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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS2018

Thermal Assessment of Paraffin Phase Change Material Mini-Packs on IceCube 3U CubeSat in Flight

Three paraffin phase change material (PCM) mini-packs were flown on the IceCube instrument in the International Space Station (ISS) orbit. They contained a total of 40.69 g of n-Hexadecane. In flight, from Day of Year (DOY) 250-255 in 2017, the IceCube instrument operation scheme was "Day-On Every Other Orbit." The instrument power-on time was approximately 45.6 minutes longer than the design power-on time. Its power-off time was 47 minutes longer than the design power-off time. Flight temperature telemetry data revealed that latent heat change of the paraffin PCM maintained the instrument temperatures at about 18 degrees Centigrade most of the time. It validated the functionality of the paraffin PCM mini-packs.

Paraffin phase change material; CubeSat; latent he↗
NASA NTRS2016

Subscale Water Based Phase Change Material Heat Exchanger Development

Supplemental heat rejection devices are required in many spacecraft as the radiators are not sized to meet the full heat rejection demand. One means of obtaining additional heat rejection is through the use of phase change material heat exchangers (PCM HX's). PCM HX's utilize phase change to store energy in unfavorable thermal environments (melting) and reject the energy in favorable environments (freezing). Traditionally, wax has been used as a PCM on spacecraft. However, water is an attractive alternative because it is capable of storing about 40% more energy per unit mass due to its higher latent heat of fusion. The significant problem in using water as a PCM is its expansion while freezing, leading to structural integrity concerns when housed in an enclosed heat exchanger volume. Significant investigation and development has taken place over the past five years to understand and overcome the problems associated with water PCM HX's. This paper reports on the final efforts by Johnson Space Center's Thermal Systems Branch to develop a water based PCM HX. The test article developed and reported on is a subscale version of the full-scale water-based PCM HX's constructed by Mezzo Technologies. The subscale unit was designed by applying prior research on freeze front propagation and previous full-scale water PCM HX development. Design modifications to the subscale unit included use of urethane bladder, decreased aspect ratio, perforated protection sheet, and use of additional mid-plates. Testing of the subscale unit was successful and 150 cycles were completed without fail.

Sheth, Rubik↗
NASA NTRS1989

Prediction of thermal-stress and deformations due to phase change in solidifying objects via flux/stress based finite element representations

The paper presents numerical simulations for the prediction of thermal-stress and deformation fields resulting from phase change in solidifying bodies employing new finite element representations. The formulations herein demonstrated provide different perspectives and physical interpretation for the modeling/analysis of thermo-mechanical problems and possess several inherent advantages. In comparison to traditional approaches for solving similar problems, the paper employs new flux/stress based representations to enhance the overall effectiveness. Comparative numerical applications validate applicability of the formulations for predicting the temperature induced deformations and stresses resulting from effects due to phase change.

Tamma, K. K.↗
NASA NTRS1996

Coupled Structural, Thermal, Phase-Change and Electromagnetic Analysis for Superconductors

Described are the theoretical development and computer implementation of reliable and efficient methods for the analysis of coupled mechanical problems that involve the interaction of mechanical, thermal, phase-change and electromagnetic subproblems. The focus application has been the modeling of superconductivity and associated quantum-state phase-change phenomena. In support of this objective the work has addressed the following issues: (1) development of variational principles for finite elements, (2) finite element modeling of the electromagnetic problem, (3) coupling of thermal and mechanical effects, and (4) computer implementation and solution of the superconductivity transition problem. The main accomplishments have been: (1) the development of the theory of parametrized and gauged variational principles, (2) the application of those principled to the construction of electromagnetic, thermal and mechanical finite elements, and (3) the coupling of electromagnetic finite elements with thermal and superconducting effects, and (4) the first detailed finite element simulations of bulk superconductors, in particular the Meissner effect and the nature of the normal conducting boundary layer. The theoretical development is described in two volumes. This volume, Volume 1, describes mostly formulations for specific problems. Volume 2 describes generalization of those formulations.

Felippa, C. A.↗
DOE OSTI2025

Tunable phase-change metasurfaces coupled with mid-infrared molecular vibrations

Chiral optical metasurfaces have emerged as a promising platform in coupling with molecular vibrational fingerprints through the enhanced light-matter interaction under different circularly polarized light illumination. Here, this work reports the mode coupling between the mid-infrared phonon vibrations of polymethyl methacrylate (PMMA) molecules and the thermally tunable chiral metasurfaces based on the phase-change material Ge₂Sb₂Te₅ (GST-225). Phase-change chiral metasurfaces with high circular dichroism (CD) in absorption and tunable plasmonic resonance in the frequency range of 48–56 THz are demonstrated, which covers the phonon vibrational frequency of PMMA molecules at 52 THz. The mode splitting features are observed in the absorption and CD spectra when the metasurface resonance is tuned across the phonon vibrational frequency of PMMA molecules during the phase transition of GST-225. The underlying mechanism of molecule-metasurface coupling is further revealed by studying the electric field and power loss density distributions of the phonon–plasmon coupled modes under both left-handed and right-handed circularly polarized (LCP and RCP) light. The demonstrated results show the potential of dynamically tunable chiral metasurfaces for the applications in label-free molecular sensing, biomedical diagnostics, thermal imaging, and mid-infrared photonics.

Tang, Haotian [Missouri Univ. of Science and Techn↗
NASA NTRS1996

Coupled Structural, Thermal, Phase-change and Electromagnetic Analysis for Superconductors, Volume 2

Described are the theoretical development and computer implementation of reliable and efficient methods for the analysis of coupled mechanical problems that involve the interaction of mechanical, thermal, phase-change and electromag subproblems. The focus application has been the modeling of superconductivity and associated quantum-state phase change phenomena. In support of this objective the work has addressed the following issues: (1) development of variational principles for finite elements, (2) finite element modeling of the electromagnetic problem, (3) coupling of thermel and mechanical effects, and (4) computer implementation and solution of the superconductivity transition problem. The main accomplishments have been: (1) the development of the theory of parametrized and gauged variational principles, (2) the application of those principled to the construction of electromagnetic, thermal and mechanical finite elements, and (3) the coupling of electromagnetic finite elements with thermal and superconducting effects, and (4) the first detailed finite element simulations of bulk superconductors, in particular the Meissner effect and the nature of the normal conducting boundary layer. The theoretical development is described in two volumes. Volume 1 describes mostly formulation specific problems. Volume 2 describes generalization of those formulations.

Felippa, C. A.↗
NASA NTRS1987

Thermally induced phase changes, lateral heterogeneity of the mantle, continental roots, and deep slab anomalies

Factors which influence the lateral heterogeneity in density and seismic velocity with depth in the upper earth mantle are discussed. It is emphasized that most of the increases in density and seismic velocity with depth are caused by pressure-induced solid-solid phase changes in the high-density high-velocity phases of mineral assemblage, due to variations in temperature. In particular, the ilmenite form of MgSiO3 and the gamma-spinel form of Mg2SiO4 have broad stability fields in cold mantle and are not stable in hotter mantle. It is emphasized that the density and velocity anomalies associated with temperature-induced phase changes in mineral assemblage must be taken into account in the thermal models of the slabs; when these effects are accounted for, the geoid and seismic anomalies associated with subducted slabs are consistent with slab confinement to the upper mantle and with layered models of mantle convection.

Anderson, Don L.↗
NASA NTRS1988

Fluoride salts as phase change materials for thermal energy storage in the temperature range 1000-1400 K

Eutectic compositions and congruently melting intermediate compounds in binary and ternary fluoride salt systems were characterized for potential use as latent heat of fusion phase change materials to store thermal energy in the temperature range 1000-1400 K. The melting points and eutectic compositions for many systems with published phase diagrams were experimentally verified and new eutectic compositions having melting points between 1000 and 1400 K were identified. Heats of fusion of several binary and ternary eutectics and congruently melting compounds were experimentally measured by differential scanning calorimetry. For a few systems in which heats of mixing in the melts have been measured, heats of fusion of the eutectics were calculated from thermodynamic considerations and good agreement was obtained between the measured and calculated values. Several combinations of salts with high heats of fusion per unit mass (greater than 0.7 kJ/g) have been identified for possible use as phase change materials in advanced solar dynamic space power applications.

Misra, Ajay K.↗
NASA NTRS1993

Coupled structural, thermal, phase-change and electromagnetic analysis for superconductors, volume 1

This research program has dealt with the theoretical development and computer implementation of reliable and efficient methods for the analysis of coupled mechanical problems that involve the interaction of mechanical, thermal, phase-change and electromagnetic subproblems. The focus application has been the modeling of superconductivity and associated quantum-state phase-change phenomena. In support of this objective the work has addressed the following issues: (1) development of variational principles for finite elements; (2) finite element modeling of the electromagnetic problem; (3) coupling of thermal and mechanical effects; and (4) computer implementation and solution of the superconductivity transition problem. The research was carried out over the period September 1988 through March 1993. The main accomplishments have been: (1) the development of the theory of parametrized and gauged variational principles; (2) the application of those principled to the construction of electromagnetic, thermal and mechanical finite elements; and (3) the coupling of electromagnetic finite elements with thermal and superconducting effects; and (4) the first detailed finite element simulations of bulk superconductors, in particular the Meissner effect and the nature of the normal conducting boundary layer. The grant has fully supported the thesis work of one doctoral student (James Schuler, who started on January 1989 and completed on January 1993), and partly supported another thesis (Carmelo Militello, who started graduate work on January 1988 completing on August 1991). Twenty-three publications have acknowledged full or part support from this grant, with 16 having appeared in archival journals and 3 in edited books or proceedings.

Felippa, Carlos A.↗
NASA NTRS1980

Phase changes in liquid face seals

Computer program predicts boiling (phase change) in liquid face seals. Program determines if and when boiling occurs, and calculates location of boiling interface, pressure and temperature profiles, and load.

Hughes, W. F.↗
NASA NTRS1991

Parametric studies of phase change thermal energy storage canisters for Space Station Freedom

Phase Change Materials (PCM) canister parametric studies are discussed wherein the thermal-structural effects of changing various canister dimensions and contained PCM mass values are examined. With the aim of improving performance, 11 modified canister designs are analyzed and judged relative to a baseline design using five quantitative performance indicators. Consideration is also given to qualitative factors such as fabrication/inspection, canister mass production, and PCM containment redundancy. Canister thermal analyses are performed using the finite-difference based computer program NUCAM-2DV. Thermal-stresses are calculated using closed-form solutions and simplifying assumptions. Canister wall thickness, outer radius, length, and contained PCM mass are the parameters considered for this study. Results show that singular canister design modifications can offer improvements on one or two performance indicators. Yet, improvement in one indicator is often realized at the expense of another. This confirms that the baseline canister is well designed. However, two alternative canister designs, which incorporate multiple modifications, are presented that offer modest improvements in mass or thermal performance, respectively.

Kerslake, Thomas W.↗
NASA NTRS1993

Kodak phase-change media for optical tape applications

The SbInSn phase-change write-once optical medium developed by Eastman Kodak Company is particularly suitable for development into the next generation optical tape media. Its performance for optical recording has already been demonstrated in some of the highest performance optical disk systems. Some of the key performance features are presented.

Tyan, Yuan-Sheng↗
NASA NTRS1974

Lateral conduction effects on heat-transfer data obtained with the phase-change paint technique

A computerized tool, CAPE, (Conduction Analysis Program using Eigenvalues) has been developed to account for lateral heat conduction in wind tunnel models in the data reduction of the phase-change paint technique. The tool also accounts for the effects of finite thickness (thin wings) and surface curvature. A special reduction procedure using just one time of melt is also possible on leading edges. A novel iterative numerical scheme was used, with discretized spatial coordinates but analytic integration in time, to solve the inverse conduction problem involved in the data reduction. A yes-no chart is provided which tells the test engineer when various corrections are large enough so that CAPE should be used. The accuracy of the phase-change paint technique in the presence of finite thickness and lateral conduction is also investigated.

Maise, G.↗
NASA NTRS2004

Phase Change

Recent workshops to define strategic research on critical issues in microgravity fluids and transport phenomena in support of mission orientated needs of NASA and many technical conferences over the years in support of fundamental research targeting NASA's long range missions goal have identified several phase change processes needed to design advanced space and planetary based systems for long duration operations Recommendation noted that phase change processes are profoundly affected by gravitational environment.

Hasan, Mohammad M.↗
DOE OSTI2025

Experimental investigation on phase change material–based finned tube heat exchanger for thermal energy storage and building envelope thermal management

Phase change materials (PCMs) are attractive solutions for thermal energy storage (TES) applications by absorbing and releasing large amounts of latent heat during solid–liquid phase transitions. However, their relatively low thermal conductivity requires novel heat exchanger–based solutions to improve the power density and overall energy storage efficiency of the TES system. This work presents the design and experimental results of a finned tube heat exchanger to store collected natural thermal energy from a building envelope in a latent-based TES and to release it later for building heating/cooling applications. We experimentally evaluate the finned tube heat exchanger and evaluate the performance of TES in reducing building heating and cooling loads over 3–4 h of desired time of operation (e.g., peak load). The optimized design allows for maximum energy density by minimizing the heat exchanger volume, and the system is evaluated experimentally using commercially available heat exchanger materials and an organic PCM. Here, the experimental results reveal that the TES system is able to charge and discharge stored latent energy within 3–4 h, matching peak building electricity demand duration under an average fluid flow rate of 0.136 kg/s and temperature difference of 5.55 °C. Importantly, such optimized designs illuminate a path toward TES designs that are low-cost, scalable, and optimized for thermal energy and power availability under the desired time of operation.

25 ENERGY STORAGE↗