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Hall, C. A.

Publications and source records attributed to Hall, C. A..

11 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Multidimensional computer simulation of Stirling cycle engines

The computer code ALGAE (algorithms for the gas equations) treats incompressible, thermally expandable, or locally compressible flows in complicated two-dimensional flow regions. The solution method, finite differencing schemes, and basic modeling of the field equations in ALGAE are applicable to engineering design settings of the type found in Stirling cycle engines. The use of ALGAE to model multiple components of the space power research engine (SPRE) is reported. Videotape computer simulations of the transient behavior of the working gas (helium) in the heater-regenerator-cooler complex of the SPRE demonstrate the usefulness of such a program in providing information on thermal and hydraulic phenomena in multiple component sections of the SPRE.

Hall, C. A.↗
NASA NTRS1977

Low thermal flux glass-fiber tubing for cryogenic service

This paper describes analytical techniques, fabrication development, and test results for composite tubing that has many applications in aerospace and commercial cryogenic installations. Metal liner fabrication is discussed in detail with attention given to resistance-welded liners, fusion-welded liners, chem-milled tubing liners, joining tube liners and end fittings, heat treatment and leak checks. Composite overwrapping, a second method of tubing fabrication, is also discussed. Test programs and analytical correlation are considered along with composite tubing advantages such as minimum weight, thermal efficiency and safety and reliability.

Hall, C. A.↗
NASA NTRS1974

Lightweight thermally efficient composite feedlines, preliminary design and evaluation

Six liquid hydrogen feedline design concepts were developed for the cryogenic space tug. The feedlines include composite and all-metal vacuum jacketed and non-vacuum jacketed concepts, and incorporate the latest technology developments in the areas of thermally efficient vacuum jacket end closures and standoffs, radiation shields in the vacuum annulus, thermal coatings, and lightweight dissimilar metal flanged joints. The feedline design concepts were evaluated on the basis of thermal performance, weight, cost, reliability, and reusability. It is shown that composite tubing provides improved thermal performance and reduced weight for each design concept considered. Approximately 12 kg (26 lb.) can be saved by the use of composite tubing for the LH2 feedline and the other propulsion lines in the space tug.

Spond, D. E.↗
NASA NTRS1974

Vacuum jacketed composite propulsion feedlines for cryogenic launch and space vehicles, volume 1

Thin metallic liners that provide leak-free service in cryogenic propulsion systems are overwrapped with a glass-fiber composite that provides strength and protection from handling damage. The resultant tube is lightweight, strong, and has a low thermal flux. The inside commodity flow line and the outside vacuum jacket were fabricated using this method. Several types of vacuum jackets were fabricated and tested at operating temperatures from 294 to 21 K (+70 to minus 423 F) and operating pressure up to 69 N/cm2 (100 psi). The primary objective of the program was to develop vacuum jacket concepts, using previously developed concepts for the inner line. All major program objectives were met resulting in a design concept that is adaptable to a wide range of aerospace vehicle requirements. Major items of development included convolution of thin metallic sections up to 46 cm (18 in.) in diameter, design and fabrication of an extremely lightweight tension membrane concept for the vacuum jacket, and analytical tools that predict the failure mode and levels.

Spond, D. E.↗
NASA NTRS1973

Composite propulsion feedlines for cryogenic space vehicles, volume 1

Thin metallic liners that provide leak-free service in cryogenic propulsion systems are overwrapped with a glass-fiber composite that provides strength and protection from handling damage. The resultant tube is lightweight, strong and has a very low thermal flux. Several styles of tubing ranging from 5 to 38 cm in diameter and up to 305 cm long were fabricated and tested at operating temperatures from 294 to 21 K and operating pressures up to 259 N/sq cm. The primary objective for the smaller sizes was thermal performance optimization of the propulsion system while the primary objective of the larger sizes was weight optimization and to prove fabricability. All major program objectives were met resulting in a design concept that is adaptable to a wide range of aerospace vehicle requirements. Major items of development included: bonding large diameter aluminum end fittings to the thin Inconel liner; fabrication of a 38 cm diameter tube from 0.008 cm thick Inconel; and evaluation of tubing which provides essentially zero quality propellant in a very short period of time resulting in a lower mass of propellant expended in chilldown.

Hall, C. A.↗
NASA NTRS1972

Low thermal flux glass-fiber tubing for cryogenic service.

Study of thin metallic liners which provide leak-free service in cryogenic propulsion plumbing systems and are overwrapped with a glass-fiber composite that provides strength and protection from handling damage. The composite tube is lightweight, strong, and has a very low thermal flux. The resultant reduced boiloff of stored cryogenic propellants yields a substantial weight savings for long-term missions (seven days or greater). Twelve styles of tubing ranging from 1/2 to 5 in. in diameter were fabricated and tested with excellent results for most of the concepts at operating temperatures from +70 to -423 F and operating pressures up to 3000 psi.

Hall, C. A.↗
NASA NTRS1972

Technology of planetary extreme environment simulation

Four test chamber systems were devleoped to simulate the extreme atmospheric environs of Venus and Jupiter, in order to assure satisfactory performance of scientific entry probes and their experiments.

Wakefield, M. E.↗