Search NASA⌕ Search

SEARCH · Search NASA

Results for “hydrogen analysis”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

Analysis of a 100-W Regenerative Fuel Cell Demonstration

A 100-W regenerative fuel cell (RFC) demonstration was successfully completed at the NASA Glenn Research Center on December 11, 2014. This effort was funded by Advanced Space Power Systems milestone and represented the first demonstration of passive laboratory-scale stacks arranged as an RFC, consisting of a non-flow-through fuel cell and a static-feed electrolyzer. Once developed, these stacks present the potential to minimize system mass, volume, and parasitic power in comparison to existing terrestrial electrochemical systems and nonnuclear power generation options. Testing involved the fuel cell powering a simulated load then recycling fuel cell product water by subsequently electrolyzing it to regenerate hydrogen and oxygen gases for fuel cell operations. A total of five cycles were completed over a 2-week period, yielding cell voltage data for stack performance and quality measures for regenerated reactants. Overall, round-trip efficiency was calculated to be 47.4 percent. Gas crossover was observed in electrolyzer gas products, as residual gas analysis showed 1.1 percent hydrogen in oxygen and 0.4 percent oxygen in hydrogen. Fuel cell product water was determined to be more acidic and conductive and have a higher fluoride content when compared to deionized water.

fuel cell↗
NASA NTRS1990

On the use of external burning to reduce aerospace vehicle transonic drag

The external combustion of hydrogen to reduce the transonic drag of aerospace vehicles is currently being investigated. A preliminary analysis based on a constant pressure control volume is discussed. Results indicate that the specific impulse of the external burning process rivals that of a turbojet and depends on the severity of the initial base drag as well as on the Mach flight number and the equivalence ratio. A test program was conducted to investigate hydrogen-air flame stability at the conditions of interest and to demonstrate drag reduction on a simple expansion ramp. Initial test results are presented and compared with the control-volume analysis. The expansion ramp surface pressure coefficient showed little variation with fuel pressure and altitude, in disagreement with the analysis. Flame stability results were encouraging and indicate that stable combustion is possible over an adequate range of conditions. Facility interference and chemical kinetics phenomena that make interpretation of subscale ground test data difficult are discussed.

Trefny, Charles J.↗
NASA NTRS1990

On the use of external burning to reduce aerospace vehicle transonic drag

The external combustion of hydrogen to reduce the transonic drag of aerospace vehicles is currently being investigated. A preliminary analysis based on a constant pressure control volume is discussed. Results indicate that the specific impulse of the external burning process rivals that of a turbojet and depends on the severity of the initial base drag as well as on the Mach flight number and the equivalence ratio. A test program was conducted to investigate hydrogen-air flame stability at the conditions of interest and to demonstrate drag reduction on a simple expansion ramp. Initial test results are presented and compared with the control-volume analysis. The expansion ramp surface pressure coefficient showed little variation with fuel pressure and altitude, in disagreement with the analysis. Flame stability results were encouraging and indicate that stable combustion is possible over an adequate range of conditions. Facility interference and chemical kinetics phenomena that make interpretation of subscale ground test data difficult are discussed.

Trefny, Charles J.↗
NASA NTRS1985

Support systems design and analysis

The integration of Kennedy Space Center (KSC) ground support systems with the new launch processing system and new launch vehicle provided KSC with a unique challenge in system design and analysis for the Space Transportation System. Approximately 70 support systems are controlled and monitored by the launch processing system. Typical systems are main propulsion oxygen and hydrogen loading systems, environmental control life support system, hydraulics, etc. An End-to-End concept of documentation and analysis was chosen and applied to these systems. Unique problems were resolved in the areas of software analysis, safing under emergency conditions, sampling rates, and control loop analysis. New methods of performing End-to-End reliability analyses were implemented. The systems design approach selected and the resolution of major problem areas are discussed.

Ferguson, R. M.↗
NASA NTRS1977

The galactic distribution (in radius and Z) of interstellar molecular hydrogen

Observations of the galactic longitude and latitude distributions of lambda = 2.6 mm CO emission are presented. Analysis of these spectral-line data yields the large-scale distribution of molecular clouds in the galactic disk and their z-distribution out of the disk. Strong maxima in the number of molecular clouds occur in the galactic nucleus and at galactic radii 4 to 8 kpc. The peak at 4 to 8 kpc correlates well with a region of enhanced 100-MeV gamma-ray emissivity. This correlation strongly supports the conclusion that the gamma-rays are produced as a result of cosmic ray interactions in molecular H2 clouds rather than in H(I). The width of the cloud layer perpendicular to the galactic plane between half-density points is 105 plus or minus 15 pc near the 5.5-kpc peak. The total mass of molecular gas in the interior of the galaxy exceeds that of atomic hydrogen and is 30 to the 9th power solar mass based on these observations.

Scoville, N. Z.↗
NASA NTRS1973

Materials interactions between the thermoelectric converter and the 5kwe reactor system

The integration of a compact thermoelectric converter with a 5-kwe reactor system is described. Material interaction uncertainties study is also presented. This includes degradation of the required austenitic - refractory metal transition joint during operation at high temperatures; loss of corrosion resistance; embrittlement by the presence of hydrogen; and loss of design margin by transport of interstitial elements. Analysis and limited experimental evidence indicate that these potential materials interactions can be adequately controlled. Group 5-2 refractory metals can be utilized without unacceptable adverse effect on system reliability.

Ferry, P. B.↗
NASA NTRS1978

Thermostructural analysis of a scramjet fuel-injection strut

Results of a thermal/structural design analysis study of a fuel injection strut for an airframe integrated hydrogen cooled scramjet are presented. It is indicated that a feasible thermal/structural concept has been identified for the static load conditions and that thermal stresses dominate the response. It is suggested that the response of the concept to dynamic loads be investigated.

Wieting, A. R.↗
NASA NTRS1979

Energy: An annotated selected bibliography

This updated bibliography contains approximately 7,000 selected references on energy and energy related topics from bibliographic and other data sources from June 1977. Under each subject heading the entries are arranged by the data, with the latest works first. Subject headings include: resources supply/demand, and forecasting; policy, legislation, and regulation; environment; consumption, conservation, and economics; analysis, systems, and modeling, and information sources and documentation. Fossil fuels, hydrogen and other fuels, liquid/solid wastes and biomass, waste heat utilization, and nuclear power sources are also included.

Blow, S. J.↗
NASA NTRS1982

The 1981 Goddard Space Flight Center Battery Workshop

Results of testing, analysis, and development of lithium, nickel-cadmium, and nickel-hydrogen batteries are reported. Focus is on the improvement of power systems in the areas of high capacity, high energy density, and long cycle and storage life. Applications of these batteries as spacecraft power supplies are discussed. Those spacecraft include deepspace probes, spacecraft in geostationary orbit, and large space systems in low-Earth orbit.

Halpert, G.↗
NASA NTRS1992

Ceramic matrix composites for rocket engine turbine applications

A program to establish the potential for introducing fiber reinforced ceramic matrix composites (FRCMC) in future rocket engine turbopumps was instituted in 1987. A brief summary of the overall program (both contract and in-house research) is presented. Tests at NASA Lewis include thermal upshocks in a hydrogen/oxygen test rig capable of generating heating rates up to 2500 C/sec. Post thermal upshock exposure evaluation includes the measurement of residual strength and failure analysis. Test results for monolithic ceramics and several FRCMC are presented. Hydrogen compatibility was assessed by isothermal exposure of monolithic ceramics in high temperature gaseous hydrogen plus water vapor.

Herbell, Thomas P.↗
NASA NTRS2005

Warm Molecular Gas Traced with CO J = 7 --> 6 in the Galaxy's Central 2 Parsecs: Dynamical Heating of the Circumnuclear Disks

We present an 11" resolution map of the central 2 pc of the Galaxy in the CO J = 7 --> 6 rotational transition. The CO emission shows rotation about Sgr A* but also evidence for noncircular turbulent motion and a clumpy morphology. We combine our data set with available CO measurements to model the physical conditions in the disk. We find that the molecular gas in the region is both warm and dense, with T approx. 200-300 K and n(sub H2) approx. (5-7) x 10(exp 4) cm(exp -3). The mass of warm molecular gas we measure in the central 2 pc is at least 2000 M(solar), about 20 times the UV-excited atomic gas mass, ruling out a UV heating scenario for the molecular material. We compare the available spectral tracers with theoretical models and conclude that molecular gas is heated with magnetohydrodynamic shocks with v approx. 10-20 km s(exp -1) and B approx. 0.3- 0.5 mG. Using the conditions derived with the CO analysis, we include the other important coolants, neutral oxygen and molecular hydrogen, to estimate the total cooling budget of the molecular material. We derive a mass-to-luminosity ratio of approx. 2-3 M(solar)(L(solar)exp -1), which is consistent with the total power dissipated via turbulent decay in 0.1 pc cells with v(sub rms) approx. 15 kilometers per second. These size and velocity scales are comparable to the observed clumping scale and the velocity dispersion. At this rate, the material near Sgr A* is dissipating its orbital energy on an orbital timescale and cannot last for more than a few orbits. Our conclusions support a scenario in which the features near Sgr A* such as the circumnuclear disk and northern arm are generated by infalling clouds with low specific angular momentum.

galatic nuclei↗
NASA NTRS2019

Lyman-Alpha Imaging Polarimetry with the CLASP2 Sounding Rocket Mission

Ultraviolet polarimetry offers a unique opportunity to explore the upper solar chromosphere and the transition region (TR) to the million-degree corona. These outer atmospheric regions play a key role in the transfer of mass and energy from the solar photosphere to the corona. With a sounding rocket experiment called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), in September 2015 we succeeded in obtaining the first measurement of the linear polarization produced by scattering processes in the hydrogen Lyman-alpha line of the solar disk radiation. The analysis and interpretation of such spectro-polarimetric observation allowed us to obtain information on the geometrical complexity of the corrugated surface that delineates the TR, as well as on the magnetic field strength via the Hanle effect. At the same time, the CLASP slit-jaw (SJ) optics system, which is a Lyman-alpha filter imager characterized by a FWHM (Full Width Half Maximum) equals 7 nanometers, allowed us to obtain broad-band Stokes-I and Q/I images over a large field of view. The obtained broad-band Q/I images are dominated by the scattering polarization signals of the Lyman-alpha wings, and not by the much weaker line-center signals where the Hanle effect operates. On April 11, 2019, we performed another sounding rocket experiment, called the Chromospheric LAyer Spectro-Polarimeter (CLASP2). We used the same instrument after significant modifications in order to obtain spectro-polarimetric observations of a plage and a quiet region in the Mg II h & k lines. At the same time, the CLASP2 SJ optics system allowed us to obtain broad-band Q/I and U/I images around the Lyman-alpha wavelength, in addition to the well- known SJ intensity images.

Kano, Ryouhei↗
NASA NTRS1976

The galactic distribution (in radius and Z) of interstellar molecular hydrogen

Observations of the galactic longitude and latitude distributions of gamma = 2.6 mm CO emission are presented. Analysis of this spectral line data yields the large scale distribution of molecular clouds in the galactic disk and their z-distribution out of the disk. Strong maxima in the number of molecular clouds occur in the galactic nucleus and at galactic radii 4-8 kpc. The peak at 4-8 kpc correlates well with a region of enhanced 100 Mev gamma ray emissivity. This correlation strongly supports the conclusion that the gamma rays are produced as a result of cosmic ray interactions in molecular H2 clouds rather than HI. One important implication of this is that the interstellar magnetic field lines to which cosmic rays are confined must therefore not be excluded from these dense clouds. The width of the cloud layer perpendicular to galactic plane between half density points is 105 + or - 15 pc near the 5.5 kpc peak. The total mass of molecular gas in the interior of the galaxy exceeds that of atomic hydrogen.

Scoville, N. Z.↗
NASA NTRS1978

Design and analysis of a scramjet engine

Design concepts defined for the cooled-structures assembly of a hydrogen fueled, regeneratively cooled, airframe-integrated Scramjet engine are considered. Engine subsystems, in particular, the fuel subsystem associated with the operating engine are included along with the engine mounting and the interfacing with the airplane. The engine structure and thermal protection system, including the fuel injection struts are emphasized.

Buchmann, O. A.↗
NASA NTRS2000

Thermographic Analysis of Composite Cobonds on the X-33

During the manufacture of the X-33 liquid hydrogen (LH2) Tank 2, a total of thirty-six reinforcing caps were inspected thermographically. The cured reinforcing sheets of graphite/epoxy were bonded to the tank using a wet cobond process with vacuum bagging and low temperature curing. A foam filler material wedge separated the reinforcing caps from the outer skin of the tank. Manufacturing difficulties caused by a combination of the size of the reinforcing caps and their complex geometry lead to a potential for trapping air in the bond line. An inspection process was desired to ensure that the bond line was free of voids before it had cured so that measures could be taken to rub out the entrapped air or remove the cap and perform additional surface matching. Infrared thermography was used to perform the precure "wet bond" inspection as well as to document the final "cured" condition of the caps. The thermal map of the bond line was acquired by heating the cap with either a flash lamp or a set of high intensity quartz lamps and then viewing it during cool down. The inspections were performed through the vacuum bag and voids were characterized by localized hot spots. In order to ensure that the cap had bonded to the tank properly, a post cure "flash heating" thermographic investigation was performed with the vacuum bag removed. Any regions that had opened up after the preliminary inspection or that were hidden during the bagging operation were marked and filled by drilling small holes in the cap and injecting resin. This process was repeated until all critical sized voids were filled.

Russell, Samuel S.↗
NASA NTRS2001

Thermographic Analysis of Composite Cobonds on the X-33

During the manufacture of the X-33 liquid hydrogen (LH2) Tank 2, a total of 36 reinforcing caps were inspected thermographically. The cured reinforcing sheets of graphite/epoxy were bonded to the tank using a wet cobond process with vacuum bagging and low temperature curing. A foam filler material wedge separated the reinforcing caps from the outer skin of the tank. Manufacturing difficulties caused by a combination of the size of the reinforcing caps and their complex geometry lead to a potential for trapping air in the bond line. An inspection process was desired to ensure that the bond line was free of voids before it had cured so that measures could be taken to rub out the entrapped air or remove the cap and perform additional surface matching. Infrared thermography was used to perform the procure 'wet bond' inspection as well a to document the final 'cured' condition of the caps. The thermal map of the bond line was acquired by heating the cap with either a flash lamp or a set of high intensity quartz lamps and then viewing it during cool down. The inspections were performed through the vacuum bag and voids were characterized by localized hot spots. In order to ensure that the cap had bonded to the tank properly, a post cure 'flash heating' thermographic investigation was performed with the vacuum bag removed. Any regions that had opened up after the preliminary inspection or that were hidden during the bagging operation were marked and filled by drilling small holes in the cap and injecting resin. This process was repeated until all critical sized voids were filled.

Russell, S. S.↗
NASA NTRS2012

Compound-Specific Isotopic Analysis of Meteoritic Amino Acids as a Tool for Evaluating Potential Formation Pathways

Measurements of stable hydrogen, carbon, and nitrogen isotopic ratios (delta D, delta C-13, delta N-15) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may point towards the most likely of these proposed pathways. The technique of gas chromatography coupled with mass spectrometry and isotope ratio mass spectrometry provides compound-specific structural and isotopic information from a single splitless injection, enhancing the amount of information gained from small amounts of precious samples such as carbonaceous chondrites. We have applied this technique to measure the compound-specific C, N, and H isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites. We are using these measurements to evaluate predictions of expected isotopic enrichments from potential formation pathways and environments, leading to a better understanding of the origin of these compounds.

Elsila, Jamie E.↗