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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Li-Ion Battery Thermal Characterization for Thermal Management Design

Battery design efforts often prioritize enhancing the energy density of the active materials and their utilization. However, optimizing thermal management systems at both the cell and pack levels is also key to achieving mission-relevant battery design. Battery thermal management systems, responsible for managing the thermal profile of battery cells, are crucial for balancing the trade-offs between battery performance and lifetime. Designing such systems requires accounting for the multitude of heat sources within battery cells and packs. This paper provides a summary of heat generation characterizations observed in several commercial Li-ion battery cells using isothermal battery calorimetry. The primary focus is on assessing the impact of temperatures, C-rates, and formation cycles. Moreover, a module-level characterization demonstrated the significant additional heat generated by module interconnects. Characterizing heat signatures at each level helps inform manufacturing at the design, production, and characterization phases that might otherwise go unaccounted for at the full pack level. Further testing of a 5 kWh battery pack revealed that a considerable temperature non-uniformity may arise due to inefficient cooling arrangements. To mitigate this type of challenge, a combined thermal characterization and multi-domain modeling approach is proposed, offering a solution without the need for constructing a costly module prototype.

25 ENERGY STORAGE↗
DOE OSTI2022

A High-Throughput MEMS-Based Differential Scanning Calorimeter for Direct Thermal Characterization of Antibodies

Calorimeters, which can be used for rapid thermal characterization of biomolecules, are getting intense attention in drug development. This paper presents a novel MEMS-based differential scanning calorimeter (DSC) for direct thermal characterization of protein samples. The DSC consisted of a pair of temperature sensors made by vanadium oxide (VOx) film with a temperature coefficient of resistivity of –0.025/K at 300 K, a microfluidic device with high thermal insulation (2.8 K/mW), and a Peltier heater for linear temperature scanning. The DSC exhibited high sensitivity (6.1 µV/µW), low noise (0.4 µW), high scanning rate (45 K/min), and low sample consumption volume (0.63 µL). The MEMS DSC was verified by measuring the temperature-induced denaturation of lysozyme at different pH, and then used to study the thermal stability of a monoclonal antibody (mAb), an antigen-binding fragment (Fab), and a dual variable domain immunoglobulin (DVD-Ig) at pH = 6. The results showed that lysozyme is a stable protein in the pH range of 4.0–8.0. The protein stability study revealed that the transition temperatures of the intact Fab fragment, mAb, and DVD proteins were comparable with conformational stability results obtained using conventional commercial DSC. These studies demonstrated that the MEMS DSC is an effective tool for directly understanding the thermal stability of antibodies in a high-throughput and low-cost manner compared to conventional calorimeters.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2015

Non-Contact Thermal Characterization of NASA's HERMeS Hall Thruster

The thermal characterization test of NASA's 12.5-kW Hall Effect Rocket with Magnetic Shielding has been completed. This thruster was developed to support a number of potential Solar Electric Propulsion Technology Demonstration Mission concepts, including the Asteroid Redirect Robotic Mission concept. As a part of the preparation for this characterization test, an infrared-based, non-contact thermal imaging system was developed to measure the temperature of various thruster surfaces that are exposed to high voltage or plasma. An in-situ calibration array was incorporated into the setup to improve the accuracy of the temperature measurement. The key design parameters for the calibration array were determined in a separate pilot test. The raw data from the characterization test was analyzed though further work is needed to obtain accurate anode temperatures. Examination of the front pole and discharge channel temperatures showed that the thruster temperature was driven more by discharge voltage than by discharge power. Operation at lower discharge voltages also yielded more uniform temperature distributions than at higher discharge voltages. When operating at high discharge voltage, increasing the magnetic field strength appeared to have made the thermal loading azimuthally more uniform.

Hall Thrusters↗
NASA NTRS1972

Thermal characterization of reusable external insulation for the space shuttle.

Thermal protection systems utilizing reusable ceramic external insulations are under study for application to the orbiter vehicle of NASA's space shuttle system which is to be launched by an expendable booster, remain in orbit for a week or two, reenter the earth's atmosphere, and land like a conventional aircraft. The required reuse capability is for 100 missions. The thermal characterization of the reusable external insulation (REI) is described. Thermal conductivity measurements are described for a series of mullite-based REIs with densities ranging from 100 to 300 kg/cu m, including opacified variations of the mullite material designed for reduction of the radiant component of heat transport. The results of thermal conductivity measurements performed on guarded-hot-plate equipment from 150 to above 1200 K in different vacuum and gaseous environments are described. Measurements were also made with exceptionally large temperature differences to detect transparency effects in the unopacified REIs. These measurements were made to provide design data for the flight conditions, and to aid in theoretical computations aimed at separating and optimizing the heat transport components.

Brazel, J. P.↗
NASA NTRS2015

Non-Contact Thermal Characterization of NASA's HERMeS Hall Thruster

The Thermal Characterization Test of NASAs 12.5-kW Hall thruster is being completed. This thruster is being developed to support of a number of potential Solar Electric Propulsion Technology Demonstration Mission concepts, including the Asteroid Redirect Robotic Mission concept. As a part of this test, an infrared-based, non-contact thermal imaging system was developed to measure Hall thruster surfaces that are exposed to high voltage or harsh environment. To increase the accuracy of the measurement, a calibration array was implemented, and a pilot test was performed to determine key design parameters for the calibration array. The raw data is analyzed in conjunction with a simplified thermal model of the channel to account for reflection. The reduced data will be used to refine the thruster thermal model, which is critical to the verification of the thruster thermal specifications. The present paper will give an overview of the decision process that led to identification of the need for a non-contact temperature diagnostic, the development of said diagnostic, the measurement results, and the simplified thermal model of the channel.

Electric Propulsion↗
NASA NTRS1998

Thermal Characterization of a Direct Gain Solar Thermal Engine

A thermal/fluids analysis of a direct gain solar thermal upper stage engine is presented and the results are discussed. The engine has been designed and constructed at the NASA Marshall Space Flight Center for ground testing in a facility that can provide about 10 kilowatts of concentrated solar energy to the engine. The engine transfers that energy to a coolant (hydrogen) that is heated and accelerated through a nozzle to produce thrust. For the nominal design values and a hydrogen flowrate of 2 lb/hr., the results of the analysis show that the hydrogen temperature in the chamber (nozzle entrance) reaches about 3800 F after 30 minutes of heating and about 3850 F at steady-state (slightly below the desired design temperature of about 4100 F). Sensitivity analyses showed these results to be relatively insensitive to the values used for the absorber surface infrared emissivity and the convection coefficient within the cooling ducts but very sensitive to the hydrogen flowrate. Decreasing the hydrogen flowrate to 1 lb/hr. increases the hydrogen steady-state chamber temperature to about 4700 F, but also causes an undesirable decrease in thrust.

Alexander, Reginald A.↗
NASA NTRS1999

Thermal Characterization of a Direct Gain Solar Thermal Engine

A thermal/fluids analysis of a direct gain solar thermal upper stage engine is presented and the results are discussed. The engine was designed and constructed at the NASA Marshall Space Flight Center for ground testing in a facility that can provide about 10 kilowatts of concentrated solar energy to the engine. The engine transfers energy to a coolant (hydrogen) that is heated and accelerated through a nozzle to produce thrust. For the nominal design values and a hydrogen flowrate of 2 lb./hr., the results of the analysis show that the hydrogen temperature in the chamber (nozzle entrance) reaches about 3800 F after 30 minutes of heating and about 3850 F at steady-state (slightly below the desired design temperature of about 4100 F. Sensitivity analyses showed these results to be relatively insensitive to the values used for the absorber surface infrared emissivity and the convection coefficient within the cooling ducts but very sensitive to the hydrogen flowrate. Decreasing the hydrogen flowrate to 1 lb./hr. increases the hydrogen steady-state chamber temperature to about 4700 F, but also of course causes a decrease in thrust.

Alexander, Reginald A.↗
NASA NTRS2001

Thermal Characterization of a NASA 30-cm Ion Thruster Operated up to 5 kW

A preliminary thermal characterization of a newly-fabricated NSTAR-derived test-bed thruster has recently been performed. The temperature behavior of the rare-earth magnets are reported because of their critical impact on thruster operation. The results obtained to date showed that the magnet temperatures did not exceed the stabilization Emit during thruster operation up to 4.6 kW. Magnet temperature data were also obtained for two earlier NSTAR Engineering Model Thrusters and are discussed in this report. Comparison between these thrusters suggests that the test-bed engine in its present condition is able to operate safely at higher power because of the lower discharge losses over the entire operating power range of this engine. However, because of the 'burn-in' behavior of the NSTAR thruster, magnet temperatures are expected to increase as discharge losses increase with accumulated thruster operation. Consequently, a new engineering solution may be required to achieve 5-kW operation with acceptable margin.

SarverVerhey, Timothy R.↗
NASA NTRS1991

Thermal characterization and toughness of ethynyl containing blends

As part of an effort to develop high performance structural resins with an attractive combination of properties for aerospace applications, a series of ethynyl-terminated polysulfones of different molecular weights were prepared and blended with a low molecular weight ethynyl-terminated coreactant. Upon heating above 200 C, these ethynyl containing materials react to form a chain extended and crosslinked network structure. This reaction renders the materials insoluble in common solvents, but also reduces the toughness as compared to high molecular weight linear polysulfones. The thermal characterization of these blends and the toughness of the resulting cured materials are discussed.

Jensen, Brian J.↗
NASA NTRS2013

Performance and Thermal Characterization of the NASA-300MS 20 kW Hall Effect Thruster

NASA's Space Technology Mission Directorate is sponsoring the development of a high fidelity 15 kW-class long-life high performance Hall thruster for candidate NASA technology demonstration missions. An essential element of the development process is demonstration that incorporation of magnetic shielding on a 20 kW-class Hall thruster will yield significant improvements in the throughput capability of the thruster without any significant reduction in thruster performance. As such, NASA Glenn Research Center and the Jet Propulsion Laboratory collaborated on modifying the NASA-300M 20 kW Hall thruster to improve its propellant throughput capability. JPL and NASA Glenn researchers performed plasma numerical simulations with JPL's Hall2De and a commercially available magnetic modeling code that indicated significant enhancement in the throughput capability of the NASA-300M can be attained by modifying the thruster's magnetic circuit. This led to modifying the NASA-300M magnetic topology to a magnetically shielded topology. This paper presents performance evaluation results of the two NASA-300M magnetically shielded thruster configurations, designated 300MS and 300MS-2. The 300MS and 300MS-2 were operated at power levels between 2.5 and 20 kW at discharge voltages between 200 and 700 V. Discharge channel deposition from back-sputtered facility wall flux, and plasma potential and electron temperature measurements made on the inner and outer discharge channel surfaces confirmed that magnetic shielding was achieved. Peak total thrust efficiency of 64% and total specific impulse of 3,050 sec were demonstrated with the 300MS-2 at 20 kW. Thermal characterization results indicate that the boron nitride discharge chamber walls temperatures are approximately 100 C lower for the 300MS when compared to the NASA- 300M at the same thruster operating discharge power.

High power↗
DOE OSTI2023

Mechanical and Thermal Characterization of Phase-Change Material and High-Density Polyethylene Functional Composites for Thermal Energy Storage

Abstract Phase-change materials (PCMs) can be used to develop thermal energy storage systems as they absorb large amount of latent heat nearly at a constant temperature when changing phase from a solid to a liquid. To prevent leakage when in a liquid state, PCM is shape stabilized in a polymer matrix of high-density polyethylene (HDPE). The present research explores the injection-molded mechanical and thermal properties of different PCM/HDPE composite ratios. The tensile strength and modulus of elasticity at room temperature and with the PCM fully melted within the composite are measured. Additionally, the hardness, latent heat of fusion, phase-change temperature, and thermal conductivity are investigated. An analysis of microstructures of the composite is used to support the findings. The PCM within the PCM/HDPE composite gives it the benefit of thermal storage but causes a decrease in mechanical properties.

Energy & Fuels↗
NASA NTRS1986

Quantitative thermal characterization of thin plates

The principles of quantitative thermal testing of the mechanical integrity of platelike structures are discussed. In this technique, a scanned laser pulse is used to inject a thermal pattern in a sample, and a thermal IR imager is used to document the evolution of the pattern subsequent to injection. The measurements are remote, noncontacting, and one-sided, and the algorithms used to obtain diffusivity are all emissivity-independent. The results yielded by application of the three analytical techniques, used to obtain diffusivity values from the image data on stainless steel, a graphite-epoxy composite, brass, and aluminum 2024 samples, are presented.

Welch, C. S.↗
NASA NTRS2019

Electrical and Thermal Characterization of 3D Printed Thermoplastic Parts with Embedded Wires for High Current-Carrying Applications

Fabrication of parts exhibiting multi-functionality has recently been complemented by hybrid polymer extrusion additive manufacturing in combination with wire embedding technology. While much mechanical characterization has been performed on parts produced with fused deposition modeling, limited characterization has been performed when combined electrical and thermal loads are applied to 3D printed multi-material parts. As such, this work describes the design, fabrication, and testing of 3D printed thermoplastic coupons containing embedded copper wires that carried current. An automated fabrication process was used employing a hybrid additive manufacturing machine that dispensed polycarbonate thermoplastic and embedded bare copper wires. Testing included AC and DC hipot testing as well as thermal testing on as-fabricated and heat treated coupons to determine the effect of porosity in the substrate. The heat-treated parts contained reduced amounts of porosity, as corroborated through scanning electron microscopy, which led to 50 % increased breakdown strength and 30 to 40 % increased heat dissipation capabilities. The results of this research are describing a set of design protocol that can be used as a guideline for 3D printed embedded electronics to predict the electrical and thermal behavior.

Hipot testing↗
NASA NTRS2003

Design of Experiments for the Thermal Characterization of Metallic Foam

Metallic foams are being investigated for possible use in the thermal protection systems of reusable launch vehicles. As a result, the performance of these materials needs to be characterized over a wide range of temperatures and pressures. In this paper a radiation/conduction model is presented for heat transfer in metallic foams. Candidates for the optimal transient experiment to determine the intrinsic properties of the model are found by two methods. First, an optimality criterion is used to find an experiment to find all of the parameters using one heating event. Second, a pair of heating events is used to determine the parameters in which one heating event is optimal for finding the parameters related to conduction, while the other heating event is optimal for finding the parameters associated with radiation. Simulated data containing random noise was analyzed to determine the parameters using both methods. In all cases the parameter estimates could be improved by analyzing a larger data record than suggested by the optimality criterion.

Crittenden, Paul E.↗
DOE OSTI2020

Thermal characterization of the build chamber in electron beam melting

Electron beam powder bed fusion, commonly termed electron beam melting (EBM), offers great versatility in multiple-part processes and can produce high quality as-built components due to low residual stresses. The EBM process is complex and requires careful thermal management, including uniform and consistent preheating of the powder bed, in order to ensure quality and consistency of the product. However, most of the simulations in the literature focus on the selective melting stage of the process. As of today, optimal conditions for initial pre-heating temperatures are only available for specific materials. Thus, in order to extend the EBM technology to other desired build materials, a much better understanding of the pre-heating stages is required. In this work, numerical and experimental approaches are combined in order to investigate the effects and sensitivities of heat removal from the build plate during EBM pre-heating stages. For this purpose, a carefully reconstructed numerical model of the build chamber of an ARCAM Q20 + machine is developed. It includes all main parts of the chamber and all relevant heat transfer mechanisms, whereas special attention is paid to radiation heat exchange between various bodies. In order to validate the model, dedicated experiments are performed, in which a system of thermocouples is installed in the build chamber, allowing direct measurement of the local temperatures of the start-plate and heat shields. A good agreement between the simulation and experimental findings is achieved, leading to a better understanding of the thermal processes characteristic to the pre-heating stages. This basic analysis is followed by a representative pre-heating case, where a powder bed is also considered. The energy required to obtain the desired pre-heating temperatures is evaluated, and the role of the powder bed in heat transfer within the chamber is assessed. The pre-heating stage, simulated in the present work, is supposed to create proper conditions for sintering and consequent melting of the powder, which are highly dependent on the local temperatures and heat transfer features. Thus, the findings of the reported work present a step towards a better understanding of the thermal processes that characterize EBM. The reported model can be further used to provide realistic boundary condition inputs for other meso- or macro-scale models as a function of time and geometry. The model can serve also for verification of machine settings, i.e., jump-safe and melt-safe ones which actually provide desired preheat, and for development of settings for new powders.

36 MATERIALS SCIENCE↗
NASA NTRS1997

Thermal Characterization of Defects in Aircraft Structures Via Spatially Controlled Heat Application

Recent advances in thermal imaging technology have spawned a number of new thermal NDE techniques that provide quantitative information about flaws in aircraft structures. Thermography has a number of advantages as an inspection technique. It is a totally noncontacting, nondestructive, imaging technology capable of inspecting a large area in a matter of a few seconds. The development of fast, inexpensive image processors have aided in the attractiveness of thermography as an NDE technique. These image processors have increased the signal to noise ratio of thermography and facilitated significant advances in post-processing. The resulting digital images enable archival records for comparison with later inspections thus providing a means of monitoring the evolution of damage in a particular structure. The National Aeronautics and Space Administration's Langley Research Center has developed a thermal NDE technique designed to image a number of potential flaws in aircraft structures. The technique involves injecting a small, spatially controlled heat flux into the outer surface of an aircraft. Images of fatigue cracking, bond integrity and material loss due to corrosion are generated from measurements of the induced surface temperature variations. This paper will present a discussion of the development of the thermal imaging system as well as the techniques used to analyze the resulting thermal images. Spatial tailoring of the heat coupled with the analysis techniques represent a significant improvement in the delectability of flaws over conventional thermal imaging. Results of laboratory experiments on fabricated crack, disbond and material loss samples will be presented to demonstrate the capabilities of the technique. An integral part of the development of this technology is the use of analytic and computational modeling. The experimental results will be compared with these models to demonstrate the utility of such an approach.

Cramer, K. Elliott↗