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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Effect of rotor configuration on guyed tower and foundation designs and estimated costs for intermediate site horizontal axis wind turbines

Three designs of a guyed cylindrical tower and its foundation for an intermediate size horizontal axis wind turbine generator are discussed. The primary difference in the three designs is the configuration of the rotor. Two configurations are two-blade rotors with teetering hubs - one with full span pitchable blades, the other with fixed pitch blades. The third configuration is a three-bladed rotor with a rigid hub and fixed pitch blades. In all configurations the diameter of the rotor is 38 meters and the axis of rotation is 30.4 meters above grade, and the power output is 200 kW and 400 kW. For each configuration the design is based upon for the most severe loading condition either operating wind or hurricane conditions. The diameter of the tower is selected to be 1.5 meters (since it was determined that this would provide sufficient space for access ladders within the tower) with guy rods attached at 10.7 meters above grade. Completing a design requires selecting the required thicknesses of the various cylindrical segments, the number and diameter of the guy rods, the number and size of soil anchors, and the size of the central foundation. The lower natural frequencies of vibration are determined for each design to ensure that operation near resonance does not occur. Finally, a cost estimate is prepared for each design. A preliminary design and cost estimate of a cantilever tower (cylindrical and not guyed) and its foundation is also presented for each of the three configurations.

Frederick, G. R.↗
NASA NTRS1982

Life and reliability models for helicopter transmissions

Computer models of life and reliability are presented for planetary gear trains with a fixed ring gear, input applied to the sun gear, and output taken from the planet arm. For this transmission the input and output shafts are co-axial and the input and output torques are assumed to be coaxial with these shafts. Thrust and side loading are neglected. The reliability model is based on the Weibull distributions of the individual reliabilities of the in transmission components. The system model is also a Weibull distribution. The load versus life model for the system is a power relationship as the models for the individual components. The load-life exponent and basic dynamic capacity are developed as functions of the components capacities. The models are used to compare three and four planet, 150 kW (200 hp), 5:1 reduction transmissions with 1500 rpm input speed to illustrate their use.

Savage, M.↗
NASA NTRS1980

The MOD-OA 200 kilowatt wind turbine generator design and analysis report

The project requirements, approach, system description, design requirements, design, analysis, system tests, installation safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the MOD-OA 200 kw wind turbine generator are discussed. The components, the rotor, driven train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electrical system, and control systems are presented. The rotor includes the blades, hub and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control and Dynamic loads and fatigue are analyzed.

Andersen, T. S.↗
NASA NTRS1982

Low-cost composite blades for the Mod-0A wind turbines

Low cost approaches to the design and fabrication of blades for a two-bladed 200 kW wind turbine were identified and the applicability of the techniques to larger and smaller blades was assessed. Blade tooling was designed and fabricated. Two complete blades and a partial blade for tool tryout were built. The patented TFT process was used to wind the entire blade. This process allows rapid winding of an axially oriented composite onto a tapered mandrel, with tapered wall thickness. The blade consists of a TFT glass-epoxy airfoil structure filament wound onto a steel root end fitting. The fitting is, in turn, bolted to a conical steel adapter section to provide for mounting attachment to the hub. Structural analysis, blade properties, and cost and weight analysis are described.

Weingart, O.↗
NASA NTRS1982

Design and evaluation of low-cost laminated wood composite blades for intermediate size wind turbines: Blade design, fabrication concept, and cost analysis

As part of a program to reduce wind turbine costs, an evaluation was conducted of a laminated wood composite blade for the Mod-OA 200 kW wind turbine. The effort included the design and fabrication concept for the blade, together with cost and load analyses. The blade structure is composed of laminated Douglas fir veneers for the primary spar and nose sections, and honeycomb cored plywood panels for the trailing edges sections. The attachment of the wood blade to the rotor hub was through load takeoff studs bonded into the blade root. Tests were conducted on specimens of the key structural components to verify the feasibility of the concept. It is concluded that the proposed wood composite blade design and fabrication concept is suitable for Mod-OA size turbines (125-ft diameter rotor) at a cost that is very competitive with other methods of manufacture.

Lieblein, S.↗
NASA NTRS1983

Examination, evaluation and repair of laminated wood blades after service on the Mod-OA wind turbine

Laminated wood blades were designed, fabricated, and installed on a 200-KW wind turbine (Mod-OA). The machine uses a two-blade rotor with a diameter of 38.1 m (125 ft). Each blade weights less than 1361 kg (3000 lb). After operating in the field, two blade sets were returned for inspection. One set had been in Hawaii for 17 months (7844 hr of operation) and the other had been at Block Island, Rhode Island, for 26 months (22 months operating - 7564 hr). The Hawaii set was returned because of one of the studs that holds the blade to the hub had failed. This was found to be caused by a combination of improper installation and inadequate corrosion protection. No other problems were found. The broken stud (along with four others that were badly corroded) was replaced and the blades are now in storage. The Block Island set of blades was returned at the completion of the test program, but one blade was found to have developed a crack in the leading edge along the entire span. This crack was found to be the result of a manufacturing process problem but was not structurally critical. When a load-deflection test was conducted on the cracked blade, the response was identical to that measured before installation. In general, the laminate quality of both blade sets was excellent. No significant internal delamination or structural defects were found in any blade. The stud bonding process requires close tolerance control and adequate corrosion protection, but studs can be removed and replaced without major problems. Moisture content stabilization does not appear to be a problem, and laminated wood blades are satisfactory for long-term operation on Mod-OA wind turbines.

Faddoul, J. R.↗
NASA NTRS1983

Corrosion fatigue of high strength fastener materials in seawater

Environmental effects which significantly reduce the fatigue life of metals are discussed. Corrosion fatigue is a major concern in the engineering application of high strength fasteners in marine environments. The corrosion fatigue failure of an AISI 41L4O high strength steel blade to hub attachment bolt at the MOD-OA 200 kW wind turbine generator was investigated. The reduction of fatigue strength of AISI 41L4O in marine environments and to obtain similar corrosion fatigue data for candidate replacement materials was studied. The AISI 4140, PH 13-8Mo stainless steel, alloy 718 and alloy MP-35N were tested in axial fatigue at a frequency of 20 Hz in dry air and natural seawater. The fatigue data are fitted by regression equations to allow determination of fatigue strength for a given number of cycles to failure.

Tipton, D. G.↗
NASA NTRS1984

Wind turbine generator interaction with conventional diesel generators on Block Island, Rhode Island. Volume 1: Executive summary

Primary results are summarized for a three-part study involving the effects of connecting a MOD-OA wind turbine generator to an isolated diesel power system. The MOD-OA installation considered was the third of four experimental nominal 200 kW wind turbines connected to various utilities under the Federal Wind Energy Program and was characterized by the highest wind energy penetration levels of four sites. The study analyses address: fuel displacement, dynamic interaction, and three modes of reactive power control. These analyses all have as their basis the results of the data acquisition program conducted on Block Island, Rhode Island.

Wilreker, V. F.↗
NASA NTRS1982

Intermediate power conditioners - Where are we now?

It has been recognized in the photovoltaic (PV) industry that even in the event of a dramatic reduction in the price of generating PV cells, the costs for the other components of the system represent still a major obstacle towards commercialization. A project was, therefore, initiated with the aim to develop baseline and conceptual power conditioner designs which would attempt to meet a specified set of cost and performance goals in the 30 to 200 kW (Intermediate) size. Resulting Intermediate Size Power Conditioner Studies led to a number of conclusions. There is a need for a set of guidelines or standards for utility interconnection. The advent of new devices with more power handling capability will change the desired topology.

Klein, J. W.↗
NASA NTRS1984

Measured effects of wind turbine generation at the Block Island Power Company

Data measurements made on the NASA MOD-OA 200-kw wind-turbine generator (WTG) installed on a utility grid form the basis for an overall performance analysis. Fuel displacement/-savings, dynamic interactions, and WTG excitation (reactive-power) control effects are studied. Continuous recording of a large number of electrical and mechanical variables on FM magnetic tape permit evaluation and correlation of phenomena over a bandwidth of at least 20 Hz. Because the wind-power penetration reached peaks of 60 percent, the impact of wind fluctuation and wind-turbine/diesel-utility interaction is evaluated in a worst-case scenario. The speed-governor dynamics of the diesel units exhibited an underdamped response, and the utility operation procedures were not altered to optimize overall WTG/utility performance. Primary findings over the data collection period are: a calculated 6.7-percent reduction in fuel consumption while generating 11 percent of the total electrical energy; acceptable system voltage and frequency fluctuations with WTG connected; and applicability of WTG excitation schemes using voltage, power, or VARS as the controlled variable.

Wilreker, V. F.↗
NASA NTRS1988

Testing of a one-bladed 30-meter-diameter rotor on the DOE/NASA Mod-O wind turbine

Tests were conducted on the DOE/NASA Mod-O 200-kW horizontal-axis wind turbine in a one-bladed rotor configuration. The objectives of the test were to evaluate the performance, loads, and dynamic characteristics of a one-bladed rotor, and then to compare these parameters with those of an aerodynamically similar two-bladed rotor configuration. Test operations showed that this intermediate-size (15.2-m radius) one-bladed rotor configuration can be operated successfully. Test results show that the one-bladed rotor had cyclic blade loads comparable to those of a two-bladed rotor. A moderate power penalty equivalent to a reduction in windspeed of 1 m/sec occurred with the one-bladed rotor when operated at a rotor speed 50 percent higher than that of the two-bladed rotor.

Ensworth, C. B. F., III↗
NASA NTRS1995

Designing A Mode Converter For Use With A Gyrotron

Report describes process of designing corrugated, circular-cross-section length of waveguide converting input electromagnetic radiation at frequency of 34.5 GHz in TM(11) mode to output radiation in HE(11) mode. TM(11)-mode input radiation supplied by gyrotron generating continuous-wave power of 200 kW at 34.5 GHz in TE(01) mode followed by TE(01)-to-TM(11) mode converter. Together, gyrotron and mode converters constitute prototype high-power transmitter for long-distance free-space communication.

Hoppe, Daniel J.↗
NASA NTRS1999

Advanced Electric Propulsion for Space Solar Power Satellites

The sun tower concept of collecting solar energy in space and beaming it down for commercial use will require very affordable in-space as well as earth-to-orbit transportation. Advanced electric propulsion using a 200 kW power and propulsion system added to the sun tower nodes can provide a factor of two reduction in the required number of launch vehicles when compared to in-space cryogenic chemical systems. In addition, the total time required to launch and deliver the complete sun tower system is of the same order of magnitude using high power electric propulsion or cryogenic chemical propulsion: around one year. Advanced electric propulsion can also be used to minimize the stationkeeping propulsion system mass for this unique space platform. 50 to 100 kW class Hall, ion, magnetoplasmadynamic, and pulsed inductive thrusters are compared. High power Hall thruster technology provides the best mix of launches saved and shortest ground to Geosynchronous Earth Orbital Environment (GEO) delivery time of all the systems, including chemical. More detailed studies comparing launch vehicle costs, transfer operations costs, and propulsion system costs and complexities must be made to down-select a technology. The concept of adding electric propulsion to the sun tower nodes was compared to a concept using re-useable electric propulsion tugs for Low Earth Orbital Environment (LEO) to GEO transfer. While the tug concept would reduce the total number of required propulsion systems, more launchers and notably longer LEO to GEO and complete sun tower ground to GEO times would be required. The tugs would also need more complex, longer life propulsion systems and the ability to dock with sun tower nodes.

Oleson, Steve↗
NASA NTRS2010

Feasibility Investigation for a Solar Power Generation Facility

The Energy Policy Act of 2005 states that by fiscal year 2013, at least 7.5% of the energy consumed by the government must be renewable energy. In an effort to help meet this goal, Johnson Space Center (JSC) is considering installing a solar power generation facility. The purpose of this project is to conduct a feasibility investigation for such a facility. Because Kennedy Space Center (KSC) has a solar power generation facility, the first step in this investigation is to learn about KSC's facility and obtain information on how it was constructed. After collecting this information, the following must be determined: the amount of power desired, the size of the facility, potential locations for it, and estimated construction and maintenance costs. Contacts with JSC's energy provider must also be established to determine if a partnership would be agreeable to both parties. Lastly, all of this data must be analyzed to decide whether or not JSC should construct the facility. The results from analyzing the data collected indicate that a 200 kW facility would provide enough energy to meet 1% of JSC's energy demand. This facility would require less than 1 acre of land. In the map below, potential locations are shown in green. The solar power facility is projected to cost $2 M. So far, the information collected indicates that such a facility could be constructed. The next steps in this investigation include contacting JSC's energy provider, CenterPoint Energy, to discuss entering a partnership; developing a life cycle cost analysis to determine payback time; developing more detailed plans; and securing funding.

Nathan, Lakshmi↗
NASA NTRS2011

Design Analysis of a High Temperature Radiator for the Variable Specific Impulse Magnetoplasma Rocket (VASIMR)

The Variable Specific Impulse Magnetoplasma Rocket (VASIMR), currently under development by Ad Astra Rocket Company, is a unique propulsion system that can potentially change the way space propulsion is performed. VASIMR's efficiency, when compared to that of a conventional chemical rocket, reduce propellant needed for exploration missions by a factor of 10. Currently plans include flight tests of a 200 kW VASIMR system, titled VF-200, on the International Space Station. The VF-200 will consist of two 100 kW thruster units packaged together in one engine bus. Each thruster unit has a unique heat rejection requirement of about 27 kW over a firing time of 15 minutes. In order to control rocket core temperatures, peak operating temperatures of about 300 C are expected within the thermal control loop. Design of a high temperature radiator is a unique challenge for the vehicle design. This paper will discuss the path taken to develop a steady state and transient based radiator design. The paper will describe radiator design options for the VASIMR thermal control system for use on ISS as well as future exploration vehicles.

Sheth, Rubik B.↗
NASA NTRS2012

Design of a High Temperature Radiator for the Variable Specific Impulse Magnetoplasma Rocket

The Variable Specific Impulse Magnetoplasma Rocket (VASIMR), currently under development by Ad Astra Rocket Company (Webster, TX), is a unique propulsion system that could change the way space propulsion is performed. VASIMR's efficiency, when compared to that of a conventional chemical rocket, reduces the propellant needed for exploration missions by a factor of 10. Currently plans include flight tests of a 200 kW VASIMR system, titled VF-200, on the International Space Station (ISS). The VF-200 will consist of two 100 kW thruster units packaged together in one engine bus. Each thruster core generates 27 kW of waste heat during its 15 minute firing time. The rocket core will be maintained between 283 and 573 K by a pumped thermal control loop. The design of a high temperature radiator is a unique challenge for the vehicle design. This paper will discuss the path taken to develop a steady state and transient-based radiator design. The paper will describe the radiator design option selected for the VASIMR thermal control system for use on ISS, and how the system relates to future exploration vehicles.

Sheth, Rubik B.↗
NASA NTRS2018

Testing with the Laser-Enhanced Arc Jet Facility (LEAF) at NASA Ames Research Center

NASA's new Laser-Enhanced Arcjet Facility (LEAF) employs 200 kilowatts of continuous-wave fiber lasers, combined with a 60-megawatt arc plasma jet, to simulate the combined radiative and convective heating is now operational and Orion heat-shield material is undergoing testing. This upgrade to the existing Interaction Heating Facility (IHF) involves the addition of high-power fiber lasers that project 1070nm radiative energy into the existing vacuum chamber. The optically expanded laser beam enters a side window of the test chamber to form either a uniform 150 x 150 mm or a 425 x 425 mm square spot on a wedge-shaped model holder. Combined heating levels of up to 180 W/cm2 convective with either 300 W/cm2 or 100 W/cm2 are achievable. This allows the arc jet and lasers to simulate dynamic entry-heating profiles encountered during entry by the Orion crew capsule for the lunar return conditions. New computational investigations are underway to explore testing with the objective of defining ablative material failure limit. Typical arc-jet testing is performed with test article that are stagnation or wedge geometries. The existing convective heating test facility combined with test article design limits how high a combined shear, heat-flux and pressure conditions can be achieved. With the addition of laser power of 200 kW, much higher combined conditions of high heat-flux, pressure and shear is achievable on a wedge or a swept-cylinder article. Such testing possibilities will allow us to progressively increase the combined conditions and explore when an ablative TPS material may fail. The presentation provides an overview of the LEAF and present results from the on-going Orion Testing.

Venkatapathy, Ethiraj↗
NASA NTRSDate not supplied

NASA Advanced Reconfigurable Electrified Aircraft Laboratory (AREAL)

The rapid maturation of electrified aircraft and the underlying technologies has outpaced the development of corresponding standards and guidelines. This is especially true with respect to the design and test of high voltage power systems and equipment. To expedite the development of these standards and guidelines, the National Aeronautics and Space Administration (NASA) Revolutionary Vertical Lift Technology (RVLT) Project has designed and built the Advanced Reconfigurable Electrified Aircraft Laboratory (AREAL). AREAL is a 200 kW High Voltage DC (HVDC) test facility that can be reconfigured to test various electrical power system (EPS) architectures and/or different types of Utilization Equipment (UE). This paper will cover AREAL and its capabilities, the testing planned within AREAL, and how the tests performed within AREAL will inform developing HVDC Power System standards, test methods and guidelines, and models.

Aerospace↗