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2015-06-15
Technical Paper
2015-01-2096
The correct prediction of ice accretion on aircraft surfaces by simulation necessitates a good prediction of friction coefficient and heat transfer coefficient. After icing process, surface roughness induces high increase of friction and heat transfer, but simple Reynolds analogy is no longer valid. An experimental campaign is conducted in order to provide a database for numerical model development in the simple configuration of a flat plate under turbulent airflow conditions. The flat plate model is placed in the centre of the test section of a windtunnel with an improved temperature regulation. The test model is designed according to constraints for the identification of friction and heat transfer coefficients. It includes three identical resin plates which are moulded to obtain a specified roughness on the upper surface exposed to the flow. The latest resin plate is heated on its lower face by an electrical heater connected to a temperature regulator.
2015-06-15
Technical Paper
2015-01-2105
Darren Glenn Jackson
Aircraft icing has been a focus of the aviation industry for many years. While regulations existed for the certification of aircraft and engine ice protection systems, no FAA or EASA regulations pertaining to certification of ice detection systems existed for much of this time. Interim policy on ice detection systems has been issued through the form of AC20-73A as well as FAA Issue Papers and EASA Certification Review Items to deal mainly with Primary Ice Detection Systems. A few years ago, the FAA released an update to FAR 25.1419 which provided the framework for the usage of ice detection systems on aircraft. As a result of the ATR-72 crash in Roselawn, Indiana due to Supercooled Large Droplets (SLD) along with the Air France Flight 447 accident and numerous engine flame-outs due to ice crystals, both the FAA and EASA have developed new regulations to address these concerns.
2015-06-15
Technical Paper
2015-01-2154
Franck Hervy, Severine Maguis, François Virion, Biagio Esposito, Hugo Pervier
In 2010, DGA Aero-engine Testing decided to develop a capability to reproduce glaciated icing conditions in one of its altitude test facilities able to simulate low temperature and high altitude conditions. The facility selected for this purpose, named A06, originally developed for relight and flame out testing of combustors has been modified to integrate a small experimental test cell instead of a combustor. A specific converging nozzle has been implemented to reach Mach number up to 0.85 allowing tests in free jet configuration on small test articles like probes. In addition, for ice crystals generation, spray bars have been inserted upstream the test cell. Tests have been performed to define the operating envelope in terms of temperature, altitude, Mach number, humidity and ice water content but also where the ice crystals generation system can operate continuously.
2015-06-15
Technical Paper
2015-01-2112
Thomas Schlegl, Michael Moser, Hubert Zangl
We present a system of completely autarkic temperature and capacitive icing sensors for aircraft. The consequences of icing on aircraft are described, for example, in [1] and [2]. Flexible (i.e. bendable) sensors, which are truly wireless and do not require maintenance, are easily mounted to almost any point on the aircraft surface (e.g. wings, fuselage, rudder, elevator, etc.). The entire sensing unit has a size of less than 100 mm times 170 mm (3.397 in times 6.693 in). The overall thickness can be kept lower than 2 mm (0.079 in) at the current status of development. It comprises the sensor front-end, processing electronics, buffered solar harvesting and a low-power radio frequency transmitter. The system transmits measurement results via an RF link to a monitoring system, which comprises a receiver antenna and a receiver circuit located at a suitable position on the aircraft. The employed sensor principle was first suggested in [3].
2015-06-15
Technical Paper
2015-01-2150
Katsuaki Morita, Hirotaka Sakaue, Taro Tanaka, Takeshi Yoshida, Nadine Rehfeld, Andreas Brinkmann, Katrin Lummer, Gerhard Pauly
Anti-icing or deicing of an aircraft is necessary for a safe flight operation. We have started the JEDI-ACE project (Japan-European De-Icing Aircraft Collaborative Exploration) as collaboration between EU nations and Japan since November 2012. This project aims to provide an innovative concept of an integrated ice protection system. An overview of this project will be presented in a separate paper by JEDI-ACE team. In this project, Japan Aerospace Exploration Agency (JAXA) develops icephobic coatings as an anti-icing purpose. Coating developments by Fuji Heavy Industries Ltd and Fraunhofer IFAM will be presented in separate papers by those institutions. In this paper, we will include our progress summary of the coating development and evaluation by JAXA. We will include our chemical components of the developed coatings as well as the evaluation of those coating. The developed coating is based on poly-tetra fluoroethylene (PTFE) particle bonded by a polymer.
2015-06-15
Technical Paper
2015-01-2148
Erdem Ayan, Serkan Ozgen, Canibek Murat, Erhan Tarhan
Ice crystal ingestion to aircraft engines may cause ice to accrete on internal components, leading to flameout, mechanical damage, rollback, etc. Many incidents occur due to the engine failures especially at high altitude convective weather conditions. Thus, in the framework of HAIC FP7 European project, the physical mechanisms of ice accretion on surfaces exposed to ice-crystal and mixed-phase conditions are investigated. Within the HAIC FP7 European project, TAI will implement models related to the ice crystal accretion calculation to the existing ice accumulation prediction program for droplets, namely TAICE. Considered models include heat transfer & phase change model, drag model and impact model. Moreover, trajectory model and Extended Messinger Model require some modifications to be used for ice crystal accretion predictions.
2015-06-15
Technical Paper
2015-01-2092
David M. Orchard, Catherine Clark, Myron Oleskiw
As a result of a series of international collaborative projects to measure and assess aircraft icing environments that contain Supercooled Large Droplets (SLDs), it has been demonstrated that the current icing envelopes, e.g., Code of Federal Regulations (CFR) 14 Part 25 Appendix C, do not adequately capture conditions where SLDs are present. Consequently, regulatory authorities are considering extensions to the certification requirements to include SLD environments. In order to demonstrate compliance to an updated icing certification that includes SLD conditions, airframe and aircraft component manufactures will have an increased need for access to test facilities that can simulate this environment. To address this need, a series of tests have been conducted within the NRC’s Altitude Icing Wind Tunnel (AIWT) to examine the feasibility of expanding its current capabilities to include the SLD icing envelope.
2015-06-15
Technical Paper
2015-01-2120
Yong Han Yeong, Eric Loth, Jack Sokhey, Alexis Lambourne
Superhydrophobic coatings have shown promise in reducing ice adhesion on a surface. However, recent superhydrophobic ice adhesion studies were conducted at either ice accretion conditions that do not resemble aerospace icing conditions, or at low super-cooled droplet impact speeds (less than 10 m/s). Therefore, a detailed experiment was conducted to measure the ice adhesion strength of various superhydrophobic coatings in an icing wind tunnel at an air speed of 50 m/s and at a temperature of -15°C with a super-cooled icing cloud consisting of 20 µm droplets. The ice was accreted on 3 mm thick, 30 mm diameter discs and then removed by pressurized nitrogen through the access hole in a tensile direction for a measurement of the ice fracture energy. Results showed no relationship between coating wettability parameters (water contact and receding angles) with ice fracture energy but depicted a general increase in fracture energy with increasing surface auto-correlation lengths.
2015-06-15
Technical Paper
2015-01-2157
Mengyao Leng, Shinan Chang, Yuanyuan Zhao
Aircraft icing causes a great threaten to flight safety. With the development of anti/de-icing systems for aeronautics, some attention is paid on coating strategies for reducing the total amount of water present on the surface. By application of hydrophobic or super-hydrophobic coatings, characterized by low surface wettability, shedding of liquid from the surface can be enhanced. The motivation behind this work is to identify the way that wettability affects the motion of runback water, and establish an empirical formula of critical departure diameter. In order to contain the effect of surface wettability, it is necessary to obtain an accurate model for calculating dynamic contact angle (DCA). Instead of average static contact angle or empirical equation, the formula used in this work is derived theoretically, as a function of the capillary number, advancing and receding contact angle, and the roughness of the solid surface.
2015-06-15
Technical Paper
2015-01-2149
Caroline Laforte, Caroline Blackburn, Jean Perron
Ideally, an icephobic coating applied to ice-exposed surfaces appears to be an interesting solution to prevent ice build-up. Over the last decade, developments of efficient icephobic coatings were multiplied. Some materials that reduce ice adhesion have been developed from which the ice can be more easily shed, possibly even with existing forces such as wind, gravity and vibrations. This paper will depict icephobic coating performances of 262 different coatings and 11 grease type substrates tested over the past 10 years at the Anti-Icing Materials International Laboratory (AMIL). Since 2003, the icephobic performance is evaluated with two main test methods. A first test method was developed in regards to measuring the ice adhesion and its reduction. A second test was then developed to measure the ice accumulation reduction.
2015-06-15
Technical Paper
2015-01-2135
Martin Schulz, Michael Sinapius
A designer of a new mechanical ice protection system for airplanes needs to know how much and in which way he has to deform the surface to break off the ice. The ice adhesion strength is often used as design value. To measure the adhesive strength several methods have been published. This paper presents a review about those methods and discusses the way the adhesion strength is derived. Finite Element Method is used to give a good insight into the stress state at failure for different load cases. The implication of these illustrations is that equations which use only ultimate force and total interfacial area to calculate adhesion strength miss the local stress state at the crack tip and the complex process of crack growing. Hence the derived adhesion strength may not be comparable with others, because they depend in fact on neglected parameters like specimen size, substrate thickness and stiffness.
2015-06-15
Technical Paper
2015-01-2159
Philipp Grimmer, Jakob Barz, Michael Haupt, Christian Oehr, Thomas Hirth
The formation of ice on surfaces of technical devices or transportation vehicles can lead to several problems, like reduced functionality, reduced energy efficiency or operational safety. As known de-icing methods use a high amount of energy or environmentally harmful chemicals, research has focused lately on passive de-icing by functional surfaces with an improved removal of ice (de-icing) or a reduced formation of it (anti-icing). Inspired by the Lotus plant leaf from nature, a “super-hydrophobic” surface can be produced by the combination of micro-structures and a hydrophobic surface coating. By a hot stamping process we have generated differently shaped microstructures (cylinders, ellipses and lines) on polyurethane films which are afterwards coated by a PECVD process with thin, hydrophobic fluorocarbon or silicone-like films. PU films are suitable for outdoor use, because they are resistant against erosion and UV radiation.
2015-06-15
Technical Paper
2015-01-2160
Alidad Amirfazli
Coatings that shed drops can help with icing mitigation. Shedding of a drop depends on surface wettability. To characterize the shedding of a drop, in an aerodynamic context, the minimum air velocity to displace the drop is measured, i.e., the critical air velocity. Recently, superhydrophobic surfaces (SHS) with their ability to shed drops have gained much attention to combat icing. However, questions remain about their performance when exposed to UV, or water for long periods. In this study of its first kind, the effect prolonged UV and water exposure on shedding of drops from 6 different SHS (four commercially available coatings (C1 to C4), and two developed in-house, S1 and S2) was investigated in an icing wind tunnel. Critical air velocity, and contact angle values show that UV-treatment has a stronger adverse effect for S1 and C1 surfaces, compared to other coatings. Water treatment adversely affects S1, C1 and C2 samples more than other samples.
2015-06-15
Technical Paper
2015-01-2137
Daniel R. Adriaansen, Paul Prestopnik, George McCabe, Marcia Politovich
Advancements in numerical weather prediction (NWP) modeling continue to enhance the quality of in-flight icing forecasts and diagnoses. When performing a diagnosis of current in-flight icing conditions, observational datasets can be combined with NWP model output to form a more accurate representation. These diagnoses are traditionally tied to a three-dimensional grid, typically the grid of the NWP model data chosen for use. Surface observations are heavily relied upon when performing in-flight icing diagnoses to identify cloud coverage and cloud base height above observing stations. One of the major challenges of using these point-based or otherwise limited observations of cloud properties is extending the influence of the observation to nearby points on the grid. For example, we seek an improved solution to the problem of combining point-based METARs observations with NWP model grids over the current method.
2015-06-15
Technical Paper
2015-01-2076
Caroline Laforte, Neal Wesley, Marc Mario Tremblay
In North America, about ten million kilograms of runway deicers are applied on airport runways to ensure safe takeoffs and landings of aircraft in adverse conditions. Although some of the chemicals are recovered, much of them are dispersed through aviation operations to airport’s surrounding environment. Little focus has been given into assessing and determining optimal quantities of deicers to be used on runways, that at the same time retain a high degree of safety, while reducing risks to the environment and improving airport efficiencies. Improved deicer performance tests would allow for the development of more environmentally sustainable deicers, through their improved performance. A better assessment of their deicing and anti-icing performance along with their degree of skid resistance on runway pavement, will help in the development of the next generation of runway de/anti-icing chemicals to ensure improved sustainable and safe aircraft takeoffs and landings.
2015-06-15
Technical Paper
2015-01-2108
Julien Cliquet, Christian Bartels, Carlos Bautista
SAE Aircraft , Engines, Structures Icing Conference, 22-25 June 2015, Prague A combined post-processing method for SLD modeling J. Cliquet, C. Bartels, C. Bautista-Infante, Airbus Operations Abstract Supercooled Large Droplets (SLD) have taken an increasingly important place in the airframe icing over the past 15 years. Awareness of the aircraft SLD icing hazard has focused particular attention following several aircraft accidents, especially that of the ATR-72 on 31 October 1994 (Ref. [1]). The actual certification envelope defined by 14 CFR Part 25 Appendix C: Atmospheric Icing Conditions for Aircraft Certification, accounts for an icing envelope characterized by water droplet diameters up to 50 μm. International airworthiness authorities have jointly developed an extension of Appendix "C", named "Appendix O", to account for SLD conditions in the aircraft certification process.
2015-06-15
Technical Paper
2015-01-2158
Tatsuma Hyugaji, Shigeo Kimura, Haruka Endo, Mitsugu Hasegawa, Hirotaka Sakaue, Katsuaki Morita, Yoichi Yamagishi, Nadine Rehfeld, Benoit Berton, Francesc Diaz, Tarou Tanaka
Recently coatings have been considered as promising preventive measures for in-cloud icing which may occur at the leading edge area of the lifting surface of aircraft in cold climate. In terms of the wettability, coating reveals hydrophobicity or hydrophilicity depending on its property. At the same time it has high or low values on the ice adhesion strength. It is then required that users should find out which of anti-icing or de-icing coating can apply to in order to make full use of the distinguished characteristics. For all that, coating cannot prevent ice accretion by itself unfortunately, which means that no perfect icephobic coatings have been developed up to the present. Thus, coatings apply to the surfaces with devices such as an electric heating system or a load-applying machine such that they can function with less energy and more effectiveness.
2015-06-15
Technical Paper
2015-01-2130
Melissa Bravin, J. Walter Strapp, Jeanne Mason
In response to the occurrence of jet engine powerloss and damage events associated with deep convective clouds containing high concentrations of ice crystals, several research efforts are underway. Several flight measurement programs devoted to the collection of in-situ and remote sensing of clouds have been conducted over the past few years. The most recent in Darwin, Australia, from January-March 2014, and its follow-up planned for Cayenne, French Guiana, in May 2015, involve the use of a highly instrumented research aircraft with instrumentation specially designed to make accurate in-situ total water content (TWC) and median mass diameter (MMD) measurements of the high concentration areas of deep convection. The data will be used for atmospheric research related to understanding the microphysics of deep convection, and improving the ability to predict, detect and avoid these clouds.
2015-06-15
Technical Paper
2015-01-2078
Alric Rothmayer, Hui Hu
A strong air/water interaction theory is used to develop a fast simplified model for the trapping of water in a film that flows over sub-grid surface roughness. The sub-grid model is used to compute correction factors that can alter mass transport within the film. This sub-grid model is integrated into a covariant film mass transport model for film flow past three-dimensional surfaces of a form suitable for aircraft icing codes. Sample calculations are presented to illustrate the application of the model. Aircraft icing codes usually consist of an aerodynamic solver, a droplet trajectory solver and a mechanism to grow the ice surface. Recently, icing codes have also made use of simple models for surface water transport, typically through a film lubrication model.
2015-06-15
Technical Paper
2015-01-2102
Guilin Lei, Wei Dong, Jianjun Zhu, Mei Zheng
The numerical simulation of ice melting process on an iced helicopter rotor blade is presented. The ice melting model uses an enthalpy-porosity formulation, and treats the liquid-solid mushy zone as a porous zone with porosity equal to the liquid fraction. The ice shape on the blade section is obtained by the icing code with a dynamic mesh module. Both of the temperature change and the ice-melting process on the rotor blade section surface are analyzed. The phenomenon of ice melting is analyzed through the change of temperature and liquid fraction on the abrasion/ice interface. The liquid fraction change as with time on the abrasion/ice surface is observed, which describes the ice-melting process well. The numerical results show that the ice melting process can be simulated effectively by the melting model. The de-icing process can be monitored by observing the change of the liquid fraction of the area around the abrasion/ice interface.
2015-06-15
Technical Paper
2015-01-2093
Maxime Henno
A numerical tool has been developed for predicting the unsteady behavior of the thermal wing ice protection systems (WIPS). The code was developed to account for a multi-layer composite structure. The performance predictions of a WIPS integrated into a metallic or into a composite structure can thus be achieved. The tool enables the simulation of unsteady anti-icing operations, for example, the WIPS may be activated with delay after entering into the icing conditions. In this case, ice starts to accrete on the leading edge before the WIPS heats up the skin. Another example is the ground activation of the WIPS for several seconds to check its functionality: low external cooling may cause high thermal constraints that must be estimated with accuracy to avoid adverse effects on the structure. The simulations give further opportunities compared to the current practice.
2015-06-15
Technical Paper
2015-01-2153
David Serke, Michael King, Andrew Reehorst
In early 2015, the NASA Glenn Research Center will conduct a field campaign based out of Cleveland, Ohio with 60 flight hours on the Twin Otter icing research aircraft. The purpose of the field campaign is to test several prototype algorithms meant to detect the location and severity of in-flight icing within the terminal airspace. The terminal airspace is currently defined as within 25 kilometers horizontal distance of the terminal, which in this case was Hopkins International Airport in Cleveland. Two new and improved algorithms have been developed and will be operated during the field campaign. The first is the 'NASA Icing Remote Sensing System', or NIRSS. NASA and the National Center for Atmospheric Research have developed this icing remote sensing technology which has demonstrated skill at detecting and classifying icing hazards in a vertical column above an instrumented ground station1,2.
2015-06-15
Technical Paper
2015-01-2097
Timothy A. Shannon, Stephen T. McClain
As ice begins to accrete on an aircraft in flight, the stochastic nature of the droplet impingement process dictates that the accreted ice is uneven along the surface resulting in roughness. Because of the varying convection along the surface and local shear rates along the surface, the resulting roughness statistical characteristics on an unswept wing are not constant along the streamwise direction. However, historical studies of roughness on iced airfoils performed in the NASA Icing Research Tunnel (IRT) at NASA Glenn Research Center employed image analysis approaches to create parametric representations of ice roughness element development over time. Because of the parametric descriptions and the limitations of the surface characterizations, ice roughness is often treated in analytical approaches and computational models as having constant parametric properties over the entire ice accretion area.
2015-06-15
Technical Paper
2015-01-2086
Matthew Grzych, Terrance Tritz, Jeanne Mason, Melissa Bravin, Anna Sharpsten
The significant problem of engine power-loss and damage associated with ice crystal icing (ICI) was discussed in Mason et al [1]. These engine events included engine surge, stall, flameout, rollback and compressor damage and were connected to the ingestion of high concentrations of ice crystals associated with deep convective clouds. Since that time, several industry and government collaborations have taken steps to address the many technological requirements identified by the Engine Harmonization Working Group (EHWG) in 2007 [2]. The EHWG identified the need for in-situ measurements of ice concentration and size distribution to aid in the development of engine test facilities and methods to simulate the environment. Researchers are also addressing a second technology requirement identified by the EHWG: fundamental studies on the physics of ice accretion in the engine. Both efforts require study environments to be similar to the ones that cause in-service engine events.
2015-06-15
Technical Paper
2015-01-2087
Delphine Leroy, Emmanuel Fontaine, Alfons Schwarzenboeck, J. Walter Strapp, Lyle Lilie, Julien Delanoe, Alain Protat, Fabien Dezitter, Alice Grandin
Title: HAIC/HIWC field campaign - specific findings on PSD microphysics in high IWC regions from in situ measurements: crystal size distribution characteristics, ice density, and median mass diameters Authors: Delphine Leroy (CNRS-LaMP), Emmanuel Fontaine (CNRS-LaMP), Alfons Schwarzenboeck (CNRS-LaMP), J.
2015-06-15
Technical Paper
2015-01-2090
Serkan Ozgen, Volkan Tatar, Nermin Ugur, Ilhan Gorgulu
This study aims to assess the effects of icing conditions on benchmark and real engine nacelle geometries. The calculations are done in both liquid and glaciated phase clouds. The computational tool used for prediction consists of four main modules; flow field solution, trajectory calculations, thermodynamic model and ice growth calculation. The flow solver in the current computational tool is a panel solver where the strengths of the singularity elements are varied in order to meet the required mass flow rate through the nacelle/engine. A RANS solver is in the process of being integrated into the current solver. The trajectory calculations are done both for liquid phase clouds including SLD effects like breakup and splash, and for solid/mixed phase clouds. The latter will take ice crystal drag coefficient, phase change, non-uniform flow field temperature, impact phenomena like erosion, bounce, etc. into account. The ice growth model is the Extended Messinger Model.
2015-06-15
Technical Paper
2015-01-2082
Andreas Tramposch, Wolfgang Hassler, Reinhard F.A. Puffing
Certain operating modes of the Environmental Control System (ECS) of passenger aircraft are accompanied with significant frost formation in a number of pivotal parts of the system. These icing phenomena mostly occur during ground operation in hot regions with high humidity and are caused by the presence of remnant water in the preconditioned airstream. This water may appear – depending on the operating conditions – in the form of liquid water droplets, frozen particles and also water vapor. Icing conditions particularly prevail downstream of the AC packs and, as a consequence, ice formation takes place in the Pack Discharge Duct (PDD) and the mixing manifold. The ice thereby accumulates at the walls of the PDD and the mixing manifold and leads to a change of the flow geometry, which particularly increases the pressure drop in the system. This reduces the efficiency of the AC system and may even lead to a shutdown (of parts) of the system.
2015-05-20
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2015-04-14
Technical Paper
2015-01-0494
Sulki Seong, Wangoo Kim, Daesung Bae, Seungpyo Lee, Younggeol Cho, Kyeongdeok Yang
Bearing is an important part for supporting the weight and transmits power. Rotating bearing is required excellent durability. Various studies have been conducted long time, for predict performance and durability of the bearing. However, prediction of the bearing durability has been used expression computation method using a theoretical formula between the raceway and ball. Flange analysis is commonly used structural analysis. Such an approach, have assumed to be static load. So it is difficult to consider the dynamic characteristics (Centrifugal force, Gyroscope effect) of the bearing. In order to predict the accurate bearing endurance life, it should be considering the dynamic characteristics. This paper proposes the method for bearing endurance life prediction considering dynamic characteristic. Between the raceway and ball contact is one of the important factors to take into account the dynamic characteristics of the bearing.
2015-04-14
Technical Paper
2015-01-0204
Biswajit Panja, Lars Wolleschensky
Abstract In this paper we propose a secure wireless sensor network system for vehicle health monitoring (VHM). We discuss the architecture of the proposed model, and it's implementation in vehicles. Modified AES-CCM is used to provide confidentiality in the network. In the proposed scheme combination of interactive and non-interactive methods are used for reliable message delivery.
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