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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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Cold testing method prevents formation of frost on printed circuit boards and part holders during testing at sub-zero temperatures. Freon permits rapid attainment of the required testing temperature.
N-heptane and Freon-13 droplets vaporizing size and temperature at supercritical pressures in heated air stream
Freon-12 applied to tool cutting edge evaporates quickly, leaves no residue, and permits higher cutting rate than with conventional coolants. This technique increases cutting rate on Rene-41 threefold and improves finish of machined surface.
Fluidic controls for automotive engine examined by Rankine cycle performance with water, CP-34, and freon TF and investigation for boiler and feed pump control criteria
N-heptane, carbon dioxide and Freon 13 droplet vaporization measurements at supercritical pressure, comparing with film theory calculation
Mobile transport system, that can be carried by truck and parked in storage area, consists of an inner container capable of holding 363 kg of diborane and an external, dual refrigeration unit which uses liquid nitrogen and Freon-14.
Development of system for storing cryogenic propellants in multiple tank configuration is discussed. System uses single loop and closed loop features. Liquid nitrogen and Freon-14 are used as refrigerants. Diagram of equipment to show components and operation is provided.
A theoretical and experimental investigation is described on multiple pure tone noise. Based on a two-dimensional and inviscid flow model, an analysis is developed to predict the generation and subsequent evolution of multiple pure tone noise from prescribed blade-to-blade nonuniformities in the rotor geometry. The results show that even small nonuniformities within manufacturing tolerances can cause a significant amount of multiple pure tone noise. Among the different kinds of nonuniformities investigated, errors in blade spacings are a weaker generator of multiple pure tone noise than errors in blade stagger or blade contours. Experimental investigations of the effects of the rotor relative Mach number, incidence angle and length of the inlet duct on the evolution of the multiple pure tone noise are conducted with a known distribution of rotor nonuniformities. The model fan is operated, in Freon 12, in a closed loop acoustical facility.
Flow tests were conducted on models of the gas core (cavity) reactor. Variations in cavity wall and injection configurations were aimed at establishing flow patterns that give a maximum of the nuclear criticality eigenvalue. Correlation with the nuclear effect was made using multigroup diffusion theory normalized by previous benchmark critical experiments. Air was used to simulate the hydrogen propellant in the flow tests, and smoked air, argon, or freon to simulate the central nuclear fuel gas. All tests were run in the down-firing direction so that gravitational effects simulated the acceleration effect of a rocket. Results show that acceptable flow patterns with high volume fraction for the simulated nuclear fuel gas and high flow rate ratios of propellant to fuel can be obtained. Using a point injector for the fuel, good flow patterns are obtained by directing the outer gas at high velocity along the cavity wall, using louvered or oblique-angle-honeycomb injection schemes.
The Pioneer F/G spacecraft achieves the desired earth-pointing direction through a system requiring the shifting of the main antenna feed 1 in. off axis. The feed is pivoted to this position by an electrically heated thermal actuator consisting of an electroless nickel bellows in a copper housing and filled with Freon 21. The actuator overtravels and maintains the feed in the offset position in a thermostatic limit cycle operation mode until commanded off. The mechanism is expected to operate in a -240 F environment near Jupiter and was successfully tested at such temperatures.
A thermally insulative inflatable garment designed specifically as a lightweight low storage volume emergency suit for subzero weather survival is reported. Testing confirms that the inflatable suit design satisfies the objectives for a subject standing at rest with environmental temperatures down to -450 F if the garment is inflated with Freon.
A series of flowing gas experiments using air, argon, and freon has been conducted in Idaho. The purpose is to study methods of obtaining flow patterns which would create maximum possible system reactivity consistent with an acceptably low uranium to coolant-gas loss ratio. These have been conducted on both ?two-dimensional' and truly three-dimensional spherical configurations of diameters 18 to 42 inches. The larger diameter is that proposed for a minimum cost flowing gas critical experiment, and the size extremes make extrapolations to the large 6 and 8 foot diameter configurations more reliable. Results show that large enough inner gas (fuel) volume fractions can be achieved to attain criticality.
Description of an oscillating magnetic analyzer (KDP crystal plus Glan-Thompson prism) coupled to an echelle-interferometer spectrograph, and of single-slit magnetometer which by pressure variations can be made to scan the entire profiles of the circularly and linearly polarized Zeeman components. Freon gas is used as the scanner gas with wavelength displacements of 0.02 A per 0.1 in. Hg pressure change at the NaD lines. The available scan range is 15 A in the visual spectral region.
An investigation on multiple pure tone (MPT) noise is described. The model fan is operated, in Freon 12, in a closed loop acoustical facility. It has been found experimentally that the rotor relative Mach number and incidence angle are parameters important to the evolution of the MPT sound and the inlet duct length has a significant influence on the MPT sound emission. The experimental results are compared with a previous analysis. From the known blade nonuniformities of the model fan, the MPT distributions are computed. The analysis correctly predicts the frequency of the dominant multiple pure tone and sound pressures of the blade passing frequency noise and the dominant MPT that are in the same range as the experimental values.
Surface pressures, heat-transfer rates, and transition locations for a sharp cone (whose semivertex angle is 12 deg) were obtained in a hypervelocity wind tunnel at a free-stream Mach number of 12 and a free-stream Re/ft range of 3,000,000 to 6,000,000. The effects of injecting either methane, nitrogen, or Freon-22 (at rates up to 2.1% of free-stream rate) were studied for a uniform injection-distribution and for a variable injection-distribution. Gaseous injection had little effect on the surface pressure measurements. For a given mass injection distribution, the laminar region heat-transfer decreases as the injection rate increases or as the molecular weight of the injectant decreases. For a given mass-injection rate (integrated over the surface of the entire cone), the transition location and heat-transfer rates were sensitive to the injection distribution. The transition Reynolds numbers were significantly greater when the local injection rate was constant over the surface of the cone.
A group of 50 workers, exposed for an average of 2.77 years in an environment, samples of which contained from 46 to 4700 ppm of trichlorotrifluoroethane (Freon 113), was examined. There were no subjective complaints, other than one case of dryness of the skin, referable to this occupational exposure. At this time, it is our opinion that there is no evidence of adverse effects from exposure to trichlorotrifluoroethane under the conditions encountered by these personnel. We believe that continued, periodic, follow-up examinations of these workers will be helpful in further evaluating any possible long-range effects of this material.
Use of a Fabry-Perot interferometer in a Ramsay mount in tandem with an echelle Hilger monochromator with pinholes instead of slits. The instrument, URSIES, is enclosed within a pressure chamber filled with Freon. Photoelectric pulse counting techniques and pressure scanning are used to record the spectrum. This design has four basic advantages: (1) the resolution of the scanner is variable from 5.0 to 0.005 A, and the effective wavelength range is quite broad, from 3500 to 13,000 A; (2) a light gain of ten over conventional grating scanners at resolutions of 0.1 A or better is achieved; (3) very low levels of light from outside the wavelength passband reach the detector; for a resolution of 0.03 A at 6000 A this level is 5%; and (4) there are very low levels of scattered light from the pinholes when extended sources are observed. The scattered light from the instrument at the edge of the solar disk is found to be less than 1% from 4000 to 11,000 A. Measurements demonstrating these advantages are discussed.
Discussion of an analytical model which leads to predictions of reductions in electron concentrations in reentry flow fields due to the injection of electrophilic liquids and water. The processes incorporated into the model are: penetration and breakup of the liquid jet, droplet acceleration and vaporization, expansion of the liquid spray due to droplet vaporization, electrophilic vapor diffusion, heterogeneous and homogeneous charged species recombination kinetics and homogeneous electron attachment kinetics. Spray boundary calculations are shown to be in good agreement with photographic observations of water and Freon E-3 sprays in wind tunnel tests of a scale model RAM C-III flight vehicle. Fixed-bias electrostatic probe data taken during the RAM C-III flight are interpreted in terms of effective jet penetration distances - which are shown to be consistent with calculations using the present model.