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Technical Paper
2014-10-13
Dhaminda Hewavitarane, Sadami Yoshiyama, Hisashi Wadahama, Xin Li
Authors: Mr Dhaminda Hewavitarane (The University of Kitakyushu, Japan), Dr Sadami Yoshiyama (The University of Kitakyushu, Japan) , Mr Hisashi Wadahama (The University of Kitakyushu, Japan). Postal Address: The University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu City, Fukuoka Prefecture, 808-0135. Japan. Phone/Fax: (TEL)+81906953215, (MOBILE): +819036658310, (FAX)+81936953315 e-mail: hewavitarane_d@hotmail.com, yoshiyama@kitakyu-u.ac.jp Abstract: Background: In our modern industrial civilization, the vast majority of mechanical work is produced by heat engines. While the efficiency of heat engines has improved over the years, they remain relatively inefficient, loosing a significant portion of the input heat as waste heat. Waste heat recovery as a means of improving the overall efficiency of these engines in automotive applications has gained momentum in recent years. While many waste heat recovery (W.H.R) systems have been proposed and tested, the balance between, their efficiency, package size, integrability to the drive train and most importantly cost, have made most nonviable.
Technical Paper
2014-10-13
Karthikeyan N, Anish Gokhale, Narendra Bansode
In scooters, the Continuously Variable Transmission(CVT) is used to transmit the power from the engine to the wheels. The CVT transmission consists of a two pulleys connected to each other through a belt . The change in the transmission ratio is achieved due to the change in the pulley diameters. A centrifugal clutch is attached to the rear pulley to transmit the power to wheels once the engaging engine speed is reached. The heat is generated due to the belt slippage and the engagement of the centrifugal clutch. Excessive heating may damage the belt ,clutch and deteriorate its performance. The cooling of the belt , pulleys and the clutch is thus important for its safe operation. The cooling is achieved by the centrifugal cooling fan which forces the air over the belt, pulley and clutch. A clear understanding of the cooling system is important in designing the air flow path for clutch cooling of CVT housing. The efficiency of the cooling system depends on the quantity and direction of flow .
Technical Paper
2014-10-13
Manjushri M. Patil, Nitin P. Gokhale, Ashok T. Pise
Prediction of cylinder head temperature, using simulation techniques has been a topic of interest for engineers in the recent past. The work presented in the paper focuses on the temperature prediction part of the topic along with a methodology to correlate individual point data of the cylinder head based on field operating conditions. This paper details out the study done on a three cylinder stationary diesel engine with regards to distribution of temperature of the cylinder head bottom deck and other critical areas. The study is performed at various loads to examine the trends in these temperatures and provide an input to the estimation of the cylinder head life based on field operating conditions. In the first phase of the study a simulation model of the complete engine cooling circuit is prepared using 3D CFD software. Flow distribution and flow velocities are studied along with its variation with respect to cylinder location and channel dimensions. From above study is then used for further analysis where flow and heat transfer (conduction, convection) is solved simultaneously using CHT (conjugate heat transfer) simulation technique.
Technical Paper
2014-09-16
David Gras, Christophe Pautrel, Amir Fanaei, Gregory Thepaut, Maxime Chabert, Fabien Laplace, Gonzalo Picun
Power systems are continuously looking for high efficiency systems especially for high temperature applications where self-heating margin is very small. In applications such as Intelligent Power Modules (IPM), Motor Drives, and Power Inverters, high efficiency, high voltage and high temperature Silicon Carbide (SiC) and Gallium Nitride (GaN) power transistors are being used in several industries including aeronautics & aerospace, automotive, and down-hole. In this paper, we present a highly integrated, high-temperature solution for driving such power transistor. The solution is composed of the XTR26010 (High-Temperature Intelligent Gate Driver) with the XTR40010 (High-Temperature Isolated Two Channel Transceiver) for isolated gate drive, and XTR30010 (High-Temperature PWM Controller) with XTR2N0825 (High-Temperature 80V N-Channel Power MOSFET) for isolated power supply. XTR26010 is a high-temperature, high reliability isolated power transistor driver integrated circuit, designed with a high focus on offering a robust, reliable, compact and efficient solution for driving a large variety of high-temperature, high-voltage, and high efficiency power transistors.
Technical Paper
2014-09-16
Mark Donovan, Pedro Del valle
As aviation enters the future, new technologies and philosophies are required to keep up with ever changing demands and increased market competition. Aircraft designers are required to come up with new and innovative ways to optimise systems and improve efficiency. Onboard thermal management is an area that can take advantage of several new technologies to do just that. This paper is based on the development project “Advanced Thermal Management in Aeronautics” (ATMIA) and continues the analysis of the previous papers. Project ATMIA focuses on the use of Loop Heat Pipes (LHPs) in the aeronautical industry, specifically their onboard feasibility and the unique requirements found on an aeronautical platform such as those due to vibrations, gravitational forces and the need for disassembly due to maintenance. LHPs are passive two-phase devices that allow free-energy heat transportation between certain subsystems without needing additional power consumption. Their use in aeronautics is interesting as aircrafts have areas that produce excess heat that needs to be rejected and areas that require heat.
Technical Paper
2014-09-16
Andre Hessling
Reducing maintenance and improving safety for commercial aircraft can at times oppose each other. Advanced technologies in LED’s and Super-capacitors have the potential to reduce maintenance and improve safety for aircraft. By introducing LED’s and Super-capacitors the performance profiles of these technologies require a rethinking of the Lighting systems and equipment setups. Rewriting Lighting System requirements allow for greater design solutions which will provide better Lighting products to support operators which will in turn make them more profitable and improve safety over products that are flying today. Two examples are presented: an LED Landing Light and a Supercap based emergency light. 1) Aircrafts need adequate illumination for night time landing. Currently this requirement is met via high power halogen lamp or HID lights. Useful light for the pilot is a combination of intensity and direction. Too much light in undesired direction can cause excessive halation in adverse weather conditions forcing the pilots to shut down the lights entirely.
Technical Paper
2014-09-16
James H. Graham, Roger Dixon, Peter Hubbard, Ian Harrington
On future UAVs it is envisaged that the power requirements of all on-board electrical systems will increase. In most flight (mission) situations the installed power generation will have adequate capacity to operate the aircraft. It is possible that during abnormal situations the generators on-board may be forced to operate under very high load conditions. The main failure mechanism for a generator is overheating and subsequent disintegration of windings, hence the research problem being addressed here is to manage the loads upon the generator to prevent overheat. The research presented here summarises the modelling of the generator and formation of the load management system. Results are presented showing the system reallocating loads after a fault during flight, preventing overheat of the generators and successfully completing the mission.
Technical Paper
2014-09-16
Wei Wu, Yeong-Ren Lin, Louis Chow
W. Wu, Y.R. Lin, T. Mahefkey and L.C. Chow Department of Mechanical and Aerospace Engineering, University of Central Florida Orlando, FL 32816 In this presentation, we address the thermal management issues which limit the lifespan, specific power and overall efficiency of an air-cooled rotary Wankel engine used in Unmanned Air Vehicles (UAVs). Our goal is to eliminate hot spots in the engine housing and side plates by aggressive heat spreading using heat pipes. We demonstrate by simulation that, for a specific power requirement, with heat spreading and more effective heat dissipation, thermal stress and distortion can be kept to an acceptable level, even with air cooling. The maximum temperature dropped 79% (drop from 231oC to 129oC). The temperature difference (measure of temperature uniformity) decreased by 8.8 times (decrease from 159oC to 18oC) for a typical UAV engine. Our heat spreaders would not change the frontal area of the engine and should have a negligible impact on the installed weight of the propulsion assembly.
Technical Paper
2014-09-16
Gene Tu, Wei Shih, Walter Yuen PhD
In electronic systems, a heat sink is a necessary passive heat exchanger that cools a device by dissipating heat into the surrounding medium. For example, in computers, heat sinks are used to cool central processing units or graphics processors. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light emitting diodes (LEDs), where the heat dissipation ability of the basic device is insufficient to moderate its temperature. A heat sink is designed to maximize its surface area in contact with the cooling medium surrounding it, such as the air. Air velocity, choice of material, protrusion design and surface treatment are factors that affect the performance of a heat sink. Currently, relatively simple design methods are available for the design of conventional heat sink, determining the needed thermal resistance, material, fin efficiency for a specific heat duty. For practical applications, heat sinks are generally designed based on peak duty.
Technical Paper
2014-09-16
Alireza R. Behbahani, Alex Von Moll, Robert Zeller, James Ordo
Modern propulsion systems face challenges that require the aircraft and engine manufacturers to improve performance as well as reducing the Life Cycle Cost (LCC) throughout the life of a system which requires a more efficient, reliable, and advanced propulsion system. The concept of smart components for the engine / aircraft are aimed at actively controlling the engine and the aircraft to operate optimally to intelligently increase efficiency and system safely throughout the flight envelope / mission while meeting environmental challenges. This approach requires an integration and optimization, both at the local level and the system level, to reduce cost. Integrating subsystem models into a complete interactive system, one must optimize the platform using integrated system models. Model Based Design reduces cost and risk through Multi-Disciplinary System Simulation. This process involves defining, developing, and validating for key Integrated Propulsion, Power, and Thermal Management System capabilities.
Technical Paper
2014-09-16
Fan Frank Wang
Meeting Challenges of Using COTS Component Thermal Data in Aerospace Application Frank Fan Wang Crane Aerospace & Electronics Lynnwood, WA 98046, USA 425-743-8478 frank.wang@crane-eg.com Extended Abstract This article is about the issue of published thermal data from commercial off the shelf (COTS) component manufacturer. Use of commercial electronic components for aerospace applications has the benefit of technical advancement, cost reduction and scheduling. Effectively using commercial electronic components will enhance the performance of aerospace products. In most cases, the benefits of using commercial components can be concluded in three words: cheaper, better, and faster. However, some of the published electrical component thermal data can be confusing and misleading. Use without thorough understanding is risky. The thermal related information from the COTS component datasheets is one of the major issues that has troubled many aerospace electronics equipment packaging engineers for years.
Technical Paper
2014-09-16
Michael Ellis, William Anderson, Jared Montgomery
Under a program funded by the Air Force Research Laboratory (AFRL), Advanced Cooling Technologies, Inc. (ACT) has developed a series of passive thermal management techniques for cooling avionics. Many avionics packages are often exposed to environment temperatures much higher than the maximum allowable temperatures of the electronics. This condition prevents the rejection of waste heat generated by these electronics to the surrounding environment and results in significant ambient heat gain. As a result, heat must be transported to a remote sink. However, sink selection aboard modern aircraft is limited at best. Often, the only viable sink is aircraft fuel and, depending on mission profile, the fuel temperature can become too high to effectively cool avionics. As a result, the electronic components must operate at higher than intended temperatures during portions of the mission profile, which reduces component lifetime and significantly increases the probability of failure. To address this issue, ACT developed two passive thermal management approaches for avionics packages: heat pipe assemblies to reduce the internal temperature gradient and a Loop Heat Pipe (LHP) to transport thermal energy to alternative sinks.
Technical Paper
2014-09-16
Daniel Schlabe, Jens Lienig
The reduction of aircraft weight, fuel consumption, and hence CO2 emissions is a major goal of future aircraft designs. Efficient and light aircraft systems can considerably contribute to this target which, amongst others, has led to the development of More Electric Aircraft (MEA) in the past. Due to the increased demand of electrical power and the reduced usage or even totally absence of bleed air from the engines, novel types of cooling technologies and hence thermal management systems have been considered. Thermal Management Architectures (TMA) encompass air cycle machines, ram air channels, circulation and distribution of air flow, vapor compression cycles, cooling loops, as well as alternative heat sinks like skin heat exchangers. Together with highly integrated and complex TMAs, there is an increased degree of freedom in controlling the system. Optimal controller signals provided by a Thermal Management Function (TMF) are essential to improve system efficiency and to reduce system weight.
Technical Paper
2014-09-16
Jesse Miller, John Hoke, Frederick Schauer
An intercooler is a heat exchanger used to lower the temperature of compressed air exiting a turbocharger before entering the engine. Having an effective and reliable intercooler helps avoid engine knock while increasing engine power. An intercooler that does not transfer heat effectively or evenly, and has a high pressure drop causes inefficiencies and can damage the engine. This experiment tests two compact intercoolers designed for a small, high performance, knock limited engine. Both intercoolers use air-to-liquid cross flow heat exchangers with staggered fins. The intercoolers have one air entrance and four air exits as well as a water inlet and outlet. One intercooler uses internal baffles to help evenly distribute airflow. Two different setups are used to test the intercooler at steady versus unsteady airflow conditions. The first setup connects the four air outlets of the intercooler to a common restricted exit creating a constant back pressure which allows for steady airflow.
Technical Paper
2014-09-16
Philip Abolmoali, Javier A. Parrilla, Awatef Hamed
The optimal integration of vehicle subsystems is of critical importance in the design of future energy efficient fighter aircraft, characterized by megawatt-class thermal loads & power requirements1. The INVENT (INtegrated Vehicle ENergy Technology) program has been dedicated to this endeavor by modeling/simulation and optimization of thermal management, power generation & distribution, & actuation subsystems. Of these subsystems, the Thermal Management System (TMS) is responsible for supporting air & liquid-based cooling for avionics, cockpit, and miscellaneous thermal loads.. Electric power generation & distribution is provided by the Robust Electric Power System (REPS). Both subsystems operate in a highly complex, integrated environment. A reduction in overall system complexity by leveraging components from connected subsystems would be consistent with the spirit of intelligent systems integration and progress the state-of-the-art. In this paper, we present a reconfiguration of an archetypal closed-loop air cycle system for a modern fighter as an open-loop Brayton cycle gas generator that may operate interchangeably between refrigeration and auxiliary power modes.
Technical Paper
2014-09-16
Matthew Dooley, NIcholas Lui, Robb Newman, Clarence Lui
Complex, high-powered electronics used on modern aircraft generate large amounts of heat, and the complexity and energy demands only grow with each new generation of electronics. Commensurate heats sink capable of absorbing this load are the crucial element in an aircraft’s thermal management system, and so the capacities of heat sinks must evolve with this electronics growth. This paper presents an industry survey of conventional heat sinks in current use and then introduces and discusses potential advances in heat sink technologies. These technologies show significant promise to increase the capacity of thermal management systems on future aircraft and thereby unlock the full performance of next generation electronics.
Technical Paper
2014-09-16
Wei Wu, Yeong-Ren Lin, Louis C. Chow, Quinn Leland
W. Wu1, Y.R. Lin1, D. Zhao1, L.C. Chow1 and Q. Leland2 1 Department of Mechanical and Aerospace Engineering, University of Central Florida Orlando, FL 32816 2 Air Force Research Laboratory, Aerospace Systems Directorate Wright Patterson AFB, OH 45433 Background and Purpose The scaling laws of fans express basic relationships among the variables of volume flow rate, air density, rotational speed, fan diameter, and power. This makes it possible to compare the performance of geometrically similar fans in dissimilar conditions. The fan laws were derived from dimensionless analysis of the equations for volumetric flow rate, static pressure head, and power. The purpose of this study is to characterize a fan's performance characteristics at various rotational speeds and various ambient pressures, from 1 atm to 0.2 atm. The experimental results are compared to the fan scaling laws. Methodology A commercial brushless DC axial fan is chosen. It is run within a closed test loop. For various chosen ambient pressures and rotational speeds, the fan static pressure head, volumetric flow rate, and flow velocity were measured.
Technical Paper
2014-09-16
Travis E. Michalak
Numerous previous studies have highlighted the potential efficiency improvements which can be provided to aircraft thermal management systems by the incorporation of vapor cycle systems (VCS), either in place of, or in conjunction with, standard air cycle systems, for providing the needed refrigeration effect for cooling of aircraft equipment and crews. This paper will present the results of a cycle-based VCS control architecture as tested using the Vapor Cycle System Research Facility (VCSRF) in the Aerospace Systems Directorate of the Air Force Research Laboratory at Wright-Patterson Air Force Base. The VCSRF is a flexible, dynamic, multi-evaporator VCS which incorporates electronic expansion valves and a variable speed compressor to improve the flexibility of the control schemes that can be tested. This facility was designed and fabricated to allow testing of various VCS components and control schemes with the goal of reducing the risk of incorporating VCS into the thermal management systems of future advanced aircraft.
Technical Paper
2014-09-16
Pedro Del valle, Pablo Blazquez Munoz
Advance thermal systems are being developed to optimise the energy balance within aircraft. This is being done in parallel to the concept of the More Electrical Aircraft (MEA) which has been developing throughout the last decades. The objective of such complex systems is to use efficiently the hot and cold sources available within the air vehicle to reduce the engine fuel consumption. A reduction of electrical power consumption, minimisation of weight, optimisation of aircraft aerodynamics (for example RAM inlets area minimisation) and the reduction of bleed air from engine all result in a fuel consumption saving. Any thermal management system to optimise energy consumption implies complex and advanced systems. These require a high engineering effort to be designed and integrated within an aircraft due to the large quantity of variables and interfaces that need to be taken into account. Models and simulations are essential from the beginning of the system development and design phase.
Technical Paper
2014-09-16
Andrew Slippey, Michael Ellis, Bruce Conway, Hyo Chang Yun
Carbon fiber reinforced polymer (CFRP) composite material is a highly attractive structural material in applications where mass is critical. The carbon fiber matrix provides strength comparable to steel in a material with only about 25% of the density. In many instances, the CFRP sheet can also be made thinner than a metal sheet with similar mechanical properties, further increasing the mass savings. However, thermal challenges have arisen with the increased use of composites in applications where excess heat is being generated internally. In the area of electronics enclosures, traditional metal structures conduct and spread heat out over large external surfaces, but composites have poor thermal conductivity and act as insulators. The heat generated by components causes internal temperatures rise and has detrimental impact on the performance and reliability of the electronics. CFRP materials typically have thermal conductivities on the order of 5 W/m-K, while carbon steel is near 50 W/m-K and aluminum is near 200 W/m-K.
Technical Paper
2014-09-16
Shweta Sanjeev, Goutham Selvaraj, Patrick Franks, Kaushik Rajashekara
In a More Electric Aircraft, there is a need to integrate power electronics with the starter generator system. The power electronics operates in the hostile engine environment. This requires use of power devices and passive components that are capable of operating at high temperatures (200-250 C). Wide band gap materials such as Silicon-Carbide (SiC) and Gallium Nitride (GaN) are used as power devices to provide the power conversion at high temperature. In this project, a 50 kVA high temperature bi-directional converter provides the power conversion for starter generator system at 200 C, which can be directly mounted on the engine compartment. The converter is a three phase PWM active rectifier, based on SiC MOSFET. During starter mode, the converter acts as an inverter providing AC voltage to the motor to start the engine During generator mode it functions as an active rectifier converting the AC voltage to 540V DC (+/-270V DC). The DC output of the converter provides power to the platform’s HVDC loads, DC-AC inverter fed AC loads and 28V DC loads.
Technical Paper
2014-09-16
Matthew R. Cerny, Keith Joerger
This paper identifies critical and relevant variable/adaptive cycle turbine engine and propulsion subsystem technologies for future carrier-based naval aviation systems. A comprehensive evaluation of key technology drivers associated with the development and demonstration of advanced Adaptive Power and Thermal Management System (APTMS) technologies applicable to 6th Generation (Gen) DEW-capable platforms is addressed. Specifically, the paper explores energy optimization through dynamic mission based simulations of an advanced hybrid air cycle / vapor cycle APTMS architecture combining multiple traditionally federated subsystem functions including auxiliary power, environmental control, emergency power, and engine start. The Integrated Power Turbomachine (IPTM) under development by GE Aviation (GEA) is a critical component of the 6th Gen hybrid APTMS architecture, enabling a three-fold increase in design cooling capacity compared to current 5th Gen air dominance platforms, with a significant reduction in engine bleed extraction.
Standard
2014-07-17
To provide standard terminology and definitions with regard to ignition systems for spark-ignited internal combustion engines.
Standard
2014-07-11
This document specifies that black is the only color that can be used for the insulator at the bottom of the base of T-1 and T-1 ¾ Flanged Base lamps.
Standard
2014-07-11
This SAE Aerospace Information Report (AIR) provides a general overview of oxygen systems for general aviation use. Included are a brief review of the factors and effects of hypoxia, system descriptions, and mission explanations for system or component selection, and techniques for safe handling of oxygen distribution systems.
Magazine
2014-07-10
Off-highway engines advance beyond Tier 4 With Tier 4 Final/Stage IV needs met, engine OEMs direct their focus and competitive energies toward optimizing competitive solutions. At the same time, they need to keep a weather eye out for future regulations, which many expect. Autonomous vehicle challenges span many fields Many of the challenges faced by military and commercial design teams are similar. Racket busters With a quiet cab at the top of many tractor buyers' wish lists, agricultural equipment manufacturers are pursuing every opportunity possible to shed decibels.
Article
2014-07-08
The supplier introduced its new seating style to accommodate comfort and functionality.
Book
2014-07-08
This 2014 edition of the Automotive Cockpits and Dashboards Report is the latest in the series of reports by Supplier Business looking at trends and developments in the vehicle cockpit space. Over time we have seen many changes in terms of the design and structure of the main modules and components that go to make up the dashboard and cockpit element of the vehicle’s interior. In particular the increasing level of in-vehicle connectivity has caused interior designers to rethink the layout and content of the dashboard and center console. In this report the main trends and developments are highlighted, with particular reference to examples of the way in which the industry has responded to the challenge. The strongest influence on the vehicle’s cockpit and dashboard continues to be the requirement for in-vehicle connectivity. Consumer demand for seamless connectivity between home, office and vehicle dominates the cockpit’s interior design and structure. The technology required to provide the level of connectivity demanded by users is increasingly complex and, by necessity, has to embrace advanced driver active safety systems (ADAS) and the anticipated development of semi-autonomous and ultimately, fully autonomous vehicles.
Standard
2014-07-01
This SAE Aerospace Information Report (AIR) provides Nuclear, Biological and Chemical (NBC) protection considerations for environmental control system (ECS) design. It is intended to familiarize the ECS designer with the subject in order to know what information will be required to do an ECS design where NBC protection is a requirement. This is not intended to be a thorough discussion of NBC protection. Such a document would be large and would be classified. Topics of NBC protection that are more pertinent to the ECS designer are discussed in more detail. Those of peripheral interest, but of which the ECS designer should be aware are briefly discussed. Only radiological aspects of nuclear blast are discussed. The term CBR (Chemical, Biological, and Radiological) has been used to contrast with NBC to indicate that only the radiological aspects of a nuclear blast are being discussed. This is actually a more accurate term to describe the subject of this paper, but NBC has become more widely used in the aircraft industry.
Technical Paper
2014-06-30
Bryce Gardner, Tiago Macarios
Abstract Speech transmissibility is a critical factor in the design of public address systems for passenger cabins in trains, aircraft and coaches. Speech transmissibility is primarily affected by the direct field, early low order reflections, and late reflections (reverberation) of the source. The direct and low order reflections are affected by the relative location of speakers and seats as well as the acoustic properties of the reflecting walls. To properly capture these early reflections, measures of speech transmissibility typically require time domain information. However, another important factor for speech transmissibility is background noise due to broadband exterior sources such as a flow noise sources. The background noise is typically modeled with broadband steady state assumptions such as in statistical energy analysis (SEA). This works presents an efficient method for predicting speech transmissiblity by combining ray tracing with SEA. In this method, the direct field and low order reflections are modelled using raytracing, while the reverberant field and background noise are modelled using SEA.
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