An array type ice detector

Abstract

The present invention provides an array-type ice detector, which belongs to the field of aviation detection technology, and includes a complex impedance sensing mechanism and an embedded data processing device. The complex impedance sensing mechanism is arranged on the surface of a structure where ice detection is required, and includes a substrate, a foil electrode pair array, and a non-metallic coating. The foil electrode pair array is arranged on the top of the substrate, and includes a plurality of electrode pairs with different spatial wavelengths, which are used to collect complex impedance frequency characteristic data of different penetration depths; the non-metallic coating is arranged on the top of the foil electrode pair array; one end of the embedded data processing device is connected to the foil electrode pair array through a shielded cable, and the other end is connected to a digital bus. The embedded data processing device drives the plurality of electrode pairs to perform complex impedance frequency characteristic data measurement in sequence and receives the measurement data. The embedded data processing device identifies the state of ice, water, and ice-water mixed phases on the surface of the structure according to the measurement data and calculates the temperature, thickness, and stacking order of the ice layer and water film.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation detection, and in particular relates to an array type ice detector. Background Art

[0002] Icing is a major safety hazard for structures such as aircraft and wind turbines, and also reduces their operational efficiency. Anti-icing systems ensure the safe operation of aircraft and wind turbines, but traditional icing sensors are unable to cope with measurement tasks in the mixed phase of ice and water. Icing sensors have poor feedback capabilities on the anti-icing effect, resulting in the anti-icing system always having problems with long working hours and excessive energy consumption.

[0003] Patent application CN114476081 discloses an ice detector with stable performance. By optimizing the component structure and assembly process of the resonant tube ice sensor, the output performance of the resonant system is made more stable, achieving a good ice detection effect. The patent application principle is mature and reliable, with high ice detection accuracy, and describes the performance of the most widely used ice sensor. However, its extended probe rod is perpendicular to the wing surface. When the wing surface is undergoing anti-icing operations, it is difficult for the sensor to sense the melting of the ice layer on the wing surface, the refreezing of the water film, etc. At the same time, in the resonant principle, water accumulation causes the output frequency to decrease, while ice formation causes the output frequency to increase. In the mixed state of ice and water, the output frequency of the sensor cannot represent the actual thickness of the ice layer, and there is a risk of missed alarms.

[0004] Patent application CN101038183 discloses a fiber optic ice sensor that uses a flat-end fiber bundle to detect the reflected light intensity based on an active light source, thereby measuring the thickness of the ice layer. The invention is small in size, highly adaptable, has good electromagnetic compatibility, and is highly reliable, making it very suitable for structural ice detection. However, detection based on optical principles is difficult to identify ice layers and water films in a mixed state of ice and water, and has poor detection capabilities for anti-icing effects, and cannot guide the anti-icing system to work efficiently. Summary of the invention

[0005] In order to overcome the above-mentioned deficiencies in the prior art, the present invention provides an array-type ice detector.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] An array type ice detector, comprising:

[0008] The complex impedance sensing mechanism is arranged on the surface of the structure where ice detection is required, and comprises:

[0009] substrate;

[0010] A foil electrode pair array is disposed on the top of the substrate, comprising a plurality of electrode pairs of different spatial wavelengths for collecting complex impedance frequency characteristic data at different penetration depths;

[0011] A non-metallic coating is disposed on top of the foil electrode pair array;

[0012] as well as,

[0013] An embedded data processing device is connected to the foil electrode pair array via a shielded cable at one end and to a digital bus at the other end. The embedded data processing device drives a plurality of electrode pairs to sequentially perform complex impedance frequency characteristic data measurements and receives the measurement data. The embedded data processing device identifies the states of ice, water, and ice-water mixed phases on the surface of the structure according to the measurement data and calculates the temperature, thickness, and stacking order of the ice layer and water film.

[0014] Preferably, each of the electrode pairs adopts interdigitated electrodes, which are arranged in a cross-shaped manner.

[0015] Preferably, the penetration depth d of each electrode pair is directly related to the spatial wavelength λ, which is determined by the electrode width w and the electrode centerline spacing s. For different penetration depths, the electrode width w and the electrode centerline spacing s satisfy the following conditions:

[0016]

[0017] Where C0 is the capacitance value measured when a sufficiently thick ice layer grows directly on the surface of the electrode pair, C d C is the capacitance value measured when the distance between the ice layer and the electrode surface is equal to the penetration depth d. ∞ is the capacitance value measured when the ice layer is at infinity.

[0018] Preferably, the number of the electrode pairs is at least three, and the distance between the electrode pairs and the top surface of the non-metallic coating does not exceed one quarter of the minimum penetration depth and does not exceed 1 mm.

[0019] Preferably, the foil electrode pair array includes three electrode pairs with different spatial wavelengths, a low penetration depth electrode pair 101, a medium penetration depth electrode pair 102 and a high penetration depth electrode pair 103, the centerline spacing s of the three electrode pairs are 3.6 mm, 6.8 mm and 12.6 mm respectively, the electrode width w is 0.9 mm, 1.7 mm and 3.15 mm respectively, and the penetration depth of the high penetration depth electrode pair 103 is greater than or equal to three times the penetration depth of the low penetration depth electrode pair 101.

[0020] Preferably, the substrate and the non-metallic coating are made of polyimide or glass fiber layer materials, and the electrode pair is made of copper foil.

[0021] Preferably, the substrate further comprises a grounding layer electrode for protecting the electrode measurement environment, and the distance between the grounding layer electrode and the plurality of electrode pairs in the thickness direction is greater than 1 mm.

[0022] Preferably, the embedded data processing device comprises a complex impedance measurement circuit and an electrode pair switching circuit.

[0023] Preferably, the substrate is made of a polyimide film in combination with a polymer reinforcement sheet and a protective copper foil. The polyimide film completely wraps the polymer reinforcement sheet and the protective copper foil, and the polymer reinforcement sheet is located on top of the protective copper foil. The protective copper foil is a ground layer electrode connected to the circuit signal ground. The polymer reinforcement sheet is located below the foil electrode pair array and has a thickness of 1 mm.

[0024] Preferably, the embedded data processing device 3 collects complex impedance data through the electrode pair and calculates the capacitance C according to the RC parallel model. p And the loss tangent value D, the calculation formula is as follows,

[0025]

[0026] In the formula, Z * (ω) is the measured impedance mode, Z′(ω) is the real part of the impedance mode, Z”(ω) is the imaginary part of the impedance mode, ω is the angular frequency, θ is the phase angle, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the medium, S is the area facing the generalized capacitor plates, d is the distance between the plates, G is the equivalent conductivity of the RC parallel network, σ e is the conductivity of the medium.

[0027] The array-type ice detector provided by the present invention has the following beneficial effects:

[0028] The embedded data processing device of the present invention collects complex impedance data through a complex impedance sensing mechanism, and distinguishes the state of each electrode pair within the penetration depth according to the size of the low-frequency and high-frequency capacitance measured by each electrode pair, so as to identify the ice-water mixing state; at the same time, combined with the different penetration depths of electrode pairs with different spatial wavelengths, quantitative measurement of the ice-water mixing state can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiment of the present invention and its design scheme, the following briefly introduces the drawings required for this embodiment. The drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 is a schematic structural diagram of an array-type ice detector according to an embodiment of the present invention;

[0031] Figure 2 is a conceptual diagram of the electrode design of the array-type ice detector according to an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of a measurement data curve and a processing method of an array ice detector according to an embodiment of the present invention;

[0033] Figure 4 Schematic diagram of temperature distribution measured by an array-type ice detector according to an embodiment of the present invention;

[0034] Figure 5 It is a schematic structural diagram of an array-type ice detector according to another embodiment of the present invention.

[0035] Description of reference numerals:

[0036] 1-complex impedance sensing mechanism, 2-shielded cable, 3-embedded data processing device, 4-digital bus, 101-low penetration depth electrode pair, 102-medium penetration depth electrode pair, 103-high penetration depth electrode pair, 104-non-metallic coating, 105-substrate. DETAILED DESCRIPTION

[0037] In order to enable those skilled in the art to better understand the technical solution of the present invention and implement it, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the scope of protection of the present invention.

[0038] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the technical solutions of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] In addition, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance. In the description of the present invention, it should be noted that, unless otherwise clearly specified or limited, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. In the description of the present invention, unless otherwise specified, "plurality" means two or more, which will not be described in detail here.

[0040] Example 1

[0041] The present invention provides an array-type ice detector, which adopts an impedance ice detection method based on the relaxation polarization principle, and realizes quantitative detection of the freezing and melting states of ice layers through a complex impedance sensing mechanism 1 with multi-level spatial wavelengths and an embedded data processing device 3.

[0042] The complex impedance sensing mechanism 1 is arranged on the surface of the structure to be detected for ice, and includes a substrate 105, an array of foil electrode pairs, and a non-metallic coating 104, such as Figure 1 As shown, the foil electrode pair array is arranged on the top of the substrate 105, which includes a plurality of electrode pairs of different spatial wavelengths, each electrode pair adopts interdigitated electrodes, which are arranged in a cross-arrangement state to collect complex impedance frequency characteristic data of different penetration depths; the non-metallic coating 104 is arranged on the top of the foil electrode pair array;

[0043] One end of the embedded data processing device 3 is connected to the complex impedance sensing mechanism 1 through the shielded cable 2, and the other end is connected to the digital bus 4. The embedded data processing device 3 drives multiple electrode pairs with different spatial wavelengths to measure the complex impedance frequency characteristic data in turn and receive the measurement data. The embedded data processing device 3 identifies the state of ice, water and ice-water mixed phases on the surface of the structure according to the measurement data and calculates the temperature, thickness and stacking order of the ice layer and water film.

[0044] The detection principle of the present invention utilizes the relaxation polarization characteristics of H2O molecules. The positive and negative charge centers of water (H2O, hydrogen-oxygen bond angle 104.5°) do not overlap, and it is a polar molecule. Ice also has the same property, but the relaxation time for the inherent dipole moment of the two to turn to polarization is different, resulting in different characteristics of their relative dielectric constant changing with frequency. Based on this principle, ice and water can be distinguished and identified. At the same time, according to the relative relationship of the capacitance values ​​measured at different frequencies, the mixed state of ice and water can be identified; combined with the different penetration depths of electrode pairs with different spatial wavelengths, quantitative measurement of the mixed state of ice and water can be achieved.

[0045] The penetration depth d of each electrode pair is directly related to the spatial wavelength λ, which is determined by the electrode width w and the electrode centerline spacing s as follows: Figure 2 As shown in the figure, for different penetration depths, the electrode width w and the electrode centerline spacing s meet the following conditions:

[0046]

[0047] Where C0 is the capacitance value measured when a sufficiently thick ice layer grows directly on the surface of the electrode pair, C d C is the capacitance value measured when the distance between the ice layer and the electrode surface is equal to the penetration depth d. ∞ is the capacitance value measured when the ice layer is at infinity.

[0048] In this embodiment, the substrate 105 and the non-metallic coating 104 are made of polyimide or glass fiber material, and the electrodes are made of copper foil. The substrate 105 also includes a grounding layer electrode for protecting the electrode measurement environment; the distance between the grounding layer electrode and the plurality of electrode pairs in the thickness direction is greater than 1 mm. The number of electrode pairs is at least three, and the maximum penetration depth is greater than or equal to three times the minimum penetration depth, and the distance between the electrode pair and the top surface of the non-metallic coating 104 does not exceed one-fourth of the minimum spatial wavelength electrode pair penetration depth, and does not exceed 1 mm.

[0049] Example 2

[0050] The foil electrode pair array includes three electrode pairs with different spatial wavelengths, a low penetration depth electrode pair 101, a medium penetration depth electrode pair 102, and a high penetration depth electrode pair 103. The centerline spacing s of the three electrode pairs are 3.6 mm, 6.8 mm, and 12.6 mm, respectively, and the electrode widths w are 0.9 mm, 1.7 mm, and 3.15 mm, respectively. The length of the interdigital electrode and the number of electrode interdigits are determined by the size of the detector. Usually, the electrode length is not less than 10 mm, and the number of electrode interdigital pairs is not less than 3 pairs. The thickness of the top non-metallic film 104 is 0.2 mm.

[0051] The embedded data processing device 3 includes a complex impedance measurement circuit and an electrode pair switching circuit. After each pair of electrodes is measured, it is immediately switched to the next pair of electrodes for measurement. The time for measuring all the electrode pairs in the array is preferably controlled within 3 seconds. Each electrode adopts a sweep frequency working mode, the sweep frequency range is 0.5kHz to 200kHz, and the sweep frequency step is 0.25 on the common logarithmic coordinate axis of the frequency.

[0052] The embedded data processing device 3 collects complex impedance data through the complex impedance sensing mechanism 1 and calculates the capacitance C according to the RC parallel model. p And the loss tangent value D, the calculation formula is as follows,

[0053]

[0054] In the formula, Z * (ω) is the measured impedance mode, Z′(ω) is the real part of the impedance mode, Z”(ω) is the imaginary part of the impedance mode, ω is the angular frequency, θ is the phase angle, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the medium, S is the area facing the generalized capacitor plates, d is the distance between the plates, G is the equivalent conductivity of the RC parallel network, σ e is the conductivity of the medium.

[0055] like Figure 3 As shown, select C at 500Hz low and C at 200kHz high The threshold C0 is slightly higher than the capacitance value at 500 Hz when the electrode pair is unloaded, C1 is slightly higher than the capacitance value at 200 kHz when the electrode pair is frozen, and C2 is slightly lower than the capacitance value at 200 kHz when the electrode pair is flooded. In particular, for each pair of electrodes with different structures, the relevant thresholds are different.

[0056] The measured capacitance value and ice thickness H ICE , water film thickness H WATER The relationship between is represented by the following formula, where the polynomial coefficients are obtained by fitting the experimental data.

[0057]

[0058] Wherein, a1, a2, a3, b1, b2, b3, c1, c2, c3, d1, d2 and d3 are polynomial coefficients obtained by data fitting.

[0059] The embedded data processing device 3 estimates the ice layer temperature through the loss tangent value D. The loss tangent value D curve has a single peak characteristic within the measurement frequency range, and the peak frequency f p Characterizes the temperature of the ice layer. Figure 4 For example, the ice layer is divided into three regions according to the penetration depth of the electrode pair. The ice layer in each region is considered to be isothermal. The integral result of the ice layer temperature in the thickness direction determines f p The equivalent temperature T1 of area 1 is calculated starting from the electrode pair with the shallowest penetration depth, and then the equivalent temperature calculation result of area 1 is substituted into the calculation equation of the equivalent temperature T2 of area 2, and so on to obtain the equivalent temperature of each area.

[0060] The temperature relationship between the surface and bottom layers can be determined through equivalent temperature measurement results, thereby identifying the freezing and melting state of the ice layer. The temperature distribution curve in the direction of ice thickness is fitted and spline interpolation fitting is performed to observe the change in the temperature gradient of the ice layer.

[0061] Example 3

[0062] In this embodiment, the electrode pair is designed as a plurality of single electrodes 101-1 to 101-6, each of which is connected to the embedded data processing device 3 via shielded cables 201 to 206. The embedded data processing device 3 combines the single electrodes through relays to realize electrode pairs with different penetration depths. In this embodiment, the width w of a single electrode is 1 mm, the length of the electrode is 20 mm, and the center line spacing s of adjacent electrodes is 1 mm. When forming a low penetration depth electrode pair, 101-1, 101-3, and 101-5 are connected as one electrode, and 101-2, 101-4, and 101-6 are connected as another electrode; when forming a medium penetration depth electrode pair, 101-1 and 101-2 are connected as one electrode, 101-4 and 101-5 are connected as another electrode, and 101-3 and 101-6 are floating electrodes; when forming a high penetration depth electrode pair, 101-1 and 101-2 are connected as one electrode, 101-5 and 101-6 are connected as another electrode, and 101-3 and 101-4 are floating electrodes. In this embodiment, the measuring method of the detector is the same as that of Embodiments 1 and 2.

[0063] The array-type ice detector provided by the present invention has the following beneficial effects:

[0064] 1. Based on the relaxation polarization principle, the present invention realizes the quantitative measurement of the ice-water mixing state through electrode pairs with different penetration depths, eliminating the functional blind spots of traditional ice sensors, and is expected to greatly improve the working efficiency of the anti-icing system, which has obvious practical significance;

[0065] 2. Since the complex impedance sensing mechanism of the present invention is made of thin film material and has flexible and bendable properties, compared with the traditional rigid structure sensor, the present invention can be installed on a curved surface with a small curvature and will not cause additional air resistance like the traditional rigid protruding sensor;

[0066] 3. The detector of the present invention adopts a multi-layer thin film structure, which is easy to install and has a low weight, thereby reducing the cost of use and maintenance.

[0067] The embodiments described above are only preferred specific implementation modes of the present invention, and the protection scope of the present invention is not limited thereto. Any simple changes or equivalent replacements of the technical solutions that can be obviously obtained by any technician familiar with the field within the technical scope disclosed in the present invention belong to the protection scope of the present invention.

Claims

1. An array type ice detector, characterized in that: include: The complex impedance sensing mechanism (1) is arranged on the surface of a structure where ice detection is required, and comprises: A substrate (105); A foil electrode pair array is arranged on the top of the substrate (105), comprising a plurality of electrode pairs with different spatial wavelengths, for collecting complex impedance frequency characteristic data at different penetration depths; A non-metallic coating (104) is disposed on the top of the foil electrode pair array; as well as, An embedded data processing device (3) is connected to the foil electrode pair array at one end through a shielded cable (2) and is connected to a digital bus (4) at the other end; the embedded data processing device (3) drives a plurality of the electrode pairs to sequentially perform complex impedance frequency characteristic data measurement and receives the measurement data; the embedded data processing device (3) identifies the state of ice, water, and ice-water mixed phases on the surface of the structure based on the measurement data and calculates the temperature, thickness, and stacking order of the ice layer and water film.

2. The array ice detector according to claim 1, characterized in that: Each of the electrode pairs adopts interdigitated electrodes, which are arranged in a cross-arrangement state.

3. The array type ice detector according to claim 1, characterized in that: The penetration depth d of each electrode pair is directly related to the spatial wavelength λ, which is determined by the electrode width w and the electrode centerline spacing s. For different penetration depths, the electrode width w and the electrode centerline spacing s satisfy the following conditions: Where C0 is the capacitance value measured when a sufficiently thick ice layer grows directly on the surface of the electrode pair, C d C is the capacitance value measured when the distance between the ice layer and the electrode surface is equal to the penetration depth d. ∞ is the capacitance value measured when the ice layer is at infinity.

4. The array type ice detector according to claim 3, characterized in that: The number of the electrode pairs is at least three, and the distance between the electrode pairs and the top surface of the non-metallic coating (104) does not exceed one quarter of the minimum penetration depth and does not exceed 1 mm.

5. The array type ice detector according to claim 4, characterized in that: The foil electrode pair array comprises three electrode pairs with different spatial wavelengths, a low penetration depth electrode pair (101), a medium penetration depth electrode pair (102) and a high penetration depth electrode pair (103). The centerline spacings s of the three electrode pairs are 3.6 mm, 6.8 mm and 12.6 mm respectively, and the electrode widths w are 0.9 mm, 1.7 mm and 3.15 mm respectively. The penetration depth of the high penetration depth electrode pair (103) is greater than or equal to three times the penetration depth of the low penetration depth electrode pair (101).

6. The array-type ice detector according to claim 1, characterized in that: The substrate (105) and the non-metallic coating (104) are made of polyimide or glass fiber layer materials, and the electrode pair is made of copper foil.

7. The array ice detector according to claim 1, characterized in that: The substrate (105) also includes a grounding layer electrode for protecting the electrode measurement environment, and the distance between the grounding layer electrode and the plurality of electrode pairs in the thickness direction is greater than 1 mm.

8. The array ice detector according to claim 1, characterized in that: The embedded data processing device (3) comprises a complex impedance measurement circuit and an electrode pair switching circuit.

9. The array type ice detector according to claim 6, characterized in that: The substrate (105) is made of a polyimide film, a polymer reinforcement sheet, and a protective copper foil. The polyimide film completely wraps the polymer reinforcement sheet and the protective copper foil, and the polymer reinforcement sheet is located on the top of the protective copper foil. The protective copper foil is a grounding layer electrode connected to the circuit signal ground. The polymer reinforcement sheet is located below the foil electrode pair array and has a thickness of 1 mm.

10. The array type ice detector according to claim 1, characterized in that: The embedded data processing device (3) collects complex impedance data through the electrode pair and calculates the capacitance C according to the RC parallel model. p And the loss tangent value D, the calculation formula is as follows, In the formula, Z * (ω) is the measured impedance mode, Z′(ω) is the real part of the impedance mode, Z”(ω) is the imaginary part of the impedance mode, ω is the angular frequency, θ is the phase angle, ε0 is the vacuum dielectric constant, ε r is the relative dielectric constant of the medium, S is the area facing the generalized capacitor plates, d is the distance between the plates, G is the equivalent conductivity of the RC parallel network, σ e is the conductivity of the medium.

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