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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

Sodium storage and injection system

A sodium storage and injection system for delivering atomized liquid sodium to a chemical reactor employed in the production of solar grade silicon is disclosed. The system is adapted to accommodate start-up, shut-down, normal and emergency operations, and is characterized by (1) a jacketed injection nozzle adapted to atomize liquefied sodium and (2) a supply circuit connected to the nozzle for delivering the liquefied sodium. The supply circuit is comprised of a plurality of replaceable sodium containment vessels, a pump interposed between the vessels and the nozzle, and a pressurizing circuit including a source of inert gas connected with the vessels for maintaining the sodium under pressure.

Keeton, A. R.↗
NASA NTRS1980

Time dependent plasma injection by Io

A two parameter model of time-dependent, flux-tube interchange diffusion is fit to the Voyager 1 plasma data obtained in the Io plasma disk. The interpretation of the parameters required to achieve the fit is that plasma injection increased suddenly and substantially (by more than an order of magnitude) at some time prior to the arrival of Voyager 1 (between 1 and 100 days prior). The injection rate was about 2 x 10 to the (29 plus or minus 1) power ion/sec. At this rate, the centrifugally driven interchange instability dominated outward diffusion, causing the outward diffusion rate to be about a factor of 50 greater than the inward diffusion rate. The material diffusing inward had time to cool by radiation, possibly accounting for the observed temperature drop inside the orbit of Io.

Richardson, J. D.↗
NASA NTRS1980

A new planar injection-gated bulk switching device based upon deep impurity trapping

Under the proper conditions, double-injection (DI) diodes with partially compensated deep impurities will exhibit 'S'-type switching characteristics similar to conventional silicon-controlled rectifiers (SCR's). A practical injection-gating scheme has been achieved for the first time in a planar configuration to control the switching behavior of these devices, marked by extreme sensitivity of the gate over a range of switching voltages. An experiment to demonstrate the feasibility of these devices for practical application is described. Finally, a phenomenological explanation is presented for the gate-controlled switching of these devices.

Kapoor, A. K.↗
NASA NTRS1980

Large optical cavity AlGaAs injection lasers with multiple active regions

A new type of AlGaAs injection laser is presented whose basic structure consists of alternating p- and n-type layers of GaAs and Al(x)Ga(1-x), with the GaAs layers serving as the active regions of the device. The electrical mode of operation is found to be that of a bistable device (SCR) and not of a simple pn junction. Optically, the device oscillates in a 'supermode' made up of a coherent superposition of single waveguide modes. Possible applications include pulsed mode operation of injection lasers and power combining of the output of many individual lasers.

Katz, J.↗
NASA NTRS1980

Initial assessment of the effects of energetic ion injections in the magnetosphere due to the transport of satellite power system components from low earth orbit to geosynchronous earth orbit

Potentially serious environmental effects exist when cargo orbital transfer vehicle (COTV) ion propulsion is used on the scale proposed in the preliminary definition studies of the Satellite Power System. These effects of the large scale injections of ion propulsion exhaust in the plasmasphere and in the outer magnetosphere were shown to be highly model dependent with major differences existing in the predicted effects of two models, the ion cloud model and the ion sheath model. The expected total number density deposition of the propellant Ar(+) in the plasmasphere, the energy spectra of the deposited Ar(+) and time dependent behavior of the Ar(+) injected into the plasmasphere by a fleet of COTV vehicles differ drastically between the two models. The ion sheath model was demonstrated to be applicable to the proposed Ar(+) beam physics if the beam was divergent and turbulent whereas the ion cloud model was not a realistic approximation for such a beam because the "frozen-field" assumption on which it is based is not valid.

Curtis, S. A.↗
NASA NTRS1981

Analysis for predicting adiabatic wall temperatures with single hole coolant injection into a low speed crossflow

Assuming the local adiabatic wall temperature equals the local total temperature in a low speed coolant mixing layer, integral conservation equations with and without the boundary layer effects are formulated for the mixing layer downstream of a single coolant injection hole oriented at a 30 degree angle to the crossflow. These equations are solved numerically to determine the center line local adiabatic wall temperature and the effective coolant coverage area. Comparison of the numerical results with an existing film cooling experiment indicates that the present analysis permits a simplified but reasonably accurate prediction of the centerline effectiveness and coolant coverage area downstream of a single hole crossflow streamwise injection at 30 degree inclination angle.

Wang, C. R.↗
NASA NTRS1980

Transverse injection of a particle-laden liquid jet in supersonic flow: A three-phase flow

The results of a two part study of the behavior of particle laden liquid jets injected into air are presented. Water was used as the liquid carrier and either 1-37 or 13-44 microns diam. spherical glass beads with a specific gravity of 2.8-3.0 as the particles. The observations were mainly photographic. The breakup of jets injected into still air was investigated as a function of particle loading, and the results were compared to the pure liquid jet case. The jets were found to be more stable with particles present. The length to breakup was increased, and the formation of satellite droplets was suppressed. The penetration and breakup of transverse jets in a Mach 3.0 air stream was studied. The general breakup mechanism of wave formation was found to be the same as for the all liquid case. Significant separation of the phases was observed, and the penetration of the liquid phase was reduced compared to all liquid cases at the same value of the jet to free stream momentum flux ratio.

Schetz, J. A.↗
NASA NTRS1980

Off-design analysis of a gas turbine powerplant augmented by steam injection using various fuels

Results are compared using coal derived low and intermediate heating valve fuel gases and a conventional distillate. The results indicate that steam injection provides substantial increases in both power and efficiency within the available compressor surge margin. The results also indicate that these performance gains are relatively insensitive as to the type of fuel. Also, in a cogeneration application, steam injection could provide some degree of flexibility by varying the split between power and process steam.

Stochl, R. J.↗
NASA NTRS1981

Stagnation region gas film cooling: Spanwise angled injection from multiple rows of holes

The stagnation region of a cylinder in a cross flow was used in experiments conducted with both a single row and multiple rows of spanwise angled (25 deg) coolant holes for a range of the coolant blowing ratio with a freestream to wall temperature ratio approximately equal to 1.7 and R(eD) = 90,000. Data from local heat flux measurements are presented for injection from a single row located at 5 deg, 22.9 deg, 40.8 deg, 58.7 deg from stagnation using a hole spacing ratio of S/d(o) = 5 and 10. Three multiple row configurations were also investigated. Data are presented for a uniform blowing distribution and for a nonuniform blowing distribution simulating a plenum supply. The data for local Stanton Number reduction demonstrated a lack of lateral spreading by the coolant jets. Heat flux levels larger than those without film cooling were observed directly behind the coolant holes as the blowing ratio exceeded a particular value. The data were spanwise averaged to illustrate the influence of injection location, blowing ratio and hole spacing. The large values of blowing ratio for the blowing distribution simulating a plenum supply resulted in heat flux levels behind the holes in excess of the values without film cooling. An increase in freestream turbulence intensity from 4.4 to 9.5 percent had a negligible effect on the film cooling performance.

Luckey, D. W.↗
NASA NTRS1981

Analysis for predicting adiabatic wall temperatures with single hole coolant injection into a low speed crossflow

Assuming the local adiabatic wall temperature equals the local total temperature in a low speed coolant mixing layer, integral conservation equations with and without the boundary layer effects are formulated for the mixing layer downstream of a single coolant injection hole oriented at a 30 degree angle to the crossflow. These equations are solved numerically to determine the center-line local adiabatic wall temperature and the effective coolant coverage area. Comparison of the numerical results with an existing film cooling experiment indicates that the present analysis permits a simplified but reasonably accurate prediction of the centerline effectiveness and coolant coverage area downstream of a single hole crossflow streamwise injection at 30-deg inclination angle.

Wang, C. R.↗
NASA NTRS1981

Fabrication of injection molded sintered alpha SiC turbine components

Fabrication of a sintered alpha silicon carbide turbine blade by injection molding is described. An extensive process variation matrix was carried out to define the optimum fabrication conditions. Variation of molding parameters had a significant impact on yield. Turbine blades were produced in a reasonable yield which met a rigid quality and dimensional specification. Application of injection molding technology to more complex components such as integral rotors is also described.

Storm, R. S.↗
NASA NTRS1980

Mass-injection rate from Io into the Io plasma torus

Theoretical arguments to the effect that both plasma and energy are supplied to the Jovian magnetosphere from primarily internal sources are presented. Two major assumptions are made: (1) that Io is the source of plasma for the Jovian magnetosphere, and that the outward flow of plasma from the torus is the means of drawing from the kinetic energy of rotation of Jupiter to drive magnetospheric phenomena; thereby obtaining a new, independent estimate of the rate of mass injection from Io into the Io plasma torus, and (2) that the solar wind supplies neither plasma nor energy to the Jovian magnetosphere in significant amounts. A lower limit to the rate of mass injection into the torus, which on the average must equal the rate of mass loss from the torus, is therefore derivable through adoption of a value for the power expended to drive the various magnetospheric phenomena.

Dessler, A. J.↗
NASA NTRS1982

Assessment of steam-injected gas turbine systems and their potential application

Results were arrived at by utilizing and expanding on information presented in the literature. The results were analyzed and compared with those for simple gas turbine and combined cycles for both utility power generation and industrial cogeneration applications. The efficiency and specific power of simple gas turbine cycles can be increased as much as 30 and 50 percent, respectively, by the injection of steam into the combustor. Steam-injected gas turbines appear to be economically competitive with both simple gas turbine and combined cycles for small, clean-fuel-fired utility power generation and industrial cogeneration applications. For large powerplants with integrated coal gasifiers, the economic advantages appear to be marginal.

Stochl, R. J.↗
NASA NTRS1980

Effects of argon ion injections in the plasmasphere

In lifting massive space power system payloads from low Earth orbit to geosynchronous Earth orbit, Cargo Orbit Transfer (COTV) using ion propulsion will inject energetic beams of argon ions into the plasmasphere. The relationship of the beam velocity to Alfven and thermal velocities as a function of radial distance in the plasmasphere is given for positions near the Earth's equatorial plane. A beam sheath loss model is used which results in a deposition of argon ions and hence energy in the plasmasphere which is much less than that in models calling for clouds or plasma instabilities to rapidly stop the beam. A comparison is given of the cumulative fractional mass loss of an ion beam injected at 1.5 R for the ion cloud and the ion beam sheath loss process. The integrated difference of these two deposition models is shown for the construction of one SPS.

Curtis, S. A.↗
NASA NTRS1982

Plasma injection events at synchronous orbit related to positive Dst

AST 6 spacecraft synchronous orbit measurements are compared with space and ground data in a study of plasma effects related to SI and SC magnetic perturbations. It is found that synchronous orbit plasma injections related to the sudden phenomena are similar to those associated with substorms, although the former occur at all local times. The synchronous orbit plasma injections are interpreted as the co-location of particle boundaries on an inward propagating front and the compression magnetic pulse associated with SI and SC events is seen as responsible for the co-location of the boundaries and their inward propagation. The positive Dst magnetic pulse plays a role similar to that of the magnetic tail reconfiguration pulse associated with substorms, and evidence is shown that positive Dst enhances magnetospheric convection independently of interplanetary magnetic field direction

Arnoldy, R. L.↗
NASA NTRS1982

Plasma injection and transport in the mid-altitude polar cusp

DE-1 hot plasma observations in the mid-altitude polar cusp have shown evidence of a significant velocity filtering phenomenon which is consistent with a latitudinally narrow region of plasma injection located at a geocentric distance of about eight earth radii (in a dipole approximation). Plasma convection from the injection region into the polar cap results in a V-shaped log E vs. observed pitch angle relation at geocentric distances near 4 earth radii. This velocity filtering effect allows the measurement of much smaller flow velocities (about 10 km/sec) than have heretofore been possible with hot plasma measurements. The flows thus determined are consistent with ionospheric flows measured nearly simultaneously by the DE-2 spacecraft, although the magnitudes of the higher altitude flows are higher by a factor of 2 or more than an approximately r to the 3/2 power dipole-field mapping would predict.

Burch, J. L.↗
NASA NTRS1983

Three-dimensional turbulent-mixing-length modeling for discrete-hole coolant injection into a crossflow

Three dimensional mixing length models of a flow field immediately downstream of coolant injection through a discrete circular hole at a 30 deg angle into a crossflow were derived from the measurements of turbulence intensity. To verify their effectiveness, the models were used to estimate the anisotropic turbulent effects in a simplified theoretical and numerical analysis to compute the velocity and temperature fields. With small coolant injection mass flow rate and constant surface temperature, numerical results of the local crossflow streamwise velocity component and surface heat transfer rate are consistent with the velocity measurement and the surface film cooling effectiveness distributions reported in previous studies.

Wang, C. R.↗
NASA NTRS1983

Pulse evolution and mode selection characteristics in a TEA-CO2 laser perturbed by injection of external radiation

A grating-tunable TEA-CO2 laser with an unstable resonator cavity, modified to allow injection of CW CO2 laser radiation at the resonant transition line by means of an intracavity NaCl window, has been used to study the coupling requirements for generation of single frequency pulses. The width and shape of the mode selection region, and the dependence of the gain-switched spike buildup time and the pulse shapes on the intensity and detuning frequency of the injected radiation are reported. Comparisons of the experimental results with previously reported mode selection behavior are discussed.

Flamant, P. H.↗