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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
NASA NTRS2002

Design Through Manufacturing: The Solid Model-Finite Element Analysis Interface

State-of-the-art computer aided design (CAD) presently affords engineers the opportunity to create solid models of machine parts reflecting every detail of the finished product. Ideally, in the aerospace industry, these models should fulfill two very important functions: (1) provide numerical. control information for automated manufacturing of precision parts, and (2) enable analysts to easily evaluate the stress levels (using finite element analysis - FEA) for all structurally significant parts used in aircraft and space vehicles. Today's state-of-the-art CAD programs perform function (1) very well, providing an excellent model for precision manufacturing. But they do not provide a straightforward and simple means of automating the translation from CAD to FEA models, especially for aircraft-type structures. Presently, the process of preparing CAD models for FEA consumes a great deal of the analyst's time.

Rubin, Carol↗
NASA NTRS2006

Lower-Conductivity Ceramic Materials for Thermal-Barrier Coatings

Doped pyrochlore oxides of a type described below are under consideration as alternative materials for high-temperature thermal-barrier coatings (TBCs). In comparison with partially-yttria-stabilized zirconia (YSZ), which is the state-of-the-art TBC material now in commercial use, these doped pyrochlore oxides exhibit lower thermal conductivities, which could be exploited to obtain the following advantages: For a given difference in temperature between an outer coating surface and the coating/substrate interface, the coating could be thinner. Reductions in coating thicknesses could translate to reductions in weight of hot-section components of turbine engines (e.g., combustor liners, blades, and vanes) to which TBCs are typically applied. For a given coating thickness, the difference in temperature between the outer coating surface and the coating/substrate interface could be greater. For turbine engines, this could translate to higher operating temperatures, with consequent increases in efficiency and reductions in polluting emissions. TBCs are needed because the temperatures in some turbine-engine hot sections exceed the maximum temperatures that the substrate materials (superalloys, Si-based ceramics, and others) can withstand. YSZ TBCs are applied to engine components as thin layers by plasma spraying or electron-beam physical vapor deposition. During operation at higher temperatures, YSZ layers undergo sintering, which increases their thermal conductivities and thereby renders them less effective as TBCs. Moreover, the sintered YSZ TBCs are less tolerant of stress and strain and, hence, are less durable.

Bansal, Narottam P.↗
DOE OSTI2021

Size- and Phase-Controlled Nanometer-Thick ß-Ga2O3 Films with Green Photoluminescence for Optoelectronic Applications

Realization and optimization of the tunable/enhanced optical properties is critical to further advance the field of optoelectronics, photonics, and nano-electronics. In this context, here, we demonstrate green-emission characteristics with a ~30 fold enhancement in selectively engineered nanocrystalline Ga2O3 with a control over size, phase and interface nanostructure. Pulsed-laser-deposited ß-phase Ga2O3 films with an average crystallite size of ~9 nm along with a highly dense, close-compact nano-columnar structure with lowest possible defect density facilitates the thirty-fold enhancement in the photoluminescence (PL) intensity in green-region. Enhanced PL-emission in the optimized, engineered nano-architecture sheds light in designing Ga2O3-materials for promising future optoelectronic/photocatalytic applications.

Ga2O3, Nanocrystalline Films, Pulsed-Laser Deposit↗
DOE OSTI2021

Power Cylinder Friction Reduction Through Coatings, Surface Finish and Design

About 7-10% of the total energy input in a vehicle is lost due to mechanical friction, and in an engine, about 50% of the total frictional losses occur at the interface between the cylinder and pistons and piston rings. Therefore, this interface offers great opportunities for friction reduction. The goal of this proposed study is to demonstrate friction reduction potential using advanced coatings, surface finish, and design on power cylinder system containing cylinder bore, piston rings, crankshaft, and advanced engine oils. Experience through years of research in this area lead us to believe that full benefit potential can be realized only by considering a systems approach.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS2003

Enhancing the Human Factors Engineering Role in an Austere Fiscal Environment

An austere fiscal environment in the aerospace community creates pressures to reduce program costs, often minimizing or sometimes even deleting the human interface requirements from the design process. With an assumption that the flight crew can recover real time from a poorly human factored space vehicle design, the classical crew interface requirements have been either not included in the design or not properly funded, though carried as requirements. Cost cuts have also affected quality of retained human factors engineering personnel. In response to this concern, planning is ongoing to correct the acting issues. Herein are techniques for ensuring that human interface requirements are integrated into a flight design, from proposal through verification and launch activation. This includes human factors requirements refinement and consolidation across flight programs; keyword phrases in the proposals; closer ties with systems engineering and other classical disciplines; early planning for crew-interface verification; and an Agency integrated human factors verification program, under the One NASA theme. Importance is given to communication within the aerospace human factors discipline, and utilizing the strengths of all government, industry, and academic human factors organizations in an unified research and engineering approach. A list of recommendations and concerns are provided in closing.

Stokes, Jack W.↗
NASA NTRS1989

The Sizing and Optimization Language (SOL): A computer language to improve the user/optimizer interface

The nonlinear mathematical programming method (formal optimization) has had many applications in engineering design. A figure illustrates the use of optimization techniques in the design process. The design process begins with the design problem, such as the classic example of the two-bar truss designed for minimum weight as seen in the leftmost part of the figure. If formal optimization is to be applied, the design problem must be recast in the form of an optimization problem consisting of an objective function, design variables, and constraint function relations. The middle part of the figure shows the two-bar truss design posed as an optimization problem. The total truss weight is the objective function, the tube diameter and truss height are design variables, with stress and Euler buckling considered as constraint function relations. Lastly, the designer develops or obtains analysis software containing a mathematical model of the object being optimized, and then interfaces the analysis routine with existing optimization software such as CONMIN, ADS, or NPSOL. This final state of software development can be both tedious and error-prone. The Sizing and Optimization Language (SOL), a special-purpose computer language whose goal is to make the software implementation phase of optimum design easier and less error-prone, is presented.

Lucas, S. H.↗
NASA NTRS1982

Combustion performance and heat transfer characterization of LOX/hydrocarbon type propellants. Task 3: Data dump

A preliminary characterization of Orbital Maneuvering System (OMS) and Reaction Control System (RCS) engine point designs over a range of thrust and chamber pressure for several hydrocarbon fuels is reported. OMS and RCS engine point designs were established in two phases comprising baseline and parametric designs. Interface pressures, performance and operating parameters, combustion chamber cooling and turboprop requirements, component weights and envelopes, and propellant conditioning requirements for liquid to vapor phase engine operation are defined.

Hart, S. W.↗
DOE OSTI2024

Electro-Chemo-Mechanical Evolution at the Garnet Solid Electrolyte–Cathode Interface

Solid-state batteries promise higher energy density and improved safety compared with lithium-ion batteries. However, electro-chemomechanical instabilities at the solid electrolyte interface with the cathode and the anode hinder their large scale implementation. Here, in this study, we focus on resolving electro-chemo-mechanical instability mechanisms and their onset conditions between a state-of-the-art cathode, LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622), and the garnet Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte. We used thin-film NMC622 on LLZO pellets to place the interfacial region within the detection depth of the X-ray characterization techniques. The experimental probes of the near-interface region included in operando X-ray absorption spectroscopy and ex situ focused ion beam scanning electron microscopy. Electrochemical degradation was not observable during cycling at room temperature with 4.3 V versus Li/Li + charge voltage cutoff, or with stepwise potentiostatic hold up to 4.1 V versus Li/Li + . In contrast, secondary phases including reduced transition metal species (Ni 2+ , Co 2+ ) were found after cycling up to 4.3 V versus Li/Li + at 80 °C and during potentiostatic hold at 4.3 V versus Li/Li + (Ni 2+ ). Intergranular cracks between NMC622 grains and delamination at the NMC622|LLZO interface occurred readily after the first charge. These interface reaction products and mechanical failure lowered the capacity and cell efficiency due to partial loss of the NMC622 phase, partial loss of contact at the interface, and a higher polarization resistance. Electrochemical instability between delithiated NMC622 and LLZO could be mitigated by using a low charge voltage cutoff or cycling at lower temperature. Ways to engineer the mechanical properties to avoid crack deflection and delamination at the interface are also discussed for enhancing mechanical stability.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Advanced development receiver thermal vacuum tests with cold wall

The first ever testing of a full size solar dynamic heat receiver using high temperature thermal energy storage was completed. The heat receiver was designed to meet the requirements for operation on the Space Station Freedom. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partially simulate a low Earth orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to produce flux distributions typical of candidate concentrators. A closed Brayton cycle engine simulator conditioned a helium xenon gas mixture to specific interface conditions to simulate various operational modes of the solar dynamic power module. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles were completed during the test conduct period. The test hardware, execution of testing, test data, and post test inspections are described.

Sedgwick, Leigh M.↗
NASA NTRS1999

True Concurrent Thermal Engineering Integrating CAD Model Building with Finite Element and Finite Difference Methods

Thermal engineering has long been left out of the concurrent engineering environment dominated by CAD (computer aided design) and FEM (finite element method) software. Current tools attempt to force the thermal design process into an environment primarily created to support structural analysis, which results in inappropriate thermal models. As a result, many thermal engineers either build models "by hand" or use geometric user interfaces that are separate from and have little useful connection, if any, to CAD and FEM systems. This paper describes the development of a new thermal design environment called the Thermal Desktop. This system, while fully integrated into a neutral, low cost CAD system, and which utilizes both FEM and FD methods, does not compromise the needs of the thermal engineer. Rather, the features needed for concurrent thermal analysis are specifically addressed by combining traditional parametric surface based radiation and FD based conduction modeling with CAD and FEM methods. The use of flexible and familiar temperature solvers such as SINDA/FLUINT (Systems Improved Numerical Differencing Analyzer/Fluid Integrator) is retained.

Panczak, Tim↗
NASA NTRS1993

Open environments to support systems engineering tool integration: A study using the Portable Common Tool Environment (PCTE)

A study of computer engineering tool integration using the Portable Common Tool Environment (PCTE) Public Interface Standard is presented. Over a 10-week time frame, three existing software products were encapsulated to work in the Emeraude environment, an implementation of the PCTE version 1.5 standard. The software products used were a computer-aided software engineering (CASE) design tool, a software reuse tool, and a computer architecture design and analysis tool. The tool set was then demonstrated to work in a coordinated design process in the Emeraude environment. The project and the features of PCTE used are described, experience with the use of Emeraude environment over the project time frame is summarized, and several related areas for future research are summarized.

Eckhardt, Dave E., Jr.↗
DOE OSTI2020

Transcritical diffuse-interface hydrodynamics of propellants in high-pressure combustors of chemical propulsion systems

Rocket engines and high-power new generations of gas-turbine jet engines and diesel engines oftentimes involve the injection of one or more reactants at subcritical temperatures into combustor environments at high pressures, and more particularly at pressures higher than those corresponding to the critical points of the individual components of the mixture, which typically range from 13 to 50 bars for most propellants. This class of trajectories in the thermodynamic space has been traditionally referred to as transcritical. However, the fundamental understanding of fuel atomization, vaporization, mixing, and combustion processes at such high pressures remains elusive. In particular, whereas fuel sprays are relatively well characterized at normal pressures, analyses of dispersion of fuel in high-pressure combustors are hindered by the limited experimental diagnostics and theoretical formulations available. The description of the thermodynamics of hydrocarbon-fueled mixtures employed in chemical propulsion systems is complex and involves mixing-induced phenomena, including an elevation of the critical point whereby the coexistence region of the mixture extends up to pressures much larger than the critical pressures of the individual components. As a result, interfaces subject to surface-tension forces may persist in multicomponent systems despite the high pressures, and may give rise to unexpected spray-like atomization dynamics that are otherwise absent in monocomponent systems above their critical point. In this article, the current understanding of this phenomenon is reviewed within the context of propulsion systems fueled by heavy hydrocarbons. Emphasis is made on analytical descriptions at mesoscopic scales of interest for computational fluid dynamics. In particular, a set of modifications of the constitutive laws in the Navier–Stokes equations for multicomponent flows, supplemented with a high-pressure equation of state and appropriate redefinitions of the thermodynamic potentials, are introduced in this work based on an extended version of the diffuse-interface theory of van der Waals. The resulting formulation involves revisited forms of the stress tensor and transport fluxes of heat and species, and enables a description of the mesoscopic volumetric effects induced by transcritical interfaces consistently with the thermodynamic phase diagram of the mixture at high pressures. Additionally, applications of the theory are illustrated in canonical problems, including dodecane/nitrogen transcritical interfaces in non-isothermal systems. The results indicate that a transcritical interface is formed between the propellant streams that persists downstream of the injection orifice over distances of the same order as the characteristic thermal-entrance length of the fuel stream. The transcritical interface vanishes at an edge that gives rise to a fully supercritical mixing layer.

02 PETROLEUM↗
NASA NTRS1998

Secure Web-based Ground System User Interfaces over the Open Internet

A prototype has been developed which makes use of commercially available products in conjunction with the Java programming language to provide a secure user interface for command and control over the open Internet. This paper reports successful demonstration of: (1) Security over the Internet, including encryption and certification; (2) Integration of Java applets with a COTS command and control product; (3) Remote spacecraft commanding using the Internet. The Java-based Spacecraft Web Interface to Telemetry and Command Handling (Jswitch) ground system prototype provides these capabilities. This activity demonstrates the use and integration of current technologies to enable a spacecraft engineer or flight operator to monitor and control a spacecraft from a user interface communicating over the open Internet using standard World Wide Web (WWW) protocols and commercial off-the-shelf (COTS) products. The core command and control functions are provided by the COTS Epoch 2000 product. The standard WWW tools and browsers are used in conjunction with the Java programming technology. Security is provided with the current encryption and certification technology. This system prototype is a step in the direction of giving scientist and flight operators Web-based access to instrument, payload, and spacecraft data.

Langston, James H.↗
NASA NTRS1993

Deep Space Network (DSN), Network Operations Control Center (NOCC) computer-human interfaces

The Network Operations Control Center (NOCC) of the DSN is responsible for scheduling the resources of DSN, and monitoring all multi-mission spacecraft tracking activities in real-time. Operations performs this job with computer systems at JPL connected to over 100 computers at Goldstone, Australia and Spain. The old computer system became obsolete, and the first version of the new system was installed in 1991. Significant improvements for the computer-human interfaces became the dominant theme for the replacement project. Major issues required innovating problem solving. Among these issues were: How to present several thousand data elements on displays without overloading the operator? What is the best graphical representation of DSN end-to-end data flow? How to operate the system without memorizing mnemonics of hundreds of operator directives? Which computing environment will meet the competing performance requirements? This paper presents the technical challenges, engineering solutions, and results of the NOCC computer-human interface design.

Ellman, Alvin↗
NASA NTRS2005

Space Physics Data Facility Web Services

The Space Physics Data Facility (SPDF) Web services provides a distributed programming interface to a portion of the SPDF software. (A general description of Web services is available at http://www.w3.org/ and in many current software-engineering texts and articles focused on distributed programming.) The SPDF Web services distributed programming interface enables additional collaboration and integration of the SPDF software system with other software systems, in furtherance of the SPDF mission to lead collaborative efforts in the collection and utilization of space physics data and mathematical models. This programming interface conforms to all applicable Web services specifications of the World Wide Web Consortium. The interface is specified by a Web Services Description Language (WSDL) file. The SPDF Web services software consists of the following components: 1) A server program for implementation of the Web services; and 2) A software developer s kit that consists of a WSDL file, a less formal description of the interface, a Java class library (which further eases development of Java-based client software), and Java source code for an example client program that illustrates the use of the interface.

Candey, Robert M.↗
NASA NTRSDate not supplied

Development of a Human Systems Integration Plan

NASA defines Human Systems Integration (HSI) as part of the overall systems engineering and acquisition strategy for space systems. The HSI Plan defines how HSI activities will be implemented across the lifecycle of the mission, as required by NPR 7123.1C, NASA Systems Engineering Processes and Requirements, and NPR 8705.2C Human-Rating Requirements for Space Systems. The goal of this presentation is to share with government and industry how an HSI Plan can be implemented. The presentation will cover HSI implementation for flight systems, vehicle processing, and interfaces. These are divided into six NASA HSI Domains: human factors engineering, operations resources, safety, training, maintainability and supportability, habitability and environment. HSI activities go across the mission’s lifecycle from pre-formulation and acquisition through design, development, operations, maintenance, and decommissioning. The HSI Plan includes a description of the HSI activities and products that are essential for human rating, operability, maintainability, supportability, and affordability of the mission systems. It also describes the role of the HSI Team required as part of the Human Rating process. The HSI Plan utilizes the operational expertise within NASA to ensure designs and testing are successful, leading to acceptable human spaceflight vehicles.

Jackelynne Silva-Martinez↗
DOE OSTI2020

In situ , in vivo , and in operando imaging and spectroscopy of liquids using microfluidics in vacuum

This review offers a succinct overview of the development of a vacuum-compatible microfluidic reactor system for analysis at the liquid vacuum interface (SALVI), and its diverse applications in in situ, in vivo, and in operando imaging of liquid surfaces as well as the air-liquid (a-l), liquid-liquid (l-l), and solid-liquid (s-l) interfaces in the past decade. SALVI is one of the first microfluidics-based reactors that has enabled direct analysis of volatile liquids in vacuum surface tools such as scanning electron microscopy (SEM) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Its integration into ambient and vacuum spectroscopy and microscopy is illustrated. Several applications are highlighted including (1) imaging nanoparticles in liquid using in situ SEM; (2) mapping the evolving l-l interface using in situ x-ray absorption spectroscopy and ToF-SIMS; (3) following complex a-l interfacial oxidation reaction products using in situ ToF-SIMS; (4) capturing biological interfaces of cells and microbes via in vivo multimodal and correlative imaging; and (5) monitoring the dynamic solid electrode and liquid electrolyte interface using in operando molecular imaging. Finally, outlook and recommendations are presented. Besides showing the holistic information volume obtained by real-time multiplexed imaging, this review intends to convey the importance of tool development in revolutionizing surface and interface analysis using vacuum platforms previously limited to solid surfaces. Microfluidics is manifested to be not limited to ambient conditions in many examples in this review. Moreover, fundamental interfacial phenomena underpinning mass and charge transfer can now be pursued in real time via innovated chemical imaging and spectroscopy.

42 ENGINEERING↗