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Results for “Optical measurement”

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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Optical Measurements on Solid Specimens of Solid Rocket Motor Exhaust and Solid Rocket Motor Slag

Samples of aluminum slag were investigated to aid the Earth Science and Applications Division at the Marshall Space Flight Center (MSFC). Alumina from space motor propellant exhaust and space motor propellant slag was examined as a component of space refuse. Thermal emittance and solar absorptivity measurements were taken to support their comparison with reflectance measurements derived from actual debris. To determine the similarity between the samples and space motor exhaust or space motor slag, emittance and absorbance results were correlated with an examination of specimen morphology.

Roberts, F. E., III↗
NASA NTRS1992

Experiments on the enhancement of compressible mixing via streamwise vorticity. I - Optical measurements

The present study was initiated in an attempt to increase the compressible mixing rate of a supersonic jet injected into a co-flowing supersonic stream by adding streamwise vorticity to the injected flow. This flowfield was imaged using the planar laser scattering technique, and mixing rates were derived entirely from captured images. The results of this image analysis indicate that increases in mixing rate of up to 60 percent are possible through the addition of streamwise vorticity. Furthermore, the degree of mixing enhancement appears to be dependent on the amount of swirl added. Analysis of the instantaneous turbulent structure suggests that this increase in mixing is due to a modification of the largest turbulent structures in the mixing layer.

Naughton, J. W.↗
NASA NTRS1994

Optical Measurement Of Propfan Deflections

Optoelectronic system measures deflections of rotating propfan. In addition to 0.5-mW HeNe lasers, system includes Schottky-barrier photodetectors, neutral-density filters, signal amplifiers, output-signal-recording device, and digitizer. Laser beam passes through plane of rotation of propfan blades. Beam is one of three that measure displacements at different blade sections. Additional laser beam at bottom generates shaft-rotation timing signal.

Ramsey, John K.↗
NASA NTRS2000

Optical Measurement of the Speed of Sound in Air Over the Temperature Range 300-650 K

Using laser-induced thermal acoustics (LITA), the speed of sound in room air (1 atm) is measured over the temperature range 300-650 K. Since the LITA apparatus maintains a fixed sound wavelength as temperature is varied, this temperature range simultaneously corresponds to a sound frequency range of 10-15 MHz. The data are compared to a published model and typically agree within 0.1%-0.4% at each of 21 temperatures.

Hart, Roger C.↗
NASA NTRS2000

Optical Measurement and Visualization in High-Pressure, High-Temperature, Aviation Gas Turbine Combustors

Planar laser-induced fluorescence (PLIF), planar Mie scattering (PMie), and linear (1-D) spontaneous Raman scattering are applied to flame tube and sector combustors that burn Jet-A fuel at a range of inlet temperatures and pressures that simulate conditions expected in future high-performance civilian gas turbine engines. Chemiluminescence arising from C2 in the flame was also imaged. Flame spectral emissions measurements were obtained using a scanning spectrometer. Several different advanced concept fuel injectors were examined. First-ever PLIF and chemiluminescence data are presented from the 60-atm Gas turbine combustor facility.

Hicks, Yolanda R.↗
NASA NTRS2004

Spatio-Temporal Distribution of Particulate and CDOM in the Mississippi River Bight (MRB) from Optical Measurements

NASA's projects for the Mississippi River Coastal Margin Study include Mississippi River Interdisciplinary Research (MiRIR) and NASA Experimental Program to Stimulate Competitive Research (EPSCoR). These projects, undertaken with the help of Tulane University and the Louisiana Universities Marine Consortium (LUMCON) sampled water in the Gulf of Mexico to measure colored dissolved organic matter (CDOM). This viewgraph presentation contains images of each program's sampling strategy and equipment.

D'Sa, Eurico↗
NASA NTRS2016

Application of Optical Measurement Techniques During Stages of Pregnancy: Use of Phantom High Speed Cameras for Digital Image Correlation (D.I.C.) During Baby Kicking and Abdomen Movements

Paired images were collected using a projected pattern instead of standard painting of the speckle pattern on her abdomen. High Speed cameras were post triggered after movements felt. Data was collected at 120 fps -limited due to 60hz frequency of projector. To ensure that kicks and movement data was real a background test was conducted with no baby movement (to correct for breathing and body motion).

Gradl, Paul↗
NASA NTRSDate not supplied

Utilizing Radiocarbon and Thermo-optical Measurements to Quantify Source Contributions for Aircraft Engine Particulate Emissions

Recent technological advancements in aircraft engine technology and fuel sources have promising potential for reducing particulate emissions from aircraft engines. During the 2022 Boeing ecoDemonstrator ground-based field campaign, particle and trace gas emissions were sampled for four different fuels, including 100% sustainable aviation fuel (SAF), petroleum-based Jet A fuel, petroleum-based Jet A low sulfur fuel, and a SAF blend. Particulate emissions were collected on quartz microfiber filters and analysed for their radiocarbon content and their elemental carbon (EC) and organic carbon (OC) concentrations. In addition, the radiocarbon content of Jet A fuel, SAF, and aircraft engine oil was also measured. We used the radiocarbon content of the particulate emissions samples and source end members to quantify the relative contribution from engine oil and fuel to carbonaceous aerosol emissions. The results from this study can be used to understand how the implementation of technological advancements in aircraft engine technology and fuel sources will likely impact future aircraft particulate emissions.

Liz Wiggins↗
DOE OSTI2022

Method and apparatus for measuring optical pulses

A pulse analysis system or method includes a frequency filter that receives an ultrafast pulse under test and disperses the pulse under test over a frequency range. The frequency filter separates the pulse under test into component frequency slices and provides the frequency slices to a detector coupled to a digitizer, which processes the digitized signal and collects a sonogram characteristic of the pulse under test. The frequency slices are arranged to overlap. Ptychography is performed on the sonogram to obtain characteristics of the pulse under test.

Kane, Daniel J.↗