Dispersion of heat and humidity from atmospheric spray-cooling systems
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Weinstein, H.↗
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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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Simplified tooling for spray masking
Tooling technique involves positioning tiles within acrylic plastic masking frames that attach magnetically to holding fixture. Plastics are "magnetized" with adhesive mangetic-rubber strips. Technique is simpler and less expensive than conventional methods. L-shaped masks are easily cut and altered.
Dinbar, B. J.↗
A plasma-sprayed valve coating
Need to reduce wear on nickel alloy seats and poppets for Space Shuttle main engine led to fused cobalt/tungsten carbide coating. Coating, which is dense, wear-resistant, and nonporous, can be applied in controlled amounts to various substrate configurations. Ease of application to parts with intricate shapes and contours should make coating useful in automotive and aircraft manufacturing.
Brennan, A.↗
Fuel spray data with LDV
Droplet size and two component velocities in the severe environment of an operating gas turbine combustor system can be measured simultaneously using the solar laser morphokinetomer (SLM) which incorporates the following capabilities: (1) measurement of a true two-dimensional velocity vector with a range of + or - (0.01-200 m/sec); (2) measurement of particle size (range 5 to 300 micron m) simultaneously with the measurement of velocity; (3) specification of probe volume position coordinates with a high degree of accuracy (+ or - 0.5 mm); (4) immediate on-line data checks; and (5) rapid computer storage of acquired data. The optical system of the SLM incorporates an ultrasonic beam splitter to allow the measurement of a two-dimensional velocity vector simultaneously with particle size. A microprocessor with a limited storage capability permits immediate analysis of test data in the test cell.
Rohy, D. A.↗
The development of methods for predicting and measuring distribution patterns of aerial sprays
The capability of conducting scale model experiments which involve the ejection of small particles into the wake of an aircraft close to the ground is developed. A set of relationships used to scale small-sized dispersion studies to full-size results are experimentally verified and, with some qualifications, basic deposition patterns are presented. In the process of validating these scaling laws, the basic experimental techniques used in conducting such studies, both with and without an operational propeller, were developed. The procedures that evolved are outlined. The envelope of test conditions that can be accommodated in the Langley Vortex Research Facility, which were developed theoretically, are verified using a series of vortex trajectory experiments that help to define the limitations due to wall interference effects for models of different sizes.
Ormsbee, A. I.↗
Spraying suspensions uniformly
With head on each of its ends, bolt can be disengaged from its blind side. Bolt has conventional hexagonal head on one end and smaller hexagonal head on its threaded end. Since reduced head is smaller than bolt diameter, it does not interfere with insertion of bolt shank in bolthole. However, it can be turned by wrench to release bolt from its blind (threaded) end. Bolt should be tethered on its large-head end so that it does not drop away from assembly.
Prasthofer, W. P.↗
Microstructure and mechanical properties of bulk and plasma-sprayed y2O3-partially stabilized zirconia
Bulk 8.0 weight percent yttria partially stabilied zirconia (PSZ) was studied by light microscopy, transmission electron microscopy, X-ray analysis, microhardness testing, and fracture toughness testing. The as received PSZ contained spheroidal and grain boundary precipitates up to 4 micrometers in size. Spheroids up to 1.26 micrometers were metastable tetragonal; large spheroids were monoclinic. Grinding the PSZ into powder did not cause a significant amount of tetragonal to transform to monoclinic. This indicates that transformation toughness is not a significant mechanism in PSZ. Aging the PSZ at 1500 C caused the fine tetragonal precipitates to grow from 0.06 to 0.12 micrometers, in 250 minutes. A peak hardness of 1400 kg/sq mm was attained after 50 minutes. Solution annealing and quenching the as received PSZ eliminated the large precipitates, but fine tetragonal precipitates reformed on quenching. Aging at 1500 C caused the fine 0.02 micrometers tetragonal precipitates to grow into plates about 0.10 by 0.50 micrometers. A peak hardness of 1517 kg/sq mm was obtained after 250 minutes. On further aging, monoclinic percipitates formed along grain boundaries. The fracture toughness of the aged and unaged solution annealed and quenched PSZ was found to be between 2 and 3 MN /square root of m cubed. This range of fracture toughness is consistent with PSZ's that do not undergo transformation toughening.
Valentine, P. G.↗
The development of methods for predicting and measuring distribution patterns of aerial sprays
A set of relationships used to scale small sized dispersion studies to full size results are experimentally verified and, with some qualifications, basic deposition patterns are presented. In the process of validating these scaling laws, the basic experimental techniques used in conducting such studies both with and without an operational propeller were developed. The procedures that evolved are outlined in some detail. The envelope of test conditions that can be accommodated in the Langley Vortex Research Facility, which were developed theoretically, are verified using a series of vortex trajectory experiments that help to define the limitations due to wall interference effects for models of different sizes.
Ormsbee, A. I.↗
Comparative evaluation of insulating properties of plasma-sprayed ceramic coatings
A simple method for evaluating the thermal insulating capability of ceramic coatings was devised. It is based on monitoring the temperature of the uncoated back surface of a thin superalloy disk while its front surface, coated with the ceramic material, is exposed to the high-temperature environment of an electric muffle furnace. The results obtained indicate that zirconia containing 8 wt% Y2O3 is a better thermal insulator than barium zirconate or calcium orthosilicate.
Zaplatynsky, I.↗
Cost effective, high throughput, junction formation techniques using spray-on dopants
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Chitre, S. R.↗
Kinematical analysis of flare spray ejecta observed in the corona
Observations in H-alpha, soft X-ray, white light and radio wavelengths are used to track cool and hot material from limb de-occultation to the extent of six solar radii. The kinematics and thermodynamics of the internal material are determined, along with the overall mass and energy budget of the event. It is found that the majority of the mass and energy is linked with the coronal material, but at least 20% of the ejected mass originated as near-surface prominence material, leading to the conclusions that the upper part of the prominence was being heated to coronal temperatures as it rose through the corona. Evidence was found that a moving type IV burst, indicative of strong magnetic fields, was associated with the upper part of the prominence, and the observations are judged to be most consistent with magnetic propulsion models of coronal transients.
Webb, D. F.↗
A laser tomographic investigation of liquid fuel sprays
(Previously announced in STAR as N80-17399)
Yule, A. J.↗
Phase stability in plasma-sprayed, partially stabilized zirconia-yttria
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Miller, R. A.↗
Conductive Plasma-Sprayed Coatings
Normal emittance of oxidized titanium foil used as plume shields at high temperature significantly increased by plasma coating with specific ceramic materials.
Hribar, V. F.↗
Laser surface fusion of plasma sprayed ceramic turbine seals
The thermal shock resistance of a ceramic layer is improved. An improved abradable lining that is deposited on a shroud forming a gas path seal in turbomachinery is emphasized. Improved thermal shock resistance of a shroud is effective through the deliberate introduction of 'benign' cracks. These are microcracks which will not propagate appreciably upon exposure to the thermal shock environment in which a turbine seal must function. Laser surface fusion treatment is used to introduce these microcracks. The ceramic surface is laser scanned to form a continuous dense layer. As this cools and solidifies, shrinkage results in the formation of a very fine crack network. The presence of this deliberately introduced fine crack network precludes the formation of a catastrophic crack during thermal shock exposure.
Wisander, D. W.↗
Plasma-sprayed self-lubricating coatings
One of the most important criterion for acceptable commercial application of a multiple phase composition is uniformity and reproducibility. This means that the performance characteristics of the coat - e.g., its lubricating properties, bond strength to the substrate, and thermal properties - can be readily predicted to give a desired performance. The improvement of uniformity and reproducibility of the coats, the oxidation behavior at three temperature ranges, the effect of bond coat and the effect of preheat treatment as measured by adhesive strength tests, coating examination procedures, and physical property measurements were studied. The following modifications improved the uniformity and reproducibility: (1) changes and closer control in the particle size range of the raw materials used, (2) increasing the binder content from 3.2% to 4.1% (dried weight), and (3) analytical processing procedures using step by step checking to assure consistency.
Nakamura, H. H.↗
Correlation of compressive stress with spalling of plasma sprayed ceramic materials
Ceramics on metal substrates for potential use as high temperature seals or other applications are exposed to forces originating from differences in thermal expansion between the ceramic and the metal substrate. This report develops a relationship between the difference in expansion of the ceramic and the substrate, defines conditions under which shear between the ceramic and the substrate occurs, and those under which bending forces are produced in the ceramic. The off-axis effect of compression forces resulting from high temperature plastic flow of the ceramic producing buckling of the ceramic is developed. Shear is associated with the edge or boundary stresses on the component while bending is associated with the distortion of an interior region. Both modes are significant in predicting life of the ceramic.
Mullen, R. L.↗
Fuel Spray Diagnostics
Fundamental experimental data base for turbulent flow mixing models is provided and better prediction of the more complex turbulent chemical reacting flows. Analytical application to combustor design is provided and a better fundamental understanding of the combustion process.
Humenik, F. M.↗