A numerical method for the analysis of the electrothermal deicing system for an airfoil is developed taking into account mass and heat exchange at the moving boundary that separates the water film created due to dropl...A numerical method for the analysis of the electrothermal deicing system for an airfoil is developed taking into account mass and heat exchange at the moving boundary that separates the water film created due to droplet impingement and the ice accretion region.The method relies on a Eulerian approach(used to capture droplet dynamics)and an unsteady heat transfer model(specifically conceived for a multilayer electrothermal problem on the basis of the enthalpy theory and a phase-change correction approach).Through application of the continuous boundary condition for temperature and heat flux at the coupled movingboundary,several simulations of ice accretion,melting and shedding,runback water flow and refreezing phenomena during the electrothermal deicing process are conducted.Finally,the results are verified via comparison with experimental data.A rich set of data concerning the dynamic evolution of the distribution of surface temperature,water film height and ice shape is presented and critically discussed.展开更多
The deicing experiment of carbon fiber reinforced electrically conductive concrete (CFRC) slab was conducted in laboratory at first, then the deicing process of CFRC parement was analyzed by means of finite elemen...The deicing experiment of carbon fiber reinforced electrically conductive concrete (CFRC) slab was conducted in laboratory at first, then the deicing process of CFRC parement was analyzed by means of finite element method (FEM). At last, based on the energy conservation law and the computing restdts of finite element method, the influential factors including the setting of electric heating layer, environmental temperature, the thickness of ice, material parameters, and deicing power on deicing performance and energy consumption were discussed.展开更多
Carbon fiber reinforced concrete (CFRC) is a kind of good electrothermal material. When connected to an external power supply, stable and uniform heat suitable for deicing application is generated in the CFRC slab. El...Carbon fiber reinforced concrete (CFRC) is a kind of good electrothermal material. When connected to an external power supply, stable and uniform heat suitable for deicing application is generated in the CFRC slab. Electric heating and deicing experiments of carbon fiber reinforced concrete slab were carried out in laboratory, and the effect of the temperature and thickness of ice, the thermal conductivity of CFRC, and power output on deicing performance and energy consumption were investigated. The experimental results indicate that it is an effective method to utilize the thermal energy produced by CFRC slab to deice. The time to melt the ice completely decreases with increasing power output and ice temperature, and increases with increasing thickness of the ice. The energy consumption to melt 2 mm thickness of ice varies approximately linearly from 0.556 to 0.846 kW·h/m2 as the initial temperature ranges from -3℃ to - 18℃. CFRC with good thermal conduction can reduce temperature difference in CFRC slab effectively.展开更多
Carbon/glass fiber hybrid textile reinforced concrete is a relatively new composite material with good mechanical capacity and excellent electrical conductivity.Both small-scale slab heating experiments and numerical ...Carbon/glass fiber hybrid textile reinforced concrete is a relatively new composite material with good mechanical capacity and excellent electrical conductivity.Both small-scale slab heating experiments and numerical simulation are presented in this paper.Temperature variation curves obtained during heating indicate the effects of environmental temperature,heat-conducting layer thickness and electric heating power.Comparison of temperature rising between the situations with and without thermal isolation layer is given as well.The results indicate that the textile can form a good conductive heating network and generate enough heat to raise the temperature in the concrete when connected to a power supply,while the resistance of the slab remains stable during the heating.Numerical results are in good accordance with the experiments.Real time snow-melting experiment was conducted to verify the feasibility of deicing.The electrothermal properties of textile can be utilized for deicing and snow melting in a safe,environmentally friendly and efficient way.展开更多
Icing on the surface of aircraft will not only aggravate its quality and affect flight control,but even cause safety accidents,which is one of the important factors restricting all-weather flight.Bio-inspired anti-ici...Icing on the surface of aircraft will not only aggravate its quality and affect flight control,but even cause safety accidents,which is one of the important factors restricting all-weather flight.Bio-inspired anti-icing surfaces have gained great attention recently due to their low-hysteresis,non-stick properties,slow nucleation rate and low ice adhesion strength.These bio-inspired anti-icing surfaces,such as superhydrophobic surfaces,slippery liquid-infused porous surfaces and quasi-liquid film surfaces,have realized excellent anti-icing performance at various stages of icing.However,for harsh environment,there are still many problems and challenges.From the perspective of bioinspiration,the mechanism of icing nucleation,liquid bounce and ice adhesion has been reviewed together with the application progress and bottleneck issues about anti-icing in view of the process of icing.Subsequently,the reliability and development prospect of active,passive and active-passive integrated anti-icing technology are discussed,respectively.展开更多
Literature has demonstrated that Carbon Nanotubes(CNTs) can greatly enhance the electrical conductivity and matrix-dominated mechanical properties of fibrous composites. However, electrothermal coupling effect of CNTs...Literature has demonstrated that Carbon Nanotubes(CNTs) can greatly enhance the electrical conductivity and matrix-dominated mechanical properties of fibrous composites. However, electrothermal coupling effect of CNTs on Carbon Fiber Reinforced Plastics(CFRPs) has scarcely been considered. This work prepared and introduced thin and porous CNT webs to the surface or/and interface of a CFRP to enhance its electrothermal properties. The results show that CNT webs can enhance the transverse electrical conductivities of the CFRP by 231%-519% in a current range of 50–150mA, when compared to the base-CFRP. Also, the surface temperature of CNT webs decorated CFRP can be improved by 20.5–32.3℃ within 3min showing a self-heating rate of 6.8–10.8℃/min just with an applied voltage of 20–30V, increased by 152%-177% when compared to the base-CFRP(2.7–3.9℃/min). Also, deicing can be finished within 4–10min with a voltage of 18V and an input power of 246W/m^(2). Moreover, the electrothermal processes nearly have no negative effect on the mechanical properties of the CFRP. The relatively low input power and short response time for deicing make the CNT webs decorated CFRP may be a potential new generation for aeronautical deicing structure.展开更多
Solar anti-icing/de-icing is an environmentally friendly way to convert light energy into heat with the purpose of melting/removing ice. However, the inherent intermittency of solar irradiation limits the application ...Solar anti-icing/de-icing is an environmentally friendly way to convert light energy into heat with the purpose of melting/removing ice. However, the inherent intermittency of solar irradiation limits the application of solar-thermal energy-conversion technologies, when continuous de-icing is required. Herein, we investigate a solar phase-change material(SPCM) that consists of expanded graphite(EG)/paraffin/polydimethylsiloxane(PDMS), which can not only perform the solar-thermal conversion but also release/store thermal energy. Under sunlight, the SPCM effectively collects and converts the light energy into thermal energy for later antiicing/de-icing. To prepare for a no-light period, e.g., in the evening, the converted thermal energy can be stored in the SPCM using a phase transition. In this way, the energy can be released when needed to keep the temperature of a surface from freezing. The SPCM surface shows excellent anti-icing/de-icing properties such as a long droplet freeze-delay time(td> 2 h), even at an ultra-low temperature(-40℃), using only the light of one sun. This freeze-delay time is much longer than that for a surface without PCM. The tested SPCM surfaces show a high de-icing rate(2.21 kg m^(-2)h^(-1)) under real-life conditions. In addition, the SPCM shows a high de-icing rate and excellent durability. This study provides a promising route for the utilization of solar energy in anti-icing/de-icing applications.展开更多
基金supported by Rotor Aerodynamics Key Laboratory[Grant Number RAL20180401].
文摘A numerical method for the analysis of the electrothermal deicing system for an airfoil is developed taking into account mass and heat exchange at the moving boundary that separates the water film created due to droplet impingement and the ice accretion region.The method relies on a Eulerian approach(used to capture droplet dynamics)and an unsteady heat transfer model(specifically conceived for a multilayer electrothermal problem on the basis of the enthalpy theory and a phase-change correction approach).Through application of the continuous boundary condition for temperature and heat flux at the coupled movingboundary,several simulations of ice accretion,melting and shedding,runback water flow and refreezing phenomena during the electrothermal deicing process are conducted.Finally,the results are verified via comparison with experimental data.A rich set of data concerning the dynamic evolution of the distribution of surface temperature,water film height and ice shape is presented and critically discussed.
文摘The deicing experiment of carbon fiber reinforced electrically conductive concrete (CFRC) slab was conducted in laboratory at first, then the deicing process of CFRC parement was analyzed by means of finite element method (FEM). At last, based on the energy conservation law and the computing restdts of finite element method, the influential factors including the setting of electric heating layer, environmental temperature, the thickness of ice, material parameters, and deicing power on deicing performance and energy consumption were discussed.
基金This work was supported by the key project of National Natural Science Foundation of China under grant No.50238040.
文摘Carbon fiber reinforced concrete (CFRC) is a kind of good electrothermal material. When connected to an external power supply, stable and uniform heat suitable for deicing application is generated in the CFRC slab. Electric heating and deicing experiments of carbon fiber reinforced concrete slab were carried out in laboratory, and the effect of the temperature and thickness of ice, the thermal conductivity of CFRC, and power output on deicing performance and energy consumption were investigated. The experimental results indicate that it is an effective method to utilize the thermal energy produced by CFRC slab to deice. The time to melt the ice completely decreases with increasing power output and ice temperature, and increases with increasing thickness of the ice. The energy consumption to melt 2 mm thickness of ice varies approximately linearly from 0.556 to 0.846 kW·h/m2 as the initial temperature ranges from -3℃ to - 18℃. CFRC with good thermal conduction can reduce temperature difference in CFRC slab effectively.
文摘Carbon/glass fiber hybrid textile reinforced concrete is a relatively new composite material with good mechanical capacity and excellent electrical conductivity.Both small-scale slab heating experiments and numerical simulation are presented in this paper.Temperature variation curves obtained during heating indicate the effects of environmental temperature,heat-conducting layer thickness and electric heating power.Comparison of temperature rising between the situations with and without thermal isolation layer is given as well.The results indicate that the textile can form a good conductive heating network and generate enough heat to raise the temperature in the concrete when connected to a power supply,while the resistance of the slab remains stable during the heating.Numerical results are in good accordance with the experiments.Real time snow-melting experiment was conducted to verify the feasibility of deicing.The electrothermal properties of textile can be utilized for deicing and snow melting in a safe,environmentally friendly and efficient way.
基金financially supported by the National Natural Science Foundation of China(Nos.T2121003,51725501,51935001,52205297).
文摘Icing on the surface of aircraft will not only aggravate its quality and affect flight control,but even cause safety accidents,which is one of the important factors restricting all-weather flight.Bio-inspired anti-icing surfaces have gained great attention recently due to their low-hysteresis,non-stick properties,slow nucleation rate and low ice adhesion strength.These bio-inspired anti-icing surfaces,such as superhydrophobic surfaces,slippery liquid-infused porous surfaces and quasi-liquid film surfaces,have realized excellent anti-icing performance at various stages of icing.However,for harsh environment,there are still many problems and challenges.From the perspective of bioinspiration,the mechanism of icing nucleation,liquid bounce and ice adhesion has been reviewed together with the application progress and bottleneck issues about anti-icing in view of the process of icing.Subsequently,the reliability and development prospect of active,passive and active-passive integrated anti-icing technology are discussed,respectively.
基金supported by the National Natural Science Foundation of China (No. 11772233)。
文摘Literature has demonstrated that Carbon Nanotubes(CNTs) can greatly enhance the electrical conductivity and matrix-dominated mechanical properties of fibrous composites. However, electrothermal coupling effect of CNTs on Carbon Fiber Reinforced Plastics(CFRPs) has scarcely been considered. This work prepared and introduced thin and porous CNT webs to the surface or/and interface of a CFRP to enhance its electrothermal properties. The results show that CNT webs can enhance the transverse electrical conductivities of the CFRP by 231%-519% in a current range of 50–150mA, when compared to the base-CFRP. Also, the surface temperature of CNT webs decorated CFRP can be improved by 20.5–32.3℃ within 3min showing a self-heating rate of 6.8–10.8℃/min just with an applied voltage of 20–30V, increased by 152%-177% when compared to the base-CFRP(2.7–3.9℃/min). Also, deicing can be finished within 4–10min with a voltage of 18V and an input power of 246W/m^(2). Moreover, the electrothermal processes nearly have no negative effect on the mechanical properties of the CFRP. The relatively low input power and short response time for deicing make the CNT webs decorated CFRP may be a potential new generation for aeronautical deicing structure.
基金financially supported by the National Natural Science Foundation of China (21875261, 51925307 and 21733010)the National Key Research and Development Program of China (2020YFE0100300 and 2018YFA0208502)+1 种基金the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (ZDBS-LYSLH031)the Youth Innovation Promotion Association of the Chinese Academy of Sciences (2018044)。
文摘Solar anti-icing/de-icing is an environmentally friendly way to convert light energy into heat with the purpose of melting/removing ice. However, the inherent intermittency of solar irradiation limits the application of solar-thermal energy-conversion technologies, when continuous de-icing is required. Herein, we investigate a solar phase-change material(SPCM) that consists of expanded graphite(EG)/paraffin/polydimethylsiloxane(PDMS), which can not only perform the solar-thermal conversion but also release/store thermal energy. Under sunlight, the SPCM effectively collects and converts the light energy into thermal energy for later antiicing/de-icing. To prepare for a no-light period, e.g., in the evening, the converted thermal energy can be stored in the SPCM using a phase transition. In this way, the energy can be released when needed to keep the temperature of a surface from freezing. The SPCM surface shows excellent anti-icing/de-icing properties such as a long droplet freeze-delay time(td> 2 h), even at an ultra-low temperature(-40℃), using only the light of one sun. This freeze-delay time is much longer than that for a surface without PCM. The tested SPCM surfaces show a high de-icing rate(2.21 kg m^(-2)h^(-1)) under real-life conditions. In addition, the SPCM shows a high de-icing rate and excellent durability. This study provides a promising route for the utilization of solar energy in anti-icing/de-icing applications.