Abstract: Schemes have been suggested for transferring energy from Earth-to-space, space-to-Earth, and space-to-space using high-power microwave (HPM) beams. All use power beaming. Microwave beams have been studied for propelling spacecraft for launch to orbit, orbit raising, launch from orbit into interplanetary and interstellar space, and deployment of large space structures. The microwave thermal rocket, called the ldquomicrowave thermal thruster,rdquo is a reusable single-stage vehicle that uses an HPM beam to provide power to a heat-exchanger propulsion system, with double the specific impulse of conventional rockets. Orbital missions include orbit raising and space solar power. Microwave-propelled sails are a new class of spacecraft that promises to revolutionize future space probes. Experiments and simulations have verified that sails riding beams can be stable on the beam for conical sail shapes. Beam-driven sail flights have now demonstrated the basic features of the beam-driven propulsion. Beams can also carry angular momentum and communicate it to a sail to help control it in flight. An early mission for microwave space propulsion is dramatically shortening the time needed for sails to escape Earth's orbit. A number of missions for beam-driven sails have been quantified for high-velocity mapping of the outer solar system, Kuiper Belt, the Heliopause, and the penultimate interstellar precursor mission. For large HPM systems at fixed effective isotropic radiated power, minimum capital cost is achieved when the cost is equally divided between antenna gain and radiated power. This is a driver when considering design of power-beaming systems such as interstellar Beacons, which the Search for Extraterrestrial Intelligence is searching for. Much of the technical means for these applications are already in hand. Microwave and millimeter-wave array antennas are already in use for astronomy; sources at high frequencies are being developed for fusion and the military. Development of high-power arrays is needed. A synergistic way to develop a space power-beaming infrastructure is incremental buildup, addressing lower power applications first, and then upgrading.

Abstract: Linear switched reluctance motors (LSRMs) for the primary propulsion of a ship elevator is proposed and investigated for the first time 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, analyzed, compared with traditional LSRMs, and verified by experimental measurements. 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. The propulsion force is generated using one phase or multiphase excitation. To reduce propulsion force pulsations, a major requirement in elevators, controlled multiphase excitation using one of the known force distribution functions (FDF) is an acceptable solution. In this paper, it is proved that the currently available FDFs are able to reduce the force pulsations but are not able to meet the peak force command for the system. Consequently, the velocity and position control do not meet even the elementary performance requirements any more. A new FDF is proposed in this paper and presented to overcome the problem caused by a conventional FDF. The control system with the proposed FDF is derived and integrated into velocity and position controllers. Extensive dynamic simulation and experimental verification of the proposed LSRM with the novel FDF is proved to give superior performance in this paper. Such high performance capable of meeting vertical elevator applications is demonstrated.

Abstract: A hybrid propulsion and energy management system for use in marine vessels and other variable demand propulsion applications monitors and draws energy from various energy sources dynamically to implement multiple operating modes and provide efficient system operation across a range of propulsive demands, altering the operation and output of various energy sources in response to propulsive load demands, hotel loads and auxiliary energy demands. The propulsion system incorporates at least two propulsive sources, including at least one main propulsive engine and at least one motor-generator unit arranged to drive a common output shaft, and the energy management system dynamically shifts operation of each of the two sources to satisfy propulsive demands. The main propulsive engine and the motor-generator unit are capable of driving the common output shaft both independently and simultaneously. The motor-generator unit(s) are available to operate either as a motor driving the output shaft or as a generator supplying energy to the energy distribution system.

Abstract: This thesis investigates the hydrodynamic effects of biologically-inspired leading-edge tubercles. Two complementary studies examine the performance of three-dimensional hydrofoils based on the pectoral flippers of the Humpback Whale (novangilae megaptera). The first study uses a static foil, with application to conventional control surfaces– such as rudders or dive planes–found on marine vehicles. The second study uses a dynamic foil, with application to flapping foil propulsion. The lift and drag characteristics of foils with and without tubercles are compared using force measurements from experiments conducted in a water tunnel at four Reynolds numbers between 4.4 × 10 and 1.2 × 10. Results from these experiments indicate the foils stall from the trailing edge in the range of Reynolds numbers tested. Stall was delayed on the foil with tubercles; maximum lift was reduced in all cases but the highest Re. PIV flow visualization at Re = 8.9 × 10 4 showed flow separation at the trailing edge of both foils as attack angle was increased, confirming that the foils were in trailing edge stall. Surface normal vorticity in ensemble averaged flow fields showed distinct pairs of opposite sign vortical structures being generated by the tubercles, providing some insight into the fluid dynamic mechanism that leads to changes in the performance of a foil with tubercles. Tubercles were used on a flapping foil for the first time. Mean thrust coefficient, CT , power coefficient, CP , and efficiency, η, were measured over a wide parametric space. The maximum thrust coefficient and efficiency measured using the smooth control foil were CT = 3.511 and η = 0.678. The maxima using the tubercled test foil were CT = 3.366 and η = 0.663. In general, the foil with tubercles performed worse than the control, and this performance deficit grew with increased loading. These results suggest that the vortical structures generated by the tubercles interfere with the thrust wake generated by flapping, ultimately degrading performance. Thesis Supervisor: Alexandra H. Techet Title: Associate Professor of Mechanical and Ocean Engineering

Abstract: Traditionally, electric generators, driven by an aircraft's main propulsion engines or by a gas turbine (GT) auxiliary power unit (APU), have supplied the electrical needs of commercial aircraft. In flight, the marginal efficiency of electric power generated by the main engines and their generators is at most 30-40%, whereas on the ground with the engines shut off, the average fuel efficiency of the turbine-powered APU is typically less than 20% and also has undesirable noise and gaseous emissions. As environmental concerns mount, aircraft manufacturers and others are challenged to reduce fuel consumption while simultaneously reducing emissions. Hence, there is a very strong interest in developing fuel cells for aerospace applications. In this article, we report the study results of usingsolid oxide fuel cells (SOFCs) in combination with a GTas a hybrid APU system for a commercial aircraft. The purpose of this feasibility study is to investigate the potential use of fuel-cell-based APUs for onboard power generation in future "more-electric" commercial aircraft. In this article, the modeling of the major components of the SOFC-GT power generation system, summary of the findings, challenges, and final recommendations are presented.

Abstract: A propulsion system for a vertical take-off and landing ducted fan aerial vehicle is provided, the propulsion system comprising an internal combustion engine, an electric motor that comprises a motor generator, a motor drive and a battery. The motor drive and battery are integrated into the aerial vehicle and provide power to the ducted fan aerial vehicle. The electric motor may comprise a ring motor generator. In operation, this dual propulsion system serves as a weight-efficient option to allow for two sources of power on a ducted fan unmanned aerial vehicle.

Abstract: Meeting future goals for aircraft and air traffic system performance will require new airframes with more highly integrated propulsion. Previous studies have evaluated hybrid wing body (HWB) configurations with various numbers of engines and with increasing degrees of propulsion-airframe integration. A recently published configuration with 12 small engines partially embedded in a HWB aircraft, reviewed herein, serves as the airframe baseline for the new concept aircraft that is the subject of this paper. To achieve high cruise efficiency, a high lift-to-drag ratio HWB was adopted as the baseline airframe along with boundary layer ingestion inlets and distributed thrust nozzles to fill in the wakes generated by the vehicle. The distributed powered-lift propulsion concept for the baseline vehicle used a simple, high-lift-capable internally blown flap or jet flap system with a number of small high bypass ratio turbofan engines in the airframe. In that concept, the engine flow path from the inlet to the nozzle is direct and does not involve complicated internal ducts through the airframe to redistribute the engine flow. In addition, partially embedded engines, distributed along the upper surface of the HWB airframe, provide noise reduction through airframe shielding and promote jet flow mixing with the ambient airflow. To improve performance and to reduce noise and environmental impact even further, a drastic change in the propulsion system is proposed in this paper. The new concept adopts the previous baseline cruise-efficient short take-off and landing (CESTOL) airframe but employs a number of superconducting motors to drive the distributed fans rather than using many small conventional engines. The power to drive these electric fans is generated by two remotely located gas-turbine-driven superconducting generators. This arrangement allows many small partially embedded fans while retaining the superior efficiency of large core engines, which are physically separated but connected through electric power lines to the fans. This paper presents a brief description of the earlier CESTOL vehicle concept and the newly proposed electrically driven fan concept vehicle, using the previous CESTOL vehicle as a baseline.

Abstract: History and principles of rocket propulsion -- The thermal rocket engine -- Liquid propellant rocket engines -- Solid propellant rocket motors -- Launch vehicle dynamics -- Electric propulsion -- Nuclear propulsion -- Advanced thermal rockets.The revised edition of this practical, hands-on book discusses the range of launch vehicles in use today throughout the world, and includes the very latest details of some of the advanced propulsion systems currently being developed. The author covers the fundamentals of the subject, from the basic principles of rocket propulsion and vehicle dynamics through the theory and practice of liquid and solid propellant motors, to new and future developments. The revised edition will stick to the same principle of providing a serious exposition of the principles and practice of rocket propulsion, but from the point of view of the user and enquirer who is not an engineering specialist. Most chapters will remain substantially the same as the first edition; they will be updated where necessary and errata corrected. The main revisions will be to the chapter on electric propulsion where there have been significant new developments both in engine types and in practical applications. This is now seen as the key to planetary exploration by robotic probes and should therefore be reflected. Nuclear propulsion has emerged from the doldrums and is now seen as a definite possibility for outer solar system robotic exploration; and as enabling technology for a human mars expedition. A new chapter on nuclear thermal propulsion has been added to reflect this revival of interest.

Abstract: Reliable engine-weight estimation at the conceptual design stage is critical to the development of new aircraft engines. It helps to identify the best engine concept amongst several candidates. At NASA Glenn Research Center (GRC), the Weight Analysis of Turbine Engines (WATE) computer code, originally developed by Boeing Aircraft, has been used to estimate the engine weight of various conceptual engine designs. The code, written in FORTRAN, was originally developed for NASA in 1979. Since then, substantial improvements have been made to the code to improve the weight calculations for most of the engine components. Most recently, to improve the maintainability and extensibility of WATE, the FORTRAN code has been converted into an object-oriented version. The conversion was done within the NASA's NPSS (Numerical Propulsion System Simulation) framework. This enables WATE to interact seamlessly with the thermodynamic cycle model which provides component flow data such as airflows, temperatures, and pressures, etc., that are required for sizing the components and weight calculations. The tighter integration between the NPSS and WATE would greatly enhance system-level analysis and optimization capabilities. It also would facilitate the enhancement of the WATE code for next-generation aircraft and space propulsion systems. In this paper, the architecture of the object-oriented WATE code (or WATE++) is described. Both the FORTRAN and object-oriented versions of the code are employed to compute the dimensions and weight of a 300-passenger aircraft engine (GE90 class). Both versions of the code produce essentially identical results as should be the case.

Abstract: The research and development efforts outlined in this paper address the aerodynamic design of micro air vehicles with hovering and vertical takeoff and landing capabilities. The tilt-body configuration of the vertical takeoff and landing micro air vehicle is proposed based on a propulsion system consisting of two coaxial contrarotating motors and propellers. Values of thrust, torque, power, and efficiency of this propulsion system were measured in pusher and tractor arrangements of propellers and compared against single motor-propeller propulsion. With comparable efficiency, the developed propulsion system has very little propeller torque. Hot-wire measurements have been conducted to investigate the velocity profile in slipstream. The lower average velocity and significant decrease in velocity in the core of the slipstream found in the tractor arrangement are mostly due to the parasite drag caused by the motors. It causes the decrease of the thrust force observed for the tractor arrangement in comparison with the pusher arrangement. Wind-tunnel testing was conducted for a motor, a wing, and an arrangement of a wing with a motor. The drag force on the wing is produced by two mixing airflows: freestream and propeller-induced pulsating slipstream. The zero-lift drag coefficient increases by about 4 times with propeller-induced speed increased from 0 to 7.5 m/s. The results of this study were realized in the design of a vertical takeoff and landing micro air vehicle prototype that was successfully flight tested.

Abstract: A key technological concept for producing reliable engine diagnostics and prognostics exploits the benefits of fusing sensor data, information, and/or processing algorithms. This report describes the development of a hybrid engine model for a propulsion gas turbine engine, which is the result of fusing two diverse modeling methodologies: a physics-based model approach and an empirical model approach. The report describes the process and methods involved in deriving and implementing a hybrid model configuration for a commercial turbofan engine. Among the intended uses for such a model is to enable real-time, on-board tracking of engine module performance changes and engine parameter synthesis for fault detection and accommodation.

Abstract: The integrated propulsion motor is a drive designed for an individual self-driven container rail-platform wagon developed in the ldquointegrated standard transport unitrdquo research and development project, supported by the European commission. This paper presents the study of the motor and the converter temperatures at rated and overload working conditions. The problem is afforded by combining the simulation (finite-element method and lumped-parameter models) and the experimental approaches. For this purpose, a dedicated experimental setup has been designed and realized.

Abstract: A system is provided for optimizing a path for a marine vessel through a waterway from an initial location to a final location. The system includes a propulsion system and a directional system on the marine vessel, which impart a selective propulsion force on the marine vessel at a selective direction based on a received propulsion command and direction command from a processor. The processor determines an optimal path for the marine vessel, an optimal propulsion command and optimal directional command at a respective incremental location along the optimal path, so to optimize a performance characteristic of the marine vessel. The determination of the optimal path, the optimal propulsion command and the optimal directional command is based on the initial location, the final location, at least one operating parameter, the performance characteristic, and navigational data of the waterway.

Abstract: Having proven its utility for the simulation of single rotation propellers (SRP), the unstructured DLR TAU-Code has been applied to the unsteady simulation of isolated Contra Rotating Open Rotor (CROR) congurations. In order to demonstrate the codes applicability to the simulation of the complex aerodynamics of this type of propulsion system, a generic 8x8 pusher CROR powerplant was designed and uRANS computations at typical cruise conditions of M=0.75 and an altitude of 35,000ft were performed for the two angles of attack of 0 and 2 degrees. The results obtained allow for a detailed analysis of the complex aerodynamic interactions between the two rotors as well as an in-depth analysis of the blade and rotor forces.

Abstract: The next-generation of small satellites ('nanosats') will feature masses <10 kg and require miniaturised propulsion systems capable of providing extremely low levels of thrust The emergence of viscous, thermal and/or rarefaction effects on the micro-scale can significantly impact the flow behaviour in supersonic micronozzles resulting in performance characteristics which differ substantially from traditional macro-scale nozzle designs In this paper, we provide an overview of key findings obtained from computational studies of supersonic micronozzle flow and discuss the implications for future micro-scale nozzle design and optimisation

Abstract: Purpose – To advance the design of heat exchanged gas turbine propulsion aeroengines utilising experience gained from early development testing, and based on technologies prevailing in the 1970‐2000 time frame.Design/methodology/approach – With emphasis on recuperated helicopter turboshaft engines, particularly in the 1,000 hp (746 kW) class, detailed performance analyses, parametric trade‐off studies, and overall power plant layouts, based on state‐of‐the‐art turbomachinery component efficiencies and high‐temperature heat exchanger technologies, were undertaken for several engine configuration concepts.Findings – Using optimised cycle parameters, and the selection of a light weight tubular heat exchanger concept, an attractive engine architecture was established in which the recuperator was fully integrated with the engine structure. This resulted in a reduced overall engine weight and lower specific fuel consumption, and represented a significant advancement in technology from the modified simple‐cycle ...

Abstract: A new scramjet engine model has been developed to support hypersonic vehicle design studies and flight dynamics and control system analysis. This paper explains the methodology and the governing equations for the new propulsion system model that is suitable for use with a control oriented dynamic model of a hypersonic vehicle. Previous propulsion models used for this purpose were based on simple Rayleigh flow for the combustion process, but despite this, captured the propulsion system interactions with the vehicle aerodynamics and structural dynamics. A new, higher fidelity propulsion system model is constructed that simulates numerous phenomena that were neglected in the Rayleigh flow approach. The new model is of higher fidelity, and therefore it is not designed to calculate the flow physics on a timescale that is suitable for dynamics and control simulations. Instead it will be used as a truth model and the starting point for the derivation of a reduced-order model. Specific phenomena that are included in the new model are: a pre-combustion shock train within the isolator and its interactions with the combustor, the loss of stagnation pressure due to gas dissociation and recombination, wall heat transfer and skin friction, a fuel-air mixing submodel, and a finite-rate chemistry and autoignition reaction mechanism. It is shown that the new propulsion system model expands the operability envelope as compared to the previous model by accommodating ramjet combustion, which occurs at high supersonic/low hypersonic flight Mach numbers.

Abstract: Capsule endoscopy is a promising technique for diagnosing diseases in the small intestines. Here we propose a miniature swimming mechanism that uses MRI's magnetic fields for both propulsion and wireless energy delivery. Our method uses both the static and radio frequency (RF) magnetic field inherently available in MRI to generate propulsion force. The propulsion force is produced by a swimming tail containing waving beam consisting of three coils in a row. Alternating current in the coils acting on the static magnetic field of the MRI will generate waving movement to produce a propulsion force. RF magnetic field will provide power to generate the alternating currents in the coils. We developed a theoretical model to predict sinusoidal waves produced by the waving beam using the Euler-Bernoulli beam equation and multiple- input multiple-output system were solved using antenna design theory. This numerical model predicted that the maximal propulsion from a 10 mm long tail can produce a velocity of 7.9 mm/s force of 5.5 mN when placed in a 3T static magnetic field. A validation study with a single coil demonstrated that the theoretical and numerical model predicts well the proposed swimming mechanism and it is useful for the fabrication of swimming tails.

Abstract: With the more and more stringent energy crises and greenhouse effect, ldquomore electricrdquo transports are considered to be one of the solutions. The more electric aircraft and hybrid electric vehicle are the representation of ldquomore electricldquo transports. Some aspect of these two means of transport as installed capacity, role of electricity, electric sources, energy storage techniques and main electrical loads are compared in this paper. The future trend of ldquoelectricrdquo transport is also presented.

Abstract: In this work we address the “smoking ring” propulsion technique, originally proposed by Purcell [Am. J. Phys. 45, 3 (1977)] for self-locomotion at low Reynolds numbers. We first consider self-locomotion of a doughnut-shaped swimmer powered by surface rotation. Different modes of surface motion are assumed and propulsion velocity and swimming efficiency are determined. The swimmer is propelled against the direction of its outer surface motion, the inner surface having very little effect. The simplest swimming mode corresponding to constant angular velocity can achieve propulsion speeds of up to 66% of the surface tank-treading velocity and swimming efficiency of up to 13%. Higher efficiency is possible for more complicated modes powered by nonuniform twirling of extensible surface. A practical design of a necklace-shaped swimmer motivated by Purcell’s idea is proposed and demonstrated numerically. Finally, the explicit solution is found for the two-dimensional swimmer composed of two counter-rotating disks...

Abstract: Power electronics can enable dramatic improvements in marine platforms and ships - increased power, greater automation, with enhanced capabilities and missions. Systems with many power electronic components are emerging, driven by the need for power quality, availability, security, and efficiency. Mechanical ship propulsion systems are being replaced by electric propulsion. Variable speed motor drives are replacing across-the-line motor starters to save energy and decrease load induced instabilities. Uninterruptible power supplies are used everywhere to maintain power continuity and quality. Offshore and deep ocean platforms use many electrical motors for sea keeping and maneuvering. Marine based renewable energy concepts such as tidal and wave power generation and offshore wind farms are emerging. In all the complexity and detail of these is increasing dramatically. Todaypsilas rule-based design processes is no longer adequate. New power electronic system architectures and design concepts are the key to these advances. This paper analyzes these issues and offers solutions in the form of new ideas such as Medium Voltage DC distribution, MVDC, and a ldquorelationalrdquo design process, enabled by physics-based modeling and simulation. Paper also describes the Marine Industries Subcommittee activities in these areas and other related IEEE activities.

Abstract: A road wheel propulsion apparatus for alternately propelling and retarding the rotation of a road wheel supporting an automotive vehicle. An electric drive motor is carried by a vehicle and is drivingly connected to a road wheel to provide motive force to the vehicle by driving the road wheel in rotation relative to the vehicle. The electric drive motor includes a radially inner motor stator to be fixed to a vehicle. The electric drive motor also includes a radially outer annular motor rotor to be carried within a road wheel and to be driven in rotation relative to the motor stator by electromagnetic forces developed by between the motor stator and the motor rotor.

Abstract: A linear and a rotational switched reluctance drive with a large airgap are developed and manufactured for a test track of autonomous railway vehicles. The motor design, a coupled model and the results of finite-element-simulations are presented, along with the test bed structure and measurements. The design and control objectives are to maximize the efficiency and to minimize the acoustic noise at the given motor dimensions and the output power.

Abstract: This research effort is focused on developing a control-oriented model of a generic hypersonic vehicle that includes the interactions between several integrated components. The present paper addresses the interactions between the propulsion system and the flight dynamics of the vehicle model for two different propulsion system models. The first model is a low-fidelity propulsion model that assumes the combustion process is Rayleigh flow, and the combustor is coupled with an isentropic diffuser and internal nozzle, thus ignoring the effects of internal shock waves, area variations, and real gas effects. A second, higherfidelity propulsion system model that includes several new phenomena then analyzed. This model includes a pre-combustion shock train within the isolator and its interactions with the combustor, the loss of stagnation pressure due to gas dissociation and recombination, wall heat transfer and skin friction, a fuel-air mixing submodel, and a finite-rate chemistry description of autoignition. When the new propulsion model is added, it is observed that the poles and zeros undergo a shift, with the short-period poles moving closer to the imaginary axis. The unstable transmission zeros associated with the flight path angle are also observed to move towards the imaginary axis, and take a much more pronounced shift as compared to the short-period poles. This is attributed to a reduced lift curve slope and pitch stiffness for the high fidelity propulsion system model that stems from an change in the thrust sensitivity to angle-of-attack.