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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Numerical assessment of triply periodic minimal surfaces for direct air capture of carbon dioxide

Direct air capture (DAC) systems often consist of packing material wetted by a capture fluid that reacts with CO 2 in the airstream. The efficiency of the contactor is determined by a complex relationship of fluid dynamics, heat and mass transfer, contactor geometry, and chemical properties. The efficiency of the contactor must be balanced with other factors, primarily pressure drop through the system. Triply periodic minimal surfaces (TPMS) are a class of differential surfaces that have been explored in multiple engineering applications and have been shown to exhibit excellent performance when used in heat exchangers. Their tortuous path provides a high surface-to-volume ratio and favorable trade-off between contact area and pressure drop. In this work, a gyroid-type TPMS contactor was evaluated using computational fluid dynamics for a variety of geometric parameters to explore the potential benefit of TPMS shapes for DAC applications. A thin-film model was employed to model the flow and distribution of the capture solvent, allowing efficient simulations of TPMS structures at scale by eliminating the need for a computationally intensive interface capturing method. A liquid-gas mass transfer model was implemented in the commercial software STAR-CCM+ and used to predict the CO 2 capture efficiency and study the trade-off between capture performance and pressure drop through analysis of capture rates, mass transfer coefficients, and other relevant variables. TPMS contactors with a variety of geometric parameters and two capture solvent options were investigated to determine the effect of design choices on the operational performance of DAC systems. In conclusion, results showed that while contactor geometry is the dominant factor in efficiency and pressure drop, the physiochemical properties of the solvent are an important secondary influence on the contactor performance.

CFD↗
DOE OSTI2022

Centrifuge modeling and numerical analysis on lateral performance of mono-bucket foundation for offshore wind turbines

The lateral loading performance of the mono-bucket foundation for offshore wind turbines is investigated in this study through a series of centrifuge tests and numerical analysis. Six mono-bucket models are considered to assess the influences of aspect ratio under the ultimate condition. The FE model is validated against the centrifuge test results, and the failure mechanism of the foundation is revealed. The parametric study and sensitivity analysis of the soil parameters are performed in the numerical simulations. A modified theoretical calculation method is proposed to estimate the ultimate lateral capacity of the suction bucket foundation by solving the limit equilibrium equations. A correction term is added in the calculation using the “m” method. The position of the rotation center is calculated, demonstrating a better accuracy compared to the previously reported geometric method. The modified calculation method is verified against the field test, the centrifuge test, and the laboratory test. The method is proved to be applicable in estimating the lateral performance of the mono-bucket foundation in a general form. Finally, this study aims to provide well-documented data and design references for practical engineers.

17 WIND ENERGY↗
NASA NTRS1976

The ion-optics of a two-grid electron-bombardment thruster

A detailed experimental investigation was performed to determine the ion-optical performance of an electron-bombardment ion thruster as a function of grid geometry changes. The results show that each geometrical grid parameter independently affects one aspect of ion-optical performance. These observations are used in developing a graphical technique to predict the ion-optical performance of an arbitrary ion source and grid geometry combination. The usefulness of this technique is demonstrated by comparing predicted ion-optical performance of the 30-cm diameter engineering model ion thruster with independent experimental determinations. Good agreement is shown between predicted and experimental results.

Aston, G.↗
NASA NTRS2020

Design Factors for Two-Dimensional, External-Compression Supersonic Inlets

Geometric and aerodynamic design factors were studied for the design of two-dimensional, external-compression inlets operating at a freestream Mach number of Mach 1.7. Computational simulations of the inlet flows were performed to obtain the inlet performance metrics consisting of the inlet flow rates, total pressure recovery, and total pressure distortion at the engine face. The key design factors identified included the external diffuser Mach number, cowl lip interior angle, bleed slot length, throat section aft centerbody slope, and subsonic diffuser length. Using the results of the Mach 1.7 inlet study, inlets were designed for Mach 1.4 and 2.0. The results provide useful insight on the significance of the design factors for the design of such inlets for commercial supersonic aircraft.

Slater, John W.↗
DOE OSTI2026

Enabling the Broader Use of MOOSE for Nuclear Energy and Other Simulation

This Final Scientific and Technical Report summarizes work performed under the Phase IIA SBIR project “Enabling the Broader Use of MOOSE for Nuclear Energy and Other Simulation” (DE-SC0020906) from August 2023 through August 2025. The objective of the Phase IIA effort was to mature and harden capabilities developed during Phase II, with the goal of enabling practical interoperability between Coreform’s isogeometric analysis (IGA) technologies and the Multiphysics Object-Oriented Simulation Environment (MOOSE), while improving robustness, performance, and scalability for complex, nuclear-relevant geometries. Over the course of Phase IIA, the project established and validated an extraction-based interoperability pathway between Coreform tools and MOOSE. A combined mesh and matrix format was defined collaboratively with MOOSE developers and integrated into the solver, enabling standard MOOSE workflows to operate on data exported from Coreform’s IGA and Flex Representation Method (FRM) pipelines. Early demonstrations validated architectural compatibility using linear solid mechanics problems, while later efforts focused on benchmark testing and external use. By the end of the project period, engineers at BWXT were able to independently set up and execute a simulation using the Coreform–MOOSE workflow and provide direct feedback that informed further refinement. In parallel, substantial effort was devoted to improving the robustness of trimmed U-spline construction for complex CAD geometries. A growing test suite of nuclear-relevant models was compiled through collaboration with multiple stakeholders and used to drive extensive bug fixing and reliability improvements. These efforts resulted in improved robustness and performance, including the addition of fallback capabilities that enhance reliability when the underlying commercial CAD kernel fails. Performance-oriented work progressed later in the project, with the development and demonstration of methods to decompose complex geometries into structured subregions and updated data representations to support more efficient solver processing. Additionally, extensive enhancements to threadsafe parallel data structures and trimming operations established a foundation for scalable processing of large assemblies. Collaboration with Sandia National Laboratories on the SGM geometric modeling kernel advanced to a functioning interface test case, positioning the workflow for future kernel integration. Overall, the Phase IIA effort successfully transitioned the project from architectural proof-of-concept to externally exercised, solver-integrated capability, while clarifying remaining technical challenges related to standardization, performance optimization, and kernel integration.

42 ENGINEERING↗
DOE OSTI2021

Parameters of fast and high-yield InAs/GaAs quantum dot semiconductor scintillator

InAs quantum dots (QDs) embedded into a waveguiding GaAs semiconductor matrix may produce scintillation detectors with exceptional speed and yield, making them valuable for nuclear security, medical imaging, and high energy physics applications. In this work, we developed thick (~25 μm) epitaxial heterostructres with high luminescence efficiency composed of self-assembled nano-engineered InAs QDs grown by molecular beam epitaxy. Here, the bulk GaAs acts as a stopping material for incident particles and as a waveguide when layer-transferred onto a low-index substrate. Waveguiding and self-absorption (< 1 cm –1 ) were studied using photoluminescence with scanning laser excitation and modeled with ray optics approximation and geometrical coupling of high-index waveguide to a collection fiber. Scintillating signals from α-particles were analyzed with an external photodiode (PD) and an integrated PD which provided an improved optical coupling. The mean charge collected by the integrated PD corresponded to 3 × 10 4 photoelectrons per 1 MeV of deposited energy, or ~13% of the theoretically achievable light yield. Combined with the previously measured QD scintillation time of 0.3-0.6 ns, this makes the InAs/GaAs QD heterostructures the fastest high yield scintillation material reported.

36 MATERIALS SCIENCE↗
NASA NTRS1973

Assessment of jets as acoustic shields by comparison of single- and multitube suppressor nozzle data

Recent 1/4 scale and engine size nozzle acoustic data, for both 37-tube and single nozzles, were used to test the jet-shielding principle. At low jet velocities the multitube nozzle total sound power approaches the equivalent of 37 single tubes (no shielding), while near-sonic and above, the small equivalent number of single tubes compares well with a geometric model of lateral radiation from only about a third of the circumference of the outer jets (nearly complete shielding). At high jet velocities, the geometric shielding hypothesis is in excellent agreement with acoustic data from which the downstream coalesced jet noise is excluded. Present results are compared with an existing correlation for single jets, and with previous publications on multijet shielding.

Gray, V. H.↗
NASA NTRS1973

Assessment of jets as acoustic shields by comparison of single- and multitube suppressor nozzle data

Recent 1/4 scale and engine size nozzle acoustic data, for both 37-tube and single nozzles, are used to test the jet-shielding principle. At low jet velocities the multitube nozzle total sound power approaches the equivalent of 37 single tubes (no shielding), while near-sonic and above, the small equivalent number of single tubes compares well with a geometric model of lateral radiation from only about a third of the circumference of the outer jets (nearly complete shielding). At high jet velocities, the geometric shielding hypothesis is in excellent agreement with acoustic data from which the downstream coalesced jet-noise is excluded. Present results are compared with an existing correlation for single jets, and with previous publications on multijet shielding.

Gray, V. H.↗
NASA NTRS1977

Application of the TRPLT1 element to large amplitude free vibrations of plates

A finite element formulation is developed for analyzing large amplitude free flexural vibrations of thin plates in NASTRAN. Stress distributions in the plate, in addition to deflection shapes and nonlinear frequencies are determined. Linearized equations of motion governing large amplitude oscillations of plates and a linearized geometrical stiffness matrix are presented. The solution procedure and convergence characteristics are discussed. The quasi-linear geometrical stiffness matrix for an eighteen degree-of-freedom higher order triangular plate element is evaluated by using a seven-point numerical integration. Nonlinear frequencies for square, rectangular, rhombic, and isosceles triangular plates, with edges simply supported or clamped, are compared with earlier solutions. The present formulation is found to give results entirely adequate for engineering purposes.

Mei, C.↗
NASA NTRS2002

A "Tread" Ahead of the Competition

Through a consortium formed by NASA's Glenn Research Center and the Great Lakes Industrial Technology Center, Goodyear acquired a software use agreement for NASA's Micromechanics Analysis Code (MAC), in an effort to design stronger and safer tires. Based on the Generalized Method of Cells micromechanics methodology, the MAC technology has allowed Goodyear scientists and engineers to perform structural analysis of composite laminates for tires all in one step, rather than the several steps previously required. Currently, the MAC code can be used to assess and optimize composite laminates; set cord-spacing guidelines (the diameter and distance between cords may impact the overall durability of a tire); explain structural impact of geometrical configurations; and compare the behavior of the different wire constructions that make up a tire. Furthermore, the MAC software contains a built-in material database and several representative volume elements for a wider choice of composites to better represent the plies and belts in a tire. The end result of the process ultimately reduces the time spent on building, testing, and adjusting tires.

Source record↗
NASA NTRSDate not supplied

Nuclear Thermal Propulsion Material Trade for Additively Manufactured Regenerative Chambers

Nuclear thermal propulsion (NTP) is a game changing technology with advantages over chemical propulsion systems for deep space missions but comes with many engineering challenges. This paper focuses on the challenge of material selection for a regeneratively-cooled chamber for use in a nuclear environment with minimal design margins. Chemical compatibility with reactants and products following energy extraction (be it through combustion or neutron bombardment) must be considered. Similarly, mechanical and thermophysical properties (e.g., density, thermal conductivity, yield strength, etc.) as functions of temperature are critical. While hydrogen embrittlement environment (HEE) is a risk and consideration for traditional chemical combustion chambers, application in a nuclear thermal engine adds additional material compatibility and resilience requirements to long-term nuclear radiation exposure. Chamber materials in this trade included, but were not limited to, A-286, Haynes 230, Haynes 282, CRES 347, GRCop-42, GRCop-84, Inconel 625, JBK-75, and NASA HR-1. The material trade focuses on modern additive manufacturing techniques and hypothetical geometric constraints.

Nuclear Thermal Propulsion↗
NASA NTRSDate not supplied

Nuclear Thermal Propulsion Material Trade for Additively Manufactured Regenerative Chambers

Nuclear thermal propulsion (NTP) is a game changing technology with advantages over chemical propulsion systems for deep space missions but comes with many engineering challenges. This paper focuses on the challenge of material selection for a regeneratively-cooled chamber for use in a nuclear environment with minimal design margins. Chemical compatibility with reactants and products following energy extraction (be it through combustion or neutron bombardment) must be considered. Similarly, mechanical and thermophysical properties (e.g., density, thermal conductivity, yield strength, etc.) as functions of temperature are critical. While hydrogen embrittlement environment (HEE) is a risk and consideration for traditional chemical combustion chambers, application in a nuclear thermal engine adds additional material compatibility and resilience requirements to long-term nuclear radiation exposure. Chamber materials in this trade included, but were not limited to, A-286, Haynes 230, Haynes 282, CRES 347, GRCop-42, GRCop-84, Inconel 625, JBK-75, and NASA HR-1. The material trade focuses on modern additive manufacturing techniques and hypothetical geometric constraints.

Nuclear Thermal Propulsion↗
NASA NTRS1984

The virtual front end: Towards better management of solid geometric data

Throughout the last decade, Computer Aided Design was seen as a Great Promise. Much was accomplished, but that pales in comparison with what was promised. Ultimate achievement has always seemed just a step away. During the era of the early turnkey system, the one step was limited by modeling geometry through a wire frame. Besides being cumbersome to deal with in three dimensions, it was continually shown that a wire frame is ambiguous. This made the modeling of geometry for engineering purposes even more frustrating. The fundamentals of computer aided engineering design rest on the ability to do various analyses. Presently, solid modeling is taking the mechanical engineering CAD world by storm. There are no fewer than 20 solid modeling packages around the world, and more appearing with each vendor show. The question of integration, that is, the combination of elements of the CAD process into unified and easily usable design tools still exists.

Charlesworth, W. W.↗
NASA NTRS1975

Use of graphics in the design office at the Military Aircraft Division of the British Aircraft Corporation

The CAD/CAM interactive computer graphics system was described; uses to which it has been put were shown, and current developments of the system were outlined. The system supports batch, time sharing, and fully interactive graphic processing. Engineers using the system may switch between these methods of data processing and problem solving to make the best use of the available resources. It is concluded that the introduction of on-line computing in the form of teletypes, storage tubes, and fully interactive graphics has resulted in large increases in productivity and reduced timescales in the geometric computing, numerical lofting and part programming areas, together with a greater utilization of the system in the technical departments.

Coles, W. A.↗
NASA NTRS1987

Combustion characteristics of gas turbine alternative fuels

An experimental investigation was conducted to obtain combustion performance values for specific heavyend, synthetic hydrocarbon fuels. A flame tube combustor modified to duplicate an advanced gas turbine engine combustor was used for the tests. Each fuel was tested at steady-state operating conditions over a range of mass flow rates, fuel-to-air mass ratio, and inlet air temperatures. The combustion pressure, as well as the hardware, were kept nearly constant over the program test phase. Test results were obtained in regards to geometric temperature pattern factors as a function of combustor wall temperatures, the combustion gas temperature, and the combustion emissions, both as affected by the mass flow rate and fuel-to-air ratio. The synthetic fuels were reacted in the combustor such that for most tests their performance was as good, if not better, than the baseline gasoline or diesel fuel tests. The only detrimental effects were that at high inlet air temperature conditions, fuel decomposition occurred in the fuel atomizing nozzle passages resulting in blockage. And the nitrogen oxide emissions were above EPA limits at low flow rate and high operating temperature conditions.

Rollbuhler, R. James↗
NASA NTRS2003

Imparting Desired Attributes by Optimization in Structural Design

Commonly available optimization methods typically produce a single optimal design as a Constrained minimum of a particular objective function. However, in engineering design practice it is quite often important to explore as much of the design space as possible with respect to many attributes to find out what behaviors are possible and not possible within the initially adopted design concept. The paper shows that the very simple method of the sum of objectives is useful for such exploration. By geometrical argument it is demonstrated that if every weighting coefficient is allowed to change its magnitude and its sign then the method returns a set of designs that are all feasible, diverse in their attributes, and include the Pareto and non-Pareto solutions, at least for convex cases. Numerical examples in the paper include a case of an aircraft wing structural box with thousands of degrees of freedom and constraints, and over 100 design variables, whose attributes are structural mass, volume, displacement, and frequency. The method is inherently suitable for parallel, coarse-grained implementation that enables exploration of the design space in the elapsed time of a single structural optimization.

Sobieszczanski-Sobieski, Jaroslaw↗
NASA NTRS2012

Development of Modeling Capabilities for Launch Pad Acoustics and Ignition Transient Environment Prediction

This paper presents development efforts to establish modeling capabilities for launch vehicle liftoff acoustics and ignition transient environment predictions. Peak acoustic loads experienced by the launch vehicle occur during liftoff with strong interaction between the vehicle and the launch facility. Acoustic prediction engineering tools based on empirical models are of limited value in efforts to proactively design and optimize launch vehicles and launch facility configurations for liftoff acoustics. Modeling approaches are needed that capture the important details of the plume flow environment including the ignition transient, identify the noise generation sources, and allow assessment of the effects of launch pad geometric details and acoustic mitigation measures such as water injection. This paper presents a status of the CFD tools developed by the MSFC Fluid Dynamics Branch featuring advanced multi-physics modeling capabilities developed towards this goal. Validation and application examples are presented along with an overview of application in the prediction of liftoff environments and the design of targeted mitigation measures such as launch pad configuration and sound suppression water placement.

West, Jeff↗