Fluid characteristic detection system and detection method based on photonic crystal

Abstract

The invention discloses a fluid characteristic detection system and detection method based on a photonic crystal, and belongs to the technical field of fluid detection. The system comprises a signal generation device, a signal amplification device, a photonic crystal fluid characteristic detection device, a signal acquisition and processing module and an upper computer which are connected in sequence. Based on the system, the characteristic that efficient regulation and control of elastic waves are achieved through photonic crystal band gaps and defects is utilized, defect units are introduced into periodic photonic crystals, high-sensitivity and high-resolution detection of multiple parameters such as density, viscosity and salinity of fluid to be detected is achieved, and the system has the advantages of being wide in frequency regulation range, rich in data dimension and the like; meanwhile, a photonic crystal fluid characteristic detection device in the system has replaceability, the number of detection channels and photonic crystal structures can be selected in a targeted mode according to detection requirements, the detection efficiency is improved, and interference is reduced. The detection system and method disclosed by the invention can be used for detecting various characteristics of liquid and gas, are also applicable to gas-liquid mixed media, can be further integrated with other photoelectric and micro-fluidic technologies to form a multifunctional sensor, and are widely applied to the fields of biomedical treatment, environmental monitoring, chemical production and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid detection, and in particular, to a fluid property detection system and a detection method based on phononic crystals. Background Art

[0002] The detection of fluid properties plays a crucial role in many fields. It is not only the basis of scientific research but also a key link in multiple fields such as industrial production, environmental monitoring, and medical diagnosis. By accurately measuring fluid properties such as concentration, viscosity, and salinity, the technological process can be optimized, product quality can be ensured, the environment can be protected, and public health can be improved.

[0003] Currently, the methods for fluid property detection vary according to the physical quantity to be measured. For example, for concentration detection, spectroscopic methods and conductivity methods are suitable for rapid on-site detection, and titration methods are used for high-precision laboratory analysis; for viscosity detection, rotational viscometers are highly versatile, and vibrating viscometers are suitable for industrial on-line monitoring; for salinity detection, conductivity methods are the most commonly used, and titration methods are the gold standard. Among them, although some methods have a certain degree of universality in the detection principles of different properties, there are also some deficiencies. For example, spectroscopic methods and conductivity methods can be used for measuring the concentration and salinity of fluids, and have advantages such as high sensitivity and wide application range, but have certain requirements for the transparency and color of samples; although conductivity methods have low requirements for equipment and are easy to operate, they rely heavily on the electrochemical properties of samples. In addition, the above methods have poor compatibility for detecting the properties of multiple substances, and the same method cannot be used for detecting the properties of different substances, especially for gas-liquid mixed media formed by gases and liquids.

[0004] The present invention provides a fluid property detection system and a detection method based on phononic crystals, which solve the deficiencies of common detection hardware and methods. By modulating elastic waves with phononic crystals, multi-parameter measurements of fluid density, viscosity, salinity, sound velocity, etc. are realized, and it has advantages such as richer data dimensions and higher detection efficiency. Summary of the Invention

[0005] The purpose of the present invention is to overcome the many deficiencies existing in the existing fluid property detection solutions, and provide a detection system and a detection method with high sensitivity, wide frequency range, high detection efficiency, and rich data dimensions.

[0006] The present invention is realized through the following technical solutions:

[0007] In a first aspect, a fluid property detection system based on phononic crystals is provided, mainly including a signal generating device 1, a signal amplifying device 2, a phononic crystal fluid property detection device 3, a signal acquisition and processing module 4, and a host computer 5;

[0008] The signal generating device 1 is used to generate an electrical signal for exciting elastic waves;

[0009] The signal amplification device 2 is used to amplify the electrical signal generated by the signal generation device 1;

[0010] The phonon crystal fluid property detection device 3 is used to receive the electrical signal output by the signal amplification device 2, generate an elastic wave for fluid property detection, and further convert the elastic wave carrying the detection information into an electrical signal for output;

[0011] The signal acquisition and processing module 4 is used to acquire the output signal of the phonon crystal fluid property detection device 3 and perform signal processing on it;

[0012] The host computer 5 is used to analyze the signal output by the signal acquisition and processing module 4 and present the detection result.

[0013] In a second aspect, a method for detecting fluid properties based on a phonon crystal is provided, and the main steps include: sample placement, signal generation, sample detection, signal output, data acquisition and processing, feature extraction, and result output.

[0014] The differences and beneficial effects of the present invention from the existing related technologies are as follows:

[0015] The invention "Photonic Crystal Liquid Concentration Sensor Based on Surface Plasmon Resonance" (publication numbers CN116242806A, CN219475396U) discloses an optical-based liquid concentration sensor. Compared with it, the fluid property detection system and method based on a phonon crystal provided by the present invention focus on the system rather than the sensor in the specific detection hardware, focus on the acoustic-based detection method rather than the optical-based detection method in the specific detection principle, and focus on liquids, gases, and gas-liquid mixed media in the specific detection object, rather than simply liquids;

[0016] Similarly, the invention "Gas Density Sensing System Based on Fiber Optic FP Resonator and Fiber Bragg Grating" (publication number CN118896878A) discloses an optical-based gas density sensing system, and its core components include a light source module, a barometric pressure and temperature sensor module, and a gas density detection module. This system calculates the temperature of the gas by measuring the resonance frequency drift of the fiber optic FP resonator structure, calculates the pressure of the gas by the change value of the center wavelength of the reflection spectrum of the fiber Bragg grating structure, and finally realizes the measurement of the gas density; it is found by comparison that this invention is different from the present invention both in terms of the detection system hardware and the detection method, and the present invention can detect multiple fluids simultaneously, including gases, liquids, and their mixed media, and has stronger novelty.

[0017] The technical solution disclosed by the present invention can replace the fluid detection device according to the detection requirements, selectively choose the number of detection channels and the phononic crystal structure, improve the detection efficiency and reduce interference. At the same time, this technical solution can detect various characteristics of liquids, gases and gas-liquid mixed media, and can further form a multi-functional sensor by integrating with other optoelectronic and microfluidic technologies, which is widely used in the fields of biomedicine, environmental monitoring, chemical production, etc. Description of the Drawings

[0018] Figure 1 Schematic diagram of a fluid property detection system based on phononic crystals shown in an embodiment of the present invention;

[0019] Figure 2 Flowchart of a fluid property detection method based on phononic crystals shown in an embodiment of the present invention (for one sample detection structure and one reference detection structure);

[0020] Figure 3 Flowchart of a fluid property detection method based on phononic crystals shown in an embodiment of the present invention (for multiple sample detection structures and multiple reference detection structures);

[0021] Figure 4 Flowchart of a fluid property detection method based on phononic crystals shown in an embodiment of the present invention (for one sample detection structure);

[0022] Figure 5 Flowchart of a fluid property detection method based on phononic crystals shown in an embodiment of the present invention (for multiple sample detection structures);

[0023] Figure 6 Phononic crystal fluid property detection device for alcohol concentration detection shown in an embodiment of the present invention;

[0024] Figure 7 Energy band structure of unit cell structures 3-5 on a phononic crystal fluid property detection device for alcohol concentration detection shown in an embodiment of the present invention;

[0025] Figure 8 Energy band structure of unit cell structures 3-6 on a phononic crystal fluid property detection device for alcohol concentration detection shown in an embodiment of the present invention;

[0026] Figure 9 Sound pressure intensity distribution diagram of elastic waves on a phononic crystal fluid property detection device for alcohol concentration detection shown in an embodiment of the present invention;

[0027] Figure 10 Frequency information presented by different concentrations of alcohol on a phononic crystal fluid property detection device shown in an embodiment of the present invention;

[0028] Figure 11 This is a graph showing the relationship between alcohol concentration and frequency illustrated in the embodiments of the present invention.

[0029] In the figure: 1. Signal generator; 2. Signal amplification device; 3. Phononic crystal fluid property detection device; 4. Signal acquisition and processing module; 5. Host computer; 3-1. Transducer; 3-2. Two-dimensional phononic crystal structure; 3-3. Cylindrical deep hole for constructing phononic crystal; 3-4. Cylindrical deep hole for constructing phononic crystal defect; 3-5. Phononic crystal unit cell structure without defect; 3-6. Phononic crystal unit cell structure including defect characteristics. Detailed implementation manners

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. Generally, the components of the embodiments of the present application described and illustrated in the drawings here can be arranged and designed in various different configurations. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0031] It should be noted that all the defects existing in the above prior art solutions are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of the present application below for the above problems should be the contributions made by the inventor to the present application during the invention creation process, and should not be understood as the technical content known to those skilled in the art.

[0032] In response to the technical problems pointed out in the background art, the embodiments provided by the present invention are as follows:

[0033] Embodiment 1

[0034] The present invention provides a fluid property detection system based on phononic crystals, as shown in Figure 1 , including a signal generation device 1, a signal amplification device 2, a phononic crystal fluid property detection device 3, a signal acquisition and processing module 4, and a host computer 5;

[0035] The signal generation device 1 is used to generate an electrical signal for exciting elastic waves;

[0036] Preferably, the signal generation device 1 has a signal programmable control function, including any signal generator, an embedded system device with corresponding functions, a single-chip microcomputer circuit with corresponding functions, a programmable logic array chip circuit with corresponding functions, and an integrated chip with corresponding functions that can generate specific signals;

[0037] The signal amplification device 2 is used to amplify the electrical signal generated by the signal generation device 1;

[0038] Preferably, the signal amplification device 2 has configurability and can adjust important parameters such as input and output voltage range, output power, gain, bandwidth, impedance, common-mode rejection ratio, noise, etc. to meet the requirements of input and output signals;

[0039] The phonon crystal fluid property detection device 3 is used to receive the electrical signal output by the signal amplification device 2, generate elastic waves for fluid property detection, and further convert the elastic waves carrying detection information into electrical signals for output;

[0040] Preferably, the phonon crystal fluid property detection device 3 includes a transducer device and a phonon crystal structure; among them, the transducer device has the ability to mutually convert electrical signals and acoustic signals, and the phonon crystal structure has a band structure. When elastic waves propagate in it, due to the action of its internal structure, they are blocked from propagating within a certain frequency range (bandgap), while they can propagate without loss within other frequency ranges (passband);

[0041] Preferably, the phonon crystal structure of the phonon crystal fluid property detection device 3 is jointly composed of a sample detection structure and a reference detection structure, and the common-mode interference such as temperature and vibration is eliminated by forming a differential structure to improve the detection accuracy and sensitivity, or it is solely composed of a sample detection structure;

[0042] Preferably, the sample detection structure and the reference detection structure are separately composed of an electro / acoustic transducer, a phonon crystal, and an acoustic / electric transducer, or are integrally formed;

[0043] Preferably, the electro / acoustic transducer is one of a piezoelectric structure, a flexoelectric structure, an ultrasonic transmitter, and a speaker; the phonon crystal is an acoustic metamaterial; the acoustic / electric transducer is one of a piezoelectric structure, a flexoelectric structure, an ultrasonic receiver, and a microphone;

[0044] Preferably, the piezoelectric structure is a Rayleigh wave excitation structure, or a Love wave excitation structure, or a surface shear wave excitation structure, or a Lamb wave excitation structure, or a bulk acoustic wave excitation structure; the flexoelectric structure is a sandwich structure formed by sequentially stacking a conductive material, a flexoelectric material, and a conductive material, or a composite layered structure formed by alternately stacking a conductive material and a flexoelectric material multiple times;

[0045] Preferably, the electro / acoustic transducer, the phonon crystal, and the acoustic / electric transducer are arranged on the same substrate;

[0046] Preferably, the phonon crystal is a one-dimensional phonon crystal, a two-dimensional phonon crystal, or a three-dimensional phonon crystal;

[0047] Preferably, the phononic crystal has a two-component, three-component or more-component structure;

[0048] Preferably, the phononic crystal is composed of a single structure repeating periodically, or several different structures repeating periodically, and its defect is formed by removing one unit, or several units, or one row, or several rows from the periodically repeating structure;

[0049] Preferably, the phononic crystal fluid property detection device 3 is a movable and replaceable component, and the number of sample detection structures and reference detection structures inside it is one or more. The number of detection channels and the phononic crystal structure can be selected according to actual needs;

[0050] The signal acquisition and processing module 4 is used to acquire the output signal of the phononic crystal fluid property detection device 3 and perform signal processing on it;

[0051] Preferably, the signal acquisition and processing module 4 includes a low-noise amplifier circuit, a filter circuit, a mixer circuit, an analog / digital conversion circuit, and a differential signal processing circuit, which can perform functions such as amplifying, filtering, mixing, sampling, and differential processing on the input electrical signal;

[0052] The host computer 5 is used to analyze the signal output by the signal acquisition and processing module 4 and present the detection result;

[0053] Preferably, the host computer 5 is a computer installed with a data analysis algorithm or program, or an embedded system with corresponding analysis functions, and can display the analyzed information.

[0054] Embodiment 2

[0055] The present invention provides a method for detecting the fluid property based on a phononic crystal. By using the differential technique to collect and process the acoustic signals of the sample detection structure and the reference detection structure, the detection of the property of the fluid to be measured in a sample detection structure is realized, mainly including steps such as placing the sample, generating the signal, detecting the sample, outputting the signal, data acquisition and processing, feature extraction, and outputting the result. The process is as Figure 2 shown as follows:

[0056] S1: Place the fluid to be measured and the calibrated fluid in the sample detection structure and the reference detection structure respectively;

[0057] S2: Start the signal generating device 1 to generate an electrical signal that excites elastic waves; Preferably, the electrical signal is a sine signal, a triangular wave signal, a sawtooth wave signal, or a square wave signal with adjustable power, amplitude, frequency, phase, and offset;

[0058] S3: The electrical signal is amplified by the signal amplification device 2 and then acts on the phonon crystal fluid property detection device 3;

[0059] S4: The electro-acoustic transducer in the phonon crystal fluid property detection device 3 converts the amplified electrical signal into an elastic wave with a specific frequency;

[0060] S5: The elastic wave propagates along the phonon crystal defect in the sample detection structure and the reference detection structure. After passing through the fluid to be measured and the calibrated fluid, it further propagates to the acoustic / electro transducer;

[0061] S6: The acoustic / electro transducer converts the above two paths of elastic waves into electrical signal 1 and electrical signal 2;

[0062] S7: The signal acquisition and processing module 4 acquires, amplifies, filters, and differentially processes the above two paths of electrical signals, and transmits the processed signals to the host computer 5 for analysis;

[0063] S8: The host computer 5 analyzes the power, amplitude, frequency, phase, and their offsets of the electrical signal, and presents the analysis results to complete the detection.

[0064] Embodiment 3

[0065] The present invention provides a method for detecting fluid properties based on a phonon crystal. By using differential technology to collect and process the acoustic signals of the sample detection structure and the reference detection structure, the detection of the properties of the fluid to be measured in multiple sample detection structures is realized, mainly including steps such as placing samples, generating signals, detecting samples, outputting signals, data collection and processing, feature extraction, and outputting results. The process is as Figure 3 shown as follows:

[0066] S1: Place the fluid to be measured and the calibrated fluid in the sample detection structure and the reference detection structure respectively;

[0067] S2: Start the signal generating device 1 to generate an electrical signal for exciting an elastic wave; preferably, the electrical signal is a sine signal, a triangular wave signal, a sawtooth wave signal, or a square wave signal with adjustable power, amplitude, frequency, phase, and offset;

[0068] S3: The electrical signal is amplified by the signal amplification device 2 and then acts on the phonon crystal fluid property detection device 3;

[0069] S4: The electro-acoustic transducer in the phonon crystal fluid property detection device 3 converts the amplified electrical signal into an elastic wave with a specific frequency;

[0070] S5: The elastic wave propagates along the phonon crystal defect in both the n sample detection structures and the n reference detection structures simultaneously. After passing through the fluid under test and the calibrated fluid, it further propagates to the acoustic / electrical transducer.

[0071] S6: The acoustic / electrical transducer converts the above 2×n elastic waves into 2×n electrical signals.

[0072] S7: The signal acquisition and processing module 4 acquires, amplifies, and filters the above electrical signals, performs differential processing on the electrical signals in the same group (for example, electrical signal 1-1 and electrical signal 1-2 are in a group), and transmits the processed signals to the host computer 5 for analysis.

[0073] S8: The host computer 5 analyzes the power, amplitude, frequency, phase, and their offsets of the electrical signals, presents the analysis results, and completes the detection.

[0074] Embodiment 4

[0075] The present invention provides a method for detecting fluid characteristics based on a phonon crystal. The system only acquires and processes the output acoustic signals of one sample detection structure to realize the detection of the characteristics of the fluid under test. The process is as Figure 4 shown below:

[0076] S1: Place the fluid under test in the sample detection structure.

[0077] S2: Start the signal generating device 1 to generate an electrical signal for exciting the elastic wave; preferably, the electrical signal is a sine wave signal, a triangular wave signal, a sawtooth wave signal, or a square wave signal with adjustable power, amplitude, frequency, phase, and offset.

[0078] S3: The electrical signal is amplified by the signal amplifying device 2 and then acts on the phonon crystal fluid characteristic detection device 3.

[0079] S4: The electro / acoustic transducer in the phonon crystal fluid characteristic detection device 3 converts the amplified electrical signal into an elastic wave with a specific frequency.

[0080] S5: The elastic wave propagates along the phonon crystal defect in the sample detection structure. After passing through the fluid under test, it further propagates to the acoustic / electrical transducer.

[0081] S6: The acoustic / electrical transducer converts the above elastic wave into an electrical signal.

[0082] S7: The signal acquisition and processing module 4 acquires, amplifies, and filters the above electrical signals, and transmits the processed signals to the host computer 5 for analysis.

[0083] S8: The host computer 5 analyzes the power, amplitude, frequency, phase, and their offsets of the electrical signals, presents the analysis results, and completes the detection.

[0084] Example 5

[0085] The present invention provides a method for detecting fluid characteristics based on a phononic crystal. The system collects and processes the output acoustic signals of multiple sample detection structures to realize the detection of characteristics of multiple fluids or multiple characteristics of a fluid to be measured. The process is as Figure 5 shown below:

[0086] S1: Place the fluid to be measured in the sample detection structure;

[0087] S2: Start the signal generating device 1 to generate an electrical signal that excites elastic waves; preferably, the electrical signal is a sine signal, triangular wave signal, sawtooth wave signal, or square wave signal with adjustable power, amplitude, frequency, phase, and offset;

[0088] S3: The electrical signal is amplified by the signal amplifying device 2 and then acts on the phononic crystal fluid characteristic detection device 3;

[0089] S4: The electro-acoustic transducer in the phononic crystal fluid characteristic detection device 3 converts the amplified electrical signal into an elastic wave with a specific frequency;

[0090] S5: The elastic wave propagates along the phononic crystal defect in n sample detection structures. After passing through the fluid to be measured, it further propagates to the acoustic-electric transducer;

[0091] S6: The acoustic-electric transducer converts the above n elastic waves into n electrical signals;

[0092] S7: The signal acquisition and processing module 4 collects, amplifies, and filters the above electrical signals, and transmits the processed signals to the host computer 5 for analysis;

[0093] S8: The host computer 5 analyzes the power, amplitude, frequency, phase, and offset of the electrical signal, and presents the analysis result to complete the detection.

[0094] Example 6

[0095] Based on the present invention, a system and method for detecting fluid characteristics based on a phononic crystal are provided. The system uses the phononic crystal fluid characteristic detection device 3 as shown in Figure 6 to realize the detection of alcohol with different concentrations:

[0096] Preferably, the phononic crystal fluid characteristic detection device 3 is composed of a transducer 3-1 and a two-dimensional phononic crystal structure 3-2. The transducers 3-1 on the left and right sides have the same specifications, and they are connected to the middle two-dimensional phononic crystal structure 3-2 through a coupling agent. All three parts are replaceable and removable movable components;

[0097] Preferably, the transducer 3-1 is made of PZT piezoelectric material and gold electrodes in a sandwich form (the upper, middle, and lower layers are gold, PZT, and gold respectively). After receiving a periodic electrical signal, the entire structure has the ability to generate a plane wave with the same frequency and propagating along the x-direction, and also has the ability to convert elastic waves into electrical signals;

[0098] Preferably, the main structure of the two-dimensional phononic crystal structure 3-2 is stainless steel, with its length, width, and thickness being 13×a, 6×a, and a / 14 respectively (where a = 28 mm), and its surface is jointly composed of the periodic structures 3-3 and 3-4;

[0099] Preferably, the structure 3-3 is a cylindrical hole with a radius r1 = 9 mm and a depth h = 1 mm. Its upper surface is on the same horizontal plane as the surface of the main structure of the two-dimensional phononic crystal structure 3-2, and its internal filling is ultrapure water;

[0100] Preferably, the distance between the centers of the circles of the structure 3-3 is a;

[0101] Preferably, the structure 3-4 is a cylindrical hole with a radius r2 = 3 mm and a depth h = 1 mm. Its upper surface is on the same horizontal plane as the surface of the main structure of the two-dimensional phononic crystal structure 3-2;

[0102] Preferably, the structure 3-4 is composed of two parts: an external annular structure and an internal circular structure. Among them, the outer diameter of the external annular structure is r2 = 3 mm, the inner diameter is r3 = 2 mm, the radius of the internal circular structure is r3 = 2 mm, and the depths of both structures are h = 1 mm;

[0103] Preferably, the external annular structure is a solid and soft polymer, and the internal circular structure is liquid alcohol with the concentration to be detected;

[0104] Preferably, the distance between the centers of the circles of the structure 3-4 is a, and the distance between its centers of the circles and those of the structure 3-3 is 0.5×a;

[0105] Preferably, the densities of the stainless steel, ultrapure water, and polymer are 7780 kg / m 3 、1000 kg / m 3 、960 kg / m 3 , and their longitudinal sound velocities are 5825 m / s, 1490 m / s, and 1000 m / s respectively;

[0106] Preferably, the unit cell structure 3-5 formed by the structure 3-3 and the external stainless steel has a band structure as shown in Figure 7 . It can be seen from the figure that this structure has a complete phononic crystal band gap in the range of 17.79 kHz to 48.92 kHz;

[0107] Preferably, when the internal filling density of the structure 3-4 is 790 kg / m 3 , and the liquid alcohol with a longitudinal sound velocity of 1156 m / s is filled, the unit cell structure 3-6 formed by the structures 3-3, 3-4 and the external stainless steel has a band structure as shown in Figure 8 ;

[0108] Comparing Figure 7 and Figure 8 it can be seen that a passband is added in the original complete phononic crystal band gap of the unit cell structure 3-6, and its starting frequency is about 30.69 kHz and the ending frequency is about 30.53 kHz. Within the passband, the elastic wave energy is concentrated in the defect and propagates along the positive x-axis direction, as shown in Figure 9 . In order to complete the measurement of the concentration of the alcohol to be measured, the liquid alcohol with the concentration to be measured is placed in the internal circular structure of the structure 3-4, and then the signal generating device 1, the signal amplifying device 2, the phononic crystal fluid property detecting device 3, the signal collecting and processing module 4, and the upper computer 5 are connected and started;

[0109] Preferably, the liquid alcohol with the concentration to be measured is mixed by pure alcohol and ultrapure water, and its sound velocity v 混合 and density ρ 混合 respectively satisfy v 混合 =d 酒精 ×v 酒精 +d 水 ×v 水 and ρ 混合 =d 酒精 ×ρ 酒精 +d 水 ×ρ 水 , where d 酒精 , d 水 , v 酒精 , v 水 , ρ 酒精 , ρ 水 are respectively the volume ratio of alcohol, the volume ratio of water, the sound velocity of alcohol, the sound velocity of water, the density of alcohol and the density of water;

[0110] Preferably, the signal generating device 1 is adjusted to generate a sine signal with a step size of 0.2 kHz and a frequency range of 15 kHz to 50 kHz, and the signal is output to the signal amplifying device 2;

[0111] Preferably, the power of the signal amplifying device 2 is adjusted, and the amplified electrical signal is output to the phononic crystal fluid property detecting device 3 to generate a plane wave with a pressure amplitude of 1 Pa and a phase of 0 rad;

[0112] The generated plane wave propagates in the phononic crystal fluid property detecting device 3. When the concentration d of the alcohol to be measured is detected酒精 When they are 5%, 20%, 35%, 50%, 65%, 80%, and 95% respectively, the energy band structures in the ΓX direction of the Brillouin zone are as follows Figure 10 shown. It can be seen from the figure that the passbands caused by different concentrations of alcohol are all different, and there is no overlap or mutual interference. In this regard, the relationship between frequency and concentration can be further established, as follows Figure 11 shown, and the functional relationship between concentration and frequency can be fitted by mathematical methods. Then, when measuring the alcohol with unknown concentration subsequently, the concentration information can be obtained according to the measured frequency.

[0113] The structure of the present invention is reasonable, the design is ingenious, and the detection accuracy is high. Utilizing the characteristics of phonon defect states, when the characteristics of the fluid to be measured change, its acoustic parameters change accordingly, and the acoustic resonance characteristics of the defect states also change, resulting in changes in the characteristics of the electrical signal output by the transducer, such as power, amplitude, frequency, and phase. The measurement of the characteristics of the fluid to be measured is realized by detecting the characteristics of the electrical signal, making up for the deficiencies of the prior art.

[0114] The above specific embodiments are detailed descriptions of the present invention. It cannot be determined that the specific embodiments of the present invention are only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, several simple deductions and substitutions can still be made, which should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A fluid property detection system based on phononic crystals, characterized in that: It comprises a signal generating device (1), a signal amplifying device (2), a phononic crystal fluid characteristic detecting device (3), a signal collecting and processing module (4) and a host computer (5) which are connected in sequence; The signal generating device (1) is used to generate an electrical signal for exciting elastic waves; the signal amplifying device (2) is used to amplify the electrical signal generated by the signal generating device (1), and to act the amplified signal on a phononic crystal fluid property detection device (3); the phononic crystal fluid property detection device (3) comprises a transducer device and a phononic crystal structure, wherein the transducer device has the ability to convert electrical signals and acoustic signals into each other, and the phononic crystal structure has the ability to select elastic waves of specific frequencies to pass through, and the ability to limit elastic waves to its defects; the signal acquisition and processing module (4) is used to collect, amplify, filter and other processes on the electrical signal output by the phononic crystal fluid property detection device (3), and transmit the processed signal to a host computer (5); the host computer (5) is used to analyze the received signal and present the result.

2. A fluid property detection system based on phononic crystals according to claim 1, characterized in that: The phononic crystal fluid property detection device (3) is a differential detection structure composed of a sample detection structure and a reference detection structure, or is composed of a sample detection structure alone; the sample detection structure and the reference detection structure are composed of an electric / acoustic transducer, a phononic crystal, and an acoustic / electric transducer in a separate manner or in an integrated manner.

3. A fluid property detection system based on phononic crystals according to claim 1, characterized in that: The phononic crystal fluid property detection device (3) is a movable and replaceable component, and the number of sample detection structures and the number of reference detection structures therein are one or more.

4. A fluid property detection system based on phononic crystals according to claim 2, characterized in that: The electric / acoustic transducer is one of a piezoelectric structure, a flexoelectric structure, an ultrasonic transmitter, and a loudspeaker; the phononic crystal is an acoustic metamaterial; The acoustic / electric transducer is one of a piezoelectric structure, a flexoelectric structure, an ultrasonic receiver, and a microphone.

5. A fluid property detection system based on phononic crystals according to claim 4, characterized in that: The piezoelectric structure is an elastic wave excitation structure of a surface acoustic wave device or an elastic wave excitation structure of a bulk acoustic wave device; the flexoelectric structure is a sandwich structure formed by stacking conductive material, flexoelectric material, and conductive material in sequence, or a composite layered structure formed by multiple alternating stacking of conductive material and flexoelectric material.

6. A fluid property detection system based on phononic crystals according to claim 2, characterized in that: The electric / acoustic transducer, the phononic crystal and the acoustic / electric transducer are arranged on the same substrate.

7. A fluid property detection system based on phononic crystals according to claim 2, characterized in that: The phononic crystal is a one-dimensional phononic crystal, a two-dimensional phononic crystal or a three-dimensional phononic crystal.

8. The fluid property detection system based on phononic crystal according to claim 2, characterized in that: The phononic crystal is a two-component, three-component or more-component structure.

9. A fluid property detection system based on phononic crystals according to claim 2, characterized in that: The phononic crystal is composed of a single periodic repeating structure, or of several different periodic repeating structures, and its defects are formed by removing one unit, or several units, or one row, or multiple rows from the periodic repeating structure.

10. A detection method for a fluid property detection system based on phononic crystals according to any one of claims 1 to 9, characterized in that: The acoustic method is used to detect the fluid characteristics, and the differential technology is used to collect and process the acoustic signals of the sample detection structure and the reference detection structure to realize the characteristic detection of the fluid to be tested. The specific steps are as follows: S1: placing the fluid to be tested and the calibrated fluid in the sample detection structure and the reference detection structure respectively; S2: starting the signal generating device (1) to generate an electrical signal for exciting elastic waves; S3: the electrical signal is amplified by the signal amplifying device (2) and then acts on the phononic crystal fluid property detection device 3; S4: The electric / acoustic transducer in the phononic crystal fluid property detection device (3) converts the amplified electric signal into an elastic wave with a specific frequency; S5: The elastic wave propagates along the phononic crystal defects in the sample detection structure and the reference detection structure, and after passing through the fluid to be tested and the calibrated fluid, it further propagates to the acoustic / electric transducer; S6: The acoustic / electric transducer converts the above two elastic waves into electrical signals; S7: The signal acquisition and processing module (4) acquires, amplifies, filters, and performs differential processing on the above two electrical signals, and transmits the processed signals to the host computer (5) for analysis; S8: The host computer (5) analyzes the power, amplitude, frequency, phase and offset of the electrical signal and presents the analysis results to complete the detection.

11. A detection method for a fluid property detection system based on phononic crystals according to any one of claims 1 to 9, characterized in that: The acoustic method is used to detect the fluid characteristics. The system only collects and processes the output acoustic signal of the sample detection structure to detect the characteristics of the fluid to be tested. The specific steps are as follows: S1: placing the fluid to be tested in the sample detection structure; S2: starting the signal generating device (1) to generate an electrical signal for exciting elastic waves; S3: the electrical signal is amplified by the signal amplifying device (2) and then acts on the phononic crystal fluid property detection device 3; S4: The electric / acoustic transducer in the phononic crystal fluid property detection device (3) converts the amplified electric signal into an elastic wave with a specific frequency; S5: The elastic wave propagates along the phononic crystal defects in the sample detection structure, and after passing through the fluid to be tested, it further propagates to the acoustic / electric transducer; S6: The acoustic / electric transducer converts the elastic wave into an electrical signal; S7: The signal acquisition and processing module (4) acquires, amplifies, and filters the electrical signal, and transmits the processed signal to the host computer (5) for analysis; S8: The host computer (5) analyzes the power, amplitude, frequency, phase and offset of the electrical signal and presents the analysis results to complete the detection.

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