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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 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Pressurization of a Flightweight, Liquid Hydrogen Tank: Evaporation and Condensation at a Liquid Vapor Interface

Evaporation and condensation at a liquid-vapor interface is important for long-term, in-space cryogenic propellant storage. Yet the current understanding of inter-facial physics does not consistently predict behavior of evaporation or condensation rates. The proposed paper will present a physical model, based on the 1-D Heat equation and Schrage's equation, which demonstrates thin thermal layers at the fluid vapor interface.

cryogenic hydrogen↗
NASA NTRS2018

An Initial Assessment of a SMAP Soil Moisture Disaggregation Scheme Using TIR Surface Evaporation Data over the Continental United States

The Soil Moisture Active Passive (SMAP) mission is dedicated toward global soil moisture mapping. Typically, an L-band microwave radiometer has spatial resolution on the order of 36-40 km, which is too coarse for many specific hydro-meteorological and agricultural applications. With the failure of the SMAP active radar within three months of becoming operational, an intermediate (9-km) and finer (3-km) scale soil moisture product solely from the SMAP mission is no longer possible. Therefore, the focus of this study is a disaggregation of the 36-km resolution SMAP passive-only surface soil moisture (SSM) using the Soil Evaporative Efficiency (SEE) approach to spatial scales of 3-km and 9-km. The SEE was computed using thermal-infrared (TIR) estimation of surface evaporation over Continental U.S. (CONUS). The disaggregation results were compared with the 3 months of SMAP-Active (SMAP-A) and Active/Passive (AP) products, while comparisons with SMAP-Enhanced (SMAP-E), SMAP-Passive (SMAP-P), as well as with more than 180 Soil Climate Analysis Network (SCAN) stations across CONUS were performed for a 19 month period. At the 9-km spatial scale, the TIR-Downscaled data correlated strongly with the SMAP-E SSM both spatially (r = 0.90) and temporally (r = 0.87). In comparison with SCAN observations, overall correlations of 0.49 and 0.47; bias of −0.022 and −0.019 and unbiased RMSD of 0.105 and 0.100 were found for SMAP-E and TIR-Downscaled SSM across the Continental U.S., respectively. At 3-km scale, TIR-Downscaled and SMAP-A had a mean temporal correlation of only 0.27. In terms of gain statistics, the highest percentage of SCAN sites with positive gains (>55%) was observed with the TIR-Downscaled SSM at 9-km. Overall, the TIR-based downscaled SSM showed strong correspondence with SMAP-E; compared to SCAN, and overall both SMAP-E and TIR-Downscaled performed similarly, however, gain statistics show that TIR-Downscaled SSM slightly outperformed SMAP-E.

Disaggregation↗
NASA NTRS2016

Development of the Auto-Fill Brine Evaporation Bag (BEB) System

The existing water recovery system on the International Space Station (ISS) is limited to 70 percent reclamation; consequently, long duration space missions are currently unfeasible due to the large quantity of water necessary to sustain the crew. The Brine Evaporation Bag (BEB) is a proposed system to supplement the existing water recovery system aboard the ISS and future deep space missions that can increase water recovery to 99 percent. The BEB project previously focused on the development of only the bag portion of the system. This paper focuses on the development of the BEB Evaporator. It will discuss the work to understand, optimize, and improve the entire BEB system while implementing a continuous-fill process. The results of that development and the advantages and limitations of the continuous-fill process will be presented.

Delzeit, Lance↗
NASA NTRSDate not supplied

Influence of evaporation rate and chamber pressure on the FUV reflectance and physical characteristics of aluminum films

Space telescopes for studying astrophysical phenomena from the far ultraviolet (FUV) to the near infrared (NIR) require durable mirror coatings with high and uniform reflectance over a very broad spectral region. While coatings for the optical and NIR region are well developed with proven performance, the FUV band presents significant challenges, particularly below 115 nm. Recent developments in physical vapor deposition (PVD) coating processes of aluminum mirrors that are protected with a metal-fluoride overcoat to prevent oxidation (such as LiF, MgF2, or AlF3) have improved reflectance in the FUV. While the emphasis in these studies has been placed on improving the deposition conditions of the metal-fluoride overcoats, less attention has been devoted to how deposition parameters (such as vacuum conditions or deposition rates) may affect the quality of the aluminum mirrors. This paper presents characterization of Al+MgF2 coupons made by flash evaporation of aluminum followed by resistive evaporation of MgF2. Samples were manufactured under a variety of processing conditions and the relationship between processing variables and mirror FUV reflectivity is analyzed. Performance characterization was based on the measured near-normal reflectance in the FUV (90-180 nm), and normal-incidence transmittance in the visible was done to analyze the possible presence of pinholes in the mirror. We demonstrated pinhole-free Al/MgF2 mirrors deposited at room temperature with a reflectivity of 0.91 at 122 nm wavelength. This reflectivity enhancement was achieved solely through parameter optimization.

Manuel A. Quijada↗
NASA NTRSDate not supplied

Influence of Evaporation Rate and Chamber Pressure on the FUV Reflectance and Physical Characteristics of Aluminum Films

Space telescopes for studying astrophysical phenomena from the far ultraviolet (FUV) to the near infrared (NIR) require durable mirror coatings with high and uniform reflectance over a very broad spectral region. While coatings for the optical and NIR region are well developed with proven performance, the FUV band presents significant challenges, particularly below 115 nm. Recent developments in physical vapor deposition (PVD) coating processes of aluminum mirrors that are protected with a metal-fluoride overcoat to prevent oxidation (such as LiF, MgF2, or AlF3) have improved reflectance in the FUV. While the emphasis in these studies has been placed on improving the deposition conditions of the metal-fluoride overcoats, less attention has been devoted to how deposition parameters (such as vacuum conditions or deposition rates) may affect the quality of the aluminum mirrors. This paper presents characterization of Al+MgF2 coupons made by flash evaporation of aluminum followed by resistive evaporation of MgF2. Samples were manufactured under a variety of processing conditions and the relationship between processing variables and mirror FUV reflectivity is analyzed. Performance characterization was based on the measured near-normal reflectance in the FUV (90-180 nm), and normal-incidence transmittance in the visible was done to analyze the possible presence of pinholes in the mirror. We demonstrated pinhole-free Al/MgF2 mirrors deposited at room temperature with a reflectivity of 0.91 at 122 nm wavelength. This reflectivity enhancement was achieved solely through parameter optimization.

FUV reflectance, aluminum, PVD, deposition rate, A↗
NASA NTRSDate not supplied

Lunar Passive Fuel Cell Technologies: Evaporator + Fluid Polishing Elements

This project investigates key elements of a fully-passive, fuel-cell based, surface power generation concept. The overall concept replaces the actively pumped thermal management of a state of the art (SOA) fuel cell/electrolyzer stack with a passive 2-phase thermosyphon for heat transport and a passive shape memory actuating radiator for temperature management. The elements of the concept investigated in this project are: Evaporator Element: Evaluating the compatibility of common fuel-cell interconnect materials in the evaporator of a 2-phase water thermosyphon Fluid Polishing element: The use of membrane gas separation and resin water polishing to address non-condensable gas removal and water purity.

Fuel Cell↗
DOE OSTI2024

Microfluidic film evaporation with femtosecond laser-patterned surface

Systems, apparatuses, and methods for microfluidic fluid evaporation using femtosecond laser-patterned surfaces are disclosed. A microfluidic device may comprise a femtosecond laser-patterned substrate having at least one input path and at least one output path. The femtosecond laser-patterned substrate may comprise both superhydrophobic and superhydrophilic sections. Fluid deposited at an input path may be wicked to an output path due to the surface pattern. A heating device may be provided to heat the fluid to evaporate volatiles therefrom. Vacuums and gas streams may be used to aid in volatile removal. Gas streams may add gas to the microfluidic device to react with the fluid.

Pearson, Connor Daniel↗
DOE OSTI2024

WaterTAP-REFLO models of Solar Still, Solar Still ZLD, Enhanced Evaporation pond results for baseline analysis

This folder contains results from models that were adapted into WaterTAP-REFLO. The files contain inputs and outputs for solar still, solar still ZLD, and enhanced evaporation pond unit process models for 4 different locations in the USA: Phoenix, Miami, Houston, and Baltimore. The WaterTAP-REFLO implementation may be different and thus may have different results. The data structure and content are described in a ReadMe.txt file. For WaterTAP-REFLO documentation and/or contact the developers please see: https://github.com/watertap-org/watertap-reflo.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2021

Water desalination through the dewpoint evaporative system

This paper presents the first numerical analysis of a novel Dew Point Desalination unit (DPD), which utilizes the phenomenon of the evaporative cooling process to minimize energy consumption. The proposed solution is based on a modular structure, which allows it to obtain any required water production capacity. The analyses for various operational parameters and various climatic conditions are based on the numerical simulations conducted using a validated mathematical model. The system performance was described with different factors, including specific energy consumption (SEC) and daily water production rate respected to 1 m^3*s^-1 of passing air stream (DWP). It is shown that the DPD system can operate in almost every climate zone, and the desalinated water production consumes less than 1.5 kWh*m^-3 of electric energy It is noted the best performance of the DPD system is achieved in the semi-arid, desert and subtropical climate zones. In these climate zones, the 2-stage DPD system allows the production of desalinated water with an electric energy consumption SEC lower than 0.5 kWh*m^-3. The additional benefit of the DPD system is its modularity. The presented DPD system stands as a module, that can be multiplied as needed to achieve the desired size of the desalination plant.

Desalination↗
DOE OSTI2020

Determining Activity Coefficients of SOA from Isothermal Evaporation in a Laboratory Chamber

Nonideal molecular interactions in aerosol particles influence the partitioning of semivolatile organic compounds (SVOCs). However, few direct measurements exist that determine activity coefficients (γ), which quantify nonideality, for individual organic compounds in different atmospheric mixtures. By measuring the isothermal evaporation of SOA formed from multifunctional SVOCs in an environmental chamber, this study determines the mole-fraction-based γ of the bulk SOA in a variety of pre-existing chemically complex particles, approximated as if the bulk SOA behaved like a single SVOC. These multicomponent mixtures contain molecular structures commonly found in the atmosphere. When treated as a single liquid phase, γ of the bulk SOA tends to increase from ~1 to ~5 as the organic seeds and the SOA have more differing polarities. A high computed γ value of 74 for a wet ammonium sulfate-SOA system indicates phase separation. The γ for some individual species was also quantified based on gas-phase measurements and AIOMFAC model predictions. However, the bulk SOA γ cannot be explained by the simplified speciated SVOC–seed interactions, suggesting incomplete compositional understanding of the bulk SOA. In this work, these results demonstrate a method to quantify nonideal behavior and show that it can occur in multicomponent mixtures and therefore influence OA formation, evolution, and lifetimes.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

FY25 Organic Evaporation Testing in Support of Hanford Sample-and-Send

The Hanford Waste Treatment and Immobilization Plant (WTP) is being built to treat and immobilize the approximately 56 million gallons of radioactive mixed waste stored in 156 underground storage tanks. The baseline method for immobilization of Low-Activity Waste (LAW) is vitrification, but additional immobilization capacity is needed to supplement the initial LAW melters. Additionally, efforts are being undertaken to accelerate the disposition of Pre-Treated Waste (PTW) in Hanford’s West Area. An alternative cementitious waste form is being investigated as an alternative immobilization method. However, one impediment to a cementitious waste form is the presence of Land Disposal Restricted (LDR) organic chemicals in tank waste, which are regulated on a concentration-based standard in the final waste form. Hence, if the quantity of organics in PTW and LAW is high enough, treatment may be needed to destroy or remove said organics to make a waste form compatible with disposal in a mixed low level waste landfill. This work evaluates evaporation as a potential avenue for treatment of LDR organics to eliminate the impediment and permit possible use of a cementitious waste form.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗