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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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Information is given on the kind of protection that is needed against impact and perforation of a long-term cryogenic storage vessel in space by meteoroids and space debris. The long-term effects of the space environment on thermal control surfaces and coatings, and the question of whether the insulation and thermal control surfaces should be encased in a vacuum jacket shell are discussed.
Compression tests were performed on representative Individual Pressure Vessel (IPV) Nickel/Hydrogen cell components in an effort to better understand the effects of force on component compression and the interactions of components under compression. It appears that the separator is the most easily compressed of all of the stack components. It will typically partially compress before any of the other components begin to compress. The compression characteristics of the cell components in assembly differed considerably from what would be predicted based on individual compression characteristics. Component interactions played a significant role in the stack response to compression. The results of the compression tests were factored into the design and selection of Belleville washers added to the cell stack to accommodate nickel electrode expansion while keeping the pressure on the stack within a reasonable range of the original preset.
Commonly encountered 'passive' insulation has been improved in recent years using 'dynamic'insulation based on closed cycle cryocoolers attached to photon shields. The paper presents a novel insulation performance measure based on ideal thermodynamic limits. Each floating insulation package has a unique value. In contrast real vessels with vent tube and supports are characterized by an 'effectiveness' less than unity.
Research shows artificial blood-vessel and heart-valve implants made more compatible with their biological environments by use of regularly microtextured surfaces. In new manufacturing process, ion beam etches patterned array of small pillars on mandrel used to mold tubular plastic implant. Pillars create tiny regularly spaced holes in inner surface of tube. Holes expected to provide sites for attachment of healthy lining. Polytetrafluoroethylene (PTFE) used as mandrel material because it can be etched by ion beam.
Method for making fiber-reinforced composite structure relies on heating and differential thermal expansion to provide temperature and pressure necessary to develop full strength, without having to place structure in large, expensive autoclave. Layers of differentially expanding material squeeze fiber-reinforce composite between them when heated. Method suitable for such cylindrical structures as pressure vessels and tanks. Used for both resin-matrix and metal-matrix composites.
Compression tests were performed on representative Individual Pressure Vessel (IPV) Nickel/Hydrogen cell components in an effort to better understand the effects of force on component compression and the interactions of components under compression. It appears that the separator is the most easily compressed of all of the stack components. It will typically partially compress before any of the other components begin to compress. The compression characteristics of the cell components in assembly differed considerably from what would be predicted based on individual compression characteristics. Component interactions played a significant role in the stack response to compression. The results of the compression tests were factored into the design and selection of Belleville washers added to the cell stack to accommodate nickel electrode expansion while keeping the pressure on the stack within a reasonable range of the original preset.
Tests were performed on candidate graphite yarns for the overwraps to be used on the Space Station Freedom's pressure vessels. The objective was to determine the performance and ranking of these overwraps to ensure that sustained loads would not be a problem during their 30-yr life in space. Tests were conducted at high stress levels for short time periods on subscale composite bottles. The average delivered fiber stresses were determined from the measured burst pressures via SCI analysis that accounts for both geometry and the properties of the resin and yarn.
Experimental results are reported for submerged injection pressurization and expulsion tests of a 4.89 cu m liquid hydrogen tank. The pressurant injector was positioned near the bottom of the test vessel to simulate liquid engulfment of the pressurant gas inlet; a condition that may occur in low-gravity conditions. Results indicate a substantial reduction in pressurization efficiency, with pressurant gas requirements approximately five times greater than ideal amounts. Consequently, submerged vapor injection should be avoided as a low-gravity autogenous pressurization method whenever possible. The work presented herein validates that pressurent requirements are accurately predicted by a homogeneous thermodynamic model when the submerged injection technique is employed.
Information is given in viewgraph form on a nickel-hydrogen common pressure vessel spaceflight experiment. Information given includes the schedule and diagrams of the electrical power subsystem and control features.
Information is given in viewgraph form on the nickel hydrogen common pressure vessel (CPV) 2.5V twin stack cell designs. Information given includes an energy analysis, a CPV design comparison, a summary of CPV characterization testing, a comparison of discharge voltage among designs, and life test performance summaries.
An improved bio-reactor vessel and system useful for carrying out mammalian cell growth in suspension in a culture media are presented. The main goal of the invention is to grow and maintain cells under a homogeneous distribution under acceptable biochemical environment of gas partial pressures and nutrient levels without introducing direct agitation mechanisms or associated disruptive mechanical forces. The culture chamber rotates to maintain an even distribution of cells in suspension and minimizes the length of a gas diffusion path. The culture chamber design is presented and discussed.
Over 7000 low-earth-orbit (LEO) cycles were demonstrated on a full-size aerospace common pressure vessel (CPV) prototype. The battery demonstrated the capability of the basic CPV design to meet the life and reliability requirements of aerospace missions. Subsequent design modifications have been employed to address the shortcomings of the original design and several new prototypes have been fabricated. These include a 12-cell 125 amp-hour geosynchronous earth-orbit (GEO) battery and a 22-cell 10.5 amp-hour LEO battery. Cells for an 80-cell battery intended to demonstrate the high voltage capability of the CPV design have also been fabricated. In addition, assembly of a 20-cell aircraft starting battery prototype is in progress, and testing of a group of 12-volt, 160 amp-hour terrestrial batteries is continuing.
A Gas Vessel Assembly has been developed that delivers purified, very low moisture content gas at two different output pressures. High pressure gas is delivered at up to 6,700 psi, and low pressure gas regulated to 130 psi is also delivered via a second outlet over a wide range of flow rates. The device is extremely lightweight (less than 1 lb) and compact, affords maximum mechanical integrity, high reliability (0.9999 at 95 percent confidence level), and offers extremely long storage life. Specialized design and fabrication techniques are employed that guarantee gas purity and negligible leakage for more than 20 years, in widely varying conditions of storage temperature, humidity, altitude, and vibration environments. The technology offers unique advantages in fast, high pressure discharge applications. For example, when combined with a cryostat, cryogenic temperatures can be achieved such as those used in missile seeker technology. The technology has many additional applications such as: emergency power sources for safety devices such as those needed in nuclear power plants, refineries, collision cushioning devices, superconductor cooling devices, emergency egress systems, miniature mechanical devices that employ gas bearings, and other areas where long storage, extremely high reliability and/or high energy density sources are required.
This guide is intended to provide methodology and describe the intent of the Pressure Vessel and System (PV/S) Certification program. It is not meant to be a mandated document, but is intended to transmit a basic understanding of the PV/S program, and include examples. After the reader has familiarized himself with this publication, he should have a basic understanding of how to go about developing a PV/S certification program.
A two-dimensional and time-dependent thermal model of a multicell common pressure vessel (CPV) nickel-hydrogen battery was developed. A finite element solver called PDE/Protran was used to solve this model. The model was used to investigate the effects of various design parameters on the temperature profile within the cell. The results were used to help find a design that will yield an acceptable temperature gradient inside a multicell CPV nickel-hydrogen battery. Steady-state and unsteady-state cases with a constant heat generation rate and a time-dependent heat generation rate were solved.
The effect of local ply fiber fracture on the load-carrying capability and structural behavior of a composite cylindrical shell under internal pressure is investigated, using the CODSTRAN computer code to simulate the composite structural degradation under loading. Results show that an initial outer-surface defect in the vessel begins to grow at a relatively low pressure but exhibits localized gradual damage growth prior to structural fracture and that an initial inner-surface defect shows an overall damage progression and fracture behavior closely similar to that of the outer surface defect. An initial defect located near the mid-thickness of the shell requires a higher pressure to cause damage initiation, but, once the damage initiation pressure is reached, a sudden structural fracture stage is entered by rapid damage propagation at a slightly higher pressure.
Experimental results are reported for submerged injection pressurization and expulsion tests of a 4.89 cu m liquid hydrogen tank. The pressurant injector was positioned near the bottom of the test vessel to simulate liquid engulfment of the pressurant gas inlet, a condition that may occur in low-gravity conditions. Results indicate a substantial reduction in pressurization efficiency with pressurant gas requirements approximately five times greater than ideal amounts. Consequently, submerged vapor injection should be avoided as a low-gravity autogenous pressurization method whenever possible. The work presented herein validates that pressurant requirements are accurately predicted by a homogeneous thermodynamic model when the submerged injection technique is employed.
Prediction of whether a pressurized cylinder will fail catastrophically when impacted by a projectile has important applications ranging from perforation of an airplane's skin by a failed turbine blade to meteorite impact of a space station habitation module. This report summarizes the accomplishment of one task for a project whose aim is to simulate numerically the outcome of a high velocity impact of pressure vessels. A finite element patch covering the vicinity of a growing crack has been constructed to estimate the J-integral (crack driving force) during the impact. Explicit expressions for the J-integral through the nodal values of displacement, strain, and stress have been written. The patch is to be used repeatedly to estimate the amount of crack growth during the time of the impact. The resulting crack size is to be compared to an estimated critical crack size for the pressurized cylinder.