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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Hydrophobic, Thermal Shock-and-Corrosion-Resistant XSBR Latex-Modified Lightweight Class G Cement Composites in Geothermal Well Energy Storage Systems

Energy losses can be significantly reduced if thermally insulating cement is used for energy storage and recovery. The thermal conductivity (TC) of the currently used cement is between 1 and 1.2 W/mK. In this study we assessed the ability of polystyrene (PS)–polybutadiene (PB)–polyacrylic acid (PAA) terpolymer (cross-linked styrene–butadiene rubber, XSBR) latex to improve thermal insulating properties and thermal shock (TS) resistance of class G ordinary Portland cement (OPC) and fly ash cenosphere (FCSs) composites in the temperature range of 100–175 °C. The composites autoclaved at 100 °C were subjected to three cycles, one cycle: 175 °C heat → 25 °C water quenching). In hydrothermal and thermal (TS) environments at elevated temperatures in cement slurries the XSBR latex formed acrylic calcium complexes through acid–base reactions, and the number of such complexes increased at higher temperatures due to the XSBR degradation with formation of additional acrylic groups. As a result, these complexes offered the following five advanced properties to the OPC-based composites: (1) enhanced hydrophobicity; (2) decreased water-fillable porosity; (3) reduced TC for water-saturated composites; (4) minimized loss of compressive strength, Young’s modulus, and compressive fracture toughness after TS; and (5) abated pozzolanic activity of FCSs, which allowed FCSs to persist as thermal insulators under strongly alkaline conditions of cement slurries. Additionally, XSBR-modified slurries possessed improved workability and decreased slurry density due to the air-entraining effect of latex, which resulted in further improvement of thermal insulation performance of the modified composites.

15 GEOTHERMAL ENERGY↗
NASA NTRS1972

Thermal/structural optimization of cryogenic storage systems.

An analytical method has been developed to optimize a cryogenic storage system designed for long term storage of cryogenic propellants. The type of propellant, mission duration, thermal environment, insulation thermal properties, insulation vent time, and the storage system weight penalty imposed by the design pressure were considered as the dependent parameters. The optimum system insulation thickness and vent pressure were then calculated in terms of these parameters. The method was applied to the design of the Space Shuttle Orbiter oxygen and hydrogen tanks to obtain an optimum design. It was determined that for the mission examined, the hydrogen tank optimum design was close to the initial pressure. A continuously vented hydrogen tank, therefore, was close to the optimum design. Also, it was determined that for this particular mission the oxygen tank should not be vented.

Navickas, J.↗
DOE OSTI2023

Final Technical Report

The project goal is to demonstrate low-cost, interlocking, and carbon-storing insulation materials with thermal insulation of R5/inch, flexural modulus > 10 MPa, low material price < $ 0.5/ft2 wall area (materials cost for ½” thick panel), and net embodied carbon of 0.8t net CO2e/t (60% reduction compared to gypsum), respectively, which can meet the cost and performance targets of department of energy (DOE)’s 2050 climate target. To achieve this goal, the project plans three tasks, and each has a specific objective: 1) Modular design and engineering analysis of interlocking insulation panel blocks using biogenic materials (cellulose, straw, etc.): with the consideration of potential assembling and recycling. 2) Scalable manufacturing of biogenic-based interlocking insulation panels: scale up the modular panel production using ambient pressure drying and surface superhydrophobic modification at 1ft*1ft with the potential for further scalable mass production of 4ft*4ft. 3) Code-compliant testing, recycling and carbon footprint analysis of manufactured interlocking insulation panels examined using ASTM standards of thermal insulation (ASTM C518), mechanical properties (ASTM C1161), and water vapor transmission (ASTM E96).

Ren, Shenqiang↗
NASA NTRS2013

Composite Aerogel Multifoil Protective Shielding

New technologies are needed to survive the temperatures, radiation, and hypervelocity particles that exploration spacecraft encounter. Multilayer insulations (MLIs) have been used on many spacecraft as thermal insulation. Other materials and composites have been used as micrometeorite shielding or radiation shielding. However, no material composite has been developed and employed as a combined thermal insulation, micrometeorite, and radiation shielding. By replacing the scrims that have been used to separate the foil layers in MLIs with various aerogels, and by using a variety of different metal foils, the overall protective performance of MLIs can be greatly expanded to act as thermal insulation, radiation shielding, and hypervelocity particle shielding. Aerogels are highly porous, low-density solids that are produced by the gelation of metal alkoxides and supercritical drying. Aerogels have been flown in NASA missions as a hypervelocity particle capture medium (Stardust) and as thermal insulation (2003 MER). Composite aerogel multifoil protective shielding would be used to provide thermal insulation, while also shielding spacecraft or components from radiation and hypervelocity particle impacts. Multiple layers of foil separated by aerogel would act as a thermal barrier by preventing the transport of heat energy through the composite. The silica aerogel would act as a convective and conductive thermal barrier, while the titania powder and metal foils would absorb and reflect the radiative heat. It would also capture small hypervelocity particles, such as micrometeorites, since it would be a stuffed, multi-shock Whipple shield. The metal foil layers would slow and break up the impacting particles, while the aerogel layers would convert the kinetic energy of the particles to thermal and mechanical energy and stop the particles.

Jones, Steven M.↗
DOE OSTI2020

Porous architecture and thermal properties of thermal barrier coatings deposited by suspension plasma spray

Besides the intrinsic low heat transfer capability of material, the thermal insulation property of thermal barrier coatings (TBCs) also relies on their microstructures. For better understanding the relationship between process parameters, porous architecture, and thermal properties of coatings, YSZ coatings were firstly manufactured by suspension plasma spray (SPS). Afterwards their total porosities were characterized by using the technique of X-ray transmission, the nano/submicro pores in those coatings were detected with Ultra-Small Angle X-ray Scattering (USAXS), and the thermal properties of coatings were measured using the laser flash method. The results indicated that: i) the porous architecture of SPS coatings can be tailored by adapting process parameters. ii) increasing total porosity is an effective means for reducing the heat transfer capability of SPS coatings. iii) nano/submicro pores have higher influence sensitivity on thermal properties than that of larger pores. Increasing the content of nano-submicro pores is therefore more effective for improving the thermal insulation property of SPS coatings. The potential of SPS technique for fabricating TBCs was discussed as well.

36 MATERIALS SCIENCE↗
NASA NTRS1978

Life test results for an ensemble of CO2 lasers

The effects of cathode material, cathode operating temperature, anode configuration, window materials, and hydrogen additives on laser lifetime are determined. Internally oxidized copper and silber-copper alloy cathodes were tested. The cathode operating temperature was raised in some tubes through the use of thermal insulation. Lasers incorporating thermally insulated silver copper oxide cathodes clearly yielded the longest lifetimes-typically in excess of 22,000 hours. The use of platinum sheet versus platinum pin anodes had no observable effect on laser lifetime. Similarly, the choice of germanium, cadmium telluride, or zinc selenide as the optical window material appears to have no impact on lifetime.

Peruso, C. J.↗
NASA NTRS2001

The Evolution of Flexible Insulation as Thermal Protection Systems for Reusable Launch Vehicles: AFRSI (Advanced Flexible Reusable Surface Insulation) to CRI (Conformal Reusable Insulation)

This viewgraph presentation gives an overview of the evolution of flexible insulation as a thermal protection system for reusable launch vehicles, Advanced Flexible Reusable Surface Insulation (AFRSI) to Conformal Reusable Insulation (CRI). Details are given on the approved use of AFRIS on the Shuttle Orbiter in June 1980, the first flight of AFRIS on STS-6, windward blanket development, composite flexible blanket insulation, and flight demonstrations.

Rezin, Marc↗
DOE OSTI2023

Computational design of isotropic and anisotropic ultralow thermal conductivity polymer foams

Current state-of-the-art commercial polymer thermal insulation foam exhibits a thermal conductivity of 24 mW·m -1 ·K -1 (equivalently thermal resistivity of R-6/in.), similar to that of static air. To further optimize building energy efficiency, achieving even lower thermal conductivity is needed, which is, however, highly challenging. This paper presents computational evidence that demonstrates the feasibility of achieving an ultra-low thermal conductivity of less than 14.4 mW·m -1 ·K -1 (equivalently R-10/in.) using isotropic and anisotropic foam cell designs. For the isotropic design, we have identified analytical effective medium approximation (EMA) models within the accuracy of ±5% as finite element analysis (FEA) in predicting the effective thermal conductivity of foams with various porosities and filler gases. For the anisotropic design, we have developed and validated new EMA models against FEA in predicting the effective thermal conductivity of general anisotropic cuboids and Voronoi foams. For both isotropic and anisotropic designs, the design spaces for 18, 16, and 14.4 mW·m -1 ·K -1 (equivalently R-8, R-9 and R-10/in.) using various filler gases are obtained. It is found that polymer foams can be improved to achieve ultralow thermal conductivity by reducing CO 2 concentration, reducing radiation, increasing porosity, and using anisotropic pore geometry. In conclusion, these findings contribute to the development of highly efficient thermal insulation materials, enhancing building energy efficiency and promoting sustainable construction practices.

42 ENGINEERING↗
NASA NTRS1991

Composite flexible insulation for thermal protection of space vehicles

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the aeroassist space transfer vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.↗
NASA NTRS1992

Composite flexible insulation for thermal protection of space vehicles

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the aeroassist space transfer vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.↗
NASA NTRS1992

Composite flexible insulation for thermal protection of space vehicles

A composite flexible blanket insulation (CFBI) system considered for use as a thermal protection system for space vehicles is described. This flexible composite insulation system consists of an outer layer of silicon carbide fabric, followed by alumina mat insulation, and alternating layers of aluminized polyimide film and aluminoborosilicate scrim fabric. A potential application of this composite insulation would be as a thermal protection system for the aerobrake of the Aeroassist Space Transfer Vehicle (ASTV). It would also apply to other space vehicles subject to high convective and radiative heating during atmospheric entry. The thermal performance of this composite insulation as exposed to a simulated atmospheric entry environment in a plasma arc test facility is described. Other thermophysical properties which affect the thermal response of this system are also described. Analytical modeling describing the thermal performance of this composite insulation is included. It shows that this composite insulation is effective as a thermal protection system at total heating rates up to 30.6 W/sq cm.

Kourtides, Demetrius A.↗
NASA NTRS2000

How Will We Keep Warm on the Red Planet?

Among the many challenges that the Mars environment poses for EVA (extravehicular activity) space suit designers, development of an appropriate thermal insulation is one of the most important. The latest in thermal insulation technologies that could be applied or modified for planetary exploration have been reviewed. These include porous and hollow structures, phase change materials, soluble gas elements, as well as vacuum enclosures and fibrous materials. Using current technology, none of these structures offers all of the features needed for Mars exploration, namely lightweight, low bulk, high flexibility, and low thermal insulation. Nonwoven fibrous materials are still the prime design candidates because they are more flexible than other structures while having good resiliency. They are usually safe to use. They are also available in many types of materials, fiber shapes, as well as fabric densities and constructions. However, a recent study conducted at the NASA Johnson Space Center shows clearly that these structures alone are not sufficient to provide effective thermal insulation in the harsh Mars environment. A more promising solution is being developed using aerogel fillers in the nonwoven structures.

Orndoff, Evelyne↗
DOE OSTI2024

Flame-retardant cellulose-aerogel composite from agriculture waste for building insulation

Bio-based thermal insulation materials are in high demand due to their availability, reproducibility, and carbon-sequestration nature. However, high flammability, moisture condensation, and high thermal conductivity of biogenic material are major concerns for sustainable building applications. In this study, we report the fire-retardant cellulose aerogel insulation nanocomposites derived from wheat straw and silica aerogel, in which sodium bicarbonate improves its fire retardancy. We combined blended straw fibers and hammermilled straw fibers to create a structural hierarchy composite. The blended straw, with its longer and thicker size, served as reinforcement, while the hammermilled straw fibers acted as filler. This hierarchical structure was further integrated with aerogel for applications in green buildings. The as-prepared materials show a low thermal conductivity of 24.1 mW/m.K, high flexural modulus of 736 MPa, hydrophobicity with a water contact angle of 110.42°, and excellent fire retardancy. Altogether, this work provides an effective method for the synthesis of fire-retardant biogenic thermal insulation materials and shows a promising way for next-generation bio-based insulation materials.

36 MATERIALS SCIENCE↗
NASA NTRS2004

Epoxy Crosslinked Silica Aerogels (X-Aerogels)

NASA is interested in the development of strong lightweight materials for the dual role of thermal insulator and structural component for space vehicles; freeing more weight for useful payloads. Aerogels are very-low density materials (0.010 to 0.5 g/cc) that, due to high porosity (meso- and microporosity), can be, depending on the chemical nature of the network, ideal thermal insulators (thermal conductivity approx. 15 mW/mK). However, aerogels are extremely fragile. For practical application of aerogels, one must increase strength without compromising the physical properties attributed to low density. This has been achieved by templated growth of an epoxy polymer layer that crosslinks the "pearl necklace" network of nanoparticles: the framework of a typical silica aerogel. The requirement for conformal accumulation of the epoxy crosslinker is reaction both with the surface of silica and with itself. After cross-linking, the strength of a typical aerogel monolith increases by a factor of 200, in the expense of only a 2-fold increase in density. Strength is increased further by coupling residual unreacted epoxides with diamine.

fabrizio, Eve↗
NASA NTRS2003

Eroding Potentiometers

Eroding potentiometers have been devised for measuring the time-dependent positions of char fronts advancing through layers of insulating material subject to intense heating from one side. In the original application, the material layers of interest are thermal insulators in rocket motors and the heat comes from firing of the motors, but the principle of operation is equally applicable to other insulating materials subject to intense heating (e.g., ablative fire-retardant materials). Measuring the thickness decrement of propellant (in hybrid motors in particular) is another possible application of this transducer. Telemetry informs mission control of the propellant left after each burn. An eroding potentiometer could be characterized, more precisely, as an eroding two-wire resistor. It includes a twisted pair of thin, insulated wires oriented along the thickness of, and embedded in, the layer of thermal-insulation material to be tested (see figure). The electrical insulation material on the wires should be one for which the charring temperature is about the same as (or perhaps slightly less than) that of the thermal- insulation material to be tested. In the original rocket-motor application, the wires have a diameter of 0.003 in. (.0.08 mm), are made of manganin, and are coated with polyimide for electrical insulation. Outside the thermal insulation on the cold side, the wire leads are connected to a Wheatstone bridge circuit for measurement of electrical resistance change.

Eggett, Mark↗
NASA NTRS1959

Elevated-Temperature Tests Under Static and Aerodynamic Conditions on Corrugated-Stiffened Panels

Thermal-insulating panels made of 0.005-inch-thick corrugated-stiffened sheets of Inconel X, backed by either bulk or reflective insulation, were tested under static and aerodynamic conditions at elevated temperatures up to 1,8000 F in front of a quartz-tube radiant heater and in a blowdown wind tunnel at a Mach number of 1.4. The tests were performed to provide information on the structural integrity and insulating effectiveness of thermal-insulating panels under the effects of aerodynamic heating. Static radiant-heating tests showed that the bulk insulation protected a load-carrying structure better than did the reflective insulation; however, the bulk insulation was much heavier than the reflective insulation and made the panel assemblies about three times as thick. Three of the four panels tested in the heated supersonic wind tunnel fluttered and failed dynamically. However, one panel demonstrated that flutter can be alleviated considerably with proper edge support. The panels deflected toward the heater (or into the airstream) at a rate which was primarily dependent on the temperature difference through the panel thickness.

Groen, Joseph M.↗