Search NASA⌕ Search

SEARCH · Search NASA

Results for “selective heating”

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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2005

Finite Element Analysis of Adaptive-Stiffening and Shape-Control SMA Hybrid Composites

Shape memory alloy hybrid composites with adaptive-stiffening or morphing functions are simulated using finite element analysis. The composite structure is a laminated fiber-polymer composite beam with embedded SMA ribbons at various positions with respect to the neutral axis of the beam. Adaptive stiffening or morphing is activated via selective resistance heating of the SMA ribbons or uniform thermal loads on the beam. The thermomechanical behavior of these composites was simulated in ABAQUS using user-defined SMA elements. The examples demonstrate the usefulness of the methods for the design and simulation of SMA hybrid composites. Keywords: shape memory alloys, Nitinol, ABAQUS, finite element analysis, post-buckling control, shape control, deflection control, adaptive stiffening, morphing, constitutive modeling, user element

Gao, Xiujie↗
NASA NTRS2010

Initial Assessment of a Rapid Method of Calculating CEV Environmental Heating

An innovative method for rapidly calculating spacecraft environmental absorbed heats in planetary orbit is described. The method employs reading a database of pre-calculated orbital absorbed heats and adjusting those heats for desired orbit parameters. The approach differs from traditional Monte Carlo methods that are orbit based with a planet centered coordinate system. The database is based on a spacecraft centered coordinated system where the range of all possible sun and planet look angles are evaluated. In an example case 37,044 orbit configurations were analyzed for average orbital heats on selected spacecraft surfaces. Calculation time was under 2 minutes while a comparable Monte Carlo evaluation would have taken an estimated 26 hours

Pickney, John T.↗
NASA NTRS2019

On-Demand Non-Contact Distillation: Low-g Demonstrations of a Leidenfrost Waste-Water Processor

Leidenfrost phenomenon is employed as a potential solution to NASA’s urine water recovery problem by providing a method for on demand non-contact distillation. Leidenfrost investigations have been almost exclusively conducted in terrestrial environments and are in turn largely defined by the ever-presence of gravity. In this work we demonstrate a variety of Leidenfrost effects for enormous liquid droplets in the microgravity environment of a 2.1 second drop tower. Dynamic Leidenfrost droplet impacts on a selection of heated hydrophilic and superhydrophobic surfaces in microgravity are presented. Nearly ideal elastic non- contact impacts and droplet oscillation modes are observed. Impact experiments are extended to a variety of heated substrates including macro pillar arrays, confined passageways, and others. The potential for contamination-free processing is obvious, with the proof of concept to be pursued shortly.

Leidenfrost↗
DOE OSTI2020

Nanofibrous electrocatalyst including nanofibrous continuous network of graphitic nanofibers having embedded catalytically active metal moieties

A nanofibrous catalyst and method of manufacture. A precursor solution of a transition metal based material is formed into a plurality of interconnected nanofibers by electro-spinning the precursor solution with the nanofibers converted to a catalytically active material by a heat treatment. Selected subsequent treatments can enhance catalytic activity.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Molten fluid electrode apparatus

A battery includes negative electrode material and positive electrode material where the materials are in a solid phase except for selected portions that are heated to transform the selected portions into a fluid. The fluid portion of negative electrode material is directed to a negative electrode region of a reaction chamber and the fluid portion of positive electrode material is directed to a positive electrode region of the reaction chamber where a solid electrolyte containing ions of the negative electrode separates the positive electrode region from the negative electrode region.

Vissers, Daniel R.↗
DOE OSTI2022

Selective Thermal Emission with Radiation and Adsorption in Annuli (STERADIAN): An Advanced Heat Exchanger Concept for Supercritical CO 2 Power Cycles

One of the key limitations affecting ability to achieve the efficiency and cost saving advantages of a supercritical CO 2 (scCO 2 ) power cycle resides with the primary heat exchanger where costs can exceed 50% of the plant capital budget depending on design. This project established the foundational groundwork for a new type of heat exchanger optimized to take advantage of radiative heat transfer to scCO 2 . Selective thermal emission coatings were designed and tested that radiated more light tuned to the 4.2 µm infrared absorption band of CO 2 . Coating design utilized principles of nanophotonic bandgap theory to design a selective emitter that has: 1) low emissivity in the visible band, 2) near 100% effective emissivity in the mid-IR wavelength between 4 and 4.5 µm wavelength, and 3) strong suppression of far-IR light emission that will maximize radiative heat transfer efficiency to scCO 2 . Computational fluid dynamics simulations show that an advanced heat exchanger implementing this selective thermal emitter coating is 25 to as much as 40% smaller than conventional heat exchanger designs.

14 SOLAR ENERGY↗
DOE OSTI2023

Thermal Integration of DETAIL Systems

A thermal connection between the Microreactor AGile Non-nuclear Experimental Testbed (MAGNET) and the thermal energy distribution system (TEDS) has been a key part of the Dynamic Energy Transport and Integration Laboratory (DETAIL) plan since the development of the Integrated Energy Systems Roadmap in 2020. This connection provides an expanding demonstration capability for integrated system operations. The thermal connection between MAGNET and TEDS required the selection of a heat exchanger and valves to isolate flow. Research staff within the NEET Crosscutting Technology Development program selected equipment after receiving proposals from multiple vendors. A helical coil heat exchanger from Graham Corporation was selected for its small volume relative to its heat transfer surface area to fit in the limited space available. Triple offset butterfly valves with pneumatic actuators from Flowserve were selected to isolate and/or control flow of the hot gas through the heat exchanger. Staff from Idaho National Laboratory’s (INL) Facilities and Site Services Engineering department designed the piping and structural support. A mechanical construction firm was contracted to install the system. This report documents the design and construction of this thermal connection.

25 ENERGY STORAGE↗
NASA NTRS1984

Thermal management considerations for 100 kW(e) In-Core Thermionic Space Nuclear Power System

The general thermal management approach for the SP-100 In-Core Thermionic Space Nuclear Power System is presented. Thermal advantages and design features of the heat transport subsystem are addressed, including the selection of parameters, heat transport fluid, and materials. Pumping considerations, thermal insulation requirements, and radiator design are discussed, and the impacts of system scaling to higher power levels are projected.

Van Hagan, T. H.↗
NASA NTRS2001

Thermostructural Analysis of Unconventional Wing Structures of a Hyper-X Hypersonic Flight Research Vehicle for the Mach 7 Mission

Heat transfer, thermal stresses, and thermal buckling analyses were performed on the unconventional wing structures of a Hyper-X hypersonic flight research vehicle (designated as X-43) subjected to nominal Mach 7 aerodynamic heating. A wing midspan cross section was selected for the heat transfer and thermal stress analyses. Thermal buckling analysis was performed on three regions of the wing skin (lower or upper); 1) a fore wing panel, 2) an aft wing panel, and 3) a unit panel at the middle of the aft wing panel. A fourth thermal buckling analysis was performed on a midspan wing segment. The unit panel region is identified as the potential thermal buckling initiation zone. Therefore, thermal buckling analysis of the Hyper-X wing panels could be reduced to the thermal buckling analysis of that unit panel. "Buckling temperature magnification factors" were established. Structural temperature-time histories are presented. The results show that the concerns of shear failure at wing and spar welded sites, and of thermal buckling of Hyper-X wing panels, may not arise under Mach 7 conditions.

Ko, William L.↗
NASA NTRS2012

Joule-Heated Molten Regolith Electrolysis Reactor Concepts for Oxygen and Metals Production on the Moon and Mars

The maturation of Molten Regolith Electrolysis (MRE) as a viable technology for oxygen and metals production on explored planets relies on the realization of the self-heating mode for the reactor. Joule heat generated during regolith electrolysis creates thermal energy that should be able to maintain the molten phase (similar to electrolytic Hall-Heroult process for aluminum production). Self-heating via Joule heating offers many advantages: (1) The regolith itself is the crucible material, it protects the vessel walls (2) Simplifies the engineering of the reactor (3) Reduces power consumption (no external heating) (4) Extends the longevity of the reactor. Predictive modeling is a tool chosen to perform dimensional analysis of a self-heating reactor: (1) Multiphysics modeling (COMSOL) was selected for Joule heat generation and heat transfer (2) Objective is to identify critical dimensions for first reactor prototype.

Sibille, Laurent↗
NASA NTRS1987

Measurement of heat and moisture fluxes at the top of the rain forest during ABLE

Observations are presented of turbulent heat, moisture, and momentum transport made at two levels, approximately 5 and 10 m above the Amazon rain forest canopy. Data acquired at 10 Hz included variances and some mixed third moments of vertical velocity, temperature, and humidity. Two features of the data appear to question the displacement height hypothesis: (1) The characteristic dissipation length scale in the near-canopy layer varied between 20 m in stable conditions to approximately 150 m during afternoon convective conditions, generally larger scales than would be expected; and (2) No appreciable difference in dissipation scales was seen at the two observed levels. Observed peaks in vertical velocity-temperature cospectra lead to similar length scale estimates for dominant eddies. Heat budgets on selected days show that frequent periods with negative heat flux concurrent with continuing positive moisture flux occur in early afternoon, and this is believed to indicate the patchy nature of canopy-atmosphere coupling. Vertical velocity skewness was observed to be negative on three successive days and exhibited a sharp positive gradient.

Fitzjarrald, David R.↗
NASA NTRS1988

Turbulent transport observed just above the Amazon forest

Observations of turbulent heat, moisture, and momentum transport made at two levels, approximately 5 and 10 m above the Amazon rain forest canopy, are presented. Data acquired at 10 Hz included variances and some mixed third moments of vertical velocity, temperature, and humidity. Two features of the data appear to question the displacement height hypothesis: (1) the characteristic dissipation length scale in the near-canopy layer varied between 20 m in stable conditions to approximately 150 m during afternoon convective conditions, generally larger scales than would be expected, and (2) no appreciable differences in dissipation scales was seen at two observed levels. Heat budgets on selected days show that frequent periods with negative heat flux concurrent with continuing positive moisture flux occur in early afternoon, and this is believed to indicate the patchy nature of canopy-atmosphere coupling. Vertical velocity skewness was observed to be negative on three successive days and exhibited a sharp positive gradient. Time series of some of the terms in the turbulence budgets of vertical velocity variance and kinematic heat flux are presented.

Fitzjarrald, David R.↗
DOE OSTI2021

Numerical study to predict the effect of surface roughness on the thermal and hydraulic performance of additively manufactured heat exchangers

Heat exchangers are used in many industries to transfer thermal energy between two or more objects with an associated thermal and hydraulic performance indicated by thermal effectiveness and pressure drop respectively. Many investigations have aimed to enhance the thermal effectiveness of heat exchangers by introducing turbulent flow inducers that increase the heat transfer rate at the expense of increasing pressure drop. Flow inducers like surface roughness can be controlled with advanced manufacturing methods like additive manufacturing for heat exchanger production. Selecting and manufacturing an optimal surface roughness for heat exchangers requires a more comprehensive approach that accounts for the surface roughness effect on the thermal and hydraulic performance of a sample. Since fabricating samples with additive manufacturing to a desired surface roughness can be an extensive experimental process, this study will fundamentally investigate the effect of surface roughness on the thermal and velocity boundary layers for various surface roughness profiles with physics-based computational modeling. To accurately model the surface roughness effect on thermohydraulic performance, correlations like roughness ratio, friction factor, and Nusselt number are investigated. This study expects to indicate correlations for different flow regimes which can successfully predict the effect of surface roughness on thermohydraulic performance. Results generated from modeling surface roughness effect with unique correlations are then compared to experimental data obtained from literature for validation. The results of this study will provide insight to understand the thermal fluid physics associated with surface roughness and design guidelines for heat exchangers produced with additive manufacturing.

36 MATERIALS SCIENCE↗
NASA NTRS2003

Current Developments in Future Planetary Probe Sensors for TPS

In-situ Thermal Protection System (TPS) sensors are required to provide traceability of TPS performance and sizing tools. Traceability will lead to higher fidelity design tools, which in turn will lead to lower design safety margins, and decreased heatshield mass. Decreasing TPS mass will enable certain missions that are not otherwise feasible, and directly increase science payload. NASA Ames is currently developing two flight measurements as essential to advancing the state of TPS traceability for material modeling and aerothermal simulation: heat flux and surface recession (for ablators). The heat flux gage is applicable to both ablators and non-ablators and is therefore the more generalized sensor concept of the two with wider applicability to mission scenarios. This paper describes the development of a microsensor capable of surface and in-depth temperature and heat flux measurements for TPS materials appropriate to Titan, Neptune, and Mars aerocapture, and direct entry. The thermal sensor will be monolithic solid state devices composed of thick film platinum RTD on an alumina substrate. Choice of materials and critical dimensions are used to tailor gage response, determined during calibration activities, to specific (forebody vs. aftbody) heating environments. Current design has maximum operating temperature of 1500 K, and allowable constant heat flux of q=28.7 watts per square centimeter, and time constants between 0.05 and 0.2 seconds. The catalytic and radiative response of these heat flux gages can also be changed through the use of appropriate coatings. By using several co-located gages with various surface coatings, data can be obtained to isolate surface heat flux components due to radiation, catalycity and convection. Selectivity to radiative heat flux is a useful feature even for an in-depth gage, as radiative transport may be a significant heat transport mechanism for porous TPS materials in Titan aerocapture. This paper also reports on progress to adapt a previously flown surface recession sensor, based on the Jupiter probe Galileo Analog Resistance Ablation Detector (ARAD), to appropriate aerocapture conditions.

Martinez, Ed↗
NASA NTRS2005

Development of Solid State Thermal Sensors for Aeroshell TPS Flight Applications

In-situ Thermal Protection System (TPS) sensors are required to provide verification by traceability of TPS performance and sizing tools. Traceability will lead to higher fidelity design tools, which in turn will lead to lower design safety margins, and decreased heatshield mass. Decreasing TPS mass will enable certain missions that are not otherwise feasible, and directly increase science payload. NASA Ames is currently developing two flight measurements as essential to advancing the state of TPS traceability for material modeling and aerothermal simulation: heat flux and surface recession (for ablators). The heat flux gage is applicable to both ablators and non-ablators and is therefore the more generalized sensor concept of the two with wider applicability to mission scenarios. This paper describes the continuing development of a thermal microsensor capable of surface and in-depth temperature and heat flux measurements for TPS materials appropriate to Titan, Neptune, and Mars aerocapture, and direct entry. The thermal sensor is a monolithic solid state device composed of thick film platinum RTD on an alumina substrate. Choice of materials and critical dimensions are used to tailor gage response, determined during calibration activities, to specific (forebody vs. aftbody) heating environments. Current design has maximum operating temperature of 1500K, and allowable constant heat flux of q=28.7 W/cm(sup 2), and time constants between 0.05 and 0.2 seconds. The catalytic and radiative response of these heat flux gages can also be changed through the use of appropriate coatings. By using several co-located gages with various surface coatings, data can be obtained to isolate surface heat flux components due to radiation, catalycity and convection. Selectivity to radiative heat flux is a useful feature even for an in-depth gage, as radiative transport may be a significant heat transport mechanism for porous TPS materials in Titan aerocapture.

Martinez, Ed↗
NASA NTRS1972

ASRDI oxygen technology survey. Volume 3: Heat transfer and fluid dynamics. Abstracts of selected technical reports and publications

Selected information is presented from an assemblage of reports and publications on heat transfer and fluid dynamics with direct applicability to oxygen systems. For each document cited, an abstract has been prepared together with key words and a listing of most important references found in the document. Additionally, an author index, a subject index, and a key word index have been provided to simplify the retrieval of specific information from this work. In each subject area - e.g., boiling heat transfer - the individual citations are listed alphabetically by first author, with review papers dually noted under the appropriate subject category and under review papers. Of the documents reviewed and evaluated for inclusion in this publication, coverage of existing information directly concerned with oxygen was given primary emphasis. However, work not specifically oxygen-designated but considered applicable to oxygen by the reviewer e.g., a two-phase friction factor correlation derived from nitrogen experiments is occasionally given where no actual oxygen data exist, as an aid to the reader. Approximately 130 abstracts are listed.

Schmidt, A. F.↗