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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 541 records · Page 30
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Electromagnetic propulsion system

An electromagnetic propulsion system is provided. The system comprises first and second pluralities of stator coils wound about first and second axes, a plurality of support structures, first and second couplers that surround portions of the first and second pluralities of stator coils, and first and second pluralities of sets of rotor coils wound about axes that are parallel to the first and second axes. The stator coils are configured to receive electric current through an outside controller selecting appropriately coupled stator sections or through a sliding electrical contact system or bearing system to induce at least a first magnetic field. The plurality of support structures supports the first and second plurality of stator coils. The first and second couplers include notches and are oriented so that their notches pass over the plurality of support structures when the couplers move along the stator coils. The couplers may have an adjustable segment to close the notch. The sets of rotor coils are equidistantly attached to the couplers and are configured to receive electric current to induce magnetic fields that interact with the magnetic fields of the stator coils so that magnetic forces are applied to the plurality of rotor coils, thereby propelling the couplers along the stator coils.

Hartman, Seth↗
NASA NTRS1972

Permeameter for high-temperature magnetic measurements

A permeameter is described that measures the magnetizing force and the corresponding magnetic induction up to 1000 C. The two symmetrical yokes are made of an alloy of 9 percent iron, 91 percent cobalt. A coil surrounding the specimen supplies a magnetizing force of up to 100 oersteds. The instrument uses the magnetic potentiometer principle to cancel the effects of the reluctance of the yoke and the joint gaps. Very close agreement was obtained at room temperature when compared to an MH type permeameter. The effect of temperature on the normal induction curves for the yoke material is also presented.

Barranger, J. P.↗
NASA NTRS1994

Use of magnetic compression to support turbine engine rotors

Ever since the advent of gas turbine engines, their rotating disks have been designed with sufficient size and weight to withstand the centrifugal forces generated when the engine is operating. Unfortunately, this requirement has always been a life and performance limiting feature of gas turbine engines and, as manufacturers strive to meet operator demands for more performance without increasing weight, the need for innovative technology has become more important. This has prompted engineers to consider a fundamental and radical breakaway from the traditional design of turbine and compressor disks which have been in use since the first jet engine was flown 50 years ago. Magnetic compression aims to counteract, by direct opposition rather than restraint, the centrifugal forces generated within the engine. A magnetic coupling is created between a rotating disk and a stationary superconducting coil to create a massive inwardly-directed magnetic force. With the centrifugal forces opposed by an equal and opposite magnetic force, the large heavy disks could be dispensed with and replaced with a torque tube to hold the blades. The proof of this concept has been demonstrated and the thermal management of such a system studied in detail; this aspect, especially in the hot end of a gas turbine engine, remains a stiff but not impossible challenge. The potential payoffs in both military and commercial aviation and in the power generation industry are sufficient to warrant further serious studies for its application and optimization.

Pomfret, Chris J.↗
NASA NTRS1991

DC current monitor

A non-intrusive DC current monitor is presented which emulates the theoretical operation of an AC transformer. A conductor, carrying the current to be measured, acts as the primary of a DC current transformer. This current is passed through the center of a secondary coil, and core positioned thereabout, and produces a magnetic flux which induces a current in the secondary proportional to the current flowing in the primary. Means are provided to periodically reset the transformer core such that the measurement inaccuracies associated with core saturation are obviated. A reset current is caused to periodically flow through the secondary coil which produces a magnetic flux oppositely polarized to the flux created by the current in the primary, thus allowing ongoing measurements to be made.

Canter, Stanley↗
NASA NTRS1972

Laser beam deflection control: A concept

Improved control of laser beam deflection angles may result from new conceptual device. Reflectively coated magnetized particles are suspended in liquid-filled cell surrounded by two pairs of crossed electromagnetic coils and are selectively aligned by controlling magnetic fields. Ultrasonic energy source keeps particles suspended.

Garvie, C. L.↗
DOE OSTI2024

Understanding the impact of an applied axial magnetic field on efficient current coupling on the Z machine

Magnetized liner inertial fusion (MagLIF) is an attractive concept for producing thermonuclear fusion reactions. The MagLIF platform involves the operation of Helmholtz coils to apply a 15 Tesla axial magnetic field to the load region, where a cylindrical, fuel-filled metal liner is imploded by a ∼ 2 0 MA current pulse. The fringe field from these coils extends into the transmission line that delivers the current to the target. We investigated the extent to which this applied field disturbs the nominal power flow within that transmission line. A simplified model of the geometry shows that adding the applied magnetic field results in magnetic field lines that connect the cathode to the anode, suggesting electrons may not be magnetically insulated in this region. Particle-in-cell simulations indicated the addition of the applied magnetic field would not significantly impact the current delivery to the load. Velocimetry was used to experimentally assess the current delivery with and without the applied magnetic field. We find no measurable effects of the applied field on current delivery in the configuration investigated in this study. Published by the American Physical Society 2024

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Surrogate approximation of the Grad–Shafranov free boundary problem via stochastic collocation on sparse grids

In magnetic confinement fusion devices, the equilibrium configuration of a plasma is determined by the balance between the hydrostatic pressure in the fluid and the magnetic forces generated by an array of external coils and the plasma itself. The location of the plasma is not known a priori and must be obtained as the solution to a free boundary problem. The partial differential equation that determines the behavior of the combined magnetic field depends on a set of physical parameters (location of the coils, intensity of the electric currents going through them, magnetic permeability, etc.) that are subject to uncertainty and variability. The confinement region is in turn a function of these stochastic parameters as well. In this work, we consider variations on the current intensities running through the external coils as the dominant source of uncertainty. This leads to a parameter space of dimension equal to the number of coils in the reactor. With the aid of a surrogate function built on a sparse grid in parameter space, a Monte Carlo strategy is used to explore the effect that stochasticity in the parameters has on important features of the plasma boundary such as the location of the x-point, the strike points, and shaping attributes such as triangularity and elongation. Furthermore, the use of the surrogate function reduces the time required for the Monte Carlo simulations by factors that range between 7 and over 30.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Proton deflectometry of a capacitor coil target along two axes

A developing application of laser-driven currents is the generation of magnetic fields of picosecond–nanosecond duration with magnitudes exceeding $B=10~\text{T}$. Single-loop and helical coil targets can direct laser-driven discharge currents along wires to generate spatially uniform, quasi-static magnetic fields on the millimetre scale. Here, we present proton deflectometry across two axes of a single-loop coil ranging from 1 to 2 mm in diameter. Comparison with proton tracking simulations shows that measured magnetic fields are the result of kiloampere currents in the coil and electric charges distributed around the coil target. Using this dual-axis platform for proton deflectometry, robust measurements can be made of the evolution of magnetic fields in a capacitor coil target.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Concept Design of Active Shielding for Dynamic Wireless Charging of Light-duty EV

Dynamic wireless charging of electric vehicles is a flexible and state of the art charging technology with the potential capability of enabling fully automated in-motion charging. With charging power increasing to more than 100 kW for light duty vehicles, electromagnetic field (EMF) emission becomes a critical challenge. Due to the high costs of ferrite materials, this paper proposes an active shielding solution with multiple canceling coils installed on the ground side to supplement ferrite passive shielding to ensure electromagnetic safety. Two canceling coils are designed on two sides of the ground side coil. The canceling coils are small in size and 180 degree opposite in phase to the ground coil. Simulation and modeling shows that the canceling coils can reduce EMF emission from 37.2 µT to 18.2 µT at 0.8 m during 100 kW operation with only 2.5% of ground side current flowing in the canceling coils. These results have been preliminarily verified by inductance measurements and magnetic field measurement at 1.1 m distance without canceling coils. By further increasing the canceling coils’ currents to 4%, EMF emission can also be mitigated at 200 kW, although the canceling coils’ shape, position, and phase angle can be further optimized to improve the three-dimensional field distribution.

25 ENERGY STORAGE↗
DOE OSTI2020

Electromagnetic Shielding Design for 200 kW Stationary Wireless Charging of Light-Duty EV

Wireless power transfer (WPT) is a developing technology with the advantage of convenience and flexible charging. SAE recommended practice J2954 defines typical size and geometry with aluminum or ferrite plate shielding to limit leakage electromagnetic (EM) fields for WPT with power levels lower than 22 kVA from the input side. However, as the WPT power goes up to 100- or 200-kW level, EM safety surrounding the WPT becomes a critical concern. To address this oncoming safety challenge, a novel ferrite shielding design is proposed in this paper. Different misalignment scenarios in accordance with definitions in SAE J2954 are also taken into consideration to ensure EM safety under various operation scenarios. Simulation results, which are preliminarily verified by magnetic field measurements at 1.1 m from the center of the vehicle side coil under 100 kW operation, indicate that the magnetic field leakage can be maintained below the limits defined in SAE J2954 for 200 kW operation. A 3.3 kW scale-down test was also carried out and compared to parallel scale-down simulations. 26.8% field emission reduction is observed from the scale-down test, which supports the effectiveness of the proposed shielding design.

Zhang, Bo↗
NASA NTRS2001

Status of Pulsed Inductive Thruster Research

The TRW Pulsed Inductive Thruster (PIT) is an electromagnetic propulsion system that can provide high thrust efficiency over a wide range of specific impulse values. In its basic form, the PIT consists of a flat spiral coil covered by a thin dielectric plate. A pulsed gas injection nozzle distributes a thin layer of gas propellant across the plate surface at the same time that a pulsed high current discharge is sent through the coil. The rising current creates a time varying magnetic field, which in turn induces a strong azimuthal electric field above the coil. The electric field ionizes the gas propellant and generates an azimuthal current flow in the resulting plasma. The current in the plasma and the current in the coil flow in opposite directions, providing a mutual repulsion that rapidly blows the ionized propellant away from the plate to provide thrust. The thrust and specific impulse can be tailored by adjusting the discharge power, pulse repetition rate, and propellant mass flow, and there is minimal if any erosion due to the electrodeless nature of the discharge. Prior single-shot experiments performed with a 1-meter diameter version of the PIT at TRW demonstrated specific impulse values between 2,000 seconds and 8,000 seconds, with thruster efficiencies exceeding 55% for ammonia and hydrazine propellants. This paper outlines current and planned activities to transition the single shot device into a multiple repetition rate thruster capable of supporting future DOD and NASA strategic enterprise missions.

Hrbud, Ivana↗
NASA NTRS2002

Status of Pulsed Inductive Thruster Research

The TRW Pulsed Inductive Thruster (PIT) is an electromagnetic propulsion system that can provide high thrust efficiency over a wide range of specific impulse values. In its basic form, the PIT consists of a flat spiral coil covered by a thin dielectric plate. A pulsed gas injection nozzle distributes a thin layer of gas propellant across the plate surface at the same time that a pulsed high current discharge is sent through the coil. The rising current creates a time varying magnetic field, which in turn induces a strong azimuthal electric field above the coil. The electric field ionizes the gas propellant and generates an azimuthal current flow in the resulting plasma. The current in the plasma and the current in the coil flow in opposite directions, providing a mutual repulsion that rapidly blows the ionized propellant away from the plate to provide thrust. The thrust and specific impulse can be tailored by adjusting the discharge power, pulse repetition rate, and propellant mass flow, and there is minimal if any erosion due to the electrodeless nature of the discharge. Prior single-shot experiment,; performed with a Diameter diameter version of the PIT at TRW demonstrated specific impulse values between 2,000 seconds and 8,000 seconds, with thruster efficiencies of about 52% for ammonia. This paper outlines current and planned activities to transition the single shot device into a multiple repetition rate thruster capable of supporting NASA strategic enterprise missions.

Hrbud, Ivana↗
DOE OSTI2020

Electromagnetic Shielding Design for 200 kW Stationary Wireless Charging of Light-Duty EV

Wireless power transfer (WPT) is a developing technology with the advantage of convenience and flexible charging. SAE recommended practice J2954 defines typical size and geometry with aluminum or ferrite plate shielding to limit leakage electromagnetic (EM) fields for WPT with power levels lower than 22 kVA from the input side. However, as the WPT power goes up to 100- or 200-kW level, EM safety surrounding the WPT becomes a critical concern. To address this oncoming safety challenge, a novel ferrite shielding design is proposed in this paper. Different misalignment scenarios in accordance with definitions in SAE J2954 are also taken into consideration to ensure EM safety under various operation scenarios. Simulation results, which are preliminarily verified by magnetic field measurements at 1.1 m from the center of the vehicle side coil under 100 kW operation, indicate that the magnetic field leakage can be maintained below the limits defined in SAE J2954 for 200 kW operation. A 3.3 kW scale-down test was also carried out and compared to parallel scale-down simulations. 26.8% field emission reduction is observed from the scale-down test, which supports the effectiveness of the proposed shielding design.

25 ENERGY STORAGE↗
DOE OSTI2023

Strain measurements of Nb₃Sn coils with optical fibers

The HL-LHC at CERN will be using new superconducting quadrupole magnets (MQXFA) made of Nb₃Sn that are in the process of being tested before installation in the LHC tunnel. MQXFA07 and MQXFA08 magnets failed because of high stress developed at the coil wedge/end spacer interface, where the Nb₃Sn coil, the stainless-steel end parts, and copper wedges exhibit different strain responses. Interrogating a cut piece of coil QXFP06 with optical fibers, we expect to get a better understanding of the stress response of the coil wedge/end spacer interface.

Nisa, Kuvvetn↗
DOE OSTI2022

Gyrokinetic analysis of inter-edge localized mode transport mechanisms in a DIII-D pedestal

In this study, gyrokinetic simulations are used to study pedestal fluctuations for DIII-D discharge 174082 using the GENE code. Nonlinear local simulations indicate that electron heat flux has contributions from electron temperature gradient-driven transport but at levels insufficient to satisfy power balance. We show that microtearing modes (MTM) and neoclassical transport are likely to account for the remaining observed energy losses in the electron and ion channels, respectively. The MTM instabilities found in the simulations are consistent with the high-frequency fluctuations identified in the magnetic fluctuation data from Mirnov coils. The fluctuation data in this discharge also exhibit a low-frequency band of fluctuations. By modifying the equilibrium profiles and plasma β, simulations produce MHD modes, which may be responsible for these observed low-frequency fluctuations. We compare several metrics involving ratios of fluctuation amplitudes and transport quantities for both MTMs and MHD modes. This analysis suggests that the available data are consistent with the simultaneous activity of both MHD modes and MTMs provided that the former is limited largely to the particle transport channel.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Needed computations and computational capabilities for stellarators

Stellarator plasmas are externally controlled to a degree unparalleled by any other fusion concept, magnetic or inertial. This control is largely through the magnetic fields produced by external coils. The development of fusion energy could be expedited by carrying out remarkably straight-forward computations to define strategies for exploiting this external control. In addition to these computations, which have a reliability limited only by competence, certain physics areas that affect the development of stellarator power plants should have a more intense study. The low cost and speed with which computations can be carried out relative to experiments have implications for the development of fusion. Computations should be used to develop a strategy that to the extent possible allows major issues to be circumvented. Required computations for this strategy are the subject of this paper.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Study on ion current density of different species in laser produced plasma in a solenoid magnet

A solenoid magnetic field along the expanding laser-produced plasma is an essential technique of the laser ion source. The solenoid field can increase ion beam current at beam extraction point by a factor of 2 to over 100 by confining moving laser produced plasma in transverse direction. This technique is used everywhere from development lab to operational machine for user operation. However, the motion of ions in laser produced plasma is not fully understood. In this study, we experimentally investigated the motion of ions in a solenoid magnet (inner diameter 102 mm, coil length 1980 mm) for Al, Fe, and Ta targets. Using the following three conditions: full solenoid bore, a φ51 mm collimator on the solenoid axis, and a thin-wall φ51 mm tube at the bottom of the solenoid, we found that extracting ions at off-axis position (20~30 mm from the solenoid axis in this study) can enhance ion intensity by a factor of three or more. We continue to investigate ion motion in a solenoid field to develop better laser ion source design.

43 PARTICLE ACCELERATORS↗