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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 523 records · Page 29
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

NASA clean catalytic combustor program

The successful operation of an aircraft gas turbine combustion system incorporating a state-of-the-art catalytic reactor as the main stage, along with a conventional pilot stage for low power operation, is reported to have been achieved with high combustion efficiency at moderate engine pressure ratios. The extremely low nitrogen oxides emission level taken by the program as its goal has also been achieved. It is noted that significant improvements in the operating temperature capability of catalytic reactor materials will be required for the successful application of such devices to the very high pressure ratio, high temperature engines assumed to be the ultimate application of the devices studied.

Ekstedt, E. E.↗
NASA NTRS1985

Cleaning The Walls of A Silane Reactor

Scraper removes silicon deposits from inner walls of reactor vessel. Scraper supported by gas bearing. Scraper made of non-contaminating material such as quartz or silicon.

Yamakawa, K. A.↗
NASA NTRS1983

Clean catalytic combustor program

A combustor program was conducted to evolve and to identify the technology needed for, and to establish the credibility of, using combustors with catalytic reactors in modern high-pressure-ratio aircraft turbine engines. Two selected catalytic combustor concepts were designed, fabricated, and evaluated. The combustors were sized for use in the NASA/General Electric Energy Efficient Engine (E3). One of the combustor designs was a basic parallel-staged double-annular combustor. The second design was also a parallel-staged combustor but employed reverse flow cannular catalytic reactors. Subcomponent tests of fuel injection systems and of catalytic reactors for use in the combustion system were also conducted. Very low-level pollutant emissions and excellent combustor performance were achieved. However, it was obvious from these tests that extensive development of fuel/air preparation systems and considerable advancement in the steady-state operating temperature capability of catalytic reactor materials will be required prior to the consideration of catalytic combustion systems for use in high-pressure-ratio aircraft turbine engines.

Ekstedt, E. E.↗
NASA NTRS1983

Exospheric cleaning of the Earth Radiation Budget solar radiometer during solar maximum

Anomalous behavior of the Earth Sensor Assemblies (ESA) had been observed on the Defense Meteorological Satellite Program (DMSP) 5D/1 satellites and the Tiros-N satellite. The present investigation is concerned with the reasons for the observed phenomena. Degradation of the Earth Radiation Budget (ERB) solar channels and the Solar Backscatter Ultraviolet and Total Ozone Mapping Spectrometer (SBUV/TOMS) diffuser plate is attributed to transmission or reflection loss originating from the growth of an organic film by photolytic polymerization. Simultaneous degradation of the ESA interference filter coated lenses facing the flight direction and the recovery of the ERB solar channels on Nimbus 6 and 7 is caused by a reaction with the increase in the exospheric atmospheric density caused by solar maximum.

Predmore, R. E.↗
NASA NTRS1983

Surface studies with (clean) supported metal particles and clusters

Small particles are ideal for combined studies with surface analytical and electron microscopy/diffraction methods. In this way crystallography, microstructure, morphology, physical stability, and electronic structure can be correlated directly with chemical reactivity. Various integrated experimental approaches for conducting model studies with UHV-evaporated particles have been successfully developed; they entail the use of TPD, AES, XPS, and work function measurements on one hand and standard TEM/TED, in-situ TEM/TED, and in-situ STED/TEM techniques on the other hand. The essential features of four particular experimental approaches are discussed and a selection of representative results is presented to illustrate the potential usefulness of such studies in the field of catalysis.

Poppa, H. R.↗
NASA NTRS1985

Copyboard Quickly Makes Clean Printing Plates

Vacuum-chuck eliminates glass and sponge artwork support. Vacuum copyboard allows camera-ready original slid on top plate for proper positioning, then holds securely for photography. Bleed valve allows vacuum in copyboard box adjusted for small or large originals. With new copyboard, time-consuming and costly procedures unnecessary.

Balandis, W. D.↗
NASA NTRS1985

Preliminary study of gaseous nitrogen-liquid oxygen mixing and self cleaning

The penetration of gaseous nitrogen into liquid oxygen at a pressure of 150 psi was determined by monitoring the composition of the evaporating liquid in a nitrogen analyzer. For pressurization times of about 1 hr the penetration depth varies between 0.0024 and 0.018 in. at an evaporation rate of about 1 gal/day. These are small compared to the penetration depth of 22.2 in. measured in the 7-inch high temperature tunnel at a pressure of 1500 psi, pressurization time of 5 min, and evaporation rate of 121 gal/day.

Zuckerwar, A. J.↗
NASA NTRS1989

Cleanly Burning Squib

Ignition wire repositioned to suppress unburned particles. In new configuration, ignition coil located near top of combustion chamber. As charge burns, unburned portion held at bottom of chamber. Little or no unburned charge ejected. Nearly uniform pressure generated, and only gases ejected from combustion chamber.

Bickler, Donald B.↗
NASA NTRS1988

The moon: An abundant source of clean and safe fusion fuel for the 21st century

It is shown how helium-3 can be obtained from the moon and how its use in fusion reactors can benefit the inhabitants of this planet. The physics and technology issues associated with the use of He-3 is addressed. A description is given of He-3 distribution on the moon and of methods which could be used to retrieve it.

Kulcinski, G. L.↗
NASA NTRS1989

Chemical consequences of the initial diffusional growth of cloud droplets - A clean marine case

A simple microphysical cloud parcel model and a simple representation of the background marine aerosol are used to predict the concentrations and compositions of droplets of various sizes near cloud base. The aerosol consists of an externally-mixed ammonium bisulfate accumulation mode and a sea-salt coarse particle mode. The difference in diffusional growth rates between the small and large droplets as well as the differences in composition between the two aerosol modes result in substantial differences in solute concentration and composition with size of droplets in the parcel. The chemistry of individual droplets is not, in general, representative of the bulk (volume-weighted mean) cloud water sample. These differences, calculated to occur early in the parcel's lifetime, should have important consequences for chemical reactions such as aqueous phase sulfate production.

Twohy, C. H.↗
NASA NTRS1989

Results of correlations for transition location on a clean-up glove installed on an F-14 aircraft and design studies for a laminar glove for the X-29 aircraft accounting for spanwise pressure gradient

Results of correlative and design studies for transition location, laminar and turbulent boundary-layer parameters, and wake drag for forward swept and aft swept wings are presented. These studies were performed with the use of an improved integral-type boundary-layer and transition-prediction methods. Theoretical predictions were compared with flight measurements at subsonic and transonic flow conditions for the variable aft swept wing F-14 aircraft for which experimental pressure distributions, transition locations, and turbulent boundary-layer velocity profiles were measured. Flight data were available at three spanwise stations for several values of sweep, freestream unit Reynolds number, Mach numbers, and lift coefficients. Theory/experiment correlations indicate excellent agreement for both transition location and turbulent boundary-layer parameters. The results of parametric studies performed during the design of a laminar glove for the forward swept wing X-29 aircraft are also presented. These studies include the effects of a spanwise pressure gradient on transition location and wake drag for several values of freestream Reynolds numbers at a freestream Mach number of 0.9.

Goradia, S. H.↗
NASA NTRS1992

Tools Make Clean Holes In Honeycomb Panels

Three tools designed used together to prepare honeycomb panels for insertion of hardware to support structural members or electronic packages. Tools speed up and simplify time-consuming operation of manually pushing honeycomb material aside to make room for spool-shaped mounting insert. Tools are core cutter, spotface cutter, and displacement tool.

Wells, Dott↗
NASA NTRS1992

Diurnal HO2 cycles at clean air and urban sites in the troposphere

HO2 concentrations at two Oregon sites were determined for continuous periods of 36 to 48 hours, using fluorescence assay with gas expansion. At the sea level coastal site, NNW winds prevailed during daytime, and a point measurement of very low total nonmethane hydrocarbon concentration indicated the presence of remote tropospheric air of oceanic origin. At the urban site, HO2 was determined during moderately low ozone pollution levels. At both sites, maximum daily (HO2) was in the range of 1-2 x 10 exp 8/cu cm under clear-sky conditions, with an estimated overall uncertainty of 40 percent. HO2 was detected by continuous low-pressure sampling with flowing chemical conversion to HO, which was detected by laser-excited fluorescence. The instrumental response to HO2 was calibrated by the self-decay of HO2 at atmospheric pressure. Interference in the measured daytime HO2 concentrations by RO2 was estimated at less than 20 percent.

Hard, T. M.↗
NASA NTRS1992

Parametric and time resolved studies of autoignition and flameholding in a clean-air supersonic combustor

A model scramjet combustor was tested using transverse sonic injection of gaseous hydrogen behind a rearward facing step. It was found that ignition in the constant area duct initiates well downstream and propagates upstream with velocities ranging from 300 to nearly 1,000 m/s in the laboratory frame. The downstream ignition develops into a detonation wave prior to reaching the region of observation. A number of parameters including fuel flow rate, air stagnation temperature and pressure, and the operating conditions of the downstream air ejector affected ignition conditions.

Whitehurst, R. B.↗
NASA NTRS1992

A clean air continuous flow propulsion facility

Consideration is given to a contaminant-free, high enthalpy, continuous flow facility designed to obtain detailed code validation measurements of high speed combustion. The facility encompasses uncontaminated air temperature control to within 5 K, fuel temperature control to 2 K, a ceramic flow straightener, drying of inlet air, and steady state continuous operation. The air heating method provides potential for independent control of contaminant level by injection, mixing, and heating upstream. Particular attention is given to extension of current capability of 1250 K total air temperature, which simulates Scramjet enthalpy at Mach 5.

Krauss, R. H.↗
NASA NTRS1993

Clean Electrical-Discharge Machining Of Delicate Honeycomb

Precise recesses in fragile metal honeycomb blocks formed in special electrical-discharge machining process. Special tooling used, and recesses bored with workpiece in nonstandard alignment. Cutting electrode advances into workpiece along x axis to form pocket of rectangular cross section. Deionized water flows from fitting, along honeycomb tubes of workpiece, to electrode/workpiece interface.

Johnson, Clarence S.↗