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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 307 records · Page 17
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Electro optical system to measure strains at high temperature

The goals of this proposal were to develop a prototype of an electro-optics system for the measurement of strains in structures at high temperatures and to perform a test under field conditions. In the research task section, the topics addressed include: (1) correction of the effect of vibrations and thermal currents by means of an active compensation system; (2) reduction of the speckle noise by means of electronic filter and TV signal reconstruction circuit; (4) compensation of the rigid body motions by mounting the camera in a universal motion system; and (5) removal of phase errors left by the active compensation system by dynamic reading. In the design and construction section, the topics addressed include: (1) preliminary design; (2) final design; (3) software development; (4) signal conditioning; (5) data processing; (6) recorrelation of two holograms in the presence of rigid body motions; and (7) phase extraction using a computer generated image. Testing in the high temperature oven is also addressed.

Sciammarella, Cesar A.↗
NASA NTRS1993

Material requirements for the High Speed Civil Transport

Under NASA-sponsored High Speed Research (HSR) programs, the materials and processing requirements have been identified for overcoming the environmental and economic barriers of the next generation High Speed Civil Transport (HSCT) propulsion system. The long (2 to 5 hours) supersonic cruise portion of the HSCT cycle will place additional durability requirements on all hot section engine components. Low emissions combustor designs will require high temperature ceramic matrix composite liners to meet an emission goal of less than 5g NO(x) per Kg fuel burned. Large axisymmetric and two-dimensional exhaust nozzle designs are now under development to meet or exceed FAR 36 Stage III noise requirements, and will require lightweight, high temperature metallic, intermetallic, and ceramic matrix composites to reduce nozzle weight and meet structural and acoustic component performance goals. This paper describes and discusses the turbomachinery, combustor, and exhaust nozzle requirements of the High Speed Civil Transport propulsion system.

Stephens, Joseph R.↗
NASA NTRS2007

A Probabilistic System Analysis of Intelligent Propulsion System Technologies

NASA s Intelligent Propulsion System Technology (Propulsion 21) project focuses on developing adaptive technologies that will enable commercial gas turbine engines to produce fewer emissions and less noise while increasing reliability. It features adaptive technologies that have included active tip-clearance control for turbine and compressor, active combustion control, turbine aero-thermal and flow control, and enabling technologies such as sensors which are reliable at high operating temperatures and are minimally intrusive. A probabilistic system analysis is performed to evaluate the impact of these technologies on aircraft CO2 (directly proportional to fuel burn) and LTO (landing and takeoff) NO(x) reductions. A 300-passenger aircraft, with two 396-kN thrust (85,000-pound) engines is chosen for the study. The results show that NASA s Intelligent Propulsion System technologies have the potential to significantly reduce the CO2 and NO(x) emissions. The results are used to support informed decisionmaking on the development of the intelligent propulsion system technology portfolio for CO2 and NO(x) reductions.

Tong, Michael T.↗
NASA NTRS1985

DSN 34-meter Antenna Optics Analysis for Wideband SETI Investigations

A DSN 34-meter symmetric Cassegrain antenna configuration is examined for wideband use over the frequency range of 1 to 10 GHz, rather than only at the narrow-band operational design frequencies of 2.295 GHz (S-band) and 8.448 GHz (X-band). Aperture efficiency and surface efficiency are calculated as the components determining the gain of the antenna. Noise temperature contributions arise from the ground, atmosphere, and quadripod scattering. These components are calculated as a function of frequency elevation angle to determine a G/T (gain/system noise temperature) figure-of-merit for a nominal 34-meter antenna configuration. A computational method was developed which will enable design of a multi-horn antenna feed system to optimally cover the 1 to 10 GHz frequency range.

Slobin, S. D.↗
NASA NTRS1985

Advanced Moisture and Temperature Sounder (AMTS) baseline 5 study report

An Advanced Moisture and Temperature Sounder (AMTS) passive infrared atmospheric sounding system is described. Instrument requirements are developed. Parametric and scaling equations for a grating spectrometer instrument approach are developed which define detector noise limited performance in terms of instrument, orbit, and spatial coverage parameters. Instrument design criteria are developed and a baseline instrument design is presented. Error sources are identified and corresponding system error component values are estimated. Within narrow limits, the highest level of performance achievable with a stand alone infrared sounder using current state of the art technology is established. Additional trade offs necessary to establish a reasonably optimal system design in terms of performance, cost, and risk are identified.

Evans, N. L., Jr.↗
NASA NTRS1991

Caustic Singularities Of High-Gain, Dual-Shaped Reflectors

Report presents study of some sources of error in analysis, by geometric theory of diffraction (GTD), of performance of high-gain, dual-shaped antenna reflector. Study probes into underlying analytic causes of singularity, with view toward devising and testing practical methods to avoid problems caused by singularity. Hybrid physical optics (PO) approach used to study near-field spillover or noise-temperature characteristics of high-gain relector antenna efficiently and accurately. Report illustrates this approach and underlying principles by presenting numerical results, for both offset and symmetrical reflector systems, computed by GTD, PO, and PO/GO methods.

Galindo, Victor↗
NASA NTRS1995

EPOP Diagnostics and Data Acquisition

This paper describes the diagnostics that have been selected for the first flight of the Electric Propulsion Orbital Platform (EPOP-1), in which a 1.8 kW hydrazine arcjet will be flown and tested on the Wake Shield Facility. These diagnostics are: Langmuir probe measurements and video of the arcjet plume; three types of electromagnetic noise measurements; measurement of the voltage-current characteristic of the arc at different feed pressures; and measurement of other performance parameters such as pressures and temperatures of arcjet system components, thrust, and specific impulse. Also, the approach to data acquisition and control of the experiment is described.

Ruyten, W. M.↗
NASA NTRS2020

High-Resistivity Measurement System for Spacecraft Dielectrics

- Volume resistivity is a key material property needed for assessing the risk of electrostatic discharge (ESD) due to spacecraft charging. We have developed a volume resistivity test system capable of measuring volume resistivity ≥1019 Ω·cm in vacuum and at cryogenic temperatures. Key components of this new setup include a custom test fixture and very low noise battery voltage supply.

Chave, Robert↗
NASA NTRS2009

NASA Tech Briefs, November 2009

Topics covered include: Cryogenic Chamber for Servo-Hydraulic Materials Testing; Apparatus Measures Thermal Conductance Through a Thin Sample from Cryogenic to Room Temperature; Rover Attitude and Pointing System Simulation Testbed; Desktop Application Program to Simulate Cargo-Air-Drop Tests; Multimodal Friction Ignition Tester; Small-Bolt Torque-Tension Tester; Integrated Spacesuit Audio System Enhances Speech Quality and Reduces Noise; Hardware Implementation of a Bilateral Subtraction Filter; Simple Optoelectronic Feedback in Microwave Oscillators; Small X-Band Oscillator Antennas; Free-Space Optical Interconnect Employing VCSEL Diodes; Discrete Fourier Transform Analysis in a Complex Vector Space; Miniature Scroll Pumps Fabricated by LIGA; Self-Assembling, Flexible, Pre-Ceramic Composite Preforms; Flight-speed Integral Image Analysis Toolkit; Work Coordination Engine; Multi-Mission Automated Task Invocation Subsystem; Autonomously Calibrating a Quadrupole Mass Spectrometer; Determining Spacecraft Reaction Wheel Friction Parameters; Composite Silica Aerogels Opacified with Titania; Multiplexed Colorimetric Solid-Phase Extraction; Detecting Airborne Mercury by Use of Polymer/Carbon Films; Lattice-Matched Semiconductor Layers on Single Crystalline Sapphire Substrate; Pressure-Energized Seal Rings to Better Withstand Flows; Rollerjaw Rock Crusher; Microwave Sterilization and Depyrogenation System; Quantifying Therapeutic and Diagnostic Efficacy in 2D Microvascular Images; NiF2/NaF:CaF2/Ca Solid-State High-Temperature Battery Cells; Critical Coupling Between Optical Fibers and WGM Resonators; Microwave Temperature Profiler Mounted in a Standard Airborne Research Canister; Alternative Determination of Density of the Titan Atmosphere; Solar Rejection Filter for Large Telescopes; Automated CFD for Generation of Airfoil Performance Tables; Progressive Classification Using Support Vector Machines; Active Learning with Irrelevant Examples; A Data Matrix Method for Improving the Quantification of Element Percentages of SEM/EDX Analysis; Deployable Shroud for the International X-Ray Observatory; Improved Model of a Mercury Ring Damper; Optoelectronic pH Meter: Further Details; X-38 Advanced Sublimator; and Solar Simulator Represents the Mars Surface Solar Environment.

Source record↗
NASA NTRS2011

High Temperature Monitoring the Height of Condensed Water in Steam Pipes

An in-service health monitoring system is needed for steam pipes to track through their wall the condensation of water. The system is required to measure the height of the condensed water inside the pipe while operating at temperatures that are as high as 250 deg. C. The system needs to be able to make real time measurements while accounting for the effects of cavitation and wavy water surface. For this purpose, ultrasonic wave in pulse-echo configuration was used and reflected signals were acquired and auto-correlated to remove noise from the data and determine the water height. Transmitting and receiving the waves is done by piezoelectric transducers having Curie temperature that is significantly higher than 250 deg. C. Measurements were made at temperatures as high as 250 deg. C and have shown the feasibility of the test method. This manuscript reports the results of this feasibility study.

fluid height monitoring↗
NASA NTRS2009

Thermal Infrared Spectral Imager for Airborne Science Applications

An airborne thermal hyperspectral imager is under development which utilizes the compact Dyson optical configuration and quantum well infrared photo detector (QWIP) focal plane array. The Dyson configuration uses a single monolithic prism-like grating design which allows for a high throughput instrument (F/1.6) with minimal ghosting, stray-light and large swath width. The configuration has the potential to be the optimal imaging spectroscopy solution for lighter-than-air (LTA) vehicles and unmanned aerial vehicles (UAV) due to its small form factor and relatively low power requirements. The planned instrument specifications are discussed as well as design trade-offs. Calibration testing results (noise equivalent temperature difference, spectral linearity and spectral bandwidth) and laboratory emissivity plots from samples are shown using an operational testbed unit which has similar specifications as the final airborne system. Field testing of the testbed unit was performed to acquire plots of apparent emissivity for various known standard minerals (such as quartz). A comparison is made using data from the ASTER spectral library.

QWIP↗
NASA NTRS2018

In-Flight Verification and Validation of Colloid Microthruster Performance

Colloid Micronewton Thrusters (CMNTs) use an electrospray to provide precision spacecraft position and pointing control. They were demonstrated in space for the first time as part of NASA’s Space Technology 7 (ST7) payload hosted by the European Space Agency’s (ESA’s) LISA Pathfinder (LPF) technology demonstration mission in January, 2016. CMNTs were the actuator in the disturbance reduction system (DRS) that provided drag-free operation of the LPF spacecraft, which will be necessary for future gravity wave observatories such as ESA’s Laser Interferometer Space Antenna (LISA) mission, currently in Phase A and scheduled for launch in 2034. The CMNT technology met performance requirements operating at 5-30 µN of thrust with 0.1 µN resolution and ≤0.1 µN/ÖHz thrust noise to deliver the required nanometer-level precision spacecraft control measured by the gravitational reference sensor (GRS) in the ESA LISA Technology Package (LTP). The performance of seven of the eight CMNTs in flight was consistent with ground test results, and as a system, all eight thrusters met mission-level performance requirements. The colloid microthruster performance model of thrust and thrust noise as a function of operational parameters (i.e. beam current, voltage, temperature, etc.) was validated in flight over a wide range of conditions. A model and simulation of the thruster control algorithm was developed and validated with flight data to predict thrust noise. This capability is important for future missions because it relates directly to the acceleration noise on the test masses, which provide the gravity wave measurements. The CMNT thruster model data and validation with LISA Pathfinder/ST7-DRS flight experiments are presented in this paper.

"O'Donnell, James"↗
NASA NTRS2022

Impact of Future Low-Emissions Combustor Technology on Acoustic Scaling Laws

The overall goal of a recent research project at the Raytheon Technologies Research Center, under National Aeronautics and Space Administration sponsorship, was to develop a first-ofits-kind database of detailed unsteady measurements characterizing noise sources of far-term advanced low-emissions aero-combustors. The program addressed the need for fundamental combustion-noise experiments which, in the near term, enable improvements to reduced-order models for use in system level noise assessments at the preliminary design stage for advanced air transport vehicles. In addition, optical measurement techniques were refined and validated for usage at the higher pressures and temperatures relevant to future combustor designs. In the long term, results from this program can be utilized to validate high-fidelity prediction methods suited for detailed multi-disciplinary acoustics/emissions combustor design. This paper concentrates on one aspect of the overall project, namely an examination of the legacy scaling laws for broadband combustor noise.

aeroacoustics, turbomachinery noise, combustor noi↗
NASA NTRSDate not supplied

Impact of Future Low-Emissions Combustor Technology on Acoustic Scaling Laws

The work is a summary and further analysis of unlimited-rights acoustic data acquired under NRA Contract NNC16CA39C (September 2016 - November2019) with United Technologies (now Raytheon Technologies) Research Center, East Hartford, Connecticut. NASA/CR-20205011099/VOL1, https://ntrs.nasa.gov/citations/20205011099. The overall goal of the Contract was to develop a first-of-its- kind database of detailed unsteady measurements characterizing noise sources of far-term advanced low-emissions aero-combustors. The program addressed the need for fundamental combustion-noise experiments which, in the near term, enable improvements to reduced-order models for use in system level noise assessments at the preliminary design stage for advanced air transport vehicles. In addition, optical measurement techniques were refined and validated for usage at the higher pressures and temperatures relevant to future combustor designs. In the long term, results from this program can be utilized to validate high-fidelity prediction methods suited for detailed multi-disciplinary acoustics/emissions combustor design. This presentation concentrates on one aspect of the overall project, namely an examination of the legacy scaling laws for broadband combustor noise.

aeroacoustics, turbomachinery noise, combustor noi↗
NASA NTRS1990

CARS temperature measurements in a hypersonic propulsion test facility

Static-temperature measurements performed in a reacting vitiated air-hydrogen Mach-2 flow in a duct in Test Cell 2 at NASA LaRC by using a coherent anti-Stokes Raman spectroscopy (CARS) system are discussed. The hypersonic propulsion Test Cell 2 hardware is outlined with emphasis on optical access ports and safety features in the design of the Test Cell. Such design considerations as vibration, noise, contamination from flow field or atmospheric-borne dust, unwanted laser- and electrically-induced combustion, and movement of the sampling volume in the flow are presented. The CARS system is described, and focus is placed on the principle and components of system-to-monochromator signal coupling. Contour plots of scramjet combustor static temperature in a reacting-flow region are presented for three stations, and it is noted that the measurements reveal such features in the flow as maximum temperature near the model wall in the region of the injector footprint.

Jarrett, O., Jr.↗
NASA NTRS1979

Studies of the acoustic transmission characteristics of coaxial nozzles with inverted velocity profiles: Comprehensive data report

The efficiency of internal noise radiation through a coannular exhaust nozzle with an inverted velocity profile was studied. A preliminary investigation was first undertaken (1) to define the test parameters which influence the internal noise radiation; (2) to develop a test methodology which could realistically be used to examine the effects of the test parameters; and (3) to validate this methodology. The result was the choice of an acoustic impulse as the internal noise source in the jet nozzles. Noise transmission characteristics of a coannular nozzle system were then investigated. In particular, the effects of fan convergence angle, core extension length to annulus height ratio and flow Mach numbers and temperatures were studied. Relevant spectral data only is presented in the form of normalized nozzle transfer function versus nondimensional frequency.

Dean, P. D.↗
NASA NTRS1979

Studies of the acoustic transmission characteristics of coaxial nozzles with inverted velocity profiles, volume 1

The efficiency of internal noise radiation through coannular exhaust nozzle with an inverted velocity profile was studied. A preliminary investigation was first undertaken to: (1) define the test parameters which influence the internal noise radiation; (2) develop a test methodology which could realistically be used to examine the effects of the test parameters; (3) and to validate this methodology. The result was the choice of an acoustic impulse as the internal noise source in the in the jet nozzles. Noise transmission characteristics of a nozzle system were then investigated. In particular, the effects of fan nozzle convergence angle, core extention length to annulus height ratio, and flow Mach number and temperatures were studied. The results are presented as normalized directivity plots.

Dean, P. D.↗
NASA NTRS1986

Waveguide submillimeter mixers

A waveguide Schottky barrier diode mixer, which in preliminary tests has yielded a single sideband receiver noise temperature of 4300 K at 692 GHz, when cooled to 77 K is presented. Further refinements and operation at 20 K should produce a significant improvement in performance. From a system point of view, the very high efficiency of the radiation pattern produced by the conical feedhorn with cylindrical corrector mirror enhances the effective sensitivity by a factor of 1.5 to 2 compared to open-structure corner-reflector systems. A second-harmonic mixer for 557 GHz, also in the fundamental mode rectangular waveguide was developed. When combined with a frequency-tripled Gunn oscillator, this makes an extremely compact and lightweight submillimeter radiometer.

Goldsmith, Paul F.↗