Electrical power systems.
Electric power generation systems considering chemical, solar and nuclear energy sources and types of conversion
NUCLEAR ENERGY↗
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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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Research on spacecraft and powerplant integration problems Spacecraft analysis topical report
Nuclear-electric power generating requirements for unmanned scientific solar system probes
SPACECRAFT POWER SUPPLY↗
Microelectromechanical Systems (MEMS) Broadband Light Source Developed
A miniature, low-power broadband light source has been developed for aerospace applications, including calibrating spectrometers and powering miniature optical sensors. The initial motivation for this research was based on flight tests of a Fabry-Perot fiberoptic temperature sensor system used to detect aircraft engine exhaust gas temperature. Although the feasibility of the sensor system was proven, the commercial light source optically powering the device was identified as a critical component requiring improvement. Problems with the light source included a long stabilization time (approximately 1 hr), a large amount of heat generation, and a large input electrical power (6.5 W). Thus, we developed a new light source to enable the use of broadband optical sensors in aerospace applications. Semiconductor chip-based light sources, such as lasers and light-emitting diodes, have a relatively narrow range of emission wavelengths in comparison to incandescent sources. Incandescent light sources emit broadband radiation from visible to infrared wavelengths; the intensity at each wavelength is determined by the filament temperature and the materials chosen for the filament and the lamp window. However, present commercial incandescent light sources are large in size and inefficient, requiring several watts of electrical power to obtain the desired optical power, and they emit a large percentage of the input power as heat that must be dissipated. The miniature light source, developed jointly by the NASA Glenn Research Center, the Jet Propulsion Laboratory, and the Lighting Innovations Institute, requires one-fifth the electrical input power of some commercial light sources, while providing similar output light power that is easily coupled to an optical fiber. Furthermore, it is small, rugged, and lightweight. Microfabrication technology was used to reduce the size, weight, power consumption, and potential cost-parameters critical to future aerospace applications. This chip-based light source has the potential for monolithic fabrication with on-chip drive electronics. Other uses for these light sources are in systems for vehicle navigation, remote sensing applications such as monitoring bridges for stress, calibration sources for spectrometers, light sources for space sensors, display lighting, addressable arrays, and industrial plant monitoring. Two methods for filament fabrication are being developed: wet-chemical etching and laser ablation. Both yield a 25-mm-thick tungsten spiral filament. The proof-of-concept filament shown was fabricated with the wet etch method. Then it was tested by heating it in a vacuum chamber using about 1.25 W of electrical power; it generated bright, blackbody radiation at approximately 2650 K. The filament was packaged in Glenn's clean-room facilities. This design uses three chips vacuum-sealed with glass tape. The bottom chip consists of a reflective film deposited on silicon, the middle chip contains a tungsten filament bonded to silicon, and the top layer is a transparent window. Lifetime testing on the package will begin shortly. The emitted optical power is expected to be approximately 1.0 W with the spectral peak at 1.1 mm.
Tuma, Margaret L.↗
Kinetic Model of Electric Potentials in Localized Collisionless Plasma Structures under Steady Quasi-gyrotropic Conditions
Localized plasma structures, such as thin current sheets, generally are associated with localized magnetic and electric fields. In space plasmas localized electric fields not only play an important role for particle dynamics and acceleration but may also have significant consequences on larger scales, e.g., through magnetic reconnection. Also, it has been suggested that localized electric fields generated in the magnetosphere are directly connected with quasi-steady auroral arcs. In this context, we present a two-dimensional model based on Vlasov theory that provides the electric potential for a large class of given magnetic field profiles. The model uses an expansion for small deviation from gyrotropy and besides quasineutrality it assumes that electrons and ions have the same number of particles with their generalized gyrocenter on any given magnetic field line. Specializing to one dimension, a detailed discussion concentrates on the electric potential shapes (such as "U" or "S" shapes) associated with magnetic dips, bumps, and steps. Then, it is investigated how the model responds to quasi-steady evolution of the plasma. Finally, the model proves useful in the interpretation of the electric potentials taken from two existing particle simulations.
Schindler, K.↗
Thermoacoustic Thermal Management for Electric Aircraft
Electric aircraft research and development is on the rise, necessitating an avant-garde thermal management system to effectively dissipate and reuse the typically wasted low-grade thermal energy generated on electric aircraft. Hence, the Thermal Recovery Exergy Efficient System (TREES) was successfully modeled, designed, built, and tested at NASA Glenn Research Center (NASA GRC) to demonstrate a solution. TREES demonstrates the ability to transport and amplify acoustic energy over various distances, with minimal energy dissipation, while creating a thermoacoustic heat pump that can deliver and absorb thermal energy. The in-house rig is now being utilized as a diagnostics testbed to understand the underlying physics of traveling wave thermoacoustics and to enhance future thermal management technology development.
Thermoacoustics↗
Studies of Carbon Nanotubes
The fellowship experience for this summer for 2004 pertains to carbon nanotube coatings for various space-related applications. They involve the following projects: (a) EMI protection films from HiPco-polymers, and (b) Thermal protection nanosilica materials. EMI protection films are targeted to be eventually applied onto casings of laptop computers. These coatings are composites of electrically-conductive SWNTs and compatible polymers. The substrate polymer will be polycarbonate, since computer housings are typically made of carbon composites of this type of polymer. A new experimental copolymer was used last year to generate electrically-conductive and thermal films with HiPco at 50/50 wt/wt composition. This will be one of the possible formulations. Reference films will be base polycarbonate and neat HiPco onto polycarbonate films. Other coating materials that will be tried will be based on HiPco composites with commercial enamels (polyurethane, acrylic, polyester), which could be compatible with the polycarbonate substrate. Nanosilica fibers are planned for possible use as thermal protection tiles on the shuttle orbiter. Right now, microscale silica is used. Going to the nanoscale will increase the surface-volume-per-unit-area of radiative heat dissipation. Nanoscale carbon fibers/nanotubes can be used as templates for the generation of nanosilica. A sol-gel operation is employed for this purpose.
Caneba, Gerard T.↗
Solar electric propulsion for the Halley's Comet rendezvous mission - Foundation for future missions
Long range and long duration space missions require an inexpensive and powerful means of propulsion. Solar Electric Propulsion (SEP) is considered in terms of cost effectiveness and its present state of the art. An ion propulsion system is described, which will employ solar collectors (preferably bi-flat) to generate an electric current to operate an ion thruster. The expulsion of mercury, and later, argon, ions will provide the impulse to move the spacecraft. SEP in the range of 18-60 kW, and spacecraft velocities of up to 30 km/s are discussed with reference to future exploratory missions, including: asteroid and comet rendezvous, Mars sample return, planetary orbiters, and out-of-the-ecliptic space flight. SEP applicability to earth-orbital missions is also discussed, with attention to its effectiveness in moving large objects, e.g., satellite power stations, from LEO to GEO.
Austin, R. E.↗
Electrostatic Hazard Considerations for ODC Solvent Replacement Selection Testing
ODC solvents are used to clean many critical substrates during solid rocket motor production operations. Electrostatic charge generation incidental to these cleaning operations can pose a major safety issue. Therefore, while determining the acceptability of various ODC replacement cleaners, one aspect of the selection criteria included determining the extent of electric charge generation during a typical solvent cleaning operation. A total of six candidate replacement cleaners, sixteen critical substrates, and two types of cleaning swatch materials were studied in simulated cleaning operations. Charge generation and accumulation effects were investigated by measuring the peak voltage and brush discharging effects associated with each cleaning process combination. In some cases, charge generation was found to be very severe. Using the conductivity information for each cleaner, the peak voltage data could in some cases, be qualitatively predicted. Test results indicated that severe charging effects could result in brush discharges that could potentially result in flash fire hazards when occurring in close proximity to flammable vapor/air mixtures. Process controls to effectively mitigate these hazards are discussed.
Fairbourn, Brad↗
Independent Orbiter Assessment (IOA): Analysis of the electrical power distribution and control/electrical power generation subsystem
The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C)/Electrical Power Generation (EPG) hardware. The EPD and C/EPG hardware is required for performing critical functions of cryogenic reactant storage, electrical power generation and product water distribution in the Orbiter. Specifically, the EPD and C/EPG hardware consists of the following components: Power Section Assembly (PSA); Reactant Control Subsystem (RCS); Thermal Control Subsystem (TCS); Water Removal Subsystem (WRS); and Power Reactant Storage and Distribution System (PRSDS). The IOA analysis process utilized available EPD and C/EPG hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode.
Patton, Jeff A.↗
Large velocity shears and associated electrostatic waves and turbulence in the auroral F region
Broadband electrostatic waves at 10-1000 Hz have been observed with very large shears in the plasma flow velocity transverse to the ambient magnetic field in the auroral F region. The shears were detected through their perpendicular electric field signatures, which changed by as much as 200 mV/m over distances of only a few hundred meters. Transverse shears can be uniquely related to field-aligned currents through the current continuity equation, and the resulting field-aligned drift exceeds the threshold for excitation of current-driven electrostatic ion-cyclotron waves. A numerical simulation of this instability has been used to generate electric-field spectra in the rocket frame of reference, and these spectra are similar to the spectra generated form the actual rocket data.
Earle, G. D.↗
Water Purifier
The Floatron water purifier combines two space technologies - ionization for water purification and solar electric power generation. The water purification process involves introducing ionized minerals that kill microorganisms like algae and bacteria. The 12 inch unit floats in a pool while its solar panel collects sunlight that is converted to electricity. The resulting current energizes a specially alloyed mineral electrode below the waterline, causing release of metallic ions into the water. The electrode is the only part that needs replacing, and water purified by the system falls within EPA drinking water standards.
Source record↗
Magnetogasdynamic Power Extraction and Flow Conditioning for a Gas Turbine
An extension of the Russian AJAX concept to a turbojet is being explored. This magnetohydrodynamic (MHD) energy bypass engine cycle incorporating conventional gas turbine technology has MHD flow conditioning at the inlet to electromagnetically extract part of the inlet air kinetic energy. The electrical power generated can be used for various on-board vehicle requirements including plasma flow control around the vehicle or it may be used for augmenting the expanding flow in the high speed nozzle by MHD forces to generate more thrust. In order to achieve this interaction, the air needs to be ionized by an external means even up to fairly high flight speeds, and the leading candidates may be classified as electrical discharge devices. The present kinetic modeling calculations suggest that the use of electron beams with characteristics close to the commercially available e-beam systems (electron energy approx. 60 keV, beam current approx. 0.2 mA/sq cm) to sustain ionization in intermediate pressure, low-temperature (P = 0.1 atm, T = 300 K) supersonic air flows allows considerable reduction of the flow kinetic energy (up to 10 to 20 percent in M = 3 flows). The calculations also suggest that this can be achieved at a reasonable electron beam efficiency (eta approx. 5), even if the e-beam window losses are taken into account. At these conditions, the exit NO and O atom concentrations due to e-beam initiated chemical reactions do not exceed 30 ppm. Increasing the beam current up to approx. 2 mA/sq cm, which corresponds to a maximum electrical conductivity of sigma(sub max) approx. 0.8 mho/m at the loading parameter of K = 0.5, would result in a much greater reduction of the flow kinetic energy (up to 30 to 40 percent). The MHD channel efficiency at these conditions would be greatly reduced (to eta approx. 1) due to increased electron recombination losses in the channel. At these conditions, partial energy conversion from kinetic energy to heat would result in a significant total pressure loss (P(sub 0)/P(sub 0i) approx. 0.3). The total pressure loss can be reduced operating at the loading parameter closer to unity, at the expense of the reduced electrical power output. Raising the beam current would also result in the increase of the exit O atom concentrations (up to 600 ppm) and NO (up to 150 ppm).
Adamovich, Igor V.↗
The 25 kWe solar thermal Stirling hydraulic engine system: Conceptual design
The conceptual design and analysis of a solar thermal free-piston Stirling hydraulic engine system designed to deliver 25 kWe when coupled to a 11 meter test bed concentrator is documented. A manufacturing cost assessment for 10,000 units per year was made. The design meets all program objectives including a 60,000 hr design life, dynamic balancing, fully automated control, more than 33.3 percent overall system efficiency, properly conditioned power, maximum utilization of annualized insolation, and projected production costs. The system incorporates a simple, rugged, reliable pool boiler reflux heat pipe to transfer heat from the solar receiver to the Stirling engine. The free-piston engine produces high pressure hydraulic flow which powers a commercial hydraulic motor that, in turn, drives a commercial rotary induction generator. The Stirling hydraulic engine uses hermetic bellows seals to separate helium working gas from hydraulic fluid which provides hydrodynamic lubrication to all moving parts. Maximum utilization of highly refined, field proven commercial components for electric power generation minimizes development cost and risk.
White, Maurice↗
Helical screw expander evaluation project
A one MW helical rotary screw expander power system for electric power generation from geothermal brine was evaluated. The technology explored in the testing is simple, potentially very efficient, and ideally suited to wellhead installations in moderate to high enthalpy, liquid dominated field. A functional one MW geothermal electric power plant that featured a helical screw expander was produced and then tested with a demonstrated average performance of approximately 45% machine efficiency over a wide range of test conditions in noncondensing, operation on two-phase geothermal fluids. The Project also produced a computer equipped data system, an instrumentation and control van, and a 1000 kW variable load bank, all integrated into a test array designed for operation at a variety of remote test sites. Data are presented for the Utah testing and for the noncondensing phases of the testing in Mexico. Test time logged was 437 hours during the Utah tests and 1101 hours during the Mexico tests.
Mckay, R.↗
The Endurance Rocket Mission
NASA’s Endurance sounding rocket (yard No. 47.001) will launch from Ny Ålesund, Svalbard in May 2022 on a solid fueled Oriole III-A launch vehicle. Its ∼19 minute flight will carry it to an altitude of ∼780 km above Earth’s sunlit polar cap. Its objective is to make the first measurement of the weak “ambipolar” electric field generated by Earth’s ionosphere. This field is thought to play a critical role in the upwelling and escape of ionospheric ions, and thus potentially in the evolution of Earth’s atmosphere. The results will enable us to determine the importance to ion escape of this previously unmeasured fundamental property of our planet, which will aid in a better understanding of what makes Earth habitable. Endurance will carry six science instruments (with 16 sensors) that will measure the total electrical potential drop below the spacecraft, and the physical parameters required to understand the physics of what generates the ambipolar field. The mission will be supported by simultaneous observations of solar and geomagnetic activity.
Glyn Collinson↗
Technical Challenges and Barriers Affecting Turbo-Electric and Hybrid Electric Aircraft Propulsion
In order to meet aggressive aircraft performance goals set by NASA's Aeronautics Research Mission Directorate, the Glenn Research Center (GRC) is leading research and development of electrified aircraft propulsion systems with electricity being generated from a gas turbine engine or combination of gas turbine engine and an alternate energy source. The presentation will provide an overview of technical challenges and barriers affecting the development and implementation of turboelectric and hybrid electric systems. Advances will be required in multiple areas, which include energy storage, electrical machines, power transmission, power electronics, control systems, materials, thermal management, and multi-scale modeling tools. The presentation will summarize current GRC activities in these areas. Challenges associated with integration and demonstration of multiple technologies at the system level will be presented.
Propulsion↗
Novel Thermal Energy Conversion Technologies for Advanced Electric Air Vehicles
Future air vehicles will increasingly incorporate electrical powertrains that require very tight integration of power, propulsion, thermal, and airframe technologies. This paper provides an overview of a new category of thermal energy conversion technologies that can be used to provide highly efficient turbo-generation and electric propulsion, while synergistically managing and recycling both the low grade waste heat from electrical components and the high grade waste heat from engine components.
Dyson, Rodger W.↗
Novel Thermal Energy Conversion Technologies for Advanced Electric Air Vehicles
Future air vehicles will increasingly incorporate electrical powertrains that require very tight integration of power, propulsion, thermal, and airframe technologies. This paper provides an overview of a new category of thermal energy conversion technologies that can be used to provide highly efficient turbo-generation and electric propulsion, while synergistically managing and recycling both the low grade waste heat from electrical components and the high grade waste heat from engine components.
Dyson, Rodger↗