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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS2001

Fundamental Boiling and RP-1 Freezing Experiments

This paper describes results from experiments performed to help understand certain aspects of the MC-1 engine prestart thermal conditioning procedure. The procedure was constrained by the fact that the engine must chill long enough to get quality LOX at the LOX pump inlet but must be short enough to prevent freezing of RP-1 in the fuel pump. A chill test of an MC-1 LOX impeller was performed in LN2 to obtain data on film boiling, transition boiling and impeller temperature histories. The transition boiling data was important to the chill time so a subsequent experiment was performed chilling simple steel plates in LOX to obtain similar data for LOX. To address the fuel freezing concern, two experiments were performed. First, fuel was frozen in a tray and its physical characteristics were observed and temperatures of the fuel were measured. The result was physical characteristics as a function of temperature. Second was an attempt to measure the frozen thickness of RP-1 on a cold wall submerged in warm RP-1 and to develop a method for calculating that thickness for other conditions.

Goode, Brian↗
NASA NTRS2007

Continuously Regenerable Freeze-Out CO2 Control Technology

Carbon dioxide (CO2) removal technology development for portable life support systems (PLSS) has traditionally concentrated in the areas of solid and liquid chemical sorbents and semi-permeable membranes. Most of these systems are too heavy in gravity environments, require prohibitive amounts of consumables for operation on long term planetary missions, or are inoperable on the surface of Mars due to the presence of a CO2 atmosphere. This paper describes the effort performed to mature an innovative CO2 removal technology that meets NASA s planetary mission needs while adhering to the important guiding principles of simplicity, reliability, and operability. A breadboard cryogenic carbon dioxide scrubber (Cryo Scrubber) for a closed loop cryogenic PLSS was developed, designed, and tested, and a conceptual design suitable for a PLSS was developed based on the results of the breadboard testing. The Cryo Scrubber freezes CO2 and other trace contaminants out of expired vent loop gas using cooling available from a liquid oxygen (LOX) based PLSS. The device is continuously regenerable, with solid CO2 being removed from the cold freeze-out surfaces, sublimated, and vented overboard. Duration is limited only by the supply of LOX stored in the PLSS. Simplicity, reliability, and operability are universally important criteria for critical hardware on long duration Lunar or Mars missions. The Cryo Scrubber has no moving parts, requires no additional consumables, and uses no electrical power, contributing to its simplicity and reliability. It is easy to use; no operator action is required to prepare, use, or shut down the Cryo Scrubber, and it does not require charging or regeneration. The versatility of the concept allows for operation on earth, the moon, and Mars, and in microgravity.

Fricker, John↗
NASA NTRS1996

Control of crystal growth in water purification by directional freeze crystallization

A Directional Freeze Crystallization system employs an indirect contact heat exchanger to freeze a fraction of liquid to be purified. The unfrozen fraction is drained away and the purified frozen fraction is melted. The heat exchanger must be designed in accordance with a Growth Habit Index to achieve efficient separation of contaminants. If gases are dissolved in the liquid, the system must be pressurized.

Conlon, William M.↗
NASA NTRS2018

Freeze Casting of LAGP for 3D Textured Solid-State Structural Electrolytes

In this study, all-solid-state structural lithium-ion batteries, a type of load bearing electrochemical energy storage that provides systems-level weight savings is being pursued for the realization of inherently safe next generation hybrid-electric and all-electric green aerospace propulsion systems. Currently investigated all-solid-state batteries do not meet the requirements for specific power and mechanical stability. To address these issues, freeze casting of lithium aluminum germanium phosphate (LAGP) electrolyte material has been explored for the creation of a textured 3D electrolyte scaffold with large interfacial surface area for high power discharge and hierarchical porosity for accommodation of active material volume changes during electrochemical cycling. We report the effects of freeze casting processing parameters on the microstructural development and mechanical performance of the scaffolds, characterized through scanning electron microscopy and ring-on-ring mechanical testing. Slurry composition and casting parameters such as solids loading, casting speed, tape angle, and temperature gradients have been modified to determine the impact on density, lamellar morphology, and final load-bearing performance.

ceramics↗
NASA NTRS2018

Experimental Effervescence and Freezing Point Depression Measurements of Nitrogen in Liquid Methane-Ethane Mixtures

NASA is designing an unmanned submarine to explore the depths of the hydrocarbon-rich seas on Saturn's moon Titan. Data from Cassini indicates that the Titan north polar environment sustains stable seas of variable concentrations of ethane, methane, and nitrogen, with a surface temperature near 93 K. The submarine must operate autonomously, study atmosphere/sea exchange, interact with the seabed, hover at the surface or any depth within the sea, and be capable of tolerating variable hydrocarbon compositions. Currently, the main thermal design concern is the effect of effervescence on submarine operation, which affects the ballast system, science instruments, and propellers. Twelve effervescence measurements on various liquid methane-ethane compositions with dissolved gaseous nitrogen are thus presented from 1.5 bar to 4.5 bar at temperatures from 92 K to 96 K to simulate the conditions of the seas. After conducting effervescence measurements, two freezing point depression measurements were conducted. The freezing liquid line was depressed more than 15 K below the triple point temperatures of pure ethane (90.4 K) and pure methane (90.7 K). Experimental effervescence measurements will be used to compare directly with effervescence modeling to determine if changes are required in the design of the thermal management system as well as the propellers.

Submarine↗
NASA NTRSDate not supplied

Experimental Observations of Mechanisms of Pattern Formation During Freeze Casting

Empirically, many different materials compositions have been freeze cast over the years. Few have been analyzed to better understand the mechanisms by which the ice crystal growth drives structure formation, particularly the substructures on the cell walls. Collating substructural features, for example, ridges, bridges, and “jellyfish-like” substructures, found on the cell walls of freeze-cast ceramics (platelets versus particles), fibrillated biopolymers (collagen, nanocellulose), and "smooth" biopolymers (chitosan, trehalose), we capture the ice crystal growth process and analyze it both in situ in 2D and "post-mortem" in 3D to gain insights into anisotropic ice crystal growth and other self-assembly mechanisms. Combining these experimental observations with 3D Phase-field simulations of structure formation in ice-templated materials, detailed in a companion presentation, it becomes possible to gain fundamental science insights and to obtain the desired structure-property-processing correlations not only at the more traditional macroscopic, but also at the meso- and microscopic scales.

Kaiyang Yin↗
NASA NTRSDate not supplied

Experimental Observations of Mechanisms of Pattern Formation During Freeze Casting

Empirically, many different materials compositions have been freeze cast over the years. Few have been analyzed to better understand the mechanisms by which the ice crystal growth drives structure formation, particularly the substructures on the cell walls. Collating substructural features, for example, ridges, bridges, and “jellyfish-like” substructures, found on the cell walls of freeze-cast ceramics (platelets versus particles), fibrillated biopolymers (collagen, nanocellulose), and "smooth" biopolymers (chitosan, trehalose), we capture the ice crystal growth process and analyze it both in situ in 2D and "post-mortem" in 3D to gain insights into anisotropic ice crystal growth and other self-assembly mechanisms. Combining these experimental observations with 3D Phase-field simulations of structure formation in ice-templated materials, detailed in a companion presentation, it becomes possible to gain fundamental science insights and to obtain the desired structure-property-processing correlations not only at the more traditional macroscopic, but also at the meso- and microscopic scales.

Kaiyan Yin↗
NASA NTRSDate not supplied

Actively Controlled Louver for Human Spacecraft Radiator Ultraviolet (UV), Dust, and Freeze Protection

This paper examines the use of actively controlled louvers to attenuate UV and dust, as well as mitigate freezing concerns for human spacecraft radiators during Artemis missions. Artemis missions to the lunar orbit or surface will expose the radiators to high energy UV radiation and dust, which will degrade the radiator’s coating emissivity and consequently reduce heat rejection performance. In addition, subfreezing environmental temperatures during transit to lunar orbit and nighttime on lunar south pole can rupture coolant tubes, reduce heat rejection performance, and worst-case scenario result in a Loss of Mission (LOM). Louver technology would be a promising solution to maintaining radiator performance and integrity for Artemis missions, but heritage louvers are passively controlled. This technology needs maturing to active control, or motor actuation, to achieve faster thermal response times. Actively controlled louver design considerations are discussed in this paper. The analysis that follows shows actively controlled louvers can attenuate high energy UV radiation and dust, as well as protect the coolant from freezing.

Louver↗
NASA NTRS2023

Actively Controlled Louver for Human Spacecraft Radiator Ultraviolet (UV), Dust, and Freeze Protection

This paper examines the use of actively controlled louvers to attenuate UV and dust, as well as mitigate freezing concerns for human spacecraft radiators during Artemis missions. Artemis missions to the lunar orbit or surface will expose the radiators to high energy UV radiation and dust, which will degrade the radiator’s coating emissivity and consequently reduce heat rejection performance. In addition, subfreezing environmental temperatures during transit to lunar orbit and nighttime on lunar south pole can rupture coolant tubes, reduce heat rejection performance, and worst-case scenario result in a Loss of Mission (LOM). Louver technology would be a promising solution to maintaining radiator performance and integrity for Artemis missions, but heritage louvers are passively controlled. This technology needs maturing to active control, or motor actuation, to achieve faster thermal response times. Actively controlled louver design considerations are discussed in this paper. The analysis that follows shows actively controlled louvers can attenuate high energy UV radiation and dust, as well as protect the coolant from freezing.

Louver↗
NASA NTRS1992

The effect of in situ freezing on rabbit patellar tendon. A histologic, biochemical, and biomechanical analysis

Cell necrosis has been well documented as one of the many changes that occur in autogenous tendon when it is used to reconstruct the anterior cruciate ligament. The purpose of this experiment was to isolate cell necrosis as a variable and study its effect on the patellar tendon. To accomplish this, both knees of 25 New Zealand White rabbits were operated on. In one knee, a 5-mm wide band of patellar tendon was subjected to two rapid freeze-thaw cycles, while the other knee underwent sham surgery. Histologic evaluation showed a zone of necrosis at 2 and 4 weeks with cellular repopulation complete at 8 weeks. patellar tendon cross-sectional area was 0.118 cm2 at 8 weeks for the frozen specimens compared to 0.102 cm2 for the sham-operated controls. This difference was significant at the P = 0.025 level. Mechanical testing at 4 and 8 weeks revealed no significant changes in tendon length, maximum load, or stiffness. The collagen content was also unchanged at both 4 and 8 weeks.

Non-NASA Center↗