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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 1,801 records · Page 100
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Geophysical Methods for Stratigraphic Identification

Although geophysics has been used for identifying subsurface fluid flow and contaminant spatial distributions at the Hanford Site and elsewhere, geophysics has not been generally used for identifying aquifer stratigraphy at environmentally relevant depths (> 70 m). This is because the bulk geophysical measurements of aquifer sediments cannot be directly related to sediment properties due to competing effects (e.g., porosity, pore-fluid conductivity, grain-sizes), thereby restricting the ability of conventional geophysical tools from discriminating their variation. Electrical resistivity tomography (ERT) is a method that can overcome these limitations because time-lapsed imaging, demonstrating changes in these properties over time, can be obtained from field sensors that can be left in place.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

Shear thinning rheology in a concentrated suspension of fibers: the role of attractive interactions

Fiber-reinforced composites are ubiquitously encountered in the engineering, automobile, and aerospace industries. Fabrication of these composites requires the mixing of fibers dispersed in a liquid, and the final structure is affected by fiber properties, interactions, and flow fields. A good understanding of the rheology of fiber suspensions can aid in the design and optimization of the fabrication processes. To this end, we simulate the simple shear flow of fiber suspensions by accounting for short range lubrication, van der Waals attractive, electrostatic repulsion interactions, as well as friction between fibers. Direct numerical simulations are performed using the Immersed Boundary Method where the fibers are modeled as flexible slender bodies governed by the Euler-Bernoulli beam theory and the fluid flow is resolved using the Navier-Stokes equations. The simulation results for the suspension viscosity and yield stress are consistent with the experimental data from the literature for polyamide fiber suspensions. The shear-thinning behavior becomes stronger as we increase the magnitude of attractive interactions. Furthermore, we perform a parametric study varying fiber flexibility, volume fraction, aspect ratio, inertia and examine suspension viscosity and yield stress.

Khan, Monsurul↗
NASA NTRSDate not supplied

Plant Watering in Low Gravity: The Study of the Fluid Dynamic Characteristics of Lunar Regolith Simulant for the Application of Crop Production Systems Using Scaled Capillary Devices

Bioregenerative life support is key to sustaining human life on the surface of other celestial bodies for missions beyond Low Earth Orbit (LEO). One example of such life support includes crop production systems capable of producing both plants and fungi for astronaut consumption. There have been numerous efforts to design and deploy such systems; however, there have been persistent fundamental issues with the water delivery systems. This study aims to understand and model the fluid dynamics of crop production systems to inform engineers about the key parameters needed for the design of such systems. The primary objective is to validate and expand upon NASA’s previous study, the Plant Water Management (PWM) experiments, to understand the fluid phenomena present in substrate-based systems. The model will then be expanded to include parameters for changing the test material of potential growth media as well as the varying water demands of the crop throughout its different stages in its life cycle. Specifically, this study is focused on the viability of using lunar regolith for agricultural purposes. Terrestrial-based scaled capillary models will be utilized to mimic the fluid phenomena occurring due to the low gravity environment seen on the lunar surface. Ultimately, the study will model the fluid flow present in the lunar regolith simulant and inform researchers on how to incorporate the material into crop production systems on the lunar surface.

gravity↗
NASA NTRS1987

Analytical and experimental studies of flow-induced vibration of SSME components

Components of the Space Shuttle Main Engines (SSMEs) are subjected to a severe environment that includes high-temperature, high-velocity flows. Such flows represent a source of energy that can induce and sustain large-amplitude vibratory stresses and/or result in fluidelastic instabilities. Three components are already known to have experienced failures in evaluation tests as a result of flow-induced structural motion. These components include the liquid-oxygen (LOX) posts, the fuel turbine bellows shield, and the internal inlet tee splitter vane. Researchers considered the dynamic behavior of each of these components with varying degrees of effort: (1) a theoretical and experimental study of LOX post vibration excited by a fluid flow; (2) an assessment of the internal inlet tee splitter vane vibration (referred to as the 4000-Hz vibration problem); and (3) a preliminary consideration of the bellows shield problem. Efforts to resolve flow-induced vibration problems associated with the SSMEs are summarized.

Chen, S. S.↗
NASA NTRS2018

Characterizing Performance of Additively Manufacturing Regenerative Cooled Combustion Chambers Through Hot Fire Testing

NASA Marshall Space Flight Center (MSFC) has developed several additive manufactured regenerative cooled combustion chambers from 2014 to present. Chambers have been constructed using the Selective Laser Melting (SLM) powder bed additive manufacturing (AM) technique. The materials used for the chambers has varied from Inconel 718, Inconel 625, GRCop-84, and C18150 metal alloys. The surface finish and build techniques used to successfully manufacture combustion chambers using the SLM AM result in as built surface finish and off nominal geometric features. This paper discusses and reviews the effects of surface roughness, flow area, and hydraulic performance of regenerative cooled combustion chambers. The thrust chambers designs tested ranged from 200 to 1,400 psia producing 1,000 to 35,000 lbf thrust. Empirical data from four test campaigns will be reviewed and related to design modeling parameters such as pressure drop, surface roughness, and actual fluid flow geometry. Correlation results with simple 2-D CFD modeling will also be presented. The goal of the work is to better understand how the finished additive manufactured component characteristics inside internal features can effect regenerative cooling chamber design. Adjustments to design methodology will be discussed and recommended based on the above results.

Garcia, C. P.↗
DOE OSTI2024

Computational Methods for Multi-Physics Simulation of Melting in Steelmaking

Iron and steel production accounts for approximately 8% of global carbon dioxide (CO) emissions. Pathways to decarbonize include replacing fossil fuels in iron ore reduction and electrifying other steelmaking processes. Iron pellets produced by hydrogen, called Hydrogen Direct Reduced Iron (HDRI), have property differences from those produced using conventional DRI processes. These differences may impact melting in electric arc furnaces (EAF) and other downstream processes. The physical properties of iron pellets vary significantly with temperature during heating, complicating predictions of their behavior. In this project, we seek to develop an integrated simulation, including the fluid flow and convective thermal transport around the pellet particle. We also examine conduction and phase changes within the particle as they impact the melting process. We use adaptive mesh refinement (AMR) to resolve both the changing size of the particle and the complex physics of the interaction between the pellet and the surrounding fluid. We base our simulations on the AMReX-incflo module, which allows large-scale Navier-Stokes simulation while resolving the changing particle size during melting. As we advance our numerical tools, we anticipate an improved understanding of the dynamics of HDRI melting, which will, in turn, accelerate the adoption of low-carbon technologies in the steelmaking industry.

AMReX↗
NASA NTRS1986

Some influences of approximate values for velocity, density and total temperature sensitivities on hot wire anemometer results

There is a renewed interest in hot wire anemometry at transonic speeds. Recent results were published which indicate that at transonic speeds a heated wire is sensitive only to mass flow and total temperature, results similar to those obtained for supersonic flows. Other results were obtained to show that the sensitivity is a function of velocity, density, and total temperature, results in agreement with many of those obtained in the 1950s. An analysis of anemometry results was made to evaluate possible errors when various assumptions were made concerning the sensitivity of a heated wire to fluid flow variables.

Stainback, P. C.↗
NASA NTRS2015

Fast Response, Open-Celled Porous, Shape Memory Effect Actuators with Integrated Attachments

This invention relates to the exploitation of porous foam articles exhibiting the Shape Memory Effect as actuators. Each foam article is composed of a plurality of geometric shapes, such that some geometric shapes can fit snugly into or around rigid mating connectors that attach the Shape Memory foam article intimately into the load path between a static structure and a moveable structure. The foam is open-celled, composed of a plurality of interconnected struts whose mean diameter can vary from approximately 50 to 500 microns. Gases and fluids flowing through the foam transfer heat rapidly with the struts, providing rapid Shape Memory Effect transformations. Embodiments of porous foam articles as torsional actuators and approximately planar structures are disposed. Simple, integral connection systems exploiting the ability to supply large loads to a structure, and that can also supply hot and cold gases and fluids to effect rapid actuation are also disposed.

Jardine, Andrew Peter↗
DOE OSTI2016

Heat and mass exchangers having extruded plates

A heat and mass exchanger including a plurality of vertical plates that are spaced apart from one another by gaps so as to allow a first gas to flow between the plates. Each plate includes a front wall that defines a front surface of the plate, a back wall that defines a back surface of the plate, and separate, parallel channels disposed between the front and back walls. The parallel channels include a first set of parallel channels, a first liquid flowing within the first set of channels and over one of the front or back surfaces of the plate, the first liquid having a bulk composition comprising one or more constituents, the first gas having at least one constituent in common with the first liquid, and a second set of parallel channels, a first fluid flowing within the second set of channels.

Lowenstein, Andrew↗
NASA NTRS1988

The development of an intelligent interface to a computational fluid dynamics flow-solver code

Researchers at NASA Lewis are currently developing an 'intelligent' interface to aid in the development and use of large, computational fluid dynamics flow-solver codes for studying the internal fluid behavior of aerospace propulsion systems. This paper discusses the requirements, design, and implementation of an intelligent interface to Proteus, a general purpose, 3-D, Navier-Stokes flow solver. The interface is called PROTAIS to denote its introduction of artificial intelligence (AI) concepts to the Proteus code.

Williams, Anthony D.↗
NASA NTRS1988

The development of an intelligent interface to a computational fluid dynamics flow-solver code

Researchers at NASA Lewis are currently developing an 'intelligent' interface to aid in the development and use of large, computational fluid dynamics flow-solver codes for studying the internal fluid behavior of aerospace propulsion systems. This paper discusses the requirements, design, and implementation of an intelligent interface to Proteus, a general purpose, three-dimensional, Navier-Stokes flow solver. The interface is called PROTAIS to denote its introduction of artificial intelligence (AI) concepts to the Proteus code.

Williams, Anthony D.↗
DOE OSTI2019

Study on the Impact Characteristics of Submerged CO{sub 2} and O{sub 2} Mixed Injection (S-COMI) in EAF Steelmaking

A new type of oxygen-supplying technology was developed for electric arc furnace (EAF) steelmaking using submerged CO{sub 2} and O{sub 2} mixed injection (S-COMI). S-COMI injects O{sub 2} into the molten steel bath directly by a submerged injector installed in the furnace bed; so the metallurgical reactions can be accelerated with a high utilization ratio of oxygen. However, there has been limited research on the impact characteristics of the S-COMI submerged gas jet in EAF steelmaking. In this study, water model experiments and numerical simulations were carried out to analyze the submerged gas jet behavior, and a theoretical model was built to depict the axis trajectory of submerged gas jet in the liquid bath. The numerical results were validated against the water model experiments to show that the gas flow rate and the installed angle have a significant influence on the jet impact characteristics. The results show that as the gas flow rate increases, the horizontal and vertical penetration distances increase; as the installed angle increases, the horizontal penetration distance increases while the vertical penetration distance decreases. In addition, the erosion mechanism of the element around the submerged injector exit was studied. As the installed angle increases, the velocity component in the vertical direction increases, the fluid flow is accelerated, and the wall shear stress of the underpart of the injector element increases. Therefore, the erosion rate of the upper part of the element decreases, while that of the underpart increases.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Characterization of Pliocene and Miocene Formations in the Wilmington Graben, Offshore Los Angeles, for Large-Scale Geologic Storage of CO₂

Geomechanics Technologies has completed a detailed characterization study of the Wilmington Graben offshore Southern California area for large-scale CO₂ storage. This effort has included: an evaluation of existing wells in both State and Federal waters, field acquisition of about 175 km (109 mi) of new seismic data, new well drilling, development of integrated 3D geologic, geomechanics, and fluid flow models for the area. The geologic analysis indicates that more than 796 MMt of storage capacity is available within the Pliocene and Miocene formations in the Graben for midrange geologic estimates (P50). Geomechanical analyses indicate that injection can be conducted without significant risk for surface deformation, induced stresses or fault activation. Numerical analysis of fluid migration indicates that injection into the Pliocene Formation at depths of 1525 m (5000 ft) would lead to undesirable vertical migration of the CO₂ plume. Recent well drilling however, indicates that deeper sand is present at depths exceeding 2135 m (7000 ft), which could be viable for large volume storage. For vertical containment, injection would need to be limited to about 250,000 metric tons per year per well, would need to be placed at depths greater than 7000ft, and would need to be placed in new wells located at least 1 mile from any existing offset wells. As a practical matter, this would likely limit storage operations in the Wilmington Graben to about 1 million tons per year or less. A quantitative risk analysis for the Wilmington Graben indicate that such large scale CO₂ storage in the area would represent higher risk than other similar size projects in the US and overseas.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1998

The Role of Multiphysics Simulation in Multidisciplinary Analysis

This article describes the applications of the Spectrum(Tm) Solver in Multidisciplinary Analysis (MDA). Spectrum, a multiphysics simulation software based on the finite element method, addresses compressible and incompressible fluid flow, structural, and thermal modeling as well as the interaction between these disciplines. Multiphysics simulation is based on a single computational framework for the modeling of multiple interacting physical phenomena. Interaction constraints are enforced in a fully-coupled manner using the augmented-Lagrangian method. Within the multiphysics framework, the finite element treatment of fluids is based on Galerkin-Least-Squares (GLS) method with discontinuity capturing operators. The arbitrary-Lagrangian-Eulerian method is utilized to account for deformable fluid domains. The finite element treatment of solids and structures is based on the Hu-Washizu variational principle. The multiphysics architecture lends itself naturally to high-performance parallel computing. Aeroelastic, propulsion, thermal management and manufacturing applications are presented.

Rifai, Steven M.↗
NASA NTRS1986

Hypersonic low-density solutions of the Navier-Stokes equations with chemical nonequilibrium and multicomponent surface slip

Solutions of the Navier-Stokes equations with chemical nonequilibrium and multicomponent surface slip are presented along the stagnation streamline under low-density hypersonic flight conditions. The conditions analyzed are those encountered by the nose region of the Space Shuttle Orbiter during reentry. A detailed comparison of the Navier-Stokes (NS) results is made with the viscous shock-layer (VSL) and Direct Simulation Monte Carlo (DSMC) predictions. With the inclusion of surface-slip boundary conditions in NS calculations, the surface heat transfer and other flow field quantities adjacent to the surface are predicted favorably with the DSMC calculations from 75 km to 115 km in altitude. Therefore, the practical range for the applicability of Navier-Stokes solutions is much wider than previously thought. This is appealing because the continuum (NS and VSL) methods are commonly used to solve the fluid flow problems and are less demanding in terms of computer resource requirements than the noncontinuum (DSMC) methods. The NS solutions agree well with the VSL results for altitudes less than 92 km. An assessment is made of the frozen flow approximation employed in the VSL calculations.

Gupta, R. N.↗
NASA NTRS1998

A 2.5D Single Passage CFD Model for Centrifugal Pumps

This paper describes the single passage model based on CFD to analyze the flow in blade passages of a centrifugal pump. The model consists of the flow passage between two impeller blades and the spaces in the inlet eye as well as in the volute. The incompressible Navier-Stokes equations in the conservation form are solved by a finite difference method. The code is designed to investigate the velocity and pressure distributions and intended to investigate how the pump design affects fluid flow through the rotor as well as the pump performance. An early part of the paper investigates the behavior of the model as well as validity of the assumptions made in the model. Then, applications to a rotodynamic heart pump are presented.

Nakamura S.↗
DOE OSTI2015

Fully-Implicit Orthogonal Reconstructed Discontinuous Galerkin for Fluid Dynamics with Phase Change

A new reconstructed Discontinuous Galerkin (rDG) method, based on orthogonal basis/test functions, is developed for fluid flows on unstructured meshes. Orthogonality of basis functions is essential for enabling robust and efficient fully-implicit Newton-Krylov based time integration. The method is designed for generic partial differential equations, including transient, hyperbolic, parabolic or elliptic operators, which are attributed to many multiphysics problems. We demonstrate the method’s capabilities for solving compressible fluid-solid systems (in the low Mach number limit), with phase change (melting/solidification), as motivated by applications in Additive Manufacturing (AM). We focus on the method’s accuracy (in both space and time), as well as robustness and solvability of the system of linear equations involved in the linearization steps of Newton-based methods. The performance of the developed method is investigated for highly-stiff problems with melting/solidification, emphasizing the advantages from tight coupling of mass, momentum and energy conservation equations, as well as orthogonality of basis functions, which leads to better conditioning of the underlying (approximate) Jacobian matrices, and rapid convergence of the Krylov-based linear solver.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2022

Single-Phase Dielectric Fluid Thermal Management for Power-Dense Automotive Power Electronics

This paper describes the design and performance of a dielectric fluid cooling concept for automotive power electronics. The concept combines a low-thermal-resistance package (which eliminates metalized ceramic substrates) with a high-performance convective cooling strategy (slot jets impinging on finned surfaces). Modeling was first used to design the cooling system to maximize thermal performance and minimize pumping power. Additionally, a prototype was then fabricated, and experiments were conducted to validate the model predictions using three fluids at various fluid flow rates (16.7 cm 3 /s [1 L/min] to 68.3 cm 3 /s [4.1 L/min]) and inlet temperatures (30C and 70C). The final design was compact (120-cm 3 total volume, including heat exchanger and conceptual power modules) and cooled 12 devices (e.g., silicon carbide). The validated model was then used to predict the junction-to-fluid thermal resistance and pumping power for various conditions, including 40C fluid temperature. The results predict thermal resistance values as low as 19 mm 2 K/W are possible using the dielectric fluid cooling approach. The dielectric fluid cooling system is predicted to provide thermal resistance and pumping power values that are approximately 56% and 90% lower, respectively, compared to an automotive power electronics cooling system.

30 DIRECT ENERGY CONVERSION↗

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