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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 1,729 records · Page 96
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Structure and function of an inorganic-organic separator for electrochemical cells: Preliminary study

The structure of a new separator material for electrochemical cells has been investigated. Investigation into details of the separator structure showed it to be multilayered and to consist mainly of a quasi-impervious organic skin, a porous region of mixed organic and inorganic material, and an area of nonuniformly treated substrate. The essential feature of the coating (slurry) is believed to be interconnected pores which allow ionic conductivity. The interconnected pores are believed to be formed by the interaction of the plasticizer and inorganic fibers. The major failure mode of silver zinc cells using such a separator (zinc nodules shorting adjacent plates) was investigated.

Bozek, J. M.↗
NASA NTRS1974

Shock-induced separation of adiabatic turbulent boundary layers in supersonic axially symmetric internal flow

An experimental investigation at Mach 4 of shock-induced turbulent boundary layer separation at the walls of axially symmetric flow passages is discussed, with particular emphasis placed on determining the shock strengths required for incipient separation. The shock waves were produced by interchangeable sting-mounted cones placed on the axes of the flow passages and aligned with the freestream flow. The interactions under study simulate those encountered in axially symmetric engine inlets of supersonic aircraft. Knowledges of the shock strengths required for boundary layer separation in inlets is important since for shocks of somewhat greater strength rather drastic alterations in the inlet flow field may occur.

Page, R. J.↗
NASA NTRS1974

Solutions for laminar boundary layers with separation and reattachment

Numerical solutions of the laminar, incompressible boundary-layer equations are presented for flows involving separation and reattachment. Regular solutions are obtained with an inverse approach in which either the displacement thickness or the skin friction is specified, and the pressure is deduced from the solution. A stream function/vorticity formulation of the boundary-layer equations is used to eliminate the unknown pressure. Solutions of the resulting finite-difference equations, in which the flow direction is taken into account, are obtained by a successive column iteration scheme. Results are compared with Klineberg and Steger's (1974) separated boundary-layer calculations, and with Briley's (1971) solution of the Navier-Stokes equations for a separated region.

Carter, J. E.↗
NASA NTRS1975

Black-and-white separations of spacecraft original film

Separation systems and a detailed procedure for the production and evaluation of separation negatives are reported. It is shown that these separation negatives have excellent stability, and meet archival storage requirements.

Perry, L.↗
NASA NTRS1975

Aerodynamic results of a separation effects test conducted in the AEDC 40 by 40 inch tunnel A facility on the Rockwell International launch configuration 3 (model-OTS) integrated vehicle (IA13), volume 1

Experimental aerodynamic investigations were conducted from July 5 through July 17, 1973, on a 0.01 scale model. The AEDC captive trajectory system was utilized in conjunction with the tunnel primary sector to obtain grid-type data for external tank abort from the orbiter, and for nominal separation of one solid rocket booster from the orbiter-tank combination. Booster separation was investigated with and without separation motors plume simulation. The plumes were generated by eight M sub j = 2.15 nozzles using a 1500 psia cold air supply. Free stream data were obtained for all models (orbiter, tank, orbiter-tank, and right-hand booster) to provide baselines for evaluation of proximity effects.

Campbell, J. H., II↗
NASA NTRS1975

The simulation of turbulent boundary layer separation on multi-element infinite swept wings

An improved method of simulating the effect of flow separation on potential flow over two-dimensional and infinite swept multi-element wings was developed. Two types of flow separation are considered: at the wing trailing edge, and at the cove region between the main wing and the flap. Potential flow is assumed outside the boundary layer and the separated wake. A previously obtained computer program (VIP) is modified by matching the outflow distribution for the potential flow such that the potential flow part of the real flow is duplicated and the results agree with the experimental observations. Results are given for the NACA 2412 airfoil. Iterative drag calculations are presented.

Dvorak, F. A.↗
NASA NTRS1974

Statistical separability of agricultural cover types in subsets of one to twelve spectral channels

The purpose of this study was to determine the statistical separability of multispectral measurements from agricultural cover types: corn, soybeans, green forage (hay and pasture) and forest, in one to twelve spectral channels. Multispectral scanner data in twelve spectral channels in the wavelength range 0.4 to 11.7 microns, acquired for three flightlines were analysed by applying automatic pattern recognition techniques. The same analysis was performed for the data acquired a month later over the same three flightlines to investigate the effect of time on statistical separability of agricultural cover types. In the subsets of one to six spectral channels, the combination of wavelength regions (where V, N, M and T denote the visible, near infrared, middle infrared and thermal infrared wavelength regions, respectively): V, V M, V N M, V N M T, V V N M T, V V N M M T, respectively, were found to be the best choices for getting good overall statistical separability of the agricultural cover types for the data acquired.

Kumar, R.↗
NASA NTRS1975

Technology and methodology of separating two similar size aerospace vehicles within the atmosphere

During the past 10 years, the parallel separation, within the atmosphere, of two similar size aerospace vehicles has been investigated in technical areas such as static and dynamic stability, rocket exhaust plume interference, aerodynamic control, loads, and dynamic simulation. Advanced experimental and analysis techniques have been developed to analyze this problem. Results are presented which summarize some of this work. The effects of various parameters on the separation maneuver are illustrated using results from early and current space shuttle configurations. The technology and methodology that have been developed have helped verify the feasibility of separating similar size aerospace vehicles.

Decker, J. P.↗
NASA NTRS1975

Solutions for incompressible separated boundary layers including viscous-inviscid interaction

Numerical solutions are presented for the laminar and turbulent boundary-layer equations for incompressible flows with separation and reattachment. The separation angularity is avoided by using an inverse technique in which the displacement thickness is prescribed and the pressure is deduced from the resulting solution. The turbulent results appear qualitatively correct despite the use of a two-layer eddy-viscosity model which is generally assumed appropriate only for mild-pressure-gradient flows. A new viscous-inviscid interaction technique is presented in which the inviscid flow is solved inversely by prescribing the pressure from the boundary-layer solution and deducing the new displacement thickness from the solution of a Cauchy integral. Calculations are presented using this interaction procedure for a laminar flow in which separation and reattachment occur on a solid surface.

Carter, J. E.↗
NASA NTRS1975

Lip noise generated by flow separation from nozzle surfaces

The results of a series of experiments, performed to investigate flow separation and classic lip noise and to aid in understanding aeroacoustic noise generation are presented. Several types of nozzle-lip configurations were used to study the high frequency noise generated by small regions of flow separation at the nozzle lip. These included coaxial nozzles, and circular and slot nozzles with splitter plates. The jet flow velocity was varied and far field noise was measured for all nozzle-lip geometries (coaxial and splitter plate). The effect of a velocity difference across the lip of the coaxial nozzle and the splitter plate on the far field noise was also measured. Finally, an effort was made to find means to reduce the high frequency noise caused by flow separation at the lip.

Olsen, W.↗
NASA NTRS1976

Results of an experimental investigation to determine separation characteristics for the Orbiter/747 using a 0.0125-scale model (48-0 AX1318I-1 747) in the Ames Research Center 14-foot wind tunnel (CA23B)

Aerodynamic separation data obtained from a wind tunnel test of an 0.0125-scale SSV Orbiter model of a VC70-000002 Configuration and a 0.0125-scale 747 model was presented. Separation data was obtained at a Mach number of 0.6 and three incidence angles of 4, 6, and 8 degrees. The orbiter angle of attack was varied from 0 to 14 degrees. Longitudinal, lateral and normal separation increments were obtained for fixed 747 angles of attack of 0, 2, and 4 degrees while varying the orbiter angle of attack. Control surface settings on the 747 carrier included rudder deflections of 0 and 10 degrees and horizontal stabilizer deflections of -1 and +5 degrees.

Esparza, V.↗
NASA NTRS1976

Separation of granulocytes from whole blood by leukoadhesion, phase 1

Capillary glass tubes are investigated for the separation and retrieval of large quantities of viable granulocytes and monocytes from whole blood on a continuous basis from a single donor. This effort represented the feasibility demonstration of a three phase program for development of a capillary tube cell separation device. The activity included the analysis and parametric laboratory testing with subscale models required to design a prototype device. Capillary tubes 40 cm long with a nominal 0.030 cm internal diameter yielded the highest total process efficiency. Recovery efficiencies as high as 89% of the adhering cell population were obtained. Granulocyte phagocytosis of latex particles indicated approximately 90% viability. Monocytes recovered from the separation column retained their capability to stimulate human bone marrow colony growth, as demonstrated in an in vitro cell culture assay.

Source record↗
NASA NTRS1976

Stage separation study of Nike-Black Brant V Sounding Rocket System

A new Sounding Rocket System has been developed. It consists of a Nike Booster and a Black Brant V Sustainer with slanted fins which extend beyond its nozzle exit plane. A cursory look was taken at different factors which must be considered when studying a passive separation system. That is, one separation system without mechanical constraints in the axial direction and which will allow separation due to drag differential accelerations between the Booster and the Sustainer. The equations of motion were derived for rigid body motions and exact solutions were obtained. The analysis developed could be applied to any other staging problem of a Sounding Rocket System.

Ferragut, N. J.↗
NASA NTRS1976

Three-dimensional boundary layers approaching separation

The theory of semi-similar solutions of the laminar boundary layer equations is applied to several flows in which the boundary layer approaches a three-dimensional separation line. The solutions obtained are used to deduce the nature of three-dimensional separation. It is shown that in these cases separation is of the "ordinary" type. A solution is also presented for a case in which a vortex is embedded within the three-dimensional boundary layer.

Williams, J. C., III↗
NASA NTRS1977

Quick look analysis of an emergency separation for ALT captive-inert flight 1

Emergency separation capability for the landing configuration of ALT Captive Inert Flight Number One was investigated. The quick look analysis confirms emergency separation capability under nominal conditions for the ALT landing configuration. The recommended emergency separation procedure under those conditions is not applicable to all ALT configurations.

Glenn, G. M.↗
NASA NTRS1977

Boundary layer separation on isolated boattail nozzles

The phenomenon of separated flow on a series of circular-arc afterbodies was investigated using the Langley 16-foot transonic tunnel at free-stream Mach numbers from 0.40 to 0.95 at 0 deg angle of attack. Both high-pressure air and solid circular cylinders with a diameter equal to the nozzle exit diameter were used to simulate jet exhausts. A detailed data base of boundary layer separation locations was obtained using oil-flow techniques. The results indicate that boundary layer separation is most extensive on steep boattails at high Mach numbers.

Abeyounis, W. K.↗
NASA NTRS1977

Isotope separation using metallic vapor lasers

The isotope U235 is separated from a gasified isotope mixture of U235 and U238 by selectively exciting the former from the ground state utilizing resonant absorption of radiation from precisely tuned lasers. The excited isotope is then selectively ionized by electron bombardment. It then is separated from the remaining isotope mixture by electromagnetic separation.

Russell, G. R.↗
NASA NTRS1977

Investigation of supersonic turbulent boundary-layer separation on a compression ramp by an integral method

An investigation was made to determine the feasibility of using a boundary layer integral method to study the separation of a turbulent boundary layer on a two dimensional ramp at supersonic speeds. The numerical calculations were made for a free stream Mach number of 3, a Reynolds number of 10 million, and over a ramp angle range from 0 deg to 30 deg. For ramp angles where no flow separation was indicated, theoretical calculations were in reasonable agreement with experimental data except for a somewhat belated rise in pressure. For larger ramp angles, where separation was present, the investigation produced results that were not in agreement with experiment or with results calculated by time dependent Navier-Stokes methods. This apparently was true because no provision had been made for a proper shock boundary layer interaction where strong normal pressure gradients are induced within the boundary layer under the shock independent of surface curvature effects.

Patel, D. K.↗