Wireless ultrasonic measurement system and design method thereof

Abstract

The present invention relates to the technical field of temperature and load monitoring, discloses a wireless ultrasonic measurement system and a design method thereof, provides a wireless ultrasonic measurement method, a wireless ultrasonic measurement device based on the method, and an integrated preparation method of a composite film, a turbine blade, and a spiral sensor coil. The entire system includes an instrument end and a sensor end. The instrument end is composed of a host (monitoring system), a transmitting coil, a receiving coil, and a coil core. The sensor end is an integrated design of a turbine blade, a composite piezoelectric film on the end face of the turbine blade, and a spiral sensor coil. The transmitting coil is connected to a pulse generator to realize wireless transmission of electromagnetic wave pulse signals; the spiral sensor coil and the composite piezoelectric film form a loop as an antenna to wirelessly transmit and receive ultrasonic signals generated by the piezoelectric film; the receiving coil is connected to the host to realize wireless reception of pulse signals.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic measurement preparation, and in particular to a wireless ultrasonic measurement system and a design method thereof. Background Art

[0002] Traditional temperature measurement systems are all carried out through wired methods. This method has many limitations in many occasions such as humidity and high temperature, and is not suitable for aircraft engines. Therefore, it is necessary to develop a wireless acoustic transmission system. Wireless transmission technology is a type of technology that can achieve the transmission of acoustic waves to the load without physical connection. It usually uses electric fields, electromagnetic fields or acoustic fields as carriers to achieve spatial energy transfer. It is divided into three methods: electromagnetic radiation, electric field coupling and magnetic field coupling. Magnetic field coupling is the most studied of all wireless transmission technologies at present, and has been applied in electric vehicles, mobile communications, robots and household appliances. However, this wireless transmission technology based on magnetic field coupling has a limited transmission distance, and the transmission efficiency will drop sharply with the increase of transmission distance; in addition, in conductive media such as metals and seawater, the propagation of electromagnetic fields will be severely attenuated, so this method cannot be used for efficient transmission.

[0003] Traditional ultrasonic wireless measurement uses an excitation coil, a receiving coil, and a ceramic coil to achieve wireless transmission and reception of ultrasound. The ultrasonic frequency reaches 5MHz, but the ceramic coil is large in size (>65mm), which is larger than the width of an aircraft engine turbine blade.

[0004] The microwave resonance echo frequency shift (MASER) technology connects the sensor elements used to monitor temperature, stress, etc. in parallel to the resonant network, converts the changes in physical parameters into changes in capacitance or inductance, thereby changing the equivalent resonance frequency of the resonant network accordingly, and then affecting the transition path of polaritons. By measuring the frequency shift of the microwave resonance echo, the parameter changes of the sensor element can be measured, and then the physical quantity can be obtained through the calibration relationship. It has the advantage of long measurement distance (~100m), but the response frequency is low, and it is not suitable for occasions such as ultrasonic measurement that require high sampling frequency.

[0005] Therefore, it is necessary to develop new wireless ultrasonic measurement technology to solve current problems. Summary of the invention

[0006] In order to address the shortcomings of the prior art, the present invention provides a wireless ultrasonic measurement system and a design method thereof, which can realize wireless ultrasonic transmission and reception and are used to monitor the load and temperature of high-speed rotating aircraft engine turbine blades. The whole system includes an instrument end and a sensor end. The instrument end is composed of a host (monitoring system), a transmitting coil, a receiving coil, a coil core, and a pulse generator. The sensor end is an integrated design of a turbine blade, a composite piezoelectric film on the end face of the turbine blade, and a spiral sensor coil.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] In the first aspect, the present invention provides a method for designing a wireless ultrasonic measurement system (turbine blades, composite piezoelectric film sensors, and spiral sensor coils are integrated), characterized in that: the system is applied to high-speed rotating aircraft engine turbine blades to realize wireless ultrasonic transmission and reception, and to monitor the load and temperature of the object to be measured; the system comprises an instrument end and a sensor end, the instrument end is composed of a host, i.e., a monitoring system, a transmitting coil, a receiving coil, a coil core, and a pulse generator, and the sensor end is a turbine blade, a composite piezoelectric film on the end face of the turbine blade, and a spiral sensor coil are integrated and designed and prepared; the integrated preparation method of the turbine blade, the composite piezoelectric film, and the spiral sensor coil comprises the following steps:

[0009] S1: Deposition of bottom metal electrode on the surface of turbine blade;

[0010] S2: depositing piezoelectric coating;

[0011] S3: Simultaneous deposition of the top spiral sensing coil and the top metal electrode;

[0012] S4: Deposition of a protective layer.

[0013] As a preferred solution, the bottom metal electrode, piezoelectric coating, spiral sensor coil, top metal electrode and protective layer are all prepared by radio frequency magnetron sputtering technology;

[0014] The composite piezoelectric film includes a piezoelectric coating, a bottom metal electrode, a top metal electrode, and a protective layer. The middle layer is a piezoelectric coating, and the piezoelectric coating is located between the bottom electrode and the top electrode. The other ends of the bottom electrode and the top electrode are respectively connected to the two ends of the spiral sensing coil, so that the piezoelectric coating and the two electrode layers form a capacitor. Under the action of an alternating magnetic field, the electromagnetic signal received by the spiral sensing coil is converted into an induced voltage to provide an electrical signal to the piezoelectric layer.

[0015] The top electrode, the piezoelectric layer, the bottom electrode and the spiral sensing coil form a closed circuit. The spiral sensing coil is used to receive the electromagnetic power from the transmitting coil and generate a sufficiently high voltage for the piezoelectric layer; and convert the converted electrical signal back into an electromagnetic wave.

[0016] The bottom metal electrode can be Ag, Cr, Mo, chromium-nickel-iron alloy, etc., with a thickness of about 0.5-5 microns; deposition parameters: using corresponding pure target material, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250°C, deposition time between 0.5h-2h, and the distance between the target material and the substrate between 5cm-10cm.

[0017] The piezoelectric coating can be other piezoelectric materials such as AlN, AlScN, LiNbO3, LiTaO3, ZnO, PZT, etc., and will also serve as a protective layer for the bottom metal electrode, with a thickness of about 8-25 microns; deposition parameters: using corresponding pure target materials, RF power between 700-1500W, deposition pressure between 0.5-4Pa, Ar / N2 between 1 / 2-5 / 1 or Ar / O2 between 1 / 2-5 / 1 (nitrides use Ar and N2, oxides use Ar and O2), chamber temperature between 100-250°C, deposition time between 2h-10h, and the distance between the target and the substrate between 2cm-7cm.

[0018] The spiral sensing coil can be made of Ag, Cr, Mo, chromium-nickel-iron alloy, etc., with a thickness of about 1-10 microns. One end of the spiral electrode will be connected to the bottom electrode, and the other end will be connected to the top electrode (the square area in the center of the piezoelectric layer); deposition parameters: using corresponding pure target materials, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250°C, deposition time between 1h-4h, and the distance between the target material and the substrate between 3cm-7cm.

[0019] The top metal electrode can be Ag, Cr, Mo, chromium-nickel-inconel alloy, etc., with a thickness of about 10-30 microns. Deposition parameters: using corresponding pure target materials, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250°C, deposition time between 2h-12h, and the distance between the target and the substrate between 3cm-7cm.

[0020] The protective layer can be AlN, AlCrO, Al2O3, SiO2, used to encapsulate and protect sensors, coils and top electrodes, with a thickness of about 20-40 microns. Deposition parameters: using corresponding pure target materials, RF power between 700-1000W, deposition pressure between 0.5-4Pa, Ar / N2 between 1 / 2-5 / 1 or Ar / O2 between 1 / 2-5 / 1 (nitrides use Ar and N2, oxides use Ar and O2), chamber temperature between 100-250°C, deposition time between 5h-20h, and the distance between the target and the substrate between 2cm-7cm.

[0021] In the second aspect, the present invention also provides a wireless ultrasonic measurement system based on the method, including an instrument end and a sensor end. The instrument end is composed of a host (monitoring system), a transmitting coil, a receiving coil, a coil core, and a pulse generator. The sensor end is an integrated design of a turbine blade, a composite piezoelectric film on the end face of a turbine blade, and a spiral sensor coil.

[0022] The transmitting coil is connected to the pulse generator, and the wireless transmission of the electromagnetic wave pulse signal (alternating magnetic field) is realized by adjusting the pulse electrical signal of the pulse generator;

[0023] The composite piezoelectric film includes a bottom metal electrode, a piezoelectric coating, a top metal electrode, and a protective layer. The middle layer is the piezoelectric coating, which is located between the bottom electrode and the top electrode. The other ends of the bottom electrode and the top electrode are respectively connected to the two ends of the spiral sensing coil, so that the piezoelectric coating and the two electrode layers form a capacitor.

[0024] The spiral sensor coil and the composite piezoelectric film form a loop and serve as an antenna with three functions: ① Based on electromagnetic induction and infinite coupling, the spiral sensor coil converts the alternating magnetic field into an electrical signal; ② Based on the inverse piezoelectric effect, the composite piezoelectric film converts the induced voltage into an ultrasonic transmission wave; ③ Wirelessly transmits and receives the ultrasonic signal generated by the piezoelectric film and the ultrasonic reflected wave reflected back after being transmitted through the turbine blades, and converts the ultrasonic reflected wave back into an electrical signal, which is then converted into an electromagnetic wave by the spiral sensor coil.

[0025] The receiving coil is connected to the host to realize wireless reception of the converted electromagnetic signal.

[0026] The coil core is a high-frequency ferrite core or a ferrite coil core, which is used to increase the inductance of the coil and improve the conversion efficiency of electromagnetic energy to electrical energy.

[0027] The radio-transparent ceramic glass window is used to introduce electromagnetic signals from the transmitting coil into the turbine blade.

[0028] In a third aspect, the present invention provides a wireless ultrasonic measurement method, characterized in that: using the wireless ultrasonic measurement system as described above, the method comprises the following steps:

[0029] 1) The transmitting coil is connected to the pulse generator to realize the wireless transmission of the electromagnetic wave pulse signal, and the alternating magnetic field is obtained by adjusting the pulse output voltage of the pulse generator (the main idea of ​​wireless coupling is based on Faraday's law of electromagnetic induction. Usually, the magnetic flux changes by adjusting the iron core to move up and down perpendicular to the coil, and an induced current is generated in the spiral sensor coil. If there is a capacitor in the spiral sensor coil circuit, an induced voltage will be generated at both ends of the capacitor. However, the present invention does not need to adjust the position of the iron core. By connecting the transmitting coil to the pulse generator, it only needs to adjust the output voltage of the pulse generator, which can also change the magnetic flux and obtain fluctuating alternating electromagnetic wave pulses. Compared with moving the position of the iron core to change the magnetic flux, the voltage regulation method of the present invention is more controllable, and has higher operability and repeatability);

[0030] 2) The spiral sensing coil converts the received fluctuating electromagnetic waves (i.e., alternating magnetic fields) into electrical signals (i.e., induced voltage);

[0031] 3) The composite piezoelectric film sensor converts electrical signals into ultrasonic transmission waves based on the inverse piezoelectric effect;

[0032] 4) The ultrasonic transmission wave is transmitted in the turbine blade and reflected back, which is called the ultrasonic reflection wave;

[0033] 5) The composite piezoelectric film sensor converts ultrasonic reflected waves back into electrical signals based on the piezoelectric effect;

[0034] 6) The electrical signal will be converted into electromagnetic waves by the spiral sensing coil and received by the receiving coil;

[0035] 7) The signal from the receiving coil will be further processed by the controller and displayed on the computer terminal using Lab View software.

[0036] Due to thermal expansion and stress stretching, the flight time, pulse amplitude and pulse frequency of ultrasonic waves in turbine blades will be affected by temperature and load, causing signal attenuation, acoustic time delay and frequency drift in ultrasonic reflected waves. Therefore, temperature and load prediction and monitoring can be carried out by measuring the shape of the echo.

[0037] The advantages and beneficial effects of the present invention are as follows:

[0038] 1. The measuring system of the present invention is mainly based on Faraday's law of electromagnetic induction, belongs to wireless measurement, and is not limited by distance; there is no need to adjust the position of the iron core, only a pulse generator needs to be connected to the transmitting coil, and by adjusting the output voltage of the pulse generator to change the magnetic flux, the fluctuating electromagnetic wave alternating pulse can be obtained, and then converted into an electrical signal through the spiral sensor coil to provide voltage for the piezoelectric coating. Compared with moving the position of the iron core to change the magnetic flux, the voltage control method of the present invention is not affected by human subjective factors, has stronger controllability, and higher operability and repeatability.

[0039] 2. The present invention also provides a unique sensor end, which is an integration of turbine blades, composite film, and spiral sensor coil, and specifically includes a bottom metal electrode, a piezoelectric coating, a spiral sensor coil, a top metal electrode, and a protective layer; the top electrode, the piezoelectric layer, the bottom electrode, and the spiral sensor coil form a closed circuit, the spiral sensor coil is used to receive electromagnetic power from the transmitting coil, and the top electrode, the piezoelectric layer, and the bottom electrode form a capacitor, under the action of an alternating magnetic field, the spiral sensor coil receives the electromagnetic signal and converts it into an induced voltage, providing an electrical signal to the piezoelectric layer in the capacitor.

[0040] 3. The spiral sensor coil of the present invention is deposited by radio frequency magnetron sputtering, has a small size, is controllable and adjustable, and solves the problem of excessive size of ceramic coils in traditional wireless ultrasonic methods.

[0041] 4. The bottom metal electrode, piezoelectric coating, top metal electrode and protective layer of the present invention are also deposited based on radio frequency magnetron sputtering, and the size is easy to control.

[0042] 5. Compared with the traditional piezoelectric chips, the composite piezoelectric film prepared by the present invention is of micron level, smaller in size, does not require any coupling agent, is prepared by sputtering, has strong adhesion to the object to be measured, is not easy to deform or fall off at high temperature, and has a wide temperature measurement range.

[0043] 6. The sensor end of the present invention is based on the piezoelectric effect. It converts changes in temperature, load and other states into changes in piezoelectric signals, thereby realizing online measurement of temperature and stress. It can be measured by signal amplitude, frequency, acoustic time and other aspects. It has the characteristics of high precision and anti-interference. Compared with the microwave resonant echo frequency shift (MASER) technology, it has a wider applicable frequency range.

[0044] 7. The wireless load and temperature measurement system of the present invention is not only applicable to aerospace engine turbine blades, but also to other equipment, such as nuclear power bolts and other fasteners. It only needs to deposit the composite film and spiral sensor coil on the end face of the corresponding bolt to carry out online temperature and stress measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A schematic diagram of the wireless ultrasonic measurement method and device structure designed for the present invention;

[0046] Figure 2 The working principle diagram of the wireless ultrasonic measuring device designed for the present invention;

[0047] Figure 3 Equivalent circuit diagram of the sensor designed for the present invention;

[0048] Figure 4 This is a flow chart of the integrated preparation method of the composite film, turbine blades, and spiral sensor coils of the present invention;

[0049] Figure 5 It is a front view of the integrated composite film, turbine blades, and spiral sensor coil of the present invention;

[0050] Figure 6 It is a top view of the integrated composite film, turbine blades, and spiral sensor coil of the present invention.

[0051] In the figure: 1. Receiving coil, 2. Transmitting coil, 3. Coil core, 4. Pulse generator, 5. Monitoring system, 6. Transmitting electromagnetic waves, 7. Turbine casing, 8. Radio transparent ceramic glass window, 9. Receiving electromagnetic waves, 10. Spiral sensor coil, 11. Turbine blades, 12. Ultrasonic transmitting waves, 13. Ultrasonic reflected waves, 14. Piezoelectric coating, 15. Bottom electrode, 16. Top electrode, 17. Protective layer, 18. Turbine blade end face. DETAILED DESCRIPTION

[0052] For a better understanding of the present invention, the following embodiments are further explanations of the present invention, but the content of the present invention is not limited to the following embodiments. In the present invention, the single-layer piezoelectric film is uniformly expressed as a piezoelectric coating, and the composite piezoelectric film refers to the whole of the piezoelectric coating, the bottom metal electrode, the top metal electrode, and the protective layer.

[0053] Example 1

[0054] This embodiment provides a wireless ultrasonic measurement method, comprising the following steps:

[0055] 1) The transmitting coil is connected to the pulse generator to realize the wireless transmission of the electromagnetic wave pulse signal, and the alternating pulse magnetic field is obtained by adjusting the pulse output voltage of the pulse generator;

[0056] 2) The spiral sensing coil converts the received alternating magnetic field signal into an electrical signal;

[0057] 3) The composite piezoelectric film sensor converts electrical signals into ultrasonic transmission waves based on the inverse piezoelectric effect;

[0058] 4) The ultrasonic transmission wave is transmitted in the turbine blade and reflected back, which is called the ultrasonic reflection wave;

[0059] 5) The composite piezoelectric film sensor converts ultrasonic reflected waves back into electrical signals based on the piezoelectric effect;

[0060] 6) The electrical signal will be converted into electromagnetic waves by the spiral sensing coil and received by the receiving coil;

[0061] 7) The signal from the receiving coil will be further processed by the controller and displayed on the computer terminal using Lab View software.

[0062] Due to thermal expansion and stretching effects, the flight time, pulse amplitude and pulse frequency of ultrasonic waves in turbine blades will be affected by temperature and load, causing signal attenuation, acoustic time delay and frequency drift in ultrasonic reflected waves. Therefore, temperature and load prediction and monitoring can be performed by measuring the shape of the echo.

[0063] Example 2

[0064] This embodiment provides a wireless ultrasonic measurement system based on the method, such as Figure 1-Figure 6 , including the instrument end and the sensor end. The instrument end is composed of a host (monitoring system 5), a transmitting coil 2, a receiving coil 1, a coil core 3, and a pulse generator 4. The sensor end is composed of a turbine blade 11, a composite piezoelectric film on the end surface of the turbine blade ( Figure 5-Figure 6 ), the spiral sensor coil 10 is designed as an integrated whole.

[0065] The transmitting coil 2 is connected to the pulse generator 4, and the wireless transmission of the electromagnetic wave pulse signal (alternating magnetic field) is realized by adjusting the pulse electrical signal (output voltage) of the pulse generator;

[0066] The composite piezoelectric film comprises a bottom metal electrode 15, a piezoelectric coating 14, a top metal electrode 16, and a protective layer 17. The middle layer is a piezoelectric coating, which is located between the bottom electrode and the top electrode. The other ends of the bottom electrode and the top electrode are respectively connected to the two ends of the spiral sensor coil 10, so that the piezoelectric coating and the two electrode layers form a capacitor. Figure 2 .

[0067] The spiral sensor coil and the composite piezoelectric film form a loop as an antenna, such as Figure 2 It has three functions: ① Based on electromagnetic induction and infinite coupling, the spiral sensor coil converts the alternating magnetic field into an electrical signal; ② Based on the inverse piezoelectric effect, the composite piezoelectric film converts the induced voltage into an ultrasonic transmission wave; ③ The ultrasonic signal generated by the piezoelectric film is wirelessly transmitted and received, and the ultrasonic reflected wave is reflected back after being transmitted through the turbine blades, and the ultrasonic reflected wave is converted back into an electrical signal, which is then converted into an electromagnetic wave by the spiral sensor coil.

[0068] The receiving coil is connected to the host to realize the wireless reception of the converted electromagnetic signal.

[0069] The coil core is a high-frequency ferrite core and a ferrite coil core, which is used to increase the inductance of the coil and improve the conversion efficiency of electromagnetic energy-electrical energy.

[0070] Radio-transparent ceramic glass windows are used to direct the electromagnetic signal from the transmitting coil into the turbine blades.

[0071] Example 3

[0072] This embodiment provides a method for preparing a turbine blade, a composite piezoelectric film sensor, and a spiral sensor coil in an integrated manner. Figure 4-Figure 6 , the steps are as follows:

[0073] (1) depositing a bottom metal electrode 15 on the surface of the turbine blade 11;

[0074] (2) depositing a piezoelectric coating 14;

[0075] (3) depositing the top spiral sensing coil 10 and the top metal electrode 16 simultaneously;

[0076] (4) Deposition of protective layer 17.

[0077] The bottom metal electrode, piezoelectric coating, spiral sensing coil, top metal electrode, and protective layer are all prepared by radio frequency magnetron sputtering technology.

[0078] The composite piezoelectric film includes a piezoelectric coating, a bottom metal electrode, a top metal electrode, and a protective layer. The middle layer is a piezoelectric coating. The piezoelectric coating is between the bottom electrode and the top electrode, and the other ends of the bottom electrode and the top electrode are respectively connected to the two ends of the spiral sensing coil, so that the piezoelectric coating and the two electrode layers form a capacitor. Under the action of the alternating magnetic field, the spiral sensing coil converts the received electromagnetic signal into an induced voltage to provide an electrical signal to the piezoelectric layer.

[0079] The top electrode, the piezoelectric layer, the bottom electrode and the spiral sensing coil form a closed circuit. The spiral sensing coil is used to receive the electromagnetic power from the transmitting coil and generate a sufficiently high voltage for the piezoelectric layer; and convert the converted electrical signal back into electromagnetic waves.

[0080] The bottom metal electrode can be Ag, Cr, Mo, chromium-nickel-iron alloy, etc., with a thickness of about 0.5-5 microns; deposition parameters: using corresponding pure target material, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250℃, deposition time between 0.5h-2h, and the distance between target and substrate between 5cm-10cm.

[0081] The piezoelectric coating can be other piezoelectric materials such as AlN, AlScN, LiNbO3, LiTaO3, ZnO, PZT, etc., and will also serve as a protective layer for the bottom metal electrode, with a thickness of about 8-25 microns; deposition parameters: using corresponding pure target materials, RF power between 700-1500W, deposition pressure between 0.5-4Pa, Ar / N2 between 1 / 2-5 / 1 or Ar / O2 between 1 / 2-5 / 1 (nitrides use Ar and N2, oxides use Ar and O2), chamber temperature between 100-250°C, deposition time between 2h-10h, and the distance between the target and the substrate between 2cm-7cm.

[0082] The spiral sensing coil can be made of Ag, Cr, Mo, chromium-nickel-iron alloy, etc., with a thickness of about 1-10 microns. One end of the spiral electrode will be connected to the bottom electrode, and the other end will be connected to the top electrode (the square area in the center of the piezoelectric layer); deposition parameters: using corresponding pure target materials, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250℃, deposition time between 1h-4h, and the distance between the target material and the substrate between 3cm-7cm.

[0083] The top metal electrode can be Ag, Cr, Mo, chromium-nickel-inconel alloy, etc., with a thickness of about 10-30 microns. Deposition parameters: using corresponding pure target materials, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon, chamber temperature between 80-250℃, deposition time between 2h-12h, and the distance between the target and the substrate between 3cm-7cm.

[0084] The protective layer can be AlN, AlCrO, Al2O3, SiO2, which is used to encapsulate and protect sensors, coils and top electrodes, with a thickness of about 20-40 microns. Deposition parameters: using the corresponding pure target material, RF power between 700-1000W, deposition pressure between 0.5-4Pa, Ar / N2 between 1 / 2-5 / 1 or Ar / O2 between 1 / 2-5 / 1 (nitride uses Ar and N2, oxide uses Ar and O2), chamber temperature between 100-250℃, deposition time between 5h-20h, and the distance between the target and the substrate between 2cm-7cm.

Claims

1. A wireless ultrasonic measurement system design method, characterized in that: The system is applied to high-speed rotating aircraft engine turbine blades to realize wireless ultrasonic transmission and reception, and to monitor the load and temperature of the object to be measured; the system comprises an instrument end and a sensor end, the instrument end is composed of a host, i.e., a monitoring system, a transmitting coil, a receiving coil, a coil core, and a pulse generator, and the sensor end is an integrated design and preparation of a turbine blade, a composite piezoelectric film on the end face of the turbine blade, and a spiral sensor coil; the integrated preparation method of the turbine blade, the composite piezoelectric film, and the spiral sensor coil comprises the following steps: S1: Deposition of bottom metal electrode on the surface of turbine blade; S2: depositing piezoelectric coating; S3: Simultaneous deposition of the top spiral sensing coil and the top metal electrode; S4: depositing protective layer; The bottom metal electrode, piezoelectric coating, spiral sensor coil, top metal electrode and protective layer are all prepared by radio frequency magnetron sputtering technology; The composite piezoelectric film comprises a piezoelectric coating, a bottom metal electrode, a top metal electrode, and a protective layer, wherein the middle layer is the piezoelectric coating, and the piezoelectric coating is located between the bottom electrode and the top electrode, and the other ends of the bottom electrode and the top electrode are respectively connected to the two ends of the spiral sensing coil, so that the piezoelectric coating and the two electrode layers form a capacitor, and under the action of an alternating magnetic field, the electromagnetic signal received by the spiral sensing coil is converted into an induced voltage, providing an electrical signal to the piezoelectric layer; The top electrode, the piezoelectric layer, the bottom electrode and the spiral sensing coil form a closed circuit. The spiral sensing coil is used to receive the electromagnetic power from the transmitting coil and generate a sufficiently high voltage for the piezoelectric layer; and convert the converted electrical signal back into an electromagnetic wave.

2. The wireless ultrasonic measurement system design method according to claim 1, characterized in that: The bottom metal electrode is any one of Ag, Cr, Mo or chromium-nickel-iron alloy, with a thickness of 0.5-5 microns; deposition parameters: using corresponding pure target material, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250°C, deposition time between 0.5h-2h, and the distance between the target material and the substrate between 5cm-10cm; The piezoelectric coating is any one of AlN, AlScN, LiNbO3, LiTaO3, ZnO or PZT, and will also serve as a protective layer for the bottom metal electrode, with a thickness of 8-25 microns; deposition parameters: using corresponding pure target materials, RF power between 700-1500W, deposition pressure between 0.5-4Pa, Ar / N2 between 1 / 2-5 / 1 or Ar / O2 between 1 / 2-5 / 1, chamber temperature between 100-250°C, deposition time between 2h-10h, and the distance between the target material and the substrate between 2cm-7cm; The spiral sensing coil is any one of Ag, Cr, Mo or chromium-nickel-iron alloy, with a thickness of 1-10 microns. One end of the spiral electrode will be connected to the bottom electrode, and the other end will be connected to the top electrode, i.e., the square area in the center of the piezoelectric layer. Deposition parameters: using corresponding pure target material, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250°C, deposition time between 1h-4h, and the distance between the target material and the substrate between 3cm-7cm. The top metal electrode is any one of Ag, Cr, Mo or chromium-nickel-iron alloy, with a thickness of 10-30 microns; deposition parameters: using corresponding pure target material, RF power between 500-1000W, deposition pressure between 0.5-2Pa, pure argon gas, chamber temperature between 80-250°C, deposition time between 2h-12h, and the distance between the target material and the substrate between 3cm-7cm; The protective layer is any one of AlN, AlCrO, Al2O3 or SiO2, used for encapsulating and protecting sensors, coils and top electrodes, with a thickness of 20-40 microns; deposition parameters: using corresponding pure target materials, RF power between 700-1000W, deposition pressure between 0.5-4Pa, Ar / N2 between 1 / 2-5 / 1 or Ar / O2 between 1 / 2-5 / 1, chamber temperature between 100-250°C, deposition time between 5h-20h, and the distance between the target material and the substrate between 2cm-7cm.

3. A wireless ultrasonic measurement system based on the design method of claim 2, characterized in that: It includes an instrument end and a sensor end. The instrument end is composed of a host, i.e., a monitoring system, a transmitting coil, a receiving coil, a coil core, and a pulse generator. The sensor end is an integrated structure of a turbine blade, a composite piezoelectric film on the end face of the turbine blade, and a spiral sensor coil: The transmitting coil is connected to the pulse generator, and the wireless transmission of the electromagnetic wave pulse signal, i.e. the alternating magnetic field, is achieved by adjusting the pulse electrical signal of the pulse generator; The spiral sensor coil and the composite piezoelectric film form a loop, which acts as an antenna to wirelessly transmit and receive ultrasonic signals generated by the piezoelectric film; The receiving coil is connected to the host to achieve wireless reception of the converted electromagnetic signal; The coil core is a high-frequency ferrite core or a ferrite coil core, which is used to increase the inductance of the coil and improve the conversion efficiency of electromagnetic energy to electrical energy; The radio-transparent ceramic glass window is used to introduce electromagnetic signals from the transmitting coil into the turbine blade.

4. A wireless ultrasonic measurement method, characterized in that: The wireless ultrasonic measurement system according to claim 3 comprises the following steps: 1) The transmitting coil is connected to the pulse generator to realize the wireless transmission of the electromagnetic wave pulse signal, and the alternating magnetic field is obtained by adjusting the pulse output voltage of the pulse generator; 2) The spiral sensor coil converts the received fluctuating electromagnetic waves, i.e. the alternating magnetic field, into an electrical signal, i.e. the induced voltage; 3) The composite piezoelectric film sensor converts electrical signals into ultrasonic transmission waves based on the inverse piezoelectric effect; 4) The ultrasonic transmission wave is transmitted in the turbine blade and reflected back, which is called the ultrasonic reflection wave; 5) The composite piezoelectric film sensor converts ultrasonic reflected waves back into electrical signals based on the piezoelectric effect; 6) The electrical signal will be converted into electromagnetic waves by the spiral sensing coil and received by the receiving coil; 7) The signal from the receiving coil will be further processed by the controller and displayed on the computer terminal using Lab View software.

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