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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 973 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

ZnCr and ZnNb Cold Spray Coatings

Novel cold spray zinc-based alloy coatings have been investigated for corrosion protection of API 5L low carbon steel pipelines used in transporting natural gas. These different zinc alloy coatings are designed for use to help prevent internal corrosion and improve the lifespan of steel pipelines via sacrificial anodic protection. The corrosion behavior of these cold deposited zinc alloy coatings was investigated in CO2 saturated 3.5 wt.% NaCl solutions under simulated natural gas pipeline conditions. Electrochemical tests were conducted at 25 and 40 °C to determine the polarization resistance and galvanic current between each coating and the steel substrate in the galvanic couple. Tests were conducted at atmospheric, 1 bar, pressure. The results indicate that use of these coatings has the potential to increase the lifespan of steel pipelines above what a zinc coating alone could provide.

Teeter, Lucas↗
DOE OSTI2022

Systems and methods for application of stress corrosion cracking resistant cold spray coatings

Systems and methods for application of stress corrosion cracking resistant cold spray coatings include a method of forming a partial coating on a canister having a perimeter wall with a surface. The method may include identifying a compromised region on the surface of the wall of the canister, and impacting a substantially linear flow of particles of a powder against an area in the compromised region of the surface in a manner effective to cause the particles of the powder to bond to the surface of the wall to produce a coating on the area of the compromised region. The method may also include moving the substantially linear flow in a direction substantially parallel to the surface of the wall to cause the particles to impact an additional area of the compromised region to cause the particles to bond to the surface of the additional area.

Johnson, Kyle William↗
DOE OSTI2024

Corrosion Behavior of Zinc Cold Spray Coatings in a Simulated Natural Gas Environment Containing H2O, CO2, and H2S

The natural gas transmission pipeline network in the U.S. consists of approximately 300,000 miles, is made mainly of carbon steel, and was installed in the 1950s and 1960s. Understanding the pipeline steel behavior in natural gas will inform new pipeline designs and repurposing of existing pipelines. Sulfide stress cracking (SSC) is a problem for steel pipelines transporting natural gas or CO2 containing partial pressures of H2S higher than 0.3 kPa (0.05 psi). Therefore, the objective of this work is to mitigate internal corrosion in steel pipelines transporting natural gas containing H2S using cold spray coatings.

Belarbi, Zineb↗
DOE OSTI2023

Representative Phenomena of Cyclic Turbulent Combustion in High-Pressure Fuel Sprays

Abstract Cyclic variations in conventional diesel combustion engines can lead to large differences in engine out emissions even at steady operation. This study uses an optically accessible constant-pressure flow chamber to acquire fuel injections in quick succession to analyze mixing, auto-ignition, and combustion of diesel-surrogate n-heptane using multiple high-speed optical diagnostics. Prior studies have utilized fewer injections and/or they rely on analysis of ensemble average behavior. These approaches do not yield information on injection-to-injection variation or provide confidence in utilizing individual injection measurements for high-fidelity computational fluid dynamics(CFD) model validation. In this study, a large set of 500 injections is used to obtain global parameters including liquid length, vapor penetration length, ignition delay time, and lift-off length. Results for multiple injections are presented to illustrate large injection to injection variations. Potential sources for these variations are analyzed to conclude localized, small scale turbulence and rate of injection variations as the likely sources. Then, a statistical method based on z-scores is proposed and implemented to identify instantaneous injections that best represent the bulk data-set of jet boundaries measured independently by three different diagnostics. This synthesis of statistics-guided screening of data set and ensemble-average analysis offers higher confidence for CFD model validation relying upon both a representative single and average injection results.

42 ENGINEERING↗
DOE OSTI2022

Estimation of Sea Spray Aerosol Surface Area Over the Southern Ocean Using Scattering Measurements

This study focuses on methods to estimate dry marine aerosol surface area (SA) from bulk optical measurements. Aerosol SA is used in many models' ice nucleating particle (INP) parameterizations, as well as influencing particle light scattering, hygroscopic growth, and reactivity, but direct observations are scarce in the Southern Ocean (SO). Two campaigns jointly conducted in austral summer 2018 provided co-located measurements of aerosol SA from particle size distributions and lidar to evaluate SA estimation methods in this region. Mie theory calculations based on measured size distributions were used to test a proposed approximation for dry aerosol SA, which relies on estimating effective scattering efficiency (Q) as a function of Ångström exponent (å). For distributions with dry å < 1, Q = 2 was found to be a good approximation within ±50%, but for distributions with dry å > 1, an assumption of Q = 3 as in some prior studies underestimates dry aerosol SA by a factor of 2 or more. We propose a new relationship between dry å and Q, which can be used for –0.2 < å < 2, and suggest å = 0.8 as the cutoff between primary and secondary marine aerosol-dominated distributions. Application of a published methodology to retrieve dry marine aerosol SA from lidar extinction profiles overestimated aerosol SA by a factor of 3–5 during these campaigns. Using Microtops aerosol optical thickness measurements, we derive alternative lidar conversion parameters from our observations, applicable to marine aerosol over the SO.

54 ENVIRONMENTAL SCIENCES↗