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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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Complete Genome Sequence of a Parabacteroides distasonis Strain (CavFT hAR46) Isolated from a Gut Wall-Cavitating Microlesion in a Patient with Severe Crohn’s Disease

Crohn’s disease (CD) is a chronic inflammatory bowel disease (IBD) of the digestive tract in humans. There is evidence that Parabacteroides distasonis could contribute to IBD. Here, we present the complete genome sequence of a strain designated CavFT-hAR46, which was isolated from a gut intramural cavernous fistulous tract (CavFT) microlesion in a CD patient.

Yang, Falong↗
DOE OSTI2018

Spectroscopy of a Cavitating Liquid in the Optical and X-ray Spectral Ranges

Results of spectroscopic investigation of a multibubble sonoluminescence and a hydrodynamic luminescence of glycerol in the optical range between 400 and 700 nm and in the X-ray spectral interval between 1 and 70 keV are presented. Continuous spectrum the shape of which is sufficiently well described by the normal distribution with respect to photon energy was obtained for both sono- and hydroluminescence in the optical spectral range. Based on the identity of the spectra, a conclusion can be drawn that the effects of the sono- and hydroluminescence are of the same physical nature. The shape of the obtained spectra suggests that the observed glow of a liquid under mechanical action represents fluorescence of only one type of centers in a condensed medium. X-ray radiation is absent in the specified energy range. Although an X-ray spectrometer detects some a signal of some kind, in reality, this turns out to be noise created by the magnetostrictive transducer of an ultrasonic generator.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Development of a Cavity Collapse Model of Cavitation Bubbles in Water in One and Two Dimensions using the Finite Volume FLAG Hydrocode at Atmospheric Pressure and 293K (Final Report)

Los Alamos National Laboratory was established in 1943 as the home of Project Y, The Manhattan Project directed by J. Robert Oppenheimer, with the aim of developing the world’s first atomic bomb. The project was successful and on the 16 th of July 1945 the first atomic bomb was detonated at Trinity Site. This development led to the creation of Little Boy and Fat Man, the two nuclear bombs dropped in Japan to end World War II. Today the laboratory has the responsibility of ensuring that the American nuclear deterrent is safe, secure and reliable. To ensure that this important responsibility is met, the laboratory carries out science in a wide range of areas. Its responsibilities are shared with Sandia National Laboratory (SNL) and Lawrence Livermore National Laboratory (LLNL). All are laboratories managed by the Department of Energy’s National Nuclear Security Administration (NNSA).

36 MATERIALS SCIENCE↗
DOE OSTI2018

Fundamental study of key issues related to advanced sCO 2 Brayton cycle: Prototypic HX development and cavitation

Diffusion bonded heat exchangers are the leading candidates for the sCO 2 Brayton cycles in next generation nuclear power plants. Commercially available diffusion bonded heat exchangers utilize set of continuous semi-circular zigzag micro channels to increase the heat transfer area and enhance heat transfer through increased turbulence production. Such heat exchangers can lead to excessive pressure drop as well as flow maldistribution in the case of poorly designed flow distribution headers. The goal of the current project is to fabricate and test potential discontinuous fin patterns for diffusion bonded heat exchangers; which can achieve desired thermal performance at lower pressure drops. Prototypic discontinuous offset rectangular and Airfoil fin surface geometries were chemically etched on to 316 stainless steel plate and sealed against an un-etched flat pate using O-ring seal emulating diffusion bonded heat exchangers. Thermal-hydraulic performance of these prototypic discontinuous fin geometries was experimentally evaluated and compared to the existing data for the continuous zigzag channels. The data generated from this project will serve as the database for future testing and validation of numerical models.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS1967

Cavitation in mechanical face seals.

Gas cavities in mechanical face seals operating with hydrodynamic films, obtaining solutions to Reynolds equation for hydrodynamic lubrication

Findlay, J. A.↗
NASA NTRS1974

Role of physical properties of liquids in cavitation erosion

The dependence of erosion rates on the ambient temperature of water is discussed. The assumption that the gas inside the bubble is compressed adiabatically during collapse gives better agreement with experiments than the assumption that the gas is isothermally compressed. Acoustic impedance is an important liquid parameter that governs the erosion intensity in vibratory devices. The investigation reveals that the major physical properties of liquids governing the intensity of erosion include density, sound speed, surface tension, vapor pressure, gas content, and nuclei distribution.

Thiruvengadam, A.↗
NASA NTRS1974

Asperity lubrication and cavitation in face seals

The basic aspect of parallel-surface lubrication that distinguishes it from other areas of lubrication technology is that classical lubrication theory does not predict the existence of a stable hydrodynamic film for steady-state, isothermal, incompressible flow between smooth, parallel surfaces. Hydrodynamic films between apparently parallel surfaces have been observed in practice and are often essential for the reliable performance of thrust bearings and seals. In order to account for this fortunate discrepancy between classical theory and experiment, load-support mechanisms relating to accidential features characteristic of seal performance, which relax one or more of the assumptions in the classical theory and permit the theoretical prediction of load support are proposed. Some of the features that have been analyzed are vibratory effects such as wobble and bounce, surface waviness, nonsymmetric rotation resulting from various types of misalignment, lubricant density change, non-Newtonian lubricant effects, and surface roughness.

Walowitt, J. A.↗