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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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Thermal performance of self evacuated multilayer radiation shield insulation of lightweight prefabricated panels for space vehicle cryogenic propellant tanks
Vacuum multilayer insulation for cryogenic space propulsion vehicles noting self-evacuation system and calorimetric test
Evaluation of self-evacuating multilayer radiation shields for cryogenic storage tanks
Space evacuation of NRC-2 insulation for liquid hydrogen tankage, noting vacuum test apparatus and cold plate test
Gas pressure differential across multilayer insulation blanket during rapid evacuation predicted, using one dimensional flow theory
Multilayer insulation of prefabricated panels is developed for cryogenic storage tanks. System utilizes panels of aluminized Mylar separated by sheets of low conductivity polyurethane foam. Panels are self-evacuated by cryopumping of gaseous carbon dioxide at time of use.
Gas pressure differential across multilayer insulation blanket during rapid evacuation predicted, using one dimensional flow theory
The elements in the evacuated multilayer insulation system were investigated, and the major weight contributors for optimization selected. Outgassing tests were conducted on candidate vacuum jacket materials and experiments were conducted to determine the vacuum and structural integrity of selected vacuum jacket configurations. A nondestructive proof test method, applicable to externally pressurized shells, was validated on this program.
A process of molding long thin-wall tubular bodies from thermosetting plastic molding compounds is described wherein the tubular body lengths may be several times the diameters. The process is accomplished by loading a predetermined quantity of molding compound into a female mold cavity closed at one end by a force mandrel. After closing the other end of the female mold with a balance mandrel, the loaded cavity is evacuated by applying a vacuum of from one-to-five mm pressure for a period of fifteen-to-thirty minutes. The mold temperature is raised to the minimum temperature at which the resin constituent of the compound will soften or plasticize and a pressure of 2500 psi is applied.
Compression-molding process conprises: loading molding compound; evacuation; applying pressure to shape softened compound; further compressing while using compound as hydraulic fluid; and applying heat and pressure for cure. Major advantage of method is that it prevents increase in cavity volume (sporadic or general) throughout transformation phase of molding.
A high-performance collector based on the use of all-glass, evacuated tubular collector elements is described and analyzed, and supporting experimental data presented. The collector operated with excellent efficiency at temperatures high enough to drive existing air conditioning units, and showed good performance under diffuse light and low insolation conditions. Collector efficiency was insensitive to operating temperature, ambient temperature, and wind speed. In addition, air, as well as liquid, can be used as the heat transfer fluid, with no significant performance penalty. While the equations governing the useful energy produced can be cast in a form similar to that for flat plate collectors, several important parameters were unique in a number of respects. The loss coefficient was unusually low, while the flow factor and effective insolation were unusually high.
According to report, particular commercial evacuated-tube solar collector performs slightly more efficiently with larger manifold. Tests were performed with Marshall Space Flight Center solar simulator. Report describes test conditions and procedures, provides analysis of results, and presents tables and graphs of data, both measured and calculated.
An evaluation of all day efficiency for selected flat plate and evacuated tube collectors is presented. Computations are based on a modified version of the NBSIR 78-1305A procedure for all day efficiency. The ASHMET and NOAA data bases for solar insolation are discussed. Details of the algorithm used to convert total (global) horizontal radiation to the collector tilt plane of the selected sites are given along with tables and graphs which show the results of the tests performed during this evaluation.
Emergency egress system allows people to be evacuated quickly from tall structures. New emergency system applicable to rescues from fires in tall hotels and other buildings. System consists of basket on slide wire. Basket descends by gravity on sloped slide wire staked to ground.
A computer model is described to study strategies used by passengers evacuating a burning aircraft. Two baseline cases are presented to demonstrate the model. In the first case, in a simple scenario, strategies were found to change from even movement to the nearest exit to others farthest from the fire. In the second case, a test studying the effects of obstacles on passenger movement, nonlinear effects were found that may increase the time required to escape. The presence of obstacles created bottlenecks and, in some cases, isolated whole sections of the passenger cabin, making it impossible to escape. This occurred even though exits were still available for escape, but passengers could not reach them.
An experimental investigation was conducted in the slotted test section of the 0.1-scale model of the proposed Altitude Wind Tunnel to evaluate wall interference effects at tunnel Mach numbers from 0.70 to 0.95 on bodies of revolution with blockage rates of 0.43, 3, 6, and 12 percent. The amount of flow that had to be removed from the plenum chamber (which surrounded the slotted test section) by the plenum evacuation system (PES) to eliminate wall interference effects was determined. The effectiveness of tunnel reentry flaps in removing flow from the plenum chamber was examined. The 0.43-percent blockage model was the only one free of wall interference effects with no PES flow. Surface pressures on the forward part of the other models were greater than interference-free results and were not influenced by PES flow. Interference-free results were achieved on the aft part of the 3- and 6-percent blockage models with the proper amount of PES flow. The required PES flow was substantially reduced by opening the reentry flaps.
The invention is an adjustable mount for positioning an electro-optic transducer in an evacuated cryogenic environment. Electro-optic transducers are used in this manner as high sensitivity detectors of gas emission lines of spectroscopic analysis. The mount is made up of an adjusting mechanism and a transducer mount. The adjusting mechanism provided five degrees of freedom, linear adjustments and angular adjustments. The mount allows the use of an internal lens to focus energy on the transducer element thereby improving the efficiency of the detection device. Further, the transducer mount, although attached to the adjusting mechanism, is isolated thermally such that a cryogenic environment can be maintained at the transducer while the adjusting mechanism remains at room temperature. Radiation shields also are incorporated to further reduce heat flow to the transducer location.
The Safety Assessment for Flight Evacuation (SAFE) system has been developed for the computerized evaluation of safety in civil Emergency Medical Service (EMS) operations. The speed of the microprocessor used to analyze data allows many individual factors to be considered, as well as the interactions among those factors. SAFE's data base is structured as if-then conditional statements. SAFE also allows the most important of the factors to be given greater weight in the final score. The questionnaire filled by EMS crews encompassed mission-, crew-, organization-, environment-, and aircraft-related factors; each of these was subdivided into as many as eight variables affecting the EMS-mission risk of that factor.