Icing detection device and method of detection

Abstract

The application relates to an icing detection device and a detection method. The device comprises at least two ultrasonic transducers for emitting ultrasonic signals to a target object and receiving echo signals of the ultrasonic signals; the center frequencies of the ultrasonic signals emitted by the ultrasonic transducers are different; a delay element is arranged on the side of the ultrasonic transducer close to the target object and connected with the ultrasonic transducer, and is used for delaying the time of the ultrasonic signals reaching the target object. The echo signal data corresponding to the ultrasonic transducer with a higher frequency can be selected to calculate the thickness for a thinner ice layer, and the echo signal data corresponding to the ultrasonic transducer with a lower frequency can be selected to calculate the thickness for a thicker ice layer. The device can meet the detection precision requirement of measuring thin ice layers and thick ice layers at the same time, and expands the icing thickness detection range.

Description

Technical Field

[0001] This application relates to the field of ultrasonic detection technology, and in particular to an icing detection device and detection method. Background Technology

[0002] Under icing weather conditions, transportation vehicles such as aircraft and ships, power transmission lines and towers, and exposed pipelines are prone to ice accumulation. Icing on critical components of aircraft and ships can lead to system failures and increase transportation hazards. Icing on power transmission lines and towers can cause line faults, breaks, and even electric shock accidents. Therefore, it is necessary to detect the thickness of ice accumulation in order to assess risks in a timely manner and prevent accidents.

[0003] With the development of ultrasonic detection technology, ultrasonic sensors have been increasingly used in the field of ice detection, detecting the thickness of ice by emitting ultrasonic waves and receiving the echoes. However, current ice detection devices mostly use ultrasonic sensors with a single center frequency, which makes it difficult to simultaneously meet the detection accuracy requirements of both thin and thick ice layers, and their adaptability to detection ranges with large ice thicknesses is poor. Summary of the Invention

[0004] Therefore, it is necessary to provide an icing detection device and method that can extend the detection range of icing thickness to address the aforementioned technical problems.

[0005] Firstly, this application provides an icing detection device. The device includes:

[0006] At least two ultrasonic transducers are used to transmit ultrasonic signals to a target object and receive echo signals of the ultrasonic signals; the center frequencies of the ultrasonic signals transmitted by each ultrasonic transducer are different.

[0007] A delay element is disposed on the side of the ultrasonic transducer close to the target object and connected to the ultrasonic transducer, for delaying the time it takes for the ultrasonic signal to reach the target object.

[0008] In one embodiment, the device further includes a signal processing unit connected to each of the ultrasonic transducers, for acquiring echo signals corresponding to each of the ultrasonic transducers, and determining the thickness of the target object based on the echo signals corresponding to each of the ultrasonic transducers.

[0009] In one embodiment, the echo signal corresponding to the ultrasonic transducer includes a first echo signal and a second echo signal. The first echo signal is used to characterize the echo signal generated at a first interface between the delay element and the target object, and the second echo signal is used to characterize the echo signal generated at a second interface between the target object and other media. The signal processing unit is further used to:

[0010] The comparison results are obtained by comparing the second echo signals corresponding to each of the ultrasonic transducers.

[0011] The target ultrasonic transducer among the ultrasonic transducers is determined based on the comparison results.

[0012] The thickness of the target object is determined by combining the first echo signal and the second echo signal corresponding to the target ultrasonic transducer.

[0013] In one embodiment, the device further includes:

[0014] A temperature acquisition element, one end of which is flush with the end face of the delay element away from the ultrasonic transducer, is used to acquire the temperature of the target object, and the temperature of the target object is used to correct the sound wave transmission speed corresponding to the target object.

[0015] In one embodiment, the device further includes a housing, in which both the ultrasonic transducer and the delay element are disposed, and a first opening is provided at one end of the housing near the delay element, through which the delay element extends.

[0016] In one embodiment, the delay element includes a top end face connected to the ultrasonic transducer, a bottom end face away from the ultrasonic transducer, and an outer peripheral wall connecting the top end face and the bottom end face. The outer peripheral wall includes a first outer peripheral wall connected to the top end face and a second outer peripheral wall connected to the bottom end face. The first outer peripheral wall is connected to the inner sidewall of the housing, and the second outer peripheral wall is connected to the outer surface of the icing body so that the bottom end face is flush with the outer surface of the icing body.

[0017] In one embodiment, the material of the delay element is the same as the material of the outer surface of the icing body.

[0018] In one embodiment, the ultrasonic transducer includes a backing layer, a piezoelectric layer, and an electrode layer, wherein the backing layer, the piezoelectric layer, and the electrode layer are stacked sequentially in the direction from the ultrasonic transducer to the delay element; the ultrasonic transducer also includes a matching layer, which is adapted to a through mounting notch on the electrode layer.

[0019] In one embodiment, the ultrasonic transducer further includes a cryogenic protective sleeve, the piezoelectric layer and the backing layer are disposed inside the cryogenic protective sleeve, and the cryogenic protective sleeve has an opening on the side near the delay element, the opening being opposite to the matching layer.

[0020] Secondly, this application also provides a method for detecting icing. The method includes:

[0021] The echo signals corresponding to each ultrasonic transducer are acquired; the center frequencies of the ultrasonic signals emitted by each ultrasonic transducer are different.

[0022] The thickness of the target object is determined based on the echo signals corresponding to each of the ultrasonic transducers.

[0023] The aforementioned icing detection device and method include at least two ultrasonic transducers and a delay element. Each ultrasonic transducer emits an ultrasonic signal with a different center frequency. The delay element is positioned on the side of the ultrasonic transducer closest to the target object and connected to the transducer, used to delay the arrival time of the ultrasonic signal at the target object. This application integrates at least two ultrasonic transducers with different center frequencies into the icing detection device. The higher-frequency transducer is used to measure thin ice layers, while the lower-frequency transducer is used to detect thick ice layers. This avoids the need to place ultrasonic sensors of different frequencies at the same location, saving space and enabling wide-scale measurement. When this icing detection device detects ice thickness, for thinner ice layers, the echo signal data corresponding to the higher-frequency ultrasonic transducer can be selected for thickness calculation; for thicker ice layers, the echo signal data corresponding to the lower-frequency ultrasonic transducer can be selected for thickness calculation. This simultaneously meets the detection accuracy requirements for both thin and thick ice layers, expanding the icing thickness detection range. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an icing detection device in one embodiment;

[0025] Figure 2 This is a schematic diagram of the icing detection device in another embodiment;

[0026] Figure 3 This is a schematic diagram of the interface in which an ultrasonic pulse wave propagates within a multilayer medium, as shown in one embodiment.

[0027] Figure 4 This is a schematic diagram of the icing detection device in another embodiment;

[0028] Figure 5 This is a schematic diagram of the icing detection device in another embodiment;

[0029] Figure 6 This is a top view of an icing detection device in one embodiment;

[0030] Figure 7 This is a flowchart illustrating an icing detection method in one embodiment;

[0031] 100. Ultrasonic transducer; 101. First ultrasonic transducer; 102. Second ultrasonic transducer; 110. Backing layer; 111. Piezoelectric layer; 112. Electrode layer; 113. Matching layer; 114. Mounting notch; 115. Tab; 116. Low-temperature protective sleeve; 117. Mounting groove; 118. Fixing element; 119. Sealing element; 200. Delay element; 210. Top end face; 220. Bottom end face; 230. 231. Outer peripheral wall; 232. Second outer peripheral wall; 2321. Threaded interface; 300. Signal processing component; 310. Signal line; 320. Ground wire; 400. Temperature acquisition component; 410. Ceramic sleeve; 420. Thermocouple; 500. Housing; 510. First opening; 520. Through hole; 530. Second opening; 540. Cover plate; 600. Ice layer; 700. Skin; 710. Threaded through groove. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0036] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0038] In the aerospace field, aircraft icing remains one of the main threats to aviation safety. Ultrasonic detection technology is increasingly being applied to icing detection, providing a reference for the activation of anti-icing and de-icing systems. Currently, sensors used for icing detection in the anti-icing and de-icing field typically employ piezoelectric materials with a single center frequency. However, when using a single piezoelectric-based ultrasonic sensor for icing detection, it is difficult to simultaneously meet the detection accuracy requirements for measuring both thin and thick ice layers.

[0039] To expand the range of ice thickness detection, this application provides an ice detection device, which includes at least two ultrasonic transducers. Each ultrasonic transducer generates an ultrasonic signal with a different center frequency. That is, at least two ultrasonic transducers that can generate ultrasonic signals with different center frequencies are integrated in the ice detection device. The higher center frequency can be used to detect thinner ice layers in the ice accumulation, while the lower center frequency meets the detection accuracy requirements for both thin and thick ice layers, thereby expanding the range of ice thickness detection.

[0040] In one embodiment, such as Figure 1 As shown, an icing detection device is provided, the device comprising:

[0041] At least two ultrasonic transducers 100 are used to transmit ultrasonic signals to a target object and receive echo signals of the ultrasonic signals, wherein the center frequency of the ultrasonic signals transmitted by each ultrasonic transducer 100 is different.

[0042] The delay element 200 is disposed on the side of the ultrasonic transducer 100 close to the target object and connected to the ultrasonic transducer 100, and is used to delay the time for the ultrasonic signal to reach the target object.

[0043] The target object refers to the object on which the icing detection device is used to detect the thickness. The target object can be the ice layer 600 on the outer surface of transportation vehicles such as aircraft and ships, power equipment such as power transmission lines and towers, and pipes exposed outdoors.

[0044] Figure 1 An icing detection device is illustrated, comprising a first ultrasonic transducer 101 and a second ultrasonic transducer 102. The center frequency of the ultrasonic pulse signal emitted by the first ultrasonic transducer 101 may be lower than the center frequency of the ultrasonic pulse signal emitted by the second ultrasonic transducer 102. The first ultrasonic transducer 101 can be used to detect a thicker ice layer 600 in the ice accumulation, and the second ultrasonic transducer 102 can be used to detect a thinner ice layer 600 in the ice accumulation.

[0045] In this embodiment, the delay element 200 is disposed on the side of the ultrasonic transducer 100 near the target object and connected to the ultrasonic transducer 100 to delay the time it takes for the ultrasonic signal to reach the target object. When the icing detection device performs icing detection, the end face of the delay element 200 away from the ultrasonic transducer 100 contacts the ice layer 600. For each ultrasonic transducer 100, the transducer 100 generates an ultrasonic signal towards the ice layer 600. Due to the presence of the delay element 200, the ultrasonic signal travels through the delay element 200 for a certain period before reaching the interface between the delay element 200 and the ice layer 600 and generating a first echo. The ultrasonic signal continues to travel through the ice layer 600 for a certain period before reaching the interface between the ice layer 600 and other media and generating a second echo. By delaying the time it takes for the ultrasonic signal to reach the target object through the delay element 200, the ultrasonic transducer 100 can receive two echo signals generated from the same ultrasonic signal it emits. Therefore, by combining the two echo signals, the thickness of the ice layer 600 can be determined, reducing the detection error of the ice layer 600 thickness.

[0046] The aforementioned icing detection device includes at least two ultrasonic transducers 100 and a delay element 200. Each ultrasonic transducer 100 emits an ultrasonic signal with a different center frequency. The delay element 200 is positioned on the side of the ultrasonic transducer 100 closest to the target object and connected to the ultrasonic transducer 100, used to delay the arrival time of the ultrasonic signal at the target object. In this embodiment, at least two ultrasonic transducers 100 with different center frequencies are built into the icing detection device. The higher-frequency ultrasonic transducer 100 is used to measure thin ice layers 600, and the lower-frequency ultrasonic transducer 100 is used to detect thick ice layers 600. This avoids the need to place ultrasonic sensors of different frequencies at the same location, saving space while also enabling wide-scale measurement. When the icing detection device detects the thickness of ice, for thinner ice layers 600, the echo signal data corresponding to the ultrasonic transducer 100 at a higher frequency can be selected for thickness calculation, and for thicker ice layers 600, the echo signal data corresponding to the ultrasonic transducer 100 at a lower frequency can be selected for thickness calculation. This can simultaneously meet the detection accuracy requirements for measuring both thin and thick ice layers 600 and expand the icing thickness detection range.

[0047] In one embodiment, based on Figure 1 Please refer to the embodiments shown. Figure 2 The icing detection device also includes:

[0048] The signal processing unit 300 is connected to each ultrasonic transducer 100 respectively, and is used to acquire the echo signal corresponding to each ultrasonic transducer 100 respectively, and determine the thickness of the target object based on the echo signal corresponding to each ultrasonic transducer 100 respectively.

[0049] In one possible implementation, for each ultrasonic transducer 100, the echo signal corresponding to the ultrasonic transducer 100 includes a first echo signal and a second echo signal generated from the ultrasonic pulse signal emitted by the ultrasonic transducer 100. The first echo signal is used to characterize the echo signal generated at a first interface between the delay member 200 and the target object, and the second echo signal is used to characterize the echo signal generated at a second interface between the target object and other media.

[0050] It should be noted that the other media are related to the assembly position of the icing detection device. For example, in this embodiment, the icing detection device can be fixedly installed on the inner surface of the icing body, with the end face of the delay member 200 away from the ultrasonic transducer 100 extending from the inner surface and flush with the outer surface. The icing body refers to aircraft, ships, or other transport vehicles whose outer surface will freeze in low-temperature environments. Figure 3As shown, the skin 700 is a thin-walled metal alloy or composite material component that wraps around the aircraft frame structure. The skin 700 has a cavity for installing an icing detection device. The end face of the delay member 200 away from the ultrasonic transducer 100 extends from the inner surface of the skin 700 and is flush with the outer surface. The interface between the delay member 200 and the ice layer 600 is the first interface, and the interface between the ice layer 600 and the air is the second interface.

[0051] When an ultrasonic pulse wave passes through the interface of two media with different acoustic impedances, it will produce transmission and reflection phenomena. Based on the theory of ultrasonic wave transmission in multi-layer media, the thickness of the ice layer 600 can be quickly calculated by the transit time of the pulse wave in the medium and the sound wave transmission speed in the ice layer 600.

[0052] Specifically, the signal processing unit 300 is also used to: compare the second echo signals corresponding to each ultrasonic transducer 100 to obtain a comparison result; determine the target ultrasonic transducer 100 among the ultrasonic transducers 100 based on the comparison result; and determine the thickness of the target object by combining the first echo signal and the second echo signal corresponding to the target ultrasonic transducer 100.

[0053] In this embodiment, the signal processing unit 300 compares the second echo signals corresponding to each ultrasonic transducer 100, determines the ultrasonic transducer 100 corresponding to the second echo signal with the strongest signal intensity as the target transducer, and then combines the first echo signal and the second echo signal corresponding to the target ultrasonic transducer 100 to determine the thickness of the target object.

[0054] For example, if the intensity of the second echo signal corresponding to the first ultrasonic transducer 101 is greater than the intensity of the second echo signal corresponding to the second ultrasonic transducer 102, the transit time of the ultrasonic wave in the ice layer 600 is determined by the time difference between the first transducer receiving the corresponding first echo signal and the second echo signal. The thickness of the ice layer 600 can be quickly calculated by using the transit time and the sound wave propagation speed in the ice layer 600. If the intensity of the second echo signal corresponding to the first ultrasonic transducer 101 is less than the intensity of the second echo signal corresponding to the second ultrasonic transducer 102, the transit time of the ultrasonic wave in the ice layer 600 is determined by the time difference between the second transducer receiving the corresponding first echo signal and the second echo signal. The thickness of the ice layer 600 can be quickly calculated by using the transit time and the sound wave propagation speed in the ice layer 600.

[0055] In one embodiment, such as Figure 4 As shown, the icing detection device also includes a temperature acquisition element 400, one end of which is flush with the end face of the delay element 200 away from the ultrasonic transducer 100. The temperature acquisition element 400 is used to acquire the temperature of the target object in order to correct the corresponding sound wave transmission speed of the target object.

[0056] In this embodiment, one end of the temperature acquisition element 400 is flush with the end face of the delay element 200 away from the ultrasonic transducer 100, extends out of the housing 500 and penetrates the outer surface of the icing body, thereby allowing one end of the temperature acquisition element 400 to directly contact the target object, resulting in more accurate temperature data. The signal processing element 300 is connected to the temperature acquisition element 400 via a signal line 310 to acquire the temperature data from the temperature acquisition element 400, and to correct the sound wave propagation speed based on the temperature data.

[0057] In one implementation, a channel is provided through the delay element 200, and the end of the temperature acquisition element 400 near the ice layer is inserted into the channel. The temperature acquisition element can be fixed to the inner wall of the channel using epoxy sealant.

[0058] Specifically, the channel extending through the delay element 200 facilitates the installation of the temperature acquisition element 400 and the delay element 200, while also helping to ensure the consistency between the position of the ice layer 600 measured by the temperature acquisition element 400 and the position of the ice layer 600 detected by the ultrasonic wave. This ensures the reliability of determining the actual propagation speed of the ultrasonic wave in the ice layer 600 based on its temperature. Furthermore, with the temperature acquisition element 400 extending through the channel, the delay element 200 provides stable support and protection for it.

[0059] Since the propagation speed of sound waves within ice is affected by temperature, the inability to update the wave velocity changes in a timely manner will further lead to problems such as increased errors in ice thickness measurement. Therefore, when measuring ice thickness, it is also necessary to consider the changes in longitudinal wave velocity caused by density, and to make the ice thickness measurement results more accurate through sound velocity correction.

[0060] In one implementation, the embodiments of this application pre-control the ice density by adjusting the number of air bubbles in the clear ice to obtain a fitting relationship between density and sound velocity. Then, the fitting relationship between density and sound velocity is corrected by introducing a gradient of sound velocity change with temperature in the non-porous ice layer, thereby obtaining the correspondence between sound velocity in clear ice and its temperature and density. Similarly, the correspondence between sound velocity in frost ice and its temperature and density can be obtained:

[0061] ;

[0062] ;

[0063] In the formula, Cg represents the speed of sound inside the clear ice. T represents the density of clear ice, T represents the temperature, and Cr represents the speed of sound within frost / ice. This indicates the density of frost and ice.

[0064] The density of clear ice and the density of frost ice can be determined by the ultrasonic attenuation coefficient. For example, when the ice density decreases, the attenuation coefficient within the ice increases. The fitting formula between the ultrasonic attenuation coefficient and the density of clear ice in this embodiment is as follows:

[0065] ;

[0066] In the formula, ρ0 = 890 kg / m 3 , ρ I = 900 kg / m 3 A = 0.046 and B = 3.256 are equation coefficients; α is the ultrasonic attenuation coefficient, which includes absorption attenuation and scattering attenuation caused by pores.

[0067] As ice density decreases, the ice attenuation coefficient increases. In this embodiment, an attenuation coefficient-ice density curve is pre-fitted, and the frost-ice density ρ is calculated using the ultrasonic attenuation coefficient. r The fitting formula for the ultrasonic attenuation coefficient and frost density is:

[0068] ;

[0069] In the formula, a0 = 971.45, a1 = − 460.56, and a2 = 274.31 are the coefficients of the equation.

[0070] The following embodiments will further illustrate the structure of the icing detection device provided in this application.

[0071] In one embodiment, such as Figure 5 As shown, the icing detection device also includes a housing 500, an ultrasonic transducer 100, a delay element 200 and a temperature acquisition element 400, all of which are disposed inside the housing 500. The housing 500 has a first opening 510 at one end near the delay element 200, through which the delay element 200 and the temperature acquisition element 400 extend.

[0072] The housing 500 can be cylindrical in shape and is made of stainless steel. A through hole 520 is provided on the side wall of the end of the housing 500 away from the delay element 200. The signal processing element 300 is located outside the housing 500. The signal line 310 of the signal processing element 300 passes through the through hole 520 and is connected to each ultrasonic transducer 100 and temperature acquisition element 400 respectively. The ground line 320 of the signal processing element 300 passes through the through hole 520 and is connected to the housing 500.

[0073] In one possible implementation, the housing 500 has a second opening 530 at one end away from the delay member 200, and the housing 500 has a cover plate 540 for closing the second opening 530.

[0074] In one embodiment, please refer to [link / reference]. Figure 5 The delay member 200 in this application embodiment includes a top end face 210 connected to the ultrasonic transducer 100, a bottom end face 220 away from the ultrasonic transducer 100, and an outer peripheral wall 230 connecting the top end face 210 and the bottom end face 220. The outer peripheral wall 230 of the delay member 200 includes a first outer peripheral wall 231 connected to the top end face 210 and a second outer peripheral wall 232 connected to the bottom end face 220. The first outer peripheral wall 231 is connected to the inner side wall of the housing 500, and the second outer peripheral wall 232 is connected to the outer surface of the icing body after installation.

[0075] The delay element 200 in this embodiment can be a delay block. The first outer peripheral wall 231 of the delay block is connected to the housing 500, and the second outer peripheral wall 232 extends out of the housing 500, so that when the icing detection device is installed on the icing body, the second outer peripheral wall 232 of the delay block can penetrate the inner surface of the icing body and be flush with the outer surface.

[0076] For example, the first outer peripheral wall 231 of the delay block is detachably connected to the housing 500 so that the delay element 200 can be replaced in a timely manner when unevenness develops on its surface that contacts the ice layer 600 due to prolonged use. Specifically, the detachable connection between the delay block and the housing 500 includes, but is not limited to, a threaded connection, and the threaded connection can be coated with sealant, which can be an anaerobic adhesive, to enhance the connection strength and thus ensure a tight connection between the delay block and the housing 500.

[0077] For example, the second outer peripheral wall 232 of the delay block is provided with a threaded interface 2321, and the inner surface of the aircraft skin 700 is pre-formed with a threaded groove 710 extending to the outer surface. The threaded interface 2321 can be adapted to the threaded groove 710. Specifically, the threaded groove 710 is provided on the outer surface of the area of ​​the icing body that is susceptible to icing. The icing body may have a cavity pre-formed inside to accommodate the icing detection device. The threaded groove 710 is opposite to and communicates with the cavity. During installation, the icing detection device is stably installed inside the icing body through the threaded engagement of the threaded interface 2321 and the threaded groove 710, so that the bottom end face 220 of the delay block is flush with the outer surface of the icing body. When the outer surface of the icing body is covered with a protective skin 700, an outlet opposite to and communicating with the threaded groove 710 can be opened on the skin 700 so that the bottom end face 220 of the delay block can be flush with the outer surface of the skin 700.

[0078] In this embodiment, since the bottom end face 220 of the delay element 200 is flush with the outer surface of the ice-forming body, the bottom end face 220 of the delay element 200 is always in the same low-temperature environment as the ice-forming body. This allows the bottom end face 220 of the delay element 200 to form an ice layer 600 that is consistent with the outer surface of the ice-forming body. When ultrasonic waves are transmitted through the ice layer 600 on the delay element 200, it is equivalent to transmitting them within the ice layer 600 on the outer surface of the ice-forming body. This reduces interference from air or other media between the delay element 200 and the ice layer 600, thereby improving the accuracy of the final obtained ice layer 600 thickness. Furthermore, the threaded engagement between the threaded interface 2321 and the threaded through groove 710 facilitates quick and easy installation of the icing detection device on the ice-forming body and helps ensure a tight connection between the icing detection device and the ice-forming body, thus guaranteeing the stability and reliability of the icing detection device during use.

[0079] In one embodiment, the material of the delay element 200 is the same as the material of the outer surface of the icing body.

[0080] In this embodiment, the delay element 200 is made of the same material as the outer surface of the icing body, or the same material as the protective layer on the outer surface of the icing body, to ensure the consistency between the ice layer 600 formed on the bottom end face 220 of the delay element 200 and the ice layer 600 formed on the outer surface of the icing body or the outer surface of the skin 700. This ensures that when ultrasonic waves are transmitted in the ice layer 600 on the delay element 200, it is equivalent to the transmission within the ice layer 600 on the outer surface of the icing body, thereby ensuring the accuracy of ultrasonic detection and the accuracy of the final obtained thickness of the ice layer 600.

[0081] In one embodiment, please refer to [link / reference]. Figure 5 The temperature acquisition unit 400 includes a ceramic sleeve 410 and a thermocouple 420. The thermocouple 420 is disposed inside the ceramic sleeve 410. The thermocouple 420 transmits the acquired temperature data to the signal processing unit 300 through the signal line 310.

[0082] Thermocouple 420 is used to sense the temperature of ice layer 600 after it comes into contact with the outer surface of the icing body. Ceramic sheath 410 provides good low-temperature resistance and corrosion protection for thermocouple 420, and also reduces the influence of the external environment other than ice layer 600 on thermocouple 420, thereby reducing heat transfer error and improving measurement accuracy.

[0083] In one embodiment, please refer to [link / reference]. Figure 5The ultrasonic transducer 100 includes a backing layer 110, a piezoelectric layer 111, and an electrode layer 112, which are stacked sequentially in the direction from the ultrasonic transducer 100 to the delay element 200. The ultrasonic transducer 100 also includes a matching layer 113, which is adapted to the mounting notch 114 that penetrates the electrode layer 112.

[0084] Specifically, the ultrasonic transducer 100 has a multi-layer structure including a backing layer 110, a piezoelectric layer 111, an electrode layer 112, and a matching layer 113. An installation notch 114 is provided through the electrode layer 112, and the matching layer 113 can be engaged with the installation notch 114. The tabs 115 of the electrode layer 112 extend towards the side closest to the housing 500. The matching layer 113 is used to change the acoustic impedance of the ultrasonic wave, resulting in higher propagation efficiency and better stability and sensitivity of the detection signal. The piezoelectric layer 111 can use a PZT-5H piezoelectric wafer. PZT-5H piezoelectric wafer is a common piezoelectric ceramic material. Its name comes from its main components: lead (Pb), zirconium (Zr), and titanium (Ti). In other words, the PZT-5H piezoelectric wafer is a ceramic material composed of zirconium titanate crystals. The piezoelectric layer 111 converts mechanical vibrations into electrical signals through the piezoelectric effect. The center frequency of the piezoelectric wafers in different ultrasonic transducers 100 is different. The backing layer 110 provides stable support for the signal line 310 and isolates it from environmental noise to ensure smooth transmission of the echo signal. The backing layer 110 is also a conductive layer. The matching layer 113 is disposed within the mounting notch 114 of the annular electrode layer 112, which facilitates the quick installation of the matching layer 113 and the annular electrode layer 112, thereby improving the ease of assembly and reducing the space occupied by the ultrasonic transducer 100, thus reducing the volume of the housing 500 and saving materials and production costs.

[0085] The ultrasonic transducer 100 also includes a cryogenic protective sleeve 116. The outer peripheral wall 230 of the cryogenic protective sleeve 116, near the housing 500, can be bonded to the inner peripheral wall of the housing 500 with epoxy sealant. The other side of the outer peripheral wall 230 of the cryogenic protective sleeve 116 can be bonded to other cryogenic protective sleeves 116 of the ultrasonic transducer 100 or temperature acquisition components 400 with epoxy sealant. The piezoelectric layer 111 and the backing layer 110 are disposed inside the cryogenic protective sleeve 116. The cryogenic protective sleeve 116 has an opening on the side near the delay component 200, which is opposite to the matching layer 113. Since the icing body operates at low temperatures, the icing detection device installed inside it may be damaged by temperature changes, and the transmission of the echo signal may also be interfered with. Therefore, the cryogenic protective sleeve 116 is provided to protect the ultrasonic transducer 100 used for transmitting the echo signal from low temperatures.

[0086] Furthermore, the low-temperature protective sleeve 116 includes a polytetrafluoroethylene (PTFE) protective sleeve. Since PTFE has excellent low-temperature resistance, insulation, and strength, it can provide good low-temperature protection for the ultrasonic transducer 100 while also providing good mechanical support for the ultrasonic transducer 100. In addition, the PTFE protective sleeve is easy to process and easy to cut and shape, and is suitable for the production of low-temperature protective sleeves 116 of various shapes and sizes.

[0087] Furthermore, a mounting groove 117 is provided on the side of the backing layer 110 away from the piezoelectric layer 111, and one end of the signal line 310 of the signal processing unit 300 extending into the housing 500 is fixed in the mounting groove 117 by a fastener 118.

[0088] The mounting groove 117 is located in the middle of the side of the backing layer 110 away from the delay member 200, so that after the signal line 310 is fixed in the mounting groove 117 by the fastener 118, it can be led out from the through hole 520 through a shorter path, thereby reducing the length of the transmission path, reducing signal loss during transmission, improving signal transmission quality, and thus ensuring the accuracy of calculating the thickness of the ice layer 600 based on the time difference of the received echo signal and the propagation speed of the ultrasonic wave in the ice layer 600.

[0089] Furthermore, the fastener 118 includes conductive adhesive, which fills the mounting groove 117.

[0090] Conductive adhesive is a gel-like material containing conductive particles and a special adhesive with conductive properties. It has excellent conductivity and adhesion.

[0091] Specifically, the signal line 310 is installed in the mounting groove 117, and the mounting groove 117 is filled with conductive adhesive. After the conductive adhesive dries, the signal line 310 is fixed in the mounting groove 117. The signal processing unit 300 includes a pulse signal transceiver module, which can be a signal RF connector. Since both the backing layer 110 and the conductive adhesive are conductive, the signal RF connector can apply a pulse voltage to the ultrasonic transducer 100 during operation. The transducer, which has both positive and negative piezoelectric effects, generates ultrasonic pulse waves through vibration, and when subjected to stress compression, alternating charges are generated on its surface to receive echo signals, which are then transmitted to the signal RF connector via the signal line 310.

[0092] In one embodiment, the icing detection device can be a dual-frequency icing detection sensor, comprising a high-frequency ultrasonic transducer and a low-frequency ultrasonic transducer. The high-frequency and low-frequency ultrasonic transducers are semi-cylindrical and symmetrically distributed along the central axis of the housing. Each of the high-frequency and low-frequency ultrasonic transducers contains a semi-cylindrical piezoelectric ceramic with a different center frequency, along with its corresponding backing layer, annular electrode, and matching layer. The backing layer and piezoelectric ceramic are protected by a polytetrafluoroethylene (PTFE) sleeve. A thermocouple is placed through a ceramic sleeve through a delay block, positioned closest to the bottom measuring contact surface, and at the center of the icing detection device. The high-frequency and low-frequency ultrasonic transducers are encapsulated within a cover plate and a stainless steel housing. Please refer to [reference needed]. Figure 6 The icing detection device also includes a seal 119, which fills the gaps within the housing. Filling these gaps with the seal 119 helps prevent moisture, humidity, or dust from entering the housing, thereby protecting the ultrasonic transducer inside from corrosion or contamination. It also enhances the shock resistance of the ultrasonic icing detection device. The seal can be epoxy sealant.

[0093] Since a single-center-frequency icing detection sensor cannot simultaneously meet the requirements for measuring both thin and thick ice layers, this application provides a dual-frequency icing detection sensor to expand the icing thickness detection range. The dual-frequency icing detection sensor incorporates two ultrasonic transducers with different center frequencies: a high-frequency transducer for measuring thin ice layers and a low-frequency transducer for detecting thick ice layers. Ice thickness varies at different locations on an aircraft wing. Placing two sensors at the same location on the wing would occupy too much space. This application's dual-frequency sensor, combining two piezoelectric elements with different center frequencies, effectively places two sensors with different center frequencies at the same point, saving space while achieving wide-scale measurement. Furthermore, the dual-frequency icing detection sensor can also be used for online measurement of surface ice density, small-scale surface roughness of ice layers, and ice debonding identification on aircraft surfaces.

[0094] A thermocouple temperature sensor is placed between two ultrasonic transducers to facilitate temperature and density correction for the ultrasonic transducers at different frequencies on the left and right sides. When using a single piezoelectric-based ultrasonic sensor for ice detection, the propagation speed of sound waves within the ice is affected by temperature, which further increases the error in ice thickness measurement. Therefore, this application also integrates a thermocouple temperature sensor into the ice detection sensor, thereby solving the problem that a single piezoelectric-based ultrasonic sensor cannot detect and update the temperature in a timely manner. Existing research shows that the longitudinal wave velocity in non-porous ice layers is affected by temperature, increasing by 2.812 m / s for every degree Celsius decrease in temperature. The density is corrected by introducing a gradient of sound velocity with temperature change within the non-porous ice layer. Since the magnitude of the longitudinal wave velocity within the ice layer needs to be corrected using ambient temperature and ice porosity, and then the ice thickness is calculated based on the ultrasonic longitudinal wave velocity and sound wave transit time, timely updating of the wave velocity improves measurement accuracy. By encapsulating the data within a single sensor, the temperature at the measurement point can be acquired while avoiding the problems of occupying more space and the misalignment between the temperature measurement location and the acoustic detection location, which are common with separate temperature sensors. Therefore, the dual-frequency icing detection sensor saves space, enables wide-scale measurements, and achieves the goal of measuring temperature and other parameters such as thickness at the same point.

[0095] The thermocouple is placed at the bottom of the delay block, primarily to bring it close to the object being measured. The thermocouple connection is achieved through ceramic tubing as shown in the diagram. The outer ring of the delay block features a threaded interface. The upper part is easily installed into the stainless steel housing, while the lower part can be inserted into the skin during actual measurement, shifting the sensor probe position from the inner surface of the skin to close to its outer surface. This allows the sensor to be as close as possible to the ice layer being measured. During measurement, the installation is as follows... Figure 4 As shown, while reducing near-surface measurement errors, it can also enhance the strength of the detection signal.

[0096] This sensor features a wide measurement range, high accuracy, convenient installation, and easy processing. During installation, a ring electrode is first adhered to a gold-plated piezoelectric layer. The ring structure of the electrode reduces the influence of the center on sound propagation. A matching layer is located at the center of the ring electrode, used to bridge the acoustic impedance difference between the piezoelectric material and the measured medium. A backing layer is placed on the piezoelectric layer, with a hole at the center of the cylindrical backing layer. The entire backing layer has good conductivity; wires are placed in the hole and fixed with conductive adhesive for easy processing. The impedance of the backing layer is adjusted by adjusting the material ratio, which can be used to absorb ultrasonic vibrations. Then, a polytetrafluoroethylene (PTFE) protective sleeve is installed around the entire structure, made of rigid insulating material. A cover plate seals the top of the stainless steel housing. The shielding housing is also made of stainless steel, with openings on the layers for wiring. Epoxy sealant is filled inside the housing to fix the multi-layer structure. The signal lines are soldered to the highly conductive backing layer, and the ground wire is connected to the housing. The two ultrasonic signals and the thermocouple temperature signal are connected to the signal acquisition unit through the openings in the housing for subsequent processing. The above describes the overall structure of the dual-frequency ultrasonic icing detection sensor. This dual-frequency icing detection sensor achieves wide-scale measurement, has higher accuracy in measuring ice thickness, and is resistant to low temperatures. It is also relatively convenient to process and install.

[0097] Based on the same inventive concept, this application also provides an icing detection method applied to the aforementioned icing detection device. The solution provided by this method is similar to the solution described in the aforementioned device; therefore, the specific limitations in one or more icing detection method embodiments provided below can be found in the limitations of the icing detection device described above, and will not be repeated here.

[0098] In one embodiment, such as Figure 7 As shown, an icing detection method is provided, which can be applied to... Figure 5 Taking the icing detection device in the middle as an example, the following steps are included:

[0099] Step 702: Obtain the echo signal corresponding to each ultrasonic transducer; the center frequency of the ultrasonic signal emitted by each ultrasonic transducer is different.

[0100] Step 704: Determine the thickness of the target object based on the echo signals corresponding to each of the ultrasonic transducers.

[0101] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0102] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0103] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An icing detection device, characterized in that, The device includes: At least two ultrasonic transducers are used to transmit ultrasonic signals to a target object and receive echo signals of the ultrasonic signals; the center frequencies of the ultrasonic signals transmitted by each ultrasonic transducer are different. A delay element is disposed on the side of the ultrasonic transducer close to the target object and connected to the ultrasonic transducer, for delaying the time it takes for the ultrasonic signal to reach the target object.

2. The apparatus according to claim 1, characterized in that, The device further includes: A signal processing unit, connected to each of the ultrasonic transducers, is used to acquire the echo signal corresponding to each of the ultrasonic transducers and determine the thickness of the target object based on the echo signal corresponding to each of the ultrasonic transducers.

3. The apparatus according to claim 2, characterized in that, The echo signal corresponding to the ultrasonic transducer includes a first echo signal and a second echo signal. The first echo signal is used to characterize the echo signal generated at a first interface between the delay element and the target object, and the second echo signal is used to characterize the echo signal generated at a second interface between the target object and other media. The signal processing unit is further used for: The comparison results are obtained by comparing the second echo signals corresponding to each of the ultrasonic transducers. The target ultrasonic transducer among the ultrasonic transducers is determined based on the comparison results. The thickness of the target object is determined by combining the first echo signal and the second echo signal corresponding to the target ultrasonic transducer.

4. The apparatus according to claim 1, characterized in that, The device further includes: A temperature acquisition element, one end of which is flush with the end face of the delay element away from the ultrasonic transducer, is used to acquire the temperature of the target object, and the temperature of the target object is used to correct the sound wave transmission speed corresponding to the target object.

5. The apparatus according to claim 1, characterized in that, The device also includes a housing, in which the ultrasonic transducer and the delay element are both disposed, and a first opening is provided at one end of the housing near the delay element, through which the delay element extends.

6. The apparatus according to claim 5, characterized in that, The delay element includes a top end face connected to the ultrasonic transducer, a bottom end face away from the ultrasonic transducer, and an outer peripheral wall connecting the top end face and the bottom end face. The outer peripheral wall includes a first outer peripheral wall connected to the top end face and a second outer peripheral wall connected to the bottom end face. The first outer peripheral wall is connected to the inner sidewall of the housing, and the second outer peripheral wall is connected to the outer surface of the icing body so that the bottom end face is flush with the outer surface of the icing body.

7. The apparatus according to claim 1, characterized in that, The material of the delay element is the same as the material of the outer surface of the icing body.

8. The apparatus according to claim 1, characterized in that, The ultrasonic transducer includes a backing layer, a piezoelectric layer, and an electrode layer, which are stacked sequentially in the direction from the ultrasonic transducer to the delay element. The ultrasonic transducer also includes a matching layer that is adapted to a through mounting notch on the electrode layer.

9. The apparatus according to claim 8, characterized in that, The ultrasonic transducer also includes a low-temperature protective sleeve, the piezoelectric layer and the backing layer are disposed inside the low-temperature protective sleeve, and the low-temperature protective sleeve has an opening on the side near the delay element, the opening being opposite to the matching layer.

10. A method for detecting icing, characterized in that, The method, applied to the icing detection device according to any one of claims 1 to 9, comprises: The echo signals corresponding to each ultrasonic transducer are acquired; the center frequencies of the ultrasonic signals emitted by each ultrasonic transducer are different. The thickness of the target object is determined based on the echo signals corresponding to each of the ultrasonic transducers.

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