De-icing Technology Research Articles

Cable Surface for the Reduction of Risk Associated with Bridge Cable Ice Accretions

Cable-supported bridges can suffer from ice and snow accretions that develop in specific weather conditions, predominantly in cold climate regions. As shedding pieces of ice and snow can be of considerable size and weight, they may pose a significant hazard for the traffic below. Numerous anti-icing and de-icing technologies have been tested in laboratories as well as on bridges, but none have proven able to effectively mitigate the risk. Solution durability has also often proven to be lacking. In this paper, a recently developed cable surface that can effectively reduce the risk associated with ice and snow shedding is presented. Experimental results and statistical comparisons between two different cable surfaces in ice shedding tests performed in a climatic wind tunnel are shown. The performance of a conventional, helically-filleted, HDPE stay pipe is compared to that of the innovative stay pipe with a concave-filleted surface. Based on the tests, it is shown that the concave-filleted surface significantly outperforms the contemporary cable surface in terms of the duration for which ice is retained on its surface. This reduces the size and mass of shed ice fragments through prolonged melting, thus reducing the risk associated with it.

Scaling Method of the Rotating Blade of a Wind Turbine for a Rime Ice Wind Tunnel Test

In order to research the law of rime ice accretion on different scaling blades surface, a new rime ice scaling method was proposed in this research. According to previous research, there are three kinds of ice types on blade surfaces: rime ice, glaze ice and mixed ice. Under the condition of rime ice, both the freezing fraction and the coefficient of heat transfer between super-cold water droplets and blade are 100%. The heat transfer model of rime ice is simpler than that of glaze ice and mixed ice. In this research, the scaling parameters including flow field, water droplets, temperature, pressure and rotating parameters were defined. The Weber number (We) based on water film thickness as an important parameter was applied in this study. The rotating parameters including rotating speed and radius had been added into the icing scaling method. To verify the effectiveness of the new rime ice scaling method, icing wind tunnel tests were carried out. The NACA0018 airfoil was used for the test blade. Two kinds of scale chord blades were selected, the chord of full-scale blade was 200 mm and of subscale blade was 100 mm. The test temperature was −15 °C. The ice accretion on different scale blades surface were captured by high-speed camera and the icing shapes of different scaling blades were obtained. To quantitatively analyze the similar degree of icing shapes on different scale blades, an evaluation method which included similar degree (Sim) was established based on the typical characteristic parameters proposed by previous research. The results show that the icing shapes of subscale blades are similar to that of full-scale blades. The similar degree is between 75.22% and 93.01%. The icing wind tunnel test indicates that the new rime ice scaling method is an effective method to study the rime ice of large scale rotating blades. This study can be used as a reference for research on anti-icing and de-icing technologies for large-scale HAWTs (Horizontal Axis Wind Turbines).

Effect of liquid water content on blade icing shape of horizontal axis wind turbine by numerical simulation

To research the law of the icing accretes on near the tip part of rotating blade of large-scale horizontal axis wind turbine (HAWT) influenced by liquid water content (LWC), the icing distribution on a HAWT rotor with rated power of 1.5 MW was simulated based on a Quasi-3D computation method. About 30% part length of blade from tip along span wise to blade root which are the most serious icing area was selected to research. Eight sections of this 30% part were decided and the ice distribution on each sections were simulated. Five kinds of LWC from 0.2 g/m3 to 1.4 g/m3 and two kinds of temperatures including ?6?C and ?18?C were selected. The medium volume droplet is 30 mm. Three kinds of icing time were selected to analyze the effects of icing time on ice accretion. The icing shape evaluate method was applied to quantitatively analyze the icing shape obtatined under different conditions. The results show that the icing shapes are all horn icing shape under the different LWC when the temperature is ?6?C. The icing shapes change from horn icing shape to streamline icing shape with LWC increasing under the temperature of ?18?C. The icing accretes on blade surface layer by layer with icing time increasing. The closer the section blade tip, the more icing accretes. This study can be as reference for the research on anti-icing and de-icing technologies for large-scale HAWT.

Temperature effect on icing distribution near blade tip of large-scale horizontal-axis wind turbine by numerical simulation

To investigate the temperature effect on characteristics of icing distribution near the tip part of rotating blade of large-scale horizontal-axis wind turbine, numerical simulations were carried out on a horizontal-axis wind turbine rotor with rated power of 1.5 MW based on a quasi-three-dimensional computational method developed in this study. The icing simulation was focused on the part between blade tip and 30% length of blade from tip along span wise to blade root where the most serious icing area is according to the past researches. Eight sections along blade were selected, and the ice accretion on each airfoil was calculated. Eight temperature values from −6°C to −20°C were decided to investigate the effects of temperature on icing under the certain liquid water content and medium volume droplet. Three icing times were selected to research the ice accretion on blade surface with the increase in the time. According to the results, the icing distribution has the overall characteristics that the icing shape changes from horn icing shape to streamline icing shape with decrease in the temperature. The closer the blade airfoil section to blade tip, the more obvious the ice accretion is. This study can be a reference for the research on anti-icing and de-icing technologies for large-scale horizontal-axis wind turbine.

Electrical characteristics of conductive ultrathin bonded wearing course for active deicing and snow melting

ABSTRACTActive deicing and snow melting technologies, such as conductive asphalt concrete and heating cable, have got extensively concerned, however they are not applicable to the existing roads. Therefore, the conductive ultrathin bonded wearing course (CUBWC) is proposed, which mainly consists of the conductive functional layer (CFL) and gravel wearing course. The CFL is prepared by blending the graphite, carbon fibre (CF) and epoxy resin adhesive. To get the optimal electrical characteristics of CUBWC, the effects of CF length, CF content and graphite content on the resistivity of CFL were measured. The temperature sensitivity test and the temperature cycling test were further conducted to evaluate the temperature sensitive property and stability of CUBWC. Finally, the optimal contents of the graphite (25% by mass) and CF (4% by mass) were determined by considering the effective electrical conductivity and temperature stability of CUBWC.

An effect assessment and prediction method of ultrasonic de-icing for composite wind turbine blades

Abstract Wind turbines operating in cold and moist climates often suffer from icing events. Ice accretion on wind turbine blades threatens safe operation of wind turbines. Additionally, this phenomenon results in deterioration in power performance, which undoubtedly leads to economic losses. Ultrasonic guided wave anti-/de-icing technology has advantages of low energy consumption, light weight and low cost. However, there are few systematic methods to evaluate the de-icing effect of ultrasonic de-icing system on composite wind turbine blades. In this paper, an integrated and systematic method for the assessment and prediction of ultrasonic de-icing effect for composite wind turbine blades was proposed. Firstly, the interface integrity extent (IIE) and its rate of change were defined to describe the ice de-bonding behavior. Secondly, the adhesive strength of ice on the composite surface was measured, and an ultrasonic de-icing experiment was carried out. Thirdly, the optimal frequency for this de-icing system was calculated, and the stress distribution in the interface was obtained using numerical simulations. Finally, after determining the rate of change of IIE and carrying out the parameter fitting, the method for the assessment and prediction of ultrasonic de-icing effect was established. This method provides guidance for the design of ultrasonic de-icing systems.

Experiment investigation on deicing characteristics and energy efficiency using infrared ray as heat source

The adhesion and accretion of ice on ground aircraft always pose potential problem to aircraft engine operation and safety performance. Currently, chemical deicing technology is often used for aircraft deicing. However, it is effective, but not environmental-friendly, cost-effectively and always compromises material performance of aircraft. Infrared ray (IR) deicing technology, by contrast, is proved to be a promising deicing technology due to its high efficiency, safety performance and environment protection. However, the energy efficiency of IR deicing technology and physical process of ice melt have not been fully researched and understood. It is therefore necessary to study them to improve the IR deicing performances. In this paper, some important characteristics of IR deicing were firstly investigated, including ice melt rate, variation of ice temperatures and mass. Secondly, the heat transfer mechanism through whole deicing process was studied. Finally, based on the experiment results, the energy efficiency of IR deicing was calculated and discussed. And the studied results showed that the maximum energy efficiency of IR deicing could reach 53.1% at the highest setting temperature 2273 K. For melting 6.5 kg ice, the melt time was 1746 s and 1002 s at setting temperature 1073 K and 2073 K, respectively.

Review of marine icing and anti-/de-icing systems

ABSTRACTThe aim of this work is to review the phenomenon of icing in marine operations. The focus is on two main sources of icing, namely atmospheric and sea spray. The literature reveals that sea spray icing is the main contributor to marine icing. This work discusses the available ice accretion prediction models on ships and offshore structures. It also reviews the anti-/de-icing technologies that can be implemented on ships operating in cold climate regions. The significance of ice detection is acknowledged, and a brief review of various ice detection technologies is provided.

RESEARCH AND EXPERIMENT OF THERMAL WATER DE-ICING DEVICE

By analyzing the deficiencies of existing de-icing methods, a new de-icing method which combines thermal de-icing with water-jet cutting de-icing technology is coming into being. This paper introduces the construction of thermal water-jet de-icing equipment. Through repeated experiments, the factors which would affect de-icing have been researched and experimentally verified, including jet pressure, nozzle aperture, standoff, and jet injection angles, etc. Analysis of experimental results shows that this device can perform well and satisfy design requirements.

The Design of the High Tension Line Mechanical Deicing Unit

In recent years, our country south parts of the rain and snow freeze disaster occurred frequently, which resulted in increased surface of the transmission line icing, gravity, high voltage transmission line widespread damage. In order to avoid the high tension line crushed, to guarantee the normal electricity, you need to clear the ice on the high tension line in time. Through the analysis of all kinds of existing de-icing technology advantages and disadvantages, put forward in this paper, the high tension line of mechanical deicing unit. Paper first puts forward the overall scheme of deicing unit needed to solve in the design of the main problems, and then expounds the axis and in addition to the design and calculation of the ice skates finally, and locking mechanism and regulating mechanism and so on the design of mechanical parts.

Efficiency Analysis on the Synthetically De-Icing Technology Combining Thermal Water-Jet Cutting with Mechanical Milling

Transportation always plays a significant role in national economy, of which roads and bridges are the most important facilities. The conditions of the road surface have an overwhelming influence on the traffic flow and road safety, especially in winter and the regions with frequent snowfall, thus closely affected the development of the urbanization and economic prosperity. In view of this, this article has analyzed the characteristics of the existed de-icing technologies, coming up with a new synthetically de-icing method which consists of thermal water-jet cutting with mechanical milling technology. These two kinds of de-icing methods are combined as a set of multi-functional system, in which the thermal water-jet cuts the ice layer into separated sections, and the mechanical milling unit then easily removes the remaining sections out of the road. To obtain the prime influential factors in this new de-icing device, repeated indoor experiments were conducted, which provides some theoretical references to further advance the de-icing efficiency and make structural optimization.

Design and Experiment of Thermal Water and Mechanical Deicing Device

Fast and economical removal of icing snow on the airport runways, road, highways and other roads is a problem for reducing traffic accident rate in frozen weather. Based on the analysis of current researches on various deicing methods, a new deicing method that combines thermal deicing method, water-jet cutting with mechanical deicing technology was presented. This context introduces the construction and working principle of this device, and milling cutting model was constructed, power calculation of milling equipment is also carried out. Subsequently, indoor experiments results was repeated. The feasibility of this scheme is validated by experiments of the compound equipment.

Ultrasonic De-Icing Bondline Design and Rotor Ice Testing

The use of ultrasonic excitation has shown the ability to promote ice shedding of impact ice (less than 2 mm thick) during prior wind-tunnel testing efforts. The ultrasonic de-icing technology is implemented to structures representative of rotorcraft blade leading edges and tested under impact icing and centrifugal environments (). Finite element models are experimentally validated and used to predict the ultrasonic ice shedding transverse shear stresses responsible for ice shedding. The finite element models tools are then used to guide the design of a robust bondline between the lead zirconate titanate actuators and the host structure. The novel bondline approach is implemented to a rotor blade leading-edge erosion cap representative structure (0.813-mm-thick stainless-steel leading edge). The system is tested under centrifugal loads and icing conditions generic to helicopter operational envelopes. Details on the de-icing system fabrication and integration are provided. The bondline configuration does not degrade during operation and increases the ice interface transverse shear stresses by 15% with respect to prior bonding approaches. To promote ice shedding of impact ice, a system control to identify and excite optimum de-icing modes during rotor ice testing is also implemented and described in this paper. The power consumption of the de-icing system is quantified to average . The de-icing system is able to promote shedding of ice layers ranging from 1.4 to 7.1 mm in thickness for varying icing conditions representative of helicopter icing environments.

Automatic Controls for the Carbon Fiber Tape-Based Deicing Technology

Snow and ice on roads are hazardous. Many methods are applied for road surface deicing. Most of these methods, however, suffer from one or more of the following shortcomings: low energy efficiency, large labor requirements, high cost, or potential to damage roads. This paper presents the design of automatic controllers and the analysis of their efficiency as applied in a carbon fiber tape (CFT)-based resistive heating deicing technology. Two automatic controllers based on surface temperature—an on-off controller and a fuzzy logic-based controller—are implemented in an experimental deicing facility with CFT-based deicing technology. The fuzzy logic-based controller retrieves the weather forecast information and considers many different scenarios. A LabVIEW interface is used for remote monitoring of the deicing process. The experimental results show that both types of automatic controllers are very effective in preventing the ice from forming on the sidewalk surface, and both are significantly more efficient than manual control in terms of operating cost, with the fuzzy logic-based controller being the most efficient. The fuzzy logic-based controller represents the major technical contribution of this paper, and with certain adaptation, it is also applicable for other resistive heating-based deicing technologies.

Research and Application of DC De–Icing Technology in China Southern Power Grid

Ice-clad transmission lines can seriously damage a power grid, causing a partial or entire breakdown. De-icing the transmission line is a good method to prevent recurrence of such a situation. The development of dc de-icing technology can make difference in power grids preventing an ice disaster. Based on the calculation, analysis, and tests in the artificial climate chamber of the conductor de-icing parameters, the dc de-icing technical scheme for the typical transmission lines at various voltage levels in China Southern Power Grid is proposed. Two economical and practical topological structures of the dc de-icer have been proposed, and the prototypes have been developed and tested in the field successfully. Then, the defensive strategy of the power grid for ice disaster based on dc dicers is proposed. The application during the icing season of 2009-2012 in China shows that the dc de-icing method is an effective means to prevent an ice disaster in the power grid.

A Study on De-Icing Technology for Electric Transmission Line

The article aims to analyze kinds of de-icing methods in detail with the present condition that the transmission lines often suffered serious damage with the deep ice over them. It also points out the development trend of de-icing technology in the next years and provides some advices for the de-icing research work of transmission line in our country.

Experimental Study on Carbon Fiber Tape–Based Deicing Technology

In cold regions, snow and ice cause serious safety problems to the transportation system. South central Alaska, particularly Anchorage, is susceptible to a number of icing events resulting from frequent freeze/thaw cycles in the winter season. Traditionally, deicing has been accomplished by mechanical, chemical, and thermal methods. However, these methods cause problems such as damage to pavement, pollution in the environment, corrosion to vehicles and reinforcing steel in concrete, or being too expensive. A new type of roadway deicing system on the basis of commercially available carbon fiber tape is proposed. This paper presents the design of a deicing heating panel, the layout and construction of the test sidewalk, experimental results and analyses, and cost comparison with other deicing systems. Experimental results including system performance, deicing time, energy consumption, deicing cost, and temperature variation with time and location are presented. The sensitivity of the deicing cost to ambient air temperature, wind chill, and snow density is also analyzed. Finally, this system is compared with other deicing systems in annual operating cost, unit cost, power density, and installation cost. The cost comparison shows that the present deicing system demonstrates higher energy efficiency and lower installation cost among the systems compared and has great potential for applications in cold regions.

Research Situation and Prospect for Highway Snowmelt Deicing Technology with Electric Heat Tracing

The frequency of worldwide disastrous weather is intensified by the global climate warming. The disastrous weather such as freezing rain and snow is extremely disadvantageous to the vehicle performance and safety. This paper summarizes and classifies the current snowmelt deicing methods at home and abroad; emphatically proposes the trend of future active development for snowmelt technology and introduces the snowmelt deicing technology of electric heat tracing, which is the competed developing new technology in the countries of cold region acting as one of the snow removal measures in winter cold regions. The electro-thermal snowmelt deicing technology involves relatively wider field of knowledge, whose research and development are also increasingly connected with the development of other technologies. This paper reviews the development history of electro-thermal snowmelt deicing technology and summarizes the main research condition of domestic electro-thermal snowmelt deicing technology in the last few years, furthermore looks forward the development and application prospect of electro-thermal snowmelt deicing technology by brief description of the current research situation.

Development and Application of Capacitor Compensation AC De-Icing Equipment

Considering that conventional AC de-icing method has many shortcomings such as complicated braking operation and difficult arrangement for power operation modes, we propose the new AC de-icing technology using capacitor compensation. On this basis, a novel regulative capacitor series-wound compensating AC de-icing equipment is developed, which works through controlling the line current to be within the permitted range in order to melt the ice. By the unique design mechanism of changing the series-parallel connection modes of capacitor combination and capacitor number for each combination, this equipment can make reasonable compensation for transmission line of arbitrary length within 40 km. Field test at JiLi 220kV substation of Hunan province manifests that this new-style AC de-icing equipment has remarkable effect with low energy consumption, simple operation and low engineering cost, thus has bright prospects of engineering application.

Microwave De-/Anti-Icing Using the Midas-Technology

For aviation, a suitable alternative for currently used in-flight anti-/de-icing technologies for today’s aircrafts with metal structures and future aircrafts with replaced composite structures is necessary. Intense investigations performed at FZK have been together in collaboration with aircraft manufacturers to design and develop a new avionic microwave technology for monolithic composite structures.The full system integration has been evaluated for several airplanes considering the structural and efficiency demands. The concept of this MIDAS (Microwave Deicing Anti-icing System) technology as well their recent results will be presented. A full system integration has been tested and is visualized in the paper.