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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Preliminary results of the large experimental wind turbine phase of the national wind energy program

The preliminary results of two projects in the development phase of reliable wind turbines designed to supply cost-competitive electrical energy were discussed. An experimental 100 kW wind turbine design and its status are first reviewed. The results of two parallel design studies for determining the configurations and power levels for wind turbines with minimum energy costs are also discussed. These studies predict wind energy costs of 1.5 to 7 cents per kW-h for wind turbines produced in quantities of 100 to 1000 per year and located at sites having average winds of 12 to 18 mph.

Thomas, R. L.↗
NASA NTRS1975

Preliminary results of the large experimental wind turbine phase of the national wind energy program

A major phase of the wind energy program is the development of reliable wind turbines for supplying cost-competitive electrical energy. This paper discusses the preliminary results of two projects in this phase of the program. First an experimental 100 kW wind turbine design and its status are reviewed. Also discussed are the results of two parallel design studies for determining the configurations and power levels for wind turbines with minimum energy costs. These studies show wind energy costs of 7 to 1.5 c/kWH for wind turbines produced in quantities of 100 to 1000 a year and located at sites having average winds of 12 to 18 mph.

Thomas, R. L.↗
NASA NTRS1975

Improved turbine disk design to increase reliability of aircraft jet engines

An analytical study was conducted on a bore entry cooled turbine disk for the first stage of the JT8D-17 high pressure turbine which had the potential to improve disk life over existing design. The disk analysis included the consideration of transient and steady state temperature, blade loading, creep, low cycle fatigue, fracture mechanics and manufacturing flaws. The improvement in life of the bore entry cooled turbine disk was determined by comparing it with the existing disk made of both conventional and advanced (Astroloy) disk materials. The improvement in crack initiation life of the Astroloy bore entry cooled disk is 87% and 67% over the existing disk made of Waspaloy and Astroloy, respectively. Improvement in crack propagation life is 124% over the Waspaloy and 465% over the Astroloy disks. The available kinetic energies of disk fragments calculated for the three disks indicate a lower fragment energy level for the bore entry cooled turbine disk.

Alver, A. S.↗
NASA NTRS1975

Trends in high temperature materials technology for advanced aircraft turbine engines

The utilization of high temperature materials for turbine blades, disks, vanes, and combustors is reviewed. The use of directionally solidified eutectic alloys and of metal fiber reinforced superalloys as turbine blade materials is discussed. The application of powder metallurgy to the production of turbine disks is considered. It is shown that oxide-dispersion strengthened alloys (including NiCr and NiCr-Al) and ceramics are the best refractory turbine vane materials. The use of heat resistant sheet alloys as combustor materials is examined. The cost benefits to be derived from the application of high temperature technology to advanced CTOL and STOL engines are described.

Blankenship, C. P.↗
NASA NTRS1976

A high pressure, high temperature combustor and turbine-cooling test facility

A new test facility is being constructed for developing turbine-cooling and combustor technology for future generation aircraft gas turbine engines. Prototype engine hardware will be investigated in this new facility at gas stream conditions up to 2480 K average turbine inlet temperature and 4.14 x 10 to the 6th power n sq m turbine inlet pressure. The facility will have the unique feature of fully automated control and data acquisition through the use of an integrated system of mini-computers and programmable controllers which will result in more effective use of operating time, will limit the number of operators required, and will provide built in self protection safety systems. The facility and the planning and design considerations are described.

Cochran, R. P.↗
NASA NTRS1976

Interim prediction method for turbine noise

A turbine noise prediction method for interim use in the NASA Aircraft Noise Prediction Program is selected. The method predicts the level, directivity, and one-third octave band spectra of far field turbine noise as a function of engine parameters. The selection results from a review of turbine noise data and prediction methods available in the open literature. It is concluded that the state-of-the-art turbine noise prediction capability is primitive and that the selected method represents only a temporary interim approach. Recommendations are made on research requirements.

Krejsa, E. A.↗
NASA NTRS1977

Attenuation of upstream-generated low frequency noise by gas turbines

The acoustic transfer functions of low frequency (below 3500 Hz) noise through aircraft turbines were investigated. Model test results were compared with theoretical predictions in order to assess the validity of the theory. Component tests were conducted on both high pressure and low pressure model turbines. The influence of inlet temperature and turbine speed attenuation was evaluated, while the effects of turbine pressure ratio, blade-row choking, and additional downstream stages were determined. Preliminary identification of pertinent aeroacoustic correlating parameters was made.

Doyle, V. L.↗
NASA NTRS1977

Analysis of regenerated single-shaft ceramic gas-turbine engines and resulting fuel economy in a compact car

Ranges in design and off-design operating conditions of an advanced gas turbine and their effects on fuel economy were analyzed. The assumed engine incorporated a single stage radial flow turbine and compressor with fixed geometry. Fuel economies were calculated over the composite driving cycle with gasoline as the fuel. At a constant turbine-inlet temperature, with a regenerator sized for a full power effectiveness the best fuel economies ranged from 11.1 to 10.2 km/liter (26.2 to 22.5 mpg) for full power turbine tip speeds of 770 to 488m/sec (2530 to 1600ft/sec), respectively.

Klann, J. L.↗
NASA NTRS1977

Dynamic blade loading in the ERDA/NASA 100 kW and 200 kW wind turbines

Dynamic blade loads, including aerodynamic, gravitational, and inertial effects, are presented for two large horizontal-axis wind turbines: the ERDA-NASA 100 kW Mod-0 and 200 kw Mod-0A wind power systems. Calculated and measured loads are compared for an experimental Mod-0 machine in operation. Predicted blade loads are also given for the higher power Mod-0A wind turbine now being assembled for operation as part of a municipal power plant. Two major structural modifications have been made to the Mod-0 wind turbine for the purpose of reducing blade loads. A stairway within the truss tower was removed to reduce the impulsive aerodynamic loading caused by the tower wake on the downwind rotor blades. Also, the torsional stiffness of the yaw drive mechanism connecting the turbine nacelle to the tower was doubled to reduce rotor-tower interaction loads. Measured reductions in load obtained by means of these two modifications equaled or exceeded predictions.

Spera, D. A.↗
NASA NTRS1976

A high-pressure, high-temperature combustor and turbine-cooling test facility

NASA-Lewis Research Center is presently constructing a new test facility for developing turbine-cooling and combustor technology for future generation aircraft gas turbine engines. Prototype engine hardware will be investigated in this new facility at gas stream conditions up to 2480 K average turbine inlet temperature and 4,140,000 N per sq m turbine inlet pressure. The facility will have the unique feature of fully-automated control and data acquisition through the use of an integrated system of minicomputers and programmable controllers, which will result in more effective use of operating time, will limit the number of operators required, and will provide a built-in self-protection safety system. The paper describes the facility and the planning and design considerations involved.

Cochran, R. P.↗
NASA NTRS1977

Synchronization of the ERDA-NASA 100 kW wind turbine generator with large utility networks

The synchronizing of a wind turbine generator against an infinite bus under random conditions is studied for the first time. With a digital computer, complete solutions for rotor speed, generator power angle, electromagnetic torque, wind turbine torque, wind turbine blade pitch angle, and armature current are obtained and presented by graphs. Experiments have been recently performed on the ERDA-NASA 100 kW wind turbine. Experimental results matched computer study results very closely and confirmed that the synchronization can be accomplished by means of the existing speed control system and an automatic synchronizer.

Hwang, H. H.↗
NASA NTRS1977

Optimization study for high speed radial turbine with special reference to design variables

Numerical results of a theoretical investigation are presented to provide information about the effect of variation of the different design and operating parameters on radial inflow turbine performance. The effects of variations in the mass flow rate, rotor tip Mach number, inlet flow angles, number of rotor blades and hub to shroud radius ratio, on the internal fluid dynamics of turbine rotors, was investigated. A procedure to estimate the flow deviation angles at the turbine exit is also presented and used to examine the influence of the operating conditions and the rotor geometrical configuration on these deviations. The significance of the results obtained is discussed with respect to improved turbine performance.

Khalil, I.↗
NASA NTRS1978

Wind Turbine Structural Dynamics

A workshop on wind turbine structural dynamics was held to review and document current United States work on the dynamic behavior of large wind turbines, primarily of the horizontal-axis type, and to identify and discuss other wind turbine configurations that may have lower cost and weight. Information was exchanged on the following topics: (1) Methods for calculating dynamic loads; (2) Aeroelasticity stability (3) Wind loads, both steady and transient; (4) Critical design conditions; (5) Drive train dynamics; and (6) Behavior of operating wind turbines.

Miller, D. R.↗
NASA NTRS1978

Automotive gas turbine fuel control

A fuel control system is reported for automotive-type gas turbines and particulary advanced gas turbines utilizing variable geometry components to improve mileage and reduce pollution emission. The fuel control system compensates for fuel density variations, inlet temperature variations, turbine vane actuation, acceleration, and turbine braking. These parameters are utilized to control various orifices, spool valves and pistons.

Gold, H.↗
NASA NTRS1978

The 200-kilowatt wind turbine project

The three 200 kilowatt wind turbines described, compose the first of three separate systems. Proposed wind turbines of the two other systems, although similar in design, are larger in both physical size and rated power generation. The overall objective of the project is to obtain early operation and performance data while gaining initial experience in the operation of large, horizontal-axis wind turbines in typical utility environments. Several of the key issues addressed include the following: (1) impact of the variable power output (due to varying wind speeds) on the utility grid (2) compatibility with utility requirements (voltage and frequency control of generated power) (3) demonstration of unattended, fail-safe operation (4) reliability of the wind turbine system (5) required maintenance and (6) initial public reaction and acceptance.

Source record↗
NASA NTRS1977

Progress in advanced high temperature turbine materials, coatings, and technology

Several NASA-sponsored benefit-cost studies have shown that very substantial benefits can be obtained by increasing material capability for aircraft gas turbines. Prealloyed powder processing holds promise for providing superalloys with increased strength for turbine disk applications. The developement of advanced powder metallurgy disk alloys must be based on a design of optimum processing and heat treating procedures. Materials considered for high temperature application include oxide dispersion strengthened (ODS) alloys, directionally solidified superalloys, ceramics, directionally solidified eutectics, materials combining the high strength of a gamma prime strengthened alloy with the elevated temperature strength of an ODS, and composites. Attention is also given to the use of high pressure turbine seals, approaches for promoting environmental protection, and turbine cooling technology.

Freche, J. C.↗
NASA NTRS1978

Synchronization of wind turbine generators against an infinite bus under gusting wind conditions

Studies of synchronizing a wind turbine generator against an infinite bus are performed on a digital computer. In the digital simulation, wind gusts of different magnitudes and durations are hypothesized. Prior to the synchronization, differences of the frequency and phase position between voltages of the alternator and the bus are also included in the simulation. Solutions for rotor speed, generator power angle, electromagnetic torque, wind turbine torque, wind turbine blade pitch angle, and armature current are simulated and presented graphically. The ERDA-NASA 100-kW wind turbine is used as a case study. The results so obtained will thus have immediate applications.

Hwang, H. H.↗
NASA NTRS1979

Utility operational experience on the NASA/DOE MOD-0A 200-kW wind turbine

The Mod-0A 200 wind turbine was designed and fabricated as part of the Federal Wind Energy Program. Early wind turbine operation and performance data were obtained while gaining initial experience in the operation of large, horizontal axis wind turbines in typical utility environments. The Mod-0A wind turbine was turned over to the Town of Clayton Light and Water Plant, Clayton, NM, for utility operation and on December 31, 1978, the machine had completed ten months of utility operation. The machine is described and the recent operational experience at Clayton, NMis documented.

Glasgow, J. C.↗