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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Wake characteristics of an eight-leg tower for a MOD-0 type wind turbine

Low speed wind tunnel tests were conducted to determine the flow characteristics of the wake downwind of a 1/25th scale, all tubular eight leg tower concept suitable for application to the DOE-NASA MOD-0 wind power turbine. Measurements were made of wind speed profiles, and from these were determined the wake local minimum velocity, average velocity, and width for several wind approach angles. These data are presented herein along with tower shadow photographs and comparisons with data from an earlier lattice type, four leg tower model constructed of tubular members. Values of average wake velocity defect ratio and average ratio of wake width to blade radius for the eight leg model were estimated to be around 0.17 and 0.30, respectively, at the plane of the rotor blade. These characteristics suggest that the tower wake of the eight leg concept is slightly less than that of the four leg design.

Savino, J. M.↗
NASA NTRS1978

Design and operating experience on the US Department of Energy experimental Mod-0 100-kW wind turbine

The experimental wind turbine was designed and fabricated to assess technology requirements and engineering problems of large wind turbines. The machine has demonstrated successful operation in all of its design modes and served as a prototype developmental test bed for the Mod-0A operational wind turbines which are currently used on utility networks. The mechanical and control system are described as they evolved in operational tests and some of the experience with various systems in the downwind rotor configurations are elaborated.

Glasgow, J. C.↗
NASA NTRS1977

Effects of rotor location, coning, and tilt on critical loads in large wind turbines

Three large (1500 kW) horizontal rotor configurations were analyzed to determine the effects on dynamic loads of upwind and downwind rotor locations, coned and radial blade positions, and tilted and horizontal rotor axis positions. Loads were calculated for a range of wind velocities at three locations in the structure: the blade shank, the hub shaft, and the yaw drive. Blade axis coning and rotor axis tilt were found to have little effect on loads. However, locating the rotor upwind of the tower significantly reduced loads at all locations analyzed.

Spera, D. A.↗
NASA NTRS1977

An empirical model for ocean radar backscatter and its application in inversion routine to eliminate wind speed and direction effects

Several regression models were tested to explain the wind direction dependence of the 1975 JONSWAP (Joint North Sea Wave Project) scatterometer data. The models consider the radar backscatter as a harmonic function of wind direction. The constant term accounts for the major effect of wind speed and the sinusoidal terms for the effects of direction. The fundamental accounts for the difference in upwind and downwind returns, while the second harmonic explains the upwind-crosswind difference. It is shown that a second harmonic model appears to adequately explain the angular variation. A simple inversion technique, which uses two orthogonal scattering measurements, is also described which eliminates the effect of wind speed and direction. Vertical polarization was shown to be more effective in determining both wind speed and direction than horizontal polarization.

Dome, G. J.↗
NASA NTRS1978

Scanning Electron Microscopy and Petrography of Glassy Particles Produced by Lava Fountain Eruptions

A conceptual model of a lava fountain consists of a vent, spatter ramparts, fountain column, downwind plume and associated pumice deposits. Glassy particles produced by lava fountain eruptions consist primarily of sideromelane glass and minor to moderate amounts of vesicles and crystals. Particles are classified on the basis of morphology as: (1) spherical, (2) elongate, (3) glass-coated mineral grain, (4) shard, (5) reticulite, (6) composite particle, and (7) lithic fragment.

Ladle, G. H.↗
NASA NTRS1979

Carbon fiber dispersion models used for risk analysis calculations

For evaluating the downwind, ground level exposure contours from carbon fiber dispersion, two fiber release scenarios were chosen. The first is the fire and explosion release in which all of the fibers are released instantaneously. This model applies to accident scenarios where an explosion follows a short-duration fire in the aftermath of the accident. The second is the plume release scenario in which the total mass of fibers is released into the fire plume. This model applies to aircraft accidents where only a fire results. These models are described in detail.

Source record↗
NASA NTRS1978

Design and operating experience on the U.S. Department of Energy Experimental Mod-O 100 kW Wind Turbine

The Mod-O 100 kW Experimental Wind Turbine was designed and fabricated by NASA, as part of the Federal Wind Energy Program, to assess technology requirements and engineering problems of large wind turbines. The machine became operational in October 1975 and has demonstrated successful operation in all of its design modes. During the course of its operations the machine has generated a wealth of experimental data and has served as a prototype developmental test bed for the Mod-OA operational wind turbines which are currently used on utility networks. This paper describes the mechanical and control systems as they evolved in operational tests and describes some of the experience with various systems in the downwind rotor configuration.

Glasgow, J. C.↗
NASA NTRS1978

An operating 200 kW horizontal axis wind turbine

Output from the 200-kilowatt machine will be enough to meet the power requirements of about 60 families. The experimental wind turbine generator (WTG) is a two-bladed, horizontal-axis, rotor system driving a synchronous electric generator through a step-up gear box located within a nacelle. The nacelle is mounted on top of a 100-foot tower with the rotor located downwind from the tower. The 200-kilowatt rated power output of the wind turbine is achieved at a turbine rotor speed of 40 rpm and a rated wind speed of 18.3 mph. The rated wind speed is defined as the lowest wind speed at which full power is achieved. Attention is given to operational details, aspects of blade design, blade fabrication, the use of strain gages, questions of aeroelastic stability, and an early analysis of test data.

Hunnicutt, C. L.↗
NASA NTRS1979

Fluctuations in SO2 emission during recent eruptions of Etna

The eruptive activity of July-August 1977 of Mt. Etna consisted of four separate, short eruptive episodes. The rate of SO2 emission during these eruptions was monitored using a remote-sensing correlation spectrometer. The obtained data suggest that fluctuations in the SO2 emission rate provide a means for predicting eruptions of Etna. The July-August 1977 eruptions were confined to the North East Crater vent, while continuous degassing occurred from the central vents. The continuous gas plume was blown downwind immediately after it was emitted while the eruption plumes from the North East Crater rose 500-1,000 m before being blown horizontally. Monitoring began on 24 July, immediately after the first eruptive episode had ended, and continued until 27 August.

Malinconico, L. L., Jr.↗
NASA NTRS1978

Ice nucleation activity of rocket effluent

An investigation was conducted concerning the ice nucleation activity of the exhaust products of solid rockets. The Voyager I and II payloads were launched from Kennedy Space Center on September 5 and August 20, 1977, respectively. A visible stabilized ground cloud (SGC) consisting of rocket effluent and dust formed downwind. An instrumented aircraft was used to make multiple passes in the SGC. A Mylar bag was rapidly filled with SGC aerosol and then immediately sampled with an ice nucleus counter. Analyses of rocket effluent collected are discussed, taking into account the ice nucleus concentration, particle concentration and size distribution, and the elemental composition of individual particles. A description of laboratory experiments is also presented, giving attention to the elemental composition of individual particles and the ice nucleus concentration.

Parungo, F. P.↗
NASA NTRS1979

Modification of solar lines propagating through the interplanetary medium

The optical depths of the solar H Lyman-alpha and the He 584-A lines in interplanetary space are calculated. From these the solar line profiles at Saturn and Uranus are determined. It is found that the solar H Lyman-alpha line can be diminished strongly within a spectral region of less than 0.2 A from the line center. On the other hand, there is no significant absorption of the He 584-A line except in the downwind region, where absorption occurs within a spectral region of about 0.04 A. The effects of solar line modification on planetary and interplanetary glow observations are discussed.

Wu, F. M.↗
NASA NTRS1978

Utilizing the dust streak-dryline intersection phenomenon in severe local storm forecasting

Several characteristics of a major dust storm on 20 February 1976 are presented. Four primary areas of discussion are considered: dust storm characteristics; comparisons between the cell detection capabilities of the geosynchronous satellite and radar; the use of the NASA Atmospheric and Oceanographic Information Processing System (an interactive image processing system) for interactive display of visual and IR digital data to obtain qualitative and quantitative results on specific dust cloud and cloud top characteristics; and evidence that the intersection downwind of dust clouds (streaks) with the dryline can be used to forecast the initial storm development on the dryline and that the dust clouds detected on 20 February 1976 are a reflection of upper tropospheric speed maxima, which according to McNulty (1978) and others, are associated with rapid severe convective local storm development.

Anthony, R. W.↗
NASA NTRS1978

Modulation of centimetric waves by long gravity waves - Progress report on field and laboratory results

Results are presented from laboratory and field experiments on the modulation of short waves by long waves. The field study employed a wave follower capable of tracking ocean waves with frequencies less than 1.0 Hz and heights less than 2.0 m. A high-response laser-optical system was used to detect upwind-downwind and cross-wind slopes of short waves. The laboratory study was conducted with wind over periodic long waves. The laboratory findings are discussed and compared with laboratory radar measurements and also short wave measurements obtained in the field. It is found that long waves significantly modulate the short wave dispersion by their orbital velocity, and that demodulation is necessary if the data collected by remote sensors are to be compared to surface penetrating devices. The modulation level is weak for wavelengths in the range 2.76-3.30 cm. Other relevant results are also presented.

Shemdin, O. H.↗
NASA NTRS1980

Analysis of the measured effects of the principal exhaust effluents from solid rocket motors

The feasibility of conducting environmental chamber tests using a small rocket motor to study the physical processes which occur when the exhaust products from solid motors mix with the ambient atmosphere was investigated. Of particular interest was the interaction between hydrogen chloride, aluminum oxide, and water vapor. Several types of instruments for measuring HCl concentrations were evaluated. Under some conditions it was noted that acid aerosols were formed in the ground cloud. These droplets condensed on Al2O3 nuclei and were associated with the rocket exhaust cooling during the period of plume rise to stabilization. Outdoor firings of the solid rocket motors of a 6.4 percent scaled model of the space shuttle were monitored to study the interaction of the exhaust effluents with vegetation downwind of the test site. Data concerning aluminum oxide particles produced by solid rocket motors were evaluated.

Dawbarn, R.↗
NASA NTRS1979

Results of a utility survey of the status of large wind turbine development

Wind energy conversion systems were surveyed from a utility viewpoint to establish the state of the art with regard to: (1) availability of the type of machines; (2) quality of power generation; (3) suitability for electrical grid; (4) reliability; and (5) economics. Of the 23 designs discussed, 7 have vertical axis wind turbines, 9 have upwind horizontal axis turbines, and 7 have downwind horizontal axis turbines.

Watts, A.↗
NASA NTRS1980

Assessment of Carbon Fiber Electrical Effects

The risks associated with the use of carbon fiber composites in civil aircraft are discussed along with the need for protection of civil aircraft equipment from fire-released carbon fibers. The size and number of carbon fibers released in civil aircraft crash fires, the downwind dissemination of the fibers, their penetration into buildings and equipment, and the vulnerability of electrical/electronic equipment to damage by the fibers are assessed.

Source record↗
NASA NTRS1980

Assessment of the risk due to release of carbon fiber in civil aircraft accidents, phase 2

The risk associated with the potential use of carbon fiber composite material in commercial jet aircraft is investigated. A simulation model developed to generate risk profiles for several airports is described. The risk profiles show the probability that the cost due to accidents in any year exceeds a given amount. The computer model simulates aircraft accidents with fire, release of fibers, their downwind transport and infiltration of buildings, equipment failures, and resulting ecomomic impact. The individual airport results were combined to yield the national risk profile.

Pocinki, L.↗
NASA NTRS1980

Advanced risk assessment of the effects of graphite fibers on electronic and electric equipment

An assessment of the risk associated with accidents involving aircraft with carbon fiber composite structural components is examined. The individual fiber segments cause electrical and electronic equipment to fail under certain operating conditions. A Monte Carlo simulation model was used to computer the risk. Aircraft accidents with fire, release of carbon fiber material, entrainment of carbon fibers in a smoke plume transport of fibers downwind, transfer of some fibers/into the the interior of buildings, failures of electrical and electronic equipment, and economic impact of failures are discussed. Risk profiles were prepared for individual airports and the Nation. The vulnerability of electrical transmission equipment to carbon fiber incursion and aircraft accident total costs is investigated.

Pocinki, L.↗