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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1981

JT9D performance deterioration results from a simulated aerodynamic load test

The results of testing to identify the effects of simulated aerodynamic flight loads on JT9D engine performance are presented. The test results were also used to refine previous analytical studies on the impact of aerodynamic flight loads on performance losses. To accomplish these objectives, a JT9D-7AH engine was assembled with average production clearances and new seals as well as extensive instrumentation to monitor engine performance, case temperatures, and blade tip clearance changes. A special loading device was designed and constructed to permit application of known moments and shear forces to the engine by the use of cables placed around the flight inlet. The test was conducted in the Pratt & Whitney Aircraft X-Ray Test Facility to permit the use of X-ray techniques in conjunction with laser blade tip proximity probes to monitor important engine clearance changes. Upon completion of the test program, the test engine was disassembled, and the condition of gas path parts and final clearances were documented. The test results indicate that the engine lost 1.1 percent in thrust specific fuel consumption (TSFC), as measured under sea level static conditions, due to increased operating clearances caused by simulated flight loads. This compares with 0.9 percent predicted by the analytical model and previous study efforts.

Stakolich, E. G.↗
NASA NTRS1981

Failure analysis methods for capacitors

The basic steps in the failure analysis of discrete capacitors used in electronic circuit boards and hybrid assemblies are described. These steps include: visual examination; functional test; disassembly; isolation of the failure site; and documentation.

Hildenbrand, R. L.↗
NASA NTRS1980

Space Shuttle cargo processing.

The spacecraft processing techniques to be used at the Kennedy Space Center for the assembly and check-out of Space Shuttle cargoes are discussed. The processing flow for vertically handled spacecraft, which are inserted into the Shuttle orbiter cargo bay while the orbiter is in the vertical position and often are attached to a separate solid booster stage, includes assembly into unified payloads in the Vertical Processing Facility, followed by Cargo Integration Test Equipment tests to ensure cargo bay compatibility, and transportation to the launch pad. Horizontally handled spacecraft such as Spacelab, which are inserted into the Orbiter cargo bay while it is in the Orbiter Processing Facility in the horizontal position, are assembled and checked out within the Operations and Checkout Building, where the CITE tests are performed and the Spacelab will be disassembled, and then transported to the Orbiter Processing Facility. It is pointed out that during the Space Shuttle era, when the number of spacecraft to be processed simultaneously at Kennedy will double or triple, all spacecraft processing facilities will be required to handle the workload.

Neilon, J. J.↗
NASA NTRS1981

Performance analysis of SA-3 missile second stage

One SA-3 missile was disassembled. The constituents of the second stage were thoroughly investigated for geometrical details. The second stage slotted composite propellant grain was subjected to mechanical properties testing, physiochemical analyses, and burning rate measurements at different conditions. To determine the propellant performance parameters, the slotted composite propellant grain was machined into a set of small-size tubular grains. These grains were fired in a small size rocket motor with a set of interchangeable nozzles with different throat diameters. The firings were carried out at three different conditions. The data from test motor firings, physiochemical properties of the propellant, burning rate measurement results and geometrical details of the second stage motor, were used as input data in a computer program to compute the internal ballistic characteristics of the second stage.

Helmy, A. M.↗
NASA NTRS1981

JT9D performance deterioration results from a simulated aerodynamic load test

This paper presents the results of testing to identify the effects of simulated aerodynamic flight loads on JT9D engine performance. The test results were also used to refine previous analytical studies on the impact of aerodynamic flight loads on performance losses. To accomplish these objectives, a JT9D-7AH engine was assembled with average production clearances and new seals as well as extensive instrumentation to monitor engine performance, case temperatures, and blade tip clearance changes. A special loading device was designed and constructed to permit application of known moments and shear forces to the engine by the use of cables placed around the flight inlet. The test was conducted in the Pratt and Whitney Aircraft X-Ray Test Facility to permit the use of X-ray techniques in conjunction with laser blade tip proximity probes to monitor important engine clearance changes. Upon completion of the test program, the test engine was disassembled, and the condition of gas path parts and final clearances were documented. The test results indicate that the engine lost 1.1 percent in thrust specific fuel consumption (TSFC), as measured under sea level static conditions, due to increased operating clearances caused by simulated flight loads. This compares with 0.9 percent predicted by the analytical model and previous study efforts.

Stakolich, E. G.↗
NASA NTRS1981

Study to define an approach for developing a computer-based system capable of automatic, unattended assembly/disassembly of spacecraft, phase 1

The initial set of requirements for additional studies necessary to implement a space-borne, computer-based work system capable of achieving assembly, disassembly, repair, or maintenance in space were developed. The specific functions required of a work system to perform repair and maintenance were discussed. Tasks and relevant technologies were identified and delineated. The interaction of spacecraft design and technology options, including a consideration of the strategic issues of repair versus retrieval-replacement or destruction by removal were considered along with the design tradeoffs for accomplishing each of the options. A concept system design and its accompanying experiment or test plan were discussed.

Nevins, J. L.↗
NASA NTRS1980

Development of a process for high capacity arc heater production of silicon for solar arrays

A high temperature silicon production process using existing electric arc heater technology is discussed. Silicon tetrachloride and a reductant, liquid sodium, were injected into an arc heated mixture of hydrogen and argon. Under these high temperature conditions, a very rapid reaction occurred, yielding silicon and gaseous sodium chloride. Techniques for high temperature separation and collection of the molten silicon were developed. The desired degree of separation was not achieved. The electrical, control and instrumentation, cooling water, gas, SiCl4, and sodium systems are discussed. The plasma reactor, silicon collection, effluent disposal, the gas burnoff stack, and decontamination and safety are also discussed. Procedure manuals, shakedown testing, data acquisition and analysis, product characterization, disassembly and decontamination, and component evaluation are reviewed.

Meyer, T. N.↗
NASA NTRS1981

Long term behavior of silicon germanium thermoelectric generators

Results of tests of the long term performance of SiGe radioisotope thermoelectric generators (RTG) are presented. Three modules were monitored for 17,000-32,300 hr at hot junction temperatures of 1,085, 1,055, and 1,000 C; coating the unicouples with a 12,000 A thick layer of Si3N4 protected the modules from Si sublimation. Output degraded less than 0.3-0.4%/1,000 hr over the testing period. Life tests on a multihundredwatt (MHW) SiGe generator with 312 couples at a hot shoe temperature of 1,040 C dealt with power of 150 W at 30 V, with 0.5%/1,000 hr performance degradation. Si deposition on the insulation was found to enhance electrical conductance until a saturation point was reached. Disassembly of a test module after 16,750 hr revealed a Mo build-up, SiN4 coating deterioration, and Ti diffustion from the hot shoe to cooler regions of the junction. The presence of an Al2O3 insulator was recognized as preventing coating loss. Performance records from the Voyager and Les-8 satellites' RTG's are compared and show similar, 0.25%/1,000 hr degradation rates; RTG storage is judged to be feasible and the tests lead to projections of a 600,000 hr lifetime for a SiGe RTG.

Shields, V.↗
NASA NTRS1983

Staked Bearing Removal Tool

Tool with assembled components expedites bearing replacement in aircraft, ground vehicles, and other applications. New tool cuts lip on one side to facilitate bearing replacement. After bearing retaining lip is cut away, bearing pressed out. Tool makes it possible to replace bearings without disassembling structure.

Berson, L. A.↗
NASA NTRS1983

Testing Bearings in Tight Spaces

Portable tool checks bushings and bearings in hard-to-reach places to ensure they are properly staked. Actuator plate with surfaces at 45 degrees to hydraulic cylinder shaft turns push or pull perpendicular to original direction. Tool makes unnecessary to disassemble equipment to gain access to parts.

Bird, R. G.↗
NASA NTRS1984

Ice as an Abrading Agent

Grit-blasting method makes unnecessary to disassemble equipment for cleaning. Stream of small, frozen pellets directed at assembly to be cleaned. Pellets consist of deionized-water ice, carbon dioxide ice, or another substance that does not react chemically with parts to be cleaned and leaves no residue. Method suited to cleaning titanium and parts that touch liquid oxygen.

Blow, R. K.↗
NASA NTRS1984

Bellows With Longitudinal Beams

Bellows assembled using two longitudinal side seams allow seam joints to be placed in axial directions of bellows. Design of particular importance in difficult situations where frequent assembly or repair required or in limited-access areas not desirable to disassemble total unit to replace one-piece bellows.

Garvin, W.↗
NASA NTRS1983

Design of a safe cylindrical lithium/thionyl chloride cell

Cell design criteria were established which can result in a safe lithium/thionyl chloride cell. A cell vent, a low area internal anode cell, cell balance and composition of the cathode-electrolyte solution were found to be important factors in the design of a safe cell. In addition to routine testing, both undischarged and discharged cells were subjected to electrical abuse, environmental abuse and mechanical abuse without disassembly.

Johnson, D. H.↗
NASA NTRS1985

Fabricating Underwater Electroacoustic Transducers

Use of retainer ring instead of adhesives simplifies assembly and disassembly. Underwater electroacoustical transducer assembly uses precast silicone rubber compressed between ceramic crystal and metal container. Removable retainer ring holds assembly in place. Method provides proper stress loading, speed and ease of assembly, and way of removing transducer without damaging crystal.

Ferguson, R. L.↗
NASA NTRS1983

Electromagnetic levitation coil fabrication technique for MSFC containerless processing facilities

A technique is described for more reproducible fabrication of electromagnetic levitation coils. A split mandrel was developed upon which the coil is wound. After fabrication the mandrel can be disassembled to remove it from the coil. Previously, a full day was required to fabricate a levitation coil and the success rate for a functional coil was only 50 percent. About eight coils may be completed in one day using the technique developed and 95 percent of them are good levitation coils.

Ethridge, E. C.↗
NASA NTRS1983

Intelligent editor/printer enhancements

Microprocessor support hardware, software, and cross assemblers relating to the Motorola 6800 and 6809 process systems were developed. Pinter controller and intelligent CRT development are discussed. The user's manual, design specifications for the MC6809 version of the intelligent printer controller card, and a 132-character by 64-line intelligent CRT display system using a Motorola 6809 MPU, and a one-line assembler and disassembler are provided.

Woodfill, M. C.↗
NASA NTRS1984

Failure Analysis of Nickel-hydrogen Cell Subjected to Simulated Low Earth Orbit Cycling

A nickel-hydrogen cell completed 10,080 simulated low earth orbit charge/discharge cycles at depths-of-discharge ranging from 50 to 80 percent prior to failure. The cell is of the Air Force design, rated at 50 ampere-hours, 8.9 cm (3.5 inches) in diameter. Upon disassembly, the end of the polysulfone core supporting the electrode stack was found to have fractured. This allowed the electrode stack to expand. A massive short was found at the inner diameter of the electrodes centered roughly at plate set 34 to 37 from the positive end of the electrode stack. The damaged area extended through approximately one third of the electrode stack, with the effect becoming progressively less with distance from plate set 34 to 37. Measured thicknesses of the positive plates were significantly greater than the initial specification values. The postulated cause of failure is that positive plate growth caused fracture of the shoulder from the end of the polysulfone core on which the electrodes are mounted. The electrode stack relieved and pressure points were created at the area near the inner diameter of the plates at the tab attachment. A short occurred at a pressure point between opposing plates and propagated to other electrode sets due to thermal and mechanical stresses caused by the short.

Mueller, V. C.↗
NASA NTRS1986

Noninvasive Fluid Level Sensor for Organometallic Sources

Two ultrasonic methods available for measuring level of organometallic liquid in stainless-steel (or other homogeneous solid) container. Methods require no disassembly or weighing of container. Commercially available ultrasonic flaw detectors, some of which have digital readouts and computer interfaces, used in techniques. Both methods used in crystal growth to determine level of liquids contained in sealed, opaque containers.

Gerdes, W.↗