Deicing Research Articles

FDTS‐Modified SiO2/rGO Wrinkled Films with a Micro‐Nanoscale Hierarchical Structure and Anti‐Icing/Deicing Properties under Condensation Condition

AbstractIcing accretion on the surface of an aircraft not only increases the weight but also causes changes in the surface shape, so there is an urgent need for anti‐icing/deicing without shutdown. Here, a graphene‐based film with light weight, super‐hydrophobicity, high electric heat, and durability, which has both anti‐icing properties and electrothermal deicing capability, is proposed. The film is prepared with 1H,1H,2H,2H‐perfluorodecyltrichlorosilane (FDTS)‐modified SiO2/rGO wrinkles, and it has a micro‐nanoscale hierarchical structure. Moreover, the superhydrophobic properties of the film can be controlled by adjusting the wrinkle size. Because of its good water repellency, the film can prevent and delay the freezing of water droplets at low temperatures. At −10 °C, compared to a smooth rGO film, the icing time of 10 µL supercooled water droplet on the micro‐nanoscale hierarchical structured film can be delayed by ≈8.3 times, and the ice adhension decreases greatly. In addition, the film exhibits high‐efficiency electrothermal properties. At −10 °C, under a low voltage of 15 V, the film can be heated rapidly to achieve rapid deicing and defrosting. The graphene‐based micro‐nanoscale hierarchical structure shows great potential in the field of sky anti‐icing and real‐time deicing.

Numerical simulation and validation of electro-impulse de-icing on a leading edge structure

The Electro Impulse De-Icing (EIDI) system offers an energy-efficient way of mechanically de-icing aircraft. Structural deformations induced by electromagnetic fields remove the accreted ice, and during this failure process different phenomena can be observed. A complex pattern of multiple cracks arises inside the ice layer, whereas in the ice-structure interface delaminations occur. This paper presents a numerical approach to model the combined failure process and compares it to experimental results. Cohesive zones are chosen to describe the complex fracture processes inside the ice layer while an interfacial shear stress criterion is used to determine the ice detachment from the structure. The numerical model is applied to a leading edge structure and the simulations are validated by comparison with experimental studies performed under realistic icing conditions in an icing wind tunnel. The results of several consecutive de-icing impulses show that the dynamic structural behavior and de-icing process can be approximated very well by the simulations. Furthermore, different approaches to model the complex accreted ice shape are proposed and the results are compared to each other.

Advanced de-icing system of regional aircraft

A methodology has been developed for calculating of aircraft pneumatic de-icing system parameters. It includes determination of protection zones, calculation of boot pressurizing system and calculation of boot depression system. The de-icing system parameters were calculated using as example the An-140 regional aircraft. The comparative analysis of parameters of traditional air-thermal anti-icing system and pneumatic de-icing system showed the effectiveness of the latter for regional aircraft. The developed methodology can be used in design of aircraft de-icing system.

Analysis of Methods to De-Ice Roads

Analysis of Methods to De-Ice Roads

Developing anti-icing airfield runways using surface embedded heat wires and renewable energy

Airfield runway safety is significantly affected by winter snow, ice, and slush conditions. These wet wintry conditions impact aircraft control and stopping distances. Airport operators use deicing chemicals and plowing to maintain safe runways during wet wintry conditions. However, snow removal is costly. This article presents an alternative approach to applying deicing chemicals and plowing. The approach discusses using a heated pavement system (HPS) with surface embedded wire. Nichrome heating wire is embedded at the slab surface level and energized by an outside source to heat the pavement through Joule heating. Renewable energy generated through a photovoltaic system is used to energize the wires within the concrete slab. To reduce energy demand, the system is designed as an anti-icing system in contrast to a deicing system. Consequently, energy is continually supplied to the system to maintain an above freezing pavement surface temperature independent of ambient weather conditions.An anti-icing runway slab was developed by supplying DC energy from a photovoltaic energy system to experimental concrete slabs with surface embedded heat wire. Experiments were conducted supplying energy to test panels and analyzing pavement surface temperature changes. Energy usage is controlled in the proposed system using control relays. The control relays allow current flow to only surface embedded wires in pavement sections that require a pavement surface temperature increase. This article identifies the challenges and benefits of using surface embedded heat wires with a photovoltaic system to develop an anti-icing pavement system. The approach discussed in this article proposes methodology to develop an anti-icing airfield runway pavement system that relies on a sustainable energy source, solar energy, as it’s energy source. Solar energy is used to recharge a storage energy bank for energizing the proposed system.

Unsteady simulation of aircraft electro-thermal deicing process with temperature-based method

Considering the mass and energy sources carried by the accumulated ice layer, an unsteady heat and mass transfer model of the runback water film on the deicing surface is established to simulate aircraft electro-thermal deicing process. With the extension of the freezing coefficient to the transient calculation, the coupled heat transfer of the runback water and the solid skin is solved at each time step by a temperature-based method. Unsteady numerical simulation is carried out for the electro-thermal deicing system of a NACA 0012 airfoil. The temperature variations with time are in acceptable agreement with the literature data, and the unsteady temperature-based deicing model is verified. The calculation results of temperature, runback water flux and ice thickness on the deicing surface are analyzed at different time points, and it is shown that the unsteady electro-thermal deicing model can capture the main features of the icing, ice melting and re-freezing processes in the transient deicing simulations.

3D printed electro-thermal anti- or de-icing system for composite panels

3D printing techniques have been recently used for not only prototyping applications but also producing functional systems due to its ability to fabricate complex, accurate and low manufacturing cost parts. Yet, it has not been used for manufacturing anti-icing/de-icing composites systems due to the lake of continuous conductive fillers that can be used as a heating element. The current study describes the design and manufacturing process of 3D printed composite heaters configurations using fused deposition modelling (FDM). By combining continuous network of metal wires with a polymer matrix through a modified open source printer, continuous wire polymer composite (CWPC) heaters was created. The continuous wire within the composite works as a heating element. The approach was used to manufacture 3D printed panel heaters which were implemented in anti-icing/de-icing system. The panels showed stable operation and uniform temperature distribution. The panels were sprayed with commercial hydrophobic coating to enhance anti-icing performance. Furthermore, the system was tested in field on a navy ship sailing in the arctic circle where the objective was investigating the system performance in a real-life condition. Results showed that the system was sufficient in keeping the fabricated samples ice free while the coating reduced the amount of consumed energy by around 50% depending on the operation mode. The findings showed that the combination between the active electrothermal system and the passive hydrophobic coating was the most sufficient method to keep the system ice free under the test sea conditions.

Influence of Geometrical Parameters on Heat Transfer of Transversely Corrugated Helically Coiled Tube for Deicing Fluid

In order to ensure flight safety in cold winter, aircraft ground deicing is crucial and necessary. In Chinese deicing fluid heating system, the helically coiled tube is paramount exchanger to heat deicing fluid. The deicing fluid is ethylene-glycol-based mixture with high viscosity. Aiming at heat transfer enhancement of deicing fluid, ring rib is formed by an embossed tube wall toward the internal of the tube; thus, transversely corrugated helically coiled tube (TCHC) is achieved. Depth and width are two key geometrical parameters of ring rib. Based on field synergy principle, the influence of depth–diameter ratio (H/D) and width-diameter ratio (w/D) is investigated through numerical simulation. The results show that outlet temperature, mean convection heat transfer coefficient, and Nusselt number have similar trends, which first increase and then decrease nonlinearly. The variation of flow resistance coefficient is inversely proportional to Reynolds number. Especially, the effect of H/D is more significant than that of w/D. Field synergy angle and velocity field are also analyzed to reveal the mechanism of heat transfer. TCHC performs better than the original tube. Orthogonal experiment calculates the outlet temperature of TCHC when H/D and w/D change. The combination of H/D=0.075 and w/D=0.5 is best solution. TCHC effectively enhances heat transfer of deicing fluid. Therefore, TCHC is beneficial to improve the deicing efficiency and ensure the flight punctuality.

Studies on the Electro-Impulse De-Icing System of Aircraft

In order to solve the accidents caused by aircraft icing, electro-impulse de-icing technology was studied through numerical simulation and experimental verification. In addition, this paper analyzed in detail the influence of the number, placement arrangement, and starting time of pulse coils on the de-icing effect, which plays a guidance role in the design and installation of the subsequent electro-impulse de-icing system. In an artificial climate chamber, the new de-icing criteria were obtained by tensile test, and the platform for the electro-impulse de-icing system was built. Replacing the skin with an aluminum plate, an electro-impulse de-icing system with a single coil was used. A three-dimensional skin-ice layer model was established by using Solidworks software. The finite element method was adapted. Through comparison between the de-icing prediction results and the test results in the natural environment, it was proven that the calculation process of de-icing prediction was correct, which laid a theoretical foundation for the selection of the number, placement arrangement, and starting time of the pulse coils. Finally, in this paper, by choosing the leading edge of NACA0012 wing as the research object, the influence of the number, placement arrangement, and starting time of pulse coils on the de-icing effect was analyzed. The results show that to get a better de-icing effect, the electro-impulse de-icing system with two impulse coils should be selected. The two coils were installed in the central position of the top and bottom surfaces of the leading edge, respectively. In addition, one of the impulse coils started working 1200 μs later than the other one.

Creep behaviour of FM906 glass-fibre epoxy as used in heated fibre metal laminates

An innovative deicing system for aircraft leading edges has been developed which integrates heater elements into fibre metal laminates. Such an electrical system can lead to weight reductions and more efficient performances compared to conventional bleed air systems. However, the combination of thermal and mechanical loadings also raises new questions on the durability of such a structure, in particular due to the repeated heating to elevated temperature. The linear viscoelastic creep behaviour, including the effects of temperature and ageing, is therefore investigated for manufactured FM906 glass-fibre epoxy composite as used in heated GLARE. A master curve is derived based on the time–temperature and time–age superposition. The effect of physical ageing during loading is included in a long-term creep prediction.

The Preparation and Anti-Icing Properties of Flexible Surfaces

The Preparation and Anti-Icing Properties of Flexible Surfaces

Investigation on wavy characteristics of shear-driven water film using the planar laser induced fluorescence method

Aircraft icing poses a serious threat to flight safety. Unfrozen impinging water on the surface of the aircraft will run back under the effect of high-speed airflow, altering liquid distribution and heat transfer characteristics. In this paper, a series of experiments were conducted over a wide range of air speed (Ua = 20.8–56.6 m/s), film Reynolds number (Ref = 26–128) to investigate the dynamics of ultrathin water film on an Aluminum substrate. The analyses of water film thickness and wavy characteristics were conducted through the planar laser-induced fluorescence method, in which the variations of transient characteristics of water film thickness with both the air speed and flow rate were analyzed. The statistics of water film thickness characteristics indicates that, the ratio of surface roughness of water film to its mean thickness is 0.4–0.8. The variation of the wave parameters of gas-liquid interface with both the air speed and the Reynolds number of the water film are also presented and analyzed in detail, including the main frequency of wave, interface wave height, surface wave velocity, interface wave curvature, and wave length parameters. This work is helpful to fundamentally understanding the wavy characteristics of shear-driven water film, as well as optimize the de-icing system for aircraft.

Intersection-pavement de-icing: comprehensive review and the state of the practice

Intersection-pavement de-icing: comprehensive review and the state of the practice

Life-Cycle cost-benefit analysis of Bridge deck de-icing using geothermal heat pump system: A case study of North Texas

Transportation infrastructures suffer major damage from ice and snow each year, negatively affecting the U.S. economy. Bridges, a key element of the transportation network, are the most vulnerable to impairment from ice and snow. The conventional snow and ice removal system (CSRS) is not a satisfactory solution, as it causes additional problems relating to the acceleration of bridge deck corrosion, motorist safety, travel delays, and environmental damages. In an attempt to provide a sustainable, economically viable alternative, this research performed a scenario-based life-cycle cost-benefit analysis (LCCBA) of the geothermal heat pump de-icing system (GHDS). The results of the analysis show that the benefits of the GHDS outweigh its cost. In addition, the output of a sensitivity analysis, using the Monte Carlo Simulation (MCS), indicates that traffic flow enhancement is the most dominant variable affecting the overall result. For a daily traffic volume of 24,000 vehicles, the benefits are estimated to be 2.32 times greater than the costs, with 95% reliability. The analysis output demonstrates that the application of the GHDS is economically viable for bridges with a minimum daily traffic volume of 7000 vehicles.

Alternative hydronic pavement heating system using deep direct use of geothermal hot water

Researchers have studied and well documented several alternative snow-melting and de-icing systems. In addition to the snow-melting efficiency of such systems, they are considered to be more environmentally friendly than traditional mechanical or chemical de-icing procedures and more economical than some other alternative snow-melting methods. The most important factor for a hydronic heating system is the heat source. In western North Dakota, six aquifers have been identified in the Williston Basin that can provide geothermal hot water for direct use. Ancillary to these aquifers, co-production wells used in the oil industry may also provide hot water for use in a hydronic heating system. Given the availability of these aquifers and co-production wells, the focus of this study is the numerical analysis (using a finite element method) of a piped hydronic pavement heating system. The analysis results are examined in terms of available scenarios for the direct use of geothermal hot water that consider water temperature, volumetric flow rate, and the heat requirements for weather conditions in western North Dakota. This paper presents and discusses the results in terms of the temperatures of the heated pavement and the outlet temperatures of water after it has circulated through embedded pipes.

An accurate detection method for turbine icing issues using LSTM network

As one of the most widely applied clean energy resources, wind power generation is helpful for energy structure adjustment and sustainable development, whereas blade-icing failure affects the stability and benefits of wind farm. In consideration of efficiency improvement and safety hazard control, this paper proposed a failure detection model based on long short-term memory network. With the combination of turbine operation mechanism and data-driven method, the early warning of blade icing was implemented, which made it possible to take timely measures such as turning on the de-icing system at early moments of icing issues. The operational data collected by SCADA system were used as input for model, and progressive trend as well as hidden messages were learned from historical correlation at both temporal and characteristic scales. Consequently, the model achieved the fault detection and performed well on test dataset.

融雪剂对Cd在土壤中吸附规律及动力学影响

融雪剂对Cd在土壤中吸附规律及动力学影响

Compare study between icephobicity and superhydrophobicity

Although surface microstructures is the key to superhydrophobicity, and possibly leads to significant icephobicity when a water droplet freezes on superhydrophobic surfaces (SHS), thermodynamic mechanisms responsible for the icephobicity and anti–icing still need to be further studied. For this reason, we established the relationships between some quantities, i.e., contact angle (CA) together hysteresis (CAH), adhesion work and the microstructures by a three–dimension (3–D) surface model, and theoretically explained the anti–icing and icephobicity from the SHS. Our theoretical and experimental study indicate, the adhesion work (Wai) of a frozen water droplet to the SHS in composite wetting state (CWS) is apparently less than that in the non–composite wetting state (NCWS). Therefore it is necessary to create such CWS by designing surface micro/nanostructure. Further study also shows, the adhesion work (Waw) of a water droplet to the SHS is larger than that (Wai) of their frozen, thus implying decrease of the adhesion work after icing. This will improve on the understanding of the SHS for anti–icing and icephobicity.

The design and simulation of an automated de-icing control system in the aircraft diamond DA42

The design and simulation of an automated de-icing control system in the aircraft diamond DA42

A Modeling Approach of Heat Transfer of Bridges Considering Vehicle-Induced Thermal Effects

AbstractThe design and application of bridge deicing systems require an understanding of heat-transfer mechanisms of the bridge. One of these systems is geothermal foundations that support structural loads and utilize heat exchange with the surrounding soil. To design such a bridge deicing system and ensure ice-free surfaces during winter, accurate prediction of the temperature of bridge decks is vital. Heat-transfer mechanisms of the bridge deck include many factors such as convection between air and deck, solar radiation, and longwave radiation. Despite considerable research in this area, traffic vehicle effects on the heat balance of the bridge have not been fully investigated. In this paper, a two-dimensional finite-element analysis that focuses on natural factors is proposed and validated using measured data. After the validation, the model was extended to include the vehicle effects for conditions of both light and heavy traffic, considering tire frictional heat and vehicle-induced convection and radiation. The results show that the vehicular traffic increased the bridge surface temperature by up to 2°C with light traffic and by up to 4°C with heavy traffic, thus providing an advantage for deicing. Traffic effects can cool the bridge surface temperature down by up to 2°C, mainly during the summertime. Therefore, the traffic effects can be optionally considered during the design of bridge deicing systems.