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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Relationship of Chemical Composition and Moisture Sensitivity in LiNi x Mn y Co 1-x-y O 2 for Lithium-Ion Batteries

Chemical composition–moisture sensitivity relationship of LiNi x Mn y Co 1-x-y O 2 (NMC) cathode materials was investigated by exploring crystal structures, surface properties, and electrochemical performance behaviors of various commercial NMC powders: LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NMC111), LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532), LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622), and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811). The NMC powders were stored in different moisture conditions: moisture-free, humidified air, or immersed in water. Rietveld refinement analysis of X-ray diffraction (XRD) data and scanning electron microscopy (SEM) were used to characterize the crystal structure changes and the evolution of particle surfaces morphologies. The effect of moisture contamination on the electrochemical properties of NMC cathodes was studied by galvanostatic cycling and electrochemical impedance spectroscopy (EIS). The moisture contamination resulted in either structural disorder or unwanted surficial deposition products, which increased a charge-transfer impedance and consequent performance degradation of battery cells. The results showed that NMC’s moisture vulnerability increased with Ni content (x) despite protective coatings on commercial particles, which stressed the necessity of alternative surface passivation strategies of Ni-rich NMC for broad applications such as electric vehicles and electrified aircraft propulsion.

25 ENERGY STORAGE↗
DOE OSTI2022

WBG-Enabled Current-Source Inverters for Integrated PM Motor Drives

This project takes advantage of the special capabilities of wide-bandgap (WBG) power semiconductor devices to develop innovative power electronics in the form of new current-source inverters (CSIs) that offer promising advantages over the dominant voltage-source inverter (VSI) topology. These CSIs, in turn, are extremely well-suited for integration into the housings of permanent magnet synchronous machines (PMSMs) to form integrated motor drives (IMDs). These new IMDs offer great promise for achieving major energy savings in a wide variety of applications that benefit from adjustable-speed control, including air conditioners, laundry appliances, industrial pumps/compressors, electric vehicles, and aerospace drives. WBG devices play a critical enabling role in these new IMDs because of their transformative features including much higher switching frequencies, lower losses, and compatibility with high operating temperatures. When incorporated into new CSI-based IMDs with PM machines, these WBG switches open the door to achieving major increases in power density, drive system efficiency, and fault tolerance, as well as substantial reductions in electromagnetic interference (EMI), manufacturing cost, and temperature-induced failures. The higher operating temperature capability of WBG devices compared to conventional silicon power devices is very appealing in IMD applications because the power electronics is mounted in close proximity to the motors which typically operate at temperatures well above the maximum limits of today’s silicon-based power electronics. This project has succeeded in designing, building, and testing multiple prototype versions of this CSI-IMD that have overcome many technical challenges in order to demonstrate the impressive performance improvements that can be achieved by the WBG-enabled CSI-IMD. The preliminary demo and bench-top versions of the current-source inverter developed during the first two years of the project were critical to laying the technical foundations for the 3 kW prototype CSI-IMD unit that was successfully built and tested during the third year. This prototype CSI-IMD unit was designed to fit within the housing envelope of the original permanent magnet (PM) synchronous machine in order to meet the demanding power density requirements that were set at the beginning of the project. All of the remaining performance objectives set for the prototype CSI-IMD unit including efficiency and electromagnetic interference (EMI) were also met. The last 18 months of the project were devoted to developing further enhancements of the WBG-enabled CSI-IMD technology that better prepare it for commercial production. More specifically, an upgraded version of the prototype CSI-IMD unit was developed that moved the power electronics into the same machine housing chamber as the motor, substantially raising the thermal demands on the power electronics. Tests with five different combinations of motor enclosure types and air cooling configurations were evaluated. Importantly, this work confirmed that the power electronics can deliver its full rated power and still operate well within its maximum temperature limits even for worst-case conditions when the housing is “totally-enclosed” without any openings for air to enter or exit the enclosure, and no blower/fan is provided to blow air over the outside surface of the enclosure. Reaching the full performance and energy-savings potential of this disruptive CSI-IMD motor drive technology is highly consistent with ARPA-E’s stated mission to “enhance the economic and energy security of the United States” while also supporting its commitment to “ensure that the U.S. maintains a technological lead in developing and deploying advanced energy technologies”. Follow-on projects are under way to explore the scalability of WBG-enabled CSI-IMD technology to 100 kW (peak) electric vehicle traction drives and fault-tolerant modular motor drives for future electrified aircraft propulsion applications.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS2018

NASA Emissions Research Overview

NASA Aeronautics is advancing a variety of technologies toward the objective of reducing aviation fuel burn and emissions. Specifically, the Advanced Air Transport Technology Project under the Advanced Air Vehicles Program is investing in technologies such as small core engines, fuel-flexible combustors, and electrified aircraft propulsion, all of which offer potential for reduced fleet fuel usage and harmful emissions. This presentation will provide a brief overview of these technical approaches as well as a NASA Aeronautics budget outlook.

Heidmann, Jim↗
NASA NTRS2018

Turbo-Generation Control

Electrified Aircraft Propulsion (EAP) power systems are being studied at the NASA Electric Aircraft Testbed (NEAT) facility. The electric motors at NEAT have the capability to dynamically respond to commands that would be unrealistic when integrated with turbomachinery. There is a need to provide more realistic turbine transients for future system performance studies.

Hybrid Electric↗
NASA NTRS2018

Electric Aircraft Technology Development Overview Briefing

This is a presentation to the NAC Aeronautics Committee providing an overview of electrified aircraft propulsion technology development for the following targeted vehicle classes 1) Single-Aisle Transports, 2) Vertical Takeoff and Landing-Urban Air Mobility, and 3) Thin Haul Conventional Takeoff and Landing as well as enabling test capabilities.

Esker, Barbara↗
NASA NTRS2019

High Efficiency Megawatt Motor Preliminary Design

The High Efficiency Megawatt Motor (HEMM) is being designed to meet the needs of Electrified Aircraft Propulsion (EAP). A preliminary design has been completed and risk reduction activities are being conducted in three key areas: cryogenic cooler design, superconducting rotor coil design and manufacturing, and stator thermal management. The key objective of HEMM is to establish a motor technology which simultaneously attains high specific power (>16kW/kg ratio to electromagnetic weight) and high efficiency (>98%) by judicious application of high temperature superconducting wire and integrated thermal management. Another important feature is to achieve the performance goals with an eye to aircraft integration constraints. An electromagnetic analysis was performed which shows that the proposed HEMM design meets the performance objectives if key current capability and mechanical constraints are achieved. The risk reduction activities are the first assessment of the key design features. The HEMM technology could be applied to a range of aircraft types that require megawatt level electrical power.

Jansen, Ralph H.↗
NASA NTRS2018

High Efficiency Megawatt Motor Conceptual Design

The High Efficiency Megawatt Motor (HEMM) is being designed to meet the needs of Electrified Aircraft Propulsion (EAP). The key objective of this work is to establish a motor technology which simultaneously attains high specific power (>16kW/kg ratio to electromagnetic weight) and high efficiency (>98%) by judicious application of high temperature superconducting wire and integrated thermal management. Another important feature is to achieve the performance goals with an eye to aircraft integration constraints. An electromagnetic analysis was performed which shows that the proposed HEMM design meets the performance objectives if key current capability and mechanical constraints are achieved. Sensitivity of motor power and performance to those parameters is illustrated. The HEMM technology could be applied to a range of aircraft types that require megawatt level electrical power.

Jansen, Ralph H.↗
NASA NTRS2020

Core Losses in Co-Rich Inductors with Tunable Permeability

High frequency, low loss power systems enable electrified aircraft propulsion. Filter inductors that reduce noise in high current systems can account for 50% of the motor drive mass. Efficient inductor cores with tunable permeability reduce system mass by producing less heat, that removes heat sink mass. Requirements for filter inductors vary based on the chosen topology, but all inductor cores must operate below saturation levels. As the saturation flux density is limited (less than ~2 T), high differential current applications require cores with low relative permeabilities. The large induced anisotropies possible in Co-rich metal amorphous nanocomposite materials enables gapless inductors with relative permeabilities down to ~20. These materials have fine grain size ~8nm with a faulted, close packed structure. The impact of different processing methods on core losses are presented along with comparison to other low permeability soft magnetic materials.

Leary, Alex↗
NASA NTRSDate not supplied

A Study of Large Scale Power Extraction and Insertion on Turbofan Performance and Stability

This paper describes the effects of turbofan power extraction and insertion (augmentation) on engine performance and stability. The purpose of this paper is to present how power augmentation affects a dual spool gas turbine engine cycle where the engine will also be required to provide thrust. The goals for the paper are to describe effective limits of power augmentation and offer strategies, utilizing spool choice and variable geometries, to maximize augmentation effect. While Analysis is general two potential uses are explored: Power extraction for electrified aircraft propulsion purposes. And, Power insertion for thrust assist. Results of the paper show it is possible to extract over 20% (at 85% max thrust) and gain roughly 12% of maximum thrust through power insertion.

Gas Turbine Engines↗
NASA NTRSDate not supplied

A Study of Large Scale Power Extraction and Insertion on Turbofan Performance and Stability

This describes the effects of turbofan power extraction and insertion (augmentation) on engine performance and stability. The purpose of this paper is to present how power augmentation affects a dual spool gas turbine engine cycle where the engine will also be required to provide thrust. The goals for the paper are to describe effective limits of power augmentation and offer strategies, utilizing spool choice and variable geometries, to maximize augmentation effect. While Analysis is general, two potential uses are explored: Power extraction for electrified aircraft propulsion and power insertion for thrust assist. Results of the paper show it is possible to extract over 20% (at 85% max thrust) and gain roughly 12% of maximum thrust through power insertion.

Gas Turbine engines↗
NASA NTRS2020

Electrical Modeling and Thermal Analysis Toolbox (EMTAT) User’s Guide

A simulation toolbox has been developed to model the electrical portions of Electrified Aircraft Propulsion (EAP) systems, including self-heating of electrical systems. Dynamic models of EAP systems often include turbomachinery, an electrical power system, and a thermal management system. These portions of the propulsion system can operate on timescales covering six orders of magnitude, which poses a challenging modeling task. Assumptions and approximations are made in an effort to capture the dynamics relevant to engine, electrical system, and thermal system interactions, while still allowing for fast simulations. These assumptions and approximations enable the electrical component models to run at the time scale of the turbomachinery, neglecting the very high frequency electrical dynamics, while demonstrating representative behavior of the end-to-end system. Thus the models execute in an acceptable time frame for what would otherwise be an extremely stiff simulation. The resulting simulations of EAP systems are appropriate for system-level control design and analysis. The objective of this User's Guide is to present an overview of the usage of the Electrical Modeling and Thermal Analysis Toolbox (EMTAT). It will describe some of the approximations made to accommodate rapid execution, and some of the design tools that allow matching the model to component specifications. This paper will describe the basic usage of the software toolbox, and also provide an example of EAP system modeling using EMTAT.

Mark E. Bell↗
NASA NTRS2021

A Study of Large-Scale Power Extraction and Insertion on Turbofan Performance and Stability

This paper describes the effects of turbofan power extraction and insertion (augmentation) on engine performance and stability. The purpose of this paper is to present how power augmentation affects a dual spool gas turbine engine cycle where the engine will also be required to provide thrust. The goals for the paper are to describe effective limits of power augmentation and offer strategies, utilizing spool choice and variable geometries, to maximize augmentation effect. While Analysis is general, two potential uses are explored: Power extraction for electrified aircraft propulsion and power insertion for thrust assist. Results of the paper show it is possible to extract over 20% (at 85% max thrust) and gain roughly 12% of maximum thrust through power insertion.

Gas Turbine engines↗
NASA NTRSDate not supplied

Thermal Management System Trade Study for SUSAN Electrofan Aircraft

Thermal management of power system components is one of the barriers identified towards the implementation of Electrified Aircraft Propulsion architectures. This paper documents the preliminary results of a trade space exploration of thermal management systems conducted for a new National Aeronautics and Space Administration regional transport aircraft concept called the SUbsonic Single Aft eNgine (SUSAN) Electrofan. Traditional methods of thermal management are evaluated alongside newer methods, which are still in development. Mass, power, and drag for traditional liquid / air heat exchangers were calculated, along with mass and area of oscillating heat pipes for outer mold line cooling. An initial assessment of the feasibility of using the fuel as part of the thermal management system was also conducted by evaluating the temperature over the full flight profile. Preliminary results and future work are discussed.

Nic Heersema↗
NASA NTRSDate not supplied

A Design Exploration of Natural Laminar Flow Applications for the SUSAN Electrofan Concept

A trade study supported by the NASA Convergent Aeronautics Solutions (CAS) Project is presently underway to explore the desirability, feasibility, and viability of a new vehicle concept. The vehicle under development is the SUbsonic Single Aft eNgine (SUSAN) Electrofan configuration, which is a subsonic regional jet with the transformative concept of combining wing-mounted distributed electrified aircraft propulsion with a single engine design. The multidisciplinary team is investigating several potential technologies that would help the SUSAN Electrofan configuration achieve its performance goals, one of which is the application of Natural Laminar Flow (NLF) to the main wing. The present computational study utilizes the Crossflow Attenuated Natural Laminar Flow (CATNLF) design method to reshape the wing airfoils to obtain significant extents of NLF at the cruise condition. Fully-turbulent and laminar designs were performed to quantify the aerodynamic performance potential of NLF on the SUSAN Electrofan configuration. The laminar design supported laminar flow on53% of the area of the wing upper surface, resulting in a 19count (8.8%) drag reduction for the wing-fuselage configuration. The near-cruise off-design characteristics are also studied and illustrate that the robust laminar design sustains an NLF performance benefit through perturbations in Mach and angle of attack. A discussion is also included on multidisciplinary implications of utilizing NLF for the configuration, including design, manufacturing, and operational considerations required to support NLF on the main wing, as well as the interaction between the potential wing-mounted boundary layer ingestion technology that is also being explored for the SUSAN Electrofan configuration.

Natural Laminar Flow↗
NASA NTRSDate not supplied

Dynamic Bellows for a Pulse Tube Cryocooler Application

Electrified aircraft propulsion systems will require powertrain components that are both lightweight and highly efficient. NASA’s 1.4 MW High Efficiency Megawatt Motor (HEMM) has been designed to run at 6800 RPM with >98% efficiency and 16 kW/kg, achieving low losses by incorporating a cryocooler within its rotor shaft to cool superconducting DC windings. A pulse-tube cryocooler typically contains an oscillating piston that drives acoustic waves; however, leakage around the piston reduces the efficiency of the cryocooler. A metal bellows was designed to replace the piston to allow for little to no leakage. The requirements for this bellows were extreme in terms of displacement amplitude, oscillating pressure amplitude, temperature, and frequency. It was determined that an off-the-shelf edge-welded bellows would not work for this application, so a custom bellows was designed to include full convolutions welded only on their outer diameters where the stress is lower. Several high-fatigue-strength materials were considered, including 17-4PH H900 and Aermet 100. The final bellows design includes 74 convolutions with a variable inner diameter that helps distribute and reduce the dynamic stress throughout the length rather than concentrating the high stress in one location. To test the concept, a short 10-convolution bellows with constant inner diameter was designed for testing. One short bellows test article was fabricated with the outer diameter weld, and one by 3D printing. Both will be fatigue-tested with the goal of achieving 10^7 cycles.

Bellows↗
NASA NTRSDate not supplied

Initial Regulatory and Certification Approach for the SUSAN Electrofan Concept

New aircraft concepts and associated technologies are required to meet emerging environ-mental impact goals, while still meeting established airworthiness certification standards and regulations. The SUbsonic Single Aft eNgine (SUSAN) Electrofan is one of these concepts, utilizing a single aft-mounted engine, electrified aircraft propulsion, and an emergency backup battery. This paper explores the current certification and regulatory barriers to this novel aircraft design and the potential methods for adapting certification and regulatory requirements for the SUSAN Electrofan concept. Although some certification requirements, such as the Extended Operations regulations for continued operation after the loss of an engine, can be met with only minor changes, other requirements require modifications to the regulations or the aircraft concept for compliance. Early insight to the certification approach for the SUSAN concept, while the design is still undergoing trade space exploration, allows the development of the aircraft alongside any modifications to certification standards.

SUSAN Electrofan↗
NASA NTRSDate not supplied

Electrical System Trade Study for SUSAN Electrofan Concept Vehicle

The SUSAN Electrofan Aircraft concept is a subsonic regional jet transport aircraft that utilizes a single turbofan engine and Electrified Aircraft Propulsion (EAP) to enable propulsive and aerodynamic benefits to reduce fuel usage, emissions, and cost. This paper is a trade space exploration of the electrical system for the concept aircraft, including possible system architectures, and a review of the specific powers and efficiencies required for the electrical components to realize the EAP system.

Joseph M Haglage↗