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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Bearingless Flywheel Systems, Winding and Control Schemes, and Sensorless Control

Flywheel systems are disclosed that provide increased energy density and operational effectiveness. A first bearingless motor and a second bearingless motor may be configured to simultaneously suspend the central rotor in a radial direction and to rotate the central rotor. However, certain implementations may have one motor or more than two motors, depending on the design. A plurality of the flywheel systems may be collectively controlled to perform community energy storage with higher storage capacities than individual flywheel systems.

Jansen, Ralph H↗
NASA NTRS2018

Testing and Maturing a Mass Translating Mechanism for a Deep Space CubeSat

Near Earth Asteroid (NEA) Scout is a deep space satellite set to launch aboard NASA's Exploration Mission 1. The spacecraft fits within a CubeSat standard 6U (about 300 x 200 x 100 mm) and is designed to travel 1 AU over a 2.5 year mission to observe NEA VG 1991. The spacecraft will use an 86 sq.m solar sail to maneuver from lunar orbit to the NEA. One of the critical mechanisms aboard NEA Scout, the Active Mass Translator (AMT), has gone through rigorous design and test cycles since its conception in July of 2015. The AMT is a two-axis translation table required to balance the spacecraft's center of mass (CM) and solar sail center of pressure (CP) while also trimming disturbance torque created by off-nominal sail conditions. The AMT has very limited mass and volume requirements, but is still required to deliver a large translation range-about 160 x 68 mm-at sub mm accuracy and precision. The system is constrained to operate in complete exposure to space with limited power and data budgets for mechanical and thermal needs. The NEA Scout team developed and carried out a rigorous test suite for the prototype and engineering development unit (EDU). These tests uncovered numerous design failures and led to many failure investigations and iteration cycles. A paper was previously presented at the 43rd Aerospace Mechanisms Symposia entitled, "Development of a High Performance, Low Profile Translation Table with Wire Feedthrough for a Deep Space CubeSat". This paper will make note of specific lessons learned: manufacturing philosophy, testing ideologies for high-risk missions, thermal mitigation design for small, motor-driven mechanisms.

Few, Alex↗
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

Design Study of a Coupled Inner-Stator Magnetically Geared Motor for Electric Aircraft Applications

Electric aircraft require high performance and high reliability electric motor drivetrains. A geared electric motor drivetrain will outperform a direct drive motor drivetrain in most applications. Traditional mechanical gearing, however, has mechanical contact-based wear and failure modes that result in added maintenance costs and require an oil lubrication system. Magnetically geared motor drives are a potential technology for electric aircraft applications capable of enabling the benefits of a geared drive without the maintenance, reliability, and lubrication system cost of mechanical gears. In this paper, a topology of magnetically geared motor, an inner stator magnetically geared motor, is explored to estimate its achievable performance for electric aircraft applications. Optimization results on the topology show that it can achieve greater than 15 Nm/kg and 96% efficiency at 100 kW of power.

Thomas Tallerico↗
NASA NTRSDate not supplied

Design Study of a Coupled Inner-Stator Magnetically Geared Motor for Electric Aircraft Applications

Abstract- Electric aircraft require high performance and high reliability electric motor drivetrains. A geared electric motor drivetrain will outperform a direct drive motor drivetrain in most applications. Traditional mechanical gearing, however, has mechanical contact-based wear and failure modes that result in added maintenance costs and require an oil lubrication system. Magnetically geared motor drives are a potential technology for electric aircraft applications capable of enabling the benefits of a geared drive without the maintenance, reliability, and lubrication system cost of mechanical gears. In this paper, a topology of magnetically geared motor, an inner-stator magnetically geared motor, is explored to estimate its achievable performance for electric aircraft applications. Optimization results on the topology show that it can achieve greater than 15 Nm/kg specific torque and 96% efficiency at 100 kW of power.

Thomas Tallerico↗
DOE OSTI2022

Design and Verification of An Open-Circuit Electro-Hydraulic Actuator System with An Integrated Electro-Hydraulic Unit

This paper proposes an electro-hydraulic actuator (EHA) system, and two novel-designed electro-hydraulic units (EHU) consisting of a fixed-displacement hydraulic pump and a variable-speed electric motor. Both the novel EHU designs integrate an electric machine and a hydraulic machine in a single unit, featuring compactness and power density. However, they differ for salient aspects such as power and electric machine cooling system. The EHA system features an open circuit design, where hydraulic hoses connect the EHU with a tank, a valve manifold, and the hydraulic cylinder. In this way, the proposed EHA technology can be used to implement distributed hydraulic actuation in a vehicle without requiring changes to the hydraulic actuators or at the overall layout of the hydraulic components with respect to the original vehicle design. A dedicated test rig is developed to verify the performance of the proposed EHA system. The efficiency of the EHA is measured in a steady state and under a realistic duty cycle of a commercial compact loader. The measured efficiency of the system can reach 54% with up to 20kN load and 6kW power level.

42 ENGINEERING↗
NASA NTRS1978

Design, analysis, fabrication and test of the Space Shuttle solid rocket booster motor case

The motor case used in the solid propellant booster for the Space Shuttle is unique in many respects, most of which are indigenous to size and special design requirements. The evolution of the case design from initial requirements to finished product is discussed, with increased emphasis of reuse capability, special design features, fracture mechanics and corrosion control. Case fabrication history and the resulting procedure are briefly reviewed with respect to material development, processing techniques and special problem areas. Case assembly, behavior and performance during the DM-1 static firing are reviewed, with appropriate comments and conclusions.

Kapp, J. R.↗
NASA NTRS1995

Plume particle collection and sizing from static firing of solid rocket motors

A unique dart system has been designed and built at the NASA Marshall Space Flight Center to collect aluminum oxide plume particles from the plumes of large scale solid rocket motors, such as the space shuttle RSRM. The capability of this system to collect clean samples from both the vertically fired MNASA (18.3% scaled version of the RSRM) motors and the horizontally fired RSRM motor has been demonstrated. The particle mass averaged diameters, d43, measured from the samples for the different motors, ranged from 8 to 11 mu m and were independent of the dart collection surface and the motor burn time. The measured results agreed well with those calculated using the industry standard Hermsen's correlation within the standard deviation of the correlation . For each of the samples analyzed from both MNASA and RSRM motors, the distribution of the cumulative mass fraction of the plume oxide particles as a function of the particle diameter was best described by a monomodal log-normal distribution with a standard deviation of 0.13 - 0.15. This distribution agreed well with the theoretical prediction by Salita using the OD3P code for the RSRM motor at the nozzle exit plane.

Sambamurthi, Jay K.↗
NASA NTRS1993

Advanced Solid Rocket Motor nozzle development status

This paper presents a status update of the design and development of an improved nozzle for the Advanced Solid Rocket Motor (ASRM). The ASRM nozzle incorporates advanced state-of-the-art design features and materials which contribute to enhanced safety, reliability, performance, and producibility for the space shuttle boosters. During 1992 the nozzle design progressed through a successful Preliminary Design Review (PDR). An improved ablative material development program also culminated in the selection of new standard and low density carbon cloth phenolic prepreg offering reduced variability and improved process attributes. A subscale motor test series to evaluate new materials and design features was also completed. An overview update of the matured design characteristics, supporting analysis, key development-program results and program status and plans is reported.

Kearney, W. J.↗
NASA NTRS1983

Positional repeatability measurements of stepper motors at cryogenic temperatures

For cryogenically-cooled infrared instruments and telescopes employed in space, reliable and predictable motor operations at 4 K in vacuum are in most cases necessary. For the Shuttle Infrared Telescope Facility (SIRTF), stepper motors may be employed in a number of applications. A test facility was designed and built for measuring stepper motor positional repeatability, in vacuum, over a temperature range from ambient to liquid helium temperature. Tests regarding positional repeatability were conducted at different motor speeds, directions of motor rotation, step sizes, and power conditions. In addition, tests were performed with respect to the ability of the motor to remain in a position with no power applied to the motor.

Pompea, S. M.↗
DOE OSTI2026

Propulsion System Design using a Dual 3-Phase PM Synchronous Reluctance Machine with X-Type Multi-Level GaN Inverter

— A propulsion system design is exhibited here that comprises of an X-type GaN power module based dual multi-level inverter and a PM Synchronous Reluctance motor. With the critical benefits of multi-level operation, namely low common mode EMI noise, low switching loss, low current Total Harmonic Distortion (THD), smoother torque and lower iron loss, this topology targets high system-level efficiency and high power density while using reduced rare earth (RE) elements in its motor. General Motors and Purdue University jointly designed and developed this 800V class, highly scalable traction drive that can deliver 200+ kW of power suitable for C-SUV to truck vehicle class. The 3-phase electric machine design utilizes dual winding with 6 terminals to work in line with the GaN X-type inverter, and results in a tractive solution that ensures higher machine efficiency while reducing cost and uncertainty related to use and availability of heavy rare earth/rare earth elements in its rotor.

MOMEN, FAIZUL [General Motors LLC, Detroit, MI (Un↗
NASA NTRS1995

Advanced control design for hybrid turboelectric vehicle

The new environment standards are a challenge and opportunity for industry and government who manufacture and operate urban mass transient vehicles. A research investigation to provide control scheme for efficient power management of the vehicle is in progress. Different design requirements using functional analysis and trade studies of alternate power sources and controls have been performed. The design issues include portability, weight and emission/fuel efficiency of induction motor, permanent magnet and battery. A strategic design scheme to manage power requirements using advanced control systems is presented. It exploits fuzzy logic, technology and rule based decision support scheme. The benefits of our study will enhance the economic and technical feasibility of technological needs to provide low emission/fuel efficient urban mass transit bus. The design team includes undergraduate researchers in our department. Sample results using NASA HTEV simulation tool are presented.

Abban, Joseph↗
NASA NTRS1978

Molded composite pyrogen igniter for rocket motors

A lightweight pyrogen igniter assembly including an elongated molded plastic tube adapted to contain a pyrogen charge was designed for insertion into a rocket motor casing for ignition of the rocket motor charge. A molded plastic closure cap provided for the elongated tube includes an ignition charge for igniting the pyrogen charge and an electrically actuated ignition squib for igniting the ignition charge. The ignition charge is contained within a portion of the closure cap, and it is retained therein by a noncorrosive ignition pellet retainer or screen which is adapted to rest on a shoulder of the elongated tube when the closure cap and tube are assembled together. A circumferentially disposed metal ring is provided along the external circumference of the closure cap and is molded or captured within the plastic cap in the molding process to provide, along with O-ring seals, a leakproof rotary joint.

Heier, W. C.↗
NASA NTRS1999

An Instrument for Real-Time Measurement of Solid Rocket Motor Insulation Erosion

An instrument (eroding potentionmeter) has been designed to measure real-time case wall and inhibitor insulation char depth within a rocket motor during firing. Thus measurement can be close to the real-time recession of the insulation surface. The eroding potentionmeter consists of two small (3 mils 9in diameter) twisted resistive wires that are polyimide insulated. The wire pair form an electrical circuit and will recede with the erosion of the rocket motor internal insulation. A constant current applied along the wires will detect the resistance change via a voltage drop across the wires as the wire pair recedes with the decomposition fo the insulation. The eroding potentionmeter, as presently designed, can be an effective tool for real time measurement of internal insulation recession of a solid rocket motor. This tool will provide a way to accurately measure inhibitor performance or to measure flight effects of insulation erosion on a flight test. The eroding potentiometer has been verified on a plasma torch test and two static tests of a small solid rocket motor. There are some irregularities in the measured date, but the data remains useful in determining the real-time performance of internal insulation during a motor firing.

McWhorter, B. B.↗
NASA NTRS1992

Advanced electric motor technology: Flux mapping

This report contains the assumptions, mathematical models, design methodology, and design points involved with the design of an electromechanical actuator (EMA) suitable for directing the thrust vector of a large MSFC/NASA launch vehicle. Specifically the design of such an actuator for use on the upcoming liquid fueled National Launch System (NLS) is considered culminating in a point design of both the servo system and the electric motor needed. A major thrust of the work is in selecting spur gear and roller screw reduction ratios to achieve simultaneously wide bandwidth, maximum power transfer, and disturbance rejection while meeting specified horsepower requirements at a given stroking speed as well as a specified maximum stall force. An innovative feedback signal is utilized in meeting these diverse objectives.

Doane, George B., III↗
NASA NTRS2024

Wheel Module Motor Trade Study for Lunar Terrain Vehicle Thermal Control System

Conducting a lunar mission, whether it is a robotic mission or one with astronauts, has many challenges; one of which is the thermal control of the motors of the wheel module that are used to propel and steer the vehicle. This paper describes the thermal analysis approach, design assumptions, and results of passive thermally controlled wheel module motors, meaning there are not cold plates, fluid loops, or other active thermal control methods to controlling the temperatures. It will also highlight challenges faced in the design of wheel modules for a rover on the lunar south pole. There are three main design change approaches that are considered, the first one keeps the nominal design with the motors mounted at the wheel hub on each wheel, but the motors have lower temperature limits. The second approach requires no thermal control of the motors, allowing them to get below the manufacturers lowest thermal limit and warming them back up prior to actuation during the lunar day. The last approach moves the motors inside of the main body of the vehicle.

Thermal Control System↗
NASA NTRS2020

Efficient Thermal Management for Sampling Arm Actuators

An electric actuator incorporating novel features for thermal management is designed and analyzed. Reducing intra-actuator thermal resistance is not only beneficial for cold missions (helping to pre-heat the gearbox) but can also enable high power applications in benign environments. The proposed design increases the thermal conductance between the motor windings and the motor casing by at least two orders of magnitude over the state of practice actuator designs. The design leverages Additive Manufacturing (AM) to integrate a complex 3 dimensional Oscillating Heat Pipe (OHP) directly within the actuator structure. A baseline actuator without this thermal management feature was fabricated. Testing was conducted to evaluate the temperature difference between actuator components at a range of motor winding heat dissipations. An analysis of a proposed revised design incorporating OHPs into the input structure indicated an increase in the effective thermal conductivity of 8 and 22 times for the nominal and start-up modes respectively. In addition, the thermal conductance between the windings and the input structure is increased by a factor of 90, and the thermal conductance between the windings and the gear assembly is increased by a factor of 200 with the proposed design.

Odagiri, Kimihide↗
NASA NTRS2018

Preliminary Design of the Superconducting Rotor for NASA's High-Efficiency Megawatt Motor

NASA Glenn Research Center is developing a 1.4~MW high-efficiency electric machine for future electrified aircraft to reduce energy consumption, emissions, and noise. This wound-field, synchronous machine employs a self-cooled, superconducting rotor to achieve excellent specific power and efficiency. The design of the superconducting rotor and the optimization of its electromagnetic and structural responses are analyzed in this paper. Candidate designs are evaluated in terms of absolute performance, specific performance, and performance per cost. It is found that optimizing the electromagnetic response for absolute or specific performance yields designs that are similar to each other, but opposite of the cost-optimized design. A method to define the thermal requirements of the superconducting coils and integrated cryocooler is also presented.

electric machines↗