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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Status of MSBS study at NAL

Two Magnetic Suspension and Balance Systems (MSBS) at the National Aerospace Laboratory (NAL) in Japan are introduced. They are the 10 cm MSBS and the 60 cm MSBS. They have 10 cm x 10 cm and 60 cm x 60 cm test sections. The control of suspending a model at the 10 cm MSBS is six degrees of freedom including the rolling moment control. The model for the rolling moment control has two pairs of small extra permanent magnets at both its ends plus a main cylindrical magnet. The rolling moment is generated by the magnetic forces acting on the extra magnets by controlled current passing through the four side coils independently. Test results show the roll angle of the model is controlled in this way. The dynamic calibration test was carried out at the MSBS in five degrees of freedom without the rolling moment control. The model is a simple cylindrical magnet magnetized along its axis. The obtained results show that the dynamic calibration with measured magnetic field intensity is much superior to that with the coil currents. The 60 cm MSBS was designed with some data obtained at the 10 cm one. It is fundamentally proportional to the 10 cm one in size and coil positions. The measured magnetic field intensity is not so strong as expected at design. It was operated first in 1993. The control is three degrees of freedom in the longitudinal direction.

Sawada, Hideo↗
NASA NTRS1988

A miniature, infrared pressure telemetry system

A miniature, single-channel, infrared telemetry system designed for making base pressure measurements on a wind tunnel model has been developed for the 13-inch magnetic suspension and balance system (MSBS) at Langley Research Center. The system consists of a transmitter installed in the wind tunnel model and a receiver station located outside of the test section. The onboard transmitter package includes a miniature pressure transducer, a signal conditioning circuit, and IR LED and a hearing-aid battery package. The IR LED, which is mounted flush with the model's surface, serves as the transmitter. The system is automatically activated in a magnetic field and has low power requirements. The system has been successfully employed to make low speed base pressure measurements at the 13-inch MSBS. The battery powered telemetry transmitter has a demonstrated one-hour operating life and an overall precision of better than 1/2 percent full scale.

Tcheng, Ping↗
NASA NTRS1984

Electromechanical/electromagnetics working group summary

The component and system technology issues associated with suspension and power conversion systems for the flywheel were discussed. The development of the technology consists of three major steps and encompasses a complementary mix of analytical efforts and hardware development for validation of design approaches and concept implementations. The major elements included: (1) studies to determine the optimal system configuration considering gimballed and nongimballed wheel concepts and incorporating the best 1984 component technology. These studies must also address the impact of rotor configuration on other elements of the system such as motor/generators and magnetic suspension systems to permit the selection of the optimal configuration for the demonstration phase; (2) focus the development program on integration and demonstration of a complete system which includes the rotor, suspension, and power conversion subsystems which emphasis efficiency; (3) conduct a technology program on motor/generators, suspension systems, gimbals, and sensors to take advantage of known technological advances.

Eisenhaure, D. B.↗
NASA NTRS1996

Status of MSBS Study at NAL in 1995

Magnetic field intensity and currents passing through the coils of the National Aerospace Laboratory (NAL) 1O cm Magnetic Suspension and Balance System (MSBS) were measured while a cylindrical model was oscillated along x,y,z and also about y and z axes, respectively. The model was made of alnico 5 and was 8 mm in diameter and 60 mm long. Two kinds of tests were carried out. Amplitude of the oscillation was varied at a frequency of 10 Hz. Frequency was varied from 1 to 50 Hz in the other test. Results of the tests show that the relation between coil currents and magnetic force acting on the model is affected by frequency. They also show that the relation between measured magnetic field intensity and the force in vertical direction is independent of the frequency below 30 Hz. Using the measured magnetic field intensity, the vertical force can be evaluated at the MSBS instantaneously when a model moves at frequencies below 30 Hz. A static drag force calibration test was carried out at the 60 cm MSBS. Obtained relationships between measured drag coil currents and loads shows large hysteresis.

Sawada, Hideo↗
DOE OSTI2024

Preparation and Characterization of Materials for Low- to Intermediate-Temperature CO2 Adsorption

Global carbon dioxide emissions are rising and the use of fossil fuels in several sectors are the leading causes. As global population and economies continue to grow significantly, the most practical method of lowering such emissions is to capture CO2. Although other technologies are more developed, adsorption is very promising and has attracted much attention. To ensure this technology’s success, it is essential to have suitable CO2 adsorbent materials. In this work, several new hydrotalcites (HTs) with different initial concentrations of ion precursors were prepared for the first time by the co-precipitation method—it was possible to verify that the ion concentrations influence the characteristics of the materials. The prepared HTs were characterized by thermogravimetric analysis (TG), X-Ray diffraction (XRD), surface area measurements and temperature-programmed desorption of CO2 (TPD-CO2) to relate their CO2 capture capacity to their physicochemical properties; the CO2 adsorption equilibrium isotherms were determined at 35 and 300 °C for the prepared samples, as well as for some commercial materials: magnesium oxide, calcium oxide, aluminium oxide and Zeolite 13X. After determining which materials present the best CO2 adsorption capacity, these were submitted to adsorption-desorption cycles to study their stability. The main objective of the work was to prepare and study different CO2 adsorbents for processes that are carried out at low and intermediate temperatures. From the experimental results, it was possible to conclude that the Zeolite 13X showed the best capacity at 35 °C, 3.38 mmol·g−1 (@ pCO2 = 1 bar), and a prepared calcined HT (c-HT2) was the best at 300 °C, 0.97 mmol·g−1 (@ pCO2 = 1 bar). Moreover, it seems there is an optimum initial concentration of the ions’ solutions for the tested HTs, which depends on the final application—c-HT1 showed a better capacity at 35 °C and c-HT2 at 300 °C. From the adsorption-desorption cycles—performed at 35 and 300 °C with the best materials using a magnetic suspension microbalance at 1 bar of CO2 partial pressure —, a working cyclic capacity of 2.69 mmol∙g−1 was achieved by the Zeolite at 35 °C; in turn, c-HT2 showed a working cyclic capacity of 0.79 mmol∙g−1 at 300 °C.

Figueiredo, Anabela↗
NASA NTRS1971

Hydrostatic liquid-bearing for precision gyro

Unit with 2W power increase and slightly larger overall dimensions performs as well as or better than its gas-bearing counterpart. Liquid-bearings are built by reworking serviceable gas-bearing components /sleeves, endplates, and cylinders/. Hydrostatic bearing is self-centered, requiring no magnetic suspension or centering jewel.

Sgambati, R. J.↗
NASA NTRS1973

RI 1170 advanced strapdown gyro

The major components of the RI 1170 gyroscope are described. A detailed functional description of the electronics including block diagrams and photographs of output waveshapes within the loop electronics are presented. An electronic data flow diagram is included. Those gyro subassemblies that were originally planned and subsequently changed or modified for one reason or another are discussed in detail. Variations to the original design included the capacitive pickoffs, torquer flexleads, magnetic suspension, gas bearings, electronic design, and packaging. The selection of components and changes from the original design and components selected are discussed. Device failures experienced throughout the program are reported and design corrections to eliminate the failure modes are noted. Major design deficiencies such as those of the MSE electronics are described in detail. Modifications made to the gas bearing parts and design improvements to the wheel are noted. Changes to the gas bearing prints are included as well as a mathematical analysis of the 1170 gas bearing wheel by computer analysis. The mean free-path effects on gas bearing performance is summarized.

Source record↗
NASA NTRS1975

Performance characteristics of the U.VA. superconducting wind tunnel balance

Initial operational characteristics of a wind tunnel electromagnetic balance utilizing superconducting coils are reported. Both dc and ac superconducting coils are used for balancing and measuring 3-component aerodynamic forces on simple models in Mach 3, room temperature flow. Liquid helium boil-off measurements corresponding to a wide range of operating conditions are presented together with results of systematic ac losses scaling experiments using various pancake coils wound with superconducting tape. This unique prototype facility is primarily for studying the practical feasibility of using superconducting magnetic suspension techniques for aerodynamic testing and accumulating the knowledge and expertise required for extrapolating these techniques to large-scale facilities.

Humphris, R. R.↗
NASA NTRS1976

Design features and operational characteristics of the Langley 0.3-meter transonic cryogenic tunnel

Experience with the Langley 0.3 meter transonic cryogenic tunnel, which is fan driven, indicated that such a tunnel presents no unusual design difficulties and is simple to operate. Purging, cooldown, and warmup times were acceptable and were predicted with good accuracy. Cooling with liquid nitrogen was practical over a wide range of operating conditions at power levels required for transonic testing, and good temperature distributions were obtained by using a simple liquid nitrogen injection system. To take full advantage of the unique Reynolds number capabilities of the 0.3 meter transonic tunnel, it was designed to accommodate test sections other than the original, octagonal, three dimensional test section. A 20- by 60-cm two dimensional test section was recently installed and is being calibrated. A two dimensional test section with self-streamlining walls and a test section incorporating a magnetic suspension and balance system are being considered.

Kilgore, R. A.↗
NASA NTRS1977

Studies of orbital Eoetvoes experiments

A direct force-balance technique was analyzed for carrying out the Eoetvoes experiment in space, which is intended to give sufficient sensitivity to allow investigation of the gravitational interactions of energy stored in the weak interaction. The heart of experiment is an exceedingly sensitive dual accelerometer, containing two proof masses constructed of the materials whose Eoetvoes ratio is to be compared. For use in development of the accelerometer, a magnetic microbalance is proposed in which the weight of the proof mass is supported by magnetic forces which vary very slowly with the proof mass position. It is shown that at least two different mechanizations of the magnetic suspension may be feasible.

Chapman, P. K.↗
NASA NTRS1977

Flywheel energy storage. II - Magnetically suspended superflywheel

This article, the second of a two part paper, describes the general design requirements for a flywheel energy storage system. A new superflywheel energy storage system, using a spokeless, magnetically suspended, composite material pierced disk rotor is proposed. The new system is configured around a permanent magnet ('flux biased') magnetic suspension system with active control in the radial direction and passive control in the axial direction. The storage ring is used as a moving rotor and electronic commutation of stationary armature coils is proposed. There is no mechanical contact with the rotating ring and long life and low run down losses are projected. A discussion of major components for a 10 kwh system is presented.

Kirk, J. A.↗
NASA NTRS1977

A practical magnetic bearing

A small compact magnetic bearing design developed and tested features a bearing capable of supporting over ten times its own weight, dimensioned 8 cm diam by 3.75 cm, with rare-earth cobalt magnets. Only 1% of the device payload figures as part of the magnetic suspension. The design is servoed in two axes and exhibits inherent stability in three more degrees of freedom, with full rotational freedom in the desired axis. Capacitive radial gap sensing allows stiff servoing of the rotation axis. Differential sensing and EM control linearize control functions. Low power drain, simple fabrication and assembly, and larger clearances than in air bearings or ball bearings are reported

Studer, P. A.↗
NASA NTRS1977

Optimal fine pointing control of a large space telescope using an Annular Momentum Control Device

This paper discusses the application of an Annular Momentum Control Device (AMCD) to fine pointing control of a large space telescope (LST). The AMCD represents a new development in the field of momentum storage devices. A linearized mathematical model is developed for the AMCD/LST system, including the magnetic suspension actuators. Two approaches to control system design are considered. The first approach uses a stochastic linear-quadratic Gaussian controller which utilizes feedback of all states. The second approach considers a more practical control system design in which the axial and radial loops are designed independently.

Nadkarni, A. A.↗
NASA NTRS1983

The effects of supports on the flow behind a body

Two cases in a supersonic flow with a turbulent boundary layer are studied in order to determine the effects of supports on models with a flat base. The first concerns the effect of various obstacles situated upstream of the two dimensional base, at Mach 2. The second relates to a body of revolution passing through the throat of the jet from upstream to downstream. The interference of obstacles simulating supporting masts is examined for the base, both bare and with a sting, at Mach 1.94. Without any support, the drag of a conical-cylindrical body of revolution was measured by means of the ONERA magnetic suspension. The interference of various stings was studied at Mach 2.4 with a laminary boundary layer and with a separated turbulent boundary layer. The mechanism of the interference of a sting, progressively approached axially to the base, was determined.

Rebuffet, P.↗
NASA NTRS1983

Magnetic bearing and motor

A magnetic bearing for passively suspending a rotatable element subjected to axial and radial thrust forces is disclosed. The magnetic bearing employs a taut wire stretched along the longitudinal axis of the bearing between opposed end pieces and an intermediate magnetic section. The intermediate section is segmented to provide oppositely directed magnetic flux paths between the end pieces and may include either an axially polarized magnets interposed between the segments. The end pieces, separated from the intermediate section by air gaps, control distribution of magnetic flux between the intermediate section segments. Coaxial alignment of the end pieces with the intermediate section minimizes magnetic reluctance in the flux paths endowing the bearing with self-centering characteristics when subjected to radial loads. In an alternative embodiment, pairs of oppositely wound armature coils are concentrically interposed between segments of the intermediate section in concentric arcs adjacent to radially polarized magnets to equip a magnetic bearing as a torsion drive motor. The magnetic suspension bearing disclosed provides long term reliability without maintenance with application to long term space missions such as the VISSR/VAS scanning mirror instrument in the GOES program.

Studer, P. A.↗
NASA NTRS1983

The drag of magnetically suspended wind-tunnel models with nose-cones of various shapes

This article concerns the experimental determination of optimum nose-cones (minimum drag) of a body of revolution at supersonic and hypersonic speeds by means of ONERA magnetic suspension. The study concerns two groups of models, specifically: a group whose nose-cone has a profile in the shape of X(n); the AGARD B group whose nose-cone is plotted in accordance with a given law. The results obtained for the first group are comparable to those calculated with the approximations of Cole and Newton and the experiments carried out by Kubota.

Dubois, G.↗
NASA NTRS1984

Engineering changes to the 0.1m cryogenic wind tunnel at Southampton University

The more important changes to the 0.1 m cryogenic wind tunnel since its completion in 1977 are outlined. These include detailed improvements in the fan drive to allow higher speeds, and the provision of a test section leg suitable for use with a magnetic suspension and balance system. The instrumentation, data logging, data reduction and tunnel controls were also improved and modernized. A tunnel performance summary is given.

Goodyer, M. J.↗
NASA NTRS1984

An Assessment of Integrated Flywheel System Technology

The current state of the technology in flywheel storage systems and ancillary components, the technology in light of future requirements, and technology development needs to rectify these shortfalls were identified. Technology efforts conducted in Europe and in the United States were reviewed. Results of developments in composite material rotors, magnetic suspension systems, motor/generators and electronics, and system dynamics and control were presented. The technology issues for the various disciplines and technology enhancement scenarios are discussed. A summary of the workshop, and conclusions and recommendations are presented.

Keckler, C. R.↗