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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1983

Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

Faroque, M.↗
NASA NTRS1984

Improved Gas Seal for Electrolytic Cells

Breakage by differential thermal expansion reduced. Cells for hot electrolysis of gases improved by design that reduces vulnerability of gas seals to breakage at operating temperature of about 1000 degrees C.

Richter, R.↗
DOE OSTI2025

Predictions of Cell-to-Cell Propagation and Vent Gas Production in the Thermal Runaway of Lithium-Ion Battery Stacks

This work presents the thermal runaway propagation model LIM1TR (Lithium-ion Modeling with 1-D Thermal Runaway) as an efficient tool to predict different cell-to-cell thermal runaway propagation scenarios. Here, we explored the vent gas volume production and reaction duration highlighting the relationship between these parameters and thermal runaway propagation due to convection by the vented gases. Two metrics based on gas production rate and heating rate are utilized as good indicators of the start and end of thermal runaway. LIM1TR results are compared with and validated by experiments from the literature for single-cell and multicell array experiments of 5 Ah and 10 Ah cells. By accounting for intraparticle diffusion of reacting species in the electrodes, we were able to capture the general dynamics of thermal runaway propagation and estimate acceptable reaction durations compared with the experimental values. Simulation results further demonstrated that varying heating modes lead to distinct reaction durations, consistent with experimental observations. Vent gas volume predictions indicate the need to consider both full and partial oxidation of the electrolyte. The outcomes of this work are building blocks for further investigations of module-to-module propagation by vented gases through convective heat transfer.

25 ENERGY STORAGE↗
NASA NTRS1978

Helium glow detector experiment, MA-088

Of the two 584 A channels in the helium glow detector, channel #1 appeared to provide data with erratic count rates and undue susceptibility to dayglow and solar contamination possibly because of filter fatigue or failure. Channel #3 data appear normal and of high quality. For this reason only data from this last channel was analyzed and used for detailed comparison with theory. Reduction and fitting techniques are described, as well as applications of the data in the study of nighttime and daytime Hel 584 A emission. A hot model of the interstellar medium is presented. Topics covered in the appendix include: observations of interstellar helium with a gas absorption cell: implications for the structure of the local interstellar medium; EUV dayglow observations with a helium gas absorption cell; and EUV scattering from local interstellar helium at nonzero temperatures: implications for the derivations of interstellar medium parameters.

Bowyer, C. S.↗
DOE OSTI2024

Joint Management and Optimization of Residential Natural Gas and Electricity Distribution Networks Coupled via Fuel Cells

The interesting properties of natural gas as well as the growing electric power demand worldwide have led to increasing attention to natural-gas-based distributed generation applications in electric distribution systems. This paper goes over the interdependency between a residential natural gas network and an electric distribution network that are coupled via fuel cells. The modeling of the gas network is introduced first, and then the algorithm for gas flow study is presented. The optimal placement and sizing of fuel cell based distributed generation systems are formulated to minimize the losses in both the gas and electric distribution networks, subject to their model constraints. In addition to this, in order to capture the probabilistic nature of the optimization problem under study, the K-means clustering algorithm is applied to the gas and electricity demands to determine hourly load states and their corresponding probabilities. Furthermore, simulation studies are carried out on an integrated system consisting of the IEEE 69-bus distribution feeder and a radial 27-node natural gas network to verify the developed optimization model and the proposed method.

24 POWER TRANSMISSION AND DISTRIBUTION↗
NASA NTRS1992

Thinner, More-Efficient Oxygen-Separation Cells

Better gas-distribution plates fabricated more easily. Oxygen-separation cell redesigned to make it more efficient, smaller, lighter, and easier to manufacture. Potential applications include use as gas separators, filters, and fuel cells.

Clark, Douglas J.↗
NASA NTRS1994

Techniques for in situ collection and measurement of volatiles released during hypervelocity impact

The capability of the gas capture cell to collect particles and semivolatile species which were released during impact is examined. The proposed Comet Coma Sample Return (CCSR) payload contains a variety of instrumentation for characterizing and collecting cometary dust. In this suite of instruments the Gas Capture Cell (GCC) is unique in that it not only collects the vaporization products resulting from the dust particle impacts, but also provides chemical characterization information prior to return of the dust particles for analysis on Earth. The GCC provides near real-time characterization of the volatile species, such as low- and medium-molecular-weight organic compounds that evolve from dust particles on impact with metal targets. Instrument sensitivity is sufficient for analyzing the volatile impact products resulting from single, individual dust particles. This capability will enable characterization of near-pristine dust particles, including the CHON particles, to be performed at a level not previously possible. Its design concept, operation and performance are detailed.

Heppner, R. A.↗
NASA NTRS1980

Heat pump processes induced by laser radiation

A carbon dioxide laser system was constructed for the demonstration of heat pump processes induced by laser radiation. The system consisted of a frequency doubling stage, a gas reaction cell with its vacuum and high purity gas supply system, and provisions to measure the temperature changes by pressure, or alternatively, by density changes. The theoretical considerations for the choice of designs and components are dicussed.

Garbuny, M.↗
NASA NTRS2006

Optically Driven Deformable Mirrors

Optically driven deformable mirrors may eventually supplant electrically driven deformable mirrors in some adaptive-optics and active-optics applications. Traditionally, the mirror facets in electrically driven deformable mirrors are actuated, variously, by means of piezoelectric, electrostrictive, microelectromechanical, liquid-crystal, or thermal devices. At least one such device must be dedicated to each facet, and there must be at least one wire carrying a control or drive signal to the device. If a deformable mirror comprises many (e.g., thousands) of facets, then wiring becomes a major problem for design, and the problem is compounded in cases of piezoelectric or other actuators for which high drive voltages are required. In contrast, in optically driven mirrors, the wiring problem is eliminated. The basic principle of actuation of an optically driven deformable mirror is to use a laser beam to actuate a material. For example, a laser beam can be used to heat a material to make the material thermally expand to displace a mirror facet. In an experiment to demonstrate this principle, the actuator was a Golay cell having a diameter of approximately equal to 6 mm and a length of approximately equal to 10 mm. The beam from a laser diode was aimed at an absorber in the cell, thereby heating the gas in the cell. A mirror mounted on a 12.5-micron-thick polyethylene terephthalate diaphragm at one end of the cell became displaced as the gas expanded against the diaphragm. In one representative pair of experiments at a laser beam power of 0.23 W, the beam was mechanically chopped at frequencies of 1 and 5 Hz. The mirror exhibited corresponding oscillating displacements having amplitudes of 373 and 83 micron, respectively

Hemmati, Hamid↗
NASA NTRS2012

Miniaturized Hollow-Waveguide Gas Correlation Radiometer (GCR) for Trace Gas Detection in the Martian Atmosphere

Gas correlation radiometry (GCR) has been shown to be a sensitive and versatile method for detecting trace gases in Earth's atmosphere. Here, we present a miniaturized and simplified version of this instrument capable of mapping multiple trace gases and identifying active regions on the Mars surface. Reduction of the size and mass of the GCR instrument has been achieved by implementing a lightweight, 1 mm inner diameter hollow-core optical fiber (hollow waveguide) for the gas correlation cell. Based on a comparison with an Earth orbiting CO2 gas correlation instrument, replacement of the 10 meter mUltipass cell with hollow waveguide of equivalent pathlength reduces the cell mass from approx 150 kg to approx 0.5 kg, and reduces the volume from 1.9 m x 1.3 m x 0.86 m to a small bundle of fiber coils approximately I meter in diameter by 0.05 m in height (mass and volume reductions of >99%). This modular instrument technique can be expanded to include measurements of additional species of interest including nitrous oxide (N2O), hydrogen sulfide (H2S), methanol (CH3OH), and sulfur dioxide (SO2), as well as carbon dioxide (CO2) for a simultaneous measure of mass balance.

Wilson, Emily L.↗
DOE OSTI2025

Dusty Gas Model for Solid Oxide Fuel Cell Fuel Electrode

This model applies the Dusty Gas Model simulate multi-component species transport in SOFC (solid oxide fuel cell) anodes which considers the pressure gradient across the fuel electrode. This studyhas been verified with the analytical solution for different fuel electrode thicknesses and with literature values. The model was developed using the VoronoiFVM platform in Julia which is a built in implicit and semi implicit solver that integrates electrochemical behavior, microstructural effects, and transient analysis for accurate prediction of species transport under varying conditions.

dusty gas model (DGM)↗
NASA NTRS2002

13CO2/12CO2 isotopic ratio measurements using a difference frequency-based sensor operating at 4.35 micrometers

A portable modular gas sensor for measuring the 13C/12C isotopic ratio in CO2 with a precision of 0.8%(+/-1 sigma) was developed for volcanic gas emission studies. This sensor employed a difference frequency generation (DFG)-based spectroscopic source operating at 4.35 micrometers (approximately 2300 cm-1) in combination with a dual-chamber gas absorption cell. Direct absorption spectroscopy using this specially designed cell permitted rapid comparisons of isotopic ratios of a gas sample and a reference standard for appropriately selected CO2 absorption lines. Special attention was given to minimizing undesirable precision degrading effects, in particular temperature and pressure fluctuations.

NASA Discipline Life Sciences Technologies↗
NASA NTRS1983

Systems analysis of electricity production from coal using fuel cells

Gasifiers, heat transfer, gas stability, quench, water-gas shift reaction, reforming-methanation, other catalytic reactions, compressors and expanders, acid-gas removal, the fuel cell, and catalytic combustors are described. System pressure drops, efficiency of rotating power equipment, heat exchangers, chemical reactions, steam systems, and the fuel cell subsystems are discussed.

Fleming, D. K.↗
NASA NTRS1977

Extreme ultraviolet photometer for observations of helium in interplanetary space

A four-channel photometer sensitive to two solar EUV lines which are resonantly scattered by helium gas was developed for flight on the Apollo-Soyuz Test Project. Two channels observed the 58.4-nm line of He I and used helium gas resonant absorption cells to determine the intensities of the center and wings of that line. The other two channels observed the 30.4-nm line of He II. The instrument surveyed much of the celestial sphere during a series of slow rolling maneuvers by the Apollo spacecraft. The experiment operated properly, and usable data were obtained. Study of the distributions of flux seen, and of the ratio 58.4-nm fluxes seen with gas cells full and empty, will refine current understanding of several poorly known properties of the local interstellar medium. Study of the 30.4-nm flux distribution will refine present knowledge of the structure of the earth's plasmasphere.

Bowyer, S.↗
DOE OSTI2024

Multiport high-pressure synchrotron x-ray microscopy cell (CRADA Final Report)

The LBNL team developed a multiport cell allowing for fluid flow, with electrical contacts for sample bias, and with reference electrodes. The cell is currently installed and operating in beam-line 11.0.2 of the ALS, the Berkeley Synchrotron. The cell is closed by a membrane consisting of several stacked layers of graphene (1 to 3). The graphene membrane is supported on a 100 nm thick Si3N4 membrane covered with a 20 nm thin gold film for improved adhesion of the graphene and to ensure electrical conductivity. The Si3N4 film is perforated with a periodic array of holes 1 to 2 micrometers diameter. The cell can withhold an internal pressure (gas or liquid) of up to 10 atmospheres for in situ/operando studies using X-ray Photoelectron emission (XPS), and X-ray Absorption Spectroscopy (XAS). It is also ideal for tip-enhanced nano-Infrared Spectroscopy studies of molecules at the interface between the graphene and the liquid or gas filling the cell. Materials studied in the LBNL laboratory are in the form of nanoparticles, or thin films (few nm) deposited on the side of the graphene membrane facing the solution or gas inside the cell.

36 MATERIALS SCIENCE↗