De-icing Process Research Articles

Evaluating the effectiveness of innovative pervious concrete pavement system for mitigating urban heat island effects, de-icing, and de-clogging

The Urban Heat Island (UHI) effect and water runoff pose significant challenges in urban environments. This research aimed to mitigate the UHI effect through the implementation of an innovative pervious concrete pavement (IPCP) system. Furthermore, the study investigated the main obstacles associated with conventional permeable pavements, such as clogging and vulnerability to freeze-thaw damage. To achieve this goal, a physical model apparatus was developed to simulate temperature variations, de-icing processes, and clogging incidents in the IPCP system. This apparatus was specifically designed with distinct sections for both the pervious concrete layer and the subbase layer. The findings revealed that careful selection of an appropriate subbase material significantly contributed to reducing the temperature rise (up to 37 %) under varying environmental conditions by enhancing evaporative cooling capacity. Additionally, the pavement simulation apparatus featured a dual-function drainage system. This system not only regulated the water level within the pavement by draining excess water but also addressed clogging (with up to 97 % permeability recovery) and de-icing concerns through the application of air pressure and hot water injection, respectively.

Simulation-Guided Preparation of Copper Chalcogenide Nanoparticle-Based Transparent Photothermal Coating with Enhanced Deicing Performance.

In this investigation, transparent photothermal coatings utilizing plasmonic copper chalcogenide (Cu2-xS) nanoparticles were designed and fabricated for the deicing of glass surfaces. Cu2-xS nanoparticles, chosen for their high near-infrared (NIR) absorption and efficient photothermal conversion, were analyzed via finite difference time domain (FDTD) simulations to optimize nanoparticle morphology, thus avoiding costly trial-and-error synthesis. FDTD simulations determined that Cu2-xS nanorods (Cu-NRs) with an optimal aspect ratio of 2.2 had superior NIR absorption. Guided by FDTD simulations, the composite coating composed of Cu-NRs in clear acrylic resin paint was brush-coated to glass, achieving 62.4% visual transmittance and over 95% NIR absorbance. Photothermal conversion tests exhibited a significant temperature increase, with the coating reaching 65 °C under NIR irradiation within 6 min. The dynamic deicing process of ice beads on the coating at -20 °C completed within 220s, in contrast to the frozen state on glass coated with clear acrylic resin paint. Furthermore, heat transfer simulations in COMSOL illustrated melting initiation at the ice-coating interface and subsequent progression through the ice layer. This simulation-driven synthesis method and photothermal testing offer a design framework for the fabrication of photothermal deicing coatings with applications for automobiles, buildings, and aircraft in cold environments.

Analysis and Research on Energy Consumption of a Non-Contact High-Efficiency Tunnel De-Icing Device

In this paper, a laser deicing device for tunnel is designed to solve the inconvenience of deicing the tunnel roof wall. First of all, Solidworks software was used to create a 3D model of the laser deicing device, namely the track module, the base platform, and the work platform. Then, ANSYS simulation software is used to simulate the process of laser deicing. When the initial temperature of icicle is -5℃, -10℃, -15℃ and -20℃, the distance between laser and icicle is 1.5m, 2m, 2.5m and 3m, and the wind speed is 2m/s, 3m/s, 4m/s and 5m/s, respectively. The depth of 200s of laser irradiation and the time of full penetration were simulated under three variables. It is concluded that the higher the initial temperature, the closer the distance and the smaller the wind speed, the lower the deicing energy consumption. Finally, the experiment results are consistent with the simulation results, which further verifies the accuracy of the simulation. The laser deicing detection device studied in this paper provides a certain theoretical basis and reference value for the application and development of intelligent deicing equipment in tunnels.

De-icing behavior and efficiency of electrothermal film surfaces with different non-wettability in low-temperature flow field

The electrothermal anti-/de-icing technology with excellent de-icing efficiency has been widely applied to eliminate the icing threat on airfoil, whose essence is heat transfer process between heating surface and ice. However, the heat transfer behavior and interfacial transformation form of ice accretion are indistinct on traditional non-superhydrophobic surfaces and rapidly-developed superhydrophobic surfaces in the low-temperature flow field. Therefore, the heat transfer and solid-ice interface transform behavior on film heater surface were explored in this work by analyzing the temperature-rising performance and de-icing characteristics of hydrophobic films (HPoF) and superhydrophobic films (SHPoF) in the icing wind tunnel. The results indicated that the faster wind speed enhanced the convection and radiant heat loss of the film heater, and the peak temperature of film heater was directly affected by the environment temperature. Moreover, the SHPoF had lower de-icing consumption than HPoF in an environment without wind field, which was less related to the ice accretion. However, the de-icing form transformed from shearing to shedding mode with the growth of ice accretion under wind field conditions. In the shearing de-icing mode, the lower environment temperature and faster wind speed caused longer de-icing time, whereas the deicing time shortened with the decrease of environment temperature in the shedding mode. When the icing time was 1 min, the de-icing time of SHPoF increased by 12.25%–25.73 % due to the slower heat transfer at the solid-gas-ice interface compared to the solid-liquid-ice interface of HPoF. With the further increase of icing time, the ice accretion was removed after the melt of interfacial ice. The less solid-ice contact points were present at the solid-gas-ice interface on SHPoF surfaces, resulting in energy saving of 20.16%–40.46 % compared to HPoF surfaces. Therefore, the electrothermal superhydrophobic de-icing technology exhibited energy-efficient characteristics when the self-weight of ice is the primary driving force for de-icing process.

A Bayesian Deep Learning-based Wind Power Prediction Model Considering the Whole Process of Blade Icing and De-icing

A Bayesian Deep Learning-based Wind Power Prediction Model Considering the Whole Process of Blade Icing and De-icing

Comparative Experimental Study on the De-Icing Performance of Multiple Actuators

The issue of aircraft icing poses a substantial threat to flight safety. In order to investigate more efficient anti-icing and de-icing technologies, a comparative analysis was conducted on the de-icing characteristics of three types of actuator materials under varying conditions. Initially, experimental research was undertaken to analyze the temperature traits of three actuators under ice-free conditions. Three power densities were chosen for the experiment: 0.170 W/cm2, 0.727 W/cm2, and 1.427 W/cm2. The research findings revealed distinct characteristics: plasma actuators and resistance wire actuators exhibited a strip-like high-temperature region during operation, with well-defined boundaries between the high-temperature and low-temperature zones, whereas ceramic-based semiconductor actuators showcased a uniform high-temperature region. As energy consumption rose, the thermal equilibrium temperatures of all three types tended to converge, with resistance wire actuators operating at 1.427 W/cm2, showing the highest temperature rise rate at that power density. Subsequently, experimental research was carried out on the de-icing performance of three actuators under icing conditions at a specific power density. Following 120 s of de-icing, the ice layer covering the surface of the plasma actuator completely melted, forming a cavity. Conversely, the ice layer on the ceramic-based semiconductor actuator remained partially intact in a strip shape. Ice deposits were still visible on the surface of the resistance wire actuator. This observation highlights the remarkable de-icing speed of the plasma actuator. The propulsive force of plasma generated on the fluid inside the ice layer enhances heat transfer efficiency, thereby accelerating the de-icing process of the plasma actuator at the same power density. The analysis of the de-icing performance of these three novel types of actuators establishes a robust groundwork for exploring more effective aircraft de-icing methods. Furthermore, it furnishes theoretical underpinning for the advancement of composite anti-icing and de-icing strategies.

Numerical Analysis of the Wing Leading Edge Electro-Impulse De-Icing Process Based on Cohesive Zone Model

Aircraft icing has historically been a critical cause of airplane crashes. The electro-impulse de-icing system has a wide range of applications in aircraft de-icing due to its lightweight design, low energy consumption, high efficiency, and other advantages. However, there has been little study into accurate wing electric-impulse de-icing simulation methods and the parameters impacting de-icing efficacy. Based on the damage mechanics principle and considering the influence mechanisms of interface debonding and ice fracture on ice shedding, this paper establishes a more accurate numerical model of wing electric-impulse de-icing using the Cohesive Zone Model (CZM). It simulates the process of electric-impulse de-icing at the leading edge of the NACA 0012 wing. The numerical results are compared to the experimental results, revealing that the constructed wing electro-impulse de-icing numerical model is superior. Lastly, the effects of varying ice–skin interface shear adhesion strengths, doubler loading positions, and impulse sequences on de-icing effectiveness were studied. The de-icing rate is a quantitative description of the electro-impulse’s de-icing action, defined in the numerical model as the ratio of cohesive element deletions to the total elements at the ice–skin interface. The findings reveal that varying shear adhesion strengths at the ice–skin interface significantly impact the de-icing effect. The de-icing rate steadily falls with increasing shear adhesion strength, from 66% to 56%. When two, four, and seven impulses were applied to doubler two, the de-icing rates were 59%, 71%, and 71%, respectively, significantly increasing the de-icing efficiency compared to when impulses were applied to doubler one. Doubler one and two impulse responses are overlaid differently depending on the impulse sequences, resulting in varying de-icing rates. When the impulse sequence is 20 ms, the superposition results are optimal, and the de-icing rate reaches 100%. These studies can guide the development and implementation of a wing electric-impulse de-icing system.

Quantitative monitoring of icing on CFRP laminate with guided wave combining forward modeling and inverse characterization

Aircraft icing is one of the critical factors for flight safety. Timely and accurate monitoring of in-flight ice accretion is essential for flight systems to take immediate and effective action to significantly improve the efficiency of subsequent de-icing processes and ensure flight safety. Since carbon fiber reinforced polymer (CFRP) are now widely used in the aviation industry, the study of ice accretion on the surfaces of CFRP with anisotropic properties is of great importance. In this work, a three-dimensional frequency domain finite element model for icing CFRP laminate is first established, via which the mechanism of mode conversion of ultrasonic guided waves (UGWs) at different ice layer thicknesses is quantitatively analyzed. Then, the time-domain finite element simulation was performed, from which the time–frequency domain spectrogram of the acquired UGW signal is obtained by short-time Fourier transform (STFT). The extracted frequency–time-of-flight (ToF) curve of the signal via STFT shows high agreement with the theoretical results, which confirms the influence of icing on UGW propagation. Finally, numerous experiments with bonded lead zirconate titanate wafers to excite and acquire UGWs are conducted with different ice layer thicknesses and lengths on CFRP. The extracted frequency–ToF curves of UGW signals are used as input to a two-layer feedforward artificial neural network (ANN) to accurately evaluate the length and thickness of the ice layer. The high reliability of this method with ANN is confirmed, which shows the potential of the proposed UGW-based method for quantitative monitoring of icing length and thickness on aircraft CFRP laminate.

An Experimental Study on Blade Surface De-Icing Characteristics for Wind Turbines in Rime Ice Condition by Electro-Thermal Heating

Wind turbines in cold and humid regions face significant icing challenges. Heating is considered an efficient strategy to prevent ice accretion over the turbine’s blade surface. An ice protection system is required to minimize freezing of the runback water at the back of the blade and the melting state of the ice on the blade; the law of re-freezing of the runback water is necessary for the design of wind turbine de-icing systems. In this paper, a wind tunnel test was conducted to investigate the de-icing process of a static heated blade under various rime icing conditions. Ice shapes of different thicknesses were obtained by spraying water at 5 m/s, 10 m/s, and 15 m/s. The spray system was turned off and different heating fluxes were applied to heat the blade. The de-icing state and total energy consumption were explored. When de-icing occurred in a short freezing time, the ice layer became thin, and runback water flowed out (pattern I). With an increase in freezing time at a low wind speed, the melting ice induced by the dominant action of inertial force moved backward due to the reduction in adhesion between the ice and blade surface (pattern II). As wind speed increased, it exhibited various de-icing states, including refreezing at the trailing edge (pattern III) and ice shedding (pattern IV). The total energy consumption of ice melting decreased as the heat flux increased and the ice melting time shortened. At 5 m/s, when the heat flux was q = 14 kW/m2, the energy consumption at EA at tδ = 1 min, 5 min, and 7 min were 0.33 kJ, 0.55 kJ, and 0.61 kJ, respectively. At 10 m/s, when the heat flux was q = 14 kW/m2, the energy consumption at EA at tδ = 1 min, 3 min, and 5 min were 0.77 kJ, 0.81 kJ, and 0.80 kJ, respectively. Excessive heat flow density increased the risk of the return water freezing; thus, the reference de-icing heat fluxes of 5 m/s and 10 m/s were 10 kW/m2 and 12 kW/m2, respectively. This paper provides an effective reference for wind turbine de-icing.

A de-icing experimental investigation of blade airfoil for wind turbines based on external hot air method

Wind turbines operating in cold and wet climates are prone to icing on the surface of their blades. It is necessary to develop effective de-icing methods for wind turbine blades. The commonly used blade de-icing method is heating, which includes the blade internal hot air method and the surface heating method. Recently, the use of external heat sources for blade de-icing has also received attention, such as the use of steam, infrared, and hot air, etc. In this research, the external hot air de-icing method for wind turbine blade was studied by experiments. A de-icing experimental system based on external hot air method was designed and established. The de-icing test was carried out on a blade segment with NACA0018 airfoil. The initial ice shape of blade airfoil was obtained by using an icing wind tunnel. The de-icing experiments were set up with four hot air temperatures and four hot air velocities. The deicing process was recorded by a high-speed camera, and the temperature changes on the blade surface are measured by an infrared thermal instrument. Furthermore, the de-icing time, de-icing area, de-icing rate and de-icing energy efficiency under different conditions were calculated and analyzed. According to the results, the external hot air method can effectively perform blade de-icing. The temperature and speed of the hot air have a significant impact on the de-icing process. Under the condition of this test, the maximum de-icing energy efficiency reached as 6.33 % at hot air temperature of 35 °C and velocity of 9 m/s. This study can provide a reference for solving the wind turbine blade icing problem by using external hot air de-icing method.

Effect of hydrophobization of airfield coatings on the consumption of deicing reagents2

The issue of reducing costs for the maintenance of airfield coatings is particularly important nowadays due to the increase in the intensity of domestic air transportation. A significant part of the costs of the operational maintenance of airfields is spent on the purchase of deicing reagents (DIR) used to protect airfield pavements from icing. There is a possibility to reduce the required amount DIR by using of hydrophobizing impregnations (HPI) for cement concrete airfield pavements. The assumption about possibility to reduce costs for DIR by using HPI was proven by laboratory tests on specimens of cement concrete slabs. In the course of laboratory tests the process of airfield pavement icing and de-icing was modeled. According to the results of experimental studies it was determined that the consumption of DIR for cement concrete slabs specimens treated with HPI was reduced by 35% compared to similar specimens without HPI treatment. For the economic evaluation of cost reduction for the purchase of DIRs, the costs of applied DIRs used at civil airfields of the Russian Federation were analyzed, taking into account their location in different climatic zones. The assessment has revealed that the cost savings for the purchase of DIRs can be up to 29.1 %.

Study on de-icing criterion of anti-icing coating and simulation analysis method of mechanical de-icing process for polar ship superstructure

The considerable amount of ice accumulation on the surface of polar ship superstructure has seriously threatened the navigation safety of the Polar ships. Anti-icing coating has become one of the most effective anti-icing methods for polar ships. When the coating surface is covered with ice for a long time, mechanical de-icing measures should be taken for the icing on the coating surface. In this study, the static icing adhesion shear strength and normal peeling strength of the anti-icing coating were examined, introduction of temperature parameters into existing de-icing criterion, so as to simulate the energy required for mechanical de-icing and the efficiency of de-icing without damaging the anti-icing coating. The simulation analysis of mechanical de-icing and coating peeling of typical hull structures (e.g., flat plate structure, curved parapet structure, curved structure with 70 mm radius and 120 mm radius) was completed in accordance with the criterion. Moreover, the range of energy required for mechanical de-icing and the de-icing efficiency of the above-mentioned typical structures were derived. The de-icing criterion and peeling strength criterion of anti-icing coating and the numerical simulation method proposed in this study can lay a solid technical basis for the design and performance evaluation of polar ship anti-icing systems in the future.

Integrated composite electrothermal de-icing system based on ultra-thin flexible heating film

Icing is a serious threat to the flight safety of aircraft. Lightweight and efficient electrothermal de-icing systems for carbon fiber reinforced polymer components are expected to contribute to the lightweighting and electrification of aircraft. This study presents the development and test of a novel, integrated, multifunctional composite electrothermal ice protection system. The system achieves this by incorporating a carbon-based ultra-thin flexible heating film into a carbon fiber-reinforced polymer composite laminate. T700 and M40 carbon fiber prepregs were used. The system composition and configuration were designed based on the anisotropic mechanical and thermal properties of the carbon fiber-reinforced polymer composite. The effects of ply stacking sequence, presence of insulation layer, ply angle, heating area, and prepreg type on thermal response and de-icing performance were investigated. Thermal response experiments were carried out in both room temperature and low temperature environments. A one-dimensional thermal response analysis model was developed for a representative heating structure. Comparative de-icing experiments were conducted on different samples in a low-temperature test chamber. A numerical model, based on the modified enthalpy-porosity method, was developed to simulate the de-icing process, and showed good agreement with the experimental results. Experiments and numerical calculations show that the arrangement of the heater close to the deicing surface improves the performance of the electrothermal deicing system while maintaining the overall mechanical properties of the multi-layer structure. While the insulation layer helps marginally with heat loss during de-icing, it significantly increases the system’s thermal inertia, which delays the de-icing’s start. It is recommended to minimize or eliminate insulation layer thickness. Rapid de-icing effects, combined with energy conservation, can be achieved through a short-term, high-power heating strategy.

Dynamic simulation of aircraft electro-impulse de-icing using bond-based peridynamics

Electro-impulse de-icing is a lightweight type of mechanical de-icing system that consumes little energy, provides high reliability, and offers wide application prospects. In this study, the bond-based peridynamics theory was used to simulate the dynamic damage process and evolution law of aircraft electro-impulse de-icing. The ice layer was simplified as a brittle material that satisfies the linear elastic constitutive relation. A numerical analysis model of the ice layer, aircraft skin substrate, and their interface was established to simulate the dynamic responses under a high strain rate. Considering the anisotropy of ice adhesion on the substrate, the interfacial bonds were described as shear bonds and tensile bonds, and the critical elongations of the two were derived. The tensile and shear capacities of the ice on the substrate were then simulated using these critical elongations, and the peeling rates of single ice particles and interfacial ice layers were taken as indexes describing the efficacy of electro-impulse de-icing. The process of electro-impulse de-icing was then analyzed for an aluminum substrate with two adjacent clamped edges. Finally, the results of the peridynamic simulation were compared with those of existing experiments and finite element models to verify the effectiveness of the peridynamic approach.

Computational simulation of aircraft electrothermal de-icing using an unsteady formulation of phase change and runback water in a unified framework

Accurately predicting de-icing processes is essential to ensure the proper sizing and design of ice protection systems in aircraft icing. A unified framework was developed to simulate an unsteady electrothermal de-icing process, using an unsteady formulation to account for phase change and runback water. Two physically-motivated concepts were newly introduced to the icing model to accurately describe the unsteady electrothermal de-icing (ice accretion/melting) process. A conjugate heat transfer method was utilized to tightly couple the ice and conduction solvers. Sub-iterations were incorporated at every time step to ensure the convergence of temperature and heat flux at the interface. The unsteady de-icing framework consists of a compressible Navier-Stokes-Fourier airflow solver, Eulerian droplet impingement solver, unsteady ice accretion/melting solver, and heat conduction solver, which can handle multilayer composite materials. All solvers were formulated based on partial differential equations and developed in a unified finite volume framework, enabling the use of a single grid system and eliminating unnecessary grid generation for the ice layer. The results showed better agreement with experimental data compared to other results. The unified solver was used to analyze the unsteady electrothermal de-icing process by investigating the ice accretion, ice melting, runback water film, and freezing of water film in unprotected areas. Runback water film due to ice melting may exceed the impingement limits and freeze in unprotected areas, leading to ice ridge formation.

Dynamic Mitigation Mechanisms of Rime Icing with Propagating Surface Acoustic Waves.

Ice accretion on economically valuable and strategically important surfaces poses significant challenges. Current anti-/de-icing techniques often have critical issues regarding their efficiency, convenience, long-term stability, or sustainability. As an emerging ice mitigation strategy, the thin-film surface acoustic wave (SAW) has great potentials due to its high energy efficiency and effective integration on structural surfaces. However, anti-/de-icing processes activated by SAWs involve complex interfacial evolution and phase changes, and it is crucial to understand the nature of dynamic solid–liquid–vapor phase changes and ice nucleation, growth, and melting events under SAW agitation. In this study, we systematically investigated the accretion and removal of porous rime ice from structural surfaces activated by SAWs. We found that icing and de-icing processes are strongly linked with the dynamical interfacial phase and structure changes of rime ice under SAW activation and the acousto-thermally induced localized heating that facilitate the melting of ice crystals. Subsequently, interactions of SAWs with the formed thin water layer at the ice/structure interface result in significant streaming effects that lead to further damage and melting of ice, liquid pumping, jetting, or nebulization.

Fabrication of anti-icing/de-icing superhydrophobic composite coating based on hydrangea-like ZnO@CuS

Considering the destructive effect of ice accumulation on material surfaces, substantial attention has been devoted to fabricating anti-icing superhydrophobic coatings. However, most superhydrophobic coatings cannot deice. Herein, a special nanofiller was designed and fabricated as the main component of a superhydrophobic coating for simultaneously improving its anti-icing and de-icing performance. Firstly, hydrangea-like ZnO@CuS (H–ZnO@CuS) was synthesized via a precipitation process at room temperature. Then, a superhydrophobic composite coating composed of epoxy resin (ER), H–ZnO@CuS, and polydimethylsiloxane (PDMS) was fabricated on the Al surface via a layer-by-layer spraying process. The results demonstrate that, after 100 tape peeling tests and 40 abrasion cycles, the hydrophobicity of the ER/H–ZnO@CuS/PDMS composite coating remains basically unchanged, and its water contact angle (WCA) can still reach 156.3°, thus exhibiting excellent superhydrophobicity and mechanical durability. More importantly, the composite coating displays outstanding anti-icing and de-icing performance, which can prolong the static freezing time of water droplets from 3 to 13 min at −15 °C and prevent the formation of ice when water is dripped continuously for 20 min at −10 °C. Additionally, the melting time of ice at −15 °C can be shortened from 5 to 1 min due to the photothermal behavior of H–ZnO@CuS. Therefore, this work presents a promising strategy to endow coatings with simultaneous anti-icing and de-icing performance. This approach can not only improve the current efficiency of de-icing/anti-icing processes but also reduce the energy consumption by effectively reducing or eliminating the accumulation of water on the structure surface before it freezes. • A special hydrangea-like composite nano-fillers as the main component of superhydrophobic coating was fabricated. • The composite coating exhibited superhydrophobicity with water contact angle of 163.5 ± 1.9° and slide angle of 3.1 ± 0.2°. • Photothermal micro/nano structure endows coating with good anti-icing and de-icing performances simultaneously • The de-icing process of ice bead on the superhydrophobic coating at −15 °C completed within 1 min by photothermal effect. • This method provides new ideas for the preparation of anti-icing and de-icing coatings for practical outdoors applications.

A Multi-Region CFD Model for Aircraft Ground Deicing by Dispersed Liquid Spray

The aircraft ground deicing (AGD) process is a mandatory step before taking off in a cold climate. The development of CFD (computational fluid dynamics) tools to simulate AGD could help the industry reduce its costs and limit pollution. Previous works have modelled some parts of the AGD process. Building on these previous works, this paper presents a three-dimensional (3D) CFD algorithm to simulate the process in full scale. The algorithm comprises a multi-region model where a Lagrangian method solves the spray particle equations, and an enthalpy–porosity approach with an Eulerian method simulates the ice melting. The multi-region approach is verified in this paper through a spray-tip penetration (STP) test. The STP predicted using the multi-region model had 99% agreement with the STP predicted using a Lagrangian method. Therefore, the multi-region technique correctly modeled the particle momentum between the two regions. This paper also presents a numerical calibration of the permeability coefficient for the extended enthalpy–porosity technique in the context of AGD. The numerical calibration of the permeability coefficient will enable future parametric studies of the AGD process.

Effect of Carbon Fiber Admixture and Length on Microwave Deicing Efficiency of Airport Road Surface Concrete

In order to improve the microwave deicing efficiency of airport road surface concrete, the method of incorporating carbon fiber materials of different doping amounts and lengths into concrete is proposed. The test method is optimized by using a fiber-optic temperature sensor and a self-developed open microwave deicing vehicle, and the effect of the coupling effect of different carbon fiber doping and length on the microwave deicing efficiency of concrete is studied. The results of the study show that the appropriate amount of carbon fiber blended into the concrete can significantly improve the microwave deicing efficiency, and the reasonable use of carbon fiber-modified concrete can achieve the purpose of efficient deicing of the airport road surface. By analyzing the temperature rise curve, temperature rise rate curve, deicing effect, and infrared thermography of the microwave deicing process, combined with the “heat generation-heat dissipation” theory, the microwave deicing is divided into four stages: concrete wave absorption, water layer formation, ice thinning, and ice breaking and ice melting. In the process of microwave deicing of concrete, changing the length of carbon fiber and the amount of doping will have a greater impact on the rate of temperature rise and deicing range, but the shape of deicing remains basically the same, mainly spindle-shaped. When the length of carbon fiber is short, it is not conducive to the absorption of microwave by concrete, and with the increase of fiber length and doping amount, the wave absorption performance of carbon fiber-modified concrete on the airport road surface is gradually improved; when the fiber length is 0.6 cm and the fiber doping amount is 2‰, the wave absorption performance is the best, and the deicing rate is 1.82 times of ordinary concrete, and the deicing area is 1.2 times of ordinary concrete.

Thermal characteristic and spatial morphology between electrode and phase changing ice during de-icing process of dielectric barrier discharge and critical behavior of the surface charge density

Dielectric barrier discharge (DBD) plasma recently has been demonstrated as an effective in situ heating methodology in anti-ice and de-ice applications of the aircraft. However, the thermal stability of this special heat source during the interactions between the plasma and the ice block may pose serious concerns. In this paper, it is found that when the ice blocks of different characteristic locations covered the DBD device with alternative current (AC) power, two different kinds of interaction processes can be resulted: First, the concentration of the heat flow through the local enhancement of the streamers between the electrode and the ice, long-lasting for the glaze ice ended with the partial evaporation of the melted ice block with larger separations, or short-lived intermittent for the rime ice until the boundary is beyond the reach. Second, sparks, very likely to be generated between the electrode and the ice block when the separation and electric field meet the transition conditions, resulting in the fast evaporation of the melted ice block and the severe aging or on-sight burning of the devices, even at the operation voltage safe for the AC-DBD plasma without ice blocks. It is emphasized that the coexistence or the number of the ice blocks of different separations does not alter such behavior. Supported by the calculation of the streamer-to-spark transition criterion, and affected by ice phase change, it is argued that the de-icing AC-DBD plasma is a strong nonlinear heat source, resulting from the surface charge accumulation, melting of the ice blocks, and the enhancement of ionization collision frequency due to the mixing of the evaporated water molecules. A new critical condition, the critical surface charge density was proposed for the initiation of spark, ρsc: Densities higher than ρsc will lead to the catastrophic spark, while the lower will lead to the selective concentration of the heat flow for the faster de-icing process. Due to the random distribution nature of the electrode-to-ice separations during the real-world practice of an AC-DBD heat source for de-icing, the existence of ρsc may be under further scrutiny and considered as a crucial factor for the stable operation of the plasma heat sources for de-icing.