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Viewing 241 to 270 of 4795
2011-10-18
Journal Article
2011-01-2643
Luis Rabelo, Jorge Bardina, Yanshen Zhu, Jeppie Compton
This paper discusses the ground and range operations for a Shuttle derived Heavy-Lift Vehicle being launched from the Kennedy Space Center on the Eastern range. Comparisons will be made between the Shuttle and a heavy lift configuration (SLS-ETF MPCV - April 2011) by contrasting their subsystems. The analysis will also describe a simulation configuration with the potential to be utilized for heavy lift vehicle processing/range simulation modeling and the development of decision-making systems utilized by the range. In addition, a simple simulation model is used to provide the required critical thinking foundations for this preliminary analysis.
2011-10-18
Journal Article
2011-01-2665
Michael Roemer
One of the inherent functions of an integrated vehicle health management (IVHM) system is the reasoning capability that is built on the knowledge of how the individual line replaceable units (LRU) and subsystems are functionally interconnected across the vehicle. Once known and mathematically represented, the IVHM system has the ability to utilize knowledge obtained from the individual LRU/subsystems to determine the overall health state and functional capabilities of the vehicle. This process must go beyond the basic diagnoses of the observed health condition of the isolated subsystems and their remaining functionality. The IVHM reasoning process described herein employs a hierarchical structure that accounts for the failure modes at the LRU level and can also determine the functional impact of those LRUs in terms of remaining functional/operational availability at the subsystem and vehicle levels.
2011-10-18
Technical Paper
2011-01-2704
Ravi Rajamani, Nicholas Waters
The use of Engine Health Management (EHM) systems has been growing steadily in both the civilian and the military aerospace sectors. Barring a few notable exceptions (such as certain temperature and thrust margin monitoring) regulatory authorities around the world have not required these systems to be certified in any way. This is changing rapidly. New airframes and engines are increasingly being designed with the assumption that EHM will be an integral part of the way customers will operate these assets. This leads to a need for better guidelines on how such systems should be certified. The SAE E-32 committee on Propulsion System Health Monitoring is leading an industry-wide effort to develop a set of guidelines for certifying EHM systems.
2011-10-18
Journal Article
2011-01-2702
Christian Modest, Kai Schories, Hauke Peer Lüdders, Frank Thielecke
In the paper at hand a model-based development approach for a diagnostic system for a multifunctional fuel cell system architecture will be presented. The approach consists primarily of four parts. The first part is a description of general steps needed to build an accurate component-based model of the system using a state of the art model-based diagnostic reasoning tool. As a first result there will be a static simulation model for nominal system behavior. The second part of the approach deals with the identification of safety critical failure conditions (SCFC) at a system level, e.g. low Power. The SCFCs are then mapped into the model. This means that categorized physical quantities and monitoring executives are chosen, that are appropriate for representing the specific SCFCs, e.g. low voltage at outlet of DC-DC converter module. According to step two there will be conflicts, meaning discrepancies between the simulated nominal and the mapped behavior.
2011-10-18
Journal Article
2011-01-2714
Vincent Rouet, Bruno Foucher
TRIADE is a European Union project that focuses on the development of technological building blocks for Structure Health Monitoring (SHM) sensing devices in aeronautics. It is funded under the 7th framework program. In terms of objectives, the TRIADE project focuses on providing these technological building blocks and fully integrated prototypes in order to achieve power generation, power conservation, energy management and embedded powerful intelligence for data processing and storage for SHM sensing devices. The principal technological building blocks that the TRIADE project will provide are: - A low profile battery with high energy density which will be able to function in a harsh environment, - An energy harvester from vibration and electromagnetic RF, - Ultra low power sensors which will be designed in SOI technology, and - A neural network for data recording and damage assessment.
2011-10-18
Journal Article
2011-01-2700
Ahmed Onsy, Brian A. Shaw, Jishan Zhang
Micro-pitting is a fatigue effect that occurs in geared transmission systems due to high contact stress, and monitoring its progression is vital to prevent the eventual failure of the tooth flank. Parameter signature analysis has been successfully used to monitor bending fatigue failure and advanced phases of gear surface fatigue failure such as macro-pitting and scuffing. However, due to modern improvements in steel production the main cause of gear contact fatigue failure can be attributed to surface micro-pitting rather than sub-surface phenomena. Responding to the consequent demand to detect and monitor the progression of micro-pitting, this study experimentally evaluated the development of micro-pitting in spur gears using vibration and oil debris analysis. The paper presents the development of an online health monitoring system for use with back-to-back gear test rigs.
2011-10-18
Journal Article
2011-01-2800
Florian Moliere, Alain Bravaix, Bruno Louis Foucher, Philippe Perdu
Up to now, the reliability achieved by COTS components was largely sufficient for avionics, in terms of failure rate as well as time to failure. With the implementation of new and more integrated technologies (90 nm node, 65 nm and below), the question has arisen of the impact of the new technologies on reliability. It has been stated that the lifetime of these new technologies might decrease. The drift is expected to be technology dependent: integration, technology node, materials, elementary structure choices and process pay a key role. Figures have been published, which gives smaller lifetime than the 30 years generally required for avionics. This would of course impact not only the reliability, but also the maintenance of COTS-based avionics. Hence a new policy should be defined for the whole COTS supply chain. Faced with these impending risks, different methodologies have been developed [1], [2].
2011-10-04
Technical Paper
2011-36-0279
Carlos Eduardo Viana Ribeiro, Marcelo Lopes de Oliveira e Souza
Life-critical aeronautical projects are increasing their lifecycle up to the point where a product is developed to be available in the market for more than 70 years, but requiring daily service support and replacement parts. Therefore, unavailability of components or services can have a severe impact over the product through its lifecycle. In this work we study some causes of unavailability of components and services and their effects over the lifecycle of an aeronautical project, to propose recommendations, alternatives and actions to be taken in the early phases of project development to help mitigate such effects over the product lifecycle. To do that, we initially present the causes of unavailability of components and services. Then, we discuss some of their effects over the lifecycle of an aeronautical project.
2011-09-13
Technical Paper
2011-01-2247
Mohammad Rezvani, Mohamed AbuAli PhD, Seungchul Lee, Jay Lee, Jun Ni PhD
Batteries are widely used as storage devices and they have recently gained popularity due to their increasing smaller sizes, lighter weights and greater energy densities. These characteristics also render them suitable for powering electric vehicles. However, a key gap exists in that batteries are solely used as storage devices with a lack of information flow. Next-generation battery technologies will constitute the enabling tools that would lead to information-rich batteries, thus allowing the transparent assessment of a battery's health as well as the prediction of a battery's remaining-useful-life (RUL) and its subsequent impact on vehicle mobility. Various methods and techniques have been employed to predict battery RUL in order to improve the accuracy of the State of Charge (SoC) estimation.
2011-09-11
Technical Paper
2011-24-0159
Tobias Spilker, Antonius Voncken PhD
Piston rings are faced with a broad range of demands like optimal sealing properties, wear properties and reliability. Even more challenging boundary conditions must be met when latest developments in the fields of direct injection as well as the application of bio fuels. This complex variety of piston ring design requirements leads to the need of a comprehensive simulation model in order to support the development in the early design phase prior to testing. The simulation model must be able to provide classical objectives like friction analysis, wear rate and blow-by. Furthermore, it must include an adequate oil consumption model. The objective of this work is to provide such a simulation model that is embedded in the commercial MBS software ‘FEV Virtual Engine’. The MBS model consists of a cranktrain assembly with a rigid piston that contains flexible piston rings.
2011-09-11
Journal Article
2011-24-0151
Federico Millo, Marco Badami, Andrea Bianco, Enrico Delogu
The fuel injection plays a crucial role in determining the mixture formation process in Gasoline Direct Injection (GDI) engines. Pollutant emissions, and soot emissions in particular, as well as phenomena affecting engine reliability, such as oil dilution and injector coking, are deeply influenced by the injection system features, such as injector geometric characteristics (such as injector type, injector position and targeting within the combustion chamber) and operating characteristics (such as injection pressure, injection phasing, etc.). In this paper, a new CFD methodology is presented, allowing a preliminary assessment of the mixture formation quality in terms of expected soot emissions, oil dilution and injector coking risks for different injection systems (such as for instance multihole or swirl injectors) and different injection strategies, from the early stages of a new engine design.
2011-09-11
Technical Paper
2011-24-0145
Fabrizio Ponti, Matteo De Cesare, Vittorio Ravaglioli
Modern internal combustion engine control systems require on-board evaluation of a large number of quantities, in order to perform an efficient combustion control. The importance of optimal combustion control is mainly related to the requests for pollutant emissions reduction, but it is also crucial for noise, vibrations and harshness reduction. Engine system aging can cause significant differences between each cylinder combustion process and, consequently, an increase in vibrations and pollutant emissions. Another aspect worth mentioning is that newly developed low temperature combustion strategies (such as HCCI combustion) deliver the advantage of low engine-out NOx emissions, however, they show a high cylinder-to-cylinder variation. For these reasons, non uniformity in torque produced by the cylinders in an internal combustion engine is a very important parameter to be evaluated on board.
2011-09-11
Technical Paper
2011-24-0146
Ivan Arsie, Ivan Criscuolo, Cesare Pianese, Matteo De Cesare
The paper deals with the steady-state optimal tuning of control variables for an automotive turbocharged Diesel engine. The optimization analysis is based on an engine simulation model, composed of a control oriented model of turbocharger integrated with a predictive multi-zone combustion model, which allows accounting for the impact of control variables on engine performance, NOx and soot emissions and turbine outlet temperature. This latter strongly affects conversion efficiency of after treatment devices therefore its estimation is of great interest for both control and simulation of tailpipe emissions. The proposed modeling structure is aimed to support the engine control design for common-rail turbocharged Diesel engines with multiple injections, where the large number of control parameters requires a large experimental tuning effort.
2011-09-11
Technical Paper
2011-24-0149
Andrea Catania, Roberto Finesso, Ezio Spessa
A new procedure for the real-time estimation of the EGR rate and charge oxygen concentration has been developed, assessed and applied to a low-compression ratio GMPT-E EURO V diesel engine. High EGR rates are usually employed in modern diesel engines to reduce combustion temperatures and NOx emissions, especially at medium-low load and speed conditions. The EGR rate is usually calibrated in steady-state conditions, but, under transient conditions, it can be responsible for misfire occurrence or non optimal combustion cycles, if not properly controlled. In other words, combustion instabilities can occur, especially during tip-in maneuvers, which imply transition from high EGR (low load) to low EGR (high load) rates. Misfire is determined by a temporary reduction in the intake charge oxygen concentration during the closure of the EGR valve.
2011-09-11
Technical Paper
2011-24-0067
Christian Donn, Wolfgang Zulehner, Daniel Ghebru, Ulrich Spicher, Matthias Honzen
Advanced thermal management systems in passenger cars present a possibility to increase efficiency of current and future vehicles. However, a vehicle integrated thermal management of the combustion engine is essential to optimize the overall thermal system. This paper shows results of an experimental heat flux analysis of a state-of-the-art automotive diesel engine with common rail injection, map-controlled thermostat and split cooling system. Measurements on a climatic chamber engine test bench were performed to investigate heat fluxes and energy balance in steady-state operation and during engine warm-up from different engine start temperatures. The analysis includes the influence of the operating point and operating parameters like EGR rate, injection strategy and coolant temperature on the engine energy balance.
2011-08-30
Technical Paper
2011-01-1965
Reijo Makinen, Nils-Olof Nylund, Kimmo Erkkilä lng, Pirjo Saikkonen, Arno Amberla
Helsinki Region Transport, Neste Oil, Proventia Emission Control and VTT Technical Research Centre of Finland carried out a 3.5 year PPP venture “OPTIBIO” to demonstrate the use of paraffinic renewable diesel (hydrotreated vegetable oil HVO) in city buses. The fleet test in Metropolitan Helsinki involving some 300 buses is the largest one in the world to demonstrate this new fuel. The fuels were a 30 % blend of renewable diesel and 100 % renewable diesel. This paper describes the overall set-up of the project, gives an overview of the emission results as well as presents experience from the field.
2011-08-30
Technical Paper
2011-01-1981
Sanghoon Kook, Minh Khoi Le, Srinivas Padala, Evatt R. Hawkes
Schlieren and shadowgraph imaging have been used for many years to identify refractive index gradients in various applications. For evaporating fuel sprays, these techniques can differentiate the boundary between spray regions and background ambient gases. Valuable information such as the penetration rate, spreading angle, spray structure, and spray pattern can be obtained using schlieren diagnostics. In this study, we present details of a z-type schlieren system setup and its application to port-fuel-injection gasoline sprays. The schlieren high-speed movies were used to obtain time histories of the spray penetration and spreading angle. Later, these global parameters were compared to specifications provided by the injector manufacturer. Also, diagnostic parameters such as the proportion of light cut-off at the focal point and the orientation of knife-edge (schlieren-stop) used to achieve the cut-off were examined.
2011-06-13
Technical Paper
2011-38-0010
Katsuaki Morita, Koji Okamoto, Akihito Aoki, Shigeo Kimura, Hirotaka Sakaue
Anti- or de-icing of an aircraft is necessary for a safe flight operation. Mechanical processes, such as heating and deicer boot, are widely used. Deicing fluids, such as ethylene glycol, are used to coat the aircraft. However, these should be coated every time before the take-off, since the fluids come off from the aircraft while cruising. We study a hydrophobic coating as an anti-icer for an aircraft. It is designed to coat on the aircraft without removal. Since a hydrophobic coating prevents water by reducing the surface energy, it would be an alternative to prevent ice on the aircraft. We provide a temperature-controlled room, which can control its temperature under icing conditions (-10 to 0 °C). The contact angle and the sliding angle are tested for various hydrophobic coatings. Candidate coatings are tested under super-cooled water spraying and under the representative in-flight icing conditions.
2011-06-13
Technical Paper
2011-38-0058
Arlene Beisswenger, Caroline Laforte, Jean Perron
Deicing fluids are used to remove and prevent ice formation on aircraft before takeoff. These fluids are essentially composed of water, a freeze point depressant (FPD) usually glycol, a surfactant or wetting agent and a corrosion inhibitor. All commercial fluids are qualified to SAE (Society of Automotive Engineers) specifications, which test for aerodynamic acceptance, anti-icing endurance, corrosion inhibition, material compatibility, fluid stability and environment. However, these tests have been built around a fluid with a glycol FPD. More recently, with environmental pressure, fluids with other FPDs have been developed and qualified. The other FPDs include: acetates and formate salts, sorbitol, and other undisclosed FPDs. The acetates and formates, which came out in the early 1990s led to suspected corrosion problems. This led to the additional requirement for corrosion tests for non-glycol deicing fluids in paragraph 3.1.1 of AMS1424.
2011-06-13
Technical Paper
2011-38-0045
Guy Fortin, Ilham Enneji, Arlene Beisswenger, Jean Perron
Deicing and anti-icing fluids are used to remove and prevent ice formation on aircraft before takeoff. Holdover times (HOT) published by the FAA are used by pilots as guidelines indicating the amount of effective time of a fluid under certain freezing precipitation types. However, the times on these tables are based on endurance time tests involving a visual estimate of failure on a flat plate [1]: when 30% of the fluid is covered with white snow under snow precipitation, although the times have been correlated to aircraft wing tests [2] they do not address the mechanism of fluid failure. To measure and understand the fluid mechanisms conducting to failure, the Anti-icing Materials International Laboratory (AMIL) developed a simplified test with a generic deicing propylene glycol-based fluid. The test consisted of pouring 400 mL of the generic deicing fluid on a 5 dm by 3 dm level flat plate where the plate edges were rimmed with insolated walls to make a waterproof open box.
2011-06-13
Technical Paper
2011-38-0035
Colin Hatch, Richard Moser, Roger Gent, Peter Hicks
The demand for low power ice protection systems and the introduction of further regulations for flight into known icing will stretch current technologies and the analytical tools required to support them. This paper considers an approach in the development of an analysis tool for the assessment of a combined electro-thermal and electro-mechanical deicing system. The tool development is part of a 4 year EU programme (project ‘HETEMS’ - Hybrid ElectroThermal and ElectoMechanical Simulation) and will include the icing wind tunnel testing of a hybrid deicing system to provide validation data. The various analytical components required by the system are presented and some of the issues in applying them are discussed. The tool will aim to provide both a 2D and 3D capability and allow both conceptual and detailed design strategies.
2011-06-13
Technical Paper
2011-38-0029
George A. Isaac, Monika Bailey, Faisal Boudala, Stewart G. Cober, Robert Crawford, Norman Donaldson, Ismail Gultepe, Bjarne Hansen, Ivan Heckman, Laura Huang, Alister Ling, Janti Reid, Marc Fournier
The Canadian Airport Nowcasting Project (CAN-Now) has developed an advanced prototype all-season weather forecasting and nowcasting system that can be used at major airports. This system uses numerical model data, pilot reports, ground in-situ sensor observations (precipitation, icing, ceiling, visibility, winds, etc), on-site remote sensing (such as vertically pointing radar and microwave radiometer) and off-site remote sensing (satellite and radar) information to provide detailed nowcasts out to approximately 6 hours. The nowcasts, or short term weather forecasts, should allow decision makers at airports such as pilots, dispatchers, de-icing crews, ground personnel or air traffic controllers to make plans with increased margins of safety and improved efficiency. The system is being developed and tested at Toronto Pearson International Airport (CYYZ) and Vancouver International Airport (CYVR).
2011-06-13
Technical Paper
2011-38-0104
Mariusz Kubryn, Robert Flemming, Ben Bernstein, Janusz Pietruszka
PZL Mielec is in the process of certificating the ice protection systems installed on the M28 turboprop aircraft so that customers of that aircraft may operate in icing conditions. The M28 airplane is derived from the Antonov An-28, which was certificated in Russia to their icing certification requirements many decades ago. The M28 is equipped with a lot of western equipment, including Pratt and Whitney Canada engines and Hartzell propellers, and now has a no-hazard certification for the use of the installed ice protection system. The M28 ice protection equipment includes wing and tail anti-icing, engine inlet anti-icing, propeller deicing, and wing strut deicing. These systems have undergone a series of development flight tests and icing wind tunnel tests. This paper presents an overview of the flight tests and wind tunnel tests conducted to date.
2011-06-13
Technical Paper
2011-38-0102
Thomas Reid, Guido S. Baruzzi, Isik A. Ozcer, Wagdi G. Habashi
The assessment of an unsteady approach for the simulation of in-flight electro-thermal de-icing using a Conjugate Heat Transfer (CHT) technique is presented for a NACA0012 wing and a swept wing. This approach is implemented in the FENSAP-ICE in-flight icing system, and provides simulation capabilities for the heat transfer and ice accretion phenomena occurring during in-flight de-icing with power cycling through several heater pads. At each time step, a thermodynamic balance is established between the water film, the ice layer and the solid domains. The ice shape is then modified according to ice accretion and melting rates. Numerical results show the complex interactions between the water film, the ice layer and the heating system. The NACA0012 validation test case compares well against one of the very few experimental de-icing test cases available in the open literature.
2011-06-13
Technical Paper
2011-38-0098
Austin Overmeyer, Jose Luis Palacios, Edward C. Smith, Roger Royer
Ultrasonic excitation has proven to provide ice interface transverse shear stresses exceeding the adhesion strength of freezer and wind tunnel ice to various metals, promoting instantaneous ice delamination. Prior proof-of-concept testing presented issues related to piezoelectric actuator cracking under ultrasonic tensile excitation, as well as actuator debonding from the host structure. The aim of this research is to provide solutions to the actuator reliability issues encountered during prior research and to perform rotor icing testing to validate the proposed solutions. Three different approaches are taken to solve the issues related with actuator failure during de-icing processes: custom-designed controllers to ensure the excitation of desired ultrasonic resonance modes, compression only driving of the actuator, and optimization of actuator thickness.
2011-06-13
Technical Paper
2011-38-0096
Shinan Chang
Electro-thermal deicing process was an unsteady heat transfer process including phase change. Based on the investigation of such a process, a code was developed to numerically simulate electro-thermal deicing process. Phase change was performed by an enthalpy method. A staircase approach was used to describe the variable ice thicknesses along the icing surface. The control volume method was adopted to discretize the governing equations. Tri-diagonal matrix method, alternating direction implicit method and block-correction technique were used to solve the discrete equations. Results of temperature distribution in this investigation were compared with experimental results of previous study. Their good agreements indicate the validity of our simulation. The effects of icing conditions, such as ambient temperature, liquid water content (LWC) and flight velocity, etc., were analyzed through a case. Some useful conclusions were achieved.
2011-06-13
Technical Paper
2011-38-0097
Roger J. Aubert, Jason Wright
As the technology in rotor deicing matures, more programs are willing to engage in the certification of their helicopters for flight into icing conditions. The S-92A™ helicopter, AW139, V-22, and EC225 aircraft have been certified/qualified recently and are illustrative examples of such engagement. The state-of-the-art configuration definition of rotor ice protection systems that have been introduced into the western rotorcraft manufacturer's production line has been limited to electro-thermal deicing systems. System configurations may use either chordwise or spanwise shedding schemes and could differ in design and operation. Regardless of the selected design configuration, an analysis of the required extent of protection coverage must be performed unless one has access to data offering sufficient similitude in terms of airfoil geometry and flight conditions.
2011-06-13
Technical Paper
2011-38-0085
Satya P. Chauhan, Melissa Roshon, W. D. Samuels, H. Nick Conkle, Elizabeth Berman, Mary Wyderski
Currently the U. S. Department of Defense (DoD) exclusively uses potassium acetate (KAc)-based runway deicing fluids (RDFs) to deice and anti-ice military runways and taxiways. Commercial airports predominantly use KAc, but some also use RDFs composed of KAc plus propylene glycol (PG) or urea plus PG. Conventional RDFs have environmental concerns due to toxicity as well as material compatibility problems such as corrosion of aircraft carbon brake-pad components, cadmium-plated landing gear, and airfield lighting fixtures. Under the Strategic Environmental Research and Development Program (SERDP), Battelle tested a series of patented - bio-based RDFs to address these issues. Tests showed that the Battelle RDFs met the mandatory Aerospace Material Specification (AMS) 1435 requirements. These new RDFs have reduced ecotoxicity compared to currently used RDFs and are compliant with all other environmental requirements.
2011-06-13
Technical Paper
2011-38-0084
Devon Seal, John Lengel, Timothy Arendt
Airports and airlines continue to work together to offer safe, reliable and cost-effective access to the world. There are many complex interactions at an airport, and addressing environmental issues is just one of the many functions an airport and airline must master. One of the key environmental issues affecting airports/airlines where frost or freezing conditions occur is the safe, efficient and environmentally protective management of deicer-affected storm water. Even those airports in the warmer southern United States have periods of freezing weather, whereby aircraft must be deiced. Although infrequent, the potential exists for adverse effects, and the need to establish a management plan based on risk is paramount.
2011-06-13
Technical Paper
2011-38-0078
Michael Papadakis, Paul Strong, See-Cheuk Wong
An experimental methodology for investigating the effects of anti-icing fluids is presented in this paper. A wing model was designed, fabricated, and instrumented for testing anti-icing fluids in a wind tunnel facility. In addition, a video capturing method was developed and used to document fluid behavior during simulated takeoff tests. The experiments were performed at the Wichita State University 2.13-m by 3.05-m (7-ft by 10-ft) wind tunnel facility with two pseudoplastic fluids representative of Type IV anti-icing fluids. The experimental data obtained included fluid wave propagation speeds, chordwise fluid thickness distributions as a function of time, and boundary layer velocity profiles for the clean and fluid contaminated wing model at select chordwise stations. During simulated takeoffs with initial fluid depths of either 4 mm or 2 mm, the fluids were observed to thin in the forward (upstream) regions of the wing model and accumulate in the aft regions.
Viewing 241 to 270 of 4795