Arbitrary curvature container pressure measurement system and measurement method based on acoustic impedance analysis

Abstract

The invention discloses an arbitrary curvature container pressure measurement system and method based on acoustic impedance analysis, and the system comprises a measurement assembly, a power unit, a control unit, a signal source, a data processing unit, a data output unit, and a calibration assembly. The measuring assembly comprises an ultrasonic transducer for emitting ultrasonic waves and an ultrasonic transducer for receiving ultrasonic signals, the ultrasonic transducers are installed on the outer surface of the container, structural damage to the container is not needed, the control unit is responsible for exciting the ultrasonic transducers and regulating and controlling working parameters of the ultrasonic transducers, and the data processing unit receives and processes the ultrasonic signals. Measurement data are analyzed and calculated through a mathematical model, a container pressure measurement result is finally output, and the power supply unit and the data output unit respectively supply power to the system and provide a real-time display or remote transmission function of the measurement result. According to the invention, based on acoustic impedance analysis, accurate measurement of the pressure of the container with any curvature can be realized, and the reliability and precision of ultrasonic measurement of the pressure of the container can be improved.

Description

Technical Field

[0001] The present invention relates to the field of ultrasonic detection and measurement technology, and in particular to a pressure measurement system and a measurement method for a container with arbitrary curvature based on acoustic impedance analysis. Background Art

[0002] In industrial production and scientific research, accurate measurement of the absolute pressure of a container is a crucial technology, which is widely used in the fields of pressure vessel inspection, gas storage monitoring and MEMS sensor equipment status assessment. Existing pressure measurement methods include traditional contact pressure measurement methods that rely on mechanical pressure gauges or pressure sensors based on principles such as resistance and capacitance; optical pressure measurement methods that use fiber optic sensors or interferometers to measure the refraction, interference or scattering characteristics of light in different media to achieve pressure parameter inversion; and acoustic methods that can non-destructively invert the physical parameters of the target medium by analyzing the propagation behavior of ultrasonic waves in the medium (such as attenuation, reflection and transmission characteristics).

[0003] However, traditional contact pressure measurement methods are prone to destroying the structural integrity of the container; existing optical pressure measurement methods are generally suitable for containers with regular geometric shapes. For containers with complex curvatures, the complexity of optical path design and modeling increases significantly, making it difficult to meet the requirements of precise measurement; existing acoustic methods are also mainly aimed at containers with regular geometric structures, and no complete measurement solution has yet been formed for containers with complex curvatures. Especially under complex curvature conditions, the energy of ultrasonic signals is significantly attenuated after multiple reflections and transmissions, and the signal strength at the receiving end drops significantly, making it more difficult to extract effective information. At the same time, the shapes of the inner and outer surfaces of complex curvatures significantly affect the propagation path and energy distribution of sound waves, while existing acoustic propagation models are generally based on simple geometric assumptions and are difficult to accurately describe actual complex curvature conditions.

[0004] In summary, with the increasing application demand for complex curvature containers and special working conditions (such as high temperature, high pressure or corrosive environment), the existing pressure measurement methods have problems such as damage to the container structure under these conditions, decreased measurement accuracy under complex curvature conditions, and insufficient adaptability to dynamic environments. Summary of the invention

[0005] The present invention provides a method and system for measuring pressure of a container with arbitrary curvature based on acoustic impedance analysis, which can adapt to complex curvatures and changeable environmental conditions and ensure the accuracy and reliability of container pressure measurement without damaging the container structure.

[0006] To solve the above technical problems, an embodiment of the present invention provides a pressure measurement system for a container with arbitrary curvature based on acoustic impedance analysis, comprising a measurement component, a power supply unit, a control unit, a signal source, and a data processing unit; wherein the measurement component comprises at least one transmitting end ultrasonic transducer, at least one receiving end ultrasonic transducer, and an external sensor; The transmitting end ultrasonic transducer is used to generate an ultrasonic signal and transmit the ultrasonic signal to the inner surface of the container to be tested at a preset incident angle; The receiving end ultrasonic transducer is used to receive the ultrasonic signal attenuated after being reflected and transmitted through the inner and outer surfaces of the container to be tested; The external sensor is used to obtain external parameters of the container to be tested; The power supply unit is used to provide power to the system; The control unit is used to drive the signal source to provide an excitation signal to the transmitting end ultrasonic transducer and adjust the working parameters of the measuring component; The data processing unit is used to receive ultrasonic signals, perform acoustic impedance analysis on the container to be tested according to the interface reflection and transmission model, the sound wave attenuation model and the complex curvature propagation path model, extract the reflection coefficient and the amplitude attenuation characteristics, and calculate the internal pressure value or the external pressure value of the container to be tested according to the ideal gas state equation in combination with the calibration data and the external parameters of the container to be tested, so as to obtain the pressure measurement result of the container to be tested.

[0007] As an improvement of the above solution, the system further includes a data output unit and a calibration component, and the measurement component further includes a signal conditioning unit; The data output unit is used to output the pressure measurement result of the container to be tested; The calibration component is used to collect calibration data and correct the pressure measurement result of the container to be tested according to the external parameters of the container to be tested; The signal conditioning unit is used to condition the ultrasonic signal; The signal conditioning unit includes an ultrasonic transducer impedance matching circuit at the receiving end, an ultrasonic transducer signal amplifying circuit at the receiving end, an ultrasonic transducer voltage follower at the receiving end, and an ultrasonic transducer impedance matching circuit and an ultrasonic transducer equivalent circuit at the transmitting end.

[0008] As an improvement of the above solution, the incident angle The following conditions are met: ; in, , , They are the sound speeds of the gas inside the container to be tested, the material of the container to be tested, and the gas outside the container to be tested, respectively.

[0009] As an improvement of the above solution, in the data processing unit, the reflection coefficient is calculated by the following formula: ; ; in, , are the reflection coefficients of the inner and outer surfaces of the container to be tested, respectively; are the acoustic impedances of the inside of the container to be tested, the material of the container to be tested, and the outside of the container to be tested, respectively; The amplitude attenuation characteristic is the amplitude at the receiving end during measurement. The amplitude of the receiving end during calibration The ratio is calculated by the following formula: ; in, , are respectively the reflection coefficients of the inner and outer surfaces of the container to be measured during measurement; , are respectively the reflection coefficients of the inner and outer surfaces of the container to be measured during calibration; is the total number of reflections on the inner surface of the container to be tested; is the total number of reflections on the outer surface of the container to be tested.

[0010] As an improvement of the above solution, the total number of reflections on the inner surface of the container to be tested is solved by the following formula: ; ; ; ; in, is the path length of the ultrasonic signal propagating in the container wall to be tested, for Projection distance projected onto the outer surface of the container to be tested; It is the shortest distance between two points on the surface of the ultrasonic transducer at the transmitting end and the ultrasonic transducer at the receiving end during measurement, that is, the total projection distance of the ultrasonic signal; is the total propagation path length of the ultrasonic signal; For the The curvature of the inner surface of the container to be tested during the second reflection; For the The curvature of the outer surface of the container to be tested during the second reflection; is the total number of reflections of the ultrasonic signal; is the incident angle of the ultrasonic signal.

[0011] As an improvement of the above solution, the internal pressure value of the container to be tested is calculated by the following formula: ; in, is the internal pressure value of the container to be tested; is the ideal gas constant; The amplitude of the receiving end is used for calibration; is the amplitude at the receiving end during measurement; , , , , They are the molar mass of the gas inside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, and the temperature during measurement; , are the density and sound velocity of the container material to be tested respectively; , , , , , are the molar mass of the gas outside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, the pressure during measurement, and the temperature during measurement; is the total number of reflections on the inner surface of the container to be tested, is the total number of reflections on the outer surface of the container to be tested.

[0012] As an improvement of the above solution, the external pressure value of the container to be tested is calculated by the following formula: ; in, is the external pressure value of the container to be tested; is the ideal gas constant; The amplitude of the receiving end is used for calibration; is the amplitude at the receiving end during measurement; , , , , They are the molar mass of the gas inside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, and the temperature during measurement; , are the density and sound velocity of the container material to be tested respectively; , , , , , are the molar mass of the gas outside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, the pressure during measurement, and the temperature during measurement; is the total number of reflections on the inner surface of the container to be tested, is the total number of reflections on the outer surface of the container to be tested.

[0013] As an improvement of the above solution, the measuring component includes multiple groups of ultrasonic transducers, each group of ultrasonic transducers includes at least one transmitting end ultrasonic transducer and at least one receiving end ultrasonic transducer; The internal pressure value or external pressure value of the container to be tested is calculated by the following formula: ; in, is the internal pressure value or external pressure value of the container to be tested; For the An internal pressure value or an external pressure value of the container to be tested measured by a group of ultrasonic transducers; For the The weight coefficient of a group of ultrasonic transducers.

[0014] As an improvement of the above solution, the weight coefficient is calculated by the following formula: ; in, Indicates The curvature of the ultrasonic signal reflection path of the ultrasonic transducer group, Indicates The thickness uniformity of the container wall through which the transducer reflection path passes, Indicates Group transducer reflection path length; Indicates Comprehensive performance parameters of the group transducer.

[0015] To solve the above technical problems, an embodiment of the present invention further provides a method for measuring pressure of a container with arbitrary curvature based on acoustic impedance analysis, which is applied to the pressure measurement system for a container with arbitrary curvature based on acoustic impedance analysis as described above, comprising: Installing a transmitting end ultrasonic transducer and a receiving end ultrasonic transducer on the outer surface of the container to be tested; Collecting calibration data using a calibration component; The driving signal source excites the transmitting end ultrasonic transducer to emit an ultrasonic signal. The ultrasonic signal is propagated through the medium and collected by the receiving end ultrasonic transducer, and then transmitted to the data processing unit through the signal conditioning unit. Calculating the internal pressure value or the external pressure value of the container to be tested by the data processing unit to obtain the pressure measurement result of the container to be tested; The pressure measurement result is outputted through a data output unit.

[0016] Compared with the prior art, the embodiment of the present invention provides a pressure measurement system and method for an arbitrary curvature container based on acoustic impedance analysis, the system comprising a measurement component, a power supply unit, a control unit, a signal source, a data processing unit, a data output unit and a calibration component, the measurement component comprising an ultrasonic transducer for emitting ultrasonic waves and an ultrasonic transducer for receiving ultrasonic signals, both of which are installed on the outer surface of the container, and the container does not need to be structurally damaged, the control unit is responsible for exciting the ultrasonic transducer and regulating its working parameters, the data processing unit receives and processes the ultrasonic signal from the receiving end, and calculates the measurement data through mathematical model analysis, and finally outputs the container pressure measurement result, the power supply unit and the data output unit respectively power the system and provide real-time display or remote transmission of the measurement result. The present invention can accurately measure the absolute pressure of an arbitrary curvature container based on acoustic impedance analysis under the premise of non-destructive testing, avoiding the destructiveness of the traditional method to the container structure, while breaking through the limitations of the optical method in complex curvatures and harsh environments, and significantly improving the reliability and accuracy of ultrasonic measurement of container pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the drawings used in the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural block diagram of a pressure measurement system for a container with arbitrary curvature based on acoustic impedance analysis provided by an embodiment of the present invention; Figure 2 is a circuit structure diagram of a signal conditioning unit provided by an embodiment of the present invention; Figure 3 It is a flow chart of a method for measuring pressure of a container with arbitrary curvature based on acoustic impedance analysis provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of the measurement principle of a pressure measurement system for a container with arbitrary curvature based on acoustic impedance analysis provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1, Figure 1 1 is a structural block diagram of a pressure measurement system for an arbitrary curvature container based on acoustic impedance analysis provided by an embodiment of the present invention. Figure 1 As shown, the arbitrary curvature container pressure measurement system based on acoustic impedance analysis includes a measurement component 2, a power supply unit 3, a control unit 4, a signal source 5, a data processing unit 6, a data output unit 7 and a calibration component 8; wherein the measurement component 2 includes at least one transmitting end ultrasonic transducer 21, at least one receiving end ultrasonic transducer 22, an external sensor 23 and a signal conditioning unit 24; The transmitting end ultrasonic transducer 21 is used to generate an ultrasonic signal and transmit the ultrasonic signal to the inner surface of the container to be tested at a preset incident angle; The receiving end ultrasonic transducer 22 is used to receive the ultrasonic signal attenuated after being reflected and transmitted through the inner and outer surfaces of the container to be tested; The external sensor 23 is used to obtain external parameters of the container to be tested; The signal conditioning unit 24 is used to condition the ultrasonic signal to ensure the integrity and stability of the ultrasonic signal; The power supply unit 3 is used to provide power to the container pressure measurement system; The control unit 4 is used to drive the signal source 5 to provide an excitation signal to the transmitting end ultrasonic transducer 21, and to adjust the working parameters of the measuring component 2; The data processing unit 6 is used to receive the conditioned ultrasonic signal, perform acoustic impedance analysis on the container to be tested according to the interface reflection and transmission model, the sound wave attenuation model and the complex curvature propagation path model, extract the reflection coefficient and the amplitude attenuation characteristics, and calculate the internal pressure value or the external pressure value of the container to be tested according to the ideal gas state equation in combination with the calibration data and the external parameters of the container to be tested, so as to obtain the pressure measurement result of the container to be tested; The data output unit 7 is used to output the pressure measurement result of the container to be tested; illustratively, it is used to display, store or remotely transmit the pressure measurement result of the container in real time; The calibration component 8 is used to collect calibration data and to correct the pressure measurement result of the container to be measured according to the external parameters of the container to be measured; that is, it is used for dynamic calibration and compensation to ensure the reliability and accuracy of the system under complex working conditions.

[0021] It should be noted that, in specific implementation, the container pressure measurement system also includes a measurement object, that is, a container to be measured 1. The container to be measured 1 is used to store the environment to be measured (gas or liquid), and its curvature can be any curvature, such as a flat plate, sphere, cylinder or other complex geometric structures.

[0022] It is worth noting that the external sensor 23 includes a temperature sensor, an external pressure sensor, etc., which are used to obtain external parameters including temperature and external pressure.

[0023] See also Figure 2 , Figure 2 is a circuit structure diagram of a signal conditioning unit provided by an embodiment of the present invention, such as Figure 2 As shown, the signal conditioning unit 24 includes a receiving end ultrasonic transducer impedance matching circuit 241, a receiving end ultrasonic transducer signal amplifying circuit 242, a receiving end ultrasonic transducer voltage follower 243, a transmitting end ultrasonic transducer impedance matching circuit 244 and an ultrasonic transducer equivalent circuit 245.

[0024] Exemplarily, the transmitting end circuit includes a signal source 5, a transmitting end ultrasonic transducer 21, an ultrasonic transducer equivalent circuit 245 and a transmitting end ultrasonic transducer impedance matching circuit 244; the receiving end circuit includes a receiving end ultrasonic transducer 22, an ultrasonic transducer equivalent circuit 245, a receiving end ultrasonic transducer impedance matching circuit 241, a receiving end ultrasonic transducer signal amplification circuit 242 and a receiving end ultrasonic transducer voltage follower 243. The impedance matching circuits of the receiving end and the transmitting end are connected by adapting the inductor. and capacitor The parameters achieve efficient coupling between the transducer and the driving circuit and maximize the energy transmission efficiency.

[0025] It should be noted that the ultrasonic transducer equivalent circuit is the ultrasonic transducer as an ultrasonic detector or transmitter in practice. When excited in the circuit, it is generally equivalent to a combination of a capacitor and a resistor. In the embodiment of the present invention, the transmitter and the receiver both use the same type of transducer, and the resistance and capacitance values ​​on the equivalent circuits of the two transducers are equal. Therefore, the ultrasonic transducer equivalent circuit 245 is used to illustrate the transducer equivalent circuits of the transmitter and the receiver.

[0026] Specifically, Figure 2 As shown, the ultrasonic transducer equivalent circuit 245 can be simplified as an equivalent resistor and equivalent capacitance When the ultrasonic transducers at the transmitting and receiving ends have good consistency, the values ​​of their equivalent resistance and equivalent capacitance are the same, thus providing a consistent basis for the design of impedance matching circuits.

[0027] In order to achieve conjugate matching between the signal source and the ultrasonic transducer, so that the signal source can output the maximum power to the transducer load, a transmitting end ultrasonic transducer impedance matching circuit 244 is designed between the signal source and the load. Connect a capacitor in series , connect an inductor in parallel , forming a high-pass impedance matching circuit. Generally, in an impedance matching circuit, the values ​​of capacitors and inductors are calculated according to the following formula: ; in, is the operating frequency of the impedance matching circuit, By properly selecting the parameters of capacitors and inductors, the load impedance can be adjusted to a conjugate match of the signal source impedance, thereby improving the power transmission efficiency.

[0028] It should be noted that the receiving end ultrasonic transducer impedance matching circuit 241 and the ultrasonic transducer impedance matching circuit 244 adopt the same design structure. When the transmitting end and the receiving end ultrasonic transducers have good consistency, the capacitance and inductance parameters in the receiving end impedance matching circuit are the same as those of the transmitting end, that is, the relationship is satisfied: ; The matching network can effectively improve the quality of the received signal and increase the sensitivity of the receiving end signal.

[0029] For example, Figure 2 As shown, the signal amplification circuit 242 uses an operational amplifier , adjustable resistor and By adjusting the resistance and , the amplification factor can be changed to meet the signal gain requirements of different application scenarios. The expression of the amplification factor is: ; in, is the output signal voltage of the ultrasonic transducer 22 at the receiving end, is the output signal voltage after amplification. By selecting the resistance parameters according to actual needs, high-sensitivity amplification of ultrasonic signals can be achieved.

[0030] Furthermore, the output of the receiving end ultrasonic transducer signal amplification circuit 242 is connected to the receiving end ultrasonic transducer voltage follower 243, which is composed of an operational amplifier The input end receives the amplified signal, and the output end provides signal input for the data processing unit 6. The main function of the voltage follower is to achieve the characteristics of high input impedance and low output impedance, provide stable signal transmission capability, and ensure the accuracy and stability of subsequent data processing.

[0031] Specifically, the signal source 5 is used to drive the transmitting end ultrasonic transducer 21 to generate an ultrasonic signal of predetermined frequency and amplitude; the control unit 4 is used to dynamically adjust the frequency of the signal source 5 to adapt to different container materials to be tested and different measurement environment conditions; the external sensor 23 is used to monitor the internal and external environmental parameters of the container in real time, and provide dynamic correction input to ensure measurement accuracy.

[0032] Based on the above-mentioned system items, the present invention provides corresponding embodiments of the method items.

[0033] See also Figure 3 , Figure 3 FIG. 1 is a flow chart of a method for measuring pressure of a container with arbitrary curvature based on acoustic impedance analysis provided by an embodiment of the present invention. Figure 3 As shown, the measuring method comprises steps S1 to S5: S1. Install the transmitting end ultrasonic transducer and the receiving end ultrasonic transducer on the outer surface of the container to be tested; For example, the container pressure measurement system is initialized and installed. According to the geometric characteristics and working conditions of the container to be measured, a suitable ultrasonic transducer model is selected and installed on the outer surface of the container to be measured, and the distance between the transmitting end and the receiving end is recorded. , that is, the geodesic distance between the transmitting ultrasonic transducer and the receiving ultrasonic transducer, or the shortest path distance between two points on the surface of the two.

[0034] It is worth noting that the transducer in the embodiment of the present invention can be fixed to the container surface by a mechanical clamping device or epoxy resin adhesive, which has a better coupling effect, lower signal loss, and is non-destructive to the container to be tested.

[0035] S2. Collect calibration data using the calibration component; Exemplarily, the calibration component 8 is used to obtain internal and external gas parameters (such as pressure, temperature, and sound velocity) and container material parameters (such as density, elastic modulus, and sound velocity) through a calibration process, and a dynamic correlation between the container characteristic parameters and the acoustic impedance is established in combination with the signal amplitude of the ultrasonic transducer during the calibration.

[0036] S3, the driving signal source excites the transmitting end ultrasonic transducer to emit an ultrasonic signal, the ultrasonic signal is propagated through the medium and collected by the receiving end ultrasonic transducer, and then transmitted to the data processing unit through the signal conditioning unit; Exemplarily, the driving signal source 5 excites the transmitting end ultrasonic transducer 21 to emit an ultrasonic signal, and the ultrasonic signal propagates through the medium and is collected by the receiving end ultrasonic transducer 22 , and is transmitted to the data processing unit 6 through the signal conditioning unit 24 .

[0037] S4, calculating the internal pressure value or the external pressure value of the container to be tested by the data processing unit to obtain the pressure measurement result of the container to be tested; Exemplarily, mathematical modeling and calculation are performed by the data processing unit 6, and the amplitude attenuation characteristics and reflection coefficients in the signal are extracted according to the sound wave attenuation model, the interface reflection and transmission model, and the complex curvature propagation path model, and the absolute pressure of the container is calculated in combination with the calibration data and real-time parameters.

[0038] S5. Output the pressure measurement result through a data output unit.

[0039] Exemplarily, the measurement result is displayed on a user interface through the data output unit 7, or is remotely transmitted to a control center by wireless means.

[0040] In summary, an embodiment of the present invention provides a system and method for measuring pressure of a container with arbitrary curvature based on acoustic impedance analysis. The system includes a measuring component, a power supply unit, a control unit, a signal source, a data processing unit, a data output unit and a calibration component. The measuring component includes an ultrasonic transducer for emitting ultrasonic waves and an ultrasonic transducer for receiving ultrasonic signals. The two are installed on the outer surface of the container without structural damage to the container. The control unit is responsible for exciting the ultrasonic transducer and regulating its working parameters. The data processing unit receives and processes the ultrasonic signal from the receiving end, and calculates the measurement data through mathematical model analysis, and finally outputs the container pressure measurement result. The power supply unit and the data output unit respectively power the system and provide real-time display or remote transmission of the measurement results. The method first installs ultrasonic transducers and measures the geodesic distance between the transducers; secondly, obtains gas parameters (such as pressure, temperature, and sound velocity) inside and outside the container and container material parameters (such as density, elastic modulus, and sound velocity) through the calibration process of the calibration component; then, actual measurement is performed to calculate the acoustic impedance ratio inside and outside the container through the reflection and transmission amplitude ratio of the ultrasonic signal; finally, the relevant parameters are substituted into the constructed mathematical model to invert the absolute pressure values ​​inside and outside the container. If the external pressure parameters are known, the internal pressure is measured; and vice versa.

[0041] The present invention can accurately measure the absolute pressure of containers with arbitrary curvature based on acoustic impedance analysis under the premise of non-destructive testing, avoiding the destructive dependence of traditional methods on the container structure. At the same time, it breaks through the limitations of optical methods in complex curvatures and harsh environments, and can significantly improve the reliability and accuracy of container pressure measurement.

[0042] In order to achieve accurate measurement of the internal and external pressure of a complex curvature container, the present invention adopts ultrasound as a detection method, and constructs an interface reflection and transmission model, an acoustic wave attenuation model, a complex curvature propagation path model, a pressure inversion model, and a mathematical framework for dynamic calibration through acoustic impedance analysis, reflection and transmission characteristics research, and energy attenuation law. The following describes in detail the derivation process of these models and clarifies the core calculation logic of the data processing unit in the specific implementation.

[0043] See also Figure 4 , Figure 4 It is a schematic diagram of the measurement principle of a pressure measurement system for a container with arbitrary curvature based on acoustic impedance analysis provided by an embodiment of the present invention.

[0044] like Figure 4 As shown, during the measurement process, the ultrasonic signal is transmitted by the ultrasonic transducer 21 at a certain incident angle. Enter the container wall 12 and undergo multiple reflections and transmissions in the container wall. The specific propagation path and sound wave behavior follow the following physical laws: Interface reflection and transmission model: For example, the interior of the container 11 is medium 1, the container wall (i.e., the container material to be tested) 12 is medium 2, and the exterior of the container 13 is medium 3. The sound velocities of the three are respectively According to Snell's law, the angle of incidence , Reflection Angle and transmission refraction angle Satisfy between: ; ; ; in, represents the refraction angle of the ultrasonic wave transmitted from the surface of the container wall to the inside of the container, where It indicates the refraction angle of ultrasonic waves transmitted from the outer surface of the container to the outside of the container.

[0045] Preferably, in order to avoid total reflection and ensure the acquisition of multiple reflection signals, in an optional embodiment, the incident angle of the ultrasonic signal during measurement is The following conditions are met: .

[0046] Complex curvature propagation path model: After each reflection, the path length of the ultrasonic wave in medium 2 is and the projection distance of the path onto the outer surface for: ; ; Therefore, the total propagation path length and the total projection distance are: ; ; in, For the Secondary reflection path The geodesic curvature of the inner surface projection (i.e. The curvature of the inner surface of the container to be measured during the second reflection), For the Secondary reflection path The geodesic curvature of the corresponding outer surface projection (i.e. The curvature of the outer surface of the container to be measured during the second reflection).

[0047] In particular, for a flat plate structure or a concentric cylindrical structure, each reflection and for: Acoustic Impedance Analysis: In each interface transmission and reflection, the amplitude of the sound wave is determined by the sound pressure reflection coefficient and transmission coefficient change: Inner surface of container: ; Outer surface of container: ; Among them, are the acoustic impedances of medium 1, medium 2, and medium 3 respectively.

[0048] Furthermore, assuming that both the internal medium 1 and the external medium 3 of the container are gases, combined with the ideal gas state equation, we obtain: ; in, are the gas densities of medium 1, medium 2, and medium 3 respectively, , , is the pressure, molar mass and temperature of the gas inside the container; , , The pressure, molar mass, and temperature of the gas outside the container.

[0049] Amplitude attenuation and energy consumption model: During the propagation process, the amplitude of ultrasonic waves is affected by many factors, mainly including various types of attenuation and energy loss caused by multiple reflections and transmissions. Specifically, the sound wave attenuation model is: ; in, is the attenuation caused by heat dissipation, is the attenuation caused by lattice point defects, is the attenuation caused by particle scattering, is the attenuation caused by viscous damping.

[0050] In practice, the attenuation coefficient is usually measured by the exponential decay law of the ultrasonic amplitude with the propagation distance, that is: ; in, is the initial amplitude, is the overall attenuation coefficient, which is related to the medium characteristics, is the propagation distance of ultrasound in the medium.

[0051] Combined with the sound wave attenuation model, considering the ultrasonic transmission loss, the total amplitude change of the sound wave in multiple reflections in the container wall can be expressed as: ; in, is the total number of reflections on the inner surface of the container, is the total number of reflections on the outer surface of the container.

[0052] Pressure inversion model: Using the definition of acoustic impedance, the absolute pressure inside and outside the container can be inverted through the acoustic impedance inside and outside the container combined with the ideal gas state equation.

[0053] Specifically, during the calibration phase, the attenuation of the propagation distance, reflection (reflection on the inner surface times, reflected on the outer surface The same is true for transmission. Then the amplitude at the receiving end is: ; in, The amplitude of the receiving end during calibration.

[0054] During calibration, the parameters of the internal and external gases are known, and the ideal gas state equation is introduced ,get: ; The receiving end amplitude is measured for: ; By introducing the calibration formula for comparison, we can obtain the amplitude attenuation characteristic, namely: ; Right now: ; in, ( )、 ( ) are respectively the reflection coefficients of the inner and outer surfaces of the container to be measured; ( )、 ( ) are respectively the reflection coefficients of the inner and outer surfaces of the container to be measured during calibration; is the total number of reflections on the inner surface of the container to be tested; is the total number of reflections on the outer surface of the container to be tested.

[0055] It should be noted that, usually, the container pressure measurement system is only used to measure the data on one side of the container, that is, inside or outside the container. or Known.

[0056] So suppose If the gas parameters (temperature, pressure, molar mass and sound velocity) outside the container to be tested are known, then: ; Then substitute the above parameters into the ideal gas state equation , and simplified to obtain the mathematical model for measuring the absolute pressure of any gas inside a container with any curvature based on acoustic impedance analysis: ; in, is the internal pressure value of the container to be tested; is the ideal gas constant; The amplitude of the receiving end is used for calibration; is the amplitude at the receiving end during measurement; , , , , They are the molar mass of the gas inside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, and the temperature during measurement; , are the density and sound velocity of the container material to be tested respectively; , , , , , are the molar mass of the gas outside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, the pressure during measurement, and the temperature during measurement; is the total number of reflections on the inner surface of the container to be tested, is the total number of reflections on the outer surface of the container to be tested.

[0057] Therefore, the total number of reflections of the container to be tested is , whose value is obtained through Solve, where For the The curvature of the inner surface at the second reflection, For the The curvature of the outer surface at the second reflection.

[0058] In particular, when the container to be tested is a flat plate, , is the thickness of the plate, so the total number of reflections at this time is ; For a cylindrical container, , that is, the outer radius and the inner radius The total number of reflections is ; Furthermore, if the external gas parameters during calibration are consistent with those during measurement, that is, the gas molar mass, sound velocity, pressure and temperature do not change, the above-mentioned mathematical model for measuring the absolute pressure of any gas inside a container of arbitrary curvature based on acoustic impedance analysis can be simplified to: ; At this point, to know the internal gas pressure value of the container to be tested, you only need to know its internal gas parameters , container parameters , and the number of internal surface reflections That's it.

[0059] At this time, for a flat plate or cylinder, the corresponding mathematical model for measuring the absolute pressure of the gas inside the container is: flat: ; Cylinder: ; In actual measurements, since the external environment may change dynamically (such as temperature fluctuations and changes in container material parameters), the model needs to be dynamically calibrated and parameter optimized.

[0060] Therefore, the embodiment of the present invention obtains the external pressure in real time through the external sensor 23. ,temperature and container wall temperature Then the external pressure is calibrated by the calibration component 8. ,temperature and container wall temperature As input parameters, the values ​​of corresponding parameters in the model are dynamically adjusted and introduced into the acoustic impedance calculation formula to correct the pressure calculation results of the container.

[0061] Similarly, the arbitrary curvature container pressure measurement system based on acoustic impedance analysis provided by the embodiment of the present invention can also be used to detect the absolute pressure of the external environment of the container. The mathematical model for measuring the absolute pressure of any gas outside the arbitrary curvature container based on acoustic impedance analysis can be converted from the above-mentioned internal pressure measurement mathematical model: ; in, is the external pressure value of the container to be tested; is the ideal gas constant; The amplitude of the receiving end is used for calibration; is the amplitude at the receiving end during measurement; , , , , They are the molar mass of the gas inside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, and the temperature during measurement; , are the density and sound velocity of the container material to be tested respectively; , , , , , are the molar mass of the gas outside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, the pressure during measurement, and the temperature during measurement; is the total number of reflections on the inner surface of the container to be tested, is the total number of reflections on the outer surface of the container to be tested.

[0062] It should be noted that the method for calculating the number of reflections is consistent with the method for measuring the internal pressure of a container, and will not be repeated here.

[0063] Furthermore, if the gas parameters inside the container are consistent during calibration and measurement, that is, the gas molar mass, sound velocity, pressure and temperature do not change, then the above-mentioned mathematical model for measuring the absolute pressure of any gas outside a container of arbitrary curvature based on acoustic impedance analysis can be simplified to: ; Furthermore, for a flat plate or cylindrical container, the corresponding mathematical model for measuring the absolute pressure of the gas outside the container is: flat: ; Cylinder: ; Through numerical simulation and theoretical verification, the mathematical model for measuring the internal and external pressure of the container provided by the embodiment of the present invention shows good adaptability and high precision in the measurement under different curvature, temperature and pressure conditions, especially showing significant technical advantages under high temperature and high pressure environment. The derivation of the above theory and mathematical model provides a reliable scientific basis for the technical realization of the present invention, ensuring the wide applicability of the method in industrial detection and special environment pressure measurement.

[0064] In a preferred embodiment, the measuring assembly includes a plurality of groups of ultrasonic transducers, each group of ultrasonic transducers includes at least one transmitting end ultrasonic transducer and at least one receiving end ultrasonic transducer; At this time, the internal pressure value or external pressure value of the container to be tested is calculated by the following formula: ; in, is the internal pressure value or external pressure value of the container to be tested; For the An internal pressure value or an external pressure value of the container to be tested measured by a group of ultrasonic transducers; For the The weight coefficient of a group of ultrasonic transducers.

[0065] It should be noted that the weight coefficient The selection is mainly based on the transducer layout conditions and the correlation of transducer performance. For transducer layout conditions: when the transducer layout conditions are the same (such as the curvature of the ultrasonic propagation path is consistent, the transducer parameters are the same, etc.), the weight coefficient is equally distributed among all transducer groups, i.e. ,in This situation is applicable to containers of regular shapes (such as spherical, cylindrical, and flat) and the transducers are arranged in symmetrical positions.

[0066] However, in the case of inconsistent arrangement conditions, the weights of each group of transducers should be dynamically adjusted according to the specific characteristics to compensate for the measurement errors caused by differences in transducer parameters and ultrasonic propagation conditions. First, the curvature of the ultrasonic propagation path is an important factor affecting signal quality. The smaller the path curvature, the lower the ultrasonic propagation loss, and the higher the calculation accuracy of its reflection and refraction path, so the weight should be increased accordingly; while the path with a larger curvature increases the error due to attenuation and multiple reflections, and its weight should be reduced. Secondly, the uniformity of the container wall is also an important basis for weight distribution. When the transducers are arranged at a position with uniform wall thickness, the ultrasonic propagation path is more stable, which can improve the reliability of absolute pressure calculation, and such transducer groups should be given a higher weight. For path length, the shorter path has less ultrasonic loss and higher signal fidelity, so the transducer group with a shorter path has a higher weight, while the weight of the group with a longer path is correspondingly reduced.

[0067] In addition, the performance differences of the transducers themselves will also significantly affect the distribution of weights. Transducers with high frequencies and low emission angles usually have higher resolutions and better anti-interference capabilities, and their weights should be increased; while transducers with poor fit or low frequencies have poor signal quality and their weights should be reduced. The way the transducer is fixed also requires special consideration. Transducers fixed with mechanical clamps or epoxy resin glue have better coupling effects with the container surface and lower signal loss, so they should be given higher weights.

[0068] To further optimize the weight distribution, the embodiment of the present invention combines the experimental calibration method to dynamically calibrate the weight calculation formula. In actual operation, the functional relationship between the weight and the path curvature, thickness uniformity, path length and transducer performance parameters can be established by measuring the experimental data of known pressure points and using fitting methods (such as least squares method) or machine learning models. Finally, the weight coefficient is calculated by the following formula: ; in, Indicates The curvature of the ultrasonic signal reflection path of the ultrasonic transducer group, Indicates The thickness uniformity of the container wall through which the transducer reflection path passes, Indicates Group transducer reflection path length; Indicates The comprehensive performance parameters of a group of transducers (including frequency, emission angle and coupling performance).

[0069] It is worth noting that, by dynamically adjusting the weight distribution, the embodiment of the present invention can effectively improve the accuracy and reliability of the absolute pressure measurement inside and outside the complex curvature container.

[0070] In summary, the present invention uses ultrasound as a detection method, and utilizes its reflection and transmission laws between multi-media interfaces, as well as the exponential attenuation law of its amplitude with propagation distance, to construct a sound wave attenuation model and a reflection and transmission model. By comprehensively analyzing the acoustic impedance characteristics of the gas and materials inside and outside the container, combined with the parameter correction in the dynamic calibration process, the accurate calculation of the absolute pressure of the container is achieved.

[0071] Specifically, in the acoustic wave attenuation model, the energy loss caused by heat dissipation, viscous damping, particle scattering and lattice point defects is comprehensively considered; in the interface reflection and transmission model, the sound pressure reflection coefficient and transmission coefficient are calculated through the dynamic changes of the curvature of the inner and outer surfaces of the container and the acoustic impedance of the medium; in the complex curvature propagation path model, the propagation path length, number of reflections and total energy loss of ultrasonic waves under different curvatures are considered to ensure that the model is adapted to the pressure measurement requirements under complex geometric structures. In addition, based on Snell's law, the incident angle range of ultrasonic waves is optimized to avoid the occurrence of total reflection.

[0072] It is worth mentioning that the present invention is particularly suitable for measuring the internal pressure of a container with complex curvature, and can adapt to a variety of working conditions, including extreme conditions such as high temperature, high pressure or corrosive gas.

[0073] The present invention constructs a mathematical model for measuring the absolute pressure inside a container, which combines the propagation characteristics of sound waves with the dynamic environmental correction inside and outside the container. By real-time monitoring the physical parameters of the gas and liquid inside and outside the container (such as temperature, density, speed of sound, etc.), combined with the acoustic impedance ratio and the reflection and transmission characteristics of the ultrasonic signal, the absolute pressure inside the container is accurately calculated. Specifically, the acoustic impedance characteristics inside and outside the container have a direct impact on the propagation of the ultrasonic signal, and the reflection and transmission amplitude ratio can reflect the pressure difference inside and outside the container. By establishing an inversion model based on the acoustic impedance ratio and the amplitude of the ultrasonic signal, and combining the environmental correction in the dynamic calibration process, the absolute pressure value inside the container can be calculated in real time. This dynamic measurement model can adapt to various changing conditions, such as temperature fluctuations, pressure changes, and changes in gas composition, to ensure the accuracy and reliability of pressure measurement.

[0074] Among them, the measurement model is calculated and corrected through the following key factors: Acoustic impedance correction: Eliminate the influence of different media on sound wave propagation through real-time acoustic impedance correction of gas, liquid or solid materials inside and outside the container.

[0075] Dynamic temperature and pressure compensation: Temperature changes and external pressure changes directly affect the propagation speed and attenuation of sound waves. Therefore, real-time temperature and pressure compensation corrections are performed to ensure measurement accuracy.

[0076] Reflection and transmission signal processing: The amplitude ratio of reflection and transmission is used in combination with mathematical models for accurate inversion to calculate the absolute pressure value inside the container.

[0077] The measurement model combines the real-time feedback ultrasonic signal with the environmental correction parameters to obtain the most accurate absolute pressure inside the container.

[0078] In summary, compared with the prior art, the embodiments of the present invention have the following technical advantages: Non-contact and non-destructive: The measurement process does not require opening holes in the container or destroying the structural integrity, and is suitable for high pressure, high temperature and corrosive environments.

[0079] Strong adaptability: Through complex curvature propagation path modeling, it can be widely used in pressure measurement of flat plates, spheres, cylinders and irregular containers.

[0080] High precision and high reliability: Through the superposition analysis of multiple reflection and transmission signals, combined with dynamic calibration technology, it is possible to maintain measurement accuracy under changing environmental conditions.

[0081] Strong versatility: The system design has a high degree of modularity and can be expanded to meet the measurement needs of different types of containers and adapt to a variety of operating parameters.

[0082] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A pressure measurement system for arbitrary curvature containers based on acoustic impedance analysis, characterized in that: It includes a measuring component, a power supply unit, a control unit, a signal source, and a data processing unit; wherein the measuring component includes at least one transmitting end ultrasonic transducer, at least one receiving end ultrasonic transducer, and an external sensor; The transmitting end ultrasonic transducer is used to generate an ultrasonic signal and transmit the ultrasonic signal to the inner surface of the container to be tested at a preset incident angle; The receiving end ultrasonic transducer is used to receive the ultrasonic signal attenuated after being reflected and transmitted through the inner and outer surfaces of the container to be tested; The external sensor is used to obtain external parameters of the container to be tested; The power supply unit is used to provide power to the system; The control unit is used to drive the signal source to provide an excitation signal to the transmitting end ultrasonic transducer and adjust the working parameters of the measuring component; The data processing unit is used to receive ultrasonic signals, perform acoustic impedance analysis on the container to be tested according to the interface reflection and transmission model, the sound wave attenuation model and the complex curvature propagation path model, extract the reflection coefficient and the amplitude attenuation characteristics, and calculate the internal pressure value or the external pressure value of the container to be tested according to the ideal gas state equation in combination with the calibration data and the external parameters of the container to be tested, so as to obtain the pressure measurement result of the container to be tested.

2. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis according to claim 1, characterized in that: The system further comprises a data output unit and a calibration component, and the measurement component further comprises a signal conditioning unit; The data output unit is used to output the pressure measurement result of the container to be tested; The calibration component is used to collect calibration data and correct the pressure measurement result of the container to be tested according to the external parameters of the container to be tested; The signal conditioning unit is used to condition the ultrasonic signal; The signal conditioning unit includes an ultrasonic transducer impedance matching circuit at the receiving end, an ultrasonic transducer signal amplifying circuit at the receiving end, an ultrasonic transducer voltage follower at the receiving end, and an ultrasonic transducer impedance matching circuit and an ultrasonic transducer equivalent circuit at the transmitting end.

3. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis according to claim 1, characterized in that: The incident angle The following conditions are met: ； in, , , They are the sound speeds of the gas inside the container to be tested, the material of the container to be tested, and the gas outside the container to be tested, respectively.

4. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis as claimed in claim 3, characterized in that: In the data processing unit, the reflection coefficient is calculated by the following formula: ； ； in, , are the reflection coefficients of the inner and outer surfaces of the container to be tested, respectively; are the acoustic impedances of the inside of the container to be tested, the material of the container to be tested, and the outside of the container to be tested, respectively; The amplitude attenuation characteristic is the amplitude at the receiving end during measurement. The amplitude of the receiving end during calibration The ratio is calculated by the following formula: ； in, , are respectively the reflection coefficients of the inner and outer surfaces of the container to be measured during measurement; , are respectively the reflection coefficients of the inner and outer surfaces of the container to be measured during calibration; is the total number of reflections on the inner surface of the container to be tested; is the total number of reflections on the outer surface of the container to be tested.

5. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis according to claim 4, characterized in that: The total number of reflections on the inner surface of the container to be tested is solved by the following formula: ； ； ； ； in, The ultrasonic signal The path length of the propagation in the wall of the container to be tested during the first reflection, for Projection distance projected onto the outer surface of the container to be tested; It is the shortest distance between two points on the surface of the ultrasonic transducer at the transmitting end and the ultrasonic transducer at the receiving end during measurement, that is, the total projection distance of the ultrasonic signal; is the total propagation path length of the ultrasonic signal; For the The curvature of the inner surface of the container to be tested during the second reflection; For the The curvature of the outer surface of the container to be tested during the second reflection; is the total number of reflections of the ultrasonic signal; is the incident angle of the ultrasonic signal.

6. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis according to claim 5, characterized in that: The internal pressure value of the container to be tested is calculated by the following formula: ； in, is the internal pressure value of the container to be tested; is the ideal gas constant; The amplitude of the receiving end is used for calibration; is the amplitude at the receiving end during measurement; , , , , They are the molar mass of the gas inside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, and the temperature during measurement; , are the density and sound velocity of the container material to be tested respectively; , , , , , are the molar mass, sound velocity, pressure during calibration, temperature during calibration, pressure during measurement and temperature during measurement of the gas outside the container to be measured; is the total number of reflections on the inner surface of the container to be tested, is the total number of reflections on the outer surface of the container to be tested.

7. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis according to claim 5, characterized in that: The external pressure value of the container to be tested is calculated by the following formula: ； in, is the external pressure value of the container to be tested; is the ideal gas constant; The amplitude of the receiving end is used for calibration; is the amplitude at the receiving end during measurement; , , , , They are the molar mass of the gas inside the container to be measured, the speed of sound, the pressure during calibration, the temperature during calibration, and the temperature during measurement; , are the density and sound velocity of the container material to be tested respectively; , , , , , are the molar mass, sound velocity, pressure during calibration, temperature during calibration, pressure during measurement and temperature during measurement of the gas outside the container to be measured; is the total number of reflections on the inner surface of the container to be tested, is the total number of reflections on the outer surface of the container to be tested.

8. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis according to any one of claims 6 or 7, characterized in that: The measuring assembly includes a plurality of groups of ultrasonic transducers, each group of ultrasonic transducers includes at least one transmitting end ultrasonic transducer and at least one receiving end ultrasonic transducer; The internal pressure value or external pressure value of the container to be tested is calculated by the following formula: ； in, is the internal pressure value or external pressure value of the container to be tested; For the An internal pressure value or an external pressure value of the container to be tested measured by a group of ultrasonic transducers; For the The weight coefficient of a group of ultrasonic transducers.

9. The arbitrary curvature container pressure measurement system based on acoustic impedance analysis according to claim 8, characterized in that: The weight coefficient is calculated by the following formula: ； in, Indicates The curvature of the ultrasonic signal reflection path of the ultrasonic transducer group, Indicates The thickness uniformity of the container wall through which the transducer reflection path passes, Indicates Group transducer reflection path length; Indicates Comprehensive performance parameters of the group transducer.

10. A method for measuring pressure of a container with arbitrary curvature based on acoustic impedance analysis, characterized in that: The pressure measurement system for a container with arbitrary curvature based on acoustic impedance analysis as claimed in any one of claims 1 to 9 comprises: Installing a transmitting end ultrasonic transducer and a receiving end ultrasonic transducer on the outer surface of the container to be tested; Collecting calibration data using a calibration component; The driving signal source excites the transmitting end ultrasonic transducer to emit an ultrasonic signal. The ultrasonic signal is propagated through the medium and collected by the receiving end ultrasonic transducer, and then transmitted to the data processing unit through the signal conditioning unit. Calculating the internal pressure value or the external pressure value of the container to be tested by the data processing unit to obtain the pressure measurement result of the container to be tested; The pressure measurement result is outputted through a data output unit.

Images