Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “bundle method”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

In-Situ Three-Dimensional Shape Rendering from Strain Values Obtained Through Optical Fiber Sensors

A method and system for rendering the shape of a multi-core optical fiber or multi-fiber bundle in three-dimensional space in real time based on measured fiber strain data. Three optical fiber cores arc arranged in parallel at 120.degree. intervals about a central axis. A series of longitudinally co-located strain sensor triplets, typically fiber Bragg gratings, are positioned along the length of each fiber at known intervals. A tunable laser interrogates the sensors to detect strain on the fiber cores. Software determines the strain magnitude (.DELTA.L/L) for each fiber at a given triplet, but then applies beam theory to calculate curvature, beading angle and torsion of the fiber bundle, and from there it determines the shape of the fiber in s Cartesian coordinate system by solving a series of ordinary differential equations expanded from the Frenet-Serrat equations. This approach eliminates the need for computationally time-intensive curve-tilting and allows the three-dimensional shape of the optical fiber assembly to be displayed in real-time.

Chan, Hon Man↗
DOE OSTI2024

Design and Manufacturing of High Performance, Reduced Charge Heat Exchangers

Air-to-fluid heat exchangers (HXs) play a critical role as the main heat transfer component in Heating, Ventilation, Air-Conditioning, and Refrigeration (HVAC&R) systems. However, their airside thermal resistance significantly inhibits their overall performance. Furthermore, these HXs must be continually more compact to meet the latest refrigerant charge limits to reduce emissions. Recent literature suggests that traditional HX geometries (e.g., round or flat tubes with fins), have reached their limits, and more sophisticated shape- and topology-optimized designs are required to achieve the next jump in performance. This research sheds light on the next generation of air-to-refrigerant HXs and aims to address several practical issues to commercialization such as novelty challenges (improved performance for significant charge reduction; modeling expertise & time investment), manufacturing challenges (non-round tube manufacturing; tube-header integration; product qualification, e.g., burst pressure testing, extreme operational environment, etc.), and operational challenges (flow maldistribution, fouling & wetting, noise & vibration). For example, a >20% improvement on one (or more) HX-level performance metrics (e.g., envelope volume, airside pressure drop, face area, capacity, refrigerant charge, weight, cost, etc.) must be achieved before a HX design is considered for commercialization. We present a new, comprehensive and experimentally validated air-to-refrigerant HX optimization framework with simultaneous thermal-hydraulic performance and mechanical strength considerations for novel, non-round, shape- and topology-optimized tubes capable of optimizing single and two-phase HX designs for any refrigerant choice and performance requirement with significant engineering time savings compared to conventional design practices. The framework was exercised for a wide range of applications and refrigerants, resulting in HXs which achieved greater than 20% improved performance, 20% reductions in size, and 25% reductions in refrigerant charge. To enable non-round tube bundle use in next generation HVAC&R equipment, novel manufacturing techniques were investigated, including the development of conventional manufacturing methods for small diameter, non-round tubes and novel tube-header integration strategies. In total, ten HX prototypes were manufactured, nine using conventional methods directly attributed to this project and one using advanced additive manufacturing methods. The five-year manufacturing feasibility of the proposed HXs was found to have a good outlook. The non-round tube HX simulated performance was validated through comprehensive experimental testing, including nine in-house component-level tests, one independent component-level test at an industry partner laboratory, and in-house system-level tests of using a commercially-available, residential packaged A/C unit which was retrofitted with a non-round tube prototype HX. It was found that HX designs proposed by the new framework can successfully predict experimental thermal-hydraulic performance within ±10-20% the first time with no manual design changes, eliminating the need for time-consuming and expensive prototyping efforts. This work will accelerate design and time to market for next generation HXs while simultaneously facilitating industry transition to new refrigerants at lower charge.

42 ENGINEERING↗
DOE OSTI2024

Anomalies of 4d SpinG theories

Abstract We consider ’t Hooft anomalies of four-dimensional gauge theories whose fermion matter content admits Spin G (4) generalized spin structure, withGeither gauged or a global symmetry. We discuss methods to directly computew 2 ∪w 3 ’t Hooft anomalies involving Stiefel-Whitney classes of gauge and flavor symmetry bundles that such theories can have on non-spin manifolds, e.g.M 4 = ℂℙ 2 . Such anomalies have been discussed for SU(2) gauge theory with adjoint fermions, where they were shown to give an effect that was originally found in the Donaldson-Witten topological twist of$$ \mathcal{N} $$ N = 2 SYM theory. We directly compute these anomalies for a variety of theories, including generalGgauge theories with adjoint fermions, SU(2) gauge theory with fermions in general representations, and Spin(N) gauge theories with fundamental matter. We discuss aspects of matching these and other ’t Hooft anomalies in the IR phase where global symmetries are spontaneously broken, in particular for generalG gauge theory withN f adjoint Weyl fermions. For example, in the case ofN f = 2 we discuss anomaly matching in the IR phase consisting of$$ {h}_{G_{\textrm{gauge}}}^{\vee } $$ h G gauge ∨ copies of a ℂℙ 1 non-linear sigma model, including for thew 2 w 3 anomalies when formulated with$$ {\textrm{Spin}}_{\textrm{SU}{(2)}_{\textrm{global}}}(4) $$ Spin SU 2 global 4 structure.

Physics↗
NASA NTRS1989

Calculation of turbulence-driven secondary motion in ducts with arbitrary cross section

Calculation methods for turbulent duct flows are generalized for ducts with arbitrary cross-sections. The irregular physical geometry is transformed into a regular one in computational space, and the flow equations are solved with a finite-volume numerical procedure. The turbulent stresses are calculated with an algebraic stress model derived by simplifying model transport equations for the individual Reynolds stresses. Two variants of such a model are considered. These procedures enable the prediction of both the turbulence-driven secondary flow and the anisotropy of the Reynolds stresses, in contrast to some of the earlier calculation methods. Model predictions are compared to experimental data for developed flow in triangular duct, trapezoidal duct and a rod-bundle geometry. The correct trends are predicted, and the quantitative agreement is mostly fair. The simpler variant of the algebraic stress model procured better agreement with the measured data.

Demuren, A. O.↗
NASA NTRS1990

Calculation of turbulence-driven secondary motion in ducts with arbitrary cross-section

Calculation methods for turbulent duct flows are generalized for ducts with arbitrary cross-sections. The irregular physical geometry is transformed into a regular one in computational space, and the flow equations are solved with a finite-volume numerical procedure. The turbulent stresses are calculated with an algebraic stress model derived by simplifying model transport equations for the individual Reynolds stresses. Two variants of such a model are considered. These procedures enable the prediction of both the turbulence-driven secondary flow and the anisotropy of the Reynolds stresses, in contrast to some of the earlier calculation methods. Model predictions are compared to experimental data for developed flow in triangular duct, trapezoidal duct and a rod-bundle geometry. The correct trends are predicted, and the quantitative agreement is mostly fair. The simpler variant of the algebraic stress model procured better agreement with the measured data.

Demuren, A. O.↗
NASA NTRS1998

Improved Electroformed Structural Copper and Copper Alloys

Electroforming offers a superior means for fabricating internally cooled heat exchangers and structures subjected to thermal environments. Copper is deposited from many such applications because of the good thermal conductivity. It suffers from mediocre yield strength as a structural material and loses mechanical strength at intermediate temperatures. Mechanical properties similar to those of electroformed nickel are desired. Phase 1 examined innovative means to improve deposited copper structural performance. Yield strengths as high as 483 MPa (70 ksi) were obtained with useful ductility while retaining a high level of purity essential to good thermal conductivity. Phase 2 represents a program to explore new additive combinations in copper electrolytes to produce a more fine, equiaxed grain which can be thermally stabilized by other techniques such as alloying in modest degrees and dispersion strengthening. Evaluation of new technology - such as the codeposition of fullerness (diamond-like) particles were made to enhance thermal conductivity in low alloys. A test fire quality tube-bundle engine was fabricated using these copper property improvement concepts to show the superiority of the new coppers and fabrications methods over competitive technologies such as brazing and plasma deposition.

Malone, G. A.↗
DOE OSTI2021

Air Dehumidification using Ionic Liquid-Based Fiber Bundle Membrane Contactor

Air dehumidification is essential since excess moisture in the buildings causes discomfort to the occupants, encourages the production of air pathogens such as mold or mildew, and causes corrosion and rotting that degrade building materials. Existing moisture removal processes are mainly focused on condensation and desiccant (liquid or solid) techniques with direct contact between air and desiccant. However, these methods are energy-intensive, or desiccant might be lost or cause corrosion in the process. The main objective of this study is to investigate an ionic liquid-based liquid desiccant absorber based on a membrane fiber bundle. The novel system consists of membrane contactors containing bundles of 10,000 polypropylene fibers. The fiber bundles have 0.3 micron diameter, with ionic liquid flowing inside, and air flowing outside. The fibers provide a high contact area among phases: 1.4 m2 contact surface area in a 0.00015 m3 volume. The ionic liquid as a sorbent stipulates the selectivity for air, prevents the loss of solvent in the operation due to negligible volatility, provides fast diffusion due to low viscosity compared to common ionic liquids, and has high affinity and solubility in water. The dehumidification capacity of the membrane technology was experimentally investigated. The experimental results show that the ionic-liquid based membrane system can effectively remove excess moisture from the air. The novel fiber bundle dehumidification system has a system volume of 0.00798 m3 (7.98 L) and active heat and mass transfer surface area of 8.4 m2. It achieved an average dehumidification of 320 ± 25 W with a volumetric air flowrate of 3.1 m3/min (108 ft3/min).

Turnaoglu, Tugba↗
DOE OSTI2023

High-Fidelity Numerical Investigation on Elucidating Sodium Heat Transfer Characteristics for 37-Pin Wire-Wrapped Fuel Bundle in the PLANDTL Facility

This study involved a Reynolds-averaged Navier-Stokes- (RANS-) based computational fluid dynamics (CFD) analysis of the 37-pin wire-wrapped fuel bundle of the PNC Plant dynamics test loop (PLANDTL) facility. Previously, mainly the hydrodynamic phenomena of the wire-wrapped fuel bundle were analyzed, but the present study additionally included heat transfer analysis through conjugate heat transfer. The main purpose of the study was to benchmark the experimental data of the PLANDTL 37-pin wire-wrapped fuel bundle to investigate the heat transfer phenomena. In addition, the aim was to verify the accuracy of the RANS-based CFD analysis method using the STAR-CCM+ simulation software in comparison with the experimental data. The grid used for verification was an innovative grid system consisting of hexahedra using Fortran-based code. The development of the RANS-based CFD methodology included grid sensitivity analysis, turbulence model sensitivity analysis, and turbulent Prandtl number sensitivity analysis. Information on the temperature, mass flow rate, and area of the CFD results for each subchannel was provided for the top of the heated section and is expected to serve as a reference for future studies aiming to perform the validation and verification of a PLANDTL facility. In addition, the dependence of the peak temperature on the azimuth angle of each pin was analyzed.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2026

Extension of Clad Damage Propagation Model for Fission Gas Dispersal and Two-Phase Flow Effects in MOOSE SubChannel Module

This report presents an extension of the Clad Damage Propagation (CDAP) model implemented in the MOOSE SubChannel Module (SCM) to capture post-failure fission-gas dispersal and two-phase flow effects in sodium-cooled fast reactor assemblies. The extended model tracks discharged gas axially and radially, computes channel-averaged flow quality and void fraction using a Lockhart–Martinelli framework, evaluates two-phase frictional pressure-drop multipliers, determines inlet mass-flow degradation under fixed core pressures, and applies an intensified-void-based heat-transfer degradation to affected fuel pins. Radial plume expansion is parameterized using mineral-oil jet experiments mapped to sodium conditions via Reynolds–Weber similarity. Implementation details are documented, along with the new methods and user inputs needed to control plume mapping and two-phase behavior. Demonstration simulations for 19- and 37-pin bundles show that breach size and inlet velocity strongly influence propagation potential: small breaches (≤0.5 mm) produce limited degradation while larger breaches (~1 mm) can drive oscillatory temperature spikes and enhanced failure propagation, especially at higher velocities. These results demonstrate that the extended CDAP model provides a more complete framework for quantifying cladding damage propagation and evaluating propagation potential in transient scenarios. The approach remains computationally efficient, consistent with subchannel-level analysis, yet incorporates sufficient physics to bridge localized post-failure effects with bundle- and assembly-scale degradation.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS2016

Development of a High Performance, Low Profile Translation Table with Wire Feedthrough for a Deep Space CubeSat

NEAScout, a 6U cubesat and secondary payload on NASA's EM-1, will use an 85 sq m solar sail to travel to a near-earth asteroid at about 1 Astronomical Unit (about 1.5 x 10(exp 8) km) for observation and reconnaissance1. A combination of reaction wheels, reaction control system, and a slow rotisserie roll about the solar sail's normal axis were expected to handle attitude control and adjust for imperfections in the deployed sail during the 2.5-year mission. As the design for NEAScout matured, one of the critical design parameters, the offset in the center of mass and center of pressure (CP/CM offset), proved to be sub-optimal. After significant mission and control analysis, the CP/CM offset was accommodated by the addition of a new subsystem to NEAScout. This system, called the Active Mass Translator (AMT), would reside near the geometric center of NEAScout and adjust the CM by moving one portion of the flight system relative to the other. The AMT was given limited design space - 17 mm of the vehicle's assembly height-and was required to generate +/-8 cm by +/-2 cm translation to sub-millimeter accuracy. Furthermore, the design must accommodate a large wire bundle of small gage, single strand wire and coax cables fed through the center of the mechanism. The bend radius, bend resistance, and the exposure to deep space environment complicates the AMT design and operation and necessitated a unique design to mitigate risks of wire bundle damage, binding, and cold-welding during operation. This paper will outline the design constraints for the AMT, discuss the methods and reasoning for design, and identify the lessons learned through the designing, breadboarding and testing for the low-profile translation stages with wire feedthrough capability.

Few, Alex↗
NASA NTRS2016

Development of a High Performance, Low-Profile Translation Table with Wire Feedthrough

NEAScout, a 6U cubesat, will use an 85 sq m solar sail to travel to a near-earth asteroid for observation. Over the course of the 3-year mission, a combination of reaction wheels, cold gas reaction control system, and a slow rotisserie roll about the solar sail's normal axis were expected to handle attitude control and adjust for imperfections in the deployed sail. As the design for NEAScout matured, one of the critical design parameters, the offset in the center of mass and center of pressure (CP/CM offset), proved to be sub-optimal. After significant mission and control analysis, the CP/CM offset was addressed and a new subsystem was introduced to NEAScout. This system, called the Active Mass Translator (AMT), would reside near the geometric center of NEAScout and adjust the CM by moving one portion of the flight system relative to the other. The AMT was given limited design space-about 17 mm of the vehicle's assembly height-and was required to generate +/-10 cm by +/-5 cm translation to sub-millimeter accuracy. Furthermore, the design must accommodate a large wire bundle of small gage, single strand wire and coax cables fed through the center of the mechanism. The bend radius, bend resistance, and the exposure to deep space environment complicates the AMT design and operation and necessitated a unique design to mitigate risks of wire bundle damage, binding, and cold-welding during operation. This paper will outline the design constraints for the AMT, discuss the methods and reasoning for design, and identify the lessons learned through the design downselect process and breadboarding for designing low-profile translation stages with feedthrough capabilities.

Few, Alex↗
NASA NTRS2016

Development of a High-Performance, Low-Profile Translation Table with Wire Feedthrough for a Deep Space CubeSat

NEAScout, a 6U cubesat and secondary payload on NASA's EM-1, will use an 85 sq m solar sail to travel to a near-earth asteroid at about 1 Astronomical Unit (about 1.5 x 10(exp 8) km) for observation and reconnaissance1. A combination of reaction wheels, reaction control system, and a slow rotisserie roll about the solar sail's normal axis were expected to handle attitude control and adjust for imperfections in the deployed sail during the 2.5-year mission. As the design for NEAScout matured, one of the critical design parameters, the offset in the center of mass and center of pressure (CP/CM offset), proved to be sub-optimal. After significant mission and control analysis, the CP/CM offset was accommodated by the addition of a new subsystem to NEAScout. This system, called the Active Mass Translator (AMT), would reside near the geometric center of NEAScout and adjust the CM by moving one portion of the flight system relative to the other. The AMT was given limited design space - 17 mm of the vehicle's assembly height-and was required to generate +/-8 cm by +/-2 cm translation to sub-millimeter accuracy. Furthermore, the design must accommodate a large wire bundle of small gage, single strand wire and coax cables fed through the center of the mechanism. The bend radius, bend resistance, and the exposure to deep space environment complicates the AMT design and operation and necessitated a unique design to mitigate risks of wire bundle damage, binding, and cold-welding during operation. This paper will outline the design constraints for the AMT, discuss the methods and reasoning for design, and identify the lessons learned through the designing, breadboarding and testing for the low-profile translation stages with wire feedthrough capability.

Few, Alex↗
DOE OSTI2020

Bis-polymer lipid-peptide conjugates and nanoparticles thereof

The present invention provides bis-polymer lipid-peptide conjugates containing a hydrophobic block and headgroup containing a helical peptide and two polymer blocks. The conjugates can self-assemble to form helix bundle subunits, which in turn assemble to provide micellar nanocarriers for drug cargos and other agents. Particles containing the conjugates and methods for forming the particles are also disclosed.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Full Length Assembly Testing in PELICAN (Final Report)

In support of the development of the U.S. Department of Energy (DOE) Versatile Test Reactor (VTR), a thermal hydraulics test facility was constructed to generate experimental measurement of the pressure drop across a single full-scale assembly containing prototypic axial reflectors, fuel, and plena components. Constructed and operated at Argonne National Laboratory, the Pressure drop Experimental Loop for Investigations of Core Assemblies in Nuclear reactors (PELICAN) facility was designed to achieve hydraulic conditions identical to those anticipated for a full-scale fuel assembly located in the VTR core in the region with the highest flow rate. Using water as surrogate for liquid sodium, the flow loop was operated at elevated temperatures and pressures to match the thermophysical properties of liquid sodium and ensure matching Reynolds and Euler numbers. The measurement objectives for data generated from this test facility was driven primarily by the validation needs for code calculations and simulations of the reference VTR core. These objectives focused on the need to validate pressure drop results across the various segments of the fuel assembly as they relate directly to the pumping power and safety of the reactor. Presented in this report are experimental results and analytical comparisons based on testing of a full-length assembly in PELICAN. Housed within a hexagonal test section extending 3.4 m in length, the tested assembly features a prototypic lower reflector, grid plates, wire-wrapped rod bundle, upper reflector, and exit region. The rod bundle extends over 1.5 m in length and contains 217 individual wire-wrapped rods with dimensions that best reflect the reference VTR design. The as-tested bundle assembly was fabricated using 316 stainless steel 0.25-inch (6.35-mm) diameter rods wrapped with 0.04-inch (1.016-mm) diameter wire at a helical pitch of 10.51 inch (26.6 cm). Details of the method for in-house wire-wrapping, assembly, and installation are provided later in this report. Experimental measurements of pressure drop at 19 positions along the test assembly were recorded for a range of flow conditions, with special attention paid to key locations within the assembly, including component inlet and outlet, transition, and wire-wrapped rod bundle regions. Testing conditions were based on 110°C water with flow rates ranging from 50 to 450 GPM (3 to 27 kg/s) at the inlet of the test assembly generating Reynolds numbers and velocities up to ~8.0×10 4 and ~7.8 m/s, respectively, within the rod bundle region. Non-dimensional values for the friction factor were then calculated based on these experimental measurements and compared against those predicted by various analytical correlations available from open literature. Predictions by the upgraded Cheng and Todreas, Rehme, and Novendstern correlations fell within 4% to those values measured experimentally.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
NASA NTRS1971

Plate measurement techniques and reduction methods used by the West German satellite observers, and resulting consequences for the observation

The West German tracking stations are equipped with ballistic cameras. Plate measurement and plate reduction must therefore follow photogrammetric methods. Approximately 100 star positions and 200 satellite positions are measured on each plate. The mathematical model for spatial rotation of the bundle of rays is extended by including terms for distortion and internal orientation of the camera as well as by providing terms for refraction which are computed for the measured coordinates of the star positions on the plate. From the measuring accuracy of the plate coordinates it follows that the timing accuracy for the exposures has to be about one millisecond, in order to obtain a homogeneous system.

Deker, H.↗
NASA NTRS1976

Laser fiber optics ordnance initiation system

Recent progress on system development in the laser initiation of explosive devices is summarized. The topics included are: development of compact free-running mode and Q-switched lasers, development of low-loss fiber optic bundles and connectors, study of nuclear radiation effects on the system, characterization of laser initiation sensitivities of insensitive high explosives, and the design methods used to achieve attractive system weight and cost savings. Direction for future work is discussed.

Yang, L. C.↗
NASA NTRS2023

Application of Fountain Code to High-Rate Delay Tolerant Networks

Space communication poses several unique challenges that are not always present in typical terrestrial communications. Currently, communication with satellites is based on point-to-point links, and development of an interplanetary internet is an active research area. Delay Tolerant Networking (DTN) has been proposed as a way to mitigate the long delays and disruptions found in deep space. A specialized version of DTN, called High-rate Delay Tolerant Networking (HDTN), has been developed by NASA to support a variety of missions requiring store-and-forward capability. However, there are still several features that are desired for HDTN including data fragmentation, multicast, and anycast. This project proposes the application of fountain code in HDTN as a means of fragmenting, distributing, and reassembling data (in the form of bundles) across multiple nodes (i.e. satellites) to any number of receivers (i.e. ground stations). Fountain code is shown to be a promising encoding method for use with the HDTN protocol suite due to its short runtimes, small encoded file sizes, and loss tolerance.

Noah Douglass↗
DOE OSTI2022

Ultrahigh strength, modulus, and conductivity of graphitic fibers by macromolecular coalescence

Theoretical considerations suggest that the strength of carbon nanotube (CNT) fibers be exceptional; however, their mechanical performance values are much lower than the theoretical values. To achieve macroscopic fibers with ultrahigh performance, we developed a method to form multidimensional nanostructures by coalescence of individual nanotubes. The highly aligned wet-spun fibers of single- or double-walled nanotube bundles were graphitized to induce nanotube collapse and multi-inner walled structures. These advanced nanostructures formed a network of interconnected, close-packed graphitic domains. Their near-perfect alignment and high longitudinal crystallinity that increased the shear strength between CNTs while retaining notable flexibility. The resulting fibers have an exceptional combination of high tensile strength (6.57 GPa), modulus (629 GPa), thermal conductivity (482 W/m·K), and electrical conductivity (2.2 MS/m), thereby overcoming the limits associated with conventional synthetic fibers.

36 MATERIALS SCIENCE↗