Fully high temperature superconducting (HTS) machine for future electric aircraft

Because of zero resistance and diamagnetism, superconductors were more than just perfect conductors comparing to conventional conductors. Superconductors have an excellent potential for power applications use; one of the exciting areas is the superconducting machine. After hundreds of years of development, the superconducting machine’s research entered into a new era since high-temperature superconductors’ discoveries in 1986. Many pioneering works have been done by researchers worldwide. They would push the high temperature superconducting machine in commercial use for future aircraft, offshore wind generator and all-electric ship propulsion. For high power applications, superconductors can provide significantly higher current density compared to copper. The superconducting machine’s design is more efficient and has potential use in MW-class wind turbines and future electrified aircraft. Furthermore, since 1986 when HTS were discovered, much progress has been made towards making the HTS applications economically feasible due to critical temperature above 77 K. The cost of cryogenic systems significantly decreased by using liquid nitrogen. In this thesis, the work focusses on pushing the HTS machine towards commercialisation use in power applications by focussing on AC loss studies on both rotor and stator of an HTS machine. In an AC machine design, AC loss’s Joule heat needs to be accurately identified and minimised. Which can improve the stability of the machine, and also reduce the cost of the cryogenic system. On the other hand, in rotating electrical machines, AC loss is unavoidable. We must identify the AC losses in both the rotor and stator part, which are the crucial parts in future large scale machine design. To this end, in this thesis, the contribution of original new works includes: 1. Developing, validating a 10 kW fully superconducting machine prototype platform to provide a machine environment to measure AC losses of HTS windings. 2. Calorimetrically quantify the electrical HTS stator and provided data for cutting edge AC loss reduction technologies. 3. Characterisation of NI superconducting coils in the machine rotor parts design. 4. More superconducting machine design considering power electronics.Because of zero resistance and diamagnetism, superconductors were more than just perfect conductors comparing to conventional conductors. Superconductors have an excellent potential for power applications use; one of the exciting areas is the superconducting machine. After hundreds of years of development, the superconducting machine’s research entered into a new era since high-temperature superconductors’ discoveries in 1986. Many pioneering works have been done by researchers worldwide. They would push the high temperature superconducting machine in commercial use for future aircraft, offshore wind generator and all-electric ship propulsion. For high power applications, superconductors can provide significantly higher current density compared to copper. The superconducting machine’s design is more efficient and has potential use in MW-class wind turbines and future electrified aircraft. Furthermore, since 1986 when HTS were discovered, much progress has been made towards making the HTS applications economically feasible due to critical temperature above 77 K. The cost of cryogenic systems significantly decreased by using liquid nitrogen. In this thesis, the work focusses on pushing the HTS machine towards commercialisation use in power applications by focussing on AC loss studies on both rotor and stator of an HTS machine. In an AC machine design, AC loss’s Joule heat needs to be accurately identified and minimised. Which can improve the stability of the machine, and also reduce the cost of the cryogenic system. On the other hand, in rotating electrical machines, AC loss is unavoidable. We must identify the AC losses in both the rotor and stator part, which are the crucial parts in future large scale machine design. To this end, in this thesis, the contribution of original new works includes: 1. Developing, validating a 10 kW fully superconducting machine prototype platform to provide a machine environment to measure AC losses of HTS windings. 2. Calorimetrically quantify the electrical HTS stator and provided data for cutting edge AC loss reduction technologies. 3. Characterisation of NI superconducting coils in the machine rotor parts design. 4. More superconducting machine design considering power electronics

Development of a Linear Vernier Hybrid Machine for direct drive wave energy converters

PhD ThesisThe work presented in this thesis concerns the development of linear electric machines for use with wave energy converters. The machine topology selected, the Linear Vernier Hybrid Machine, is extensively investigated, specifically looking at alternative magnet configurations. Topologies are evaluated by their generation capabilities at low velocities, as demanded by Direct Drive Wave Energy Converters. Attention is mainly focused on improving the electromagnetic performance and reducing the magnet mass. A new topology of the Linear Vernier Hybrid Machine is proposed for these purposes, known later as Inset Magnet Consequent Pole machine. Tapered ferromagnetic poles are employed in this topology, which have shown a great impact on minimising the inherent pole-to-pole leakage flux as well as the unwanted cogging force. Further investigation into the Inset Magnet Consequent Pole machine focuses on improving the power factor through modifications made to the machine structure with no increase in the mass magnet, steel or copper used. Two novel variants with the added benefit of flux concentration effect are proposed and described. Finite Element Analysis is used to optimize, analyse and compare the electromagnetic performances for the three investigated machines. Considering the complexity of manufacturing and number of components, two selected topologies are built and tested in the laboratory, the Inset Magnet Consequent Pole machine and V-shape Consequent Pole machine. The experimental results are compared to the simulation results to validate the design. In general, a good agreement is shown between the predicted and measured results. Afterwards, the experimental results obtained from the two prototypes are compared with each other. These results verify that the proposed V-shape Consequent Pole topology is superior in terms of no-load back EMF, force and power factor, while it exhibits lower cogging force in comparison with the Inset Magnet Consequent Pole topology. It is therefore concluded that the V-shape Consequent Pole machine is the best compromise between power factor, efficiency and ease of manufacture. It has half the number of components per pole of the best machine design presented, yet delivers 91% of the force density and 93% of the power factor. The last part of this thesis investigates the feasibility of using the proposed V-shape Consequent Pole machine as an alternative design for an existing wave energy device developed by Uppsala University to assess the effect of employing this sort of machine on Abstract ii the overall machine size and costs. Five variants of the V-shape Consequent Pole machine are described and comparedTechnical and Vocational Training Corporation, Saudi Arabi

International Symposium on Magnetic Suspension Technology, Part 1

The goal of the symposium was to examine the state of technology of all areas of magnetic suspension and to review related recent developments in sensors and controls approaches, superconducting magnet technology, and design/implementation practices. The symposium included 17 technical sessions in which 55 papers were presented. The technical session covered the areas of bearings, sensors and controls, microgravity and vibration isolation, superconductivity, manufacturing applications, wind tunnel magnetic suspension systems, magnetically levitated trains (MAGLEV), space applications, and large gap magnetic suspension systems

The design and development of a high speed composite flywheel for hybrid vehicles

Imperial Users onl

Bibliography of Lewis Research Center technical publications announced in 1992

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1992. All the publications were announced in the 1992 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

Bibliography of Lewis Research Center technical publications announced in 1988

This bibliography contains abstracts of the technical reports that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1988. Subject, author, and corporate source indexes are also included. All the publications were announced in the 1988 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses

NASA Tech Briefs, Fall 1976

Topics include: NASA TU Services: Technology Utilization services that can assist you in learning about and applying NASA technology; New Product Ideas: A summary of seloc.ted Innovations of value to manufacturers for the development of new products; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Life Sciences; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences

Future Missions to Titan: Scientific and Engineering Challenges

Saturn’s largest moon, Titan, has been an enigma at every stage of its exploration. For three decades after the hazy atmosphere was discovered from the ground in the 1940s, debate ensued over whether it was a thin layer of methane or a dense shield of methane and nitrogen. Voyager 1 settled the matter in favor of the latter in 1980, but the details of the thick atmosphere discovered raised even more intriguing questions about the nature of the hidden surface, and the sources of resupply of methane to the atmosphere. The simplest possibility, that an ocean of methane and its major photochemical product ethane might cover the globe, was cast in doubt by Earth-based radar studies and then eliminated by Hubble Space Telescope and adaptive optics imaging in the near-infrared from large ground-based telescopes in the 1990s. These data, however, did not reveal the complexity of the surface that Cassini-Huygens would uncover beginning in 2004. A hydrological cycle appears to exist in which methane (in concert with ethane in some processes) plays the role on Titan that water plays on Earth. Channels likely carved by liquid methane and/or ethane, lakes and seas of these materials—some rivaling or exceeding North America’s Great Lakes in size—vast equatorial dune fields of complex organics made high in the atmosphere and shaped by wind, and intriguing hints of geologic activity suggest a world with a balance of geologic and atmospheric processes that is the solar system’s best analogue to Earth. Deep underneath Titan’s dense atmosphere and active, diverse surface is an interior ocean discovered by Cassini and thought to be largely composed of liquid water. Cassini-Huygens has provided spectacular data and has enabled us to glimpse the mysterious surface of Titan. However the mission will leave us with many questions that require future missions to answer. These include determining the composition of the surface and the geographic distribution of various organic constituents. Key questions remain about the ages of surface features, specifically whether cryovolcanism and tectonism are actively ongoing or are relics of a more active past. Ammonia, circumstantially suggested to be present by a variety of different kinds of Cassini-Huygens data, has yet to be seen. Is methane out-gassing from the interior or ice crust today? Are the lakes fed primarily by rain or underground methane-ethane aquifers (more properly, “alkanofers”) and how often have heavy methane rains come to the equatorial region? We should investigate whether Titan’s surface supported vaster seas of methane in the past, and whether complex self-organizing chemical systems have come and gone in the water volcanism, or even exist in exotic form today in the high latitude lakes. The presence of a magnetic field has yet to be established. A large altitude range in the atmosphere, from 400–900 km in altitude, will remain poorly explored after Cassini. Much remains to be understood about seasonal changes of the atmosphere at all levels, and the long-term escape of constituents to space. Other than Earth, Titan is the only world in our solar system known to have standing liquids and an active “hydrologic cycle” with clouds, rains, lakes and streams. The dense atmosphere and liquid lakes on Titan’s surface can be explored with airborne platforms and landed probes, but the key aspect ensuring the success of future investigations is the conceptualization and design of instruments that are small enough to fit on the landed probes and airborne platforms, yet sophisticated enough to conduct the kinds of detailed chemical (including isotopic), physical, and structural analyses needed to investigate the history and cycling of the organic materials. In addition, they must be capable of operating at cryogenic temperatures while maintaining the integrity of the sample throughout the analytic process. Illuminating accurate chemistries also requires that the instruments and tools are not simultaneously biasing the measurements due to localized temperature increases. While the requirements for these techniques are well understood, their implementation in an extremely low temperature environment with limited mass, power and volume is acutely challenging. No such instrument systems exist today. Missions to Titan are severely limited in both mass and power because spacecraft have to travel over a billion miles to get there and require a large amount of fuel, not only to reach Titan, but to maintain the ability to maneuver when they arrive. Landed missions have additional limitations, in that they must be packaged in a sealed aeroshell for entry into Titan’s atmosphere. Increases in landed mass and volume translate to increased aeroshell mass and size, requiring even more fuel for delivery to Titan. Nevertheless, missions during which such systems and instruments could be employed range from Discovery and New Frontiers class in situ probes that might be launched in the next decade, to a full-up Flagship class mission anticipated to follow the Europa Jupiter System Mission. Capitalizing on recent breakthroughs in cryo-technologies and smart materials fabrication, we developed conceptual designs of sample acquisition systems and instruments capable of in situ operation under low temperature environments. The study included two workshops aimed at brainstorming and actively discussing a broad range of ideas and associated challenges with landing instruments on Titan, as well as more focused discussions during the intervening part of the study period. The workshops each lasted ~4 days (Monday-Thursday/Friday), included postdoctoral fellows and students in addition to the core team members, and generated active engagement from the Caltech and JPL team participants, as well as from the outside institutions. During the workshops, new instruments and sampling methodologies were identified to handle the challenges of characterizing everything from small molecules in Titan’s upper atmosphere to gross mixtures of high molecular weight complex organics in condensed phases, including atmospheric aerosols and “organic sand” in dunes, to highly dilute components in ices and lakes. To enable these advances in cryogenic instrumentation breakthroughs in a wide range of disciplines, including electronics, chemical and mechanical engineering, and materials science were identified

Bibliography of Lewis Research Center Technical Publications announced in 1991

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific engineering work performed and managed by the Lewis Research Center in 1991. All the publications were announced in the 1991 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses