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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
2015-01-2076
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
2015-01-2078
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
2015-01-2093
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
2015-01-2097
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
2015-01-2157
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
2015-01-2102
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
2015-01-2120
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
2015-01-2160
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
2015-01-2135
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
2015-01-2096
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
2015-01-2158
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
2015-01-2159
Philipp Grimmer, Swarupini Ganesan, Michael Haupt, Jakob Barz, 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
2015-01-2092
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.
2015-05-20
Book
This is the electronic format of the Journal.
2015-04-16
Book
Robert J. Flemming
The effects of inflight atmospheric icing can be devastating to aircraft. Universities and industry have been hard at work to respond to the challenge of maintaining flight safety in all weather conditions. Proposed changes in the regulations for operation in icing conditions are sure to keep this type of research and development at its highest level. This is especially true for the effects of ice crystals in the atmosphere, and for the threat associated with supercooled large drop (SLD) icing. This collection of ten SAE International technical papers brings together vital contributions to the subject. Icing on aircraft surfaces would not be a problem if a material were discovered that prevented the freezing and accretion of supercooled drops. Many options that appeared to have promising icephobic properties have had serious shortfalls in durability.
2015-04-15
WIP Standard
ARP4990B
This SAE Aerospace Recommended Practice (ARP) provides to the aerospace industry a procedure for the consistent and accurate calculation of fuel flow using turbine flowmeters during development, production, and post overhaul/repair gas turbine engine testing.
2015-04-15
Book
“Spotlight on Design” features video interviews and case study segments, focusing on the latest technology breakthroughs. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. In the episode “Diagnostics and Prognostics: Proactive Maintenance and Failure Prevention” (21:04), Delphi engineers explain how they leverage the growing number of sensors and computing power in vehicles to diagnose and proactively solve emerging mechanical or electronic problems, before a breakdown occurs. This video also looks at the next generation of automotive telematics, with HEM Data demonstrating how in-vehicle data acquisition is used to monitor the inner workings of vehicles.
2015-04-15
Book
“Spotlight on Design: Insight” features an in-depth look at the latest technology breakthroughs impacting mobility. Viewers are virtually taken to labs and research centers to learn how design engineers are enhancing product performance/reliability, reducing cost, improving quality, safety or environmental impact, and achieving regulatory compliance. Telematics, the convergence of telecommunications and informatics, uses electronic and computer technology built in to the vehicle to provide vehicle tracking, satellite navigation, wireless technology, and diagnostic information. In the episode “Diagnostics and Prognostics: Telematics Deep Dive” (8:09), an engineer from Delphi’s Telematics program discusses the advantages and challenges of telematics devices for the automotive industry, demonstrates the installation of an aftermarket telematics device, and shows how telematics can enhance diagnostics and preventative maintenance.
2015-04-14
Collection
Model Validation and Verification invite papers that deal with the theoretical and/or applied aspects of one or more of the following representative topics: model development, model correlation/calibration, model verification, model validation, uncertainty quantification, uncertainty propagation, validation metrics, predictive capability assessment, etc.
2015-04-14
Collection
This collection of technical papers will address theoretical developments and automotive applications in RBDO and Robust Design. Topics include: computational algorithms for efficient estimation of reliability, Monte Carlo simulation, Bayesian reliability, Dempster-Shafer Evidence Theory, and Multi-Disciplinary Optimization, among others.
2015-04-14
WIP Standard
J2892
This document establishes standard graphical symbols and color conventions for use in either still (static) or animated graphics used for communicating service information. This document’s purpose is to communicate conventions for using those symbols and colors to accurately and consistently communicate intended information via graphics-based documentation. These practices are intended for use in service procedures, assembly instructions, training materials, and similar applications when trying to minimize the amount of human natural language text used within the document. The still and animated graphical conventions referenced should support effective communication via paper and “traditional” electronic media. The conventions can also extend to documenting via additional electronic delivery paradigms such as Augmented Reality (AR).
2015-04-14
Technical Paper
2015-01-0881
Sunyu Tong, Haimiao Li, Zhaohui Yang, Jun Deng, Zongjie Hu, Liguang Li
Abstract An ion current sensor is employed in a 4 cylinder production SI engine for combustion diagnosis during combustion process, knock, and low speed pre-ignition (LSPI) detection. The results show that the ion current peak value and ion current peak phase have strong correlation with the cylinder pressure and pressure peak phase respectively. The COV of ion current integral value is greater than the COV of IMEP at the same operating condition. Results show that the ion current signal is sensitive to different lambdas. Using ion current signal, the knock in any given cylinder can be detected. Importantly, the ion sensor successfully detected the low speed pre-ignition (LSPI) about more than 20 °CA before spark ignition.
2015-04-14
Technical Paper
2015-01-0926
Tianyun Li, Min Xu, David Hung, Shengqi Wu, Siqi Cheng
Abstract Comparing with port-fuel-injection (PFI) engine, the fuel sprays in spark-ignition direct-injection (SIDI) engines play more important roles since they significantly influence the combustion stability, engine efficiency as well as emission formations. In order to design higher efficiency and cleaner engines, further research is needed to understand and optimize the fuel spray atomization and vaporization. This paper investigates the atomization and evaporation of n-pentane, gasoline and surrogate fuels sprays under realistic SIDI engine conditions. An optical diagnostic technique combining high-speed Mie scattering and Schlieren imaging has been applied to study the characteristics of liquid and vapor phases inside a constant volume chamber under various operating conditions. The effects of ambient temperature, fuel temperature, and fuel type on spray atomization and vaporization are analyzed by quantitative comparisons of spray characteristics.
2015-04-14
Journal Article
2015-01-0918
Daniel Duke, Andrew Swantek, Alan Kastengren, Kamel Fezzaa, Christopher Powell
Abstract Cavitation plays an important role in fuel injection systems. It alters the nozzle's internal flow structure and discharge coefficient, and also contributes to injector wear. Quantitatively measuring and mapping the cavitation vapor distribution in a fuel injector is difficult, as cavitation occurs on very short time and length scales. Optical measurements of transparent model nozzles can indicate the morphology of large-scale cavitation, but are generally limited by the substantial amount of scattering that occurs between vapor and liquid phases. These limitations can be overcome with x-ray diagnostics, as x-rays refract, scatter and absorb much more weakly from phase interfaces. Here, we present an overview of some recent developments in quantitative x-ray diagnostics for cavitating flows. Measurements were conducted at the Advanced Photon Source at Argonne National Laboratory, using a submerged plastic test nozzle.
2015-04-14
Technical Paper
2015-01-1405
Guanjun Zhang, Feng Yu, Zhigao OuYang, Huiqin Chen, Zhonghao Bai, Libo Cao
Abstract The combination of passive and active vehicle safety technologies can effectively improve vehicle safety. Most of them predict vehicle crashes using radar or video, but they can't be applied extensively currently due to the high cost. Another collision forecasting method is more economic which is based on the driver behavior and vehicle status, such as the acceleration, angular velocity of the brake pedal and so on. However, the acceleration and angular velocity of the brake pedal will change with the driver and the vehicle type. In order to study the effect of different drivers and vehicle types on the braking acceleration and angular velocity of the brake pedal, six volunteers were asked to drive five vehicles for simulating the working conditions of emergency braking, normal braking, inching braking and passing barricades under different velocities. All the tests were conducted on asphalt road, and comprehensive experimental design was used to arrange tests.
2015-04-14
Technical Paper
2015-01-0267
Ryoichi Inada, Teppei Hirotsu, Yasushi Morita, Takahiro Hata
Abstract The ISO 26262 is a functional safety standard for road vehicles. The standard requires manufacturers to conduct quantitative assessment of the diagnostic coverage (DC) of products. The DC is defined as the percentage of failure probability covered by safety mechanisms. However, DC evaluation methods for drift faults, in which the change in element values is not constant, have not been discussed. In this paper, we propose a DC evaluation method for analog circuits with drift faults. With this method, we first parameterize the effect of drift faults onto a bounded region then split the region into safe fault, hazardous detectable fault, and hazardous undetectable fault regions. We evaluate the classification rate distribution by the area ratios of these regions.
2015-04-14
Journal Article
2015-01-0441
Takashi Takiguchi, Yusuke Yano, Yasuhiro Takii, Nobuyuki Ohta
Abstract With demands for enhanced environmental performance such as fuel economy, the tendency has been to reduce the amount of wind introduced to the engine room to reduce drag. Meanwhile, exhaust gas temperatures are increasing in order to reduce emissions concentrations. As a result, the temperature environments for parts inside the engine room and underfloor parts are becoming harsher, and accurately understanding the temperature environments of parts is crucial in determining Engine room component layout during vehicle development and applying effective thermal countermeasures. Computational fluid dynamics (CFD) are effective for understanding complex phenomena such as heat generation and cooling. However, this paper reports the development of a method for accurately calculating the vehicle temperature distribution through identification from test results.
2015-04-14
Technical Paper
2015-01-0439
Daniel B. Kosinski
Abstract The current reliability growth planning model used by the US Army, the Planning Model for Projection Methodology (PM2), is insufficient for the needs of the Army. This paper will detail the limitations of PM2 that cause Army programs to develop reliability growth plans that incorporate unrealistic assumptions and often demand that infeasible levels of reliability be achieved. In addition to this, another reliability growth planning model being developed to address some of these limitations, the Bayesian Continuous Planning Model (BCPM), will be discussed along with its own limitations. This paper will also cover a third reliability growth planning model that is being developed which incorporates the advantageous features of PM2 and BCPM but replaces the unrealistic assumptions with more realistic and customizable ones.
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