Showing papers on "Propulsion published in 2005"

Topological overview of hybrid electric and fuel cell vehicular power system architectures and configurations

Abstract: This paper discusses the operational characteristics of the topologies for hybrid electric vehicles (HEV), fuel cell vehicles (FCV), and more electric vehicles (MEV). A brief description of series hybrid, parallel hybrid, and fuel cell-based propulsion systems are presented. The paper also presents fuel cell propulsion applications, more specific to light-duty passenger cars as well as heavy-duty buses. Finally, some of the major fundamental issues that currently face these advanced vehicular technologies including the challenges for market penetration are highlighted.

Propulsion of a Molecular Machine by Asymmetric Distribution of Reaction Products

Abstract: A simple model for the reaction-driven propulsion of a small device is proposed as a model for (part of) a molecular machine in aqueous media. The motion of the device is driven by an asymmetric distribution of reaction products. The propulsive velocity of the device is calculated as well as the scale of the velocity fluctuations. The effects of hydrodynamic flow as well as a number of different scenarios for the kinetics of the reaction are addressed.

Superconductively levitated transport system - the SupraTrans project

Abstract: SupraTrans is an innovative transportation concept based on the principle of superconductive magnetic levitation. The aim of the project is to create a fully working prototype, which proves its ability for passenger transport by explicit consideration of the compatibility between systems for propulsion, safety, positioning, power supply, transport logistics and the levitation system itself. The SupraTrans technology uses the flux pinning in high temperature superconductors (HTS) to stabilize the lateral and vertical position of the vehicle on the magnetic track. This self-stabilizing system is the main advantage of the superconductive levitation in comparison to all other levitation systems, which need electronic control and power to keep a constant distance between the train and the track.

A Non-Linear Model for the Longitudinal Dynamics of a Hypersonic Air-breathing Vehicle

Abstract: : A non-linear, physics-based model of the longitudinal dynamics for an air-breathing hypersonic vehicle is developed. The model is derived from first principles and captures the complex interactions between the propulsion system, aerodynamics, and structural dynamics. Unlike conventional aircraft, hypersonic vehicles require that the propulsion system be highly integrated into the airframe. Furthermore, hypersonic aircraft tend to have very lightweight, flexible structures that have low natural frequencies. Therefore, the first bending mode of the fuselage is important as its deflection affects the amount of airflow entering the engine, thus influencing the performance of the propulsion system. The equations of motion for the flexible aircraft are derived using Lagrange's Equations. The equations-of-motion capture inertial coupling effects between the pitch and normal accelerations of the aircraft and the structural dynamics. The linearized aircraft dynamics are shown to be unstable, and in most cases, exhibit non-minimum, phase behavior. The linearized model also indicates that there is an aeroelastic mode that has a natural frequency more than twice the frequency of the fuselage bending mode. Furthermore, the short-period mode is very strongly coupled with the bending mode of the fuselage.

The performance of a 5 MW high temperature superconductor ship propulsion motor

Abstract: A 5 MW, 230 RPM, 6-pole high temperature superconductor (HTS) ship propulsion motor is presently under test at the Center for Advance Power Systems (CAPS). This paper provides a summary of the key design features of the motor, predicted performance, factory test results and extended test results to date at CAPS. This motor was designed and built under the U.S. Navy's Office of Naval Research (ONR) funding (Contract #N00014-02-C-0190) to address the next generation of electric ship propulsion systems. HTS motors are characterized by high power density, quiet operation and high efficiency. HTS air-core motors have unique electrical characteristics and therefore require dynamic testing to validate all modes of operation. The test program at CAPS is designed to address dynamic performance and simulation of this class of propulsion motor. The motor has been operated at 5 MW load for over 3 hours at CAPS.

Biomechanical aspects of peak performance in human swimming

Abstract: Peak performances in sport require the full deployment of all the powers an athlete possesses. How factors such as mechanical power output, technique and drag, each individually, but also in concert, determine swimming performance is the subject of this enquiry. This overview of swimming biomechanics focuses on three performance factors: (i) generation of propulsion in water; (ii) drag encountered by the body during swimming; and (iii) propulsive efficiency. Theoretical considerations will be put to use by predicting individual power requirements for swimming a world record in the 50 m freestyle based on experimental data.

High power density superconducting motor for all-electric aircraft propulsion

Abstract: NASA conducts and funds research to advance the state of the art in aeronautics, including improvements in aircraft design leading to enhanced performance in areas such as noise, emissions, and safety. A particular initiative involves development of an all-electric aircraft requiring significant improvements in certain technologies. NASA has started a new project with one of the objectives being the development of enabling technologies for an all-electric aircraft. Electrical aeropropulsion requires the design of more compact and efficient electrical motors. In order to increase the power density, the weight/size must be minimized and the air gap flux density must increase significantly: the use of superconducting materials is an obvious choice. Existing HTS motors are proof-of-principle demonstrators and exhibit power densities lower than 1 HP/lb, which is too low to be considered in mobile systems. This paper deals with a preliminary electromagnetic design of a 200 HP high temperature superconducting motor optimized in terms of power density. The presented configuration is a synchronous motor with a nonconventional topology enhanced by HTS bulk material. The design targets the Cessna 172 propulsion requirements that are 200 HP at 2700 RPM.

Five-phase permanent magnet motor drives for ship propulsion applications

Abstract: Multi-phase machines are very good candidates for ship propulsion application. In this paper, first a literature survey on the work accomplished in the area of multi-phase, split-phase and dual stator machines are presented. In the rest of the paper, additional degrees of freedom in multi-phase permanent magnet machines are employed to improve the overall performance of the system. Among all, the paper suggests and focuses on four significant features of multi-phase machines. First, the ability of injecting harmonic of currents in the motor and improving the torque production capability is discussed. Second, better torque and flux adjustment in DTC controlled multi phase motor is presented. Third, fault resilient current control of multi phase drive under loss of phases is examined. Finally the possibility of controlling multi motors through a single inverter is pointed out. The five phase permanent magnet motor is considered in this paper as an example. However the concept can be extended to higher number of phases.

Engine power extraction control system

Abstract: An engine power extraction control system controls the main propulsion engines and the electrical machines that are coupled thereto to supply an appropriate amount of aircraft thrust and electrical energy to the aircraft. The engines and electrical machines are also controlled so that the propulsion thrust that is generated is split between the various turbines in the main propulsion engines to maintain an adequate surge margin and to minimize residual thrust generation.

More electric aircraft starter-generator multi-speed transmission system

Abstract: A turbofan gas turbine propulsion engine includes a multi-speed transmission between the high pressure and low pressure turbines and associated high pressure and low pressure starter-generators. The multi-speed transmission reduces the operating speed range from the low pressure turbine to its associated starter-generator, and is configurable to allow the starter-generator associated with the low pressure turbine to supply starting torque to the engine.

Fundamentals of Jet Propulsion with Applications

Abstract: This introductory 2005 text on air-breathing jet propulsion focuses on the basic operating principles of jet engines and gas turbines. Previous coursework in fluid mechanics and thermodynamics is elucidated and applied to help the student understand and predict the characteristics of engine components and various types of engines and power gas turbines. Numerous examples help the reader appreciate the methods and differing, representative physical parameters. A capstone chapter integrates the text material into a portion of the book devoted to system matching and analysis so that engine performance can be predicted for both on- and off-design conditions. The book is designed for advanced undergraduate and first-year graduate students in aerospace and mechanical engineering. A basic understanding of fluid dynamics and thermodynamics is presumed. Although aircraft propulsion is the focus, the material can also be used to study ground- and marine-based gas turbines and turbomachinery and some advanced topics in compressors and turbines.

Modeling for Control of a Generic Airbreathing Hypersonic Vehicle

Abstract: The unique airframe-engine configuration of airbreathing hypersonic flight vehicles (AHFV) pose a significant challenge for design of controllers for these vehicles. The Airframe-engine configuration, the wide range of speed and the extreme flight conditions result in significant coupling among various dynamics and modeling uncertainties. There is almost a complete absence of models that adequately include and quantify the unique attributes for this class of vehicles. This paper describes a high-fidelity CFD-based model of a full scale generic airbreathing hypersonic flight vehicle under development at the Multidisciplinary Flight Dynamics and Control Laboratory (MFDCLab, www.calstatela.edu/centers/mfdclab) at California State University, Los Angeles (CSULA). The vehicle (CSULA-GHV), which has an integrated airframe-propulsion system configuration, resembles an actual test vehicle. The vehicle is specifically designed to study the challenges associated with modeling and control of airbreathing hypersonic vehicles and to investigate and quantify the couplings between the aerodynamics, the propulsion system, the structural dynamics, and the control system. The configuration of the vehicle and its dimensions are developed based on 2-D compressible flow theory, and a set of mission requirements broadly accepted for a hypersonic cruise vehicle intended for both space access and military applications. Analytical aerodynamic calculations are conducted assuming a cruising condition of Mach 10 at an altitude of 30 km. The 2-D oblique shock theory is used to predict the shock wave angles, the pressure on the frontal surface, and the Mach number at the engine inlet. The scramjet engine is simply modeled by a 1-D compressible flow with heating. The exit flow is modeled using 2-D expansion wave theory to predict the pressure on the rear surface. The unique aspect of this study is the use of coupled simulations using multi-physic software in conjunction with theory enabling quantification of the couplings which are broadly ignored in models used for control system design. Simulation results developed to date are presented.

Vertical take-off and landing (VTOL) aircraft with distributed thrust and control

Abstract: An aircraft having a vertical take-off and landing (VTOL) propulsion system. The aircraft includes a fuselage, the VTOL propulsion system, at least one forward thruster, a power source used for both the VTOL propulsion system and forward thruster, fore and aft wings and a plurality of spars attached to and spanning the space between the two wings. The VTOL propulsion system includes a plurality of VTOL cells (including a motor, motor controller, and propeller) attached in a spaced relation along each spar. The VTOL cells are used exclusively for vertical flight or hovering and are powered down as the aircraft develops forward flight velocity and corresponding wing lift. During forward flight the VTOL propellers are articulated to allow the aircraft to take on a low drag configuration. The present invention is suitable for use in manned or un-manned aircraft of any scale.

Opposed Piston Opposed Cylinder (opoc) Engine for Military Ground Vehicles

Abstract: An extremely lightweight opposed piston opposed cylinder (opoc) Diesel engine is under development by FEV Engine Technology under a Defense Advanced Research Projects Agency (DARPA) program. FEV and Advanced Propulsion Technologies (APT) were asked by the U.S. Army Tank Automotive Research Development and Engineering Center (TARDEC) to modify this engine for heavy-truck applications. Analyzing the two stroke scavenging, the side-injection combustion, and the structure of the key components shows the potential of the opoc concept. It is predicted for the 465 kW (650 hp) opoc truck engine: • Specific power of the dry engine ∼ 2kW/kg (1.2 hp/lb) • Engine Height ∼ 40 cm (16 in) • Best Efficiency at two sweetpoints ∼ 206 g/kWh (0.339 lb/hph).

Electric ship power system integration analyses through modeling and simulation

Abstract: The Center for Electromechanics (CEM) at the University of Texas is engaged in the development of a comprehensive power system model in order to address several challenging issues facing the development of a viable and effective integrated power system architecture for future naval platforms. The power system under consideration reflects the notional DD power system architecture and is developed in the Matlab/Simulink environment. System components such as motors and generators are modeled using parameters based on actual machine design and analysis work performed at CEM. Simulation results of models including permanent-magnet propulsion motors and generators with simple reconfiguration scenarios simulating loss and recovery of power to propulsion and vital loads are presented.

HTS motors in aircraft propulsion: design considerations

Abstract: Current high temperature superconducting (HTS) wires exhibit high current densities enabling their use in electrical rotating machinery. The possibility of designing high power density superconducting motors operating at reasonable temperatures allows for new applications in mobile systems in which size and weight represent key design parameters. Thus, all-electric aircrafts represent a promising application for HTS motors. The design of such a complex system as an aircraft consists of a multi-variable optimization that requires computer models and advanced design procedures. This paper presents a specific sizing model of superconducting propulsion motors to be used in aircraft design. The model also takes into account the cooling system. The requirements for this application are presented in terms of power and dynamics as well as a load profile corresponding to a typical mission. We discuss the design implications of using a superconducting motor on an aircraft as well as the integration of the electrical propulsion in the aircraft, and the scaling laws derived from physics-based modeling of HTS motors.

More electric aircraft power transfer systems and methods

Abstract: A turbofan gas turbine propulsion engine includes a system to transfer power from the low pressure turbine to the high pressure turbine and/or extract additional load from the low pressure turbine during certain turbofan engine operational conditions. The systems include a hydrostatic power transfer system that includes a hydraulic pump and a hydraulic motor coupled to the low pressure and high pressure turbine, respectively. The systems additionally include a mechanical and electrical load shifting/loading sharing systems that use clutches and gear assemblies to share and/or shift load between the turbines.

Design and control of a linear propulsion system for an elevator using linear switched reluctance motor drives

Abstract: Linear switched reluctance motor (LSRMs) for primary propulsion of a ship elevator is proposed and investigated in this paper. To achieve the stated objective, a new type of LSRM is proposed with twin stators and a translator between them with no back iron in the translator. The proposed configuration of the LSRM is designed, simulated and analyzed and compared to traditional LSRMs. The number of LSRM propulsion subsystems required is studied with a view to minimize their weights and an optimization study for that purpose is developed. Unique placement of the LSRM propulsion systems on the elevator is presented. Six sets of asymmetric bridge converters are chosen to drive the designed LSRM endowing it with high fault tolerance to the system. The propulsion force is generated using one phase or multi-phase excitation. In order to reduce force pulsations, a major requirement in elevators, controlled multi-phase excitation using one of the known force distribution functions (FDF) is an acceptable solution. The currently available FDFs are able to reduce the force pulsations but are not able to meet the peak force command is proven in this paper. Consequently, the speed and position control do not meet even the elementary performance requirements any more. A new FDF is proposed and presented to overcome the problem caused by the conventional FDF in this paper. The control system with the proposed FDF is derived and integrated for speed and position control. Extensive simulation results prove that the proposed LSRM with the new FDF exhibits superior performance and it is believed that it may be suitable for the ship elevator application

Gas-powered tip-jet-driven tilt-rotor compound VTOL aircraft

Abstract: A tilt-rotor compound VTOL aircraft has a multiple-flow thrust generator(s) comprising a gas-powered tip-jet driven rotor(s) having a thrust-augmentation ratio of at least two; that tilts about the aircraft's pitch axis wherein the rotor's plane of rotation is substantially horizontal for VTOL operations and the rotor's plane of rotation is substantially vertical forward flight operations. A relatively small fixed-wing sustains the aircraft during forward flight. Compressed exhaust gas from the fan-jet engine(s) is ducted to a manifold having valves which control power to the multiple-flow thrust generator(s) and to the jet exhaust nozzle(s) as supplemental thrust for forward propulsion and yaw control. The manifold also serves to distribute compressed gas to the dead engine side of the aircraft in the event of a dead engine emergency, and to reaction jets for attitude control during VTOL operations. Thus this tilt-rotor aircraft is more efficient, faster, immensely lighter, less complex and less expensive to purchase and maintain than its shaft-driven counterparts.

The SMART-1 Hall Effect Thruster Around the Moon: In Flight Experience

Abstract: Onboard the ESA SMART-1 spacecraft, (Small Mission for Advanced Research in Technology), the primary Electric Propulsion Subsystem (EPS) operates since the 30 th September 2003, allowed the capture by the Moon on the 15 th of November 2004 and finally the propulsion pushes the spacecraft to the operational orbit around the Moon on 27 th February 2005. The total in-flight accumulated hours of the thruster is about 5000 hours. And more than 800 times, the EPS was started. The first comment gained from the in-flight experience is that the EPS availability to perform the thrust function is recorded as 100%. One shall in addition point out that this performance was obtained even during the successive crossing of the Van Allen radiation belts. The particular orbit followed by SMART-1 to reach the Moon, to be captured and to reaches the operational Moon orbit, has fully confirmed the suitability of the Hall effect thruster to perform such high sensitive orbit maneuvers near the capture. EPS Contractor, ESTEC, and EPS manufacturer, SNECMA MOTEURS, will present in detail the major's performances of the complete electric propulsion system, with respect to the long life duration achieved. The main feature of the SMART-1 system is its variable power supply. The PPS ® -1350-G Hall Effect plasma Thruster and its Power processing unit, were developed in the frame of the CNES Stentor Program. Results of the in flight EPS includes the behavior of the robust bang-bang xenon pressure regulation for the input pressure and variable electrical power supply. This paper describes the performance results of the PPS ® -1350-G firing in space environment. It discusses also the particular behavior of the floating potential of the thruster with respect to the satellite orbital position and its sun incidence along years. The successful results obtained support the first technological experience objective of the SMART-1 mission. The performance in term of thrust or total impulse is discussed as well as the main lessons learned. These new features of primary electric propulsion subsystem and especially the low-power start-up and variable power features can be also a significant added value for any commercial application using electric propulsion for station-keeping and/or orbit transfer. The mission of the EPS, completed now, ended after performing a one and half month maneuver dealing with the increase of the orbital life by one more year.

Self-propelled harvesting machine

Abstract: A self-propelled harvesting machine having an internal combustion engine, a propulsion system that can be operated to cause the harvesting machine to move across a field with a propulsion speed, a crop material pick-up device for picking up the crop material from a field, a crop material processing device for processing the crop material that has been picked up, a control unit for specifying the speed of the internal combustion engine, and a through-put measurement device for determining the through-put of the harvesting machine. The control unit can be operated to vary the speed of the internal combustion engine depending on the signal from the through-put measurement device. In this manner the RPM of the internal combustion engine that is most favorable in terms of fuel consumption and that corresponds to the power to be applied at a given through-put can be specified.

Ceramic Matrix Composites: A Challenge in Space-Propulsion Technology Applications

Abstract: Various technology programs in Europe are concerned, besides developing reliable and rugged, low-cost, throwaway equipment, with preparing for future reusable propulsion technologies. One of the key roles for realizing reusable engine components is the use of modern and innovative materials. One of the key technologies that concerns various engine manufacturers worldwide is the development of fiber-reinforced ceramics—CMCs (ceramic matrix composites). The advantages for the developers are obvious–the low specific weight, the high specific strength over a large temperature range, and their great damage tolerance compared with monolithic ceramics make this material class extremely interesting as a construction material. Over the past few years, the EADS-ST Company (formerly DASA) has, together with various partners, worked intensively on developing components for hypersonic engines and liquid rocket propulsion systems. In the year 2000, various hot-firing tests with subscale (scale 1:5) and full-scale nozzle extensions were conducted. In this year, a further decisive milestone was achieved in the sector of small thrusters, and long-term tests served to demonstrate the extraordinary stability of the C/SiC material. Besides developing and testing radiation-cooled nozzle components and small-thruster combustion chambers, EADS-ST worked on the preliminary development of actively cooled structures for future reusable propulsion systems. In order to get one step nearer to this objective, the development of a new fiber composite was commenced within the framework of a regionally sponsored program. The objective here is to create multidirectional (3D) textile structures combined with a cost-effective infiltration process. Besides material and process development, the project also encompasses the development of special metal/ceramic and ceramic/ceramic joining techniques as well as studying and verifying nondestructive investigation processes for the purpose of testing components.

Modeling and Testing of a Biomimetic Flagellar Propulsion Method for Microscale Biomedical Swimming Robots

Abstract: Medical applications are among the most impactful areas of microrobotics. The ultimate goal of medical microrobots is to reach currently inaccessible areas of the human body and carry out a host of complex operations such as minimally invasive surgery (MIS), highly localized drug delivery, and screening for diseases at their very early stages. Miniature, safe and energy efficient propulsion systems hold the key to maturing this technology but they pose significant challenges. In this paper, authors propose a new type of propulsion inspired by the motility mechanism of prokaryotic microorganisms. The perfomance of this propulsive mechanism is estimated by modeling the dynamics of the motion. Analyzing key parameters such as linear velocity and efficiency, the optimum design of propulsion mechanism for miniatue robots is demonstrated. In order to validate the theoretical result for flagellar proplusion, a scaled up prototype of the swimming robot is fabricated and characterized in silicone oil using the Buckingham PI theorem for scaling. The proposed propulsion method is for the swimming robots which is intended to swim in low velocity biofluids. Potential target regions to use these robots include eyeball cavity, cerebrospinal fluid and the urinary system.

5 MW High Temperature Superconductor Ship Propulsion Motor Design and Test Results

Abstract: American Superconductor has designed, built, tested and delivered to the U.S. Navy's Office of Naval Research (ONR) a 5MW, 230-RPM, 6-pole high temperature superconductor (HTS) ship propulsion motor. The motor uses an air core armature winding and first generation HTS wire (BSCCO-2223) field winding. The goal of the motor development project was to validate the technologies required to design and build larger HTS ship propulsion motors, as well as to develop a motor production process that streamlines development time and minimizes cost. A commercial variable frequency drive is used to power the motor. The HTS field winding is cooled with G-M coolers with gaseous helium as the cooling medium in a closed cycle. The armature is cooled by MideP. The motor was delivered to the U.S. Navy in July 2003 and met or exceeded requirements in operation (up to the facility's testing limit of 2.5MW). The motor demonstrated both full torque and full speed operation in separate tests.