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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 1,207 records · Page 67
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Advancing Replicable Solutions for High-Performance Homes in the Southeast

Southface Energy Institute (Southface) partnered with owners and/or builders with various market constraints and ultimate goals for three projects in different climate zones: Savannah, GA (CZ 2), Clemson, SC (CZ 3), and LaFayette, GA (CZ 4). This report documents the design process, computational energy modeling, construction, envelope performance metrics, long-term monitoring results, and successes and failures of the design and execution of these high performance homes. The three bedroom/two bathroom test home in Savannah Gardens on an elevated slab foundation has a semi-conditioned, encapsulated attic. A neighboring home built to EarthCraft specifications was also monitored as a control for exterior foam insulation and a heat pump water heater (HPWH). For the JMC Patrick Square, a single-story project in Clemson, the small-scale production builder wanted to increase their level of energy efficiency beyond their current green building practices, including bringing ducts into conditioned space. Through a combination of upgrade measures the team met this goal and achieved many Zero Energy Ready Home requirements. LaFayette Housing Authority undertook a development of 30 affordable rental housing units in 15 duplexes in LaFayette, GA. Because they would be long-term owners, their priorities were low utility bills for the residents and durable, maintainable buildings. The team employed BEopt to optimize buildling envelope and systems choices, including 2x6 advanced framed walls, insulated slab, and heat pump water heater in a utility closet which was ducted to/from an encapsulated attic.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Melt Crystallization of CsF from Alkali Fluorides

Fractional melt-crystallization is a technique used to separate components in a multicomponent liquid mixture through controlled cooling. In fiscal year (FY) 2023, this technique was successfully used to separate CsCl from LiCl-KCl. This demonstrated a potential route for concentrating electrorefiner fission product waste streams in pyrochemical fuel cycles, building on previous work that developed the melt-crystallization system for fission product removal from LiCl-based electrolytes used for oxide reduction. This work investigated whether a thermally controlled process of a solid-liquid separation process could effectively remove CsF from LiF-NaF-KF (FLiNaK)-CsF salt for MSR fuel cycle applications. The designed process aimed to recover purified LiF-NaF-KF salt as solid precipitates while concentrating CsF to a remaining salt heel. This concentrated CsF can then be immobilized during a salt waste stream treatment operation, minimizing waste volume.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Advancing Replicable Solutions for High-Performance Homes in the Southeast - JMC - Patrick Square

The work presented in this report advances the goals of the U.S. Department of Energy Building America program by improving the energy peformance of affordable and market-rate housing. Southface Energy Institute (Southface), part of the U.S. Department of Energy Building America research team Partnership for Home Innovation, worked with owners and builders with various market constraints and ultimate goals for three projects in three climate zones (CZs): Savannah Gardens in Savannah, Georgia (CZ 2); JMC Patrick Square in Clemson, South Carolina (CZ 3); and LaFayette in LaFayette, Georgia (CZ 4). This report documents the design process, computational energy modeling, construction, envelope performance metrics, long-term monitoring results, and successes and failures of the design and execution of these highperformance homes. The JMC Patrick Square project is a single floor with 1,828 ft2 of conditioned living space, three bedrooms, two bathrooms, and an attached two-car garage. This small-scale production builder wanted to increase its level of energy efficiency beyond its current green building practices, including bringing ducts into conditioned space. The team met this goal through a combination of upgrade measures and achieved many Zero Energy Ready Home program requirements. Monitoring the four ducted HPWHs in LaFayette and one in Savannah revealed that HPWH exhaust air impacts attic air during HPWH runtime only, and attic conditions return to previous levels shortly after the HPWH turns off. The HPWH did not appear to impact the loads on the heating and cooling systems, which were also placed in the attic. HPWHs should not be considered dehumidifiers if one is needed in an attic or basement/crawlspace. Ducting the HPWHs did not negatively impact performance compared to other published data of field performance. Changing duct configurations also did not alter the coefficient of performance. HPWHs in efficiency mode (heat pump only) could satisfy hot water demand for most residents. This mode maximizes energy efficiency. Adding .5 in. of insulated sheathing using the Huber ZIP System R Sheathing reduced peak summer temperatures and increased minimum winter temperatures inside the wall assemblies compared to the neighboring home. The neighboring home experienced significantly more risk of condensation and failed the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Standard 160-2009: Criteria for Moisture-Control Design Analysis in Buildings. Despite the fact that energy modeling predicted only a 2% annual savings from the insulated sheathing, preliminary data indicate that reduced heating, ventilating, and air-conditioning runtimes and energy consumption attributed to this measure provide significantly greater savings. Additional research is necessary.

Array↗
NASA NTRS1974

Liquid rocket engine turbopump gears

Design and fabrication of gear drives for rocket engine turbopumps are described in the sequence encountered during the design process as follows: (1) selection of overall arrangement; (2) selection of gear type; (3) preliminary sizing; (4) lubrication system design; (5) detail tooth design; (6) selection of gear materials; and (7) gear fabrication and testing as it affects the design. The description is oriented towards the use of involute spur gears, although reference material for helical gears is also cited.

Source record↗
NASA NTRS1979

Structural dynamics technology research in NASA: Perspective on future needs

The perspective of a NASA ad hoc study group on future research needs in structural dynamics within the aerospace industry is presented. The common aspects of the design process across the industry are identified and the role of structural dynamics is established through a discussion of various design considerations having their basis in structural dynamics. The specific structural dynamics issues involved are identified and assessed as to their current technological status and trends. Projections of future requirements based on this assessment are made and areas of research to meet them are identified.

Source record↗
NASA NTRS1983

Application of 3D aerodynamic/combustion model to combustor primary zone study

A description is provided of the three-dimensional elliptic code for reacting flows used in the combustor design process during the program 'Small Gas Turbine Combustor Primary Zone Study' carried out by a U.S. company. The code, designated MARC-I (multidimensional aerodynamic recirculating combustion-Version I) is an adaptation of the model described by Mongia et al. (1979). The program has the objective to advance the technology of the small reverse-flow annular combustor design through an understanding of primary zone performance factors. The MARC-I code was used for performance predictions of both original designs and later modifications. A test program consisting of both primary zone sampling and overall combustor performance measurements was carried out. It was, therefore, possible to compare the analytical predictions with actual test measurements.

Sullivan, R. E.↗
NASA NTRS1985

Generative engineering databases - Toward expert systems

Engineering data management, incorporating concepts of optimization with data representation, is receiving increasing attention as the amount and complexity of information necessary for performing engineering operations increases and the need to coordinate its representation and use increases. Research in this area promises advantages for a wide variety of engineering applications, particularly those which seek to use data in innovative ways in the engineering process. This paper presents a framework for a comprehensive, relational database management system that combines a knowledge base of design constraints with a database of engineering data items in order to achieve a 'generative database' - one which automatically generates new engineering design data according to the design constraints stored in the knowledge base. The representation requires a database that is able to store all of the data normally associated with engineering design and to accurately represent the interactions between constraints and the stored data while guaranteeing its integrity. The representation also requires a knowledge base that is able to store all the constraints imposed upon the engineering design process.

Rasdorf, W. J.↗
NASA NTRS1987

Fixed order compensator design based on frequency shaped cost functionals

This paper treats the design of fixed order compensators using frequency shaped cost functionals. The formulation is done in an output feedback setting which exploits an observer canonical form to represent the compensator dynamics. The major advantages of the design approach are that the order of the compensator is fixed by the design process, and it is not necessary to realize the frequency shaping dynamics as an integral part of the compensator design. This avoids the two-step approach of full state feedback design followed by the design of an observer, which in the case of a full order observer requires a compensator of order n + nf where n is the order of the plant and nf is the order of the frequency shaping realization. The formulation also precludes the use of direct feedback of the plant output, thus reducing the effect of sensor noise and improving the robustness to high frequency unmodeled dynamics. A structural vibration model describing the fast dynamics of a lightweight flexible arm is used as an example to illustrate the design procedure.

Calise, Anthony J.↗
NASA NTRS1993

Testing self-timed circuits using scan paths

Testing is an essential part of any digital system design and one that can be made much easier if testing is considered during the design process rather than after the system is complete. There are a number of techniques for integrating testability into system design, but many of these traditional testing methods used for synchronous circuits are not directly applicable to non-clocked asynchronous circuits. As a result, many asynchronous circuits do not employ design for testability techniques. A method of using the familiar model of scan paths modified to test self-timed systems are presented. Specifically, circuits designed using a library of self-timed modules to assemble systems with two-phase transition control and bundled data paths are considered. The method involves modifying these self-timed modules such that circuits designed from them have a built-in scan path.

Khoche, Ajay↗
NASA NTRS1988

Auto Design

The 1987 Honda Acura Legend Coupe was designed with aid of the NASA-developed NASTRAN computer program. NASTRAN takes an electronic look at a computerized design and predicts how the structure will react under a great many different conditions. Quick and inexpensive, it minimizes trial and error in the design process and makes possible better, lighter, safer structures while affording significant savings in development time. All Honda auto products designed in the 1980's have been analyzed by the NASTRAN program.

Source record↗
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 NTRS2011

Development of a Piezoelectric Rotary Hammer Drill

The Piezoelectric Rotary Hammer Drill is designed to core through rock using a combination of rotation and high frequency hammering powered by a single piezoelectric actuator. It is designed as a low axial preload, low mass, and low power device for sample acquisition on future missions to extraterrestrial bodies. The purpose of this internship is to develop and test a prototype of the Piezoelectric Rotary Hammer Drill in order to verify the use of a horn with helical or angled cuts as a hammering and torque inducing mechanism. Through an iterative design process using models in ANSYS Finite Element software and a Mason's Equivalent Circuit model in MATLAB, a horn design was chosen for fabrication based on the predicted horn tip motion, electromechanical coupling, and neutral plane location. The design was then machined and a test bed assembled. The completed prototype has proven that a single piezoelectric actuator can be used to produce both rotation and hammering in a drill string through the use of a torque inducing horn. Final data results include bit rotation produced versus input power, and best drilling rate achieved with the prototype.

sampling↗
NASA NTRSDate not supplied

Characterization of Slosh Damping for Ortho-Grid and Iso-Grid Internal Tank Structures

Grid stiffened tank structures such as Ortho-Grid and Iso-Grid are widely used in cryogenic tanks for providing stiffening to the tank while reducing mass, compared to tank walls of constant cross-section. If the structure is internal to the tank, it will positively affect the fluid dynamic behavior of the liquid propellant, in regard to fluid slosh damping. As NASA and commercial companies endeavor to explore the solar system, vehicles will by necessity become more mass efficient, and design margin will be reduced where possible. Therefore, if the damping characteristics of the Ortho-Grid and Iso-Grid structure is understood, their positive damping effect can be taken into account in the systems design process. Historically, damping by internal structures has been characterized by rules of thumb and for Ortho-Grid, empirical design tools intended for slosh baffles of much larger cross-section have been used. There is little or no information available to characterize the slosh behavior of Iso-Grid internal structure. Therefore, to take advantage of these structures for their positive damping effects, there is much need for obtaining additional data and tools to characterize them. Recently, the NASA Marshall Space Flight Center conducted both sub-scale testing and computational fluid dynamics (CFD) simulations of slosh damping for Ortho-Grid and Iso-Grid tanks for cylindrical tanks containing water. Enhanced grid meshing techniques were applied to the geometrically detailed and complex Ortho-Grid and Iso-Grid structures. The Loci-STREAM CFD program with the Volume of Fluid Method module for tracking and locating the water-air fluid interface was used to conduct the simulations. The CFD simulations were validated with the test data and new empirical models for predicting damping and frequency of Ortho-Grid and Iso-Grid structures were generated.

Douglas G. Westra↗
NASA NTRS1999

A Web Based Collaborative Design Environment for Spacecraft

In this era of shrinking federal budgets in the USA we need to dramatically improve our efficiency in the spacecraft engineering design process. We have come up with a method which captures much of the experts's expertise in a dataflow design graph.

collaborative↗
NASA NTRSDate not supplied

Towards Computational Functional Hazard Assessment (CFHA): A Gap Analysis and Concept for Emerging Aviation Systems

Given the current evolution of the National Airspace and future trajectory towards novel and evolving operations with varying levels of autonomy, complexity, and acceptable risk, there is an opportunity to support safety assurance by extending existing methodologies, such as Functional Hazard Assessment (FHA). In response to challenges in performing FHA for novel aviation concepts, we propose a concept for Computational Functional Hazard Assessment (CFHA), which provides processes, methods, and tools for incorporating external data to facilitate further exploration of the hazard space iterativelty throughout the design process. The core components of CFHA involve knowledge capture from historical and operational data, functional architecture specification via a formal modeling language, and simulation for hazardous scenario analysis. Through this concept, we aim to adapt conventional safety assessment to address the increasingly complex hazard space generated from emerging operations.

Seydou Mbaye↗
NASA NTRSDate not supplied

Towards Functional Hazard Assessment (CFHA): A Gap Analysis and Concept for Emerging Aviation Systems

Given the current evolution of the National Airspace and future trajectory towards novel and evolving operations with varying levels of autonomy, complexity, and acceptable risk, there is an opportunity to support safety assurance by extending existing methodologies, such as Functional Hazard Assessment (FHA). In response to challenges in performing FHA for novel aviation concepts, we propose a concept for Computational Functional Hazard Assessment (CFHA), which provides processes, methods, and tools for incorporating external data to facilitate further exploration of the hazard space iterativelty throughout the design process. The core components of CFHA involve knowledge capture from historical and operational data, functional architecture specification via a formal modeling language, and simulation for hazardous scenario analysis. Through this concept, we aim to adapt conventional safety assessment to address the increasingly complex hazard space generated from emerging operations.

Seydou Mbaye↗
DOE OSTI2016

Building America Case Study: Savannah Gardens, Savannah, Georgia

Southface Energy Institute (Southface) partnered with owners and/or builders with various market constraints and ultimate goals for three projects in different climate zones: Savannah, GA (CZ 2), Clemson, SC (CZ 3), and LaFayette, GA (CZ 4). This report documents the design process, computational energy modeling, construction, envelope performance metrics, long-term monitoring results, and successes and failures of the design and execution of these high performance homes. The three bedroom/two bathroom test home in Savannah Gardens on an elevated slab foundation has a semi-conditioned, encapsulated attic. A neighboring home built to EarthCraft specifications was also monitored as a control for exterior foam insulation and a heat pump water heater (HPWH). For the JMC Patrick Square, a single-story project in Clemson, the small-scale production builder wanted to increase their level of energy efficiency beyond their current green building practices, including bringing ducts into conditioned space. Through a combination of upgrade measures the team met this goal and achieved many Zero Energy Ready Home requirements. LaFayette Housing Authority undertook a development of 30 affordable rental housing units in 15 duplexes in LaFayette, GA. Because they would be long-term owners, their priorities were low utility bills for the residents and durable, maintainable buildings. The team employed BEopt to optimize building envelope and systems choices, including 2x6 advanced framed walls, insulated slab, and heat pump water heater in a utility closet which was ducted to/from an encapsulated attic.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Learning nonlinear level sets for dimensionality reduction in function approximation

We developed a Nonlinear Level-set Learning (NLL) method for dimensionality reduction in high-dimensional function approximation with small data. This work is motivated by a variety of design tasks in real-world engineering applications, where practitioners would replace their computationally intensive physical models (e.g., high-resolution fluid simulators) with fast-to-evaluate predictive machine learning models, so as to accelerate the engineering design processes. There are two major challenges in constructing such predictive models: (a) high-dimensional inputs (e.g., many independent design parameters) and (b) small training data, generated by running extremely time-consuming simulations. Thus, reducing the input dimension is critical to alleviate the over-fitting issue caused by data insufficiency. Existing methods, including sliced inverse regression and active subspace approaches, reduce the input dimension by learning a linear coordinate transformation; our main contribution is to extend the transformation approach to a nonlinear regime. Specifically, we exploit reversible networks (RevNets) to learn nonlinear level sets of a high-dimensional function and parameterize its level sets in low-dimensional spaces. A new loss function was designed to utilize samples of the target functions' gradient to encourage the transformed function to be sensitive to only a few transformed coordinates. The NLL approach is demonstrated by applying it to three 2D functions and two 20D functions for showing the improved approximation accuracy with the use of nonlinear transformation, as well as to an 8D composite material design problem for optimizing the buckling-resistance performance of composite shells of rocket inter-stages.

Zhang, Guannan↗