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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Rocket effluent - Its ice nucleation activity and related properties

To investigate the possibility of inadvertent weather modification from rocket effluent, aerosol samples were collected from an instrumented aircraft subsequent to the Voyager I and II launches. The aerosol's morphology, concentration and size distribution were examined with an electron microscope. The elemental compositions of individual particles were analyzed with an X-ray energy spectrometer. Ice nucleus concentration was measured with a subfreezing thermal diffusion chamber. The particles' physical and chemical properties were related to their ice nucleation activity. A laboratory experiment on rocket propellant exhaust was conducted under controlled conditions. Both laboratory and field experimental results indicated that rocket propellant exhaust can produce active ice nuclei. Their consequences for potential inadvertant weather modification demand additional study.

Parungo, F. P.↗
NASA NTRS1980

Analysis of the measured effects of the principal exhaust effluents from solid rocket motors

The feasibility of conducting environmental chamber tests using a small rocket motor to study the physical processes which occur when the exhaust products from solid motors mix with the ambient atmosphere was investigated. Of particular interest was the interaction between hydrogen chloride, aluminum oxide, and water vapor. Several types of instruments for measuring HCl concentrations were evaluated. Under some conditions it was noted that acid aerosols were formed in the ground cloud. These droplets condensed on Al2O3 nuclei and were associated with the rocket exhaust cooling during the period of plume rise to stabilization. Outdoor firings of the solid rocket motors of a 6.4 percent scaled model of the space shuttle were monitored to study the interaction of the exhaust effluents with vegetation downwind of the test site. Data concerning aluminum oxide particles produced by solid rocket motors were evaluated.

Dawbarn, R.↗
NASA NTRS1981

Synergistic erosion/corrosion of superalloys in PFB coal combustor effluent

Two Ni-based superalloys were exposed to the high velocity effluent of a pressurized fluidized bed coal combustor. Targets were 15 cm diameter rotors operating at 40,000 rpm and small flat plate specimens. Above an erosion rate threshold, the targets were eroded to bare metal. The presence of accelerated oxidation at lower erosion rates suggests erosion/corrosion synergism. Various mechanisms which may contribute to the observed oxide growth enhancement include erosive removal of protective oxide layers, oxide and subsurface cracking, and chemical interaction with sulfur in the gas and deposits through damaged surface layers.

Benford, S. M.↗
NASA NTRS1980

Synergistic erosion/corrosion of superalloys in PFB coal combustor effluent

Two Ni-based superalloys were exposed to the high velocity effluent of a pressurized fluidized bed coal combustor (PFBC). Targets were 15-cm diameter rotors operating at 40,000 rpm and small flat plate specimens. Above an erosion rate threshold (approximately 10 microns/hr), the targets were eroded to bare metal. The presence of accelerated oxidation at lower erosion rates suggests erosion/corrosion synergism. Various mechanisms which may contribute to the observed oxide growth enhancement include erosive removal of protective oxide layers, oxide and subsurface cracking, and chemical interaction with sulfur in the gas and deposits through damaged surface layers.

Benford, S. M.↗
NASA NTRS1980

Overview of HLLV effluents in stratosphere and above

The injection of large quantities of rocket exhaust effluent into the upper atmosphere by the heavy lift launch vehicle (HLLV) of the solar power satellite system is discussed. The exhaust products considered are CO, CO2, H2O, H2, and NO. The effects on the composition of the atmosphere at different altitudes are estimated.

Brubaker, K. L.↗
NASA NTRS1985

Exhaust Effluent Diffusion Model

Rocket Exhaust Effluent Diffusion Model (REEDM) predicts concentrations, dosages, and depositions downwind from normal and abnormal launches of rocket vehicles at NASA's Kennedy Space Center. REEDM written in FORTRAN IV for interactive execution.

Bjorklund, J. R.↗
NASA NTRS1990

Optical properties of marine stratocumulus clouds modified by ship track effluents

Results are presented from multispectral radiation measurements made within a marine stratocumulus cloud layer modified by ship-track effluents. The measurements showed that, compared with nearby noncontaminated clouds not affected by pollution, the upwelling intensity field of the modified stratocumulus clouds increased at a nonabsorbing wavelength in the visible region and decreased in the NIR, where absorption by liquid water is significant. The observations are consistent with an increased optical thickness, a reduced effective radius of the cloud droplets, and a reduced absorption in the contaminated cloud layer compared to a noncontaminated cloud.

King, Michael D.↗
NASA NTRS2005

Control of Effluent Gases from Solid Waste Processing using Impregnated Carbon Nanotubes

One of the major problems associated with solid waste processing technologies is effluent contaminants that are released in gaseous forms from the processes. This is a concern in both biological as well as physicochemical solid waste processing. Carbon dioxide (CO2), the major gas released, does not present a serious problem and there are currently in place a number of flight-qualified technologies for CO2 removal. However, a number of other gases, in particular NOx, SO2, NH3, and various hydrocarbons (e.g. CH4) do present health hazards to the crew members in space habitats. In the present configuration of solid waste processing in the International Space Station (ISS), some of these gases are removed by the Trace Contaminant Control System (TCCS), demands a major resupply. Reduction of the resupply can be effective by using catalyst impregnated carbon nanotubes. For example, NO decomposition to N2 and O2 is thermodynamically favored. Data showing decomposition of NO on metal impregnated carbon nanotubes is presented. Comparisons are made of the existing TCCS systems with the carbon nanotube based technology for removing NOx based on mass/energy penalties.

Li, Jing↗
NASA NTRS2005

Control of Effluent Gases from Solid Waste Processing Using Carbon Nanotubes

One of the major problems associated with solid waste processing technologies is the release of effluent gases and contaminants that are in gaseous formed from the processes. A number of other gases, in particular NO(x), SO2, NH3, Hydrocarbons (e.g. CH4) do present hazards to the crew in space habitats. Reduction of mass, power, volume and resupply can be achieved by using catalyst impregnated carbon nanotubes as compared to other catalytic systems. The development and characterization of an innovative approach for the control and elimination of gaseous toxins using single walled carbon nanotubes (SWNTs) promise superior performance over conventional approaches. This is due to the ability to direct the selective uptake of gaseous species based on their controllable pore size, high adsorptive capacity and the effectiveness of carbon nanotubes as catalyst supports for gaseous conversion. For example, SWNTs have high adsorptive capacity for NO and the adsorbed NO can be decomposed to N2 and O2 . Experimental results showing the decomposition of NO on metal impregnated carbon nanotubes is presented. Equivalent System Mass (ESM) comparisons are made of the existing TCCS systems with the carbon nanotube technology for removing NO(x). The potential for methane decomposition using carbon nanotubes catalysts is also discussed.

Fisher, John↗
NASA NTRS2005

Analysis of Effluent Gases During the CCVD Growth of Multi Wall Carbon Nanotubes from Acetylene

Catalytic chemical vapor deposition was used to grow multi-walled carbon nanotubes on a Fe:Co:CaCO3 catalyst from acetylene. The influent and effluent gases were analyzed by gas chromatography and mass spectrometry at different time intervals during the nanotubes growth process in order to better understand and optimize the overall reaction. A large number of byproducts were identified and it was found that the number and the level for some of the carbon byproducts significantly increased over time. The CaCO3 catalytic support thermally decomposed into CaO and CO2 resulting in a mixture of two catalysts for growing the nanotubes, which were found to have outer diameters belonging to two main groups 8 to 35 nm and 40 to 60 nm, respectively.

Schmitt, T. C.↗
NASA NTRS2015

Results of the GCMS Effluent Gas Analysis for the Brine Processing Test

The effluent gas for the Paragon Ionomer Water Processor (IWP), UMPQUA Ultrasonic Brine Dewatering System (UBDS), and the NASA Brine Evaporation Bag (BEB) were analyzed using Headspace GCMS Analysis in the recent AES FY14 Brine Processing Test. The results from the analysis describe the number and general chemical species of the chemicals produced. Comparisons were also made between the different chromatograms for each system, and an explanation of the differences in the results is reported.

GCMS↗
NASA NTRSDate not supplied

Plasma Abatement of Volatile Organic Compounds for Treatment of Spacecraft Trash Combustion Gaseous Effluents.

One approach that has been investigated for trash management aboard long-duration crewed exploration space missions is the so-called Trash-to-Gas approach. This technology uses a thermal process (i.e., combustion, pyrolysis, etc.) to convert crew trash into relatively non-reactive gases (i.e., CO2, CO, etc.) that can be easily vented overboard. One difficulty with this approach is the potential for the contamination of the spacecraft habitable volume from the myriad volatile organic compounds (VOCs) that are concurrently produced from these thermal processes. One possible VOC abatement process is to apply a plasma to the effluent gases. Plasmas provide high energy electrons and ions that are capable of breaking down gaseous organic species generally into smaller compounds. To explore Plasma VOC abatement, the authors constructed a plasma gas system that recirculates a particular VOCladen gas mixture through a plasma torch. This allows the periodic collection of aliquots of gaseous samples for subsequent analyses via gas chromatography mass spectrometry, designed to quantify the remaining VOC materials. The VOCs evaluated included 100 ppm of acetone, benzene, ethanol, and pentane in a background of carbon dioxide. The plasma conversion of all analytes followed first order rate kinetics, and complete VOC elimination was observed after 10 min or less of treatment, for all analytes measured. Additionally, it was observed that the plasma caused the conversion of CO2 into oxygen and CO.

Joel A. Olson↗
NASA NTRS1974

A study to identify and compare airborne systems for in-situ measurements of launch vehicle effluents

An in-situ system for monitoring the concentration of HCl, CO, CO2, and Al2O3 in the cloud of reaction products that form as a result of a launch of solid propellant launch vehicle is studied. A wide array of instrumentation and platforms are reviewed to yield the recommended system. An airborne system suited to monitoring pollution concentrations over urban areas for the purpose of calibrating remote sensors is then selected using a similar methodology to yield the optimal configuration.

Thomas, T. J.↗