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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

RL-34 ring laser gyro laboratory evaluation for the Deep Space Network antenna application

The overall results of this laboratory evaluation are quite encouraging. The gyro data is in good agreement with the system's overall pointing performance, which is quite close to the technical objectives for the Deep Space Network (DSN) application. The system can be calibrated to the levels required for millidegree levels of pointing performance, and initialization performance is within the required 0.001 degree objective. The blind target acquisition performance is within a factor of two of the 0.0001 degree objective, limited only by a combination of the slow rate (0.5 deg/sec) and the existing production quantization logic (0.38 arc-sec/pulse). Logic circuitry exists to better this performance such that it will better the objective by 50 percent. Representative data with this circuitry has been provided for illustration. Target tracking performance is about twice the one millidegree objective, with several factors contributing. The first factor is the bias stability of the gyros, which is exceptional, but will limit performance to the 0.001 and 0.002 degree range for long tracking periods. The second contributing factor is the accelerometer contributions when the system is elevated. These degrade performance into the 0.003 to 0.004 degree range, which could be improved upon with some additional changes. Finally, we have provided a set of recommendations to improve performance closer to the technical objectives. These recommendations include gyro, electronics, and system configurational changes that form the basis for additional work to achieve the desired performance. In conclusion, we believe that the RL-34 ring laser gyro-based advanced navigation system demonstrated performance consistent with expectations and technical objectives, and it has the potential for even further enhancement for the DSN application.

Source record↗
NASA NTRS1995

Scramjet Performance Assessment Using Water Absorption Diagnostics (U)

Simultaneous multiple path measurements of temperature and H2O concentration will be presented for the AIMHYE test entries in the NASA Ames 16-Inch Shock Tunnel. Monitoring the progress of high temperature chemical reactions that define scramjet combustor efficiencies is a task uniquely suited to nonintrusive optical diagnostics. One application strategy to overcome the many challenges and limitations of nonintrusive measurements is to use laser absorption spectroscopy coupled with optical fibers. Absorption spectroscopic techniques with rapidly tunable lasers are capable of making simultaneous measurements of mole fraction, temperature, pressure, and velocity. The scramjet water absorption diagnostic was used to measure combustor efficiency and was compared to thrust measurements using a nozzle force balance and integrated nozzle pressures to develop a direct technique for evaluating integrated scramjet performance. Tests were initially performed with a diode laser tuning over a water absorption feature at 1391.7 nm. A second diode laser later became available at a wavelength near 1343.3 nm covering an additional water absorption feature and was incorporated in the system for a two-wavelength technique. Both temperature and mole fraction can be inferred from the lineshape analysis using this approach. Additional high temperature spectroscopy research was conducted to reduce uncertainties in the scramjet application. The lasers are optical fiber coupled to ports at the combustor exit and in the nozzle region. The output from the two diode lasers were combined in a single fiber, and the resultant two-wavelength beam was subsequently split into four legs. Each leg was directed through 60 meters of optical fiber to four combustor exit locations for measurement of beam intensity after absorption by the water within the flow. Absorption results will be compared to 1D combustor analysis using RJPA and nozzle CFD computations as well as to data from a nozzle metric balance measuring thrust and integrated pressure measurements along the length of the nozzle. Assessment of its value as a combustor performance evaluation tool will be conducted.

Cavolowsky, John A.↗
NASA NTRS1980

MOD-0A 200 kW wind turbine generator design and analysis report

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. 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 wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl 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 are discussed. Systems analyses on dynamic loads and fatigue are presented.

Anderson, T. S.↗
NASA NTRS1974

Highly loaded multi-stage fan drive turbine - performance of initial seven configurations

Experimental results of a three-stage highly loaded fan drive turbine test program are presented. A plain blade turbine, a tandem blade turbine, and a tangentially leaned stator turbine were designed for the same velocity diagram and flowpath. Seven combinations of bladerows were tested to evaluate stage performances and effects of the tandem blading and leaned stator. The plain blade turbine design point total-to-total efficiency was 0.886. The turbine with the stage three leaned stator had the same efficiency with an improved exit swirl profile and increased hub reaction. Two-stage group tests showed that the two-stage turbine with tandem stage two stator had an efficiency of 0.880 compared to 0.868 for the plain blade two-stage turbine.

Wolfmeyer, G. W.↗
NASA NTRS1980

Radio frequency performance of DSS 14 64-meter antenna at X-band using an improved subreflector

The performance of the Deep Space Station (DSS) 14 64-meter antenna X-band gain determined using the X- and K-band Radar feedcone is discussed. Tests prior to, and following the installation of an improved subreflector, proved the unit largely (if not totally) restored initial performance levels at that station. The X-band peak gain with the subreflector is +17.8dBi(area efficiency of 47.3 percent); an increase of +0.47 dB due to the unit installation. The test further showed a significant shift in the axial focus required (function of elevation angle) which, if not implemented operationally, will cause a serious degradation. An historical summary of all documented X-band gain measurements at DSS 14 is included and reviewed. The initial performance is traced through various major configuration changes such as the installation of the X-band dual hybrid mode horn within the operational XRO feedcone. Finally, based on the summary and recent data, a peak X-band antenna gain of +72.1 dBi (area efficiency of 50.8 percent) is projected for the operational feedcone.

Freiley, A. J.↗
NASA NTRS2015

SARDA HITL #6 Simulation: System Performance Analysis (Initial Results)

This presentation discusses the results of the 6th human-in-the-loop simulation of the Spot and Runway Departure Advisor (SARDA). SARDA is a research prototype decision support tool for both Air Traffic Control Tower controllers and airlines ramp controllers to assit in controlling surface traffic of a busy airport. Data was collected during the human-in-the-loop simulations of SARDA for ramp operatoins at Charlotte International Airport (Oct-Nov 2014). The performance results include taxi time, taxi delay, total delay, and runway usage.

surface management↗
NASA NTRS1975

Description and initial operating performance of the Langley 6-inch expansion tube using heated helium driver gas

A general description of the Langley 6-inch expansion tube is presented along with discussion of the basic components, internal resistance heater, arc-discharge assemblies, instrumentation, and operating procedure. Preliminary results using unheated and resistance-heated helium as the driver gas are presented. The driver-gas pressure ranged from approximately 17 to 59 MPa and its temperature ranged from 300 to 510 K. Interface velocities of approximately 3.8 to 6.7 km/sec were generated between the test gas and the acceleration gas using air as the test gas and helium as the acceleration gas. Test flow quality and comparison of measured and predicted expansion-tube flow quantities are discussed.

Moore, J. A.↗
NASA NTRS1978

In-flight performance of the IUE

A report on the initial performance of the IUE satellite, launched in January, 1978, is given. Attention is given to optical performance, camera performance, background corrections, photometric performance, and data reduction. Samples of high-dispersion and low-dispersion spectra are shown. A remaining problem of proper separation of high dispersion orders in data reduction is discussed.

Boggess, A.↗
NASA NTRS1989

Investigation of heat transfer in zirconium potassium perchlorate at low temperature: A study of the failure mechanism of the NASA standard initiator

The objective of this work was to study the reasons for the failure of pyrotechnic initiators at very low temperatures (10 to 100 K). A two-dimensional model of the NASA standard initiator was constructed to model heat transfer from the electrically heated stainless steel bridgewire to the zirconium potassium perchlorate explosive charge and the alumina charge cup. Temperature dependent properties were used in the model to simulate initiator performance over a wide range of initial temperatures (10 to 500 K). A search of the thermophysical property data base showed that pure alumina has a very high thermal conductivity at low temperatures. It had been assumed to act as a thermal insulator in all previous analyses. Rapid heat transfer from the bridgewire to the alumina at low initial temperatures was shown to cause failure of the initiators if the wire did not also make good contact with the zirconium potassium perchlorate charge. The mode is able to reproduce the results of the tests that had been conducted to investigate the cause for failure. It also provides an explanation for previously puzzling results and suggests simple design changes that will increase reliability at very low initial temperatures.

Varghese, Philip L.↗
NASA NTRSDate not supplied

Convertor Development for Dynamic Radioisotope Power Systems

Dynamic power conversion technologies are being developed for future space science and exploration missions by NASA’s Radioisotope Power Systems (RPS) Program, in collaboration with the U.S. Department of Energy (DOE). The Dynamic Radioisotope Power Systems (DRPS) Project is working to mature dynamic power convertors and controllers for infusion into a potential future flight generators.1,2 Maturation of power conversion technologies is being executed by the DRPS Project and the Thermal Energy Conversion Branch, located at NASA’s Glenn Research Center (GRC), and includes convertor technology development contracts and in-house controller development. The convertor technology development contracts consist of three contractors tasked to design, fabricate, and complete performance testing before the units are delivered to GRC for independent assessment. All contractors have completed convertor designs and are fabricating convertors to enable performance testing, while one has demonstrated initial performance of their design. The contractors also have provided generator conceptual designs, which utilize their respective convertor technologies being developed.

Dynamic↗
NASA NTRS1988

Performance of lightweight nickel electrodes

The NASA Lewis Research Center is currently developing nickel electrodes for nickel-hydrogen (Ni-H2) batteries. These electrodes are lighter in weight and have higher energy densities than the heavier state-of-the-art (SOA) sintered nickel electrodes. In the present approach, lightweight materials or plaques are used as conductive supports for the nickel hydroxide active material. These plaques (fiber and felt, nickel plated plastic and graphite) are commercial products that are fabricated into nickel electrodes by electrochemically impregnating them with active material. Evaluation is performed in half cells structured in the bipolar configuration. Initial performance tests include capacity measurements at five discharge levels, C/2, 1.0C 1.37C, 2.0C and 2.74C. The electrodes that pass the initial tests are life cycle tested in a low Earth orbit regime at 80 percent depth of discharge. Different formulations of nickel fiber materials obtained from several manufacturers are currently being tested as possible candidates for nickel electrodes. One particular lightweight fiber mat electrode has accumulated over 3000 cycles to date, with stable capacity and voltage. Life and performance data of this electrode were investigated and presented. Good dimensional stability and active material adherence have been demonstrated in electrodes made from this lightweight plaque.

Britton, Doris L.↗
NASA NTRS1988

Performance of lightweight nickel electrodes

The NASA Lewis Research Center is currently developing nickel electrodes for nickel-hydrogen (Ni-H2) batteries. These electrodes are lighter in weight and have higher energy densities than the heavier state-of-the-art (SOA) sintered nickel electrodes. In the present approach, lightweight materials or plaques are used as conductive supports for the nickel hydroxide active material. These plaques (fiber and felt, nickel plated plastic and graphite) are commercial products that are fabricated into nickel electrodes by electrochemically impregnating them with active material. Evaluation is performed in half cells structured in the bipolar configuration. Initial performance tests include capacity measurements at five discharge levels, C/2, 1.0C, 1.37C, 2.0C and 2.74C. The electrodes that pass the initial tests are life cycle tested in a low earth orbit regime at 80 percent depth of discharge. Different formulations of nickel fiber materials obtained from several manufacturers are currently being tested as possible candidates for nickel electrodes. One particular lightweight fiber mat electrode has accumulated over 3000 cycles to date, with stable capacity and voltage. Life and performance data of this electrode were investigated and presented. Good dimensional stability and active material adherence have been demonstrated in electrodes made from this lightweight plaque.

Britton, Doris L.↗
NASA NTRS1981

Endurance test and evaluation of alkaline water electrolysis cells

Utilization in the development of multi-kW low orbit power systems is discussed. The following technological developments of alkaline water electrolysis cells for space power application were demonstrated: (1) four 92.9 cm2 single water electrolysis cells, two using LST's advanced anodes and two using LST's super anodes; (2) four single cell endurance test stands for life testing of alkaline water electrolyte cells; (3) the solid performance of the advanced electrode and 355 K; (4) the breakthrough performance of the super electrode; (5) the four single cells for over 5,000 hours each significant cell deterioration or cell failure. It is concluded that the static feed water electrolysis concept is reliable and due to the inherent simplicity of the passive water feed mechanism coupled with the use of alkaline electrolyte has greater potential for regenerative fuel cell system applications than alternative electrolyzers. A rise in cell voltage occur after 2,000-3,000 hours which was attributed to deflection of the polysulfone end plates due to creepage of the thermoplastic. More end plate support was added, and the performance of the cells was restored to the initial performance level.

Burke, K. A.↗
NASA NTRS2014

Performance Testing of the Astro-H Flight Model 3-Stage ADR

The Soft X-ray Spectrometer (SXS) is one of four instruments that will be flown on the Japanese Astro-H satellite, planned for launch in late 2015early 2016. The SXS will perform imaging spectroscopy in the soft x-ray band using a 6x6 array of silicon micro calorimeters operated at 50 mK, cooled by an adiabatic demagnetization refrigerator (ADR). NASAGSFC is providing the detector array and ADR, and Sumitomo Heavy Industries, Inc. is providing the remainder of the cryogenic system (superfluid helium dewar (1.3 K), Stirling cryocoolers and a 4.5 K Joule-Thomson (JT) cryocooler). The ADR is unique in that it is designed to use both the liquid helium and the JT cryocooler as it heat sink. The flight detector and ADR assembly have successfully undergone vibration and performance testing at GSFC, and have now undergone initial performance testing with the flight dewar at Sumitomo Heavy Industries, Inc. in Japan. This presentation summarizes the performance of the flight ADR in both cryogen-based and cryogen-free operating modes.

adiabatic demagnetization refrigerator↗
NASA NTRS1989

Lightweight fibrous nickel electrodes for nickel-hydrogen batteries

The NASA Lewis Research Center is currently developing nickel electrodes for nickel-hydrogen batteries. These electrodes are lighter in weight and have higher energy densities than the heavier state-of-the-art sintered nickel electrodes. Lightweight fibrous materials or plaques are used as conductive supports for the nickel hydroxide active material. These materials are commercial products that are fabricated into nickel electrodes by electrochemically impregnating them with active material. Evaluation is performed in half cells structured in the bipolar configuration. Initial performance tests include capacity measurements at five discharge levels, C/2, 1.0C, 1.37C, 2.0C, and 2.74C. The electrodes that pass the initial tests are life cycle-tested in a low Earth orbit regime at 80 percent depth of discharge.

Britton, Doris L.↗
NASA NTRS1991

Evaluation of GPS/UTC steering performance

The Global Positioning System (GPS) is required to maintain GPS time to Universal Coordinated Time (UTC) to an accuracy of one microsecond and broadcast to the user the offset between GPS and UTC to an accuracy of 100 nanoseconds (1 sigma). On 25 Jun. 1990, an automatic steering algorithm was implemented to control GPS time to synchronize it with UTC. The description of the steering laws and predicted performance results were presented at the 1989 Precise Time and Time Interval (PTTI) conference, while preliminary performance results were presented at the 1990 PTTI conference. The initial performance was not as predicted, resulting in an in-depth analysis of the observed performance and a more thorough sensitivity analysis. In addition, responses to anomalies were investigated. This paper will describe these analyses and results, and evaluate actual steering performance from Jun. 1990 to Nov. 1991. Although anomalies were observed during the initial phase of steering, recent experience is more in line with expectations.

W. A. Feess↗
NASA NTRS1983

Numerical Aerodynamic Simulation (NAS)

The history of the Numerical Aerodynamic Simulation Program, which is designed to provide a leading-edge capability to computational aerodynamicists, is traced back to its origin in 1975. Factors motivating its development and examples of solutions to successively refined forms of the governing equations are presented. The NAS Processing System Network and each of its eight subsystems are described in terms of function and initial performance goals. A proposed usage allocation policy is discussed and some initial problems being readied for solution on the NAS system are identified.

Peterson, V. L.↗