Development of a hemispherical metal diaphragm for single-cycle liquid-metal positive expul- sion systems
Metallic expulsion diaphragm for single-cycle positive expulsion of high temperature liquid in gravity condition
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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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Use of thin plastic films at cryogenic temperatures
Commercially available plastic film materials that remain flexible at cryogenic temperatures and resist failures caused by folds and wrinkles created during expulsion were investigated for use in expulsion bladders for liquefied gases. Compatible adhesive systems, fabrication techniques, and results of impact and dynamic loading tests are summarized.
Lark, R. F.↗
A numerical hydrodynamic study of coalescence in head-on collisions of identical stars.
The specific results reported refer to head-on collisions between identical polytropes of index 3 having solar mass and radius. If the polytropes were initially at rest at infinity, then about 5% of the combined mass is lost by ejection following collision. The volatilized mass fraction rises to about 18% for an initial relative collision velocity of 1000 km/sec at infinite separation, and to about 60% for the 2000 km/sec case. Since the initial kinetic and gravitational energies balance for a relative velocity of 1512 km/sec at infinity, it may be seen that net coalescence persists to velocities somewhat in excess of this figure. Mass ejection takes place in two ways simultaneously: (1) by a rapid sideward expulsion of fluid in a massive lateral sheet normal to the collision axis, and (2) as a result of two recoil shocks which lead momentum flows backward along this axis. The lateral effect has similarities to the expansion of gas into a vacuum i.e., shocks are not involved. However, the ejection of material from the rear colliding hemisphere due to the recoil shocks predominates at low collision velocities. As the velocity increases, both effects strengthen, but the lateral expulsion intensifies more rapidly than the recoil shocks.
Seidl, F. G. P.↗
Dynamical and photometric investigation of cometary type 2 tails
The absolute calibration of the photometric profile of the antitail of Comet Kohoutek 1973 XII on plates taken with the Curtis Schmidt telescope of the University of Michigan at the Cerro Tololo Inter-American Observatory is described in detail. The formula for the determination of the air mass, and the correction for atmospheric absorption and for the loss of light due to vignetting are included. The calibration stars were used to derive the coefficients converting the relative intensity scale to the absolute surface-brightness units. The extensive results of the study of the orbital evolution of vaporizing dust particles are listed in a tabular form. Gradual evaporation from the surface of a particle results typically in its expulsion from the solar system. The properties of the particle and the elements of its orbit at expulsion are given as functions of the particle's properties and orbit before appreciable evaporation commenced. Also given are circumstances at an encounter of an expelled particle with the earth as a function of the particle's properties. A few specific cases are represented graphically.
Sekanina, Z.↗
Surface tension propellant acquisition system technology for Space Shuttle reaction control tanks
A program was conducted to provide the technology base for the SS/RCS flight tankage. Through a combination of analysis, subscale testing and computer predictions, a surface tension acquisition/expulsion system design was developed for the Orbiter RCS application. A full-scale tank system was fabricated and ground verification testing was conducted. Cleaning, inspection, fill and drain, and one-g expulsion performance were demonstrated. Results show that the fine-mesh screen, compartmented tank system provides the performance, flexibility, reusability, and other characteristics required by the pulsing, high flowrate RCS. It provides the required expulsion under widely differing high-g boost abort and reentry vectors oriented 119 deg apart and during on-orbit operation under omnidirectional low-g conditions.
Fester, D. A.↗
Magnetic control systems for large spacecraft with applications to space telescope
Magnetic control systems for large space vehicles offer the advantage of a simple, reliable, low cost augmentation to the primary control system. When used for momentum management, a magnetic torque source offers a long life and noncontaminant environment when compared to a mass expulsion torque source. These qualities make such systems suitable for employment with the Space Telescope, which is a long life, high performance vehicle with optics and scientific instruments which would be degraded by contamination due to mass expulsion products. The various applications of magnetic systems on the Space Telescope are considered. The future trend in magnetic control of large space vehicles lies in providing a known three axis reference for backup operations, such as recovery of the primary control mode.
Dougherty, H.↗
Cryogenic fluid management experiment
The cryogenic fluid management experiment (CFME), designed to characterize subcritical liquid hydrogen storage and expulsion in the low-q space environment, is discussed. The experiment utilizes a fine mesh screen fluid management device to accomplish gas-free liquid expulsion and a thermodynamic vent system to intercept heat leak and control tank pressure. The experiment design evolved from a single flight prototype to provision for a multimission (up to 7) capability. A detailed design of the CFME, a dynamic test article, and dedicated ground support equipment were generated. All materials and parts were identified, and components were selected and specifications prepared. Long lead titanium pressurant spheres and the flight tape recorder and ground reproduce unit were procured. Experiment integration with the shuttle orbiter, Spacelab, and KSC ground operations was coordinated with the appropriate NASA centers, and experiment interfaces were defined. Phase 1 ground and flight safety reviews were conducted. Costs were estimated for fabrication and assembly of the CFME, which will become the storage and supply tank for a cryogenic fluid management facility to investigate fluid management in space.
Eberhardt, R. N.↗
Cryogenic fluid management for low-g transfer
An account is given of design and operations criteria pertaining to low-g environment systems for the collection and delivery of liquid cryogens to a supply tank drain inlet in orbit. Analyses must assess the draining efficiencies of such devices, because the minimization of supply tank residual contents is of the essence. Settling accelerations, passive expulsion, and positive expulsion methods of fluid control have all been successfully demonstrated in orbit. Attention is given to the unique advantages and disadvantages of each method in view of different sets of requirements.
Frank, D. J.↗
Transport critical current and magnetization measurements of melt-processed YBa2Cu3O(7-x)
This paper reports on the magnetic field dependence of the transport critical current and dc magnetic susceptibility measurements on YBa2Cu3O(7-x) superconductors formed by melt-solid reactions at 950 C between Ba-Cu-O (or Tb-Ba-cu-O) and solid nonstoichiometric Y-Ba-Cu oxide. Four-probe dc critical current measurements at 77, 64, and 4.2 K show strong depression of the critical current density with increasing magnetic field, in agreement with a model of weakly linked superconducting regions. Diamagnetic shielding and Meissner flux expulsion measurements in the temperature range 10-300 K show about one-third volume fraction of perfect superconductivity. Both shielding and flux expulsion were observed to be approximately temperature independent below 60 K, indicating strong coupling between the grains throughout the entire volume below this temperature.
Hermann, A. H.↗
Results of low power deicer tests on a swept inlet component in the NASA Lewis icing research tunnel
Tests were conducted under a USAF/NASA Low Power Deicer program on two expulsive technologies to examine system performance on hardware representative of a modern aircraft part. The BF Goodrich Electro-Expulsive Deicing System and Pneumatic Impulse Ice Protection System were installed on a swept, compound curve, engine inlet component with varying leading edge radius, and tested through a range of icing and system operating conditions in the NASA Lewis Icing Research Tunnel. A description of the experimental procedure and results, including residual ice thickness, shed ice particle size, and changes in system energy/pressure characteristics are presented.
Bond, Thomas H.↗
Results of Low Power Deicer tests on a swept inlet component in the NASA Lewis Icing Research Tunnel
Tests were conducted under a USAF/NASA Low Power Deicer program on two expulsive technologies to examine system performance on hardware representative of a modern aircraft part. The BF Goodrich Electro-Expulsive Deicing System and Pneumatic Impulse Ice Protection system were installed on a swept, compound curve, engine inlet component with varying leading edge radius, and tested through a range of icing and system operating conditions in the NASA Lewis Icing Research Tunnel. A description of the experimental procedure and results, including residual ice thickness, shed ice particle size, and changes in system energy/pressure characteristics are presented.
Bond, Thomas H.↗
Fluid Acquisition and Resupply Experiment (FARE-I) flight results
The Fluid Acquisition and Resupply Experiment, (FARE) is a Shuttle middeck-mounted experiment to demonstrate techniques for handling liquids in zero gravity for operations such as refueling spacecraft in orbit. The first flight took place on STS 53 launched December 2, 1992. Eight tests were performed during the mission and the experiment achieved 100 percent mission success. The second flight will be on STS 57, scheduled for launch in June 1993. The objective of FARE I was to demonstrate techniques for controlling the position of the liquid and gas within a tank during refilling and to better understand the operation of screen-type surface tension devices used to drain tanks in zero gravity. Tests were performed to demonstrate tank refilling, low gravity propellant slosh, and expulsion efficiency of the screen device. Expulsion efficiencies of 97 percent - 98 percent were demonstrated under a variety of flowrates and accelerations. Final fill levels of 60 percent to 80 percent were achieved during the vented fill tests.
Dominick, Sam M.↗
Plume diagnostics of SRM static firings for pressure perturbation studies
During the shuttle launches, the solid rocket motors (SRM) occasionally experience pressure perturbations (8-13 psi) between 65 and 75 seconds into the motor burn time. The magnitudes of these perturbations are very small in comparison with the operating motor chamber pressure, which is over 600 psi during this time frame. These SRM pressure perturbations are believed to be caused primarily by the expulsion of slag (aluminum oxide). Two SRM static tests, TEM-11 and FSM-4, were instrumented extensive]y for the study of the phenomenon associated with pressure perturbations. The test instrumentation used included nonintrusive optical and infrared diagnostics of the plume, such as high-speed photography, radiometers, and thermal image cameras. Results from all these nonintrusive observations strongly support the scenario that the pressure perturbation event in the shuttle SRM is caused primarily by the expulsion of molten slag. The slag was also expelled preferentially near the bottom of the nozzle due to slag accumulation at the bottom of the aft end of the horizontally oriented motor.
Sambamurthi, J. K.↗
An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in the Space Shuttle Bay at LEO for the International Space Welding Experiment
In 1997, the United States [NASA] and the Paton Electric Welding Institute are scheduled to cooperate in a flight demonstration on the U.S. Space Shuttle to demonstrate the feasibility of welding in space for a possible repair option for the International Space Station Alpha. This endeavor, known as the International Space Welding Experiment (ISWE), will involve astronauts performing various welding exercises such as brazing, cutting, welding, and coating using an electron beam space welding system that was developed by the E.O. Paton Electric Welding Institute (PWI), Kiev Ukraine. This electron beam welding system known as the "Universal Weld System" consists of hand tools capable of brazing, cutting, autogeneous welding, and coating using an 8 kV (8000 volts) electron beam. The electron beam hand tools have also been developed by the Paton Welding Institute with greater capabilities than the original hand tool, including filler wire feeding, to be used with the Universal Weld System on the U.S. Space Shuttle Bay as part of ISWE. The hand tool(s) known as the Ukrainian Universal Hand [Electron Beam Welding] Tool (UHT) will be utilized for the ISWE Space Shuttle flight welding exercises to perform welding on various metal alloy samples. A total of 61 metal alloy samples, which include 304 stainless steel, Ti-6AI-4V, 2219 aluminum, and 5456 aluminum alloys, have been provided by NASA for the ISWE electron beam welding exercises using the UHT. These samples were chosen to replicate both the U.S. and Russian module materials. The ISWE requires extravehicular activity (EVA) of two astronauts to perform the space shuttle electron beam welding operations of the 61 alloy samples. This study was undertaken to determine if a hazard could exist with ISWE during the electron beam welding exercises in the Space Shuttle Bay using the Ukrainian Universal Weld System with the UHT. The safety issue has been raised with regard to molten metal detachments as a result of several possible causes such as welder procedural error, externally applied impulsive forces(s), filler wire entrainment and snap-out, cutting expulsion, and puddle expulsion. Molten metal detachment from either the weld/cut substrate or weld wire could present harm to a astronaut in the space environment it the detachment was ti burn through the fabric of the astronaut Extravehicular Mobility Unit (EMC). In this paper an experimental test was performed in a 4 ft. x 4 ft. vacuum chamber at MSFC enabling protective garment to be exposed to the molten metal drop detachments to over 12 inches. The chamber was evacuated to vacuum levels of at least 1 x 10(exp -5) torr (50 micro-torr) during operation of the 1.0 kW Universal Hand Tool (UHT). The UHT was manually operated at the power mode appropriate for each material and thickness. The space suit protective welding garment, made of Teflon fabric (10 oz. per yard) with a plain weave, was placed on the floor of the vacuum chamber to catch the molten metal drop detachments. A pendulum release mechanism consisting of four hammers, each weighing approximately 3.65 lbs, was used to apply an impact forces to the weld sample/plate during both the electron beam welding and cutting exercises. Measurements were made of the horizontal fling distances of the detached molten metal drops. The volume of a molten metal drop can also be estimated from the size of the cut. Utilizing equations, calculations were made to determine chande in surafec area (Delat a(surface)) for 304 stainless steel for cutting based on measurements of metal drop sizes at the cut edges. For the cut sample of 304 stainless steel based on measurement of the drop size at the edge, Delta-a(surface) was determined to be 0.0054 2 in . Calculations have indicated only a small amount of energy is required to detach a liquid metal drop. For example, approximately only 0.000005 ft-lb of energy is necessary to detach a liquid metal steel drop based on the above theoretical analysis. However, some of the energy will be absorbed by the plate before it reaches the metal drop. Based on the theoretical calculations, it was determined that during a weld cutting exercise, the titanium alloy would be the most difficult to detach molten metal droplets followed by stainless steel and then by aluminum. The results of the experimental effort have shown that molten metal will detach if large enough of a hammer blow is applied to the weld sample plate during the full penetration welding and cutting exercises. However, no molten metal detachments occurred as a result of the filler wire snap-out tests from the weld puddle since it was too difficult to cause the metal to flick-out from the pool. Molten metal detachments, though not large in size, did result from the direct application of the electron beam on the end of the filler weld wire.
Fragomeni, James M.↗
Numerical Modeling of Pressurization of a Propellant Tank
An unsteady finite volume procedure has been developed to predict the history of pressure, temperature and mass flow rate of the pressurant and propellant during the expulsion of the propellant from a tank. The time dependent mass, momentum and energy conservation equations are solved at the ullage space. The model accounts for the change in the ullage volume due to expulsion of the propellant. It also accounts for the heat transfer from the tank wall and propellant to the ullage gas. The procedure was incorporated in the Generalized Fluid System Simulation Program (GFSSP). The results of several test cases were then compared with a published correlation of pressurant requirements for a given displacement of propellant. The agreement between the predictions and the correlation was found to be satisfactory.
Majumdar, Alok↗
Numerical Modeling of Pressurization of a Propellant Tank
An unsteady finite volume procedure has been developed to predict the history o pressure, temperature and mass flow rate of the pressurant and propellant during the expulsion of the propellant from a tan. The time dependent mass, momentum and energy conservation equations are solved at the ullage space. The model accounts for the change in the ullage volume due to expulsion of the propellant. It also accounts for the heat transfer from the tank wall and propellant to the ullage gas. The procedure was incorporated in the Generalized Fluid System Simulation Program (GFSSP). The results of several test cases were then compared with a published correlation of pressurant requirements for a given displacement of propellant. The agreement between the predictions and the correlation was found to be satisfactory.
Majumdar, Alok↗
Material Outflows from Coronal Intensity "Dimming Regions" during Coronal Mass Ejection Onset
One signature of expulsion of coronal mass ejections (CMEs) from the solar corona is the appearance of transient intensity dimmings in coronal images. These dimmings have generally been assumed to be due to discharge of CME material from the corona, and thus the 'dimming regions' are thought of as an important signature of the sources of CMEs. We present spectral observations of two dimming regions at the time of expulsion of CMEs, using the Coronal Diagnostic Spectrometer (CDS) on the SOHO satellite. One of the dimming regions is at the solar limb and associated with a CME traveling in the plane of the sky, while the other region is on the solar disk and associated with an Earth-directed 'halo' CME. From the limb event, we see Doppler signatures of approximately 30 km/s in coronal (Fe XVI and Mg IX) emission lines, where the enhanced velocities coincide with the locations of coronal dimming. This provides direct evidence that the dimmings are associated with outflowing material. We also see larger (approximately 100 km/s) Doppler velocities in transition region (O V and He I) emission lines, which are likely to be associated with motions of a prominence and loops at transition region temperatures. An 'EIT wave' accompanies the disk event, and a dimming region behind the wave shows strong blueshifted Doppler signatures of approximately 100 km/s in O V, suggesting that material from the dimming regions behind the wave may be feeding the CME.
Harra, Louise K.↗
Material Outflows from Coronal Intensity "Dimming Regions" During Coronal Mass Ejection Onset
One signature of expulsion of coronal mass ejections (CMEs) from the solar corona is the appearance of transient intensity dimmings in coronal images. These dimmings have generally been assumed to be due to discharge of CME material from the corona, and thus the "dimming regions" are thought of as an important signature of the sources of CMEs. We present spectral observations of two dimming regions at the time of expulsion of CMEs, using the Coronal Diagnostic Spectrometer (CDS) on the SOHO satellite. One of the dimming regions is at the solar limb and associated with a CME traveling in the plane of the sky, while the other region is on the solar disk and associated with an Earth-directed "halo" CME. From the limb event, we see Doppler signatures of approximately equal to 30 kilometers per second in coronal (Fe XVI and Mg Ix) emission lines, where the enhanced velocities coincide with the locations of coronal dimming. This provides direct evidence that the dimmings are associated with outflowing material. We also see larger (approximately equal to 100 kilometers per second). Doppler velocities in transition region (0 v and He I) emission lines, which are likely to be associated with motions of a prominence and loops at transition region temperatures. An "EIT wave" accompanies the disk event, and a dimming region behind the wave shows strong blue-shifted Doppler signatures of approximately equal to 100 kilometers per second in 0 v, suggesting that material from the dimming regions behind the wave may be feeding the CME.
Harra, Louise K.↗