Vibration-based low-temperature surface frosting regulation and control device and method

Abstract

The invention relates to a low-temperature surface frosting regulation and control device and method based on vibration, belongs to the technical field of frost suppression, and particularly relates to a technology for controlling and predicting a frosting process by regulating surface vibration characteristics. According to the method, the cold surface vibrates in different modes by adjusting the vibration waveform, the vibration amplitude, the frequency, the phase, the duty ratio and other vibration characteristics of the cold surface, so that control over the frosting stage and the frosting degree is achieved, the frost layer growth rule under the different vibration characteristics is obtained, and the frosting effect is improved. The purposes of predicting frosting and inhibiting frosting by regulating and controlling the vibration characteristics of the frosting surface are achieved.

Description

Technical Field

[0001] The present invention relates to a vibration-based low-temperature surface frosting control device and method, belonging to the field of frosting suppression technology, and specifically relates to a technology for controlling and predicting the frosting process by adjusting the surface vibration characteristics. Background Art

[0002] The frosting phenomenon is widespread in fields such as energy, aerospace, power transmission, and navigation. The formation of the frost layer not only affects the surface characteristics of the object, but also increases the thermal resistance of the heat exchanger, reduces the heat transfer efficiency, increases energy consumption, and even damages the heat exchange equipment, causing economic losses. Therefore, predicting and effectively controlling surface frosting is an important research direction in the frosting suppression technology. It should be noted that in practical applications, the frosting surface is not in an ideal static state, and usually has vibrations in different forms and directions due to factors such as movement and fluid impact. Surface vibration will affect the heat transfer and phase change processes, and also change the frosting process. Therefore, it is necessary to analyze the frosting characteristics of the frosting surface under the influence of vibration factors to improve the operation efficiency and reliability of the equipment, and provide strategies for optimizing the frosting control of the system.

[0003] Existing frosting suppression technologies generally directly intervene in the physical properties of the frost layer, passively suppress frosting through surface modification technology, and actively suppress frosting by combining physical means. The patent "A processing method for an air source heat pump high-efficiency defrosting fin heat exchanger" with the patent application number 202411507858.7 is based on surface modification technology. By means of hydrophobic coating, superlubrication treatment, and surface structure optimization, the adhesion of the frost layer is reduced, and the frosting speed is delayed. This scheme has significant advantages in a mild frosting environment, but under long-term thermal cycling, mechanical vibration, and ice crystal impact, the coating is prone to microstructural wear, there is a risk of hydrophobic coating failure, and the hydrophilic-hydrophobic spacer layer may damage the heat transfer continuity of the fin surface, resulting in an increase in local thermal resistance and a reduction in the heat exchange effect. The patent "An intelligent defrosting air source heat pump" with the patent application number 202411948366.1 combines physical means (ultrasonic wave, vibration drive) to accelerate the shedding of the frost layer. Through the design of a vibration drive mechanism and a drainage part, the frost layer structure is directly destroyed. This scheme has innovative value in a conventional temperature and humidity environment, but it is necessary to focus on breaking through the problem of energy consumption optimization. The vibration drive and ultrasonic devices will cause an additional energy consumption burden. If the influence law of the vibration working condition on the frosting process is known, the optimization of this scheme in terms of additional energy consumption burden can be achieved.

[0004] Existing frosting suppression technologies generally do not consider the influence of vibration, and there are the following problems: (1) The processing complexity of the surface modification technology is high, and it is impossible to accurately control the hydrophilic-hydrophobic ratio of the local area, and the frosting in the edge area still accelerates; (2) During the process of defrosting by the cooperation of vibration and ultrasonic wave, there is a contradiction between energy efficiency and process control, and it is difficult to achieve energy efficiency balance, resulting in an increase in the overall energy consumption; (3) When the vibration mechanism works, it will change the frost layer structure, which may lead to an acceleration of the frost layer growth and a reduction in the frosting suppression effect. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: to overcome the deficiencies of the prior art and propose a vibration-based low-temperature surface frosting control device and method.

[0006] The technical solution of the present invention is:

[0007] A vibration-based low-temperature surface frosting control device, which includes a vibration device 1, a refrigeration unit 2, an experimental section 3, an environmental chamber 4, and a frost layer information acquisition device 5;

[0008] The vibration device 1 is a device or component that generates vibration, such as an electromagnetic exciter, a pneumatic vibrator, a ceramic sheet, a speaker, etc.;

[0009] The refrigeration unit 2 can use a semiconductor refrigeration device, an absorption refrigeration device, or a compression refrigeration device, which is used to supply cold to the experimental section 3 and transmit the surface temperature of the experimental section 3 through a resistance thermometer or a thermocouple temperature sensor;

[0010] The experimental section 3 can be made of copper, aluminum, or common frosting materials and is used as a vibrating frosting surface;

[0011] The environmental chamber 4 is used to provide the temperature and humidity of the experimental environment and can use a small experimental chamber or a closed laboratory;

[0012] The frost layer information acquisition device 5 can be a CCD industrial camera or a high-speed camera;

[0013] The refrigeration unit 2 is attached to the lower surface of the experimental section 3 to provide cold for the frosting process of the experimental section 3 and maintain a stable cold surface temperature;

[0014] The vibration device 1 is connected to the refrigeration unit 2 and the experimental section 3 to provide vibration for the experimental section 3;

[0015] The frost layer information acquisition device 5 is used to collect the frost layer information on the surface of the experimental section 3.

[0016] A vibration-based low-temperature surface frosting control method, the steps of which include:

[0017] The first step is to start the vibration device 1 and collect the vibration characteristic parameters of the vibration device 1;

[0018] The second step is to start the refrigeration unit 2 and cool the surface of the experimental section 3 through the refrigeration unit 2 until the surface temperature of the experimental section 3 reaches the set value;

[0019] The third step is to photograph the frost layer growth process on the surface of the experimental section 3 through the frost layer information acquisition device 5;

[0020] Fourthly, collect the frost layer growth parameters in the video shot in the third step, and perform data processing on the collected frost layer growth parameters and the vibration characteristic parameters of the vibration device 1 collected in the first step;

[0021] Fifthly, according to the data processing results in the fourth step, check whether the requirements of the project for the frost layer growth parameters are met. If not, change the vibration characteristic parameters of the vibration device 1 in the first step and enter the second step until the inspection results meet the project requirements.

[0022] In the first step, the vibration characteristic parameters include parameters such as vibration waveform, phase, duty cycle, frequency, and amplitude. The vibration waveform is a sine wave, cosine wave, square wave, or sawtooth wave;

[0023] In the fourth step, the frost layer growth parameters include the frost layer growth thickness at different times, frost layer growth rate, frost layer surface roughness, frosting start time, frost layer mass, frost layer density, etc.;

[0024] In the fourth step, performing data processing means calculating the frost layer growth thickness h(t,a) at different times as:

[0025] h(t,a)=(k0 + k1a)ln(t)+(b0 + b1a)

[0026] a=(2πf) 2 A

[0027] where h(t,a) is the frost layer growth thickness at different times, with the unit of μm;

[0028] a is the vibration acceleration, with the unit of μm / s 2 ;

[0029] A is the amplitude, with the unit of μm;

[0030] f is the frequency, with the unit of Hz;

[0031] k0, k1, b0, and b1 are all constants;

[0032] t is the time, with the unit of s.

[0033] Beneficial effects

[0034] By adjusting the vibration waveform, as well as vibration characteristics such as amplitude, frequency, phase, and duty cycle of the cold surface, the present invention enables the cold surface to vibrate in different ways, thereby achieving the control of the frosting stage and the degree of frosting, obtaining the frosting growth law under different vibration characteristics, and achieving the purpose of predicting and suppressing frosting by regulating the vibration characteristics of the frosting surface. By changing vibration characteristics such as amplitude and frequency, the balance between the growth characteristics and morphological characteristics of the frost layer is achieved, and then frosting characteristics such as frosting thickness, frost layer mass, frost layer density, frost layer roughness, and frosting start time are controlled. A frosting prediction model is constructed based on the coupled data of vibration characteristic parameters and frost layer growth parameters, and the active control of frosting is realized through real-time feedback adjustment of vibration characteristics.

[0035] The frosting control technology of the present invention can achieve the regulation of the physical properties of frosting only by adjusting the vibration characteristics, without the need for too many additional devices, and has the characteristics of simple method and low cost. The technology proposed by the present invention can simulate the real vibration conditions of rotating components, and combine the material properties of components and the characteristics of the working environment to achieve a high-precision reproduction of the real frosting process. The technology proposed by the present invention can obtain the mutual influence mechanism between the morphological characteristics and growth characteristics during the growth process of the frost layer under vibration conditions, and the relevant conclusions can be used to guide and improve the frosting problems of low-temperature vibrating surfaces such as air-source heat pump evaporators, fan blades, and aircraft wings. The vibration-based frosting control method for low-temperature surfaces proposed in the present invention is not limited to the low-frequency sine wave vibration in the embodiments, and different vibration forms are also within the scope of the frosting control method proposed in the present invention. The vibration-based frosting control method for low-temperature surfaces proposed in the present invention is not limited to predicting and controlling the frosting thickness, frost layer growth rate, and frost layer growth roughness listed in the embodiments, and the control of parameters such as the frosting stage, frost layer mass, and frost layer density is within the protection scope of the present invention. The material used for the cold surface in the present invention can be replaced with other metal or non-metal materials. Description of the Drawings

[0036] Figure 1 is a schematic diagram of the device of the present invention;

[0037] Figure 2 is the response surface of the influence of vibration acceleration on the growth thickness of the frost layer within 1800s;

[0038] Figure 3 is a comparison diagram of the growth thickness of the frost layer over time at different amplitudes;

[0039] Figure 4 is a comparison diagram of the growth rate of the frost layer over time at different amplitudes;

[0040] Figure 5 is a comparison diagram of the growth roughness of the frost layer over time at different amplitudes;

[0041] Figure 6 It is a comparison graph of the growth thickness of the frost layer changing with time at different frequencies. Specific implementation manners

[0042] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0043] As Figure 1 shown, a vibration-based low-temperature surface frosting control device includes a vibration device 1, a refrigeration unit 2, an experimental section 3, an environmental chamber 4, and a frost layer information acquisition device 5;

[0044] The vibration device 1 can be a device or component that generates vibration, such as an electromagnetic exciter, a pneumatic vibrator, a ceramic sheet, a speaker, etc.; the refrigeration unit 2 can use a semiconductor refrigeration device, an absorption refrigeration device or a compression refrigeration device to supply cold to the experimental section 3, and transfer the surface temperature of the experimental section 3 through a resistance thermometer or a thermocouple temperature sensor; the experimental section 3 can be made of copper, aluminum or common frosting materials and is used as a vibrating frosting surface; the environmental chamber 4 is used to maintain the stability of the temperature and humidity of the experimental environment, and a small experimental chamber or a closed laboratory can be adopted; the frost layer information acquisition device 5 can be a CCD industrial camera or a high-speed camera;

[0045] The refrigeration unit 2 is attached to the lower surface of the experimental section 3 to provide cold for the frosting process and maintain a stable cold surface temperature; the vibration device 1 is connected to the refrigeration unit 2 and the experimental section 3 to provide vibration for the experimental section 3;

[0046] In the initial state, an input set initial vibration signal is used to turn on the vibration device 1. After the vibration is stable, the refrigeration unit 2 is turned on for cooling. When the set temperature is reached, the frost layer information acquisition device 5 is used to photograph the growth process of the frost layer, and the photographed results are processed to extract the frost layer growth parameters. By continuously changing the vibration characteristic parameters, frosting can be regulated to achieve the effect of controlling the growth of the frost layer. In addition, by adjusting the vibration characteristic parameters and synchronously iterating the parameter data set, a vibration influence frost layer growth model is calculated. According to the model law, when vibration occurs, both the heat and mass transfer effect between the frost layer and the outside and the inertial force caused by surface vibration will change and compete with each other. In the low-frequency micron-level vibration range, as the amplitude and frequency of the vibration increase, the frosting degree will intensify.

[0047] The above-mentioned frosting control method uses changing the main characteristic parameters of vibration, such as amplitude and frequency, etc., to predict and regulate the frosting degree;

[0048] The above method for regulating the frosting degree by vibration only needs to change the vibration characteristic parameters of the vibration device 1 to adjust the real-time growth thickness of the frost layer. Without excessive additional devices, it has the characteristics of simple method and low cost. In addition, the vibration regulation frosting technology can continuously iterate and optimize the vibration frosting model by expanding the working conditions and enriching the data, and establish a map, so as to control the growth characteristics of the frost layer under the coupling action of low-temperature vibration factors and accurately predict and regulate the frosting degree in more complex actual working conditions.

[0049] The above vibration regulation frosting method includes the following steps:

[0050] In the first step, start the vibration device 1 and collect the vibration characteristic parameters of the vibration device 1;

[0051] In the second step, start the refrigeration unit 2, and refrigerate the surface of the experimental section 3 through the refrigeration unit 2 until the surface temperature of the experimental section 3 reaches the set value;

[0052] In the third step, use the frost layer information collection device 5 to photograph the frost layer growth process on the surface of the experimental section 3;

[0053] In the fourth step, collect the frost layer growth parameters in the video taken in the third step, and perform data processing on the collected frost layer growth parameters and the vibration characteristic parameters of the vibration device 1 collected in the first step;

[0054] In the fifth step, according to the data processing results of the fourth step, check whether the requirements of the project for the frost layer growth parameters are met. If not, change the vibration characteristic parameters of the vibration device 1 in the first step and enter the second step until the inspection results meet the project requirements.

[0055] In the first step, the vibration characteristic parameters include parameters such as vibration waveform, phase, duty cycle, frequency and amplitude. The vibration waveform is a sine wave, cosine wave, square wave or sawtooth wave;

[0056] In the fourth step, the frost layer growth parameters include the frost layer growth thickness at different times, frost layer growth rate, frost layer surface roughness, start frosting time, frost layer mass, frost layer density, etc.;

[0057] In the fourth step, performing data processing means calculating the frost layer growth thickness h(t,a) at different times as:

[0058] h(t,a) = (k0 + k1a)ln(t) + (b0 + b1a)

[0059] a = (2πf) 2 A

[0060] where h(t,a) is the frost layer growth thickness at different times, with the unit of μm;

[0061] a is the vibration acceleration, with the unit of μm / s 2 ;

[0062] A is the amplitude, with the unit of μm;

[0063] f is the frequency, with the unit of Hz;

[0064] k0, k1, b0 and b1 are all constants;

[0065] t is the time, with the unit of s.

[0066] The surface of the frost layer growth thickness affected by the vibration acceleration within 1800 s is as Figure 2 shown.

[0067] Example 1

[0068] A vibration-based low-temperature surface frosting control device, which includes a vibration device 1, a refrigeration unit 2, an experimental section 3, an environmental chamber 4 and a frost layer information acquisition device 5;

[0069] The vibration device 1 is an electromagnetic shaker;

[0070] The refrigeration unit 2 uses a semiconductor refrigeration device to supply cold to the experimental section 3 and monitors the surface temperature of the experimental section 3 through a thermocouple temperature sensor;

[0071] The experimental section 3 uses a bare copper sheet as the vibrating frosting surface;

[0072] The environmental chamber 4 is used to provide the temperature and humidity of the experimental environment. A small experimental chamber is adopted, and the temperature and humidity of the experimental environment are set to 23°C and 60%RH respectively;

[0073] The frost layer information acquisition device 5 is a CCD industrial camera;

[0074] The refrigeration unit 2 is attached to the lower surface of the experimental section 3 to provide cold for the frosting process of the experimental section 3 and maintain a stable cold surface temperature;

[0075] The vibration device 1 is connected to the refrigeration unit 2 and the experimental section 3 to provide vibration for the experimental section 3;

[0076] The frost layer information acquisition device 5 is used to collect the frost layer growth information on the surface of the experimental section 3;

[0077] A vibration-based low-temperature surface frosting control method is adopted. The steps of this method include:

[0078] First step, start the vibration device 1 and set the frequency f of the vibration device 1 to 50 Hz, the waveform is a sine wave, the phase is 0, the duty cycle is 50%, and the amplitudes are 0 μm, 500 μm and 1000 μm respectively;

[0079] In the second step, start the refrigeration unit 2 to cool the surface of the bare copper through the refrigeration unit 2 until the monitored temperature of the bare copper surface reaches the set value of -10°C;

[0080] In the third step, use the frost layer information acquisition device 5 to photograph the growth process of the frost layer on the surface of the bare copper;

[0081] In the fourth step, collect the frost layer growth parameters in the video taken in the third step, and perform data processing on the collected frost layer growth parameters and the vibration characteristic parameters of the vibration device 1 collected in the first step. The frost layer growth thicknesses at different times within 30 min are as Figure 3 shown; with the increase of the amplitude, the frost layer thickness at the same moment also increases significantly. The frost layer thicknesses under the amplitude conditions of 0μm, 500μm, and 1000μm at 30 min are 771.14μm, 920.71μm, and 1136.59μm respectively.

[0082] When the frequency f = 50Hz, the relationship between the frost layer growth thickness and different amplitudes with time is as follows:

[0083] h(t,a)=(478.76 + 2.74×10 -9 a)ln(t)-2873.24 + 3.58×10 -6 a

[0084] In the formula, h(t,a) is the frost layer growth thickness, μm; a is the vibration acceleration, μm / s 2 ; t is the frosting time, s.

[0085] As Figure 3 shown, the theoretical curve accurately captures the change characteristics of the experimental data, and shows the rule that with the increase of the amplitude, the vibration acceleration increases and the frost layer growth thickness increases at the same frequency, indicating that this experimental method can be used to control the vibration frosting process.

[0086] The relationship between the frost layer growth rate at different amplitudes and the frost layer growth at different times under the frequency f = 50Hz, and the relationship between the frost layer roughness at different amplitudes and the frost layer growth at different times are as Figure 4 and Figure 5 shown. The theoretical curves all capture the change characteristics of the experimental data and show a certain rule in the fluctuation range of the data, which also indicates that this method can be used to control the vibration frosting process.

[0087] Example 2

[0088] Same as Example 1, the difference is that:

[0089] sThe experimental section 3 uses a bare aluminum sheet as the vibration frosting surface;

[0090] First step, start the vibration device 1 and set the amplitude A of the vibration device 1 to 500 μm, the waveform to a sine wave, the phase to 0, the duty cycle to 50%, and the frequencies to 0 Hz, 50 Hz, and 100 Hz respectively;

[0091] The frost layer growth thicknesses at different times within 30 min are as Figure 6 shown. As the vibration frequency increases, the frost layer thickness at the same moment also increases. The frost layer thicknesses under the frequency conditions of 0 Hz, 50 Hz, and 100 Hz at 30 min are 464.34 μm, 540.60 μm, and 541.45 μm respectively.

[0092] When the amplitude is A = 500 μm, the relationship between the frost layer growth thickness and different frequencies changing with time can be obtained as follows:

[0093] h(t,a) = (232.61 + 1.84×10 -2 a)ln(t) - 1255.94 + 1.05×10 -7 a

[0094] In the formula, h(t,a) is the frost layer growth thickness, μm; a is the vibration acceleration, μm / s 2 ; t is the frosting time, s.

[0095] As Figure 6 shown, the theoretical curve accurately captures the variation characteristics of the experimental data and shows the law that as the frequency increases, the acceleration increases, and the frost layer growth thickness increases under the same amplitude, indicating that this method can be used to control the vibration frosting process.

[0096] Obviously, those skilled in the art can make various changes and modifications to the embodiments of the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these changes and modifications.

[0097] In summary, the above are only the preferred embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A vibration-based low-temperature surface frosting control device, characterized in that: The control device includes a vibration device (1), a refrigeration unit (2), an experimental section (3), an environmental chamber (4), and a frost layer information acquisition device (5); The refrigeration unit (2) is attached to the lower surface of the experimental section (3) and is used to provide cooling capacity for the frosting process of the experimental section (3); The vibration device (1) is connected to the refrigeration unit (2) and the experimental section (3), and the vibration device (1) is used to provide vibration for the experimental section (3); The frost layer information acquisition device (5) is used to acquire the frost layer characteristic parameters on the surface of the experimental section (3); The environmental chamber (4) is used to provide the temperature and humidity of the experimental environment.

2. The vibration-based low-temperature surface frosting control device according to claim 1, characterized in that: The vibration device (1) is an electromagnetic vibrator, a pneumatic vibrator, a ceramic sheet, or a speaker.

3. The vibration-based low-temperature surface frosting control device according to claim 1, characterized in that: The refrigeration unit (2) is a semiconductor refrigeration device, an absorption refrigeration device, or a compression refrigeration device, and is used to supply cold to the experimental section (3), and the surface temperature of the experimental section (3) is monitored by a resistance thermometer or a thermocouple temperature sensor.

4. The vibration-based low-temperature surface frosting control device according to claim 1, characterized in that: The material of the experimental section (3) is copper, aluminum, or a common frosting material and is used as a vibrating frosting surface.

5. The vibration-based low-temperature surface frosting control device according to claim 1, characterized in that: The environmental chamber (4) adopts a small experimental chamber or a closed laboratory.

6. The vibration-based low-temperature surface frosting control device according to claim 1, characterized in that: The frost layer information acquisition device (5) is a CCD industrial camera or a high-speed camera.

7. A vibration-based low-temperature surface frosting control method, characterized in that The steps of this method include: The first step is to start the vibration device (1) and acquire the vibration characteristic parameters of the vibration device (1); The second step is to start the refrigeration unit (2) and cool the surface of the experimental section (3) through the refrigeration unit (2) until the surface temperature of the experimental section (3) reaches the set value; The third step is to photograph the frost layer growth process on the surface of the experimental section (3) through the frost layer information acquisition device (5); The fourth step is to acquire the frost layer growth parameters in the video taken in the third step, and perform data processing on the acquired frost layer growth parameters and the vibration characteristic parameters of the vibration device (1) acquired in the first step; The fifth step is to check whether the requirements of the project for the frost layer growth parameters are met according to the data processing results of the fourth step. If not, change the vibration characteristic parameters of the vibration device (1) in the first step and enter the second step until the inspection results meet the project requirements.

8. The vibration-based low-temperature surface frosting control method according to claim 7, characterized in that: In the first step, the vibration characteristic parameters include parameters such as vibration waveform, phase, duty cycle, frequency, and amplitude, and the vibration waveform is a sine wave, a cosine wave, a square wave, or a sawtooth wave.

9. The vibration-based low-temperature surface frosting control method according to claim 8, characterized in that: In the fourth step, the frost layer growth parameters include the frost layer growth thickness at different times, the frost layer growth rate, the frost layer surface roughness, the frosting start time, the frost layer mass, and the frost layer density.

10. A vibration-based low-temperature surface frosting control method according to claim 9, characterized in that: In the fourth step, data processing refers to calculating the frost layer growth thickness h(t,a) at different times as: h(t,a) = (k0 + k1a)ln(t) + (b0 + b1a) a = (2πf) 2 A where h(t,a) is the frost layer growth thickness at different times, in μm; a is the vibration acceleration, with the unit of μm / s 2 ; A is the amplitude, in μm; f is the frequency, in Hz; k0, k1, b0, and b1 are all constants; t is the time, in s.

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