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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 523 records · Page 29

Nasa Hytec CMC Turbine Blade Durability

The objective of the CMC turbine blade durability program is to identify critical material and design parameters that affect durability of ceramic matrix composite (CMC) turbine blades. A baseline architecture for a cooled high-pressure turbine (HPT) CMC blade and accompanying sub-component test articles were developed with the intent to demonstrate through analysis and subcomponent testing how material and design parameters impact key failure modes. As part of this program, a notional architecture for a cooled CMC blade was matured through a design review rhythm to produce a blade test article containing the necessary features required for operation in an engine like environment. Further validation of the durability of these features were achieved through coupon and sub-component testing to demonstrate the durability of cooling hole configurations and blade attachment designs. Analytical methods were also used to evaluate the acceptability of the baseline blade test article architecture against relevant design requirements and identify abatement and recommended changes to key design drivers to improve component durability for future design iterations.

CMC, Blade↗

Upgrading Fermilab’s accelerator control system with ACORN

The Fermilab Accelerator Complex is the largest national user facility in the Office of High Energy Physics (DOE/HEP) program and the only national user facility operating at Fermilab. Fermilab serves as the host to the Long Baseline Neutrino Facility/Deep Underground Neutrino Experiment (LBNF/DUNE), the laboratory’s flagship project for neutrino science that is under construction. LBNF/DUNE will be powered by megawatt beams from an upgraded accelerator, the Proton Improvement Plan II (PIP-II) that will replace the laboratory’s aging linear accelerator with a new one based on superconducting radio-frequency cavities. The Accelerator Controls Operations Research Network (ACORN) Project will support LBNF/DUNE and PIP-II by modernizing the accelerator control system. The project is at the conceptual design phase and looking to achieve Critical Decision 1 (CD-1) later this year. The scope and structure of the project will be presented, along with an overview of how that has changed in the past year. Current design and technology choices will be shared. Specific challenges facing the project will be addressed, along with current thinking on solutions.

Roehrig, Christian [Fermilab]↗

Test plan pressure fed thrust chamber technology

Aerojet is developing the technology for the design of a reliable, low cost, efficient, and lightweight LOX/RP-1 pressure fed engine. This technology program is a direct result of Aerojet's liquid rocket booster (LRB) study and previous NASA studies that identified liquid engines using high bulk density hydrocarbon fuels as very attractive for a space transportation system (STS). Previous large thrust LOX/RP-1 engine development programs were characterized by costly development problems due to combustion instability damage. The combustion stability solution was typically obtained through trial and error methods of minimizing instability damage by degrading engine performance. The approach to this program was to utilize existing and newly developed combustion analysis models and design methodology to create a thrust chamber design with features having the potential of producing reliable and efficient operation. This process resulted in an engine design with a unique high thrust-per-element OFO triplet injector utilizing a low cost modular approach. Cost efficient ablative materials are baselined for the injector face and chamber. Technology demonstration will be accomplished through a hot fire test program using appropriately sized subscale hardware. This subscale testing will provide a data base to supplement the current industry data bank and to anchor and validate the applied analysis models and design methodology. Once anchored and validated, these analysis models and design methodology can be applied with greatly increased confidence to design and characterize a large scale pressure fed LOX/RP-1 thrust chamber. The objective of this test program is to generate a data base that can be used to anchor and validate existing analysis models and design methodologies and to provide early concept demonstration of a low cost, efficient LOX/RP-1 thrust chamber. Test conditions and hardware instrumentation were defined to provide data sufficient to characterize combustion stability, performance, and thermal operation over a wide thrust chamber throttling range.

Dunn, Glenn↗

The HYDROS mission: requirements and baseline system design

The HYDROS mission is under development by NASA as part of its Earth System Science Pathfinder program. HYDROS is designed to provide global maps of the Earth's soil moisture and freeze/thaw state every 2-3 days, for weather and climate prediction, water and carbon cycle studies, natural hazards monitoring, and national security applications.

radar↗

Baseline HSR Inlet and Engine Bay Cowl Seal Requirements

The two dimensinal bifurcated inlet, down selected for the HSR program, and the engine bay cowling consist of many sealing interfaces. The variable geometry characteristics of this inlet and the size of the propulsion system impose new sealing requirements for commercial transport aircraft. Major inlet systems requiring seal development and testing include the ramp system, the bypass/take-off system, and the inlet/engine interface. Engine bay cowling seal interfaces include the inlet/cowling interface, the keel split line, the hinge beam/engine bay cowling, and the nozzle/cowling interface. These seals have to withstand supersonic flight operating temperatures and pressures with typical commercial aircraft reliability and lives. The operating conditions and expected seal lives will be identified for the various interfaces. Boeing's SST seal development program will also be discussed.

Sandquist, David↗

Icing effects on aircraft stability and control determined from flight data: Preliminary results

The effects of airframe icing on the stability and control characteristics of the NASA DH-6 Twin Otter icing research aircraft were investigated by flight test. The flight program was developed to obtain the stability and control parameters of the DH-6 in a baseline ('uniced') configuration and an 'artificially iced' configuration for specified thrust conditions. Stability and control parameter identification maneuvers were performed over a wide range of angles of attack for wing flaps retracted (0 deg) and wing flaps partially deflected (10 deg). Engine power was adjusted to hold thrust constant at one of three thrust coefficients (C(sub T) = 0.14, C(sub T) = 0.07, C(subT) = 0.00). This paper presents only the pitching- and yawing-moment results from the flight test program. Stability and control parameters were estimated for the uniced and artificially iced configurations using a modified stepwise regression algorithm. Comparisons of the uniced and iced stability and control parameters are presented for the majority of the flight envelope. The artificial ice reduced the elevator and rudder control effectiveness by 12 percent and 8 percent respectively for the 0 deg flap setting. The longitudinal static stability was also decreased substantially (approximately 10 percent) because of the tail ice. Further discussion is provided to explain some of the effects of ice on the stability and control parameters.

Ratvasky, T. P.↗

Integration becomes the name of the OTV game

Since 1981, NASA has been supporting an Orbit Transfer Vehicle (OTV) propulsion technology development program which encompasses the efforts of three major engine manufacturers. A thrust variability ratio of 30:1 has been stipulated for the baseline 520 lbf-sec/lbm engines, in order to yield the versatility needed for low acceleration missions, orbit-transfer missions, and aeromaneuvering tasks. These goals may not be reachable either individually or collectively; the program supports generic technology benefitting all three engine concepts, as well as concept-specific technology. Engine/vehicle integration will determine the final configuration. The three engines under study differ as to turbomachinery types and operating speeds.

Garland, S.↗

Preliminary analysis of SSME baseline plume emissions

A review of current efforts to establish baseline emission levels from the SSME plume is presented. Recent data obtained under the Optical Plume Anomaly Detector program at the Technology Test Bed at MSFC is examined with an emphasis on interpretation of spectral and temporal features observed during nominal motor operation. In particular, the repeated appearance of Cr, Fe, Mn, Ca, and Li at engine startup and shutdown is discussed, and broadband attenuation due to scattering from water vapor is seen to complicate characterization of baseline levels. Also, emission from the combustion related specie OH, the underlying broadband continuum, and the Na impurity is discussed in relation to changes in Rated Power Level (RPL). Results from a theoretical spectral analysis of engine start-up activity is presented.

Wallace, T. L.↗

A VLBI variance-covariance analysis interactive computer program

An interactive computer program (in FORTRAN) for the variance covariance analysis of VLBI experiments is presented for use in experiment planning, simulation studies and optimal design problems. The interactive mode is especially suited to these types of analyses providing ease of operation as well as savings in time and cost. The geodetic parameters include baseline vector parameters and variations in polar motion and Earth rotation. A discussion of the theroy on which the program is based provides an overview of the VLBI process emphasizing the areas of interest to geodesy. Special emphasis is placed on the problem of determining correlations between simultaneous observations from a network of stations. A model suitable for covariance analyses is presented. Suggestions towards developing optimal observation schedules are included.

Bock, Y.↗

Ni-MH storage test and cycle life test

Gates Aerospace Batteries is conducting two long term test programs to fully characterize the NiMH cell technology for aerospace applications. The first program analyzes the effects of long term storage upon cell performance. The second program analyzes cycle life testing and preliminary production lot testing. This paper summarizes these approaches to testing the NiMH couple and culminates with initial storage and testing recommendations. Long term storage presents challenges to deter the adverse condition of capacity fade in NiMH cells. Elevated but stabilized pressures and elevated but stabilized end-of-charge voltages also appear to be a characteristic phenomenon of long term storage modes. However, the performance degradation is dependent upon specific characteristics of the metal-hydride alloy. To date, there is no objective evidence with which to recommend the proper method for storage and handling of NiMH cells upon shipment. This is particularly critical due to limited data points that indicate open circuit storage at room temperature for 60 to 90 days will result in irrecoverable capacity loss. Accordingly a test plan was developed to determine what method of mid-term to long-term storage will prevent irrecoverable capacity loss. The explicit assumption is that trickle charging at some rate above the self-discharge rate will prevent the irreversible chemical changes to the negative electrode that result in the irrecoverable capacity loss. Another premise is that lower storage temperatures, typically 0 C for aerospace customers, will impede any negative chemical reactions. Three different trickle charge rates are expected to yield a fairly flat response with respect to recoverable capacity versus baseline cells in two different modes of open circuit. Specific attributes monitored include: end-of-charge voltage, end-of-charge pressure, mid-point discharge voltage, capacity, and end-of-discharge pressure. Cycle life testing and preliminary production lot testing continue to dominate the overall technology development effort at GAB. The cell life test program reflects continuing improvements in baseline cell designs. Performance improvements include lower and more stable charge voltages and pressures. The continuing review of production lot testing assures conformance to the design criteria and expectations. This is especially critical during this period of transferring technology from research and development status to production.

Dell, R. Dan↗

Millimeter wave satellite concepts, volume 1

The identification of technologies necessary for development of millimeter spectrum communication satellites was examined from a system point of view. Development of methodology based on the technical requirements of potential services that might be assigned to millimeter wave bands for identifying the viable and appropriate technologies for future NASA millimeter research and development programs, and testing of this methodology with selected user applications and services were the goals of the program. The entire communications network, both ground and space subsystems was studied. Cost, weight, and performance models for the subsystems, conceptual design for point-to-point and broadcast communications satellites, and analytic relationships between subsystem parameters and an overall link performance are discussed along with baseline conceptual systems, sensitivity studies, model adjustment analyses, identification of critical technologies and their risks, and brief research and development program scenarios for the technologies judged to be moderate or extensive risks. Identification of technologies for millimeter satellite communication systems, and assessment of the relative risks of these technologies, was accomplished through subsystem modeling and link optimization for both point-to-point and broadcast applications.

Hilsen, N. B.↗

Multi-EVA communications system analysis

A communications concept is analyzed to establish requirements of a confident candidate system for space shuttle. Conceptual baseline configurations, EVA's-to-spacecraft via PCM/FDM and spacecraft-to-EVA via PAM/FM, and respective functional performance requirements are discussed. The baseline system is analyzed to determine link characteristics, EMI levels at various frequency bands, and determination of desirable spectrum. Selected L- and S-Band links are analyzed to ascertain signal design parameters. A trade-off is performed, which establishes L-Band frequency as the best compromise. The results of the analysis along with the reliability/safety aspects and physical characteristics of the candidate system, indicate that the initial baseline concept meets functional requirements, but is poor from standpoint of overall space shuttle program cost.

Source record↗

The NASA Quiet Engines.

The present status of the Quiet Engine Program is reviewed, and the future prospects suggested by recent quiet engine test results are discussed. Following a brief survey of noise sources, quiet engine design features, and the major elements of the Quiet Engine Program, a review is presented of specific quiet engine test that includes the two baseline quiet engines tested and flyover noise comparison results. It is shown that the application to future aircraft of the developed and demonstrated engine noise reduction technology can bring about a substantial reduction in aircraft noise levels. The minimization of the economic penalty associated with this noise reduction technology is being studied.

Ciepluch, C. C.↗

Permanent and separable aerospace tubing/ fitting evaluation program, volume 1

The tube fitting evaluation program was conducted to develop a standard overall test program including methods, procedures, and equipment as well as recommended test sequences for qualifying fitting/tubing assemblies. The program consisted of testing the MS flareless (separable) fitting and utilizing the results as baseline data from which all other fittings will be evaluated. Five separable designs and five permanent designs were tested in three sizes with two types of tubing materials. The basic design requirements were 4,000 psi operating pressure within the temperature range of minus 65 F to plus 450 F while also being compatible with 21-6-9 and titanium 3Al-2.5V tubing alloys.

Ursell, C. R.↗

The Space Shuttle Orbiter and aerodynamic testing

The concept of utilizing the Space Shuttle Orbiter as an aerodynamic flight research vehicle is discussed. The orbiter's planned flight frequency and its complex flight control system provide an unprecedented flight research potential. This paper defines the orbiter's flight environment and applicable baseline systems, their capabilities and limitations, as well as those instrument systems required to augment the baseline capability. These required systems, which are being developed under NASA's Orbiter Experiments Program (OEX) are the Aerodynamic Coefficient Identification Package (ACIP), Shuttle Entry Air Data System (SEADS), and the Shuttle Upper Atmosphere Mass Spectrometer (SUMS). Finally, the need for and capability of launching payloads from the orbiter to extend the research potential beyond the orbiter configuration and/or environment is defined.

Siemers, P. M., III↗

Study of aerodynamic technology for single-cruise engine V/STOL fighter/attack aircraft

A conceptual design analysis is performed on a single engine V/STOL supersonic fighter/attack concept powered by a series flow tandem fan propulsion system. Forward and aft mounted fans have independent flow paths for V/STOL operation and series flow in high speed flight. Mission, combat and V/STOL performance is calculated. Detailed aerodynamic estimates are made and aerodynamic uncertainties associated with the configuration and estimation methods identified. A wind tunnel research program is developed to resolve principal uncertainties and establish a data base for the baseline configuration and parametric variations.

Driggers, H. H.↗