WorldWideScience

Sample records for anti-icing

  1. Environmentally friendly anti-icing

    Science.gov (United States)

    Lockyer, Robert T. (Inventor); Zuk, John (Inventor); Haslim, Leonard A. (Inventor)

    1998-01-01

    The present invention describes an aqueous, non-electrolytic, non-toxic, biodegradable, continuous single phase liquid anti-icing or deicing composition for use on the surfaces of, for example, aircraft, airport pavements, roadways, walkways, bridges, entrances, structures, canals, locks, components, vessels, nautical components, railroad switches, and motor vehicles. The anti-icing or deicing composition comprises: (a) water; (b) a non-toxic freezing point depressant selected from the group consisting of monohydric alcohols having from 2 to 6 carbon atoms, polyhydric alcohols having from 3 to 12 carbon atoms, monomethyl or ethyl ethers of polyhydric alcohols having from 3 to 12 atoms or mixtures thereof, wherein the freezing point depressant present is between about 14 to 60 percent by weight; (c) a thickener which is present in between about 0.01 and 10 percent by weight; and (d) optionally a corrosion inhibitor which is present in between about 0.01 and 0.1 percent by weight of the total composition. In one embodiment, the deicing composition further includes (e) a monohydric primary aliphatic unbranched alcohol as a means of forming a thin layer of the composition on the surface of the structure to be given ice protection, and/or as means of forming a homogenized foam with xanthan thickener; which alcohol is selected from the group consisting of alcohols having between 8 to 24 carbon atoms, preferably, 1-dodecanol. Compositions of water, propylene glycol, and/or propanol and xanthan are preferred.

  2. Anti-icing performance of superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Farhadi, S.; Farzaneh, M. [CIGELE/INGIVRE, Department of Applied Sciences, Universite du Quebec a Chicoutimi, 555 University blvd., Saguenay, PQ, G7H 2B1 (Canada); Kulinich, S.A., E-mail: skulinic@uqac.ca [CIGELE/INGIVRE, Department of Applied Sciences, Universite du Quebec a Chicoutimi, 555 University blvd., Saguenay, PQ, G7H 2B1 (Canada)

    2011-05-01

    This article studies the anti-ice performance of several micro/nano-rough hydrophobic coatings with different surface chemistry and topography. The coatings were prepared by spin-coating or dip coating and used organosilane, fluoropolymer or silicone rubber as a top layer. Artificially created glaze ice, similar to the naturally accreted one, was deposited on the nanostructured surfaces by spraying supercooled water microdroplets (average size {approx}80 {mu}m) in a wind tunnel at subzero temperature (-10 deg. C). The ice adhesion strength was evaluated by spinning the samples in a centrifuge at constantly increasing speed until ice delamination occurred. The results show that the anti-icing properties of the tested materials deteriorate, as their surface asperities seem to be gradually broken during icing/de-icing cycles. Therefore, the durability of anti-icing properties appears to be an important point for further research. It is also shown that the anti-icing efficiency of the tested superhydrophobic surfaces is significantly lower in a humid atmosphere, as water condensation both on top and between surface asperities takes place, leading to high values of ice adhesion strength. This implies that superhydrophobic surfaces may not always be ice-phobic in the presence of humidity, which can limit their wide use as anti-icing materials.

  3. Deicing and Anti-Icing Unite

    Science.gov (United States)

    2002-01-01

    With funding from Glenn's Small Business Innovation Research (SBIR) program, Cox & Company, Inc., built an ice protection system that combines thermal anti-icing and mechanical deicing to keep airfoils (wings and other lifting surfaces) clear of ice. Cox's concept was to combine an anti-icing system with NASA's Electro-Mechanical Expulsion Deicing System, a mechanical deicer. The anti-icing element of this hybrid would reduce the aerodynamic losses associated with deicing systems. The Cox Low Power Ice Protection System is the first new aircraft ice protection system that has been approved by the Federal Aviation Administration for use on a business jet in 40 years. While the system is currently sized for Premier class aircraft, there are no apparent constraints prohibiting its use on aircraft of any size. The company is investigating further applications, such as adapting the system for unmanned aerial vehicles and other military aircraft.

  4. Passive Anti-Icing and Active Deicing Films.

    Science.gov (United States)

    Wang, Tuo; Zheng, Yonghao; Raji, Abdul-Rahman O; Li, Yilun; Sikkema, William K A; Tour, James M

    2016-06-08

    Anti-icing and deicing are the two major pathways for suppressing adhesion of ice on surfaces, yet materials with dual capabilities are rare. In this work, we have designed a perfluorododecylated graphene nanoribbon (FDO-GNR) film that takes advantage of both the low polarizability of perfluorinated carbons and the intrinsic conductive nature of graphene nanoribbons. The FDO-GNR films are superhydrophobic with a sheet resistance below 8 kΩ·sq(-1) and then exhibit an anti-icing property that prevents freezing of incoming ice-cold water down to -14 °C. After that point, voltage can be applied to the films to resistively heat and deice the surface. Further a lubricating liquid can be employed to create a slippery surface to improve the film's deicing performance. The FDO-GNR films can be easily switched between the superhydrophobic anti-icing mode and the slippery deicing mode by applying the lubricant. A spray-coating method makes it suitable for large-scale applications. The anti-icing and deicing properties render the FDO-GNR films with promise for use in extreme environments.

  5. Superhydrophilic Polyelectrolyte Brush Layers with Imparted Anti-Icing Properties

    DEFF Research Database (Denmark)

    Chernyy, Sergey; Järn, Mikael; Shimizu, Kyoko;

    2014-01-01

    This work demonstrates the feasibility of superhydrophilic polyelectrolyte brush coatings for anti-icing applications. Five different types of ionic and nonionic polymer brush coatings of 25-100 nm thickness were formed on glass substrates using silane chemistry for surface premodification followed......(-), SO4(2-), and C12SO3(-) ions. By consecutive measurements of the strength of ice adhesion toward ion-incorporated polymer brushes on glass it was found that Li(+) ions reduce ice adhesion by 40% at -18 °C and 70% at -10 °C. Ag(+) ions reduce ice adhesion by 80% at -10 °C relative to unmodified glass....... In general, superhydrophilic polyelectrolyte brushes exhibit better anti-icing property at -10 °C compared to partially hydrophobic brushes such as poly(methyl methacrylate) and surfactant exchanged polyelectrolyte brushes. The data are interpreted using the concept of a quasi liquid layer (QLL...

  6. Aerodynamic Effects Of Deicing And Anti-Icing Fluids

    Science.gov (United States)

    Addy, Harold E., Jr.; Runyan, L. James; Zierten, Thomas A.; Hill, Eugene G.

    1994-01-01

    Report presents results of wind-tunnel tests of aerodynamic effects of deicing and anti-icing fluids on airplane wings. Tests conducted on three-dimensional half-model airplane and two-dimensional airfoil model at temperatures ranging from -29 to +10 degrees C. Fluids used included three commercial fluids available for use during 1987-1988 winter season, one discontinued commercial fluid, and eight newer fluids experimental at time of test.

  7. Anti-icing Behavior of Thermally Sprayed Polymer Coatings

    Science.gov (United States)

    Koivuluoto, Heli; Stenroos, Christian; Kylmälahti, Mikko; Apostol, Marian; Kiilakoski, Jarkko; Vuoristo, Petri

    2017-01-01

    Surface engineering shows an increasing potential to provide a sustainable approach to icing problems. Currently, several passive anti-ice properties adoptable to coatings are known, but further research is required to proceed for practical applications. This is due to the fact that icing reduces safety, operational tempo, productivity and reliability of logistics, industry and infrastructure. An icing wind tunnel and a centrifugal ice adhesion test equipment can be used to evaluate and develop anti-icing and icephobic coatings for a potential use in various arctic environments, e.g., in wind power generation, oil drilling, mining and logistic industries. The present study deals with evaluation of icing properties of flame-sprayed polyethylene (PE)-based polymer coatings. In the laboratory-scale icing tests, thermally sprayed polymer coatings showed low ice adhesion compared with metals such as aluminum and stainless steel. The ice adhesion strength of the flame-sprayed PE coating was found to have approximately seven times lower ice adhesion values compared with metallic aluminum, indicating a very promising anti-icing behavior.

  8. Anti-icing Behavior of Thermally Sprayed Polymer Coatings

    Science.gov (United States)

    Koivuluoto, Heli; Stenroos, Christian; Kylmälahti, Mikko; Apostol, Marian; Kiilakoski, Jarkko; Vuoristo, Petri

    2016-12-01

    Surface engineering shows an increasing potential to provide a sustainable approach to icing problems. Currently, several passive anti-ice properties adoptable to coatings are known, but further research is required to proceed for practical applications. This is due to the fact that icing reduces safety, operational tempo, productivity and reliability of logistics, industry and infrastructure. An icing wind tunnel and a centrifugal ice adhesion test equipment can be used to evaluate and develop anti-icing and icephobic coatings for a potential use in various arctic environments, e.g., in wind power generation, oil drilling, mining and logistic industries. The present study deals with evaluation of icing properties of flame-sprayed polyethylene (PE)-based polymer coatings. In the laboratory-scale icing tests, thermally sprayed polymer coatings showed low ice adhesion compared with metals such as aluminum and stainless steel. The ice adhesion strength of the flame-sprayed PE coating was found to have approximately seven times lower ice adhesion values compared with metallic aluminum, indicating a very promising anti-icing behavior.

  9. Characterization method of hydrophobic anti-icing coatings

    Science.gov (United States)

    Morita, Katsuaki; Sakaue, Hirotaka

    2015-11-01

    For anti-icing, supercooled water should be removed before frozen onto the contact surface. We use a hydrophobic coating for anti-icing and introduce the static- and dynamic-evaluation methods. The methods describe the contact surface between the hydrophobic surface and a supercooled-water droplet. The former is based on the contact angle, and the latter is based on the sliding angle. The temperature factor is included in these models to evaluate the hydrophobic coating under the supercooled conditions. Four hydrophobic coatings are experimentally evaluated based on the static- and dynamic evaluation methods: C1-C3 (commercial fluorocarbon coatings), and Jaxa coating (original fluorocarbon coating). These are evaluated under the supercooled conditions of -10 to 0 °C. The static-evaluation shows variations in the temperature. However, change in the contact angle by the temperature is relatively small compared to that of the sliding angle for the dynamic evaluation. Only C3 and Jaxa coatings are tolerant to the sliding angle under the supercooled conditions tested. The dynamic evaluation shows that even if the coating is hydrophobic, the dynamic evaluation should be included to understand the characteristic of removal for a supercooled-water droplet.

  10. Resistance Allocation Plan of Semiconducting Silicone Rubber Applied to Insulators for Anti-icing

    Institute of Scientific and Technical Information of China (English)

    WEI Xiaoxing; JIA Zhidong; SUN Zhenting; GUAN Zhicheng; ZHAO Yuming

    2012-01-01

    The anti-icing and de-icing methods of insulator strings are still under laboratory studies while many technologies are applied in operation to overhead conductors. The anti-icing method using semiconducting silicone rubber coating applied to the bottom side of the insulators could get good results in a climate chamber. However, the resistance of the coating is an important factor influencing the anti-icing performance of the coated insulators. Thus the coating resistance should be determined. A heating analytical method of insulators with semiconducting silicone rubber (SIR) is proposed.

  11. Characterization of hydrophobic and hydrophilic coatings as deicing and anti-icing

    Science.gov (United States)

    Aoki, Akihito; Morita, Katsuaki; Konno, Akihisa; Sakaue, Hirotaka

    2010-11-01

    Anti-icing is necessary in various fields, such as aeronautics, roads, power lines, ships, and architectures. Deicing fluids, and sometimes hot water, work to prevent from icing. Due to environmental issue, deicing fluids are not always welcome to use. We study hydrophobic and hydrophilic coatings for anti-icing. By coating these to a target surface, it prevents icing without damaging the environment. We present a characterization method of hydrophobic and hydrophilic coatings for deicing and anti-icing. We provide a temperature-control room to create an icing condition, such as -10 to 0 degrees C. Under the controlled room, the contact angle measurement as well as the force measurement is employed. Total 15 coatings are characterized. Based on the tests of all coatings, we propose a combined coating from some characterized ones.

  12. Bridge ice accretion and de- and anti-icing systems: A review

    DEFF Research Database (Denmark)

    Kleissl, Kenneth; Georgakis, Christos

    2010-01-01

    Blocks of ice or snow falling from bridge members can cause traffic accidents, direct damages to passing vehicles, and generally place human safety at risk. Consequently, the lack of successful de- or anti-icing measures may result in bridge closure, which leads to traffic hindrance that can...

  13. Fabrication and anti-icing property of coral-like superhydrophobic aluminum surface

    Science.gov (United States)

    Zuo, Zhiping; Liao, Ruijin; Guo, Chao; Yuan, Yuan; Zhao, Xuetong; Zhuang, Aoyun; Zhang, YiYi

    2015-03-01

    Aluminum is one of the most widely used metals in transmission lines. Accumulation of ice on aluminum may cause serious consequences such as tower collapse and power failure. Here we develop a method to fabricate a coral-like superhydrophobic surface to improve its anti-icing performance via chemical etching and hot-water treatment. The as-prepared surface exhibited superhydrophobicity with a contact angle (CA) of 164.8 ± 1.1° and the sliding angle smaller than 1°. The static and dynamic anti-icing behaviors of the superhydrophobic surface in different conditions were systematically investigated using a self-made device and artificial climate laboratory. Results show that the coral-like superhydrophobic structure displayed excellent anti-icing property. The water droplet remained unfrozen on the as-prepared surface at -6 °C for over 110 min. 71% of the surface was free of ice when exposed in "glaze ice" for 30 min. This investigation proposed a new way to design an anti-icing surface which may have potential future applications in transmission lines against ice accumulation.

  14. Anti-icing properties of superhydrophobic ZnO/PDMS composite coating

    Science.gov (United States)

    Yang, Chao; Wang, Fajun; Li, Wen; Ou, Junfei; Li, Changquan; Amirfazli, Alidad

    2016-01-01

    We present the excellent anti-icing performance for a superhydrophobic coating surface based on ZnO/polydimethylsiloxane (ZnO/PDMS) composite. The superhydrophobic ZnO/PDMS coating surface was prepared by a facile solution mixing, drop coating, room-temperature curing and surface abrading procedure. The superhydrophobic ZnO/PDMS composite coating possesses a water contact angle of 159.5° and a water sliding angle of 8.3° at room temperature (5 °C). The anti-icing properties of the superhydrophobic coating were investigated by continuously dropping cold-water droplets (about 0 °C) onto the pre-cooled surface using a home-made apparatus. The sample was placed at different tilting angle (0° and 10°) and pre-cooled to various temperatures (-5, -10 and -15 °C) prior to measure. The pure Al surface was also studied for comparison. It was found that icing accretion on the surface could be reduced apparently because the water droplets merged together and slid away from the superhydrophobic surface at all of the measuring temperatures when the surface is horizontally placed. In addition, water droplet slid away completely from the superhydrophobic surface at -5 and -10 °C when the surface is tilted at 10°, which demonstrates its excellent anti-icing properties at these temperatures. When the temperature decreased to -15 °C, though ice accretion on the tilted superhydrophobic coating surface could not be avoided absolutely, the amount of ice formed on the surface is very small, which indicated that the coating surface with superhydrophobicity could significantly reduce ice accumulation on the surface at very low temperature (-15 °C). Importantly, the sample is also stable against repeated icing/deicing cycles. More meaningfully, once the superhydrophobic surface is damaged, it can be repaired easily and rapidly.

  15. The Effect of Break Edge Configuration on the Aerodynamics of Anti-Ice Jet Flow

    Directory of Open Access Journals (Sweden)

    Tatar V.

    2015-01-01

    Full Text Available One of the components of a turboprop gas turbine engine is the Front Bearing Structure (FBS which leads air into the compressor. FBS directly encounters with ambient air, as a consequence ice accretion may occur on its static vanes. There are several aerodynamic parameters which should be considered in the design of anti-icing system of FBS, such as diameter, position, exit angle of discharge holes, etc. This research focuses on the effects of break edge configuration over anti-ice jet flow. Break edge operation is a process which is applied to the hole in order to avoid sharp edges which cause high stress concentration. Numerical analyses and flow visualization test have been conducted. Four different break edge configurations were used for this investigation; without break edge, 0.35xD, 74xD, 0.87xD. Three mainstream flow conditions at the inlet of the channel are defined; 10m/s, 20 m/s and 40 m/s. Shear stresses are extracted from numerical analyses near the trailing edge of pressure surface where ice may occur under icing conditions. A specific flow visualization method was used for the experimental study. Vane surface near the trailing edge was dyed and thinner was injected into anti-ice jet flow in order to remove dye from the vane surface. Hence, film effect on the surface could be computed for each testing condition. Thickness of the dye removal area of each case was examined. The results show noticeable effects of break edge operation on jet flow, and the air film effectiveness decreases when mainstream inlet velocity decreases.

  16. The Effect of Break Edge Configuration on the Aerodynamics of Anti-Ice Jet Flow

    Science.gov (United States)

    Tatar, V.; Yildizay, H.; Aras, H.

    2015-05-01

    One of the components of a turboprop gas turbine engine is the Front Bearing Structure (FBS) which leads air into the compressor. FBS directly encounters with ambient air, as a consequence ice accretion may occur on its static vanes. There are several aerodynamic parameters which should be considered in the design of anti-icing system of FBS, such as diameter, position, exit angle of discharge holes, etc. This research focuses on the effects of break edge configuration over anti-ice jet flow. Break edge operation is a process which is applied to the hole in order to avoid sharp edges which cause high stress concentration. Numerical analyses and flow visualization test have been conducted. Four different break edge configurations were used for this investigation; without break edge, 0.35xD, 74xD, 0.87xD. Three mainstream flow conditions at the inlet of the channel are defined; 10m/s, 20 m/s and 40 m/s. Shear stresses are extracted from numerical analyses near the trailing edge of pressure surface where ice may occur under icing conditions. A specific flow visualization method was used for the experimental study. Vane surface near the trailing edge was dyed and thinner was injected into anti-ice jet flow in order to remove dye from the vane surface. Hence, film effect on the surface could be computed for each testing condition. Thickness of the dye removal area of each case was examined. The results show noticeable effects of break edge operation on jet flow, and the air film effectiveness decreases when mainstream inlet velocity decreases.

  17. Durability of a lubricant-infused Electrospray Silicon Rubber surface as an anti-icing coating

    Science.gov (United States)

    Liu, Qi; Yang, Ying; Huang, Meng; Zhou, Yuanxiang; Liu, Yingyan; Liang, Xidong

    2015-08-01

    Slippery liquid-infused porous surfaces (SLIPS) are attracting great interest as anti-icing coatings. However, the most challenging point for SLIPS is their durability. A heptadecafluorodecyl trimethoxysilane-fluorinated hierarchically micro-structured silicone rubber surface was prepared by electrospray method coupled with phase separation which had a contact angle of the lubricant θls(a) = 0°. This study investigated the effects of the surface chemistry, length scale and hierarchy of the surface topography of the underlying substrates on their ability to retain the lubricant during repetitive icing/deicing, water washout and ice-shedding treatments. This study compares the lubricant retention rate, ice formation time and ice adhesion strength. The result demonstrated that SLIPS with a fluorinated hierarchical micro/nano scale substrate maintains the best anti-icing capability. Lubricant in the microscale pores can easily creep up to the surface with nano-scale pores providing stronger capillary forces to hold the lubricant in the pores only if θls(a) = 0° with a rolling hill pattern lubricant surface morphology formed during the loss of lubricant. Such fluorinated hierarchically nano/micro structured substrate will enable the lubricant to completely cover the surface which reduces heterogeneous nucleation and frost propagation velocity.

  18. Numerical Modeling of Anti-icing Systems and Comparison to Test Results on a NACA 0012 Airfoil

    Science.gov (United States)

    Al-Khalil, Kamel M.; Potapczuk, Mark G.

    1993-01-01

    A series of experimental tests were conducted in the NASA Lewis IRT on an electro-thermally heated NACA 0012 airfoil. Quantitative comparisons between the experimental results and those predicted by a computer simulation code were made to assess the validity of a recently developed anti-icing model. An infrared camera was utilized to scan the instantaneous temperature contours of the skin surface. Despite some experimental difficulties, good agreement between the numerical predictions and the experiment results were generally obtained for the surface temperature and the possibility for each runback to freeze. Some recommendations were given for an efficient operation of a thermal anti-icing system.

  19. Scaling of Lift Degradation Due to Anti-Icing Fluids Based Upon the Aerodynamic Acceptance Test

    Science.gov (United States)

    Broeren, Andy P.; Riley, James T.

    2012-01-01

    In recent years, the FAA has worked with Transport Canada, National Research Council Canada (NRC) and APS Aviation, Inc. to develop allowance times for aircraft operations in ice-pellet precipitation. These allowance times are critical to ensure safety and efficient operation of commercial and cargo flights. Wind-tunnel testing with uncontaminated anti-icing fluids and fluids contaminated with simulated ice pellets had been carried out at the NRC Propulsion and Icing Wind Tunnel (PIWT) to better understand the flowoff characteristics and resulting aerodynamic effects. The percent lift loss on the thin, high-performance wing model tested in the PIWT was determined at 8 angle of attack and used as one of the evaluation criteria in determining the allowance times. Because it was unclear as to how performance degradations measured on this model were relevant to an actual airplane configuration, some means of interpreting the wing model lift loss was deemed necessary. This paper describes how the lift loss was related to the loss in maximum lift of a Boeing 737-200ADV airplane through the Aerodynamic Acceptance Test (AAT) performed for fluids qualification. A loss in maximum lift coefficient of 5.24 percent on the B737-200ADV airplane (which was adopted as the threshold in the AAT) corresponds to a lift loss of 7.3 percent on the PIWT model at 8 angle of attack. There is significant scatter in the data used to develop the correlation related to varying effects of the anti-icing fluids that were tested and other factors. A statistical analysis indicated the upper limit of lift loss on the PIWT model was 9.2 percent. Therefore, for cases resulting in PIWT model lift loss from 7.3 to 9.2 percent, extra scrutiny of the visual observations is required in evaluating fluid performance with contamination.

  20. Optimization via CFD of aircraft hot-air anti-icing systems

    Science.gov (United States)

    Pellissier, Mathieu Paul Constantin

    In-flight icing is a major concern in aircraft safety and a non-negligible source of incidents and accidents, and is still a serious hazard today. It remains consequently a design and certification challenge for aircraft manufacturers. The aerodynamic performance of an aircraft can indeed degrade rapidly when flying in icing conditions, leading to incidents or accidents. In-flight icing occurs when an aircraft passes through clouds containing supercooled water droplets at or below freezing temperature. Droplets impinge on its exposed surfaces and freeze, causing roughness and shape changes that increase drag, decrease lift and reduce the stall angle of attack, eventually inducing flow separation and stall. This hazardous ice accretion is prevented by the use of dedicated anti-icing systems, among which hot-air-types are the most common for turbofan aircraft. This work presents a methodology for the optimization of such aircraft hot-air-type anti-icing systems, known as Piccolo tubes. Having identified through 3D Computational Fluid Dynamics (CFD) the most critical in-flight icing conditions, as well as determined thermal power constraints, the objective is to optimize the heat distribution in such a way to minimize power requirements, while meeting or exceeding all safety regulation requirements. To accomplish this, an optimization method combining 3D CFD, Reduced-Order Models (ROM) and Genetic Algorithms (GA) is constructed to determine the optimal configuration of the Piccolo tube (angles of jets, spacing between holes, and position from leading edge). The methodology successfully results in increasingly optimal configurations from three up to five design variables.

  1. Ice Accretion on Wires and Anti-Icing Induced by Joule Effect.

    Science.gov (United States)

    Personne, P.; Gayet, J.-F.

    1988-02-01

    This study concerns both the formation of ice accreted around wires due to rotation from gravitational and aerodynamic forces, and the anti-icing induced by the Joule effect. The experiments have been carried out in an instrumented wind tunnel operating in natural conditions. The results show that the growth rate increases with the ice deposit thickness. Because of low airspeed and small cloud droplets, the total collection efficiency is less than 0.2. The discrepancies between the observed collection efficiencies and those predicted by Langmuir and Biodgett's theory increase with time and consequently with the ice thickness. This may be due to the complex shape of the deposit which is noncircular and presents a rough surface. These results point out the difficulties in modeling the detail of such ice profiles in this range of conditions. The air temperature plays a significant role in the rotation angle of the wire and in the ice growth rates. The surface temperature of wires is measured in order to validate the heat balance of the heated wires; this gives a proposed estimation of the current to prevent the wire from icing.

  2. Lewis icing research tunnel test of the aerodynamic effects of aircraft ground deicing/anti-icing fluids

    Science.gov (United States)

    Runyan, L. James; Zierten, Thomas A.; Hill, Eugene G.; Addy, Harold E., Jr.

    1992-01-01

    A wind tunnel investigation of the effect of aircraft ground deicing/anti-icing fluids on the aerodynamic characteristics of a Boeing 737-200ADV airplane was conducted. The test was carried out in the NASA Lewis Icing Research Tunnel. Fluids tested include a Newtonian deicing fluid, three non-Newtonian anti-icing fluids commercially available during or before 1988, and eight new experimental non-Newtonian fluids developed by four fluid manufacturers. The results show that fluids remain on the wind after liftoff and cause a measurable lift loss and drag increase. These effects are dependent on the high-lift configuration and on the temperature. For a configuration with a high-lift leading-edge device, the fluid effect is largest at the maximum lift condition. The fluid aerodynamic effects are related to the magnitude of the fluid surface roughness, particularly in the first 30 percent chord. The experimental fluids show a significant reduction in aerodynamic effects.

  3. A facile method of fabricating mechanical durable anti-icing coatings based on CeO2 microparticles

    Science.gov (United States)

    Wang, Pengren; Peng, Chaoyi; Wu, Binrui; Yuan, Zhiqing; Yang, Fubiao; Zeng, Jingcheng

    2015-07-01

    Compromising between hydrophobicity and mechanical durability may be a feasible approach to fabricating usable anti-icing coatings. This work improves the contact angle of current commercial anti-icing coatings applied to wind turbine blades dramatically and keeps relatively high mechanical durability. CeO2 microparticles and diluent were mixed with fluorocarbon resin to fabricate high hydrophobic coatings on the glass fiber reinforced epoxy composite substrates. The proportion of CeO2 microparticles and diluent influences the contact angles significantly. The optimum mass ratio of fluorocarbon resin to CeO2 microparticles to diluent is 1:1.5:1, which leads to the highest contact angle close to 140°. The microscopy analysis shows that the CeO2 microparticles form nano/microscale hierarchical structure on the surface of the coatings.

  4. Robust Slippery Coating with Superior Corrosion Resistance and Anti-Icing Performance for AZ31B Mg Alloy Protection.

    Science.gov (United States)

    Zhang, Jialei; Gu, Changdong; Tu, Jiangping

    2017-03-29

    Biomimetic slippery liquid-infused porous surfaces (SLIPSs) are developed as a potential alternative to superhydrophobic surfaces (SHSs) to resolve the issues of poor durability in corrosion protection and susceptibility to frosting. Herein, we fabricated a double-layered SLIPS coating on the AZ31 Mg alloy for corrosion protection and anti-icing application. The porous top layer was infused by lubricant, and the compact underlayer was utilized as a corrosion barrier. The water-repellent SLIPS coating exhibits a small sliding angle and durable corrosion resistance compared with the SHS coating. Moreover, the SLIPS coating delivers durable anti-icing performance for the Mg alloy substrate, which is obviously superior to the SHS coating. Multiple barriers in the SLIPS coating, including the infused water-repellent lubricant, the self-assembled monolayers coated porous top layer, and the compact layered double hydroxide-carbonate composite underlayer, are suggested as being responsible for the enhanced corrosion resistance and anti-icing performance. The robust double-layered SLIPS coating should be of great importance to expanding the potential applications of light metals and their alloys.

  5. Anti-icing property of bio-inspired micro-structure superhydrophobic surfaces and heat transfer model

    Science.gov (United States)

    Liu, Yan; Li, Xinlin; Jin, Jingfu; Liu, Jiaan; Yan, Yuying; Han, Zhiwu; Ren, Luquan

    2017-04-01

    Ice accumulation is a thorny problem which may inflict serious damage even disasters in many areas, such as aircraft, power line maintenance, offshore oil platform and locators of ships. Recent researches have shed light on some promising bio-inspired anti-icing strategies to solve this problem. Inspired by typical plant surfaces with super-hydrophobic character such as lotus leaves and rose petals, structured superhydrophobic surface are prepared to discuss the anti-icing property. 7075 Al alloy, an extensively used materials in aircrafts and marine vessels, is employed as the substrates. As-prepared surfaces are acquired by laser processing after being modified by stearic acid for 1 h at room temperature. The surface morphology, chemical composition and wettability are characterized by means of SEM, XPS, Fourier transform infrared (FTIR) spectroscopy and contact angle measurements. The morphologies of structured as-prepared samples include round hump, square protuberance and mountain-range-like structure, and that the as-prepared structured surfaces shows an excellent superhydrophobic property with a WCA as high as 166 ± 2°. Furthermore, the anti-icing property of as-prepared surfaces was tested by a self-established apparatus, and the crystallization process of a cooling water on the sample was recorded. More importantly, we introduced a model to analyze heat transfer process between the droplet and the structured surfaces. This study offers an insight into understanding the heat transfer process of the superhydrophobic surface, so as to further research about its unique property against ice accumulation.

  6. 飞机除冰/防冰液的流变特性研究%Rheological properties of aircraft deicing/anti-icing fluid

    Institute of Scientific and Technical Information of China (English)

    张亚博; 赵芯; 于新华; 张帆; 陈元

    2015-01-01

    The non-Newton aircraft deicing/anti-icing fIuid rheoIogicaI property through use of BrookfieId viscometer. By means of the aircraft deicing/anti-icing fIuid shear rate and shear stress measurement and data caIcuIation,found that under the condition of medium shear rate,the aircraft deicing/anti-icing fIuid conforms to the power Iaw. The shear rates tend to be zero and tend to infinity,the aircraft deicing/anti-ic-ing fIuid viscosity is cIose to a constant vaIue. The new rheoIogicaI equation can describe the rheoIogicaI properties of the aircraft deicing/anti-icing fIuid within the fuII scope of the shear rate.%使用BrookfieId粘度计对非牛顿流体型飞机除冰/防冰液的流变性进行了研究,通过对飞机除冰/防冰液剪切速率和剪切应力的测量和数据拟合,发现在中等剪切速率条件下,飞机除冰/防冰液符合幂律流体的流变特性;在剪切率趋近于0和趋近于无穷大时,飞机除冰/防冰液的粘度都是趋近于一个固定值,据此推导出新的流变方程,新流变方程能在整个剪切速率范围内很好的反应飞机除冰/防冰液的流变特性。

  7. Research Progress on Anti-icing Performance of Superhydrophobic Surfaces%超疏水表面抗结冰性能研究进展

    Institute of Scientific and Technical Information of China (English)

    冯杰; 卢津强; 秦兆倩

    2012-01-01

    阐述了近期国内外对超疏水表面抗结冰的研究进展,以期弄清这种特殊浸润性表面的抗结冰性能。发现必须根据超疏水表面的微结构类型判断其能否抗结冰,而不能只依据接触角进行笼统的判断。有些超疏水表面,其抗结冰能力随着结冰一融冰循环次数的增加而下降。在低温高湿条件下,很多超疏水表面的抗结冰能力会因水蒸气在表面微纳结构的间隙内冷凝而恶化。因此,设计机械强度高的超疏水表面(耐结冰一融冰循环)、或能使冷凝水滴在其上自迁移的新型超疏水表面、或者简单地在固体表面沉积一层光滑牢固的疏冰涂层,或许是制备持久抗结冰表面的现实、可靠选择。%The studies of ice accretion on superhydrophobic surfaces (SHS) in recent years were reviewed in this paper. The conclusion is that the detailed surface structure is very important in deciding whether SHS are really icephobic and judgment by contact angle alone is not sufficient. The ice-repellent properties of some SHS can deteriorate after icing/deicing cycles. The anti-icing efficiency of SHS can significantly lower in a humid atmosphere because water vapour condenses in the interspace between surface protrudes. Thus designing SHS with strong microstructure, or on which condensed water droplets could spontaneously move away, or simply depositing smooth coat with low ice adhesion strength, may be realistic and reliable selects in preparing anti-icing surfaces with long durability.

  8. Brief survey of deicing/anti-icing fluid and techniques for aircraft%飞机除冰/防冰液及除冰技术

    Institute of Scientific and Technical Information of China (English)

    李斌

    2012-01-01

    本文主要介绍了飞机除冰/防冰液的四种类型及主要技术要求,包括材料组成与理化性能、稳定性、使用性能、对飞机材料及机场跑道材料的影响、对生态环境的影响等,并简述了飞机液体防冰技术、机械除冰技术和热力防冰技术等几大类除冰技术的发展情况。%The four types and chief requirements of deicing/anti-icing fluid for aircraft were intrduced,including fluid composition and physical properties,stability,performance properties,effect on aircraft materials and runway concrete scaling resistance,environmental information,etc.The development of deicing techniques for aircraft which include fluid deicing,mechanical deicing and hot deicing were summarized.

  9. Research on Anodic Oxidation Preparation and Performance of Anti-icing Defrosting Coating%防冰除霜涂层的阳极氧化法制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    陈志; 闫共芹; 林瑞基; 闫斌; 刘建华

    2015-01-01

    输电线路覆冰使得电线出现一系列抖动、闪烁、烧伤现象,严重威胁着电力系统的安全运行,在输电线表面涂覆防冰除霜涂层制备防结冰除霜输电线是一种新的除冰防霜方法。为了探究防冰除霜涂层对输电线防冰除霜效果的影响,本文通过阳极氧化法制备出防冰除霜涂层输电线,并分别对不同材质的铝片进行实验研究。根据人工气候室中的实验结果,分析得出防冰除霜涂层对不同基底的输电线防冰都起到一定程度的作用,其中6061型号铝片延长结冰时间效果最好。%Transmission lines ice makes wire appearing a series of jitter, flicker, burned phenomenon. In transmission line surface coating anti-icing defrosting coating is a new method of deicing frost prevention.In order to explore the anti-icing defrosting coating on transmission line anti-icing defrosting effect, two different anti-icing defrosting coating were prepared by anode oxidation method on different aluminium materials. According to the experimental results of artificial climate chamber, two different deicing defrosting coating had inhibition to a certain degree in ice on power lines.Among them 6061 type aluminum prolonged freezing effect was best.

  10. Preparation and Anti-icing Properties of Superhydrophobic Coating%超疏水涂料的制备及其防覆冰性能

    Institute of Scientific and Technical Information of China (English)

    仇伟; 刘见祥; 曾舒; 张波; 冯利军

    2012-01-01

    基于室温硫化硅橡胶(RTV)技术,以端羟基聚硅氧烷(107硅橡胶)为成膜树脂,添加纳米二氧化硅粒子,在室温下制备出超疏水涂层,对其表面形貌和疏水性进行了表征和分析.结果表明,涂层表面具有类似荷叶的微米-纳米双重结构,其水滴静态接触角可达165°,滚动角仅为3.8°.通过覆冰试验发现,超疏水涂层在初期阶段降低了覆冰的增长速率,具有明显的防覆冰效果.%Based on the technique of RTV, the superhydrophobic coating was prepared at room temperature by using hydroxyl-terminated polydimethylsiloxane as the film-forming resin which combined nanometer silicon dioxide with different size. The morphology of coating surface was characterized and the hydrophobic performance was analyzed. The results indicate that there is a micro-nano binary structure similar lotus leaves on coating surface, which can make the highest static state contact angle of 165° and the lowest slide angle of 3. 8° between coating surface and water droplet. It is found via icing test that the super-dydrophobic coating made via this method has obvious anti-icing effect due to it can delay the growth rate of icing process during the early period.

  11. 基于PMRM的电网防冰雪灾害最优策略研究%Optimal Strategy of Anti-icing Disaster of Grid Based on PMRM

    Institute of Scientific and Technical Information of China (English)

    丁士; 王致杰; 李晨; 刘超; 曾鸣

    2013-01-01

    针对冰雪灾害造成的损失与其发生概率的相关性,采用分割多目标风险法(PMRM)将风险函数引入风险决策模型的目标函数中进行风险决策,并对不同地区防冰灾害策略进行了研究.实例应用表明,该方法合理有效,克服了传统方法的缺陷,为防冰灾策略提供了科学依据.%The loss caused by icing disaster is related to icing disaster's occurrence probability. This paper introduces risk function into objective function of risk decision-making model by using partitioned multi-objective risk method (PMRM). And then it studies anti-icing disaster strategy of different regions. Example results show that this method is reasonable and effective and it overcomes the shortcomings of traditional methods, which provides scientific basis for anti-icing strategy.

  12. Influence of free stream velocity on runback water flow and heat transfer on anti-icing surface%来流速度对防冰表面溢流水流动换热的影响

    Institute of Scientific and Technical Information of China (English)

    郑梅; 董威; 朱剑鋆; 郭之强

    2016-01-01

    为研究来流速度对防冰表面溢流水流动形态及换热的影响,基于空气-水两层相互作用的质量、动量和能量守恒,建立防冰表面溢流水水膜流动换热及破裂的数学模型,分析了防冰表面溢流水在不同来流条件下的流动形态和表面换热情况.计算分析表明:来流速度增加时,防冰表面相同位置处的连续水膜厚度减小,水膜破裂位置随之延后;较高来流速度条件下,破裂处水膜厚度稍有增加,使得破裂后形成的溪流厚度和宽度增大;作为主要的表面散热项,连续水膜表面蒸发及对流换热热流均随来流速度的增加而增大.此外,由水膜破裂引起的表面溢流水流态变化对防冰表面蒸发热流有一定影响.%The purpose of this paper is to investigate the effect of free stream velocity on the runback water flow and heat transfer on the anti-icing surface.Based on the mass,momentum and energy conservations of the runback water flow and the air flow,a mathematical model of the runback water film flow and rivulet flow was developed to investigate the effect of the free stream velocity on the heat and mass transfer on the anti-icing surface. The computation analysis indicates that the water film thickness at the same position on the anti-icing surface decreases with the free stream velocity increasing,and the rivulet thickness and width at the breakup point increase due to larger water film thickness at higher free stream velocity.Meanwhile,as the main heat losses on the anti-icing surface,the evaporation heat flux and the convection heat flux on the water film surface increase with the free stream velocity increasing. In addition, the characteristics of the heat and mass transfer on the dry surface,the fully wet surface and the partially wet surface were also investigated.The results show that the patterns of the runback water have some influence on the heat and mass transfer on the anti-icing surface.

  13. Analysis on Critical Anti-icing Current of Conductor and Its Impacting Factors%导线临界防冰电流及其影响因素分析

    Institute of Scientific and Technical Information of China (English)

    蒋兴良; 兰强; 毕茂强

    2012-01-01

    Conductor icing is one of major factors which affect the safe operation of the transmission line, and the anti-icing method based on the Joule heating effect is feasible and effective. Taking the skin effect, the effect of geometric shapes, and water film covering conductors on heat transfer process into consideration, we established a mathematical model of critical anti-icing current on the basis of Joule heating effect and the heat transfer process of conductor under critical icing condition, and its calculations were consistent with the test results in artificial climate chamber. The proposed model is more accurate compared with other current models. We also studied the effects of the geometrical parameters of conductor, environment temperature, wind velocity, liquid water content (LWC), and median volume diameter(MVD) on critical anti-icing current of conductor. The simulation results show that the critical current increases rapidly with decreasing temperature, and increases rapidly with increasing wind velocity. The critical current slowly increases with increasing LWC, and increases slowly with increasing MVD when MVD is in the range of 0-100 μm.%导线覆冰是影响输电线路安全运行的主要问题之一,基于焦耳热效应的临界电流防冰方法可行且有效。为此,基于焦耳热效应和导线在临界覆冰状态下的传热过程,并考虑了集肤效应、导线几何外形及其表面水膜对传热过程的影响,建立了临界防冰电流模型,其计算结果与人工气候室试验结果符合。另外,还研究了在覆冰环境下,导线直径及几何外形、环境温度、风速、液态水含量(LWC)、中值体积直径(MVD)对输电线路临界防冰电流的影响。仿真结果表明,临界防冰电流随温度的降低或风速的增加而迅速增大,随LWC的增大或MVD在0~100μm区间增大而缓慢增大,而当MVD〉100μm时,临界防冰电流无明显变化。

  14. Research of Wing Anti-ice System Performance Validation for Civil Aircraft%某型飞机机翼防冰系统性能验证研究

    Institute of Scientific and Technical Information of China (English)

    霍西恒; 王大伟; 李革萍; 李志茂

    2013-01-01

    A certain type of civil aircraft wing anti-ice system performance validation was introduced briefly first:the 2. 5D test model to verify the performance of three dimensional wing anti-ice system. A typical test condition selected to carry out the calculation of 2. 5D model and 3D model performance, meantime the icing wind tunnel test result of 2. 5D model for same condition was analyzed. At last, the 2. 5D model calculation results with the experi-mental results were compared and analyzed, and fixed the calculation results of 3D model,so as to achieve the pur-pose to verify the ice protection system performance.%介绍了某型支线客机机翼防冰系统的性能验证思路,即通过采用2.5D试验模型验证三维防冰系统的性能。选取一个典型状态点分别进行了2.5D及三维模型的性能计算分析,同时进行了相同状态点时2.5D模型的冰风洞试验结果分析,最后将2.5D模型计算结果与试验结果进行对比分析,修正3D模型的计算结果,从而达到验证整个防冰系统性能的目的。

  15. Conductor rail anti-icing sche me of monorail transit based on the Joule heat%基于焦耳热分析的单轨交通导电轨防覆冰方案

    Institute of Scientific and Technical Information of China (English)

    高晓杰; 郭蕾; 王旭光; 李群湛

    2014-01-01

    According to the characteristics of the urban monorail transit system,a melting ice plan of large current was proposed in this paper.Based on the joule heating effect,the heat balance equation of T-shaped special conductive rail in monorail transit system was established.Then the critical anti -icing current was calculated and the impact of environmental factors,such as temperature,wind speed,on the anti-icing current was inves-tigated.In order to validate its feasibility,T-shaped conductor rail model was generated in ANSYS and the thermal analysis was carried out.The results show that the critical melting current obtained in this study can meet the practical needs.%针对跨座式单轨交通系统的特点,提出一种大电流防融冰方案。基于焦耳热效应建立了单轨交通系统的T型专用导电轨的热平衡方程,计算其临界防冰电流,并分析温度、风速等环境因素对防冰电流的影响。为验证其可行性,在ANSYS中建立T型导电轨模型并对其进行热分析,结果显示计算得到的临界防冰电流满足实际所需。

  16. Design and Implementation of Anti-icing and Deicing System Based on Profibus for Icing Wind Tunnel%基于Profibus的结冰风洞防除冰系统设计与实现

    Institute of Scientific and Technical Information of China (English)

    刘小安; 张艳清; 杨洪涛

    2015-01-01

    Since the nodes of anti-icing and deicing system are disperse ,and there are many control tunnels and temperature sensors in anti-icing and deicing system ,this paper proposes a distributed system based on Profibus .The solutions to multiple control tunnels , multiple human-machine intefaces ,and bus real-time diagnosis are put forward .The practical results show that the system works w ell .%为了解决某结冰风洞防除冰系统分布较分散、各点之间距离较远、防除冰控制通道和温度采集点较多等问题 ,提出了基于Profibus的分布式控制系统 ,采用动力集中控制、测量数据分布式采集方案 ,综合了集中式控制和总线分布式控制的优点.采用面向对象的编程理念 ,通过模块化设计解决了多控制通道问题 ;通过特殊的工作模式控制策略 ,解决了多人机界面的问题 ;通过引入总线诊断功能 ,解决了复杂系统故障实时检测与快速定位问题.实际运行结果表明 ,基于Profibus的结冰风洞防除冰系统运行平稳 ,收到了预期效果.

  17. 快速喷雾结冰技术在循环冷却水塔中的应用%Application of Rapid Spray-Freezing Technology in the Anti-icing of Circulating Cooling Towers

    Institute of Scientific and Technical Information of China (English)

    郭民臣; 马英; 梅勇; 陈文飞; 王卜平

    2012-01-01

    针对我国北方地区发电厂中冷却水塔冬季防冻问题,提出了循环冷却水塔快速喷雾结冰技术.通过与悬挂挡风板冷却塔的对比,论证了快速啧雾结冰技术在优化调节循环水温度及循环冷却水塔防寒防冻方面的明显优势.结果表明:采用快速喷雾结冰技术能够使冷却水塔在严寒季节或天气情况突变时安全运行,可以使机组循环水温度随着环境温度高低和机组负荷大小而自动调整,以达到最佳值,从而提高了机组的经济性.%To realize the anti-icing purpose for power plant cooling towers in northern China, a rapid spray- freezing technology is proposed. By comparing the cooling tower adopting the rapid spray-freezing technol- ogy with that protected by suspension windshields, the former one is found to be more superior to the lat- ter one in the adjustment of circulating water temperature and in the anti-icing protection of cooling tower. Results show that with the rapid spray-freezing technology, the circulating water temperature may be ad- justed automatically to optimal data according to the variation of both the environmental temperature and the unit load, which therefore makes it possible for the unit to safely and economically operate during days of bitter cold or with sudden change in weather.

  18. 新型人工岛护坡抗冰结构的系统设计与应用%The system design and implementation of new manmade island revetment and anti-ice structure

    Institute of Scientific and Technical Information of China (English)

    刘喜传

    2012-01-01

    In Bohai Bay, temperature is low and icing period is long in the winter, so that the large ice blocks impact slope of the man-made island due to environmental driving load and endanger oilfield engineering and personal safety, while the exist-ing revetment structure is so difficult to meet this demand under the extra environmental condition. Therefore, a new man-made island revetment and anti-ice structure, namely umbrella block, is put foreword and the technical parameters of the new kind of revetment block are determined for the different water depths. Model test installation and field application results have shown that the new type of anti-ice structure can resist the large ice impact effectively, give economic efficiency obviously and have very good promotion value, compared with the existing man-made island revetment structure.%渤海湾冬季温度低,海冰结冰期长,大型冰块在环境驱动力的驱动下冲击人工岛护坡,危及油田工程和人身的安全,而现有的护坡结构形式很难满足特殊海况的要求,因此提出了一种新型人工岛护坡抗冰结构——伞型块体,并确定了这种新型护坡块体在不同水深下的技术使用参数.模型试验安装与现场应用结果表明,与现有的人工岛护坡结构相比,这种新型抗冰结构形式能够很好地抵抗大型冰块的冲击,经济性显著,具有很好的推广价值.

  19. 三维内外热耦合计算热气防冰系统表面温度%Three-dimensional conjugate heat transfer simulation for the surface temperature of wing hot-air anti-icing system

    Institute of Scientific and Technical Information of China (English)

    卜雪琴; 林贵平; 郁嘉

    2009-01-01

    提出了一种三维内外强固传热耦合计算热气防冰系统表面温度的方法并进行算例计算.外部表面传热系数计算采用附面层积分方法,内部热气流动与换热采用CFD(计算流体动力学)方法,利用FLU-ENT的用户自定义甬数UDFs(user~defined functions)实现蒙皮外表面热载荷计算及热流边界条件的自动加载,使迭代自动推进.对表面温度及外部热载倚进行亚松弛来稳定迭代计算,用强固传热耦合迭代来加快计算速度.所研究的三维热气防冰系统表面温度计算新方法可应用于防冰系统的热性能验证及系统优化.%The conjugate heat transfer of a 3-D wing hot-air anti-icing system was studied and a method for calculation of the surface temperature was presented in this paper. The method employed the commercial software package FLUENT and its user-defined functions (UDFs) to integrate tightly the external heat flux, internal heat flux and the thermal conduction in the skin. The external convective heat transfer coefficient was computed using the boundary layer integrated method, and the internal hot air flow and heat transfer was modeled using FLUENT. The iteration for the sequential coupling of internal, external and conductive heat transfer was implemented by automatically calculating the external heat flux and setting the heat flux boundary condition on the external surface with UDFs. This new method for a wing anti-icing system can be applied to verification of its feasibility and validity.

  20. Experimental study of anti-icing coatings' use on wind turbine blades; Etudes experimentale de l'utilisation de revetements a caractere glaciophobe sur les pales d'eolienne

    Energy Technology Data Exchange (ETDEWEB)

    Adomou, M.; Fortin, G.; Perron, J. [Quebec Univ., Chicoutimi, PQ (Canada). Anti-Icing Materials International Laboratory

    2010-07-01

    Ice accumulation on wind turbine blades can result in energy production losses, mechanical overloads, and ice shedding. The de-icing systems which are currently used are energy intensive. This poster reported on a study that investigated the use of ice-phobic coatings as a means of protecting wind turbines during cold weather. The study examined the behaviour of various coatings on wind turbine blades under icing conditions and investigated the feasibility of reducing the surface temperature of heated blades with the addition of ice-phobic or hydrophobic coatings. The performance of the thermal systems combined with the coatings was also investigated. The coatings included a polyurethane plastic film; a silicone-epoxy composite; a fluorinated resin; and a fluoroethane compound. The coatings were applied to a NACA airfoil placed in an icing wind tunnel. Various ice accumulation regimes, wind speeds, and temperatures were studied. The coatings proved to be effective against run-back effects during anti-icing operations, and may increase production. tabs., figs.

  1. 输电线路绝缘子湿增长覆冰特性及防冰涂料试验研究%Characteristics of Wet Growth Icing and Eperimental Investigation of Anti-icing Material of Transmission Line Insulators

    Institute of Scientific and Technical Information of China (English)

    许志海; 贾志东; 关志成; 李智宁; 韦晓星; 王黎明

    2011-01-01

    Ice accumulation on insulators and transmission lines imposes serious problems on power systems, and se rious incidents happen occasionally due to the lack of effective countermeasures. We introduced the recently progress of the work by Laboratory of Advanced Technology of Electrical Engineering &. Energy at Tsinghua University on the artificial icing test methods and anti-icing material for insulators. Unlike the commonly used icing methods which focused on making the ice weight and shape similar to the natural icing, we proposed a methods to make the icing speed as close as the wet-growth in natural conditions by choosing the size of the water droplets and the ambient temperature. A semiconducting coating was investigated, and the surface heating effect and anti-icing performance were tested. The anti-icing performances of these RTV silicone rubber coatings on short insulators strings of three pieces insulators with different leakage current magnitudes were compared in a climate chamber, and the sufficient leakage current for anti-icing was derived from the experiments. The results show that the surface heating effect, together with the hydrophobicity, can significantly reduce the formation of ice on insulators.%输电线路覆冰问题威胁着电力系统的安全运行.由于缺乏有效的防覆冰手段,覆冰事故时有发生.鉴于此,介绍了清华大学在人工覆冰试验方法的自然等效性和绝缘子防覆冰涂料方面的相关研究工作.现有人工气候室试验方法和相关标准主要采用覆冰厚度和形态等参数去模拟自然覆冰形态,该研究则采用从覆冰速度上模拟自然覆冰环境的方法,通过选择覆冰水滴大小和环境温度的配合,模拟危害较大的湿增长覆冰过程,并使覆冰速度接近自然覆冰环境.防覆冰涂料研究方面,采用一种结合了憎水性和表面发热特性的半导电材料,通过试验验证了憎水性叠加发热性的表面对覆冰过程的

  2. Picosecond laser machined designed patterns with anti-ice effect

    NARCIS (Netherlands)

    Arnaldo del Cerro, Daniel; Römer, G.R.B.E.; Huis in 't Veld, A.J.

    2010-01-01

    Micromachining using ultra short laser pulses (USLP) has evolved over the past years as a versatile tool for introducing functional features in surfaces at a micrometric and even at a sub wavelength scale. Being able to control the surface topography at this level provides a method to change the wet

  3. UAV anti-icing system based on conductive coating

    OpenAIRE

    Helland, Andreas Strand

    2014-01-01

    Icing on leading edge surfaces such as wings and propeller blades presents a major risk for UAVs operating in a cold and humid environment. Reducing or loss of manoeuvrability, loss of lift, increase in drag, reducing performance through increased weight and in worst case crashing, are phenomena that can occur in case of ice formation on a UAV surface. The use of UAVs has increased significantly the last years through surveillance and reconnaissance operations and they are able to perform ope...

  4. State of the art and practice of pavement anti-icing and de-icing techniques

    Institute of Scientific and Technical Information of China (English)

    WenBing Yu; Xin Yi; Ming Guo; Lin Chen

    2014-01-01

    Pavement snow and icing are worldwide problems, but effective countermeasures are just beginning to be developed in China. The two most common snow and ice removal methods are mechanical clearance and chemical melting, and the advantages and disadvantages of each approach are discussed here, including environmental and structural damage caused by corrosive snow melting agents. New developments in chemical melting agents and mechanical equipment are discussed, and an overview of alternative thermal melting systems is presented, including the use of geothermy and non-geothermal heating systems utilizing solar energy, electricity, conductive pavement materials, and infrared/microwave applications. Strategic recommendations are made for continued enhancement of public safety in snow and ice conditions.

  5. New Ionic Liquids from Natural Products for Environmentally Benign Aircraft Deicing and Anti-Icing

    Science.gov (United States)

    2010-12-10

    effective concentration to immobilize 50% microorganism GRAS ‘generally regarded as safe’, Food & Drug Administration ILs ionic liquids J·mol-1·K...mixture of propylene glycol/water just before takeoff. Although propylene glycol is ‘generally regarded as safe’ (GRAS) by the US Food & Drug ...Commun. 2004, 630-631. St. Kalb, R.; Kotschan, M. J. Ionic liquids based on dibutylphosphate; chiral and “natural” ionic liquids. proionic

  6. Ultra short pulse laser generated surface textures for anti-ice applications in aviation

    NARCIS (Netherlands)

    Römer, G.W.; Del Cerro, D.A.; Sipkema, R.C.J.; Groenendijk, M.N.W.; Huis in 't Veld, A.J.

    2009-01-01

    By laser ablation with ultra short laser pulses in the pico- and femto-second range, well controlled dual scaled micro- and nano-scaled surface textures can be obtained. The micro-scale of the texture is mainly determined by the dimensions of the laser spot, whereas the superimposed nano-structure i

  7. Formulations for aircraft and airfield deicing and anti-icing: aquatic toxicity and biochemical oxygen demand

    Science.gov (United States)

    Ferguson, Lee; Corsi, Steven R.; Geis, Steven W.; Anderson, Graham; Joback, Kevin; Gold, Harris; Mericas, Dean; Cancilla, Devon A.

    2008-01-01

    The Airport Cooperative Research Program (ACRP) has sponsored research on environmental characteristics of aircraft and pavement deicers and anti-icers focusing primarily on biochemical oxygen demand (BOD) and aquatic toxicity of formulated products and individual chemical components of formulations. This report presents a background of issues leading to this research, objectives of this document, and a description of the efforts and findings of this research.

  8. Evaluation of the Improved OV-1D Anti-Icing System

    Science.gov (United States)

    1988-04-01

    detector unit, Cloud Technology Inc., model LWH-1 (Johnson Williams type) LWC indicator system, Small Intelligent Icing Data System (SIDS), and two visual...9. The Cloud Technology ice detector has a calibrated resistance wire %khich is mounted in the airstream and connected as one branch of a balanced

  9. Evaluation of the Improved OV-ID Anti-Icing System. Phase 2

    Science.gov (United States)

    1989-04-01

    mirror dew point hygrometer and display, Cloud Technology Inc. model LWH-1 (Johnson Williams type) liquid water content (LWC) indicator system, Small...gm/m 3) h. median volumetric diameter (±im) i. amount of LWC observed for each channel (TOTAL 30) of both probes (gm’m 3 ) 7. The Cloud Technology ice

  10. Erosion resistant anti-ice surfaces generated by ultra short laser pulses

    NARCIS (Netherlands)

    Del Cerro, D.A.; Römer, G.R.B.E.; Huis in't Veld, A.J.

    2010-01-01

    Wetting properties of a wide range of materials can be modified by accurate laser micromachining with ultra short laser pulses. Controlling the surface topography in a micro and sub-micrometer scale allows the generation of water-repellent surfaces, which remain dry and prevent ice accumulation unde

  11. Environmentally Benign Aircraft Anti-icing and Deicing Fluids Based on Cost Effective, Bio-based Ingredients

    Science.gov (United States)

    2012-09-01

    Examination of Water and Waste Water 2.5 OECD Publications Available from OECD: 2, rue André Pascal, Cedex 16, 75016 Paris, FRANCE or oecd.or. OECD Guidelines...Water and Waste Water". The manufacturer shall provide results for not less than the following: 3.1.4.1 Biochemical Oxygen Demand (BOD) The fluid...an initial surface temperature of 22 °C ± 2 (72 "F ± 4), the fluid shall not produce any streaking, discoloration, or blistering of the paint film

  12. Carbon Nanomaterial-Based Wing Temperature Control System for In-Flight Anti-Icing and De-Icing of Unmanned Aerial Vehicles

    OpenAIRE

    Sørensen, Kim Lynge; Strand Helland, Andreas; Johansen, Tor Arne

    2015-01-01

    Structural changes due to ice accretion are common causes for unmanned aerial vehicle incidents in Arctic regions. For fixed wing unmanned aerial vehicles (UAVs) the leading edge of airfoil surfaces is one of the primary surfaces exposed to these changes, causing a significant reduction in aerodynamic ability, i.e. decreasing lift and manoeuvrability, and increasing drag, weight, and consequently power consumption. Managing or altogether preventing ice accretion could potentially prevent icin...

  13. Measures to reduce the impact of anti-icing agents on the environment and on the work of wastewater treatment facilities

    Directory of Open Access Journals (Sweden)

    Voronov Yuriy Viktorovich

    2014-09-01

    Full Text Available This article analyses the impact of the excess of chemical agents in the snow on the environment and on the working waste water treatment facilities. The article presents some suggestions for improvement of regulatory requirements concerning design engineering of snow melting facilities in the water disposal system. This suggestion was substantiated to assess snow as waste disposed from road surface, and to register snow mass delivered to snow melting facilities in equivalent units. It is assumed that snow melting stations are facilities designed for waste treatment, and this is why the project documentation for construction of these facilities has to undergo a state expertise for Environmental Impact Assessment. Completed studies provide estimates of the receipted snow, its pollution, etc. But at the same time these studies serve as the basis for approving the necessity of developing a unified system for monitoring the city's snow-melting plants to ensure the reliability.

  14. The Analysis and Study for Wing Anti-Ice System of Two Type Aircrafts%两种机型机翼防冰系统的分析研究

    Institute of Scientific and Technical Information of China (English)

    周景锋; 李秦岭

    2010-01-01

    介绍了支线客机安140-100飞机和ARJ21-700飞机(以下简称A飞机和B飞机)的机翼防冰系统,主要包括机翼防冰系统的工作原理、组成和安装、技术参数等方面,并对两种飞机的机翼防冰系统进行了全面的比较分析,进而为我国飞机机翼防冰系统的设计和研制提供参考.

  15. 飞秒激光制备超疏水铜表面及其抗结冰性能%Femtosecond Laser Fabricated Superhydrophobic Copper Surfaces and Their Anti-Icing Properties

    Institute of Scientific and Technical Information of China (English)

    龙江游; 吴颖超; 龚鼎为; 范培迅; 江大发; 张红军; 钟敏霖

    2015-01-01

    超疏水表面的制备及其抗结冰性能受到广泛关注,但超疏水表面的微观结构及浸润性能对其抗结冰性能的影响规律仍无定论.利用飞秒激光在金属铜表面制备了一系列具有不同微观特征的微纳米结构,这些表面经过化学修饰后都具有超疏水性,同时对水具有不同的粘附性.系统研究了这些超疏水表面的抗结冰性能,结果表明,这些超疏水表面在低温(-5℃,-10℃)下都能延缓表面水滴的结冰过程.超疏水表面对水的粘附性对其抗结冰性能有显著影响,粘附性较小的超疏水表面比高粘附的超疏水表面具有更为优异的抗结冰性能.

  16. 76 FR 18024 - Airworthiness Directives; Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440...

    Science.gov (United States)

    2011-04-01

    ...., Washington, DC. FOR FURTHER INFORMATION CONTACT: Wing Chan, Aerospace Engineer, Avionics and Flight Test... states: At present, the Wing Anti-Ice System (WAIS) sufficient heat switches/sensors on CL-600-2B19..., certain WAIS mode selection changes may result in a two-minute inhibition of the wing anti-ice message,...

  17. 77 FR 67263 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2012-11-09

    ...-Royce Trent engines, worn and detached attachment ] links, and fractured thermal anti-ice (TAI) piccolo..., Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington... worn, and some had become detached. In 2 cases, the Thermal Anti Ice (TAI) Piccolo tube was...

  18. HybridSil Icephobic Nanocomposites for Next Generation Aircraft In-Flight Icing Measurement and Mitigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this Phase I SBIR program is to adapt NanoSonic's HybridSil™ nanocomposites that combine high levels of erosion resistance and anti-icing...

  19. HybridSil Icephobic Nanocomposites for Next Generation Aircraft In-Flight Icing Measurement and Mitigation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this SBIR program is to adapt NanoSonic's HybridSil® nanocomposites and combine high erosion resistance, low ice adhesion, and passive anti-icing...

  20. Effect of wettability and surface roughness on ice-adhesion strength of hydrophilic, hydrophobic and superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Bharathidasan, T. [Surface Engineering Division, CSIR- National Aerospace Laboratories, Bangalore 560017 (India); Kumar, S. Vijay; Bobji, M.S. [Department of Mechanical Engineering, Indian Institute of Science, Bangalore 560003 (India); Chakradhar, R.P.S. [Surface Engineering Division, CSIR- National Aerospace Laboratories, Bangalore 560017 (India); Basu, Bharathibai J., E-mail: bharathijbasu@gmail.com [Surface Engineering Division, CSIR- National Aerospace Laboratories, Bangalore 560017 (India)

    2014-09-30

    Highlights: • Anti-icing property is related to wettability and surface roughness. • Silicone based hydrophobic coating showed excellent ice-adhesion strength. • Superhydrophobic surfaces displayed poor anti-icing property. - Abstract: The anti-icing properties of hydrophilic, hydrophobic and superhydrophobic surfaces/coatings were evaluated using a custom-built apparatus based on zero-degree cone test method. The ice-adhesion reduction factor (ARF) of these coatings has been evaluated using bare aluminium alloy as a reference. The wettability of the surfaces was evaluated by measuring water contact angle (WCA) and sliding angle. It was found that the ice-adhesion strength (τ) on silicone based hydrophobic surfaces was ∼ 43 times lower than compared to bare polished aluminium alloy indicating excellent anti-icing property of these coatings. Superhydrophobic coatings displayed poor anti-icing property in spite of their high water repellence. Field Emission Scanning Electron Microscope reveal that Silicone based hydrophobic coatings exhibited smooth surface whereas the superhydrophobic coatings had a rough surface consisting of microscale bumps and protrusions superimposed with nanospheres. Both surface roughness and surface energy play a major role on the ice-adhesion strength of the coatings. The 3D surface roughness profiles of the coatings also indicated the same trend of roughness. An attempt is made to correlate the observed ice-adhesion strength of different surfaces with their wettability and surface roughness.

  1. The commercial development of water repellent coatings for high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Scott Robert [ORNL

    2013-10-01

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  2. The commercial development of water repellent coatings for high voltage transmission lines

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, S. R. [ORNL; Daniel, A. [Southwire Company

    2013-10-31

    The purpose of the Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC and Southwire Company was to jointly develop a low cost, commercially viable, water-repellant anti-icing coating system for high voltage transmission lines. Icing of power lines and other structures caused by freezing rain events occurs annually in the United States, and leads to severe and prolonged power outages. These outages cause untold economic and personal distress for many American families and businesses. Researchers at the Department of Energy?s Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee have previously developed a set of superhydrophobic coatings with remarkable anti-icing properties that could potentially be sprayed or painted onto high-tension power lines and pylons. These coatings drastically reduce ice accumulation on these structures during freezing rain events. The project involved obtaining technical input, supplies and test high voltage cables from Southwire, along with the joint development of anti-icing coating techniques, which would result in a commercial license agreement between Southwire and ORNL, and potentially other companies requiring water repellent anti-icing coatings.

  3. Aircraft and Pavement Deicer and Anti-Icer Forensics: Which Formulations Reach the Receiving Water and What are Their Potential Impacts

    Science.gov (United States)

    To characterize the effects from runoff of aircraft deicer and anti-icer fluid (ADAF) and pavement deicer formulations (PDF) on receiving water, multiple deicing and anti-icing formulations must be considered. ADAF formulations used on aircraft include Type I fluids (deicers) and Type IV fluids (an...

  4. Wettability-independent bouncing on flat surfaces mediated by thin air films

    NARCIS (Netherlands)

    Ruiter, de J.; Lagraauw, R.; Ende, van den H.T.M.; Mugele, F.

    2015-01-01

    The impingement of drops onto solid surfaces1, 2 plays a crucial role in a variety of processes, including inkjet printing, fog harvesting, anti-icing, dropwise condensation and spray coating3, 4, 5, 6. Recent efforts in understanding and controlling drop impact behaviour focused on superhydrophobic

  5. 75 FR 25788 - Airworthiness Directives; Bombardier, Inc. Model CL-600-2B19 (Regional Jet Series 100 & 440...

    Science.gov (United States)

    2010-05-10

    ... receipt. FOR FURTHER INFORMATION CONTACT: Wing Chan, Aerospace Engineer, Avionics and Flight Test Branch... unsafe condition for the specified products. The MCAI states: At present, the Wing Anti-Ice System (WAIS... activation of the low- heat detection switches, certain WAIS mode selection changes may result in a...

  6. 14 CFR Appendix C to Part 63 - Flight Engineer Training Course Requirements

    Science.gov (United States)

    2010-01-01

    ... systems. Pneumatic systems. Electrical systems. Anti-icing and de-icing systems. Pressurization and air... the students pass the FAA written test on the first attempt. (2) Approval of a flight course is discontinued whenever less than 80 percent of the students pass the FAA practical test on the first attempt....

  7. Glaze Icing on Superhydrophobic Coating Prepared by Nanoparticles Filling Combined with Etching Method for Insulators

    Directory of Open Access Journals (Sweden)

    Chao Guo

    2015-01-01

    Full Text Available Icing on insulators may cause flashover or even blackout accidents in the power transmission system. However, there are few anti-icing techniques for insulators which consume energy or manpower. Considering the water repelling property, the superhydrophobic surface is introduced for anti-icing of insulators. Among the icing forms, the glaze icing owns the highest density, strongest adhesion, and greatest risk to the power transmission system but lacks researches on superhydrophobic surface. In this paper, superhydrophobic surfaces with contact angle of 166.4°, contact angle hysteresis of 0.9°, and sliding angle of less than 1° are prepared by nanoparticle filling combined with etching method. The coated glass slide and glass insulator showed excellent anti-icing performance in the glaze icing test at −5°C. The superhydrophobicity and anti-icing property of the coatings benefit from the low surface energy and hierarchical rough structure containing micron scale pits and nanoscale coralloid bulges supported by scanning electron microscopy (SEM, atomic force microscopy (AFM, and X-ray photoelectron spectroscopy (XPS characterization.

  8. Agent-based scheduling for aircraft deicing

    NARCIS (Netherlands)

    Mao, X.; Ter Mors, A.W.; Roos, N.; Witteveen, C.

    2006-01-01

    The planning and scheduling of the deicing and anti-icing activities is an important and challenging part of airport departure planning. Deicing planning has to be done in a highly dynamic environment involving several autonomous and self-interested parties. Traditional centralized scheduling approa

  9. 77 FR 26998 - Airworthiness Directives; Airbus Airplanes

    Science.gov (United States)

    2012-05-08

    ...- Royce Trent engines, worn and detached attachment links, and fractured thermal anti-ice (TAI) piccolo tubes. This proposed AD would require inspecting piccolo tubes, piccolo tube mount links, the aft side... engine nose cowl and a broken piccolo tube, which could lead to in- flight damage of the engine...

  10. 78 FR 21578 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-04-11

    ... Company (GE) model GEnx-2B67 and GEnx-2B67B turbofan engines with booster anti-ice (BAI) air duct, part... reports of cracks in the BAI air duct. This proposed AD would require initial and repetitive visual inspections of the BAI air duct, removal from service of the BAI air duct if it fails inspection and, as...

  11. Nanoparticle and gelation stabilized functional composites of an ionic salt in a hydrophobic polymer matrix.

    Science.gov (United States)

    Kanyas, Selin; Aydın, Derya; Kizilel, Riza; Demirel, A Levent; Kizilel, Seda

    2014-01-01

    Polymer composites consisted of small hydrophilic pockets homogeneously dispersed in a hydrophobic polymer matrix are important in many applications where controlled release of the functional agent from the hydrophilic phase is needed. As an example, a release of biomolecules or drugs from therapeutic formulations or release of salt in anti-icing application can be mentioned. Here, we report a method for preparation of such a composite material consisted of small KCOOH salt pockets distributed in the styrene-butadiene-styrene (SBS) polymer matrix and demonstrate its effectiveness in anti-icing coatings. The mixtures of the aqueous KCOOH and SBS-cyclohexane solutions were firstly stabilized by adding silica nanoparticles to the emulsions and, even more, by gelation of the aqueous phase by agarose. The emulsions were observed in optical microscope to check its stability in time and characterized by rheological measurements. The dry composite materials were obtained via casting the emulsions onto the glass substrates and evaporations of the organic solvent. Composite polymer films were characterized by water contact angle (WCA) measurements. The release of KCOOH salt into water and the freezing delay experiments of water droplets on dry composite films demonstrated their anti-icing properties. It has been concluded that hydrophobic and thermoplastic SBS polymer allows incorporation of the hydrophilic pockets/phases through our technique that opens the possibility for controlled delivering of anti-icing agents from the composite.

  12. Nanoparticle and gelation stabilized functional composites of an ionic salt in a hydrophobic polymer matrix.

    Directory of Open Access Journals (Sweden)

    Selin Kanyas

    Full Text Available Polymer composites consisted of small hydrophilic pockets homogeneously dispersed in a hydrophobic polymer matrix are important in many applications where controlled release of the functional agent from the hydrophilic phase is needed. As an example, a release of biomolecules or drugs from therapeutic formulations or release of salt in anti-icing application can be mentioned. Here, we report a method for preparation of such a composite material consisted of small KCOOH salt pockets distributed in the styrene-butadiene-styrene (SBS polymer matrix and demonstrate its effectiveness in anti-icing coatings. The mixtures of the aqueous KCOOH and SBS-cyclohexane solutions were firstly stabilized by adding silica nanoparticles to the emulsions and, even more, by gelation of the aqueous phase by agarose. The emulsions were observed in optical microscope to check its stability in time and characterized by rheological measurements. The dry composite materials were obtained via casting the emulsions onto the glass substrates and evaporations of the organic solvent. Composite polymer films were characterized by water contact angle (WCA measurements. The release of KCOOH salt into water and the freezing delay experiments of water droplets on dry composite films demonstrated their anti-icing properties. It has been concluded that hydrophobic and thermoplastic SBS polymer allows incorporation of the hydrophilic pockets/phases through our technique that opens the possibility for controlled delivering of anti-icing agents from the composite.

  13. Etude experimentale de l'utilisation des revetements glaciophobes et/ou hydrophobes sur les pales d'eoliennes

    Science.gov (United States)

    Adomou, Maryelle C.

    2011-12-01

    Blade icing is a major problem of windmill use in northern climates. At present, the use of anti-icing protection on blades is little used because it is energy intensive and unsafe. An interesting current alternative is the use of ice-shedding coatings because they are proving to be less energy hungry, but their efficiency and durability have yet to be proven in windmills. Since windmills have a special dynamic structure and icing events can be of several types, an understanding of the accretion process on a variety of coatings is necessary to advance general knowledge in this field. To explore this problem, experiments were performed in the refrigerated wind tunnel at the Anti-icing Materials International Laboratory of the Universite du Quebec a Chicoutimi on a static-blade section covered with three commercial ice-shedding coatings chosen using well-defined criteria. Experimental conditions were based on several real extreme icing events. Scaling of the parameters of the icing events gave two air speeds for the wind tunnel (21 and 33m/s), two air temperatures (5 and -20°C) and one humidity level (0.4g/m 3). The experimental runs were carried out on blades covered with the coatings alone and also in combination with an electrothermal deicing system. The efficiency of the apparatus was evaluated by analysing the shape of the ice formed, the energy consumption of each anti-icing and de-icing combination and also by analysing the internal distribution of temperatures in the system. When used as a protective anti-icing system, none of the icephobic coatings was effective in reducing ice accumulation significantly on the blades. However, combined with an electrothermal anti-icing system, these types of coatings proved to be effective. Nevertheless, the power must be high enough to cause runoff. Hydrophobic coatings reduce energy consumption of electric anti-icing systems by about 7% whereas a super hydrophobic coating can reduce energy consumption by more than twice

  14. Temperature Distribution Measurement of The Wing Surface under Icing Conditions

    Science.gov (United States)

    Isokawa, Hiroshi; Miyazaki, Takeshi; Kimura, Shigeo; Sakaue, Hirotaka; Morita, Katsuaki; Japan Aerospace Exploration Agency Collaboration; Univ of Notre Dame Collaboration; Kanagawa Institute of Technology Collaboration; Univ of Electro-(UEC) Team, Comm

    2016-11-01

    De- or anti-icing system of an aircraft is necessary for a safe flight operation. Icing is a phenomenon which is caused by a collision of supercooled water frozen to an object. For the in-flight icing, it may cause a change in the wing cross section that causes stall, and in the worst case, the aircraft would fall. Therefore it is important to know the surface temperature of the wing for de- or anti-icing system. In aerospace field, temperature-sensitive paint (TSP) has been widely used for obtaining the surface temperature distribution on a testing article. The luminescent image from the TSP can be related to the temperature distribution. (TSP measurement system) In icing wind tunnel, we measured the surface temperature distribution of the wing model using the TSP measurement system. The effect of icing conditions on the TSP measurement system is discussed.

  15. Dynamic behavior of a vibrated droplet on a low-temperature micropillared surface

    Science.gov (United States)

    Tan, Chen-chuan; Jia, Zhi-hai; Yang, Hui-nan; Zhang, Zhi-tao

    2017-02-01

    The dynamic behavior of a vibrated droplet on a micropillared hydrophobic surface under low temperature was investigated in this paper. It was observed that solidified time of droplets on the micropillared surface were much larger than on the smooth surface due to the existence of wetting transition at low temperature, without vibration. The solidified time of droplets was longer while vibration was exerted on the surfaces, even though the wetting transition time of droplets at low temperature was shorter than at room temperature. It was found that resonance frequency of droplet increased as surface tension increased due to low temperature. Moreover, when a droplet was in its resonance frequency, the wetting area between the droplet and the micropillared surface increased obviously and its solidified time decreased substantially, and it led to the decline of anti-icing performance. This work is helpful to design a more efficient anti-icing device.

  16. 78 FR 50320 - Airworthiness Directives; General Electric Company Turbofan Engines

    Science.gov (United States)

    2013-08-19

    ...-2B67B turbofan engines with booster anti-ice (BAI) air duct, part number (P/N) 2469M32G01, and support bracket, P/N 2469M46G01, installed. This AD was prompted by reports of cracks in the BAI air duct. This AD requires initial and repetitive visual inspections of the BAI air duct, removal from service of the BAI...

  17. Microbiological Spoilage of Aviation Turbine Fuel: Part II Evaluation of a Suitable Biocide

    Directory of Open Access Journals (Sweden)

    H. M. Dayal

    1992-01-01

    Full Text Available Addition of ethylene glycol monoethyl ether, an anti-icing fuel additive supports microbial growth when added to aviation turbine fuel in low dosages. however, increases in its concentration to certain limits effectively prevents bioactivity in the fuel. The optimum dosage of this biocide for prevention of bioactivity in aviation turbine fuel has been studied by the specified qualitative performance tests after 18 months storage of the inhibited fuel under accelerated conditions of temperature and humidity.

  18. Microbiological Spoilage of Aviation Turbine Fuel: Part II Evaluation of a Suitable Biocide

    OpenAIRE

    1992-01-01

    Addition of ethylene glycol monoethyl ether, an anti-icing fuel additive supports microbial growth when added to aviation turbine fuel in low dosages. however, increases in its concentration to certain limits effectively prevents bioactivity in the fuel. The optimum dosage of this biocide for prevention of bioactivity in aviation turbine fuel has been studied by the specified qualitative performance tests after 18 months storage of the inhibited fuel under accelerated conditions of tem...

  19. Materials and Additive Manufacturing for Energy Efficiency in Wind Turbine and Aircraft Industries

    Energy Technology Data Exchange (ETDEWEB)

    Datskos, Panos G [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Polyzos, Georgios [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Clemons, Art [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bolton, Paul [Piedmont Propulsion Systems, LLC, Winston-Salem, NC (United States); Hollander, Aaron [First Aviation Services Inc., Westport, CT (United States)

    2016-05-04

    The purpose of this project was to develop surface treatments which will inhibit the formation of ice on turbine blades and propellers. ORNL worked with Piedmont Propulsion Systems, LLC and First Aviation Services Inc. to demonstrate a new surface treatment for two primary markets, aviation and wind turbines, as well as secondary markets such as power lines, bridges, boats, roofs and antennas among others. Exploring alternative surface treatments for wind turbines will provide anti-icing properties and erosion/abrasion prevention properties similar to those for aviation applications. A series of superhydrophobic coating materials was synthesized and successfully applied on anti-ice tape materials that could be used in a wide range of wind turbine and aviation applications to prevent ice accumulation. The coatings developed in this project were based on superhydrophobic particles of different geometries and sizes that were homogeneously dispersed in polymeric binders. The superhydrophobic features of the coatings are volumetric and their abrasion resistance was evaluated. Future research will involve the demonstration of anti-icing properties of the surface treatment developed in this project.

  20. Partnerships in winter maintenance that achieve environmental and cost saving benefits : nomination for the 2000 TAC Environmental Achievement Award

    Energy Technology Data Exchange (ETDEWEB)

    Gilfillan, G.B. [Insurance Corp. of British Columbia, North Vancouver, BC (Canada)

    2001-07-01

    Transportation agencies face the challenge of providing safe and efficient transportation systems while trying to maintain a balanced ecosystem. Long winters are an added challenge in Canada. The transportation industry has found an unlikely advocate in the field of auto insurance. The Insurance Corporation of British Columbia (ICBC) has taken the initiative to improve winter road maintenance practices that will have lasting positive effects on the environment and safety of the motoring public. Numerous agencies, associations, municipalities, businesses and individuals have expressed a commitment to initiatives such as the anti-icing/prewetting pilot project called the Winter Road Research project. The project includes the use of liquid magnesium chloride to prevent ice from forming a bond with the road surface. Pre-wetting was used with traditional solid winter maintenance materials. Salt or aggregate is pre-wet with the same anti-icing liquid just before they contact the roadway surface. The deicer enables the sand and salt granules to remain on the road surface for longer periods of time. Pre-wetting of salt with a liquid anti-icer reduces the amount of chemicals needed in winter maintenance operations while maintaining the same level of service. In addition, this program addresses the issue of heavy heavy metals which are an increasing environmental concern. The reduction in the amount of abrasives placed on the roads is beneficial to the environment in terms of reduced heavy metals to roadside vegetation, streams and city drains. The program was first launched in Kamloops, British Columbia but has now expanded throughout the province to include 43 municipalities. The ICBC has provided more than $3 million for the purchase of 125 anti-icing vehicles and 1100 prewet kits. The program has resulted in significant cost savings and a reduction in weather related accidents. 5 refs., 3 figs.

  1. Temperature dependent droplet impact dynamics on flat and textured surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Azar Alizadeh; Vaibhav Bahadur; Sheng Zhong; Wen Shang; Ri Li; James Ruud; Masako Yamada; Liehi Ge; Ali Dhinojwala; Manohar S Sohal (047160)

    2012-03-01

    Droplet impact dynamics determines the performance of surfaces used in many applications such as anti-icing, condensation, boiling and heat transfer. We study impact dynamics of water droplets on surfaces with chemistry/texture ranging from hydrophilic to superhydrophobic and across a temperature range spanning below freezing to near boiling conditions. Droplet retraction shows very strong temperature dependence especially for hydrophilic surfaces; it is seen that lower substrate temperatures lead to lesser retraction. Physics-based analyses show that the increased viscosity associated with lower temperatures can explain the decreased retraction. The present findings serve to guide further studies of dynamic fluid-structure interaction at various temperatures.

  2. Energy-Efficient Systems Eliminate Icing Danger for UAVs

    Science.gov (United States)

    2010-01-01

    Ames Research Center engineer Leonard Haslim invented an anti-icing t echnology called an electroexpulsive separation system, which uses m echanical force to shatter potentially dangerous ice buildup on an ai rcraft surface. Temecula, California-based Ice Management Systems (no w known as IMS-ESS) licensed the technology from Ames and has discov ered a niche market for the lightweight, energy-efficient technology: unmanned aerial vehicles (UAVs). IMS-ESS systems now prevent damagi ng ice accumulation on military UAVs, allowing the vehicles to carry out crucial missions year round.

  3. Facile fabrication of iron-based superhydrophobic surfaces via electric corrosion without bath

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Qinghe [College of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Liu, Hongtao, E-mail: liuht100@126.com [College of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Chen, Tianchi [College of Mechanical & Electrical Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China); Wei, Yan; Wei, Zhu [College of Materials Science and Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116 (China)

    2016-04-30

    Graphical abstract: - Highlights: • This paper investigates the fabrication techniques towards superhydrophobic surface on carbon steel substrate via electric corrosion without a bath. • It has a vital significance to the industrialization of the fabrication of superhydrophobic surface on hard metal due to the advantages such as low cost, high efficiency, can be prepared in a large area, easy to construct in the field. • The preparation approach is so facile and time-saving that it delivers an opportunity to construct a superhydrophobic surface on carbon steel substrate and provides the feasibility for industrial application of superhydrophobic surface. • The as-prepared surface has many excellent properties, like low adhesive property, anti-corrosion ability, mechanical durability and anti-icing performance. - Abstract: Superhydrophobic surface is of wide application in the field of catalysis, lubrication, waterproof, biomedical materials, etc. The superhydrophobic surface based on hard metal is worth further study due to its advantages of high strength and wear resistance. This paper investigates the fabrication techniques towards superhydrophobic surface on carbon steel substrate via electric corrosion and studies the properties of as-prepared superhydrophobic surface. The hydrophobic properties were characterized by a water sliding angle (SA) and a water contact angle (CA) measured by the Surface tension instrument. A Scanning electron microscope was used to analyze the structure of the corrosion surface. The surface compositions were characterized by an Energy Dispersive Spectrum. The Electrochemical workstation was used to measure its anti-corrosion property. The anti-icing performance was characterized by a steam-freezing test in Environmental testing chamber. The SiC sandpaper and 500 g weight were used to test the friction property. The research result shows that the superhydrophobic surface can be successfully fabricated by electrocorrosion on

  4. The 'Guetsch' Alpine wind power test site; Alpine Test Site Guetsch. Handbuch und Fachtagung

    Energy Technology Data Exchange (ETDEWEB)

    Cattin, R.

    2008-12-15

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at the influence of icing-up on the operation of wind turbines in mountainous areas. Within the Swiss research project 'Alpine Test Site Guetsch', extensive icing studies were carried out at the Guetsch site near Andermatt, Switzerland. This document deals with the following subjects: Information about ice formation on structures, in particular with respect to wind turbines, standards and international research activities, wind measurements under icing-up conditions, estimation of the frequency of icing-up conditions, effects of icing-up on wind turbines, ice detection, measures available for de-icing and anti-icing as well as ice throw. A list of factors to be taken into account by the planners and operators of wind turbines in alpine environments is presented.

  5. Pancake bouncing on superhydrophobic surfaces

    Science.gov (United States)

    Liu, Yahua; Moevius, Lisa; Xu, Xinpeng; Qian, Tiezheng; Yeomans, Julia M.; Wang, Zuankai

    2014-07-01

    Engineering surfaces that promote rapid drop detachment is of importance to a wide range of applications including anti-icing, dropwise condensation and self-cleaning. Here we show how superhydrophobic surfaces patterned with lattices of submillimetre-scale posts decorated with nanotextures can generate a counter-intuitive bouncing regime: drops spread on impact and then leave the surface in a flattened, pancake shape without retracting. This allows a fourfold reduction in contact time compared with conventional complete rebound . We demonstrate that the pancake bouncing results from the rectification of capillary energy stored in the penetrated liquid into upward motion adequate to lift the drop. Moreover, the timescales for lateral drop spreading over the surface and for vertical motion must be comparable. In particular, by designing surfaces with tapered micro/nanotextures that behave as harmonic springs, the timescales become independent of the impact velocity, allowing the occurrence of pancake bouncing and rapid drop detachment over a wide range of impact velocities.

  6. Wettability-independent bouncing on flat surfaces mediated by thin air films

    Science.gov (United States)

    de Ruiter, Jolet; Lagraauw, Rudy; van den Ende, Dirk; Mugele, Frieder

    2015-01-01

    The impingement of drops onto solid surfaces plays a crucial role in a variety of processes, including inkjet printing, fog harvesting, anti-icing, dropwise condensation and spray coating. Recent efforts in understanding and controlling drop impact behaviour focused on superhydrophobic surfaces with specific surface structures enabling drop bouncing with reduced contact time. Here, we report a different universal bouncing mechanism that occurs on both wetting and non-wetting flat surfaces for both high and low surface tension liquids. Using high-speed multiple-wavelength interferometry, we show that this bouncing mechanism is based on the continuous presence of an air film for moderate drop impact velocities. This submicrometre `air cushion' slows down the incoming drop and reverses its momentum. Viscous forces in the air film play a key role in this process: they provide transient stability of the air cushion against squeeze-out, mediate momentum transfer, and contribute a substantial part of the energy dissipation during bouncing.

  7. Superhydrophobic porous networks for enhanced droplet shedding

    Science.gov (United States)

    Liu, Yahua; Wang, Zuankai

    2016-09-01

    Recent research has shown that the use of submillimeter-scale tapered post arrays could generate the so-called pancake bouncing, which is characterized by the fast shedding of impinging drops from the surface in a pancake shape without undergoing the retraction stage as observed on conventional superhydrophobic surfaces. Despite this exciting discovery, the fabrication of this unique superhydrophobic surface with tapered post arrays involves complex processes, hindering its wide applications in practical sectors. Here, we report on the facile strategy to prepare a new hierarchical multilayered superhydrophobic surface directly from commercially available porous matrix that allows for efficient drop shedding. Further study shows that the enhanced drop mobility observed on such a surface is attributed to the synergistic cooperation of hierarchical structures endowing an adequate energy storage and effective energy release. The facile fabrication of superhydrophobic surface with enhanced drop mobility may find many practical applications including anti-icing, dropwise condensation and self-cleaning.

  8. Active surfaces: Ferrofluid-impregnated surfaces for active manipulation of droplets

    Science.gov (United States)

    Khalil, Karim; Mahmoudi, Seyed Reza; Abu-Dheir, Numan; Varanasi, Kripa

    2014-11-01

    Droplet manipulation and mobility on non-wetting surfaces is of practical importance for diverse applications ranging from micro-fluidic devices, anti-icing, dropwise condensation, and biomedical devices. The use of active external fields has been explored via electric, acoustic, and vibrational, yet moving highly conductive and viscous fluids remains a challenge. Magnetic fields have been used for droplet manipulation; however, usually, the fluid is functionalized to be magnetic, and requires enormous fields of superconducting magnets when transitioning to diamagnetic materials such as water. Here we present a class of active surfaces by stably impregnating active fluids such as ferrofluids into a textured surface. Droplets on such ferrofluid-impregnated surfaces have extremely low hysteresis and high mobility such that they can be propelled by applying relatively low magnetic fields. Our surface is able to manipulate a variety of materials including diamagnetic, conductive and highly viscous fluids, and additionally solid particles.

  9. Electrostatic charging of jumping droplets

    Science.gov (United States)

    Miljkovic, Nenad; Preston, Daniel J.; Enright, Ryan; Wang, Evelyn N.

    2013-09-01

    With the broad interest in and development of superhydrophobic surfaces for self-cleaning, condensation heat transfer enhancement and anti-icing applications, more detailed insights on droplet interactions on these surfaces have emerged. Specifically, when two droplets coalesce, they can spontaneously jump away from a superhydrophobic surface due to the release of excess surface energy. Here we show that jumping droplets gain a net positive charge that causes them to repel each other mid-flight. We used electric fields to quantify the charge on the droplets and identified the mechanism for the charge accumulation, which is associated with the formation of the electric double layer at the droplet-surface interface. The observation of droplet charge accumulation provides insight into jumping droplet physics as well as processes involving charged liquid droplets. Furthermore, this work is a starting point for more advanced approaches for enhancing jumping droplet surface performance by using external electric fields to control droplet jumping.

  10. Study of superhydrophobic electrospun nanocomposite fibers for energy systems.

    Science.gov (United States)

    Asmatulu, Ramazan; Ceylan, Muhammet; Nuraje, Nurxat

    2011-01-18

    Polystyrene (PS) and polyvinyl chloride (PVC) fibers incorporated into TiO(2) nanoparticles and graphene nanoflakes were fabricated by an electrospinning technique, and then the surface morphology and superhydrophobicity of these electrospun nanocomposite fibers were investigated. Results indicated that the water contact angle of the nanocomposite fiber surfaces increases to 178° on the basis of the fiber diameter, material type, nanoscale inclusion, heat treatment, and surface porosity/roughness. This is a result of the formation of the Cassie-Baxter state in the fibers via the nanoparticle decoration, bead formation, and surface energy of the nanofiber surface. Consequently, these superhydrophobic nanocomposite fibers can be utilized in designing photoelectrodes of dye-sensitized solar cells (DSSCs) as self-cleaning and anti-icing materials for the long-term efficiency of the cells.

  11. Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aytug, Tolga; Simpson, John T.; Lupini, Andrew R.; Trejo, Rosa M.; Jellison, Gerald E.; Ivanov, Ilia N.; Pennycook, Stephen J.; Hillesheim, Daniel A.; Winter, Kyle O.; Christen, David K.; Hunter, Scott R.; Allen Haynes, J.

    2013-07-15

    Inspired by highly non-wetting natural biological surfaces (e.g., lotus leaves and water strider legs), artificial superhydrophobic surfaces that exhibit water droplet contact angles exceeding 150o have previously been constructed by utilizing various synthesis strategies.[ , , ] Such bio-inspired, water-repellent surfaces offer significant potential for numerous uses ranging from marine applications (e.g., anti-biofouling, anti-corrosion), anti-condensation (e.g., anti-icing, anti-fogging), membranes for selective separation (e.g., oil-water, gas-liquid), microfluidic systems, surfaces requiring reduced maintenance and cleaning, to applications involving glasses and optical materials.[ ] In addition to superhydrophobic attributes, for integration into device systems that have extended operational limits and overall improved performance, surfaces that also possess multifunctional characteristics are desired, where the functionality should match to the application-specific requirements.

  12. Highly Conductive Carbon Fiber Reinforced Concrete for Icing Prevention and Curing

    Directory of Open Access Journals (Sweden)

    Oscar Galao

    2016-04-01

    Full Text Available This paper aims to study the feasibility of highly conductive carbon fiber reinforced concrete (CFRC as a self-heating material for ice formation prevention and curing in pavements. Tests were carried out in lab ambient conditions at different fixed voltages and then introduced in a freezer at −15 °C. The specimens inside the freezer were exposed to different fixed voltages when reaching +5 °C for prevention of icing and when reaching the temperature inside the freezer, i.e., −15 °C, for curing of icing. Results show that this concrete could act as a heating element in pavements with risk of ice formation, consuming a reasonable amount of energy for both anti-icing (prevention and deicing (curing, which could turn into an environmentally friendly and cost-effective deicing method.

  13. Comparison of the Asphalt Pavement Deicing Technology%沥青路面除冰技术之比较

    Institute of Scientific and Technical Information of China (English)

    陈章

    2013-01-01

      道路结冰致使车轮与路面摩擦作用大大减弱,导致车辆打滑或刹车失灵,引起交通事故,阻塞交通运行,造成行人滑倒、摔伤等。本文通过对各种除冰技术的比较,给大家在选择除冰方法上提供借鉴。%Icy roads wil greatly decrease the friction force be-tween wheels of vehicles and roads, causing vehicle skid, brak-e failure, traffic jam or even traffic accidents. And pedestrians may slip down and get hurt. By comparing several techniques and methods of anti-icing and deicing, this thesis wants to give some suggestions for choosing the proper methods of anti-icin-g and deicing.

  14. Non-wetting droplets on hot superhydrophilic surfaces

    Science.gov (United States)

    Adera, Solomon; Raj, Rishi; Enright, Ryan; Wang, Evelyn N.

    2013-09-01

    Controlling wettability by varying surface chemistry and roughness or by applying external stimuli is of interest for a wide range of applications including microfluidics, drag reduction, self-cleaning, water harvesting, anti-corrosion, anti-fogging, anti-icing and thermal management. It has been well known that droplets on textured hydrophilic, that is superhydrophilic, surfaces form thin films with near-zero contact angles. Here we report an unexpected behaviour where non-wetting droplets are formed by slightly heating superhydrophilic microstructured surfaces beyond the saturation temperature (>5 °C). Although such behaviour is generally not expected on superhydrophilic surfaces, an evaporation-induced pressure in the structured region prevents wetting. In particular, the increased thermal conductivity and decreased vapour permeability of the structured region allows this behaviour to be observed at such low temperatures. This phenomenon is distinct from the widely researched Leidenfrost and offers an expanded parametric space for fabricating surfaces with desired temperature-dependent wettability.

  15. Convective Heat Transfer from Castings of Ice Roughened Surfaces in Horizontal Flight

    Science.gov (United States)

    Dukhan, Nihad; Vanfossen, G. James, Jr.; Masiulaniec, K. Cyril; Dewitt, Kenneth J.

    1995-01-01

    A technique was developed to cast frozen ice shapes that had been grown on a metal surface. This technique was applied to a series of ice shapes that were grown in the NASA Lewis Icing Research Tunnel on flat plates. Eight different types of ice growths, characterizing different types of roughness, were obtained from these plates, from which aluminum castings were made. Test strips taken from these castings were outfitted with heat flux gages, such that when placed in a dry wind tunnel, they could be used to experimentally map out the convective heat transfer coefficient in the direction of flow from the roughened surfaces. The effects on the heat transfer coefficient for parallel flow, which simulates horizontal flight, were studied. The results of this investigation can be used to help size heaters for wings, helicopter rotor blades, jet engine intakes, etc., or de-icing for anti-icing applications where the flow is parallel to the iced surface.

  16. Effect of Airplane Maintenance Materials on Corrosion Behavior of Dichromate Conversion Coating on Magnesium Alloy%重铬酸盐处理镁合金在航空化学品中的腐蚀行为研究

    Institute of Scientific and Technical Information of China (English)

    张亚博; 赵芯; 苏正良; 夏祖西

    2014-01-01

    The article describes main forms of corrosion of dichromate conversion coating on magnesium alloy in airplane maintenance materials. The composition and structure of dichromate conversion coating on magnesium alloy were investigated by means of SEM and XRD. The polarization curve and electrochemical impedance spectra of dichromate conversion coating on magnesium alloy were investigated by EG&G M273potentiostat. The results indicate that corrosion potential of dichromate conversion coating on magnesium alloy in Deicing/Anti-Icing Fluids of Runways and Taxiways according with AMS 1435, Cleaner according with AMS 1526, disinfectant according with AMS 1425 , Type I Deicing/Anti-Icing Fluids according with AMS 1424 between-1.5V and-1.6V. The corrosion potential of dichromate conversion coating on magnesium alloy is higher than magnesium alloy. The electrochemical impedance spectroscopy indicate that dichromate conversion coating on magnesium alloy in Type I Deicing/Anti-Icing Fluids according with AMS 1424 is adsorption-type inhibitor system;the electrode reactions in Deicing/Anti-Icing Fluids of Runways and Taxiways according with AMS 1435 is generate intermediate products. The electrode reactions in Cleaner according with AMS 1526 and disinfectant according with AMS 1425 were controlled by electro-chemical polarization.%本文介绍了重铬酸盐处理后的镁合金在航空化学品中的主要腐蚀形式,使用扫描电镜和XRD表征了铬酸盐转化膜的微观结构和组成,并通过EG&G M273恒电位仪测量在航空化学品种的极化曲线和电化学阻抗谱,试验结果表明处理后的镁合金在符合AMS 1435标准的机场道面除冰防冰液、符合标准AMS1526飞机清洗剂、符合AMS 1425标准的飞机消毒液、符合AMS 1424标准的I型飞机除冰防冰液中的腐蚀电位均在-1.5~-1.6V之间,明显比裸镁合金(-2.36V)的腐蚀电位高。从电化学阻抗谱上可以看出经重铬酸盐处

  17. Aircraft de-icer: Recycling can cut carbon emissions in half

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Eric P., E-mail: ejohnson@ecosite.co.uk

    2012-01-15

    Flight-safety regulations in most countries require aircraft to be ice-free upon takeoff. In icy weather, this means that the aircraft usually must be de-iced (existing ice is removed) and sometimes anti-iced (to protect against ice-reformation). For both processes, aircraft typically are sprayed with an 'antifreeze' solution, consisting mainly of glycol diluted with water. This de/anti-icing creates an impact on the environment, of which environmental regulators have grown increasingly conscious. The US Environmental Protection Agency (EPA), for example, recently introduced stricter rules that require airports above minimum size to collect de-icing effluents and send them to wastewater treatment. De-icer collection and treatment is already done at most major airports, but a few have gone one step further: rather than putting the effluent to wastewater, they recycle it. This study examines the carbon savings that can be achieved by recycling de-icer. There are two key findings. One, recycling, as opposed to not recycling, cuts the footprint of aircraft de-icing by 40-50% - and even more, in regions where electricity-generation is cleaner. Two, recycling petrochemical-based de-icer generates a 15-30% lower footprint than using 'bio' de-icer without recycling. - Highlights: Black-Right-Pointing-Pointer Carbon footprint of aircraft de-icing can be measured. Black-Right-Pointing-Pointer Recycling aircraft de-icer cuts the footprint of aircraft de-icing by 40-50%. Black-Right-Pointing-Pointer Recycling 'fossil' de-icer is lower carbon than not recycling 'bio' de-icer.

  18. Thermal mapping as a valuable tool for road weather forecast and winter road maintenance: an example from the Italian Alps

    Science.gov (United States)

    Todeschini, Ilaria; Di Napoli, Claudia; Pretto, Ilaria; Merler, Giacomo; Cavaliere, Roberto; Apolloni, Roberto; Antonacci, Gianluca; Piazza, Andrea; Benedetti, Guido

    2016-08-01

    During the winter period ice is likely to form on roads, making pavement surfaces slippery and increasing accident risk. Road surface temperature (RST) is one of the most important parameters in ice formation. The LIFE+ "CLEANROADS" project aims to forecast RSTs in advance in order to support road maintenance services in the timely and effective preparation of preventive anti-icing measures. This support is provided through a novel MDSS (Maintenance Decision Support System). The final goal of the project is to quantitatively demonstrate that the implemented MDSS is capable to minimize the consumption of chemical anti-icing reagents (e.g. sodium chloride) and the associated environmental (water and air) impact while maintaining the current high levels of road safety. In the CLEAN-ROADS system RSTs have been forecast by applying the numerical model METRo (Model of the Environment and Temperature of Roads) to a network of RWIS (Road Weather Information System) stations installed on a test route in the Adige Valley (Italy). This forecast is however local and does not take into account typical peculiarities along road network, such as the presence of road sections that are particularly prone to ice formation. Thermal mapping, i.e. the acquisition of mobile RST measurements through infrared thermometry, permits to (i) identify and map those sections, and (ii) extend the forecast from a RWIS station to adjacent areas. The processing of thermal mapping signals is however challenging because of random variations in the road surface emissivity. To overcome this we have acquired several thermal mapping traces along the test route during winter seasons 2014-2015 and 2015-2016. We have then defined a "characteristic" thermal fingerprint as a function of all its historical thermal mapping signals, and used it to spatialize local METRo forecasts. Preliminary results suggest the high potential of such a technique for winter road applications.

  19. 飞机除冰液在冰中的渗透性能影响因素分析%Research Aircraft Deicing Fluid Permeability of Ice

    Institute of Scientific and Technical Information of China (English)

    陈元; 李志强; 张帆; 彭华乔; 于新华

    2015-01-01

    In order to improve the ability of aircraft deicing fluid airworthiness certification, making a research and analysis of aircraft deicing fluid influence on the permeability of ice through temperature, freezing point, osmotic pressure and the molecular weight respectively, according to《AIR 6211 Ice Penetration Test Method for Runways and Taxiways Deicing/Anti-icing Chemicals》. The results show that the depth of aircraft deicing fluid on the penetration of ice decreases as the temperature is reduced. The permeability of Newtonian-fluid is better than non Newtonian-fluid at the same temperature. The permeability of aircraft deicing fluid has no direct relation to the freezing point and associated with osmotic pressure. Moreover, the higher pressure, the better permeability of ice.%为了提高飞机除冰液适航验证能力,根据《AIR 6211 Ice Penetration Test Method for Runways and Taxiways Dei-cing/Anti-icing Chemicals》标准试验方法,研究分析了温度、冰点、渗透压和分子大小对飞机除冰液渗透性能的影响。试验结果表明:随着温度的降低,飞机除冰液对冰的渗透性逐渐减小;在相同温度下,牛顿流体型除冰液的渗透性优于非牛顿流体型除冰液;飞机除冰液的冰点和渗透性无直接关系而与渗透压相关,且渗透压越大,对冰的渗透性越好。

  20. Femtosecond Laser Fabricate Wetting FunctionMicro-and Nanostructure on Aerial Aluminum Alloys Surface%飞秒激光制备航空用铝靶材表面润湿功能微纳结构的研究

    Institute of Scientific and Technical Information of China (English)

    吴先福; 白弋枫; 赵洪波; 周文彬; 陶海岩

    2016-01-01

    Over the years,aircraft's wetting function surface anti-icing technology receives much concern because of its many advantages such as not consuming energy and almost no additional volume and quality. Aluminum alloy has been used in civil aircraft widely, especially in shell and skeleton of aircraft. However, the wetting characteristics of original shell's surface don't have an excellent performance. It can effectively change the wetting properties of the surface by femtosecond laser-induced micro- and nanostructures preparation technology. In this paper, we prepared two kinds of typical micro- and nano-multiple structures. Experimental results show that, columnar micro- and nanostructures can achieve the super-hydrophobic surface property caused by the air provided by special double size multi-structure. More-over, trench like micro- and nanostructures make the surface show the super-hydrophilic properties powered by the open cavity capillary effect, and have orientation water delivery function. The realization of these wetting functions has important significance in application for the development of spacecraft anti-icing technology.%近年来,飞行器润湿功能外壳防冰技术以其不消耗能源、几乎不增加额外体积和质量等优点备受世界各国科学家及工程师的关注.铝合金材料一直广泛的应用于民用飞行器,特别是飞机外壳和骨架,然而原有外壳材料表面润湿特性表现中庸.通过飞秒激光微纳结构制备技术,可以有效改变其表面的润湿特性.利用飞秒激光在不同实验条件下,制备了两种典型的微纳复合结构,实验结果表明,柱型微纳结构以独特的双尺寸复合结构所提供的空气气模实现了表面超疏水特性.而沟槽型微纳结构以开放腔毛细管效应为原动力,使其展现了超亲水特性,并具备定向输水功能.这些润湿功能的实现对航空飞行器防冰技术的发展有着重要的应用意义.

  1. 铝基体超疏水表面结冰结霜特性研究%Characteristics of Ice and Frost Formation on Superhydrophobic Surfaces on Aluminum Substrates

    Institute of Scientific and Technical Information of China (English)

    徐文骥; 宋金龙; 孙晶; 窦庆乐

    2011-01-01

    采用中性电解液,通过电化学加工技术及氟化处理方法制备出铝基体超疏水表面,接触角达160°,滚动角小于5°,并在其上进行了结冰和结霜研究.在不同实验条件下研究超疏水表面的形貌、霜高随时间的变化,并与相同条件下的普通铝表面、吸水性表面进行了对比.结果表明,该超疏水表面经过50多次结霜、除霜后,仍具有很好的超疏水性能,表现出良好的重复性和耐久性;与普通铝表面相比,铝基体超疏水表面具有明显的抗结冰结霜性能,霜晶先出现在四周边缘处并逐渐蔓延到中间,但抑霜能力随着冷表面温度的降低而减小;与吸水性表面相比,超疏水表面在抗结冰结霜的同时能有效抑制表面质量的增加.%The superhydrophobic surface on aluminum substrate with water contact angle of 160° and contact angle hysteresis lower than 5° was fabricated by electrochemical machining with the neutral electrolyte and fluorination, then ice and frost formation on it was studied. The surface topography and frost thickness under different experimental conditions were investigated and compared with the superhydrophobic surface, ordinary aluminum surface and hydrophilic surface, respectively. The experimental results show that the surface still has good hydrophobic properties in reproducibility and durability after SO times frost and defrosting. Moreover, the superhydrophobic surface demonstrates the anti-icing and frosting capability eminently compared with ordinary aluminum surface, frost crystals appear arounding the edge of the superhydrophobic surface firstly, then spread gradually to the entire surface, but the anti-icing and frosting capability will reduce with the decrease of temperature of cold surfaces. Furthermore, the superhydrophbic surface can prevent the increasement of ice mass effectively compared with hydrophilic surface.

  2. Nanoscale deicing by molecular dynamics simulation

    Science.gov (United States)

    Xiao, Senbo; He, Jianying; Zhang, Zhiliang

    2016-07-01

    Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice adhesion strength by an aqueous water layer, and provide atomistic details that support previous experimental studies. Our results contribute quantitative comparison of nanoscale adhesion strength of ice on hydrophobic and hydrophilic surfaces, and supply for the first time theoretical references for understanding the mechanics at the atomistic origins of macroscale ice adhesion.Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice

  3. Highly durable superhydrophobic coatings with gradient density by movable spray method

    Science.gov (United States)

    Tenjimbayashi, Mizuki; Shiratori, Seimei

    2014-09-01

    Superhydrophobic surface is expected to be applied in anti-fouling, anti-icing, and anti-bacterial. However, practical use is interrupted by low mechanical strength, time-consuming process, and limited coating substrate. Here highly durable superhydrophobic coatings were prepared by simple and novel spraying method, which sprays with changing the "spray distance between substrate and spray" (SD), named "movable spray method." We prepared the solution that changes wettability and durability with spraying distance by mixing SiO2 nanoparticles and ethyl alpha cyanoacrylate polymer (EAC). Then, we evaluated the chemical components and surface morphologies of each spraying distance coatings (0 ˜ 50 cm) by XPS, SEM, and laser scanning microscope. It revealed that surface roughness and SiO2/EAC ratio increased as the SD increases. Thus, durable superhydrophobic coatings were designed by spraying with increasing SD gradually. Glow discharge-optical emission spectrometry analysis revealed that designed coatings showed the gradual increase of SiO2/EAC ratio. As a result, coatings prepared on glass, wood, or aluminum substrates maintained their superhydrophobicity up to the abrasion at 40 kPa. This movable spray method is simple coating by the wet process and prepares robust hydrophobic coating on complex shape and large area substrates. The gradient functional surface was found to have mechanical durability and superhydrophobicity, and wide area applications will be expected.

  4. Transparent self-cleaning lubricant-infused surfaces made with large-area breath figure patterns

    Science.gov (United States)

    Zhang, Pengfei; Chen, Huawei; Zhang, Liwen; Ran, Tong; Zhang, Deyuan

    2015-11-01

    Nepenthes pitcher inspired slippery lubricant-infused porous surfaces greatly impact the understanding of liquid-repellent surfaces construction and have attracted extensive attention in recent years due to their potential applications in self-cleaning, anti-fouling, anti-icing, etc. In this work, we have successfully fabricated transparent slippery lubricant-infused surfaces based on breath figure patterns (BFPs). Large-area BFPs with interconnected pores were initially formed on the glass substrate and then a suitable lubricant was added onto the surfaces. The interconnected pores in BFPs were able to hold the lubricant liquid in place and form a stable liquid/solid composite surface capable of repelling a variety of liquids. The liquid-repellent surfaces show extremely low critical sliding angles for various liquids, thus providing the surfaces with efficient self-cleaning property. It was also found that the liquid droplets' sliding behaviors on the surfaces were significantly influenced by the tilting angle of the substrate, liquid volume, liquid chemical properties, and pore sizes of the surfaces.

  5. Bioinspired, roughness-induced, water and oil super-philic and super-phobic coatings prepared by adaptable layer-by-layer technique

    Science.gov (United States)

    Brown, Philip S.; Bhushan, Bharat

    2015-09-01

    Coatings with specific surface wetting properties are of interest for anti-fouling, anti-fogging, anti-icing, self-cleaning, anti-smudge, and oil-water separation applications. Many previous bioinspired surfaces are of limited use due to a lack of mechanical durability. Here, a layer-by-layer technique is utilized to create coatings with four combinations of water and oil repellency and affinity. An adapted layer-by-layer approach is tailored to yield specific surface properties, resulting in a durable, functional coating. This technique provides necessary flexibility to improve substrate adhesion combined with desirable surface chemistry. Polyelectrolyte binder, SiO2 nanoparticles, and silane or fluorosurfactant layers are deposited, combining surface roughness and necessary chemistry to result in four different coatings: superhydrophilic/superoleophilic, superhydrophobic/superoleophilic, superhydrophobic/superoleophobic, and superhydrophilic/superoleophobic. The superoleophobic coatings display hexadecane contact angles >150° with tilt angles 160° with tilt angles <2°. One coating combines both oleophobic and hydrophobic properties, whilst others mix and match oil and water repellency and affinity. Coating durability was examined through the use of micro/macrowear experiments. These coatings display transparency acceptable for some applications. Fabrication via this novel combination of techniques results in durable, functional coatings displaying improved performance compared to existing work where either durability or functionality is compromised.

  6. New-type DC Ice-melting Disconnector and Its Application%新型直流融冰隔离开关及其应用

    Institute of Scientific and Technical Information of China (English)

    吴家林; 王亚莉; 何立新

    2013-01-01

    常规直流融冰电流跨接方案存在投资大、占地面积大、施工时间长、工作效率低、作业风险高、操作复杂、运行维护不便等缺点,通过对直流融冰跨接方案分析比较,针对直流融冰技术特点发明了一种新型直流融冰隔离开关并在实际工程中应用,为电网防冰减灾提供了新的技术手段,具有较高的推广和使用价值.%The conventional DC ice-melting current jumper scheme exists large investment, large occupied area, long construction time, low working efficiency, high operation risk, complex operation, operation and maintenance inconvenience shortcomings, through analyzing and comparing the DC ice-melting jumper scheme, aiming at the characteristics of DC ice-melting technology invented a new type of DC ice-melting disconnector and application in practical engineering, provides a new means for the anti icing disaster technology in power grid. It has higher popularization and use value.

  7. Factors affecting the spontaneous motion of condensate drops on superhydrophobic copper surfaces.

    Science.gov (United States)

    Feng, Jie; Qin, Zhaoqian; Yao, Shuhuai

    2012-04-10

    The coalescence-induced condensate drop motion on some superhydrophobic surfaces (SHSs) has attracted increasing attention because of its potential applications in sustained dropwise condensation, water collection, anti-icing, and anticorrosion. However, an investigation of the mechanism of such self-propelled motion including the factors for designing such SHSs is still limited. In this article, we fabricated a series of superhydrophobic copper surfaces with nanoribbon structures using wet chemical oxidation followed by fluorization treatment. We then systematically studied the influence of surface roughness and the chemical properties of as-prepared surfaces on the spontaneous motion of condensate drops. We quantified the "frequency" of the condensate drop motion based on microscopic sequential images and showed that the trend of this frequency varied with the nanoribbon structure and extent of fluorination. More obvious spontaneous condensate drop motion was observed on surfaces with a higher extent of fluorization and nanostructures possessing sufficiently narrow spacing and higher perpendicularity. We attribute this enhanced drop mobility to the stable Cassie state of condensate drops in the dynamic dropwise condensation process that is determined by the nanoscale morphology and local surface energy.

  8. A robust, melting class bulk superhydrophobic material with heat-healing and self-cleaning properties

    Science.gov (United States)

    Ramakrishna, S.; Santhosh Kumar, K. S.; Mathew, Dona; Reghunadhan Nair, C. P.

    2015-01-01

    Superhydrophobic (SH) materials are essential for a myriad of applications such as anti-icing and self-cleaning due to their extreme water repellency. A single, robust material simultaneously possessing melt-coatability, bulk water repellency, self-cleanability, self-healability, self-refreshability, and adhesiveness has been remaining an elusive goal. We demonstrate a unique class of melt-processable, bulk SH coating by grafting long alkyl chains on silica nanoparticle surface by a facile one-step method. The well-defined nanomaterial shows SH property in the bulk and is found to heal macro-cracks on gentle heating. It retains wettability characteristics even after abrading with a sand paper. The surface regenerates SH features (due to reversible self-assembly of nano structures) quickly at ambient temperature even after cyclic water impalement, boiling water treatment and multiple finger rubbing tests. It exhibits self-cleaning properties on both fresh and cut surfaces. This kind of coating, hitherto undisclosed, is expected to be a breakthrough in the field of melt-processable SH coatings. PMID:26679096

  9. Nature inspired structured surfaces for biomedical applications.

    Science.gov (United States)

    Webb, H K; Hasan, J; Truong, V K; Crawford, R J; Ivanova, E P

    2011-01-01

    Nature has created an array of superhydrophobic surfaces that possess water-repellent, self-cleaning and anti-icing properties. These surfaces have a number of potential applications in the biomedical industry, as they have the potential to control protein adsorption and cell adhesion. Natural superhydrophobic surfaces are typically composed of materials with a low intrinsic surface free-energy (e.g the cuticular waxes of lotus leaves and insect wings) with a hierarchical structural configuration. This hierarchical surface topography acts to decrease the contact area of water droplets in contact with the surface, thereby increasing the extent of the air/water interface, resulting in water contact angles greater than 150º. In order to employ these surfaces in biotechnological applications, fabrication techniques must be developed so that these multi-scale surface roughness characteristics can be reproduced. Additionally, these fabrication techniques must also be able to be applied to the material required for the intended application. An overview of some of the superhydrophobic surfaces that exist in nature is presented, together with an explanation of the theories of their wettability. Also included is a description of some of the biomedical applications of superhydrophobic surfaces and fabrication techniques that can be used to mimic superhydrophobic surfaces found in nature.

  10. Room Temperature Characteristics of Polymer-Based Low Ice Adhesion Surfaces

    Science.gov (United States)

    He, Zhiwei; Vågenes, Elisabeth T.; Delabahan, Chrisrosemarie; He, Jianying; Zhang, Zhiliang

    2017-02-01

    Ice adhesion is mainly dictated by surface properties, and water wettability is frequently correlated with ice adhesion strength. However, these established correlations are limited to high ice adhesion and become invalid when the ice adhesion strength is low. Here we carried out an experimental study to explore the relationships between low ice adhesion strength and room temperature surface properties. A variety of room temperature properties of 22 polymer-based hydrophilic and hydrophobic samples consisting of both low and high ice adhesion surfaces were analysed. The properties investigated include water adhesion force, water wettability, roughness, elastic modulus and hardness. Our results show that low ice adhesion strength does not correlate well with water contact angle and its variants, surface roughness and hardness. Low elastic modulus does not guarantee low ice adhesion, however, surfaces with low ice adhesion always show low elastic modulus. Low ice adhesion (below 60 kPa) of tested surfaces may be determinative of small water adhesion force (from 180 to 270 μN). Therefore, measurement of water adhesion force may provide an effective strategy for screening anti-icing or icephobic surfaces, and surfaces within specific values of water adhesion force will possibly lead to a low ice adhesion.

  11. Wenzel Wetting on Slippery Rough Surfaces

    Science.gov (United States)

    Stogin, Birgitt; Dai, Xianming; Wong, Tak-Sing

    2015-11-01

    Liquid repellency is an important surface property used in a wide range of applications including self-cleaning, anti-icing, anti-biofouling, and condensation heat transfer, and is characterized by apparent contact angle (θ*) and contact angle hysteresis (Δθ*). The Wenzel equation (1936) predicts θ* of liquids in the Wenzel state, and is one of the most fundamental equations in the wetting field. However, droplets in the Wenzel state on conventional rough surfaces exhibit large Δθ* , making it difficult to experimentally verify the model with precision. As a result, precise verification of the Wenzel wetting model has remained an open scientific question for the past 79 years. Here we introduce a new class of liquid-infused surfaces called slippery rough surfaces -- surfaces with significantly reduced Δθ* compared to conventional rough surfaces--and use them to experimentally assess the Wenzel equation with the highest precision to date. We acknowledge the funding support by National Science Foundation (NSF) CAREER Award #: 1351462 and Office of Navy Research MURI Award #: N00014-12-1-0875. Stogin acknowledges the support from the NSF Graduate Research Fellowship (Grant No. DGE1255832).

  12. The interaction of radio frequency electromagnetic fields with atmospheric water droplets and applications to aircraft ice prevention. Thesis

    Science.gov (United States)

    Hansman, R. J., Jr.

    1982-01-01

    The feasibility of computerized simulation of the physics of advanced microwave anti-icing systems, which preheat impinging supercooled water droplets prior to impact, was investigated. Theoretical and experimental work performed to create a physically realistic simulation is described. The behavior of the absorption cross section for melting ice particles was measured by a resonant cavity technique and found to agree with theoretical predictions. Values of the dielectric parameters of supercooled water were measured by a similar technique at lambda = 2.82 cm down to -17 C. The hydrodynamic behavior of accelerated water droplets was studied photograhically in a wind tunnel. Droplets were found to initially deform as oblate spheroids and to eventually become unstable and break up in Bessel function modes for large values of acceleration or droplet size. This confirms the theory as to the maximum stable droplet size in the atmosphere. A computer code which predicts droplet trajectories in an arbitrary flow field was written and confirmed experimentally. The results were consolidated into a simulation to study the heating by electromagnetic fields of droplets impinging onto an object such as an airfoil. It was determined that there is sufficient time to heat droplets prior to impact for typical parameter values. Design curves for such a system are presented.

  13. Deicing System Protects General Aviation Aircraft

    Science.gov (United States)

    2007-01-01

    Kelly Aerospace Thermal Systems LLC worked with researchers at Glenn Research Center on deicing technology with assistance from the Small Business Innovation Research (SBIR) program. Kelly Aerospace acquired Northcoast Technologies Ltd., a firm that had conducted work on a graphite foil heating element under a NASA SBIR contract and developed a lightweight, easy-to-install, reliable wing and tail deicing system. Kelly Aerospace engineers combined their experiences with those of the Northcoast engineers, leading to the certification and integration of a thermoelectric deicing system called Thermawing, a DC-powered air conditioner for single-engine aircraft called Thermacool, and high-output alternators to run them both. Thermawing, a reliable anti-icing and deicing system, allows pilots to safely fly through ice encounters and provides pilots of single-engine aircraft the heated wing technology usually reserved for larger, jet-powered craft. Thermacool, an innovative electric air conditioning system, uses a new compressor whose rotary pump design runs off an energy-efficient, brushless DC motor and allows pilots to use the air conditioner before the engine even starts

  14. Heat and mass transfer during ice accretion on aircraft wings with an improved roughness model

    Energy Technology Data Exchange (ETDEWEB)

    Fortin, Guy; Ilinca, Adrian [Groupe eolien, Universite du Quebec a Rimouski, 300 allee des Ursulines, Rimouski, PQ (Canada); Laforte, Jean-Louis [Laboratoire international des materiaux Anti-givre, Universite du Quebec a Chicoutimi, 555 Boulevard Universite, Chicoutimi, PQ (Canada)

    2006-06-15

    This paper presents the thermodynamic model used in the numerical simulation of ice accreted on an airfoil surface in wet and dry regimes developed at AMIL (Anti-Icing Materials International Laboratory), in a joint project with CIRA (Italian Aerospace Research Center). The thermodynamic model combines mass and heat balance equations to an analytical representation of water states over the airfoil to calculate the surface roughness and masses of remaining, run-back, and shedding liquid water. The water state on the surface is represented in the form of beads, film or rivulets, each situation corresponding to a particular roughness height which has a major impact on the heat transfer coefficients necessary for the heat and mass balances. The model has been tested for severe icing conditions at six different temperatures corresponding to dry, mixed and wet accretion. Water mass, roughness and heat transfer convection coefficients over the airfoil surface are presented. The thermodynamic model combined with an air flow, water trajectory, and geometric model provides accurate results. It generates the complex ice shapes observed on the wing profile, and the numerical ice shapes profiles agree well with those obtained in wind tunnel experiments. (author)

  15. Proceedings of the 11. International Workshop on Atmospheric Icing of Structures (IWAIS 2005)

    Energy Technology Data Exchange (ETDEWEB)

    Farzaneh, M. (ed.) [Quebec Univ., Chicoutimi, PQ (Canada). Icing Research Building; Goel, A.P. (ed.) [Hydro One, Toronto, ON (Canada)

    2005-07-01

    The widespread impacts and related costs of atmospheric icing were demonstrated in the ice storm that struck Quebec and eastern Ontario in January 1998. The storm incurred losses in the billions of dollars, caused extended power failures, and affected approximately 5.5 million people. The aim of this conference was to regroup as many icing experts and specialists as possible to facilitate interaction conducive to finding practical, safe and economical solutions to atmospheric icing. Recent developments in icing models were reviewed, as well as new approaches to data collection. New technologies in de-icing were presented, and issues concerning the behaviour of electrical equipment during icing events were discussed. The importance of finding adequate practical solutions to help to protect strategic infrastructures exposed to icing was emphasized. The conference was divided into the following 7 sections: (1) ice and snow climate; (2) modelling and simulation of icing; (3) field observations, data gathering and information; (4) impact of ice and snow on insulator performance; (5) design for icing; (6) behaviour of ice or snow-covered power equipment; (7) de-icing and anti-icing techniques. Sixty-eight papers were presented at this conference, all of which were catalogued for inclusion in this database. refs., tabs., figs.

  16. Wind tunnel simulation of icing conditions on a NACA 63-415 blade profile found at Murdochville during the 2004-2005 measuring study of a Vesta V80 1.8 MW wind turbine; Simulation en soufflerie sur un profil NACA 63-415 des conditions de givrage relevees a Murchochville durant la campagne de mesure 2004-2005 selon une eolienne Vestas V80 de 1.8 MW

    Energy Technology Data Exchange (ETDEWEB)

    Hochart, C.; Fortin, G.; Perron, J. [Quebec Univ., Chicoutimi, PQ (Canada). Anti-Icing Materials International Laboratory; Ilinca, A. [Quebec Univ., Rimouski, PQ (Canada). Wind Energy Group

    2005-12-15

    Frost accumulation was measured on the NACA 63 415 blade profile of a Vesta V80, 1.8 MW wind turbine during refrigerated wind tunnel tests conducted at the Anti-Icing Materials International Laboratory (AMIL) in Chicoutimi, Quebec in late 2005. The purpose of the study was to reproduce frost conditions measured in Murdochville, Quebec during the period of December 2004 to May 2005. The loss of mass was measured and the form of frost deposited was examined along with the lift and augmentation of drag. Thirteen tests were conducted with various frost precipitation. The meteorological data that was collected included wind velocity, wind direction, air temperature, relative humidity, barometric pressure and solar radiation. The icing events resulting from freezing fog or wet snow were characterized by measuring the growth rate of ice, duration of the icing event and the ice accretion regime. Simulations of frost precipitation and moisture, as well as technical problems encountered during the tests were described. The experiment made it possible to evaluate the impact of ice and frost on wind turbine blade. The model was able to demonstrate the initial angle timing when the strength induced by the frost was too big compared to the strength of lift, and when the drag became negative, causing the wind turbine to stop turning. 38 refs., 27 tabs.

  17. Characterization of meteorological and ice conditions at Noranda's abandoned mine site in Murdochville during the 2004-2005 measuring campaign; Characterisation des conditions meteorologiques et du givre sur le site de l'ancienne mine de Noranda a Murdochville durant la campagne de mesure 2004-2005

    Energy Technology Data Exchange (ETDEWEB)

    Fortin, G.; Hochart, C.; Perron, J. [Quebec Univ., Chicoutimi, PQ (Canada). Anti-Icing Materials International Laboratory; Ilinca, A. [Quebec Univ., Rimouski, PQ (Canada). Wind Energy Group

    2005-08-15

    A centre of integrated research and technology regarding wind energy in nordic climates has been established based on meteorological data collected from November 30, 2004 to May 24, 2005 at an abandoned Noranda mine in the town of Murdochville, Quebec. Results were compared with frost accumulation measured on the NACA 63 415 turbine blade profile during refrigerated wind tunnel tests conducted at the Anti-Icing Materials International Laboratory (AMIL) in Chicoutimi, Quebec in late 2005. Loss of lift and increased drag during frost periods were measured during the laboratory tests. Two dome anemometers were used to measure the wind intensity, wind direction, air temperature, relative humidity, barometric pressure, and sunlight. The parameters used to measure frost were the liquid content, diameter of water droplets, the density of the ice, the dew point, and the ice accumulation rate. The degree of potential danger to wind turbines was also calculated from the measured data. During the measuring campaign, there were 13 events of fog during frost periods, and 5 events of sleet that were registered. The month of March was shown to be the most vulnerable to frost followed by April, February, January. It was recommended that the model be modified to estimate the turning speed of wind turbines by adding a factor that keeps track of the increasing air velocity produced by the acceleration of the wind. 100 figs., 28 tabs.

  18. Experimental study of the use of icephobic coatings on wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Adomou, M.; Perron, J.; Fortin, G. [Quebec Univ., Chicoutimi, PQ (Canada). Anti-Icing Materials International Laboratory

    2010-07-01

    Accreted ice on wind turbine blades can lead to energy production losses, mechanical overloads, and ice shedding. Current de-icing systems have a high energy consumption rate and can lead to potential run-back water effects. This presentation discussed a study conducted to investigate the use of ice-phobic coatings as a means of protecting wind turbines during cold weather. The study examined the behaviour of various coatings on wind turbine blades under icing conditions and investigated the possibility of reducing the surface temperature of heated blades with the addition of ice-phobic or hydrophobic coatings. The performance of the thermal systems coupled with the coatings was also investigated. The coatings included: (1) a polyurethane plastic film, (2) a silicone-epoxy composite, (3) a fluorinated resin, and (4) a fluoroethane compound. The coatings were applied to a NACA airfoil placed in an icing wind tunnel. Various accretion regimes, wind speeds, and temperatures were studied. Results of the study showed that the coatings are effective against run-back effects during anti-icing operations, and may increase production gains from 4 to 6 per cent. tabs., figs.

  19. Ice shedding from overhead electrical lines by mechanical breaking : a ductile model for viscoplastic behaviour of atmospheric ice

    Energy Technology Data Exchange (ETDEWEB)

    Eskandarian, M.

    2005-07-01

    The mechanical characteristics of power line components need improvement in order to avoid power failures during severe ice storms. Atmospheric icing of overhead power lines creates electrical and mechanical problems in the transmission network. The successful development of anti-icing and de-icing techniques requires good knowledge of the adherence and bulk strength characteristics of atmospheric ice. This study presented a model for viscoplastic behaviour of porous atmospheric ice in the ductile region. The model was then modified to consider the effects of cracking activities to predict the material behaviour in transition and brittle regions. The following general methodologies were followed in this research for describing the ductile behaviour of porous atmospheric ice: instantaneous elastic strain; delayed viscoelastic strain; and, permanent plastic strain. The scientific contributions of this study include a classification of atmospheric ice structure on power lines on the basis of its grain shape and c-axis orientation. This thesis also presented 3 computer codes in Maple Mathematical Program for determining the elastic moduli of various types of freshwater ice; a poroelastic model for modifying the elastic moduli of porous atmospheric ice; a cap-model plasticity for various types of porous atmospheric ice; new freshwater ice yield envelopes in ductile regions that take porosity into account by means of an elliptical moving cap; and a newly developed user-defined material subroutine for viscoplastic behaviour of atmospheric ice in ductile region including the poroelastic, viscoelastic, and cap-model plasticity.

  20. Keeping a surface ice/frost free with electro-conducting water-repellent coatings

    Science.gov (United States)

    Das, Arindam; Kapatral, Shreyas; Megaridis, Constantine M.

    2013-11-01

    Ice/frost formation on aircraft, wind turbines, power grids, marine vessels, telecommunication devices, etc. has propelled scientific research on surfaces that facilitate the removal of the water solid phase or retard its formation. Superhydrophobic, self-cleaning surfaces have been investigated recently (Jung et al., Langmuir 2011) for their passive anti-icing properties. Although superhydrophobic surfaces have been shown to delay the onset of frosting and icing, they cannot prevent it entirely. Hence active deicing/defrosting approaches are required to keep surfaces free of ice/frost. Defrosting experiments have been carried out on glass substrates coated with textured polymeric nanocomposite films of different surface wettability, porosity and roughness. A strong influence of these parameters on condensation, condensation frosting and defrosting was observed. The coatings are electro-conducting, thus allowing skin heating at the interface between ice and the substrate. Sustained ice- and frost-free operation is demonstrated at substrate temperatures well below the freezing point and in humid ambient atmospheres. Supported by NSF Grant CBET-1066426.

  1. Ice Formation Delay on Penguin Feathers

    Science.gov (United States)

    Alizadehbirjandi, Elaheh; Tavakoli-Dastjerdi, Faryar; St. Leger, Judy; Davis, Stephen H.; Rothstein, Jonathan P.; Kavehpour, H. Pirouz

    2015-11-01

    Antarctic penguins reside in a harsh environment where air temperature may reach -40 °C with wind speed of 40 m/s and water temperature remains around -2.2 °C. Penguins are constantly in and out of the water and splashed by waves, yet even in sub-freezing conditions, the formation of macroscopic ice is not observed on their feathers. Bird feathers are naturally hydrophobic; however, penguins have an additional hydrophobic coating on their feathers to reinforce their non-wetting properties. This coating consists of preen oil which is applied to the feathers from the gland near the base of the tail. The combination of the feather's hydrophobicity and surface texture is known to increase the contact angle of water drops on penguin feathers to over 140 ° and classify them as superhydrophobic. We here develop an in-depth analysis of ice formation mechanism on superhydrophobic surfaces through careful experimentations and development of a theory to address how ice formation is delayed on these surfaces. Furthermore, we investigate the anti-icing properties of warm and cold weather penguins with and without preen oil to further design a surface minimizing the frost formation which is of practical interest especially in aircraft industry.

  2. Controlled hydrophilic/hydrophobic property of silica films by manipulating the hydrolysis and condensation of tetraethoxysilane

    Science.gov (United States)

    Yang, Xin; Zhu, Liqun; Chen, Yichi; Bao, Baiqing; Xu, Jinlong; Zhou, Weiwei

    2016-07-01

    Controlling surface wettability is an important road to afford the materials with anticipated functional properties, such as anti-fogging, anti-icing and self-cleaning. Manipulating the surface topography and chemical composition is a promising strategy to achieve the expected functional properties. Herein, we concurrently realized the control of surface topography and chemical composition of the film materials via exploiting a simply one step method through the hydrolysis and condensation of tetraethoxysilane (TEOS) to form silica sol-gel films. By adjusting the amount of water, TEOS and basic catalyst, the hydrophilic or hydrophobic chemical groups on the silica particles surface were well controlled. As a result, the sol-gel silica films exhibiting a controllable and wide range contact angles from 7.7 ± 1.5° to 121.6 ± 1.8° were obtained by this simple one-step method. The inorganic nonmetallic, metallic and polymer materials surface could maintain different wettability by the modification of controlled wettability silica films. Furthermore the wettability of silica film could be easily changed from hydrophobicity to superhydrophilicity through a heat-treatment due to the decrease of hydrophobic chemical groups conforming to the time-temperature equivalence principle. Raising temperature and extending holding time were equivalent to chemical bond breaking which result in the wettability change of silica films.

  3. Facile and cost-effective fabrication of patternable superhydrophobic surfaces via salt dissolution assisted etching

    Science.gov (United States)

    Choi, Dongwhi; Yoo, Jaewon; Park, Sang Min; Kim, Dong Sung

    2017-01-01

    Superhydrophobic surfaces with extremely low wettability have attracted attention globally along with their remarkable characteristics such as anti-icing, anti-sticking, and self-cleaning. In this study, a facile and cost-effective approach of fabricating patternable superhydrophobic surfaces, which can be applied on various substrates (including large area and 3D curvilinear substrates), is proposed with a salt-dissolution-assisted etching process. This novel proposal is environmentally benign (entirely water-based and fluorine-free process). The only required ingredients to realize superhydrophobic surfaces are commercially available salt particles, polydimethylsiloxane (PDMS), and water. No expensive equipment or complex process control is needed. The fabricated superhydrophobic surface shows high static contact angle (∼151°) and a low sliding angle (∼6°), which correspond to the standards of superhydrophobicity. This surface also shows corrosive liquids (acid/alkali)-resistant characteristics. Moreover, the self-cleaning ability of the fabricated surfaces is explored. As a proof-of-concept application of the present approach, the spatially controllable superhydrophobic patterns on flat/curvilinear substrates are directly drawn with a minimum feature size of 500 μm without the use of expensive tooling, dies, or lithographic masks.

  4. Coalescence-induced nanodroplet jumping

    Science.gov (United States)

    Cha, Hyeongyun; Xu, Chenyu; Sotelo, Jesus; Chun, Jae Min; Yokoyama, Yukihiro; Enright, Ryan; Miljkovic, Nenad

    2016-10-01

    Water vapor condensation on superhydrophobic surfaces has received much attention in recent years due to the ability of such surfaces to shed microscale water droplets via coalescence-induced droplet jumping, resulting in heat transfer, anti-icing, and self-cleaning performance enhancement. Here we report the coalescence-induced removal of water nanodroplets (R ≈500 nm ) from superhydrophobic carbon nanotube (CNT) surfaces. The two-droplet coalescence time is measured for varying droplet Ohnesorge numbers, confirming that coalescence prior to jumping is governed by capillary-inertial dynamics. By varying the conformal hydrophobic coating thickness on the CNT surface, the minimum jumping droplet radius is shown to increase with increasing solid fraction and decreasing apparent advancing contact angle, allowing us to explore both hydrodynamic limitations stemming from viscous dissipation and surface adhesion limitations. We find that, even for the smallest nanostructure length scale (≤100 nm) and lowest surface adhesions, nonideal surface interactions and the evolved droplet morphology play defining roles in limiting the minimum size for jumping on real surfaces. The outcomes of this work demonstrate the ability to passively shed nanometric water droplets, which has the potential to further increase the efficiency of systems that can harness jumping droplets for a wide range of energy and water applications.

  5. User's Manual for LEWICE Version 3.2

    Science.gov (United States)

    Wright, William

    2008-01-01

    A research project is underway at NASA Glenn to produce a computer code which can accurately predict ice growth under a wide range of meteorological conditions for any aircraft surface. This report will present a description of the code inputs and outputs from version 3.2 of this software, which is called LEWICE. This version differs from release 2.0 due to the addition of advanced thermal analysis capabilities for de-icing and anti-icing applications using electrothermal heaters or bleed air applications, the addition of automated Navier-Stokes analysis, an empirical model for supercooled large droplets (SLD) and a pneumatic boot option. An extensive effort was also undertaken to compare the results against the database of electrothermal results which have been generated in the NASA Glenn Icing Research Tunnel (IRT) as was performed for the validation effort for version 2.0. This report will primarily describe the features of the software related to the use of the program. Appendix A has been included to list some of the inner workings of the software or the physical models used. This information is also available in the form of several unpublished documents internal to NASA. This report is intended as a replacement for all previous user manuals of LEWICE. In addition to describing the changes and improvements made for this version, information from previous manuals may be duplicated so that the user will not need to consult previous manuals to use this software.

  6. Numerical investigation on super-cooled large droplet icing of fan rotor blade in jet engine

    Science.gov (United States)

    Isobe, Keisuke; Suzuki, Masaya; Yamamoto, Makoto

    2014-10-01

    Icing (or ice accretion) is a phenomenon in which super-cooled water droplets impinge and accrete on a body. It is well known that ice accretion on blades and vanes leads to performance degradation and has caused severe accidents. Although various anti-icing and deicing systems have been developed, such accidents still occur. Therefore, it is important to clarify the phenomenon of ice accretion on an aircraft and in a jet engine. However, flight tests for ice accretion are very expensive, and in the wind tunnel it is difficult to reproduce all climate conditions where ice accretion can occur. Therefore, it is expected that computational fluid dynamics (CFD), which can estimate ice accretion in various climate conditions, will be a useful way to predict and understand the ice accretion phenomenon. On the other hand, although the icing caused by super-cooled large droplets (SLD) is very dangerous, the numerical method has not been established yet. This is why SLD icing is characterized by splash and bounce phenomena of droplets and they are very complex in nature. In the present study, we develop an ice accretion code considering the splash and bounce phenomena to predict SLD icing, and the code is applied to a fan rotor blade. The numerical results with and without the SLD icing model are compared. Through this study, the influence of the SLD icing model is numerically clarified.

  7. Unconventional Approach for Demineralization of Deproteinized Crustacean Shells for Chitin Production

    Directory of Open Access Journals (Sweden)

    N. S. Mahmoud

    2007-01-01

    Full Text Available Chitin is a versatile environmentally friendly modern material. It has a wide range of applications in areas such as water treatment, pulp and paper, biomedical devices and therapies, cosmetics, membrane technology and biotechnology and food applications. Crustacean waste is the most important chitin source for commercial use. Demineralization is an important step in the chitin purification process from crustacean waste. The conventional method of demineralization includes the use of strong acid (commonly HCl that harms the physiochemical properties of chitin, results in a harmful effluent wastewater and increases the cost of chitin purification process. The current study proposes the use of organic acids (lactic and acetic produced by cheese whey fermentation to demineralize microbially deproteinized shrimp shells. The effects of acid type, demineralization condition, retention time and shells to acid ratio were investigated. The study showed that the effectiveness of using lactic and/or acetic acids for demineralization of shrimp shells was comparable to that of using hydrochloric acid. Using organic acids for demineralization is a promising concept, since organic acids are less harmful to the environment, can preserve the characteristics of the purified chitin and can be produced from low cost biomass such as cheese whey. In addition, the resulted organic salts from the demineralization process can be used as a food preservative and/or an environmentally friendly de-icing/anti-icing agents.

  8. An Experimental Investigation on the Impingement of Water Droplets onto Superhydrophobic Surfaces Pertinent to Aircraft Icing Phenomena

    Science.gov (United States)

    Li, Haixing; Waldman, Rye; Hu, Hui

    2015-11-01

    Superhydrophobic surfaces have self-cleaning properties that make them promising candidates as anti-icing solutions for various engineering applications, including aircraft anti-/de-icing. However, under sufficient external pressure, the liquid water on the surface can transition to a wetted state, defeating the self-cleaning properties of superhydrpphobic surfaces. In the present study, an experimental investigation was conducted to quantify the transient behavior of water droplets impinging onto test surfaces with different hydrophobicity properties under different environmental icing conditions. The experiments were performed in the Icing Research Tunnel of Iowa State University (IRT-ISU) with a NACA0012 airfoil. In addition to using a high-speed imaging system to reveal transient behavior of water droplets impinging onto test surfaces with different hydrophobicity properties, an IR thermometry was also used to quantify the unsteady heat transfer and dynamic phase changing process within the water droplets after impingement onto the test plates with different frozen cold temperatures. The high-speed imaging results were correlated with the quantitatively temperature measurements to elucidate underlying physics in order to gain further insight into the underlying physics pertinent to aircraft icing phenomena. The research work is partially supported by NASA with grant number NNX12AC21A and National Science Foundation under award numbers of CBET-1064196 and CBET-1435590.

  9. Self-propelled droplet behavior during condensation on superhydrophobic surfaces

    Science.gov (United States)

    Chu, Fuqiang; Wu, Xiaomin; Zhu, Bei; Zhang, Xuan

    2016-05-01

    Self-propelled droplet motion has applications in various engineering fields such as self-cleaning surfaces, heat transfer enhancement, and anti-icing methods. A superhydrophobic surface was fabricated using two simultaneous chemical reactions with droplet condensation experiments performed on the horizontal superhydrophobic surface to characterize the droplet behavior. The droplet behavior is classified into three types based on their motion features and leftover marks as immobile droplet coalescence, self-propelled droplet jumping, and self-propelled droplet sweeping. This study focuses on the droplet sweeping that occurs due to the ultra-small rolling angle of the superhydrophobic surface, where the resulting droplet sweeps along the surface, merging with all the droplets it meets and leaving a long, narrow, clear track with a large droplet at the end of the track. An easy method is developed to predict the droplet sweeping direction based on the relative positions of the droplets just before coalescence. The droplet sweeping always absorbs dozens of droplets and is not limited by the surface structures; thus, this sweeping has many useful applications. In addition, the relationships between the droplet behavior and the number of participating droplets are also analyzed statistically.

  10. 碳纤维-玻纤格栅抗凝冰沥青路面对策研究%Ice-melting Countermeasure Research of Carbon Fiber-glass Fiber Grille Asphalt Pavement

    Institute of Scientific and Technical Information of China (English)

    李红; 张谢东

    2013-01-01

    针对贵州地区凝冰危害等级,为了制订与凝冰危害等级相对应的抗凝冰路面响应对策,采取了将凝冰危害等级转换为凝冰厚度指标后再进一步研究抗凝冰路面响应对策的策略.在进行指标转换后,进一步研究了碳纤维-玻纤格栅抗凝冰沥青路面的融凝冰功率-升温时间关系、融凝冰能力,最后提出了具体的响应贵州地区凝冰危害的对策.%For the Guizhou province ice warning level,to make the anti-ice asphalt pavement response measures adapt for the ice warning level,the paper converted the warning level to ice thickness indicators before studying the ice-melting countermeasures.Then the paper further studied the relationship of ice-melting power-heating-up-time and ice-melting-ability of the pavement,and finally put forward specific response countermeasures to the ice warning.

  11. Nanoscale deicing by molecular dynamics simulation.

    Science.gov (United States)

    Xiao, Senbo; He, Jianying; Zhang, Zhiliang

    2016-08-14

    Deicing is important to human activities in low-temperature circumstances, and is critical for combating the damage caused by excessive accumulation of ice. The aim of creating anti-icing materials, surfaces and applications relies on the understanding of fundamental nanoscale ice adhesion mechanics. Here in this study, we employ all-atom modeling and molecular dynamics simulation to investigate ice adhesion. We apply force to detach and shear nano-sized ice cubes for probing the determinants of atomistic adhesion mechanics, and at the same time investigate the mechanical effect of a sandwiched aqueous water layer between ice and substrates. We observe that high interfacial energy restricts ice mobility and increases both ice detaching and shearing stresses. We quantify up to a 60% decrease in ice adhesion strength by an aqueous water layer, and provide atomistic details that support previous experimental studies. Our results contribute quantitative comparison of nanoscale adhesion strength of ice on hydrophobic and hydrophilic surfaces, and supply for the first time theoretical references for understanding the mechanics at the atomistic origins of macroscale ice adhesion.

  12. A Robust Epoxy Resins @ Stearic Acid-Mg(OH)2 Micronanosheet Superhydrophobic Omnipotent Protective Coating for Real-Life Applications.

    Science.gov (United States)

    Si, Yifan; Guo, Zhiguang; Liu, Weimin

    2016-06-29

    Superhydrophobic coating has extremely high application value and practicability. However, some difficult problems such as weak mechanical strength, the need for expensive toxic reagents, and a complex preparation process are all hard to avoid, and these problems have impeded the superhydrophobic coating's real-life application for a long time. Here, we demonstrate one kind of omnipotent epoxy resins @ stearic acid-Mg(OH)2 superhydrophobic coating via a simple antideposition route and one-step superhydrophobization process. The whole preparation process is facile, and expensive toxic reagents needed. This omnipotent coating can be applied on any solid substrate with great waterproof ability, excellent mechanical stability, and chemical durability, which can be stored in a realistic environment for more than 1 month. More significantly, this superhydrophobic coating also has four protective abilities, antifouling, anticorrosion, anti-icing, and flame-retardancy, to cope with a variety of possible extreme natural environments. Therefore, this omnipotent epoxy resins @ stearic acid-Mg(OH)2 superhydrophobic coating not only satisfies real-life need but also has great application potential in many respects.

  13. Civil Aircraft Operate in Cold Weather%民航飞机在寒冷天气下的运行

    Institute of Scientific and Technical Information of China (English)

    韩军

    2014-01-01

    寒冷天气对民航运行的威胁与危害是不容忽视的。该文就如何在寒冷天气下运行,进行了详细的分析与论述。首先提出了机场的保障能力和法规有待完善。然后阐述了飞机在寒冷天气下除冰,防冰的原因及原理。最后列出了机组在寒冷天气下运行需要注意的重要事项。%Threats and hazards of cold weather for civil aviation operation can not be ignored. This article on how to run in cold weather, carry out a detailed analysis and discussion. First proposed the airport security capabilities and regulations need to be im-proved. And then expounds the reason and principle of the aircraft deicing and anti-icing in cold weather. Finally, lists the impor-tant matters for the flight crew ,which need to be attention during operation in cold weather.

  14. Investigation and Analysis of Ice and Snow Disaster Suffered by Hunan Power Grid in 2008

    Institute of Scientific and Technical Information of China (English)

    Zhang Wenliang; Zhao Donglai; Zuo Songlin; Fu Zhiyang; Qu Qiang; Yu Yongqing; Su Zhiyi; Fan Jianbin; Li Peng; Yuan Dalu; Wu Shouyuan; Song Gao; Deng Zhanfeng

    2008-01-01

    @@ In January 2008,a sudden disaster caused by icing and snowing happened in large areas of Central China and South China.The equipments of Hunan power grid were seriously damaged during the icing and snowing disaster.An expert group from China Electric Power Research Institute (CEPRI) was organized and went to Hunan province for field investigation.As a summary of this investigation,this paper introduces power equipment damages,such as flashover caused by icing,collapse of towers,conductor breakage and damage of substation equipments.The countermeasures adopted for this icing and snowing disaster are also summarized.The analysis shows that the rare meteorological condition is the main reason for large-area damage of Hunan power grid.In the icing disaster of Hunan power grid,the ice thickness greatly exceeds the permissible limit of design,thus it is necessary to improve the design parameters reasonably to against icing of transmission lines,and the design of external insulation and the anti-icing technology for substations are also need to be enhanced.

  15. Controlled growth of standing Ag nanorod arrays on bare Si substrate using glancing angle deposition for self-cleaning applications

    Science.gov (United States)

    Singh, Dhruv P.; Singh, J. P.

    2014-03-01

    A facile approach to manipulate the hydrophobicity of surface by controlled growth of standing Ag nanorod arrays is presented. Instead of following the complicated conventional method of the template-assisted growth, the morphology or particularly average diameter and number density (nanorods cm-2) of nanorods were controlled on bare Si substrate by simply varying the deposition rate during glancing angle deposition. The contact angle measurements showed that the evolution of Ag nanorods reduces the surface energy and makes an increment in the apparent water contact angle compared to the plain Ag thin film. The contact angle was found to increase for the Ag nanorod samples grown at lower deposition rates. Interestingly, the morphology of the nanorod arrays grown at very low deposition rate (1.2 Å sec-1) results in a self-cleaning superhydrophobic surface of contact angle about 157° and a small roll-off angle about 5°. The observed improvement in hydrophobicity with change in the morphology of nanorod arrays is explained as the effect of reduction in solid fraction within the framework of Cassie-Baxter model. These self-cleaning Ag nanorod arrays could have a significant impact in wide range of applications such as anti-icing coatings, sensors and solar panels.

  16. Bioinspired, roughness-induced, water and oil super-philic and super-phobic coatings prepared by adaptable layer-by-layer technique

    Science.gov (United States)

    Brown, Philip S.; Bhushan, Bharat

    2015-01-01

    Coatings with specific surface wetting properties are of interest for anti-fouling, anti-fogging, anti-icing, self-cleaning, anti-smudge, and oil-water separation applications. Many previous bioinspired surfaces are of limited use due to a lack of mechanical durability. Here, a layer-by-layer technique is utilized to create coatings with four combinations of water and oil repellency and affinity. An adapted layer-by-layer approach is tailored to yield specific surface properties, resulting in a durable, functional coating. This technique provides necessary flexibility to improve substrate adhesion combined with desirable surface chemistry. Polyelectrolyte binder, SiO2 nanoparticles, and silane or fluorosurfactant layers are deposited, combining surface roughness and necessary chemistry to result in four different coatings: superhydrophilic/superoleophilic, superhydrophobic/superoleophilic, superhydrophobic/superoleophobic, and superhydrophilic/superoleophobic. The superoleophobic coatings display hexadecane contact angles >150° with tilt angles 160° with tilt angles oleophobic and hydrophobic properties, whilst others mix and match oil and water repellency and affinity. Coating durability was examined through the use of micro/macrowear experiments. These coatings display transparency acceptable for some applications. Fabrication via this novel combination of techniques results in durable, functional coatings displaying improved performance compared to existing work where either durability or functionality is compromised. PMID:26353971

  17. 110kV复合绝缘子串交流冰闪特性的比较%Comparison of AC Icing Flashover Performance of 110 kV Composite Insulators

    Institute of Scientific and Technical Information of China (English)

    蒋兴良; 董冰冰

    2012-01-01

    The electrical insulation strength of existing composite insulators would reduce with the shed configuration which is easier to be bridged by the ice in icing regions. Icing flashover of insulator strings can lead to power outages, even worse, threatens the safe operation of power networks at normal service voltage. Based on the icing characteristics of four types of 110kV composite insulators in the multi-function artificial climate chamber, the icing influence, icing flashover influence and flashover process were investigated and compared. The results show that the characteristic exponents a (characterizing the influence of pollution degree ESDD on the flashover voltage Uf) of the 110kV anti-icing composite insulators are smaller than that of the normal composite insulator in the same icing conditions. Moreover, the percentage of voltage increases between the former and latter increases with the increase of the pollution degree ESdd-Namely, the pollution is more serious, the flashover voltage of anti-icing composite insulators is higher than normal. So the reasonable composite insulator's umbrella structure can improve the icing flashover performance. The results can offer some consult for the selection and design of composite insulator used transmission lines in the icing regions.%覆冰地区现有的复合绝缘子的伞形结构较易被冰凌桥接,使其电气绝缘性能下降,在运行电压下发生冰闪导致停电,严重时将威胁电网的安全运行.基于多功能人工气候室内4种结构的110kV复合绝缘子串的覆冰特征,比较研究了它们的覆冰特性、冰闪特性和闪络过程的影响.结果表明:相同覆冰条件下,110kV防冰闪型复合绝缘子的特征指数a(表征污秽程度ESDD对冰闪电压Uf影响的特征指数)小于普通型复合绝缘子串,其冰闪电压比普通型绝缘子提高的百分比随着染污盐密的增加而增大,即污秽程度越重,防冰型复合绝缘子的冰闪电压比普通型

  18. Influence of Superhydrophobic Properties on Deicing

    Science.gov (United States)

    Nazhipkyzy, M.; Mansurov, Z. A.; Amirfazli, A.; Esbosin, A.; Temirgaliyeva, T. S.; Lesbayev, B. T.; Aliyev, E. T.; Prikhodko, N. G.

    2016-11-01

    Nowadays the creation of anti-icing, or deicing, surfaces is one of the most important problems, as such surfaces are widely used in aeronautics, wind turbines, and telecommunication antennas. In this paper, we focus mainly on reducing the ice adhesion forces and easy ice removal, once ice has formed. Removal of a liquid from a surface can be provided by modification of the surface wettability by means of applying superhydrophobic coatings. Such coatings are water-resistant, i.e., are characterized by low water adhesion forces. To study the impact of superhydrophobic coatings, tests were performed on the surface of a wing in a wind tunnel. By spraying Teflon and polyphenylene sulfide (PPS) on the wing, we obtained a superhydrophobic film. This film has a structure that provides superhydrophobic properties, so that the wetting angle is above 140°. A comparison of the resulting surface with a clean Teflon one shows that adhesion of the Teflon + PPS mixture to an aluminum surface is five times higher. We also investigate the degree of ice formation on the surfaces of simple and superhydrophobic aircraft wings at a temperature of -18°C. It was shown that ice was formed on a simple wing within 40 s and on a superhydrophobic wing within 25 s. When the simple wing with a mass of 23 g was inserted into the wind tunnel, its mass reached 50 g, and for a superhydrophobic wing with a mass of 26 g the latter reached 42 g. The sample of the airfoil wing we prepared has a low adhesion, which helps in easy ice removal.

  19. 飞行结冰后复杂系统动力学仿真与风险评估%Dynamic Simulation Study of Stalling in Wing Icing Conditions and Risk Evaluation

    Institute of Scientific and Technical Information of China (English)

    刘东亮; 徐浩军; 李嘉林; 薛源

    2011-01-01

    综合考虑结冰后气动参数的变化和驾驶员动态特性,建立了结冰后人-机-环复杂系统非线性动力学仿真模型,仿真出结冰后迎角、俯仰角和俯仰角速度的变化趋势。提出了结冰恶化速率因子的概念,以迎角为临界参数,提出了通过冰型、结冰强度来判断失速的方法,提出了综合评估飞机在某一航段结冰后飞行风险的思路和对防冰系统最大允许故障率进行计算的方法,最后给出算例验证了该方法的实用性。%Considering the change of aerodynamic parameters after icing and dynamic characters of pilot,the model of iced pilot-aircraft-environment nonlinear dynamical complex simulation system was built up,and then the simulation of the change of angle of attack,pitch angle,pitch rate along with time was completed.The concept of icing deterioration velocity factor was proposed.Using angle of attack as critical parameter,a method for judging stalling based on the type and velocity of incrassation of icing was brought forward.A thought for evaluating the flighting risk caused by icing in a given route and a calculating method of the highest permitted failure rate of anti-icing system were proposed.Finally,an example was given to validate the method's practicability.

  20. An easy and environmentally-friendly approach to superamphiphobicity of aluminum surfaces

    Science.gov (United States)

    Deng, R.; Hu, Y. M.; Wang, L.; Li, Zh. H.; Shen, T.; Zhu, Y.; Xiang, J. Zh.

    2017-04-01

    Superamphiphobic Al surfaces were achieved via an easy and environmentally-friendly approach. Aqueous mixed solution of 0.7 M CuSO4 and 1 M NaCl was used to etch polished Al surfaces to fabricate a rough morphology distributed with microscale step-like pits. The uniformly distributed nanoscale petals covered on the microscale pits were obtained by subsequent 96 °C hot deionized water bathing for 13 min. Thus, the hierarchical micro/nanometer scale roughness was formed which provided the structural basic of superamphiphobic Al surfaces. By 1H, 1H, 2H, 2H-Perfluorodecyl-triethoxysilane (PFDTS) derivatization, desirable superamphiphobic Al surfaces were achieved with the highest static contact angles of 162° for water, 156° for peanut oil, respectively. Meanwhile, the sliding angles were lower than 10° for both water and peanut oil droplets. The as-prepared Al surfaces were investigated by field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and optical contact angle measurements. The FE-SEM images of as-prepared Al surfaces showed a hierarchical micro/nanometer scale morphology. XPS analyses demonstrated the PFDTS derivitization on Al surfaces. The superamphiphobic Al surfaces presented good mechanical durability and chemical stability which have a wide range of applications in fields such as self-cleaning, anti-icing, anti-corrosion, oil transportation, energy harvesting, microfluidics, and so forth. The approach reported in this paper may easily realize the industrial production of superamphiphobic Al surfaces owing to the advantage of facile, low cost and environmentally-friendly.

  1. Problems in creation of modern air inlet filters of power gas turbine plants in Russia and methods of their solving

    Science.gov (United States)

    Mikhaylov, V. E.; Khomenok, L. A.; Sherapov, V. V.

    2016-08-01

    The main problems in creation and operation of modern air inlet paths of gas turbine plants installed as part of combined-cycle plants in Russia are presented. It is noted that design features of air inlet filters shall be formed at the stage of the technical assignment not only considering the requirements of gas turbine plant manufacturer but also climatic conditions, local atmospheric air dustiness, and a number of other factors. The recommendations on completing of filtration system for air inlet filter of power gas turbine plants depending on the facility location are given, specific defects in design and experience in operation of imported air inlet paths are analyzed, and influence of cycle air preparation quality for gas turbine plant on value of operating expenses and cost of repair works is noted. Air treatment equipment of various manufacturers, influence of aerodynamic characteristics on operation of air inlet filters, features of filtration system operation, anti-icing system, weather canopies, and other elements of air inlet paths are considered. It is shown that nonuniformity of air flow velocity fields in clean air chamber has a negative effect on capacity and aerodynamic resistance of air inlet filter. Besides, the necessity in installation of a sufficient number of differential pressure transmitters allowing controlling state of each treatment stage not being limited to one measurement of total differential pressure in the filtration system is noted in the article. According to the results of the analysis trends and methods for modernization of available equipment for air inlet path, the importance of creation and implementation of new technologies for manufacturing of filtering elements on sites of Russia within the limits of import substitution are given, and measures on reliability improvement and energy efficiency for air inlet filter are considered.

  2. Electric-field-enhanced condensation on superhydrophobic nanostructured surfaces.

    Science.gov (United States)

    Miljkovic, Nenad; Preston, Daniel J; Enright, Ryan; Wang, Evelyn N

    2013-12-23

    When condensed droplets coalesce on a superhydrophobic nanostructured surface, the resulting droplet can jump due to the conversion of excess surface energy into kinetic energy. This phenomenon has been shown to enhance condensation heat transfer by up to 30% compared to state-of-the-art dropwise condensing surfaces. However, after the droplets jump away from the surface, the existence of the vapor flow toward the condensing surface increases the drag on the jumping droplets, which can lead to complete droplet reversal and return to the surface. This effect limits the possible heat transfer enhancement because larger droplets form upon droplet return to the surface, which impedes heat transfer until they can be either removed by jumping again or finally shedding via gravity. By characterizing individual droplet trajectories during condensation on superhydrophobic nanostructured copper oxide (CuO) surfaces, we show that this vapor flow entrainment dominates droplet motion for droplets smaller than R ≈ 30 μm at moderate heat fluxes (q″ > 2 W/cm(2)). Subsequently, we demonstrate electric-field-enhanced condensation, whereby an externally applied electric field prevents jumping droplet return. This concept leverages our recent insight that these droplets gain a net positive charge due to charge separation of the electric double layer at the hydrophobic coating. As a result, with scalable superhydrophobic CuO surfaces, we experimentally demonstrated a 50% higher overall condensation heat transfer coefficient compared to that on a jumping-droplet surface with no applied field for low supersaturations (condensation heat transfer enhancement but also offers avenues for improving the performance of self-cleaning and anti-icing surfaces as well as thermal diodes.

  3. High-Speed Imaging of a Water Droplet Impacting a Super Cold Surface

    KAUST Repository

    Khaled, Narimane

    2016-08-01

    Frost formation is of a major research interest as it can affect many industrial processes. Frost appears as a thin deposit of ice crystals when the temperature of the surface is below the freezing point of the liquid. The objective of this research is to study icing with hope to propose new anti-icing and deicing methods. In the beginning of the research, cracking of the ice layer was observed when a deionized water droplet impacts a ?50 oC cooled sphere surface that is in contact with dry ice. To further investigate the cracks occurrence, multiple experiments were conducted. It was observed that the sphere surface temperature and droplet temperature (ranges from 10-80 oC) have no effect on the crack formation. On the other hand, it was observed that formation of a thin layer of frost on the sphere before the drop impact leads the lateral cracking of the ice. Thus, attempts to reproduce the cracks on clean super cold sphere surfaces were made using scratched and sandblasted spheres as well as superhydrophobized and polymer particle coated spheres. Furthermore, innovative methods were tried to initiate the cracks by placing epoxy glue bumps and ice-islands coatings on the surface of the spheres. All of these attempts to reproduce the crack formation without the presence of frost, failed. Nonetheless, the adding of isolated frost on the sphere surfaces always leads to the crack formation. Generally, frost forms on the small spheres faster than it does on the bigger ones. Additionally, the cold water droplet produces thicker water and ice layer compared to a hot water droplet; and the smaller the sphere the larger its water and ice layer thicknesses.

  4. Spinoff 2012

    Science.gov (United States)

    2013-01-01

    Topics covered include: Water Treatment Technologies Inspire Healthy Beverages; Dietary Formulas Fortify Antioxidant Supplements; Rovers Pave the Way for Hospital Robots; Dry Electrodes Facilitate Remote Health Monitoring; Telescope Innovations Improve Speed, Accuracy of Eye Surgery; Superconductors Enable Lower Cost MRI Systems; Anti-Icing Formulas Prevent Train Delays; Shuttle Repair Tools Automate Vehicle Maintenance; Pressure-Sensitive Paints Advance Rotorcraft Design Testing; Speech Recognition Interfaces Improve Flight Safety; Polymers Advance Heat Management Materials for Vehicles; Wireless Sensors Pinpoint Rotorcraft Troubles; Ultrasonic Detectors Safely Identify Dangerous, Costly Leaks; Detectors Ensure Function, Safety of Aircraft Wiring; Emergency Systems Save Tens of Thousands of Lives; Oxygen Assessments Ensure Safer Medical Devices; Collaborative Platforms Aid Emergency Decision Making; Space-Inspired Trailers Encourage Exploration on Earth; Ultra-Thin Coatings Beautify Art; Spacesuit Materials Add Comfort to Undergarments; Gigapixel Images Connect Sports Teams with Fans; Satellite Maps Deliver More Realistic Gaming; Elemental Scanning Devices Authenticate Works of Art; Microradiometers Reveal Ocean Health, Climate Change; Sensors Enable Plants to Text Message Farmers; Efficient Cells Cut the Cost of Solar Power; Shuttle Topography Data Inform Solar Power Analysis; Photocatalytic Solutions Create Self-Cleaning Surfaces; Concentrators Enhance Solar Power Systems; Innovative Coatings Potentially Lower Facility Maintenance Costs; Simulation Packages Expand Aircraft Design Options; Web Solutions Inspire Cloud Computing Software; Behavior Prediction Tools Strengthen Nanoelectronics; Power Converters Secure Electronics in Harsh Environments; Diagnostics Tools Identify Faults Prior to Failure; Archiving Innovations Preserve Essential Historical Records; Meter Designs Reduce Operation Costs for Industry; Commercial Platforms Allow Affordable Space Research

  5. Wetting hysteresis induced by temperature changes: Supercooled water on hydrophobic surfaces.

    Science.gov (United States)

    Heydari, Golrokh; Sedighi Moghaddam, Maziar; Tuominen, Mikko; Fielden, Matthew; Haapanen, Janne; Mäkelä, Jyrki M; Claesson, Per M

    2016-04-15

    The state and stability of supercooled water on (super)hydrophobic surfaces is crucial for low temperature applications and it will affect anti-icing and de-icing properties. Surface characteristics such as topography and chemistry are expected to affect wetting hysteresis during temperature cycling experiments, and also the freezing delay of supercooled water. We utilized stochastically rough wood surfaces that were further modified to render them hydrophobic or superhydrophobic. Liquid flame spraying (LFS) was utilized to create a multi-scale roughness by depositing titanium dioxide nanoparticles. The coating was subsequently made non-polar by applying a thin plasma polymer layer. As flat reference samples modified silica surfaces with similar chemistries were utilized. With these substrates we test the hypothesis that superhydrophobic surfaces also should retard ice formation. Wetting hysteresis was evaluated using contact angle measurements during a freeze-thaw cycle from room temperature to freezing occurrence at -7°C, and then back to room temperature. Further, the delay in freezing of supercooled water droplets was studied at temperatures of -4°C and -7°C. The hysteresis in contact angle observed during a cooling-heating cycle is found to be small on flat hydrophobic surfaces. However, significant changes in contact angles during a cooling-heating cycle are observed on the rough surfaces, with a higher contact angle observed on cooling compared to during the subsequent heating. Condensation and subsequent frost formation at sub-zero temperatures induce the hysteresis. The freezing delay data show that the flat surface is more efficient in enhancing the freezing delay than the rougher surfaces, which can be rationalized considering heterogeneous nucleation theory. Thus, our data suggests that molecular flat surfaces, rather than rough superhydrophobic surfaces, are beneficial for retarding ice formation under conditions that allow condensation and frost

  6. Evaluation Analysis of First DC-Based Deicing Device in Northwest China%西北首套直流融冰装置工程启动评价分析

    Institute of Scientific and Technical Information of China (English)

    刘巍; 崔力心; 郭文科; 陈仕彬; 郝如海; 倪赛赛

    2016-01-01

    甘肃陇南地区直流融冰装置的建成投运,极大地增强了该地区线路抗覆冰能力。应用Matlab软件对330 kV晒都线路搭建仿真模型进行仿真分析和现场电能质量测试结果验证;同时在现场启动过程中,对整流变空载投切,线路重合闸后加速保护误动原因分析,并给出了解决涌流跳闸措施,有效减少了变电站整流变装置开关跳闸次数,缩短了停电时间,提高了晒都线供电可靠性。%DC-based deicing devices which were put into operation in Longnan of Gansu province greatly enhanced the anti-icing capability in the area. The software Matlab was used to carry out simulation analysis for the model of 330kV Shaidu lines and to verify the test results of the current power quality. Meanwhile, the rectiifer was unloaded, the electric brake was turned on in the process of starting the equipment and the reason of protection mal-operation was analyzed rapidly. This paper gave the measures of lfashy lfow tripping operation, which effectively reduced the number of tripping of the switch in the transformer substation, shortened the outage time and improved the reliability of power sup-ply.

  7. EXPERIMENTAL STUDIES ON DEVELOPMENT OF SUSTAINABLE AGRICULTURAL-BASED ROAD TRANSPORT DEICING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Peter C. Taylor

    2014-06-01

    Full Text Available Snow and ice removal on highways and public streets is critical for safe operation of the road transportation infrastructure. The issues to be addressed in selecting suitable deicing and anti-icing materials include cost, effectiveness, and damage to the pavement, vehicles and the environment. Considerable research has been carried out in recent years to develop alternative deicers with better performance and cost effectiveness. Among the developed deicer materials are agricultural based deicers that are considered to be sustainable and environmentally-beneficial materials. Iowa is one of the States that is rich in agricultural renewable resources, some of which are being processed for applications such as fuel. Any industrial process, including that of converting corn to ethanol or soy to bio-diesel, is likely to have a number of by-products generated. Rather than face disposal issues for these by-products, it would be desirable to find those that, with a minimum of additional processing, can be used as a deicing compound, either alone, or in combination with products currently in use. Currently, a number of agricultural based deicer materials have been developed or are still under development. However, little information is known about the actual manufacturing/refining process since most of the developed materials are all proprietary products (patented or commercial. Furthermore, no standard test specifying agricultural-based deicer is available. The study described in this paper focuses on the development of an improved agricultural based deicing product. The objective of this study was to evaluate deicer materials including traditional and alternative deicer materials on road skid resistance which is critical for safe operation of the road transportation infrastructure.

  8. Initial development of high-accuracy CFRP panel for DATE5 antenna

    Science.gov (United States)

    Qian, Yuan; Lou, Zheng; Hao, Xufeng; Zhu, Jing; Cheng, Jingquan; Wang, Hairen; Zuo, Yingxi; Yang, Ji

    2016-07-01

    DATE5 antenna, which is a 5m telescope for terahertz exploration, will be sited at Dome A, Antarctica. It is necessary to keep high surface accuracy of the primary reflector panels so that high observing efficiency can be achieved. In antenna field, carbon fiber reinforced composite (CFRP) sandwich panels are widely used as these panels are light in weight, high in strength, low in thermal expansion, and cheap in mass fabrication. In DATE5 project, CFRP panels are important panel candidates. In the design study phase, a CFRP prototype panel of 1-meter size is initially developed for the verification purpose. This paper introduces the material arrangement in the sandwich panel, measured performance of this testing sandwich structure samples, and together with the panel forming process. For anti-icing in the South Pole region, a special CFRP heating film is embedded in the front skin of sandwich panel. The properties of some types of basic building materials are tested. Base on the results, the deformation of prototype panel with different sandwich structures and skin layers are simulated and a best structural concept is selected. The panel mold used is a high accuracy one with a surface rms error of 1.4 μm. Prototype panels are replicated from the mold. Room temperature curing resin is used to reduce the thermal deformation in the resin transfer process. In the curing, vacuum negative pressure technology is also used to increase the volume content of carbon fiber. After the measurement of the three coordinate measure machine (CMM), a prototype CFRP panel of 5.1 μm rms surface error is developed initially.

  9. Biomimetic Multi-Functional Superamphiphobic FOTS-TiO2 Particles beyond Lotus Leaf.

    Science.gov (United States)

    Chen, Liwei; Guo, Zhiguang; Liu, Weimin

    2016-10-12

    It is widely known that natural examples like lotus leaves can only repel room-temperature water but cannot repel hot water and oils. Even though superamphiphobic surfaces composed of re-entrant "mushroom-like" or "T-shaped" structures are promising, they are generally regarded as substrate-dependent and difficult to fabricate, and hence, their practical use on various materials has been limited. Here, we synthesize a flower-like superamphiphobic FOTS-TiO2 powder by solvothermal process and self-assembly functionalization. These structured and functionalized submicron particles can repel the liquids with surface tension as low as 23.8 mN·m(-1) (n-decane), which is the lowest among powder samples. With respect to the biomimetic aspect, the surface morphology of FOTS-TiO2 particle is similar to the hierarchical micro/nano-structures of the lotus leaf surface, but it is beyond the lotus leaf for superoleophobic capacity. The difference in the oleophobicity is suggested to be the interplay of quasi-spherical re-entrant structure and perfluorined modification. Because of superior superamphiphobicity of the powder, a facile yet versatile strategy is developed, adhesive-assisted sieve deposition fabrication (AASDF), for preparing superamphiphobic coatings on various substrates. The investigation results pertaining to the water/oil proofing, mechanical durability, self-cleaning, and antifouling performances prove that the FOTS-TiO2 coating is robust and multifunctional, which will enable more opportunities for practical applications. Apart from these general applications, we find that the superamphiphobic FOTS-TiO2 powders when coated on sponge as anti-icing surface have good ice delay and icephobic performances. Furthermore, they can be used to prepare magnetic Fe3O4&FOTS-TiO2 composite particles through liquid marbles, implying significant scientific value.

  10. Shear shedding of drops and the use of superhydrophobic surfaces in microgravity: PFC and ground based results

    Science.gov (United States)

    Milne, Andrew; Amirfazli, Alidad

    In free fall, the absence of gravity poses many challenges for fluid handling systems. One such example of this is condensers. On earth, the condensed liquid is removed from the tilted condenser plate by gravity forced shedding. In microgravity, proposed solutions include the use of surfaces with gradients in wettability [1], the use of electrowetting [2], and shearing airflow [3]. In this talk, shear shedding results for a variety of surface (hydrophilic to superhydrophobic (extremely water repelling)) will be presented. Surface science and aerodynamics are used to reveal fundamental parameters controlling incipient motion for drops exposed to shearing airflow. It is found that wetting parameters such as contact angle and surface tension are very influential in determining the minimum required air velocity for drop shedding. Based on experimental results for drops of water and hexadecane (0.5-100 l) on PMMA, Teflon, and a superhydrophobic aluminum surface, an exponential function is proposed that relates the critical air velocity for shedding to the ratio of drop base length to projected area. The results for the water systems can be collapsed to a self similar curve by normalization, which also explains results from other researchers. Since shedding from superhydrophobic surfaces (SHS) is seen to be easier compared to other surfaces, the behaviour of SHS is also probed in this talk. SHS have space-based applications to shedding, self cleaning, anti-icing (spacecraft launch/re-entry), anti-fouling, fluid actuation, and decreased fluid friction. The mechanism for SHS is understood to be the existence of an air layer between large portions of the drop and solid. The first concrete visual evidence of this was gained performing a parabolic flight experiment with the ESA. Results of this experi-ment will be discussed, showing the extreme water repelling potential of SHS in microgravity, and demonstrating how the wetting behaviours seen (partial penetration, transition

  11. 有机无机杂化丙烯酸乳液的制备及涂膜性质研究%Preparation of Organic and Inorganic Hybrid Acrylic Emulsion and Properties of Its Films

    Institute of Scientific and Technical Information of China (English)

    刘芳; 黄伟

    2011-01-01

    为了制备一种疏水抗覆冰涂料,采用种子半连续乳液聚合法,通过添加乙烯基三乙氧基硅烷(A-151)和纳米二氧化硅粉末,分别合成了纯丙乳液、硅丙乳液和纳米二氧化硅/硅丙复合乳液,并将乳液涂覆在铝片表面,室温干燥成膜.利用红外光谱、粒度分析、扫描电镜等测试手段对3种乳液及其涂膜性能进行表征.结果表明:添加A-151可以使涂膜交联度提高到95%,吸水率降低到5%;添加纳米二氧化硅,可提高乳液涂膜的热分解温度,使乳液粒径大小分布均匀.此方法中,A-151和纳米二氧化硅改性的乳液涂膜疏水作用有限,仅使接触角增加到约30°.%A hydrophobic anti -icing coating was prepared with pure acrylic emulsion, silicon -acrylate emulsion and nano - silica/silicone - acrylate composite emulsion respectively, which were prepared by the semi - continuous emulsion polymerization process, with addition of vinyl triethoxye silane (A - 151) and nauosilica powder. Films were prepared these emulsion applied on the surface of aluminum sheet separately and dried at room temperature. The structure of these three kind of emulsions and films were charactered by FT-IR, particle size analysis and SEM. The results showed that addition of A - 151 can increase the crosslinking degree of film to 95% , while the water absorbability reduced to 5%. The thermal decomposition temperatures of these films went higher by using nano - silica. Nano - silica was also helpful for the uniform distribution of diameter of emulsions' particles. The contact angle of the films of silicone - acrylate emulsion and nano - silica/silicone - acrylate composite emulsion was increased slightly to 30°.

  12. Calculation of Hunan Power Grid Icing Recurrence Interval Based on Extreme-value Type Ⅰ Probability Distribution Model%基于极值Ⅰ型概率分布模型的湖南地区电网覆冰重现期计算

    Institute of Scientific and Technical Information of China (English)

    陆佳政; 张红先; 彭继文; 方针; 李波

    2012-01-01

    分析电网覆冰重现期,对于掌握冰灾规律从而指导抗冰工作具有重要指导意义。为此,提出了基于极值I型分布的电网覆冰重现期计算方法,结合97个气象站1951-2008年的覆冰日数观测数据,计算了97个气象站点15a一遇、30a一遇、50a一遇和100a一遇冰灾的覆冰日数,计算结果显示,长沙马坡岭气象站100a一遇的覆冰日数为14.78d。按照特别严重覆冰重现期为11d以上的划分标准,在极值Ⅰ型计算模型下,湖南电网特别严重覆冰重现期为24.8a。根据计算结果,绘制了湖南省多年一遇覆冰分布图,该图显示,湖南的覆冰严重区域集中在湘西南和湘东南地区。覆冰分布图为今后电网抗冰设计工作提供了指导。%It is very important to analyze icing recurrence interval of power grid for understanding ice disaster law and guiding ice-resistant.We put forward a calculation method of icing recurrence interval of power grid based on extreme-value type I,and calculated the icing days for recurrence period of 15 years,30 years,50 years and 100 years from 97 weather stations with the observation data of icing days from 1951 to 2008.The results show that the number of icing day for recurrence period of 100 years in Changsha Mapoling weather station is 14.78.If standard of serious icing of over 11 days is adopted,recurrence period of serious icing is 24.8 years in this model.Consequently,an icing distribution map of recurrence period of multi-years is plotted for design of anti-icing of power grid,showing that areas of serious icing are southwest and southeast of Hunan.

  13. Magnetocaloric effect of FeCrB amorphous alloys with low Curie point%低居里点FeCrB非晶合金的磁热效应

    Institute of Scientific and Technical Information of China (English)

    高学绪; 包小倩; 贺永芳

    2012-01-01

    Fe100-x-yCrxBy(x = 11-20, y = 9 -20) amorphous ribbons with low Curie point and high saturation magnetization, which could be applied in anti-icing in transmission lines, were prepared by rapid-quenching with various technological parameters. Experimental results show that the Curie temperatures of Fe65Cr15B20 and Fe64Cr16B20 amorphous ribbons are 28.6 and 11.6 ℃ , while the saturation magnetizations of Fe65 Cr15 B20 and Fe64 Crl6 B2o amorphous ribbons are 0.69 and 0.62 T at 0 ℃ , respectively. Magnetocaloric effects of Fe65 Cr15 B20 and Fe64 Crl6 B20 amorphous ribbons were approximately measured and analyzed by using a self-designed apparatus on the basis of the near heat-insulation method.%基于输电线路抗覆冰的应用背景,通过对Fe100-x-yCrsBy(x=11~20,y=9-20)的成分调节和快淬工艺参数控制,制备了同时具有低居里温度和高饱和磁极化强度的非晶带材.测试研究表明Fe65Cr15B20和Fe64Cr16B20的居里温度分别为28.6和11.6℃,Fe65Cr15B20和Fe64cr16B20在0℃的饱和磁极化强度分别为0.69和0.62T.设计组装了一种近似绝热磁致热功率的测量装置,用该装置对Fe65cr15B20和Fe64cr16B20两种非晶合金带的磁热功率进行了近似测量和分析.

  14. Geochemistry of groundwater in the Beaver and Camas Creek drainage basins, eastern Idaho

    Science.gov (United States)

    Rattray, Gordon W.; Ginsbach, Michael L.

    2014-01-01

    The U.S. Geological Survey (USGS), in cooperation with the U.S. Department of Energy, is studying the fate and transport of waste solutes in the eastern Snake River Plain (ESRP) aquifer at the Idaho National Laboratory (INL) in eastern Idaho. This effort requires an understanding of the natural and anthropogenic geochemistry of groundwater at the INL and of the important physical and chemical processes controlling the geochemistry. In this study, the USGS applied geochemical modeling to investigate the geochemistry of groundwater in the Beaver and Camas Creek drainage basins, which provide groundwater recharge to the ESRP aquifer underlying the northeastern part of the INL. Data used in this study include petrology and mineralogy from 2 sediment and 3 rock samples, and water-quality analyses from 4 surface-water and 18 groundwater samples. The mineralogy of the sediment and rock samples was analyzed with X-ray diffraction, and the mineralogy and petrology of the rock samples were examined in thin sections. The water samples were analyzed for field parameters, major ions, silica, nutrients, dissolved organic carbon, trace elements, tritium, and the stable isotope ratios of hydrogen, oxygen, carbon, sulfur, and nitrogen. Groundwater geochemistry was influenced by reactions with rocks of the geologic terranes—carbonate rocks, rhyolite, basalt, evaporite deposits, and sediment comprised of all of these rocks. Agricultural practices near and south of Dubois and application of road anti-icing liquids on U.S. Interstate Highway 15 were likely sources of nitrate, chloride, calcium, and magnesium to groundwater. Groundwater geochemistry was successfully modeled in the alluvial aquifer in Camas Meadows and the ESRP fractured basalt aquifer using the geochemical modeling code PHREEQC. The primary geochemical processes appear to be precipitation or dissolution of calcite and dissolution of silicate minerals. Dissolution of evaporite minerals, associated with Pleistocene Lake

  15. Ground Freezing Fog Simulation Technology Study%开放式结冰条件模拟技术研究

    Institute of Scientific and Technical Information of China (English)

    李志茂; 李革萍; 王大伟; 沈东

    2013-01-01

    在-1~-9益的环境温度条件下,采用开放式结冰条件模拟技术可以为民机或军机发动机短舱防冰系统性能试验模拟出合适的结冰气象条件。采用气液两相喷嘴模拟水雾结冰环境时,所采用气体和液体的纯度是过冷水滴产生的先决条件,气液两相压差、风洞吹风速度和试验对象距离是影响结冰气象参数的关键因子。采用改造后的FM-100传感器可实现对结冰气象参数的实时测量。通过升降机构、小角度俯仰和万向轮等辅助结构设计,开放式结冰条件模拟系统可以满足不同试验对象的试验要求,可以适应不同风向的试验环境,具备非常广阔的推广应用前景。%Ground freezing fog simulation technology can generate icing condition for commercial or military air-craft nacelle anti-ice system performance evaluation under -1~-9℃. Purity of water and air used for fog genera-ting is the precondition, icing parameter is impacted by diff-pressure of liquid-gas, wind tunnel velocity and dis-tance between test article and test rig. Rectified FM-100 sensor can be used for icing parameter measurement, rig lift, small angle pitching and universal mechanical structure design make the fog simulation rig can satisfy the re-quirements of different test articles and wind directions.

  16. Mechanism of Nano-fluorocarbon Coating Restraining Ice Blocking in Supercooled Heat Exchanger%纳米氟碳涂层抑制过冷却器冰堵的机理

    Institute of Scientific and Technical Information of China (English)

    王虹; 何国庚; 田奇琦; 杨丽媛

    2012-01-01

    Ice slurry has been widely used in many fields because of its thermal properties, and ice-making technology has become a focus of study. Dynamic ice-making with supercooled water is one of the most promising method in making ice slurries, but the major defect of this method is that the ice blocking easily take place in the supercooled heat exchanger. Based on the theory of water crystallization and the analysis of the influence factors of ice blocking, a nano-fluorocarbon coating was used to improve the surface conditions of the supercooled heat exchanger and to restrain water from freezing. It is concluded that the nano-fluorocarbon coating will effectively restrain crystallization on the wall and improve the efficiency of the ice-making unit, which results in the decrease of ice blocking and the energy consumption. The investigation will benefit in developing and improving anti-icing techniques.%冰浆由于良好的热物特性,在许多领域得到广泛的应用,其制取方式也成为关注的焦点.过冷水动态制冰是目前最有发展前途的制取冰浆方式之一,但其主要缺陷是过冷却器易发生冰堵.在此,基于水溶液结晶的机理,从影响过冷却器冰堵的因素出发,指出纳米氟碳表面改性材料可改善表面状况,有效抑制壁面结冰,减少制冰过程中的冰堵问题,提高整个系统的制冰效率,降低能耗.纳米氟碳涂层抑制过冷却器冰堵的机理对进一步深化和开发新一代防结冰技术有一定意义.

  17. 基于云微物理参数的飞机积冰多因子预测方法%An Aircraft Icing Forecasting Method Based on Bloud Microphysical Parameters

    Institute of Scientific and Technical Information of China (English)

    何新党; 刘永寿; 苟文选; 张峰

    2012-01-01

    基于气象探测信息,准确进行飞机积冰预测并及时开启防/除冰系统是保障飞机飞行安全的重要方法.提出了一种多因子积冰预测方法,当已知飞机所在飞行云层类型、飞行高度、速度、气温、气压和露点温度时,使用提出的方法可计算得到飞行高度上的相对湿度、比湿、0℃高度上的气压、液态含水量等气象参数,用所建立的多因子积冰强度判别式可对飞机积冰的可能性及积冰强度进行预测.将方法应用于飞机积冰案例中,与美国国家大气科学中心提出的RAOB积冰预报方法进行了对比.分析结果表明,提出的方法准确有效,可为飞机积冰预测提供技术支持.%Introducing weather detect information to aircraft icing forecast and turning on Anti - icing/dei-cing system in time an important safeguard of ensuring airplane flight safety. This paper presents a multi-factor prediction method of ice forecasting. When the information of aircraft flying cloud type, altitude, speed,temperature,pressure and dew point temperature is known,the relative humidity,specific humidity , pressure of 0℃ high degree, liquid water content, and other weather parameters can be calculated as well as the icing probability and icing accretion rate during aircraft fly is predicted using the presented method. Using the proposed method into an aircraft icing cases,and compared with RAOB icing forecast methods of the NCAR. The analysis results show that the proposed method is accurate and valid. It can provide technical support for aircraft icing forecasting.

  18. Development of nanostructured coatings for protecting the surface of aluminum alloys against corrosion and ice accretion

    Science.gov (United States)

    Farhadi, Shahram

    Ice and wet snow accretion on outdoor structures is a severe challenge for cold climate countries. A variety of de-icing and anti-icing techniques have been developed so far to counter this problem. Passive approaches such as anti-icing or icephobic coatings that inhibit or retard ice accumulation on the surfaces are gaining in popularity. Metal corrosion should also be taken into account as metallic substrates are subject to corrosion problems when placed in humid or aggressive environments. Development of any ice-releasing coatings on aluminum structures, as they must be durable enough, is therefore closely related to anti-corrosive protection of that metal. Accordingly, series of experiments have been carried out to combine reduced ice adhesion and improved corrosion resistance on flat AA2024 substrates via thin films of single and double layer alkyl-terminated SAMs coatings. More precisely, alkyl-terminated aluminum substrates were prepared by depositing layer(s) of 18C-SAMs on BTSE-grafted AA2024 or mirror-polished AA2024 surfaces. This alloy is among the most widely used aluminum alloys in transportation systems (including aircraft), the military, etc. The stability of the coatings in an aggressive environment, their overall ice-repellent performance as well as their corrosion resistance was systematically studied. The stability of one-layer and two-layer coatings in different media was tested by means of CA measurements, demonstrating gradual loss of the hydrophobic property after ~1100-h-long immersion in water, associated by decrease in water CA. Surface corrosion was observed in all cases, except that the double-layer coating system provided improved anti-corrosive protection. All single layer coatings showed initial shear stress of ice detachment values of ~1.68 to 2 times lower than as-received aluminum surfaces and about ~1.22 to 1.5 times lower than those observed on mirror-polished surfaces. These values gradually increased after as many as 5 to 9

  19. Ice crystal ingestion by turbofans

    Science.gov (United States)

    Rios Pabon, Manuel A.

    proposed and built in this Thesis, called DBDAIS, with a complete description of the anti-ice cycle. Contrary to existing ice protection systems, which either heat the aircraft surfaces, or mechanically remove the accreted ice, the DBDAIS employs non-thermal plasma discharges to prevent ice accretion. A new apparatus that mimics inflight icing based on combining the liquid sprays of liquid nitrogen and water was designed and fabricated, named LNITA. The apparatus produces ice similar to glaze ice and rime ice, the two characteristic types of ice from inflight icing, at the cost of 1% of similar tests in icing wind tunnels. Nineteen experiments of the DBDAIS were performed in the LNITA. The results from the experiments point to 32 kV and 4 kHz being adequate to prevent ice accretion, with a power consumption of 1 W/cm2. This compares favorably to existing ice protection systems, which typically run at 10 W/cm2, and to the power consumption of a typical electric stove burner at maximum power, which is 5 W/cm2. To complete this Thesis, a design and development project is proposed to implement the DBDAIS in Unmanned Aircraft Systems (UAS), with the selection of standard FAA inflight icing conditions, the run of 240 LEWICE simulations, and an analysis of the run results. The computational results lead to the design of a wing boot covering the airfoil from 20% of the lower pressure surface to 4% of the upper suction surface as the optimal protection for a UAS.

  20. An efficient methpd tp simulate water drpplet trajectpry and impingement%水滴撞击特性的高效计算方法

    Institute of Scientific and Technical Information of China (English)

    周志宏; 易贤; 桂业伟; 李凤蔚

    2014-01-01

    针对拉格朗日方法计算水滴撞击特性效率低、通用性差等问题,发展了一种水滴撞击特性的高效计算方法。在求解绕流流场的基础上,结合逐级结构化管理的边界信息存储方式,采用目标扩散追踪方法对水滴所在网格单元进行快速计算,并插值得到该点处的流场信息,逐个求解水滴运动方程得到各水滴的运动轨迹,从而确定水滴撞击极限、收集系数等撞击特性参数。通过对 NACA0012翼型、GA-W(1)两段翼型和某三段翼型的计算得到不同状态下的水滴撞击特性,计算结果表明,该方法与传统方法相比具有计算效率高、结果可靠、通用性好等优点。%Ice formation on aircraft is of great safety concern because icing may lead the aircraft to a dangerous situation quickly.Numerical method for determining the trajectories of the water droplets is the base of the icing research and the design of the anti-icing system.The traditional Lagrangian method for simulating water droplet trajectory and impingement has some shortages such as lower computation efficiency and poor applicability currency in peculiar geometry.In order to overcome these shortages,an improved Lagrangian method was developed.It′s based on the calculation of the flow field around icing surface,using a method of searching extended target to calculate the droplet location and determining the insert value of flow field information at the droplet location in a grid cell,the boundary of the droplet trajectories are judged based on a manage system of boundary information with framework structure.The method can overcome theses shortages meanwhile maintaines the robustness of original method.Local droplet collection and impingement efficiency at NACA0012 and multi-element airfoils are calculated with this method in order to verify its correctness.The results show that the improved method is very efficient,reliable,and robust. Furthermore,it can

  1. Contribution a l'etude et a la conception d'une machine synchrone a flux transverse destinee au degivrage d'aeronefs en cours de vol

    Science.gov (United States)

    Boussetoua, Mohammed

    During winter, the climate in the northern region is known for its icing and freezing conditions. However, emergency services often use helicopters to reach isolated locations. The difficult situations, generally experiences in the North particularly in Quebec, may prevent rescuers to intervene. The main reason preventing such operations is the lack of a de-icing system in the small helicopter blades. The overall objective of the project is research, development, design and manufacture of a system composed of an on-board rotating low speed generator and heating elements. It consumes a part of the power supplied by the turbine through the axis of the main rotor of the small aircraft and converts it to electrical power to be used by the heating elements. This innovation will allow to fly safely everywhere throughout the year protect the lives of the users even in the worst weather conditions. Firstly, the research focuses on the identification of problems related to the use of protection systems against the hoarfrost on main rotor blades of different aircrafts during flight. In this phase, we specifically focused on the difficulties encountered by the aircraft companies using the existing and operational systems for protection against hoarfrost. Main rotor blades are difficult to protect on helicopters. Several systems were considered by the helicopter manufacturers, such as electrothermal systems, pneumatic systems or using anti-icing fluids. In the current state of technological knowledge, all helicopters that have been certified to fly in icing conditions use electrothermal systems for protection against hoarfrost on their main rotor Small helicopters addressed by this work, are forbidden to fly in icing conditions due to lack of energy source to operate these systems. The electrothermal system has been considered for this thesis work to protect the main rotor blades of small aircraft in-flight. The second part of this thesis is based on the source of power

  2. Validation Ice Crystal Icing Engine Test in the Propulsion Systems Laboratory at NASA Glenn Research Center

    Science.gov (United States)

    Oliver, Michael J.

    2014-01-01

    The Propulsion Systems Laboratory (PSL) is an existing altitude simulation jet engine test facility located at NASA Glenn Research Center in Cleveland, OH. It was modified in 2012 with the integration of an ice crystal cloud generation system. This paper documents the inaugural ice crystal cloud test in PSL--the first ever full scale, high altitude ice crystal cloud turbofan engine test to be conducted in a ground based facility. The test article was a Lycoming ALF502-R5 high bypass turbofan engine, serial number LF01. The objectives of the test were to validate the PSL ice crystal cloud calibration and engine testing methodologies by demonstrating the capability to calibrate and duplicate known flight test events that occurred on the same LF01 engine and to generate engine data to support fundamental and computational research to investigate and better understand the physics of ice crystal icing in a turbofan engine environment while duplicating known revenue service events and conducting test points while varying facility and engine parameters. During PSL calibration testing it was discovered than heated probes installed through tunnel sidewalls experienced ice buildup aft of their location due to ice crystals impinging upon them, melting and running back. Filtered city water was used in the cloud generation nozzle system to provide ice crystal nucleation sites. This resulted in mineralization forming on flow path hardware that led to a chronic degradation of performance during the month long test. Lacking internal flow path cameras, the response of thermocouples along the flow path was interpreted as ice building up. Using this interpretation, a strong correlation between total water content (TWC) and a weaker correlation between median volumetric diameter (MVD) of the ice crystal cloud and the rate of ice buildup along the instrumented flow path was identified. For this test article the engine anti-ice system was required to be turned on before ice crystal

  3. A combined road weather forecast system to prevent road ice formation in the Adige Valley (Italy)

    Science.gov (United States)

    Di Napoli, Claudia; Piazza, Andrea; Antonacci, Gianluca; Todeschini, Ilaria; Apolloni, Roberto; Pretto, Ilaria

    2016-04-01

    Road ice is a dangerous meteorological hazard to a nation's transportation system and economy. By reducing the pavement friction with vehicle tyres, ice formation on pavements increases accident risk and delays travelling times thus posing a serious threat to road users' safety and the running of economic activities. Keeping roads clear and open is therefore essential, especially in mountainous areas where ice is likely to form during the winter period. Winter road maintenance helps to restore road efficiency and security, and its benefits are up to 8 times the costs sustained for anti-icing strategies [1]. However, the optimization of maintenance costs and the reduction of the environmental damage from over-salting demand further improvements. These can be achieved by reliable road weather forecasts, and in particular by the prediction of road surface temperatures (RSTs). RST is one of the most important parameters in determining road surface conditions. It is well known from literature that ice forms on pavements in high-humidity conditions when RSTs are below 0°C. We have therefore implemented an automatic forecast system to predict critical RSTs on a test route along the Adige Valley complex terrain, in the Italian Alps. The system considers two physical models, each computing heat and energy fluxes between the road and the atmosphere. One is Reuter's radiative cooling model, which predicts RSTs at sunrise as a function of surface temperatures at sunset and the time passed since then [2]. One is METRo (Model of the Environment and Temperature of Roads), a road weather forecast software which also considers heat conduction through road material [3]. We have applied the forecast system to a network of road weather stations (road weather information system, RWIS) installed on the test route [4]. Road and atmospheric observations from RWIS have been used as initial conditions for both METRo and Reuter's model. In METRo observations have also been coupled to

  4. Experimental Investigation on Ice-Coating and Ice-Melting of Large-Section Current Carrying Conductors for UHVDC Transmission Project%特高压直流输电大截面导线带电覆冰与融冰特性试验研究

    Institute of Scientific and Technical Information of China (English)

    陆佳政; 胡建平; 方针

    2013-01-01

    flowing through the conductor; wind speed increase and rainfall increase can make the collision coefficient and the collection coefficient enlarged;fall of temperature can make the freezing coefficient enlarged and then the increase of ice-coating thickness is speeded up; in addition, the type of conductor ice-coating depends on ambient temperature. The time for ice-melting of large-sectional conductor mainly depends on the ice thickness to be melted and shortens with the increase of ice-melting current;the lower the ambient temperature and the higher the wind speed, the longer the time for ice-melting will be;the time for ice-melting linearly increases with the increase of ice-coating thickness. Results of this research are available for reference to the anti-icing and ice-melting of UHVDC transmission lines.

  5. Hydrogeology and water quality in the Snake River alluvial aquifer at Jackson Hole Airport, Jackson, Wyoming, water years 2011 and 2012

    Science.gov (United States)

    Wright, Peter R.

    2013-01-01

    -benzotriazole, and 5-methyl-1H-benzotriazole. Triazoles are anthropogenic compounds often used as an additive in deicing and anti-icing fluids as a corrosion inhibitor, and can be detected at lower laboratory reporting levels than glycols, which previously had not been detected. Two of the three triazoles measured, 4-methyl-1H-benzotriazole and 5-methyl-1H-benzotriazole, were detected at low concentrations in groundwater at 7 of the 10 wells sampled. The detection of triazole compounds in groundwater downgradient from airport operations makes it unlikely there is a natural cause for the high rates of reduction present in many airport monitor wells. It is more likely that aircraft deicers, anti-icers, or pavement deicers have seeped into the groundwater system and caused the reducing conditions.