A calculation model and test method, system and equipment for static convection heat exchange on an iced conductor surface and a medium

Abstract

The application relates to the technical field of iced conductors, and discloses a calculation model and a test method, system, equipment and medium for static convection heat exchange on the surface of an iced conductor, the method comprising the following steps: arranging an iced conductor, an infrared temperature measurement array and a test power supply in a controllable temperature environment, and adjusting the surface temperature of the iced conductor by applying current to the iced conductor through the test power supply; starting the test under constant environmental temperature, synchronously collecting temperature data of the infrared temperature measurement array, and collecting the temperature data until the temperature of any measuring point reaches zero Celsius; calculating a curve of average temperature of the iced surface changing with time based on the collected data, combining the environmental temperature and air physical property parameters, and sequentially calculating a dimensionless number product representing natural convection intensity, a natural convection Nusselt number, a natural convection heat exchange coefficient of the outer surface of the ice layer, an equivalent natural convection heat dissipation thermal resistance of the conductor per unit length, a natural convection heat dissipation heat flow of the conductor per unit length, and cumulative heat dissipated by natural convection of the conductor per unit length in the test.

Description

Technical Field

[0001] This invention relates to the field of icing conductor technology, and in particular to a calculation model, testing method, system, equipment and medium for static convective heat transfer on the surface of an icing conductor. Background Technology

[0002] During the de-icing process of iced conductors, the characteristics of static convection heat dissipation directly affect the de-icing efficiency and energy loss. Traditional de-icing schemes for iced conductors are usually designed based on empirical parameters. Although they emphasize the setting of de-icing power and time, they lack accurate calculation of key parameters of static convection heat transfer.

[0003] Because the calculation operation involves multi-dimensional environmental and conductor parameters, and the temperature change and static convection heat transfer law of the ice-covered surface are complex, it is difficult to conduct a more accurate analysis and control of the heat dissipation characteristics during the ice melting process from an empirical perspective.

[0004] Furthermore, in complex temperature environments, existing technologies cannot accurately extract core parameters such as convective heat transfer coefficients or heat flux, let alone optimize existing ice melting solutions by extracting these parameters. Summary of the Invention

[0005] In view of the aforementioned existing problems, the present invention is proposed.

[0006] Therefore, this invention provides a calculation model, testing method, system, equipment, and medium for static convective heat transfer on the surface of iced conductors. This can solve the technical problem in traditional icing conductor melting schemes where the lack of accurate calculation of key static convective heat transfer parameters makes it difficult to accurately extract core parameters to optimize the melting scheme under complex temperature field environments.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a calculation model and testing method for static convective heat transfer on the surface of an icing conductor, including: Arrange the ice-covered wires, infrared temperature measurement array, and test power supply in a temperature-controlled environment; The temperature of the ice-covered surface is adjusted by applying current to the ice-covered wire using a test power source. The static convection heat transfer test was initiated while maintaining a constant ambient temperature. Simultaneously acquire temperature data output from the infrared temperature measurement array until the temperature at any measuring point reaches zero degrees Celsius; The curve of the average temperature of the ice-covered surface changing over time was calculated based on the collected temperature data; Based on the average temperature curve of the ice-covered surface, ambient temperature, and air properties, the dimensionless product of natural convection intensity, the natural convection Nusselt number, the natural convection heat transfer coefficient of the outer surface of the ice layer, the equivalent natural convection heat dissipation thermal resistance per unit length of the conductor, the natural convection heat flux per unit length of the conductor, and the cumulative heat lost by the conductor per unit length of the conductor through natural convection during the test are calculated sequentially.

[0008] As a preferred embodiment of the calculation model and testing method for static convective heat transfer on the surface of the iced conductor described in this invention, the arrangement of the iced conductor, the infrared temperature measurement array, and the infrared temperature measurement array in the test power supply in a temperature-controlled environment includes: Multiple temperature measurement sections are set along the length of the icing conductor. Each temperature measurement section has four infrared temperature measurement units evenly arranged in the circumference, corresponding to the upper, lower, left, and right directions respectively.

[0009] As a preferred embodiment of the calculation model and testing method for static convective heat transfer on the surface of an iced conductor according to the present invention, the calculation of the curve of the average temperature of the iced surface changing with time includes: The arithmetic mean of the temperature values ​​output by all infrared temperature measurement units at each sampling time is used to form the average temperature of the icy surface at that time. The average surface temperature of the ice-covered area at each time point was then plotted as a curve in chronological order.

[0010] As a preferred embodiment of the calculation model and testing method for static convective heat transfer on the surface of an icing conductor according to the present invention, wherein: the calculation of the dimensionless product characterizing the intensity of natural convection includes: The numerators are gravitational acceleration, the cube of the difference between the average temperature of the ice-covered surface and the ambient temperature, the specific heat capacity of air, and the aerodynamic viscosity. The ratio calculated by using the square of the air kinematic viscosity and the air thermal conductivity as the denominator is the product of the dimensionless numbers.

[0011] As a preferred embodiment of the calculation model and testing method for static convective heat transfer on the surface of the icing conductor described in this invention, the step of calculating the natural convection Nusselt number includes: Take the natural logarithm of the dimensionless product of the dimensions representing the intensity of natural convection; Multiply the result by the first fitting coefficient and add the second fitting coefficient to obtain the natural convection Nusselt number. The first and second fitting coefficients were determined through experimental calibration.

[0012] As a preferred embodiment of the calculation model and testing method for static convective heat transfer on the surface of the icing conductor described in this invention, the step of calculating the natural convective heat flux per unit length of the conductor includes: Multiply by pi, the outer diameter of the ice-covered conductor, and the natural convection heat transfer coefficient of the outer surface of the ice layer; Multiplying this by the difference between the average temperature of the ice-covered surface and the ambient temperature, we obtain the natural convection heat flow per unit length of conductor at the corresponding moment.

[0013] As a preferred embodiment of the calculation model and testing method for static convective heat transfer on the surface of the icing conductor described in this invention, the step of calculating the cumulative heat loss per unit length of conductor through natural convection during the test includes: Multiply the natural convection heat flux calculated at each sampling time by the sampling time interval; The cumulative heat is obtained by summing the multiplications accumulated over all sampling times.

[0014] Secondly, the present invention provides a calculation model and testing system for static convective heat transfer on the surface of an icing conductor, comprising: Temperature-controlled environment chamber, used to provide a testing space with a constant ambient temperature; The ice-covered conductor is installed inside the temperature-controlled environment chamber and its surface is covered with a uniform layer of ice. The test power supply, connected to both ends of the ice-covered wire, is used to apply current to the ice-covered wire to regulate the temperature of the ice-covered surface; An infrared temperature measurement array is arranged around the icing conductor to simultaneously collect temperature data at multiple locations on the surface of the icing conductor during the test until the temperature at any measuring point reaches zero degrees Celsius. The data processing unit, which is communicatively connected to the infrared temperature measurement array, is used to receive temperature data and perform the following operations: calculate the curve of the average temperature of the ice-covered surface changing over time; and based on the curve, ambient temperature, and air properties, sequentially calculate the dimensionless product of natural convection intensity, the natural convection Nusselt number, the natural convection heat transfer coefficient of the outer surface of the ice layer, the equivalent natural convection heat dissipation thermal resistance per unit length of the conductor, the natural convection heat flux per unit length of the conductor, and the cumulative heat lost by the conductor per unit length through natural convection during the test.

[0015] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method described above.

[0016] Fourthly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described above.

[0017] Compared with existing technologies, the beneficial effects of this invention are that it proposes a calculation model and testing method for static convective heat transfer on the surface of an icing conductor. An icing conductor, an infrared temperature measurement array, and a test power supply are arranged in a temperature-controlled environment. Current is applied to the icing conductor through the test power supply to adjust its surface temperature. The test is started under constant ambient temperature, and temperature data output from the infrared temperature measurement array is collected synchronously until the temperature at any measuring point reaches zero degrees Celsius. Based on the collected temperature data, a curve showing the average temperature of the icing surface changing over time is calculated. Combined with ambient temperature and air properties, the dimensionless product characterizing the intensity of natural convection, the Nusselt number of natural convection, the natural convection heat transfer coefficient of the outer surface of the ice layer, the equivalent natural convection thermal resistance per unit length of conductor, the natural convection heat flux per unit length of conductor, and the cumulative heat lost per unit length of conductor through natural convection during the test are calculated sequentially. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating a calculation model and testing method for static convective heat transfer on the surface of an icing conductor, provided as an embodiment of the present invention.

[0020] Figure 2 is an example diagram of a static convection heat transfer measurement system for an icing conductor, which provides a calculation model and test method for static convection heat transfer on the surface of an icing conductor according to an embodiment of the present invention. (a) Schematic diagram of the arrangement of the static convection heat transfer measurement system for the icing conductor, and (b) Positional relationship between the four sets of infrared temperature measurement units and the icing conductor.

[0021] Figure 3 An example graph showing the Prandtl number-Grashof number product and the outer surface temperature of the ice layer with respect to the ambient temperature difference in a calculation model and test method for static convective heat transfer on the surface of an icing conductor, provided in an embodiment of the present invention.

[0022] Figure 4 An example graph showing the natural convection Nusselt number and the outer surface temperature of the ice layer with respect to the ambient temperature difference, for a calculation model and test method of static convective heat transfer on the surface of an ice-covered conductor provided in an embodiment of the present invention.

[0023] Figure 5 This is a schematic diagram of the average temperature curve of the iced surface during the test period of a calculation model and test method for static convective heat transfer on the surface of an iced conductor, provided as an embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of the Prandtl number-Grashof number product curve during the test period of a calculation model and test method for static convective heat transfer on the surface of an icing conductor provided in an embodiment of the present invention.

[0025] Figure 7 This is a schematic diagram of the Nusselt number curve during the test period of a calculation model and test method for static convective heat transfer on the surface of an icing conductor provided in an embodiment of the present invention.

[0026] Figure 8 This is a schematic diagram of the equivalent natural convection resistance during the testing period of a calculation model and testing method for static convection heat transfer on the surface of an icing conductor, provided as an embodiment of the present invention.

[0027] Figure 9 This is a schematic diagram of the natural convection heat flux curve of a unit length of conductor during the test, which is provided as a calculation model and test method for static convection heat transfer on the surface of an icing conductor according to an embodiment of the present invention.

[0028] Figure 10 This is a schematic diagram of the cumulative heat dissipation per unit length of conductor during the test, provided as an embodiment of the present invention, for a calculation model and test method of static convection heat transfer on the surface of an icing conductor.

[0029] Figure 11 This is an internal structural diagram of an electronic device that provides a calculation model and testing method for static convection heat transfer on the surface of an icing conductor, as provided in one embodiment of the present invention. Detailed Implementation

[0030] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0031] It should be noted in advance that the system mentioned in the embodiments as the subject of real-time operation refers to any system configured with this method.

[0032] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a calculation model and testing method for static convective heat transfer on the surface of an icing conductor, including: This invention provides a method that can effectively solve the problems mentioned above. The following will describe in detail how to realize the calculation model and test method for static convection heat transfer on the surface of the icing conductor with multiple embodiments. Figure 1 A flowchart illustrating a calculation model and testing method for static convective heat transfer on the surface of an icing conductor is shown, including: S101, arranging ice-covered wires, infrared temperature measurement array and test power supply in a temperature-controlled environment; In an embodiment of the present invention, the arrangement of the icing wires, the infrared temperature measurement array, and the infrared temperature measurement array in the test power supply in a temperature-controlled environment includes: Multiple temperature measurement sections are set along the length of the icing conductor. Each temperature measurement section has four infrared temperature measurement units evenly arranged in the circumference, corresponding to the upper, lower, left, and right directions respectively.

[0033] It is understandable that when the surface temperature distribution of the icing conductor is uneven due to natural convection heat transfer, resulting in a circumferential temperature difference, if an infrared temperature measurement unit is only placed in a single direction, the collected temperature data will not be able to accurately reflect the overall thermal state of the icing surface.

[0034] If only a single temperature measurement section is set along the length of the conductor, temperature measurement deviations may occur due to local differences in ice thickness or environmental disturbances, which in turn will affect the accurate calculation of the natural convection heat transfer coefficient and cumulative heat dissipation.

[0035] Therefore, the present invention sets multiple temperature measuring sections along the length of the ice-covered wire inside the temperature-controlled environment chamber, and each temperature measuring section is uniformly set with four infrared temperature measuring units in the circumferential direction, corresponding to the upper, lower, left and right directions respectively.

[0036] The aforementioned multiple temperature measurement sections can be understood as spatial sampling positions used in this invention to capture the axial temperature gradient changes of the icy conductor, ensuring that the acquired temperature data can cover the thermal response characteristics of the entire length of the conductor; the aforementioned four infrared temperature measurement units can be understood as a sensing configuration used in this invention to simultaneously monitor the temperature distribution in different circumferential directions of the same section, in order to eliminate the systematic errors caused by the vertical temperature difference or the asymmetrical heat dissipation caused by gravity-driven natural convection on the average temperature calculation.

[0037] S102, apply current to the ice-covered wire through the test power supply to adjust the temperature of the ice-covered surface; It should be noted that when the icing conductor is in a state of natural convection heat transfer in a temperature-controlled environment chamber, if the surface temperature of the icing is passively adjusted by relying solely on the ambient temperature, the surface temperature will change slowly and cannot be precisely controlled, making it difficult to achieve active intervention at different stages of thermal response.

[0038] If an external heating device is used to heat the entire ice layer in a non-contact manner, uneven heat distribution may cause localized melting or thermal stress concentration, thereby damaging the integrity of the ice layer structure and affecting the accurate inversion of the natural convection heat transfer coefficient and cumulative heat dissipation.

[0039] Therefore, this invention applies current to the icing conductor through a test power source to adjust the surface temperature of the ice, and uses the conductor's own resistance to generate heat to achieve uniform internal heating, ensuring that the surface temperature of the ice rises steadily according to the preset thermal conditions, while avoiding interference factors introduced by external heat sources.

[0040] The aforementioned test power supply can be understood as a power supply device used in this invention to provide an adjustable constant current output to drive the icing wire to generate Joule heating. Its output current amplitude directly determines the heat generated by the wire per unit time, thereby precisely controlling the temperature evolution path of the icing surface.

[0041] S103, Static convection heat transfer test is started under the condition of maintaining constant ambient temperature; It should be noted that in actual operation, if there are temperature fluctuations in the heat exchange environment of the icing conductor during the de-icing process, it will interfere with the stability of the natural convection heat transfer process, and this stability directly determines the accuracy of the physical correlation between surface temperature change and heat dissipation.

[0042] For example, if the ambient temperature rises during testing, the temperature difference between the icing wire and the surrounding air will decrease, leading to an underestimation of the intensity of natural convection heat transfer, and possibly even masking the full thermal response characteristics caused by current heating.

[0043] For example, if the ambient temperature decreases, it will enhance the uncontrolled heat dissipation effect, making the measured temperature decay rate unable to accurately reflect the energy balance between the conductor's own heat generation and the icing phase change. If only temperature data collected under non-isothermal conditions is used to invert the natural convection heat transfer coefficient, false thermal gradients introduced by environmental disturbances will be mixed in, leading to misjudgments of the icing thermodynamic behavior.

[0044] Therefore, static convection heat transfer tests must be initiated while maintaining a constant ambient temperature to isolate external thermal interference factors and ensure that the obtained surface temperature evolution data is dominated only by Joule heating of the conductor and icing phase change, thus providing a reliable basis for subsequent accurate calculation of natural convection heat transfer coefficient and cumulative heat dissipation.

[0045] S104 synchronously acquires temperature data output from the infrared temperature measurement array until the temperature at any measurement point reaches zero degrees Celsius. In actual operation, the surface temperature of the icing conductor rises non-uniformly during the current heating process. This non-uniformity is closely related to the ice thickness distribution, circumferential convection intensity, and the conductor's own thermal conductivity.

[0046] If the temperature rise is delayed at the upper measuring point of a certain temperature measurement section due to weak natural convection, the other positions or adjacent sections may have already approached or reached the freezing point. If heating continues without timely termination of data acquisition, it will cause the local ice to melt prematurely, destroy the integrity of the ice phase interface during the test, and may even cause thermal measurement distortion.

[0047] Conversely, if data acquisition is stopped before all measuring points reach zero degrees Celsius, the key thermal response characteristics before the icing phase change cannot be captured, resulting in a lack of effective data. If data acquisition is terminated uniformly based solely on a preset heating time or a fixed temperature threshold, without using the actual temperature at the measuring points as a criterion, the difference in thermal state between the circumferential and axial directions of the icing conductor will be ignored, leading to misjudgment of the critical stage of the natural convection heat transfer process.

[0048] Therefore, it is necessary to simultaneously collect temperature data output from the infrared temperature measurement array until the temperature at any measurement point reaches zero degrees Celsius, in order to ensure a complete record of the entire thermal evolution process from initial heating to the critical point of icing phase transition, while avoiding interference with the accuracy of subsequent thermal parameter inversion due to local icing melting.

[0049] S105, Calculate the curve of the average temperature of the ice-covered surface changing over time based on the collected temperature data; In an embodiment of the present invention, calculating the curve of the average temperature of the icy surface changing over time includes: The arithmetic mean of the temperature values ​​output by all infrared temperature measurement units at each sampling time is used to form the average temperature of the icy surface at that time. The average surface temperature of the ice-covered area at each time point was then plotted as a curve in chronological order.

[0050] It is worth noting that during the current heating process of the icing conductor, due to the difference in circumferential natural convection intensity and the uneven axial ice layer thickness, the temperature values ​​output by each temperature measuring unit at the same moment have significant spatial dispersion. If this dispersion is not effectively integrated, it is impossible to accurately characterize the overall thermal state evolution law of the icing.

[0051] In some embodiments, calculating the curve of the average temperature of the icy surface changing over time specifically includes the following steps: Initially, the temperature values ​​output by the four directional infrared temperature measurement units within all temperature measurement sections at each sampling moment are synchronously acquired from the infrared temperature measurement array. Each temperature measurement unit corresponds to a fixed spatial position, and all temperature measurement units maintain a consistent sampling frequency throughout the test.

[0052] Furthermore, for each sampling moment, the temperature values ​​output by all infrared temperature measurement units at that moment are arithmetically averaged to generate a single value representing the overall thermal level of the icy surface at that moment, i.e., the average temperature of the icy surface at that moment.

[0053] Furthermore, the average surface temperature of the ice-covered surfaces corresponding to all sampling times is arranged in chronological order to form a time-temperature data sequence.

[0054] Furthermore, by plotting time on the x-axis and the average temperature of the icy surface on the y-axis, the aforementioned time-temperature data sequence is plotted as a continuous curve, representing the complete thermal evolution trajectory of the average temperature of the icy surface over time.

[0055] It should be noted that the infrared temperature measurement arrays mentioned above include, but are not limited to, FLIR A655sc, Testo890, or self-developed multi-channel infrared sensing modules.

[0056] It should be noted that the infrared temperature measurement unit mentioned above can be understood as a non-contact thermal sensing element used in this invention to capture the temperature of a specific location on the surface of an icy conductor in real time.

[0057] The temperature measurement section can be understood as a spatial sampling plane arranged along the axial direction of the icing conductor in this invention to characterize the local thermal state.

[0058] It should be noted that the average temperature of the icing surface can be understood as a key thermodynamic parameter used in this invention to eliminate the influence of circumferential and axial temperature non-uniformity and to reflect the overall thermal response level of the icing.

[0059] It should also be noted that the curve of the average temperature of the ice-covered surface changing over time can be understood as the basic input data structure used in this invention to support the inversion of the natural convection heat transfer coefficient and the calculation of cumulative heat dissipation.

[0060] S106, based on the average temperature curve of the ice-covered surface, ambient temperature and air physical parameters, sequentially calculate the dimensionless product of natural convection intensity, natural convection Nusselt number, natural convection heat transfer coefficient of the outer surface of the ice layer, equivalent natural convection heat dissipation thermal resistance per unit length of conductor, natural convection heat flux per unit length of conductor, and cumulative heat loss per unit length of conductor through natural convection during the test.

[0061] In an embodiment of the present invention, calculating the dimensionless product characterizing the intensity of natural convection includes: The numerators are gravitational acceleration, the cube of the difference between the average temperature of the ice-covered surface and the ambient temperature, the specific heat capacity of air, and the aerodynamic viscosity. The ratio calculated by using the square of the kinematic viscosity of air and the thermal conductivity of air as the denominator is the product of dimensionless numbers.

[0062] It is worth noting that during the natural convection heat transfer process of the icing conductor, the heat transfer intensity is affected by both the buoyancy force and the air physical properties. This relationship needs to be quantitatively characterized by dimensionless multiplication to establish a physical mapping between the average temperature of the icing surface and the heat dissipation.

[0063] When the average temperature of the ice-covered surface is significantly higher than the ambient temperature, the buoyancy driven by the temperature difference is enhanced, which leads to an increase in the natural convection heat transfer coefficient. If the coupling effect of physical properties such as aerodynamic viscosity, kinematic viscosity and thermal conductivity on the flow boundary layer and thermal boundary layer is ignored, the actual heat transfer state cannot be accurately reflected, and it may even cause serious deviations in the prediction of the ice melting process.

[0064] Conversely, if the average temperature of the icing surface is close to the ambient temperature, the buoyancy is weak, and natural convection tends to stagnate. In this case, if a forced convection model or a simplified linear temperature difference relationship is still used for estimation, the actual heat dissipation will be overestimated. If only a single temperature difference or local wind speed is used as the heat transfer criterion, without constructing a complete dimensionless correlation that includes gravitational acceleration, the cube of the temperature difference, air specific heat capacity, dynamic viscosity, kinematic viscosity, and thermal conductivity, the nonlinear coupling mechanism between buoyancy and fluid transport characteristics will be lost, leading to a misjudgment of the natural convection heat transfer coefficient.

[0065] Therefore, it is necessary to use gravitational acceleration, the cube of the difference between the average input temperature of the ice-covered surface and the ambient temperature, the specific heat capacity of air and the dynamic viscosity of air as the numerator, and the square of the kinematic viscosity of air and the thermal conductivity of air as the denominator. The calculated ratio is the dimensionless product, which can accurately characterize the combined effect between buoyancy and fluid thermal properties in the natural convection heat transfer process, and provide a theoretical basis for the subsequent inversion of the heat transfer coefficient.

[0066] In an embodiment of the present invention, the step of calculating the natural convection Nusselt number includes: Take the natural logarithm of the product of dimensionless numbers that characterize the intensity of natural convection; Multiply the result by the first fitting coefficient and add the second fitting coefficient to obtain the natural convection Nusselt number. The first and second fitting coefficients were determined through experimental calibration.

[0067] It should be pointed out that in actual operation, there is a nonlinear power law relationship between the natural convection Nusselt number and the dimensionless number product that characterizes the coupling effect of buoyancy and fluid properties. If this relationship is directly fitted by the original dimensionless number product, the regression model will have difficulty converging and poor generalization ability due to the large numerical range and serious distribution skew.

[0068] When the dimensionless number product changes across multiple orders of magnitude, it signifies a transition from weak to strong convection in natural convection, leading to a significant reconfiguration of the thermal boundary layer structure. Therefore, a logarithmic transformation of the dimensionless number product is necessary, along with the introduction of linear fitting parameters to establish a stable and reliable Nusselt number prediction model.

[0069] In some embodiments, the natural logarithm of the dimensionless product characterizing the intensity of natural convection can be taken; the result is then multiplied by a first fitting coefficient and added to a second fitting coefficient to obtain the natural convection Nusselt number. That is, after completing the static convection heat transfer test and obtaining the average temperature curve of the icing surface, a dimensionless product is first constructed based on the aforementioned numerator and denominator terms, then its natural logarithm is taken to compress the dynamic range, and finally mapped to the Nusselt number space through a linear transformation.

[0070] For example, in a heating experiment of an iced wire, the product of dimensionless numbers was calculated to be 2.8 × 10⁻⁶. 6 The natural logarithm is 14.85. If the first fitting coefficient is 0.28 and the second fitting coefficient is 1.12, then the obtained natural convection Nusselt number is 5.28.

[0071] If experimental data obtained under different ambient temperatures or wire diameters exhibit systematic deviations, the first and second fitting coefficients need to be independently calibrated for each set of conditions. For example, in the test group with an ambient temperature of -10 degrees Celsius and a wire diameter of 26.8 mm, the fitting coefficients are 0.27 and 1.15, respectively; while under the condition of an ambient temperature of -5 degrees Celsius and the same wire diameter, the fitting coefficients are adjusted to 0.29 and 1.09 to compensate for the influence of changes in air properties with temperature.

[0072] After completing the above logarithmic linear fitting operation based on experimental calibration, the convective heat transfer coefficient of the icing conductor surface can be accurately inverted based on the obtained natural convection Nusselt number, thereby supporting the accurate calculation of cumulative heat dissipation.

[0073] Among them, the dimensionless product of the above-mentioned characterizing natural convection intensity refers to the dimensionless combination of the numerator consisting of gravitational acceleration, the cube of the difference between the average temperature of the ice-covered surface and the ambient temperature, the specific heat capacity of air and the dynamic viscosity of air, and the denominator consisting of the square of the kinematic viscosity of air and the thermal conductivity of air.

[0074] The first fitting coefficient refers to the calibration parameter used to adjust the slope of the logarithmic domain to match the trend of the experimental data.

[0075] The second fitting coefficient is a calibration parameter used to correct the logarithmic domain intercept to ensure the accuracy of the Nusselt number reference value; the natural convection Nusselt number is a core thermodynamic parameter that reflects the dimensionless convective heat transfer intensity on the surface of the icing conductor.

[0076] In this embodiment of the invention, the step of calculating the natural convection heat flux per unit length of conductor includes: Multiply by pi, the outer diameter of the ice-covered conductor, and the natural convection heat transfer coefficient of the outer surface of the ice layer; Multiplying this by the difference between the average temperature of the ice-covered surface and the ambient temperature, we obtain the natural convection heat flow per unit length of conductor at the corresponding moment.

[0077] In practice, the amount of natural convection heat dissipation per unit length of the icing conductor during the heating and melting process directly determines the accuracy of the energy balance calculation. This heat dissipation is closely related to the heat exchange area of ​​the outer surface of the ice layer, the natural convection heat transfer coefficient, and the temperature difference between the icing surface and the environment.

[0078] When an ice-covered conductor is in a state of strong natural convection and the average temperature of the ice surface is significantly higher than the ambient temperature, the heat loss per unit length of conductor to the surrounding air will increase dramatically. If the actual heat exchange perimeter determined by the outer diameter of the ice layer is not accurately taken into account, the total heat dissipation power will be underestimated, and it may even lead to an incorrect setting of the required de-icing current, resulting in incomplete de-icing or energy waste.

[0079] Conversely, if the average temperature of the ice-covered surface is close to the ambient temperature, natural convection heat dissipation is weak. In this case, if the heat transfer area is calculated using the diameter of the conductor's metal core instead of the outer surface diameter of the ice layer, the effective heat dissipation capacity will be overestimated. If the heat dissipation is estimated using only simplified formulas or fixed heat transfer coefficients without combining real-time inverted natural convection heat transfer coefficients, accurate ice layer outer diameters, and instantaneous temperature differences for dynamic calculation, systematic thermal balance errors will be introduced, leading to misjudgments of cumulative heat dissipation and the ice melting process.

[0080] Therefore, it is necessary to multiply the pi, the outer diameter of the icing conductor, and the natural convection heat transfer coefficient of the outer surface of the ice layer, and then multiply by the difference between the average temperature of the icing surface and the ambient temperature to obtain the natural convection heat flow per unit length of conductor at the corresponding time, thereby achieving high-precision dynamic quantification of the heat loss of the icing conductor.

[0081] In an embodiment of the present invention, the step of calculating the cumulative heat lost by natural convection per unit length of conductor during the test includes: Multiply the natural convection heat flux calculated at each sampling time by the sampling time interval; The cumulative heat is obtained by summing the multiplications accumulated over all sampling times.

[0082] It should be noted that in actual operation, the heat flow of the icing conductor during the heating process changes continuously with time due to natural convection. If this dynamic heat flow is not accumulated through time integration, it cannot accurately reflect the total energy lost by the conductor to the environment from the start of heating to the critical point of phase change.

[0083] For example, in low temperature and high humidity environments, the surface temperature rises slowly in the early stages of icing, and the heat flow from natural convection is small but lasts for a long time. If only a certain instantaneous heat flow value is taken or the average heat flow is used to approximate the total heat dissipation, the actual cumulative heat dissipation will be seriously underestimated, and it may even lead to insufficient ice melting current setting, resulting in ice melting failure or prolonged power outage time.

[0084] For example, if the rate of temperature rise accelerates near zero degrees Celsius, the natural convective heat flux increases rapidly, but this duration is short. If only the arithmetic mean of the heat flux at the beginning and end times is multiplied by the total duration for estimation, the high contribution range during the nonlinear growth of heat flux will be ignored, leading to a misjudgment of the required input electrical energy.

[0085] Therefore, the natural convection heat flow calculated at each sampling moment can be multiplied by the sampling time interval, and the cumulative heat can be obtained by summing the multiplications at all sampling moments, thereby achieving accurate quantification of the total energy lost by the icing conductor to the environment throughout the entire heating process.

[0086] Example 2, see Figure 2~ Figure 10 Based on the above embodiments, the specific implementation of a calculation model and testing method for static convective heat transfer on the surface of an icing conductor can be designed as follows: Specifically, ice-covered wires, an infrared temperature measurement array, and a test power supply are arranged inside the cold storage, as shown in Figure 2(a).

[0087] The length of the icing conductor is L (L=1.0m); the icing thickness is r2 (r2=10mm); the test power supply outputs at both ends of the conductor, and the output current of the test power supply is used to adjust the temperature of the icing surface; an infrared temperature measurement unit is arranged in each of the four directions (up, down, left, and right) of the icing conductor every 0.1m, as shown in Figure 2(b).

[0088] Furthermore, we prepared formulas for the natural convection heat exchange coefficient of the outer surface of the ice layer, the product formula of Prandtl number and Grashof number, and the logarithmic function fitting formula for the natural convection Nusselt number. While keeping the ambient temperature constant, we conducted static convection heat transfer tests.

[0089] Furthermore, a formula for the natural convection heat exchange coefficient of the outer surface of the ice layer is prepared. The expression for the natural convection heat exchange coefficient of the outer surface of the ice layer is as follows: (1) In the formula, h is the natural convection heat exchange coefficient of the outer surface of the ice layer, W / (m²). 2‧℃); λ is the thermal conductivity of air, λ=0.0244W / (m‧℃); N represents the Nusselt number of natural convection for the icy conductor (dimensionless); X is the product of Prandtl number and Grashof number (dimensionless); r1 is the outer radius of the conductor, m; r2 is the thickness of the ice layer, m.

[0090] Furthermore, let's prepare the formula for the Prandtl number-Grashof number product. The expression for the Prandtl number-Grashof number product is: (2) In the formula: T and T0 are the outer surface temperature of the ice layer (°C) and the ambient temperature (°C), respectively; g is the gravitational constant (m / s²). 2 g = 9.8; ν is the kinematic viscosity of air (m³ / s). 2 / s), ν=1.328×10 -5 μ is the kinetic viscosity of air (kg / (m‧s)), μ=1.72×10 -5 C is the specific heat capacity of air (J / kg·℃), C=1005, such as Figure 3 The figure shown is an example of the Prandtl number-Grashof number product versus the outer surface temperature of the ice layer with respect to the ambient temperature difference.

[0091] Furthermore, a functional fitting formula for the natural convection Nusselt number is prepared. The product of the Prandlt number and the Grashof number has a natural logarithmic functional fitting relationship with the natural convection Nusselt number. Specifically, the formula for calculating the natural convection Nusselt number is: (3) (4) In the formula: ln is the natural logarithm function; x is the natural logarithm of X, such as Figure 4 The figure shown is an example of the relationship between the natural convection Nusselt number and the outer surface temperature of the ice layer with respect to the ambient temperature difference.

[0092] Furthermore, the test power supply is prepared to apply a test current to the icy conductor, and the test current is determined according to the following formula: (5) In the formula: C is the test current (A); S is the cross-sectional area of ​​the conductor (mm²). 2 ).

[0093] Furthermore, the ambient temperature T0 is recorded, and the ambient temperature is kept constant during the measurement process.

[0094] Furthermore, record the ice-covered surface temperature data until any infrared temperature measurement reading reaches 0°C, and compile the average temperature curve of the ice-covered surface by setting a set of data per second.

[0095] Furthermore, each infrared temperature measurement unit records the temperature change of the iced conductor surface during the de-icing process at a rate of one data point per second, saves the data to a computer, and summarizes it into an average surface temperature of the icing: (6) In the formula: Θk is the reading of the infrared temperature measurement unit numbered k (°C); t is time (s); T1 is the average temperature of the icy surface (°C), such as Figure 5 The figure shows the average temperature curve of the icy surface during the test.

[0096] Furthermore, by analyzing the average temperature curve of the ice-covered surface, the static convective heat transfer coefficient during the temperature rise process is calculated.

[0097] Furthermore, by updating the Prandlt number-Grashof number product using the average temperature curve data of the icy surface, the Prandlt number-Grashof number product curve is obtained.

[0098] Substituting equation (6) into (2), the formula for calculating the Prandtl number-Grashof number product curve is: (7) like Figure 6 The figure shows the Prandtl number-Grashof number product curve during the test period.

[0099] Furthermore, the Nusselt number curve is derived from the Prandtl number-Grashof number product curve.

[0100] Substituting equation (7) into equation (4), we get: (8) Substituting equation (8) into equation (3) yields the Nusselt number curve: (9) like Figure 7 The figure shows the Nusselt number curve during the test period.

[0101] Furthermore, the natural convection heat exchange coefficient curve of the outer surface of the ice layer was calculated.

[0102] Substituting equation (9) into equation (1), the formula for calculating the natural convection heat exchange coefficient curve of the outer surface of the ice layer is: (10) Furthermore, the equivalent natural convection heat dissipation resistance per unit length of conductor is calculated.

[0103] Equivalent natural convection heat dissipation resistance R per unit length of wire h The calculation formula is: (11) like Figure 8 The diagram shows the equivalent natural convection resistance during the test.

[0104] Furthermore, the heat flux dissipated by natural convection per unit length of conductor during the temperature rise process is calculated.

[0105] Substituting equation (9) into equation (1) yields the natural convection heat flux curve per unit length of conductor, and the calculation formula is: (12) like Figure 9 The heat flux curve for natural convection heat dissipation per unit length of wire during the test is shown.

[0106] Furthermore, the cumulative heat loss due to natural convection during the temperature rise process is calculated.

[0107] Integrating equation (12), we obtain the cumulative heat loss due to natural convection: (13) In the formula: Q h The cumulative heat loss per unit length of conductor due to natural convection (J / m); t max Let be the test end time (s). Since the sampling rate of all test data is 1s, equation (13) can be equivalently transformed into: (14) like Figure 10 The curve shows the cumulative heat dissipation per unit length of conductor during the test, induced by natural convection.

[0108] It should be noted that, compared with traditional methods of ice melting analysis that rely on empirical estimation or single parameter calculation, this calculation model and testing system not only clearly defines the magnitude of natural convection heat dissipation for the first time (approximately 5-20% of the forced convection heat dissipation caused by wind speed), but also fills the gap in the lack of dedicated testing methods and accurate calculation models for static convection heat transfer on the surface of iced conductors. This effectively makes up for the limitations of existing technologies that cannot fully capture the core parameters of heat transfer and cannot accurately support the optimization of ice melting power and duration.

[0109] Example 3, referring to Figure 11 This embodiment also provides a calculation model and testing system for static convective heat transfer on the surface of an icing conductor, including: Temperature-controlled environment chamber, used to provide a testing space with a constant ambient temperature; The ice-covered conductor is installed inside the temperature-controlled environment chamber and its surface is covered with a uniform layer of ice. The test power supply, connected to both ends of the ice-covered wire, is used to apply current to the ice-covered wire to regulate the temperature of the ice-covered surface; An infrared temperature measurement array is arranged around the icing conductor to simultaneously collect temperature data at multiple locations on the surface of the icing conductor during the test until the temperature at any measuring point reaches zero degrees Celsius. The data processing unit, which is communicatively connected to the infrared temperature measurement array, is used to receive temperature data and perform the following operations: calculate the curve of the average temperature of the ice-covered surface changing over time; and based on the curve, ambient temperature, and air properties, sequentially calculate the dimensionless product of natural convection intensity, the natural convection Nusselt number, the natural convection heat transfer coefficient of the outer surface of the ice layer, the equivalent natural convection heat dissipation thermal resistance per unit length of the conductor, the natural convection heat flux per unit length of the conductor, and the cumulative heat lost by the conductor per unit length through natural convection during the test.

[0110] The above-mentioned unit modules can be embedded in the processor of the electronic device in hardware form or independent of it, or they can be stored in the memory of the electronic device in software form, so that the processor can call and execute the corresponding operations of the above modules.

[0111] This embodiment also provides an electronic device, which can be a terminal, and its internal structure diagram can be as follows: Figure 11 As shown, the electronic device includes a processor, memory, communication interface, display screen, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, carrier networks, NFC (Near Field Communication), or other technologies. When the computer program is executed by the processor, it implements a calculation model and test method for static convection heat transfer on the surface of an icing conductor. The display screen can be an LCD screen or an e-ink screen. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the device's casing, or an external keyboard, touchpad, or mouse.

[0112] This embodiment also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed by a processor, it performs the following steps: Arrange the ice-covered wires, infrared temperature measurement array, and test power supply in a temperature-controlled environment; The temperature of the ice-covered surface is adjusted by applying current to the ice-covered wire using a test power source. The static convection heat transfer test was initiated while maintaining a constant ambient temperature. Simultaneously acquire temperature data output from the infrared temperature measurement array until the temperature at any measuring point reaches zero degrees Celsius; The curve of the average temperature of the ice-covered surface changing over time was calculated based on the collected temperature data; Based on the average temperature curve of the ice-covered surface, ambient temperature, and air properties, the dimensionless product of natural convection intensity, the natural convection Nusselt number, the natural convection heat transfer coefficient of the outer surface of the ice layer, the equivalent natural convection heat dissipation thermal resistance per unit length of the conductor, the natural convection heat flux per unit length of the conductor, and the cumulative heat lost by the conductor per unit length of the conductor through natural convection during the test are calculated sequentially.

[0113] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

[0114] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0115] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A calculation model and testing method for static convective heat transfer on the surface of an icing conductor, characterized in that, include: Arrange the ice-covered wires, infrared temperature measurement array, and test power supply in a temperature-controlled environment; The temperature of the ice-covered surface is adjusted by applying current to the ice-covered wire using a test power source. The static convection heat transfer test was initiated while maintaining a constant ambient temperature. Simultaneously acquire temperature data output from the infrared temperature measurement array until the temperature at any measuring point reaches zero degrees Celsius; The curve of the average temperature of the ice-covered surface changing over time was calculated based on the collected temperature data; Based on the average temperature curve of the ice-covered surface, ambient temperature, and air properties, the dimensionless product of natural convection intensity, the natural convection Nusselt number, the natural convection heat transfer coefficient of the outer surface of the ice layer, the equivalent natural convection heat dissipation thermal resistance per unit length of the conductor, the natural convection heat flux per unit length of the conductor, and the cumulative heat lost by the conductor per unit length of the conductor through natural convection during the test are calculated sequentially.

2. The calculation model and testing method for static convective heat transfer on the surface of an icing conductor as described in claim 1, characterized in that, The arrangement of the icing wires, infrared temperature measurement array, and infrared temperature measurement array in the test power supply in a temperature-controlled environment includes: Multiple temperature measurement sections are set along the length of the icing conductor. Each temperature measurement section has four infrared temperature measurement units evenly arranged in the circumference, corresponding to the upper, lower, left, and right directions respectively.

3. The calculation model and testing method for static convective heat transfer on the surface of an icing conductor as described in claim 2, characterized in that, The curve for calculating the average temperature of the icy surface over time includes: The arithmetic mean of the temperature values ​​output by all infrared temperature measurement units at each sampling time is used to form the average temperature of the icy surface at that time. The average surface temperature of the ice-covered area at each time point was then plotted as a curve in chronological order.

4. The calculation model and testing method for static convective heat transfer on the surface of an icing conductor as described in claim 3, characterized in that, The calculation of the dimensionless product characterizing the intensity of natural convection includes: The numerators are gravitational acceleration, the cube of the difference between the average temperature of the ice-covered surface and the ambient temperature, the specific heat capacity of air, and the aerodynamic viscosity. The ratio calculated by using the square of the air kinematic viscosity and the air thermal conductivity as the denominator is the product of the dimensionless numbers.

5. The calculation model and testing method for static convective heat transfer on the surface of an icing conductor as described in claim 4, characterized in that, The steps for calculating the natural convection Nusselt number include: Take the natural logarithm of the dimensionless product of the dimensions representing the intensity of natural convection; Multiply the result by the first fitting coefficient and add the second fitting coefficient to obtain the natural convection Nusselt number. The first and second fitting coefficients were determined through experimental calibration.

6. The calculation model and testing method for static convective heat transfer on the surface of an icing conductor as described in claim 5, characterized in that, The steps for calculating the natural convection heat flux per unit length of the conductor include: Multiply by pi, the outer diameter of the ice-covered conductor, and the natural convection heat transfer coefficient of the outer surface of the ice layer; Multiplying this by the difference between the average temperature of the ice-covered surface and the ambient temperature, we obtain the natural convection heat flow per unit length of conductor at the corresponding moment.

7. The calculation model and testing method for static convective heat transfer on the surface of an icing conductor as described in claim 6, characterized in that, The steps for calculating the cumulative heat loss per unit length of conductor during the test via natural convection include: Multiply the natural convection heat flux calculated at each sampling time by the sampling time interval; The cumulative heat is obtained by summing the multiplications accumulated over all sampling times.

8. A calculation model and testing system for static convective heat transfer on the surface of an icing conductor, using the method described in any one of claims 1 to 7, characterized in that, include: Temperature-controlled environment chamber, used to provide a testing space with a constant ambient temperature; The ice-covered conductor is installed inside the temperature-controlled environment chamber and its surface is covered with a uniform layer of ice. The test power supply, connected to both ends of the ice-covered wire, is used to apply current to the ice-covered wire to regulate the temperature of the ice-covered surface; An infrared temperature measurement array is arranged around the icing conductor to simultaneously collect temperature data at multiple locations on the surface of the icing conductor during the test until the temperature at any measuring point reaches zero degrees Celsius. The data processing unit, which is communicatively connected to the infrared temperature measurement array, is used to receive temperature data and perform the following operations: calculate the curve of the average temperature of the ice-covered surface changing over time; and based on the curve, ambient temperature, and air properties, sequentially calculate the dimensionless product of natural convection intensity, the natural convection Nusselt number, the natural convection heat transfer coefficient of the outer surface of the ice layer, the equivalent natural convection heat dissipation thermal resistance per unit length of the conductor, the natural convection heat flux per unit length of the conductor, and the cumulative heat lost by the conductor per unit length through natural convection during the test.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the calculation model and test method for static convective heat transfer on the surface of an icing conductor as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the calculation model and test method for static convective heat transfer on the surface of an icing conductor as described in any one of claims 1 to 7.

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