A heat and force combined deicing structure and deicing method

Abstract

The present invention provides a heat-and-force combined deicing structure and method, comprising a control unit, a main piezoelectric ceramic, a secondary piezoelectric ceramic, and a heating unit. The heating unit is disposed in an area of the deicing device susceptible to ice formation, the main piezoelectric ceramic is disposed at the resonant point of the deicing device, and the control unit and secondary piezoelectric ceramic are disposed in an area of the deicing device susceptible to ice formation. The secondary piezoelectric ceramic detects the natural frequency of the deicing device and transmits it to the control unit. The control unit transmits the natural frequency to the main piezoelectric ceramic via an excitation signal. Upon receiving the excitation signal, the main piezoelectric ceramic generates ultrasonic guided waves for deicing. The combined heat-and-force deicing method significantly reduces energy consumption and significantly increases deicing speed. By monitoring the natural frequency in real time, the excitation is always maintained in the operating mode of the current natural frequency, resulting in maximum shear deformation and the best deicing effect.

Description

Technical Field

[0001] The present invention belongs to the field of deicing, and in particular relates to a heat and force combined deicing structure and a deicing method. Background Art

[0002] In cold and humid environments, ice can form on the surfaces of structures, causing a range of serious hazards. Examples include wind turbine blades, aircraft, and power transmission cables. Currently, thermal de-icing is a relatively stable and widely used method. However, thermal de-icing often takes a long time and consumes a large amount of energy. In some applications, using thermal de-icing requires extended power outages, disrupting normal operations and resulting in ineffective de-icing. Summary of the Invention

[0003] The purpose of the present invention is to provide a heat and force combined deicing structure and deicing method, aiming to solve the problem that the existing deicing methods have poor deicing effect and affect normal operation.

[0004] The present invention is implemented as follows: a heat and force combined deicing structure includes a control unit, a main piezoelectric ceramic, a secondary piezoelectric ceramic and a heating unit. The heating unit is arranged in an area of the deiced device that is prone to ice formation. The main piezoelectric ceramic is arranged at the resonance point of the deiced device. The control unit and the secondary piezoelectric ceramic are arranged in an area of the deiced device that is not prone to ice formation. The secondary piezoelectric ceramic detects the natural frequency of the deiced device and sends it to the control unit. The control unit sends the natural frequency to the main piezoelectric ceramic through an excitation signal. After receiving the excitation signal, the main piezoelectric ceramic generates ultrasonic guided waves for deicing.

[0005] A further technical solution of the present invention is that the control unit, the main piezoelectric ceramic and the auxiliary piezoelectric ceramic are all arranged away from the heating unit.

[0006] A further technical solution of the present invention is that the power supply of the heating unit is connected to the control unit.

[0007] A further technical solution of the present invention is that the heating unit adopts an electric heating resistance wire.

[0008] Another object of the present invention is to provide a deicing method for a deicing structure combining heat and force, comprising the following steps:

[0009] Step S1: Arrange the heating units in the area of the de-icing device that is prone to ice formation. The arrangement of the heating units is based on the formula Calculate, where H n is the distance between the heating units, Q is the total power of the heating units during deicing, H is the length of the heating units to be arranged along the span direction, T is the desired surface temperature of the deicing device, and H pis the thickness of the deicing device, λ is the thermal conductivity of the deicing device, and l is the length of the heating unit to be arranged;

[0010] Step S2: placing the control unit and the secondary piezoelectric ceramic in an area that is less prone to ice formation, and placing the primary piezoelectric ceramic at the resonance point of the de-icing device;

[0011] Step S3: The auxiliary piezoelectric ceramic detects the natural frequency of the de-icing device and sends it to the control unit. The control unit sends the measured natural frequency as the excitation frequency to the main piezoelectric ceramic to generate ultrasonic guided waves, so that the de-icing device vibrates and generates shear stress, and at the same time turns on the power of the heating unit to work for heating.

[0012] A further technical solution of the present invention is: in step S1, the desired surface temperature of the de-icing device is The length of the heating unit along the extension direction needs to be arranged H = nH n , n is the total number of the heating units to be arranged along the span direction.

[0013] A further technical solution of the present invention is: in step S1, the total power of the heating unit during deicing is Q=nQ", Q" is the working power of each heating unit, Q"=H p *2*Q'l, Q' is the heat flux density.

[0014] A further technical solution of the present invention is: step S3 includes the following steps:

[0015] Step S31: In an ice-free state, the secondary piezoelectric ceramic detects the natural frequency of the de-icing device, and uses the measured natural frequency in the ice-free state as the excitation frequency and sends it to the control unit. The control unit controls the primary piezoelectric ceramic to operate at the natural frequency in the ice-free state and turns on the heating unit.

[0016] Step S32: After the main piezoelectric ceramic operates for a preset time, the auxiliary piezoelectric ceramic performs frequency detection on the de-icing device again. If the frequency is consistent with the natural frequency in the ice-free state, it is confirmed that the de-icing device is in the ice-free state. The main piezoelectric ceramic operates at the natural frequency in the ice-free state. If the frequency is inconsistent with the natural frequency in the ice-free state, it is confirmed that the de-icing device is in the ice-covered state, and the process proceeds to step S33.

[0017] Step S33: sending the new natural frequency measured by the secondary piezoelectric ceramic to the control unit, so that the operating frequency of the primary piezoelectric ceramic becomes the new natural frequency measured, and then proceeding to step S32.

[0018] A further technical solution of the present invention is that the auxiliary piezoelectric ceramic selects the natural frequency with the maximum energy from the measured natural frequencies as the excitation frequency.

[0019] The beneficial effects of the present invention are: the reasonable arrangement of the electric heating resistance wire in the structure of the present invention maximizes the energy utilization rate during the heating process, and the problem of uneven heating will not occur; the combined heat and force de-icing greatly reduces energy consumption and greatly improves the de-icing speed; by real-time monitoring of the natural frequency, the excitation is always in the working mode of the current natural frequency, the shear deformation generated is maximum, and the de-icing effect is best; the de-icing unit can be installed on the inside or outside of the structure according to actual conditions, which is easy to install and maintain, and will not damage the original operating characteristics and aerodynamic performance of the structure; when there is no ice, the system can also play an anti-icing role to ensure the safe operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic diagram of the present invention applied to a wing;

[0021] Figure 2 is a cross-sectional view of the present invention applied to a wing;

[0022] Figure 3 It is a schematic diagram of the present invention applied to a cable. DETAILED DESCRIPTION

[0023] Reference numerals: 1 - heating unit, 2 - main piezoelectric ceramic, 3 - secondary piezoelectric ceramic, 4 - wing skin, 5 - thermal insulation layer, 6 - fixed arm.

[0024] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom," "top," "inner," and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0025] The present invention provides a heat and force combined deicing structure, including a control unit, a main piezoelectric ceramic 2, a secondary piezoelectric ceramic 3 and a heating unit 1. The heating unit 1 is arranged in an area of the deicing device that is prone to ice formation, the main piezoelectric ceramic 2 is arranged at the resonance point of the deicing device, the control unit and the secondary piezoelectric ceramic 3 are arranged in an area of the deicing device that is not prone to ice formation, the secondary piezoelectric ceramic 3 detects the natural frequency of the deicing device and sends it to the control unit, the control unit sends the natural frequency to the main piezoelectric ceramic 2 through an excitation signal, and the main piezoelectric ceramic 2 generates ultrasonic guided waves for deicing after receiving the excitation signal.

[0026] Preferably, the control unit, the main piezoelectric ceramic 2 and the auxiliary piezoelectric ceramic 3 are all arranged away from the heating unit 1 .

[0027] Preferably, the power supply of the heating unit 1 is connected to the control unit.

[0028] Preferably, the heating unit 1 uses an electric heating resistance wire.

[0029] The present invention also provides a deicing method for a heat and force combined deicing structure, comprising the following steps:

[0030] Step S1: Arrange the heating units 1 in the area of the de-icing device that is prone to ice formation. The arrangement of the heating units 1 is based on the formula Calculate, where H n is the distance between the heating units 1, Q is the total power of the heating units 1 during deicing, H is the length of the heating units 1 along the span direction, T is the desired surface temperature of the deicing device, and H p is the thickness of the deicing device, λ is the thermal conductivity of the deicing device, and l is the length of the heating unit 1 to be arranged;

[0031] Step S2: placing the control unit and the auxiliary piezoelectric ceramic 3 in an area that is not prone to ice formation, and placing the main piezoelectric ceramic 2 at the resonance point of the de-icing device;

[0032] Step S3: The auxiliary piezoelectric ceramic 3 detects the natural frequency of the de-icing device and sends it to the control unit. The control unit sends the measured natural frequency as the excitation frequency to the main piezoelectric ceramic 2 to generate ultrasonic guided waves, so that the de-icing device vibrates and generates shear stress, and at the same time turns on the power of the heating unit 1 to work for heating.

[0033] Preferably, in step S1, the desired surface temperature of the de-icing device is The length of the heating unit 1 along the extension direction needs to be arranged H=nH n , n is the total number of the heating units 1 to be arranged along the span direction.

[0034] Preferably, in step S1, the total power of the heating unit 1 during deicing is Q=nQ", Q" is the working power of each heating unit 1, and Q"=H p *2*Q'l, Q' is the heat flux density.

[0035] Preferably, the step S3 comprises the following steps:

[0036] Step S31: In the ice-free state, the secondary piezoelectric ceramic 3 detects the natural frequency of the de-icing device, and uses the measured natural frequency in the ice-free state as the excitation frequency and sends it to the control unit. The control unit controls the primary piezoelectric ceramic 2 to operate at the natural frequency in the ice-free state and turns on the heating unit 1.

[0037] Step S32: After the main piezoelectric ceramic 2 operates for a preset time, the auxiliary piezoelectric ceramic 3 performs frequency detection on the deiced device again. If the frequency is consistent with the natural frequency in the ice-free state, it is confirmed that the deiced device is in the ice-free state. The main piezoelectric ceramic 2 operates at the natural frequency in the ice-free state. If the natural frequency is inconsistent with the natural frequency in the ice-free state, it is confirmed that the deiced device is in the ice-covered state, and the process proceeds to step S33.

[0038] Step S33: sending the new natural frequency measured by the auxiliary piezoelectric ceramic 3 to the control unit, so that the operating frequency of the main piezoelectric ceramic 2 becomes the new natural frequency measured, and then proceeding to step S32.

[0039] Preferably, the secondary piezoelectric ceramic 3 selects the natural frequency with the maximum energy among the measured natural frequencies as the excitation frequency.

[0040] The present invention provides a combined heat and force deicing structure and method. This combined heat and force deicing technology forms a water film on the ice layer and the surface of the structure when heated, significantly reducing the adhesion stress of the ice layer. Force is generated by ultrasonic guided waves propagating through the structure. When propagating through different media, a velocity difference is generated, which in turn creates shear stress on the ice layer and the surface of the structure, causing the ice to break and separate. Simultaneously, both heating and guided wave vibrations make it more difficult for water droplets to adhere to the surface, reducing the amount of ice formed. This combined heat and force deicing technology increases the speed of deicing and reduces the energy required and the weight of the device.

[0041] In this structure, the heating effect of the heating unit 1 is used to heat the areas prone to ice formation, thereby reducing the adhesion stress of the ice layer. The heating unit 1 is mainly arranged in key areas where the structure is prone to ice formation and the ice layer is thick. The heating unit 1 can be arranged on the surface or inside of the structure. In order to keep the surface heating temperature above 0°C and the temperature at each position uniform, it is avoided that there are areas with low heating temperature, no water film formed, or too high heating temperature, which causes energy waste and then affects the de-icing effect. In order to maximize the utilization of energy, the reasonable arrangement of the heating unit 1 is crucial. The arrangement of the heating unit 1 is determined according to the following formula:

[0042]

[0043] nH n =H (2);

[0044] nQ”=Q (3);

[0045] Q”=H p *2*Q'l (4);

[0046]

[0047] T is the desired surface temperature of the deicing device, Q' is the heat flux density, Q" is the operating power of each heating unit 1, H is the span length of the heating units 1 to be arranged, n is the total number of heating units 1 to be arranged along the span direction, Q is the total power of the heating units 1 during deicing, H n is the distance between the heating units 1, H p is the thickness of the deicing device, λ is the thermal conductivity of the deicing device, and l is the required length of the heating unit 1. The layout of the heating unit 1 can be determined based on the material properties of the structure and the environment in which it is located. Temperature T is related to the deicing rate; higher T means faster deicing. Higher T means more energy consumption. Therefore, the energy provided can be adjusted based on actual needs to control the temperature T and, therefore, the deicing rate.

[0048] Relying solely on heat treatment as a de-icing method is difficult to remove quickly and effectively. Therefore, the structure of the present invention achieves quick and effective de-icing through the combined action of force and heat. Ice layers may also form in some areas where the heating unit 1 is not arranged. In such areas, there is less ice coverage and the ice layer is thin. The use of ultrasonic guided waves can generate sufficient shear stress for effective de-icing. This arrangement can not only further reduce energy consumption, but also expand the area for effective de-icing, achieve effective de-icing of the entire structure, and better utilize the advantages of combined heat and force de-icing. By setting the main piezoelectric ceramic 2 and the auxiliary piezoelectric ceramic 3 to generate ultrasonic guided waves, the ice in the area with thin ice layer is processed by using the generated shear stress. The auxiliary piezoelectric ceramic 3 can detect the current natural frequency of the de-icing device and transmit the measured natural frequency to the main piezoelectric ceramic 2 via the control unit. The main piezoelectric ceramic 2 operates at the natural frequency measured by the auxiliary piezoelectric ceramic 3 and is positioned at the resonant point of the de-icing device. Therefore, when the main piezoelectric ceramic 2 is in operation, it resonates with the de-icing device. The resulting vibration deformation can remove thick ice layers heated by the heating unit 1, as well as thin ice layers on the surface of the structure. The auxiliary piezoelectric ceramic 3 measures multiple data points when detecting the natural frequency and selects the natural frequency with the maximum energy.

[0049] When the de-icing device is in an ice-free state, the auxiliary piezoelectric ceramic 3 will measure the natural frequency in the ice-free state and store the natural frequency in the control unit. In the ice-free state, the heating unit 1 and the main piezoelectric ceramic 2 will also operate to ensure that the temperature of the structure surface is maintained above 0°C, shake off water droplets on the surface, and achieve an anti-icing effect. When the natural frequency measured by the auxiliary piezoelectric ceramic 3 is different from the natural frequency in the ice-free state, it proves that ice has formed on the de-icing device. The newly measured natural frequency will be sent to the control unit, so that the operating frequency of the main piezoelectric ceramic 2 will become the newly measured natural frequency. The operating time of the main piezoelectric ceramic 2 can be set in the control unit. After the main piezoelectric ceramic 2 has operated for a certain period of time, the auxiliary piezoelectric ceramic 3 will be tested again. If the natural frequency is the same as the natural frequency in the ice-free state, it proves that the ice has been removed. The main piezoelectric ceramic 2 will resume operating at the natural frequency in the ice-free state. If the natural frequency is different from the natural frequency in the ice-free state, the above de-icing operation will be repeated until the ice is removed. No matter in an ice-free state or an ice-exposed state, the heating unit 1 is always working.

[0050] The application of the present invention is described below through two embodiments.

[0051] Example 1:

[0052] The solution of the present invention can be applied to arc-shaped or flat structures such as aircraft wings or wind turbine blades. The temperature of an aircraft changes greatly during flight, so it is easy for ice to form on the wing part. If the ice cannot be removed in a timely and effective manner, it will have a huge impact on the flight of the aircraft. Therefore, the heating unit 1 is evenly arranged on the span direction of the wing. The heating unit 1 used in this case is an electric heating resistor. H is the length in the span direction of 0.2m, T is 0.0174℃, Q is the total power on the heating resistor during deicing, 1.16W, H n is the distance between the electric heating resistance wires, H p is the thickness of the structure 2mm, λ is the thermal conductivity of the material 155W / (m·k), and l is the length of the electric heating resistance wire 62mm. Substitute the parameters into the formula It can be obtained that n is the total number of electric heating resistance wires to be arranged in the span direction, which is 19, with a spacing of 10.5 mm. The number of electric heating resistance wires to be arranged in the span direction of the entire structure can also be deduced in this way. The electric heating resistance wires and the thermal insulation layer 5 are installed on the inner side of the structure, as shown in FIG. Figure 2 As shown, this will not destroy the aerodynamic characteristics of the wing or blade surface. The thermal insulation layer 5 allows the heat generated by the electric heating resistance wire to flow unidirectionally toward the icing side, that is, the outside, reducing energy loss and improving energy utilization.

[0053] The main piezoelectric ceramic 2 is installed at the inner resonance point of the wing skin 4, which will not affect the dynamic characteristics. Figure 1 As shown, the secondary piezoelectric ceramic 3 acts as an exciter to generate an excitation, and the primary piezoelectric ceramic 2 acts as a sensor to obtain a signal, which is then analyzed to obtain a natural frequency. A natural frequency is selected as the excitation frequency of the excitation signal, allowing the primary piezoelectric ceramic 2 to operate at a resonant frequency. Because the resonant frequency changes with the mass of the ice layer on the wing, after the primary piezoelectric ceramic 2 is excited once to partially break and separate the ice, the secondary piezoelectric ceramic 3 measures the natural frequency again, keeping the excitation of the entire structure in a resonant mode, causing the structure to produce maximum shear deformation, and working together with the electric heating resistor to complete the de-icing task.

[0054] Example 2:

[0055] This structure can also be used for anti-icing and de-icing of power transmission cables. In addition to the electric heating resistance wire, which is wound into a ring on the cable, other ring-shaped heating units 1 that can be put on the cable can also be used in this application. There is no need to make major changes to the existing power transmission cables, and it only needs to be installed on the surface of the structure. The cylindrical shape of the cable is not conducive to the installation of piezoelectric ceramics. The fixed arm 6 is fixed to the cable, and the piezoelectric ceramics are installed on the uppermost plane of the fixed arm 6. Figure 3 As shown, the heating unit 1 and piezoelectric ceramics are arranged on the outer surface of the structure. Finally, according to the formula The installation spacing of the heating unit 1 is calculated, and the remaining operations are similar to those in the first embodiment.

[0056] In the structure of the present invention, the reasonable arrangement of the electric heating resistance wire maximizes the energy utilization rate during the heating process, and the problem of uneven heating will not occur; the combined heat and force de-icing greatly reduces energy consumption and greatly improves the de-icing speed; by real-time monitoring of the natural frequency, the excitation is always in the working mode of the current natural frequency, the shear deformation generated is maximum, and the de-icing effect is best; the de-icing unit can be installed on the inside or outside of the structure according to actual conditions, which is easy to install and maintain, and does not damage the original operating characteristics and aerodynamic performance of the structure; when there is no ice, the system can also play an anti-icing role to ensure the safe operation of the device.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A heat and force combined deicing structure, characterized in that: The device comprises a control unit, a main piezoelectric ceramic, a secondary piezoelectric ceramic, and a heating unit. The heating unit is arranged in an ice-prone area of the deicing device. The main piezoelectric ceramic is arranged at the resonance point of the deicing device. The control unit and the secondary piezoelectric ceramic are arranged in an ice-prone area of the deicing device. The secondary piezoelectric ceramic detects the natural frequency of the deicing device and sends it to the control unit. The control unit sends the natural frequency to the main piezoelectric ceramic via an excitation signal. The main piezoelectric ceramic generates ultrasonic guided waves for deicing after receiving the excitation signal. A deicing method for a heat and force combined deicing structure comprises the following steps: Step S1: Arrange the heating units in the area of the de-icing device that is prone to ice formation. The arrangement of the heating units is based on the formula Calculate, where H n is the distance between the heating units, Q is the total power of the heating units during deicing, H is the length of the heating units to be arranged along the span direction, T is the desired surface temperature of the deicing device, and H p is the thickness of the deicing device, λ is the thermal conductivity of the deicing device, and l is the length of the heating unit to be arranged; Step S2: placing the control unit and the secondary piezoelectric ceramic in an area that is less prone to ice formation, and placing the primary piezoelectric ceramic at the resonance point of the de-icing device; Step S3: The auxiliary piezoelectric ceramic detects the natural frequency of the de-icing device and sends it to the control unit. The control unit sends the measured natural frequency as the excitation frequency to the main piezoelectric ceramic to generate ultrasonic guided waves, so that the de-icing device vibrates and generates shear stress, and at the same time turns on the power of the heating unit to work for heating.

2. The heat and force combined deicing structure according to claim 1, characterized in that: The control unit, the main piezoelectric ceramic and the auxiliary piezoelectric ceramic are all arranged away from the heating unit.

3. The heat and force combined deicing structure according to claim 2, characterized in that: The power supply of the heating unit is connected to the control unit.

4. The heat and force combined deicing structure according to claim 1, characterized in that: The heating unit adopts an electric heating resistance wire.

5. The heat and force combined deicing structure according to claim 1, characterized in that: In step S1, the desired surface temperature of the de-icing device is The length of the heating unit along the extension direction needs to be arranged H = nH n , n is the total number of the heating units to be arranged along the span direction, and Q' is the heat flux density.

6. The heat and force combined deicing structure according to claim 5, characterized in that: In step S1, the total power of the heating unit during deicing is Q=nQ", Q" is the working power of each heating unit, Q"=H p *2*Q'l, Q' is the heat flux density.

7. The heat and force combined deicing structure according to claim 6, characterized in that: The step S3 comprises the following steps: Step S31: In an ice-free state, the secondary piezoelectric ceramic detects the natural frequency of the de-icing device, and uses the measured natural frequency in the ice-free state as the excitation frequency and sends it to the control unit. The control unit controls the primary piezoelectric ceramic to operate at the natural frequency in the ice-free state and turns on the heating unit. Step S32: After the main piezoelectric ceramic operates for a preset time, the auxiliary piezoelectric ceramic performs frequency detection on the de-icing device again. If the frequency is consistent with the natural frequency in the ice-free state, it is confirmed that the de-icing device is in the ice-free state. The main piezoelectric ceramic operates at the natural frequency in the ice-free state. If the frequency is inconsistent with the natural frequency in the ice-free state, it is confirmed that the de-icing device is in the ice-covered state, and the process proceeds to step S33. Step S33: sending the new natural frequency measured by the secondary piezoelectric ceramic to the control unit, so that the operating frequency of the primary piezoelectric ceramic becomes the new natural frequency measured, and then proceeding to step S32.

8. The heat and force combined deicing structure according to claim 7, characterized in that: The auxiliary piezoelectric ceramic selects the natural frequency with the maximum energy from the measured natural frequencies as the excitation frequency.

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