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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Performance of a 12-coil superconducting bumpy torus magnet facility

The bumpy torus facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 teslas on their axes. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Final shakedown tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The facility is now ready for use as a plasma physics research facility. A maximum magnetic field on the magnetic axis of 3.23 teslas was held for a period of more than sixty minutes without a coil normalcy. The design field was 3.00 teslas. The steady-state liquid helium boil-off rate was 87 liters per hour of liquid helium without the coils charged. The coil array was stable when subjected to an impulsive loading, even with the magnets fully charged. When the coils were charged to a maximum magnetic field of 3.35 teslas, the system was driven normal without damage.

Roth, J. R.↗
NASA NTRS1972

Performance of a 12-coil superconducting 'bumpy torus' magnet facility.

The NASA-Lewis 'bumpy torus' facility consists of 12 superconducting coils, each 19 cm ID and capable of 3.0 tesla on their axes. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Final shakedown tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The facility is now ready for use as a plasma physics research facility. A maximum magnetic field on the magnetic axis of 3.23 teslas has been held for a period of more than sixty minutes without a coil normalcy.

Roth, J. R.↗
NASA NTRSDate not supplied

Risk Reduction Testing of Superconducting Coils for the High Efficiency Megawatt Motor

Second generation high temperature superconducting coils provide a very attractive level of performance for use in the field winding of electric machines for aircraft. Aside from maintaining these coils at cryogenic temperatures, much care must be taken to prevent damaging these relatively fragile materials due to excessive stress. Thermal stresses due to temperature cycling and mechanical stresses due to centrifugal forces are the most critical for the High Efficiency Megawatt Motor. This paper summarizes two test campaigns that were undertaken to reduce the risks posed by these loads. In one campaign, several superconducting coils were fabricated, thermally cycled up to 50~times, and electrically tested in liquid nitrogen to assess the change in superconductivity metrics throughout thermal cycling. In the other campaign, a full-scale superconducting coil was fabricated, a test article was designed to produce a representative stress environment in the coil, the test article and coil were rotated at room temperature up to a speed of 11,800~rpm, and the superconductivity metrics were measured in liquid nitrogen before and after each rotation. The experimental results demonstrate that the superconducting coils manufactured in house can survive both thermal cycling and high speed rotation with no appreciable degradation in superconducting performance.

partially superconducting electric machine↗
NASA NTRS1972

A 12 coil superconducting bumpy torus magnet facility for plasma research

A summary is presented of the performance of the two-coil superconducting pilot rig which preceded the NASA Lewis bumpy torus. This pilot rig was operated for 550 experimental runs over a period of 7 years. The NASA Lewis bumpy torus facility consists of 12 superconducting coils, each with a 19 cm in diameter and capable of producing magnetic field strengths of 3.0 teslas on their axes. The magnets are equally spaced around a major circumference 1.52 m in diameter, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.59 m in diameter. The design value of maximum magnetic field on the magnetic axis (3.0 teslas) was reached and exceeded. A maximum magnetic field of 3.23 teslas was held for a period of 60 minutes, and the coils did not go to normal. When the coils were charged to a maximum magnetic field of 3.35 teslas, the coil system was driven normal without damage to the facility.

Roth, J. R.↗
NASA NTRS1972

A 12-coil superconducting 'bumpy torus' magnet facility for plasma research.

A retrospective summary is presented of the performance of the two-coil superconducting pilot rig which preceded the NASA Lewis bumpy torus. The NASA Lewis bumpy torus facility consists of 12 superconducting coils, each with a 19 cm i.d. and capable of producing magnetic field strengths of 3.0 teslas on their axes. The magnets are equally spaced around a major circumference 1.52 m in diameter, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.59 m in diameter. The design value of maximum magnetic field on the magnetic axis (3.0 T) has been reached and exceeded.

Roth, J. R.↗
NASA NTRS2024

Effect of High-Speed Rotation on High-Temperature Superconducting Coils for High Efficiency Megawatt Motor

The use of a superconducting rotor in the High Efficiency Megawatt Motor (HEMM) comes with a number of challenges. The HEMM’s rotor must be designed so that the superconducting coil can tolerate the forces it will encounter during operation. These forces introduce considerable risk to the design of the HEMM. Because this risk cannot be adequately addressed through refined analysis, a set of experiments was deemed necessary to demonstrate that the HEMM’s superconducting coils can survive the stresses imparted by the centrifugal forces acting on the coil during full-speed operation of the machine. These experiments required spin testing a full-scale HEMM coil on a representative rotor structure at room temperature and sequentially higher rotation speeds and measuring the superconductivity response of the coil in liquid nitrogen (LN2) before and after each spin test. Tests were carried out to the full centripetal loading of a recent HEMM design. According to finite element analysis, this load produced stress components in the coil that exceed their design limit by a factor of 1 to 7.4. Although not yet confirmed, the current HEMM design is expected to produce even smaller stresses in the coil due to a 20 percent reduction in the coil’s mass and an increased volume of structural material. The only degradation of the coil that occurred during this testing resulted from a test rig failure and from the voltage taps, which are not part of the final coil design.

Electrified Aircraft Propulsion↗
DOE OSTI2014

Unsteady heat dissipation in accelerator superconducting coils insulated with porous ceramic insulation in normal and supercritical helium conditions

To investigate the unsteady heat dissipation in accelerator superconducting coils insulated with porous ceramic insulation, two experimental mock-ups reproducing the thermal and the mechanical conditions of a superconducting coils were produced. The mock-ups with compressive load of 10 MPa and 20 MPa were tested at normal (T = 4.23 K and p = 1 bar) and supercritical helium conditions (T = 4.23 K and p = 2.0 to 3.75 bar) during unsteady heat dissipation. The paper presents the experimental results of temperature rise in both superconducting coils as a function of time for a wide range of a localized heat load varying from 0.1 kJ/m{sup 3} up to 12.8 MJ m{sup −3} per pulse. A numerical model of the transient process in these coils has been developed and the computations are compared with the experimental results.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2019

Influence of AC Loss on Stress and Strain of Superconducting Coils

The second-generation (2G) high-temperature superconducting (HTS) coated conductors (CC) are increasingly used in power systems recently, especially in large-capacity superconducting magnetic energy storage (SMES). HTSCC in superconducting energy storage coil is subjected to thermal stress which is caused by thermal contraction due to AC loss. The thermal stress will degrade the critical currents and may cause the displacement of the superconducting coil and insulating epoxy resin. In this work, the AC loss of the superconducting coil is firstly obtained by finite element method (FEM) software COMSOL with the method of iterative conductivity. Furthermore, the effect of AC loss on the superconducting coil is thus analyzed by solving the coupling problems which include magnetic field, mechanical behaviors, and heat transfer in solids. The result shows that the AC loss of the superconducting coil is concentrated in the middle of the coil and the maximum AC loss density is 5.96 × 10{sup 5} W/m{sup 3}; the maximum stress laid at the inner radius of the coil and the maximum stress is 0.01 MPa.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Superconducting Coil Winding Machine Control System

The Spirex coil winding machine is used at Fermilab to build coils for superconducting magnets. Recently this ma-chine was equipped with a new control system, which al-lows operation from both a computer and a portable remote control unit. This control system is distributed between three layers, implemented on a PC, real-time target, and FPGA, providing respectively HMI, operational logic and direct controls. The system controls motion of all mechan-ical components and regulates the cable tension. Safety is ensured by a failsafe, redundant system.

43 PARTICLE ACCELERATORS↗
NASA NTRS1981

Application of superconducting coils to the NASA prototype magnetic balance

Application of superconducting coils to a general purpose magnetic balance was studied. The most suitable currently available superconducting cable for coils appears to be a bundle of many fine wires which are transposed and are mechanically confined. Sample coils were tested at central fields up to .5 Tesla, slewing rates up to 53 Tesla/ sec and frequencies up to 30 Hz. The ac losses were measured from helium boil-off and were approximately 20% higher than those calculated. Losses were dominated by hysteresis and a model for loss calculation which appears suitable for design purposes is presented along with computer listings. Combinations of two coils were also tested and interaction losses are reported. Two feasible geometries are also presented for prototype magnetic balance using superconductors.

Haldeman, C. W.↗
NASA NTRS1991

A deployable high temperature superconducting coil (DHTSC) - A novel concept for producing magnetic shields against both solar flare and Galactic radiation during manned interplanetary missions

The discovery of materials which are superconducting above 100 K makes possible the use of superconducting coils deployed beyong the hull of an interplanetary spacecraft to produce a magnetic shield capable of giving protection not only against solar flare radiation, but also even against Galactic radiation. Such deployed coils can be of very large size and can thus achieve the great magnetic moments required using only relatively low currents. Deployable high-temperature-superconducting coil magnetic shields appear to offer very substantial reductions in mass and energy compared to other concepts and could readily provide the radiation protection needed for a Mars mission or space colonies.

Cocks, F. Hadley↗
DOE OSTI2014

A liquid-helium-free superconducting coil system forming a flat minimum-magnetic-field distribution of an electron cyclotron resonance ion source

A flat distribution of the minimum magnetic field (flat-B{sub min}) of an electron cyclotron resonance ion source (ECRIS) is expected to perform better in highly charged ion production than classical B{sub min}. To form a flat-B{sub min} structure with a liquid helium-free superconducting device, a coil system of seven coils with four current leads has been designed. The lead number was reduced by connecting the plural coils in series to maintain the flat-B{sub min} structure even when the coil currents are changed for adjustment. This coil system can be operated with a helium-free cryostat, since the estimation of heat from the leads to the coils is nearly equivalent to the existing superconducting ECRIS of a similar type.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2016

Superconducting coil system and methods of assembling the same

A superconducting magnet apparatus is provided. The superconducting magnet apparatus includes a power source configured to generate a current; a first switch coupled in parallel to the power source; a second switch coupled in series to the power source; a coil coupled in parallel to the first switch and the second switch; and a passive quench protection device coupled to the coil and configured to by-pass the current around the coil and to decouple the coil from the power source when the coil experiences a quench.

42 ENGINEERING↗
DOE OSTI2016

Development of Magnesium Diboride Superconducting Coils for Nuclear Physics Application

The primary objective of this project is to develop an affordable magnet technology at 10-25K and then take it to a level that it can be considered mature enough to be used in a real Nuclear Physics accelerator system. We believe that because of the lower cost of magnesium diboride (MgB2) as compared to the other HTS, it offers the best such chance. Once successfully demonstrated, this exciting and innovative technology could potentially revolutionize the field the same way the conventional superconducting NbTi magnets did several decades ago. MgB2 magnets could reduce the cost of ownership (capital +operation) while enhancing performance. Another innovation is the overall cooling scheme where the exhaust gas of an existing superconducting magnet cools the inner tube which conduction cools the MgB2 coils. In several instances during the upgrade of existing facilities or designing new facilities in the Nuclear Physics or High Energy Physics communities, it is found that magnets made neither with copper coils nor with conventional superconducting NbTi coils offer an acceptable solution. Whereas copper coils limit the performance of the machine and consume large amount of power, NbTi require 4 K cryogenic facilities. This is particularly applicable in those Nuclear Physics machines where the magnetic field requirements are rather modest. One such case has been found in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) where an e-lens system is under construction to increase RHIC luminosity. In this case, magnesium diboride (MgB2) operating at 10-25 K seems to offer an exciting and practical solution. The main objective in Phase II is to demonstrate the reliability and robustness of the MgB2 coil technology, so that it is ready for use in RHIC and other user facilities. We will do this by fabricating several MgB2 coils and by conducting an exhaustive series of lifetime cycle tests. The tests will involve about a thousand ramp-up and ramp-down cycles, about 20 over current or thermal-excursions hitting the quench limit and about 10 thermal cycles. Phase II will begin with a design modeling effort of the MgB2 coils for the e-lens system with enough detail so that the magnetic, thermal and stress requirements can be understood for the fabrication and testing of representative MgB2 coils. After the technology is proven in Phase II for reliability, we will propose to use this in Phase III to upgrade RHIC e-lens system for improved luminosity performance and expect that more applications will follow in other accelerator and medical facilities.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Enhancement of the Critical Current of Bi-2223 Superconducting Coil by Using of Soft Ferromagnetic Material

The effects of soft ferromagnetic material placed nearby the high-Tc Bi-2223 coil is analyzed. Electro-magnetic simulation have been carried out to find the distributions of the magnetic field of the Bi-2223 coil. The used soft ferromagnetic material could change the distribution of the Bi-2223 coil’s magnetic field, and the transport capability of the Bi-2223 coil changes consequently. According to the simulation results, the thickness of the soft ferromagnetic material plate shows a notable effect on the coil, and the position and width of the plate could present negative effects. Experimental result of a Bi-2223 coil with B30P105 silicon steel plate is consistent with the simulation conclusions, and the critical current of the developed Bi-2223 coil could achieve an improvement of 15% by using of a piece of silicon steel plate with a thickness of 0.3 mm.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗