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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

Thermokinetics and combustion phenomena in nonflowing gaseous systems - An invited review.

The current status of our understanding of combustion phenomena observed in nonflowing premixed gaseous systems is reviewed. The phenomena include slow oxidation, explosion, multiple ignition, oscillatory oxidation, as well as photolytic phenomena. Detailed experimental data on each of these phenomena are given, and analytical methods of analyzing them are outlined. The correlation between theory and experiment is studied for several special cases.

Berlad, A. L.↗
NASA NTRS1972

Temperature-dependent transmission and self-indication measurements upon depleted U in the unresolved region

Neutron transmission and self-indication ratio measurements have been carried out at the RPI LINAC on depleted U up to 100 KeV in order to investigate the temperature dependence of resonance self-shielding. These measurements were performed at three sample temperatures (77 deg k, 295 deg k, and 973 deg k) and with sample thicknesses ranging from 0.0076 to 0.0621 atom/barn. Both stochastic sampling and analytical methods have been used to interpret these data. Average resonance parameters have been obtained and temperature dependence as well as sample thickness dependence of the data have been extensively studied.

Byoun, T. Y.↗
NASA NTRS1973

Analysis of fatigue, fatique-crack propagation, and fracture data

Analytical methods have been developed for consolidation of fatigue, fatigue-crack propagation, and fracture data for use in design of metallic aerospace structural components. To evaluate these methods, a comprehensive file of data on 2024 and 7075 aluminums, Ti-6A1-4V, and 300M and D6Ac steels was established. Data were obtained from both published literature and unpublished reports furnished by aerospace companies. Fatigue and fatigue-crack-propagation analyses were restricted to information obtained from constant-amplitude load or strain cycling of specimens in air at room temperature. Fracture toughness data were from tests of center-cracked tension panels, part-through crack specimens, and compact-tension specimens.

Jaske, C. E.↗
NASA NTRS1973

Engineering report. Part 2: NASA wheel and brake material tradeoff study for space shuttle type environmental requirements

The study included material selection and trade-off for the structural components of the wheel and brake optimizing weight vs cost and feasibility for the space shuttle type application. Analytical methods were used to determine section thickness for various materials, and a table was constructed showing weight vs. cost trade-off. The wheel and brake were further optimized by considering design philosophies that deviate from standard aircraft specifications, and designs that best utilize the materials being considered.

Bok, L. D.↗
NASA NTRS1974

Interlaboratory comparison of chemical analysis of uranium mononitride

Analytical methods were established in which the critical variables were controlled, with the result that acceptable interlaboratory agreement was demonstrated for the chemical analysis of uranium mononitride. This was accomplished by using equipment readily available to laboratories performing metallurgical analyses. Agreement among three laboratories was shown to be very good for uranium and nitrogen. Interlaboratory precision of + or - 0.04 percent was achieved for both of these elements. Oxygen was determined to + or - 15 parts per million (ppm) at the 170-ppm level. The carbon determination gave an interlaboratory precision of + or - 46 ppm at the 320-ppm level.

Merkle, E. J.↗
NASA NTRS1973

The effects of shot-peening residual stresses on the fracture and crack growth properties of D6AC steel

The fracture strength and cyclic crack-growth properties of surface-flawed, shot-peened D6AC steel plate were investigated. For short crack lengths (up to 1.5mm) simple linear elastic fracture mechanics - based only on applied loading - did not predict the fracture strengths. Also, Paris' Law for cyclic crack growth did not correlate the crack-growth behavior. To investigate the effect of shot-peening, additional fracture and crack-growth tests were performed on material which was precompressed to remove the residual stresses left by the shot-peening. Both tests and analysis show that the shot-peening residual stresses influence the fracture and crack-growth properties of the material. The analytical method of compensating for residual stresses and the fracture and cyclic crack-growth test results and predictions are presented.

Elber, W.↗
NASA NTRS1974

Assessment of an analytical procedure for predicting supersonic ejector nozzle performance

The ability of analysis to predict ejector nozzle characteristics over a wide range of conditions and to study the relation between design parameters and performance is assessed. The analytical method investigated provided an accurate and economical method for predicting the performance of supersonic ejector nozzles. The factors which had the greatest influence over ejector nozzle behavior were those which influenced the initial expansion and recompression process.

Anderson, B. H.↗
NASA NTRS1974

Chemiluminescent measurement of atmospheric acid

The design and construction of a gas phase acid sensitive analyzer are reported. These studies showed that the chemical system was a practical analytical method. A complete instrument was developed and prepared for field testing. A Titan 3-C rocket was scheduled for launching on February 11, 1974. Through preparations made by NASA Langley the instrument was set up to monitor the acid concentration in the rocket exhaust. Due to adverse wind conditions no acid was detected. This entire trip is described in detail.

Stedman, D. H.↗
NASA NTRS1974

Status of two studies on active control of aeroelastic response at NASA Langley Research Center

The application of active control technology to the suppression of flutter was successfully demonstrated during two recent studies in the Langley transonic dynamics tunnel. The first study involved the implementation of an aerodynamic-energy criterion, using both leading- and trailing-edge controls, to suppress flutter of a simplified delta-wing model. Use of this technique resulted in an increase in the flutter dynamic pressure of approximately 12 percent for this model at a Mach number of 0.9. Analytical methods used to predict the open- and closed-loop behavior of the model are also discussed. The second study, which is a joint effort with the Air Force Flight Dynamics Laboratory, was conducted to establish the effect of active flutter suppression on a model of the Boeing B-52 Configured Vehicle (CCV). Some preliminary results of this study indicate significant improvements in the damping associated with the critical flutter mode.

Abel, I.↗
NASA NTRS1974

Calibration and evaluation of Skylab altimetry for geodetic determination of the geoid

The author has identified the following significant results. An analytical method for geodetic computation of the marine geoid (the geoid in the oceans) from satellite altimetry is developed and validated with data from Skylab mission SL-2. The criteria for achieving accurate scale and orientation of satellite altimetry geoid are shown to require marine geodetic control to offset systematic errors in the orbit (orientation is completely orbit dependent) and the altimeter data.

Mourad, A. G.↗
NASA NTRS1974

An assessment of separable fluid connector system parameters to perform a connector system design optimization study

The key to optimization of design where there are a large number of variables, all of which may not be known precisely, lies in the mathematical tool of dynamic programming developed by Bellman. This methodology can lead to optimized solutions to the design of critical systems in a minimum amount of time, even when there are a great number of acceptable configurations to be considered. To demonstrate the usefulness of dynamic programming, an analytical method is developed for evaluating the relationship among existing numerous connector designs to find the optimum configuration. The data utilized in the study were generated from 900 flanges designed for six subsystems of the S-1B stage of the Saturn 1B space carrier vehicle.

Prasthofer, W. P.↗
NASA NTRS1974

Transient cooling of solid bodies of classical form by radiation

An approximate analytic method is presented for analysis of the unsteady process of radiative cooling of solid bodies of classical form. The nonlinear heat transfer problem is solved by the cascade linearization technique with use of the iteration method. Comparison of the results obtained even in the first approximation with the available numerical solutions indicates adequate engineering accuracy of the proposed technique.

Novikov, V. S.↗
NASA NTRS1974

Role of man in flight experiment payloads, phase 1

The identification of required data for studies of Spacelab experiment functional allocation, the development of an approach to collecting these data from the payload community, and the specification of analytical methods necessary to quantitatively determine the role of man in specific Spacelab experiments are presented. A generalized Spacelab experiment operation sequence was developed, and the parameters necessary to describe each signle function in the sequence were identified. A set of functional descriptor worksheets were also drawn up. The methodological approach to defining the role of man was defined as a series of trade studies using a digial simulation technique. The tradeoff variables identified include scientific crew size, skill mix, and location. An existing digital simulation program suitable for the required analyses was identified and obtained.

Malone, T. B.↗
NASA NTRS1974

Skylab extravehicular mobility unit thermal simulator

The analytical methods, thermal model, and user's instructions for the Skylab Extravehicular Mobility Unit (SEMU) routine are presented. This digital computer program was developed for detailed thermal performance predictions of the SEMU on the NASA-JSC Univac 1108 computer system. It accounts for conductive, convective, and radiant heat transfer as well as fluid flow and special component characterization. The program provides thermal performance predictions for a 967 node thermal model in one thirty-sixth (1/36) of mission time when operated at a calculating interval of three minutes (mission time). The program has the operational flexibility to: (1) accept card or magnetic tape data input for the thermal model describing the SEMU structure, fluid systems, crewman and component performance, (2) accept card and/or magnetic tape input of internally generated heat and heat influx from the space environment, and (3) output tabular or plotted histories of temperature, flow rates, and other parameters describing system operating modes.

Hixon, C. W.↗
NASA NTRS1974

Analysis of impingement heat transfer for two parallel liquid-metal slot jets

An analytical method is developed for determining heat transfer by impinging liquid-metal slot jets. The method involves mapping the jet flow region, which is bounded by free streamlines, into a potential plane where it becomes a uniform flow in a channel of constant width. The energy equation is transformed into potential plane coordinates and is solved in the channel flow region. Conformal mapping is then used to transform the solution back into the physical plane and obtain the desired heat-transfer characteristics. The analysis given here determines the heat-transfer characteristics for two parallel liquid-metal slot jets impinging normally against a uniformly heated flat plate. The liquid-metal assumptions are made that the jets are inviscid and that molecular conduction is dominating heat diffusion. Wall temperature distributions along the heated plate are obtained as a function of spacing between the jets and the jet Peclet number.

Siegel, R.↗
NASA NTRS1974

Hydrocarbons identified in extracts from estuarine water accommodated no. 2 fuel oil by gas chromatography-mass spectrometry

Results are presented on a computerized gas chromatograph-mass spectrometer analysis of methylene chloride and n-heptane extracts of a No. 2 fuel oil accommodated estuarine water sample. The analytical method is briefly described, and the limitations on the identifications are categorized. Some attempt was made to determine major and trace constituents in the water accommodate. Altogether 66 hydrocarbon compounds were identified specifically, and 75 compounds were partially identified. Seven compounds could be recognized as major constituents of the water accommodated oil and ten were present only as traces. The aromatic compounds found were alkyl benzenes, naphthalene, tetralin, indane, biphenyl, fluorene, anthracene, and some of their alkyl substituted isomers in the range of carbon numbers C7 to C15. Four n-alkanes, C10 to C13, were found along with four other assorted hydrocarbons.

Lewis, B. W.↗
NASA NTRS1973

Turbine noise generation and suppression

An analytical method for the prediction of turbine generated noise is discussed. The method links the duct acoustic modes with the turbomachinery aerodynamics. The results of the analysis are compared with turbine component and engine results. Component data on the effects of the variation of axial spacing between blade rows on turbine aerodynamics and acoustics are presented. The results of an experimental evaluation of the relative importance of turbine noise on highly suppressed bypass turbofans are discussed. The development of high temperature acoustic treatment and its application to high bypass turbofans are presented.

Benzakein, M. J.↗
NASA NTRS1973

Evaluation of digitally corrected ERTS imagery

Utilizing all digital processing techniques, precision rectified ERTS multispectral imagery have been produced. Precision geometric correction is accomplished by: (1) utilizing a low order piecewise approximation to the image distortions; (2) incorporating spacecraft attitude refinement derived from ground control points utilized in a Kalman filter; (3) utilizing interpolation techniques which preserve value and slope continuity in the image data. Imagery produced is represented in a UTM projection, and has been evaluated for precision by statistical and analytical methods. Extrapolations to modest size computers indicate good throughput with no sacrifice in precision.

Rifman, S. S.↗