure and peak-to-peak value, and traceability.

[0004] The purpose of the present invention is achieved by the following technical solutions:

[0005] A dynamic pressure-sensitive paint calibration device based on sinusoidal pressure disclosed by the present invention includes an air inlet, a nozzle, a porous turntable, a pre-pressure hole, a reset device, a variable-diameter piston, a piston cylinder, a sealing cover plate, a glass window, an end cover, a laser vibrometer, a pressure-sensitive paint sample, a transmission belt, a glass window, a pressure-sensitive paint light source, a photomultiplier tube, a pressure chamber and a pre-pressure chamber.

[0006] An electric motor and a transmission device are used to drive a porous turntable. By cutting a high-pressure and high-speed jet, a periodic impact force is generated on a variable-diameter piston, and then a sinusoidally varying pressure is generated in a sealed pressure chamber. The main body of the device is a variable-diameter piston cylinder. The left side of the piston cylinder is a sealed pressure chamber. There is an installation hole on the side wall of the pressure chamber for installing a piezoresistive paint sample. At the same time, there is a glass window on the left side of the cylinder block, and there are glass windows on the side wall of the cylinder block. The glass windows are clamped and fixed by an end cover and a sealing cover plate. The right side of the piston cylinder is a cavity, in which a reset device for piston reset is installed. There is a pre-pressure hole on the right side of the cavity. The piston cylinder on the right side of the pressure chamber is in contact with the left side of the porous turntable. The right side of the turntable is in contact with the nozzle. The inside of the nozzle is a variable cross-section structure for increasing the air flow velocity. The right side of the nozzle is connected to an air inlet. The turntable is connected to the electric motor by a transmission belt. A laser vibrometer is installed on the left side of the variable-diameter piston cylinder. A piezoresistive paint light source and a photomultiplier tube are installed at the glass window on the side wall of the variable-diameter piston cylinder.

[0007] A piezoresistive paint light source and a photomultiplier tube are installed at the glass window on the side wall of the variable-diameter piston cylinder. The piezoresistive paint light source is used to excite the piezoresistive paint, and the photomultiplier tube is used to receive the fluorescence signal of the piezoresistive paint.

[0008] Preferably, the reset device is a spring coil installed on the right side inside the variable-diameter piston cylinder or an electromagnetic coil. When an electromagnetic coil is used, the problems of insufficient spring life and system vibration mode can be solved.

[0009] More preferably, the spring coil and the variable-diameter piston form a second-order damping oscillation system. By adjusting the elastic coefficient of the spring coil and the mass of the variable-diameter piston, the natural frequency of the damping system is made consistent with the upper limit of the calibration frequency of the device, and the pressure generated by the jet at high frequencies is increased by using the system resonance, that is, the problem of the small pressure generated by the jet at high frequencies is solved.

[0010] Preferably, a pre-pressure hole is opened on the right side inside the variable-diameter piston cylinder. The right side of the piston cylinder is pre-pressurized by inflating through the pre-pressure hole, which is used to adjust the initial position of the variable-diameter piston and the initial pressure of the pressure chamber, and prevent the sinusoidal pressure waveform in the pressure chamber from being incomplete due to too high or too low supply air pressure.

[0011] Preferably, a laser vibrometer is installed on the left side of the variable-diameter piston cylinder, and the real-time displacement of the internal piston can be monitored through the glass window on the left side.

[0012] Preferably, the right side of the variable-diameter piston cylinder is in contact with but not connected to the porous turntable. The electric motor is connected and drives the porous turntable to rotate through a transmission belt. There are round holes on the turntable for cutting the air flow.

[0013] Preferably, the inside of the nozzle is a variable-diameter structure. By changing the inner diameter size and shape, the jet velocity is increased, and its outlet is square, and the side length of the square is the same as the diameter of the round hole on the porous turntable.

[0014] A dynamic pressure-sensitive paint calibration method based on sinusoidal pressure is disclosed in the present invention and is implemented based on the dynamic pressure-sensitive paint calibration device based on sinusoidal pressure. The implementation method of the dynamic pressure-sensitive paint calibration method based on sinusoidal pressure is as follows:

[0015] Before calibration, select an appropriate spring coil and piston according to the upper limit of the calibration frequency, so that the natural vibration frequency of the second-order oscillation system composed of the spring coil and the piston is close to the upper limit of the calibration frequency. To ensure that the sinusoidal pressure waveform is not distorted, the porous wheel disc should ensure uniform hole opening, and the arc length connecting the centers of two adjacent holes is approximately twice the hole diameter.

[0016] Adopt the method of using a motor to drive a turntable to cut a high-speed jet to generate a periodic pulsating air flow as the pressure source. At the same time, adopt a variable-diameter piston structure to convert the high-frequency pulsating pressure generated by the high-speed and high-pressure air flow into a large-volume and low-pulsation value pressure field suitable for pressure-sensitive paint calibration.

[0017] Air enters and exits through the pre-pressure hole to adjust the initial pressure of the pre-pressure chamber, thereby changing the initial value of the pulsating pressure in the pressure chamber. This initial value is the average value of the pulsating pressure. By adjusting the diameter and contraction ratio of the incoming flow nozzle, the incoming flow pressure and velocity are changed to generate pulsating pressure values suitable for different working conditions.

[0018] Use a laser vibrometer to record the displacement ΔL of the variable-diameter piston. According to the gas state equation, for a closed pressure chamber, PV = constant. Therefore, the pressure in the pressure chamber is calculated according to the displacement of the variable-diameter piston.

[0019] The test working conditions of the dynamic pressure-sensitive paint calibration device include parameters: calibration frequency, average value of sinusoidal pressure, and pulsation value.

[0020] Frequency: According to the calibration requirements, by controlling the motor speed, the air flow impact frequency is changed, and then the pressure change frequency is changed.

[0021] Average pressure: Connect a pressure controller through the pre-pressure hole of the device. By adjusting the pressure in the pre-pressure chamber, the initial pressure P0 is changed, which is the average pressure value for calibration.

[0022] Pulsation value: The pulsation value of the pressure is mainly driven by the gas source. Therefore, the peak-to-peak value of the pulsating pressure can be adjusted by adjusting the gas source pressure and the diameter of the air inlet.

[0023] Since the gas state equation is PV = γRT, when the ambient temperature remains unchanged, the pressure in the pressure chamber is inversely proportional to the pressure volume, that is: P0V0 = P t V t .

[0024] The initial volume of the pressure chamber is:

[0025]

[0026] The real-time pressure calculation formula in the pressure chamber is as follows:

[0027]

[0028] Where:

[0029] ΔL - piston displacement;

[0030] P t - real-time pressure in the pressure chamber;

[0031] P₀ - initial pressure of the pressure chamber;

[0032] L₀ - initial distance of the piston;

[0033] D - piston diameter.

[0034] Turn on the light source of the pressure-sensitive paint and the photomultiplier tube, collect the light intensity signal of the pressure-sensitive paint, and then obtain the measurement result of the pressure-sensitive paint; according to the piston movement displacement data ΔL = f(t) recorded by the laser vibrometer, calculate the change of the pressure in the pressure chamber over time, and compare to obtain the dynamic characteristics of the pressure-sensitive paint, realizing the calibration of the dynamic pressure-sensitive paint.

[0035] Beneficial effects:

[0036] 1. A dynamic pressure-sensitive paint calibration device and calibration method based on sinusoidal pressure disclosed by the present invention drive a turntable to cut a high-speed jet through a motor. The jet impacts a variable-diameter piston, squeezing the sealed pressure chamber to generate pressure. Due to the periodic cutting action on the high-speed jet, through the extrusion of the piston, the pressure chamber generates a pulsating pressure with sinusoidal periodic changes, and the amplitude following characteristic calibration of the dynamic pressure-sensitive paint is realized through the pulsating pressure, that is, the calibration of the dynamic pressure-sensitive paint is realized.

[0037] 2. A dynamic pressure-sensitive paint calibration device and calibration method based on sinusoidal pressure disclosed by the present invention generate sinusoidal pressure by the way of air flow directly impacting the piston, can adjust the air supply flow rate and speed according to requirements to generate sinusoidal pressures with different amplitudes, and can achieve quantitative and precise adjustment according to the constructed relational expression.

[0038] 3. To solve the problem of the relatively small pressure chamber of the conventional import and export modulated sine pressure generator, a dynamic pressure-sensitive paint calibration device and calibration method based on sine pressure disclosed by the present invention adopt a piston structure to increase the sine pressure; and a pre-pressure hole is opened on the right side inside the variable-diameter piston cylinder, and the right side of the piston cylinder is pre-pressurized by inflating through the pre-pressure hole, which is used to adjust the initial position of the variable-diameter piston and the initial pressure of the pressure chamber to prevent the sine pressure waveform in the pressure chamber from being incomplete; in addition, the spring coil and the variable-diameter piston form a second-order damping oscillation system, and by adjusting the elastic coefficient of the spring coil and the mass of the variable-diameter piston, the natural frequency of the damping system is made consistent with the upper limit of the calibration frequency of the device, and the resonance of the system is used to increase the pressure generated by the jet at high frequencies.

[0039] 4. A dynamic pressure-sensitive paint calibration device and calibration method based on sine pressure disclosed by the present invention realize the absolute calibration of dynamic pressure by monitoring the piston position to obtain the pressure change in the pressure chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is the front view of a dynamic pressure-sensitive paint calibration device based on sine pressure disclosed by the present invention.

[0041] Figure 2 It is the top view of a dynamic pressure-sensitive paint calibration device based on sine pressure disclosed by the present invention.

[0042] Wherein, 1 - air inlet, 2 - nozzle, 3 - porous turntable, 4 - pre-pressure hole, 5 - spring coil, 6 - variable-diameter piston, 7 - piston cylinder, 8 - sealing cover plate, 9 - glass window, 10 - end cover, 11 - laser vibrometer, 12 - pressure-sensitive paint sample, 13 - transmission belt, 14 - glass window, 15 - pressure-sensitive paint light source, 16 - photomultiplier tube, 17 - pressure chamber, 18 - pre-pressure chamber.

[0043] Figure 3 It is the main structure diagram of the pressure chamber. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The technical solutions of the present invention will be further specifically described below through examples in combination with the drawings. At the same time, the technical problems solved by the technical solutions of the present invention and the beneficial effects are also described. It should be noted that the described embodiments are only for facilitating the understanding of the present invention and do not impose any limitation on it.

[0045] Such as Figure 1 、 2As shown in the figure, a dynamic pressure-sensitive paint calibration device based on sinusoidal pressure disclosed in this embodiment includes an air inlet 1, a nozzle 2, a porous turntable 3, a pre-pressure hole 4, a spring coil 5, a variable-diameter piston 6, a piston cylinder 7, a sealing cover plate 8, a glass window 9, an end cover 10, a laser vibrometer 11, a pressure-sensitive paint sample 12, a transmission belt 13, a glass window 14, a pressure-sensitive paint light source 15, a photomultiplier tube 16, a pressure chamber 17, and a pre-pressure chamber 18.

[0046] A motor and a transmission device are used to drive the porous turntable 3. By cutting the high-pressure and high-speed jet flow, a periodic impact force is generated on the variable-diameter piston 6, and then a sinusoidally varying pressure is generated in the sealed pressure chamber. The main body of the device is a variable-diameter piston cylinder 7. The left side of the piston cylinder 7 is a sealed pressure chamber. There is an installation hole on the side wall of the pressure chamber for installing the pressure-sensitive paint sample 12. At the same time, there is a glass window 9 on the left side of the cylinder body, and a glass window 14 is opened on the side wall of the cylinder body. The glass window is clamped and fixed by the end cover 10 and the sealing cover plate 8. The right side of the piston cylinder is a cavity, in which a spring coil 5 for piston reset is installed. There is a pre-pressure hole on the right side of the cavity. The initial pressure of the pre-pressure chamber 18 can be adjusted through the pre-pressure hole. The piston cylinder on the right side of the pressure chamber 17 is in contact with the left side of the porous turntable 3. The right side of the turntable is in contact with the nozzle 2. The inside of the nozzle has a variable cross-section structure for increasing the air flow velocity. The right side of the nozzle is connected to the air inlet 1. The turntable is connected to the motor through the transmission belt 13. A laser vibrometer 11 is installed on the left side of the variable-diameter piston cylinder. A pressure-sensitive paint light source 15 and a photomultiplier tube 16 are installed at the glass window on the side wall of the variable-diameter piston cylinder.

[0047] A dynamic pressure-sensitive paint calibration method based on sinusoidal pressure disclosed in this embodiment is realized based on the above-mentioned dynamic pressure-sensitive paint calibration device based on sinusoidal pressure. The realization method of the dynamic pressure-sensitive paint calibration method based on sinusoidal pressure is as follows:

[0048] Before calibration, select appropriate spring coil 5 and variable-diameter piston 7 according to the upper limit of the calibration frequency, and make the natural vibration frequency of the second-order oscillation system composed of the spring coil and the variable-diameter piston close to the upper limit of the calibration frequency. To ensure that the sinusoidal pressure waveform is not distorted, the porous turntable 3 should ensure uniform hole opening, and the arc length connecting the centers of two adjacent holes is approximately 2 times the hole diameter.

[0049] Install the pressure-sensitive paint sample 12 and seal the pressure chamber. Fill the appropriate gas through the pre-pressure hole according to the range of the pressure-sensitive paint to be measured, so that the initial pressure in the pressure chamber reaches the predetermined pressure P0. Use the laser vibrometer 11 to record the initial position of the variable-diameter piston 7 at this time, and set it as the zero point. At this time, the diameter of the pressure chamber is the same as the piston diameter D, and the length is L0.

[0050] Adjust the intake pressure P1 so that the air flow impacts the variable-diameter piston 7 through the porous rotating disk 3. The piston is displaced to the right under the impact of the high-speed and high-pressure air flow. At this time, turn on the motor to make the porous rotating disk 3 rotate. The round holes on the porous rotating disk cut the square holes of the nozzle 2, causing the impact effect of the air flow to produce a sinusoidal periodic change. At this time, the piston system vibrates under forced vibration under the impact of the air flow. The piston moves reciprocally under the action of the impact and the pressure in the pressure chambers on both sides, forming a sinusoidal pressure, and the frequency is determined by the rotation speed of the rotating disk.

[0051] According to the gas state equation PV = γRT, it can be known that when the ambient temperature remains unchanged, the pressure in the pressure chamber is inversely proportional to the pressure volume, that is: P0V0 = P t V t 。

[0052] The initial volume of the pressure chamber is:

[0053]

[0054] Then the calculation formula for the real-time pressure in the pressure chamber is:

[0055]

[0056] Among them:

[0057] ΔL - piston displacement;

[0058] P t The real-time pressure in a pressure chamber;

[0059] P0 - initial pressure of the pressure chamber;

[0060] L0 - initial distance of the piston;

[0061] D - piston diameter.

[0062] During the experiment, turn on the light source of the pressure-sensitive paint and the photomultiplier tube, collect the light intensity signal of the pressure-sensitive paint, and then obtain the measurement result of the pressure-sensitive paint; according to the piston movement displacement data ΔL = f(t) recorded by the laser vibrometer, calculate the change of the pressure in the pressure chamber over time, and compare to obtain the dynamic characteristics of the pressure-sensitive paint to achieve the calibration of the dynamic pressure-sensitive paint.

[0063] The above specific description further details the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dynamic pressure-sensitive paint calibration device based on sinusoidal pressure, characterized in that: It includes an air inlet, a nozzle, a porous rotary disk, a preloading hole, a reset device, a variable-diameter piston, a variable-diameter piston cylinder, a sealing cover plate, a glass window 1, an end cover, a laser vibrometer, a pressure-sensitive paint sample, a transmission belt, a glass window 2, a pressure-sensitive paint light source, a photomultiplier tube, a pressure chamber and a preloading chamber; the main body of the dynamic pressure-sensitive paint calibration device is the variable-diameter piston cylinder, the left side of the variable-diameter piston cylinder is a sealed pressure chamber, and a variable-diameter piston is arranged inside the variable-diameter piston cylinder; a motor plus a transmission belt is used to drive the porous rotary disk, and by cutting the high-pressure and high-speed jet, a periodic impact force is generated on the variable-diameter piston, and then a sinusoidally varying pressure is generated in the sealed pressure chamber; an installation hole is opened on the side wall of the pressure chamber for installing the pressure-sensitive paint sample, at the same time, a glass window 1 is opened on the left end face of the variable-diameter piston cylinder, and a glass window 2 is opened on the side wall of the variable-diameter piston cylinder, and the glass window 1 and the glass window 2 are clamped and fixed by the end cover and the sealing cover plate; the right side of the variable-diameter piston cylinder is a preloading chamber, and a reset device for resetting the variable-diameter piston is installed in the preloading chamber, and a preloading hole is opened on the right side of the preloading chamber; the right side of the pressure chamber, the variable-diameter piston cylinder is in contact with the left side of the porous rotary disk; the right side of the porous rotary disk is in contact with the nozzle, the inside of the nozzle is a variable cross-section structure for increasing the air flow velocity, the right side of the nozzle is connected to the air inlet, and the porous rotary disk is connected to the motor through the transmission belt; a laser vibrometer is installed on the left side of the variable-diameter piston cylinder; a pressure-sensitive paint light source and a photomultiplier tube are installed at the glass window 2 on the side wall of the variable-diameter piston cylinder; The pressure-sensitive paint light source is used to excite the pressure-sensitive paint, and the photomultiplier tube is used to receive the fluorescence signal of the pressure-sensitive paint.

2. The dynamic pressure-sensitive paint calibration device based on sine pressure according to claim 1, wherein: The reset device is a spring coil installed on the right side inside the variable-diameter piston cylinder.

3. The dynamic pressure-sensitive paint calibration device based on sinusoidal pressure according to claim 2, characterized in that: The spring coil and the variable-diameter piston form a second-order damping oscillation system. By adjusting the elastic coefficient of the spring coil and the mass of the variable-diameter piston, the natural frequency of the second-order damping oscillation system is made consistent with the upper limit of the calibration frequency of the dynamic pressure-sensitive paint calibration device, and the resonance of the second-order damping oscillation system is used to increase the pressure generated by the high-pressure and high-speed jet at high frequencies.

4. A dynamic pressure-sensitive paint calibration device based on sinusoidal pressure according to claim 2 or 3, characterized in that: Inflate through the preloading hole to preload the right side of the variable-diameter piston cylinder, which is used to adjust the initial position of the variable-diameter piston and the initial pressure of the pressure chamber.

5. A dynamic pressure-sensitive paint calibration device based on sinusoidal pressure according to claim 2 or 3, characterized in that: A laser vibrometer is installed on the left side of the variable-diameter piston cylinder, and the real-time displacement of the internal piston can be monitored through the glass window 1 on the left side.

6. The dynamic pressure-sensitive paint calibration device based on sinusoidal pressure according to claim 2 or 3, characterized in that: The right side of the variable-diameter piston cylinder is in contact with the porous rotary disk but not connected. The motor is connected and drives the porous rotary disk to rotate through the transmission belt, and circular holes are opened on the porous rotary disk for cutting the air flow.

7. A dynamic pressure-sensitive paint calibration device based on sinusoidal pressure according to claim 2 or 3, characterized in that: The inside of the nozzle is a variable-diameter structure. By changing the inner diameter size and shape, the speed of the high-pressure and high-speed jet is increased, and the outlet of the nozzle is square, and the side length of the square is the same as the diameter of the circular hole on the porous rotary disk.

8. A dynamic pressure-sensitive paint calibration method based on sinusoidal pressure, based on a dynamic pressure-sensitive paint calibration device according to claim 2 or 3, characterized in that: Before calibration, select an appropriate spring coil and variable-diameter piston according to the upper limit of the calibration frequency, and make the natural vibration frequency of the second-order damping oscillation system composed of the spring coil and the variable-diameter piston close to the upper limit of the calibration frequency; to ensure that the sinusoidal pressure waveform is not distorted, the porous rotary disk should ensure uniform hole opening, and the arc length connecting the centers of two adjacent holes should be 2 times the hole diameter; A periodic pulsating air flow is generated as a pressure source by driving a porous turntable to cut a high-pressure and high-speed jet with a motor. At the same time, a variable-diameter piston structure is used to convert the high-frequency pulsating pressure generated by the high-pressure and high-speed jet into a large-volume and low-pulsation-value pressure field suitable for pressure-sensitive paint calibration. Air enters and exits through the pre-pressure holes to adjust the initial pressure of the pre-pressure chamber, thereby changing the initial value of the pulsating pressure in the pressure chamber. This initial value of the pulsating pressure is the average value of the pulsating pressure. By adjusting the diameter and contraction ratio of the incoming flow nozzle, the incoming flow pressure and velocity are changed to generate pulsating pressure values suitable for different working conditions. A laser vibrometer is used to record the displacement ΔL of the variable-diameter piston. According to the gas state equation, for a closed pressure chamber, PV = constant. Therefore, the pressure in the pressure chamber is calculated based on the displacement of the variable-diameter piston. The test working conditions of the dynamic pressure-sensitive paint calibration device include parameters: calibration frequency, average sine pressure value, and pulsation value. Calibration frequency: According to the calibration requirements, by controlling the motor speed, the air flow impact frequency is changed, and then the pressure change frequency is changed. Average sine pressure value: Through the pre-pressure holes of the dynamic pressure-sensitive paint calibration device, connect a pressure controller. By adjusting the pressure in the pre-pressure chamber, the initial pressure P0 is changed, which is the calibrated average pressure value. Pulsation value: The pulsation value of the pressure is driven by the air source. Therefore, by adjusting the air source pressure and the diameter of the air inlet, the peak-to-peak value of the pulsating pressure can be adjusted. Due to the ideal gas law PV = γRT, when the ambient temperature remains constant, the pressure in the pressure chamber is inversely proportional to the pressure volume, i.e.: P0V0 = P t V t ; The initial volume of the pressure chamber is: Then the formula for calculating the real-time pressure in the pressure chamber is: Where: V0 is the initial volume of the pressure chamber; V t is the real-time volume in the pressure chamber; ΔL - Displacement of the variable-diameter piston; P t — Real-time pressure in the pressure chamber; P0 - Initial pressure of the pressure chamber; L0 - Initial distance of the variable-diameter piston; D - Diameter of the variable-diameter piston; Turn on the pressure-sensitive paint light source and the photomultiplier tube to collect the pressure-sensitive paint light intensity signal, and then obtain the measurement result of the pressure-sensitive paint; according to the displacement ΔL = f(t) of the variable-diameter piston recorded by the laser vibrometer, by calculating the change of the pressure in the pressure chamber over time, the dynamic characteristics of the pressure-sensitive paint are compared to achieve the calibration of the dynamic pressure-sensitive paint.

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