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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
NASA NTRS2004

High Speed, High Temperature, Fault Tolerant Operation of a Combination Magnetic-Hydrostatic Bearing Rotor Support System for Turbomachinery

Closed loop operation of a single, high temperature magnetic radial bearing to 30,000 RPM (2.25 million DN) and 540 C (1000 F) is discussed. Also, high temperature, fault tolerant operation for the three axis system is examined. A novel, hydrostatic backup bearing system was employed to attain high speed, high temperature, lubrication free support of the entire rotor system. The hydrostatic bearings were made of a high lubricity material and acted as journal-type backup bearings. New, high temperature displacement sensors were successfully employed to monitor shaft position throughout the entire temperature range and are described in this paper. Control of the system was accomplished through a stand alone, high speed computer controller and it was used to run both the fault-tolerant PID and active vibration control algorithms.

Jansen, Mark↗
DOE OSTI2021

Ultra High Speed High Temperature Motor

The goal of this project was to develop a high-speed, high-temperature motor capable of operating at 650 ºC, 60,000 rpm, and 125 kW with 50 kW/L. Key objectives to achieve this goal were to develop a suitable high-temperature wire, designing and fabricating rotor and stator subassemblies, designing an inverter assembly, and thermomechanical validation of the fully assembled motor. Four candidates for high-temperature wire were evaluated using test solenoid structures and finite element analysis modeling. The best candidate was a silicone-enameled copper wire suitable for continuous operation at 593 ºC. The rotor for the motor was designed to use a composite material comprised of 74% iron and 26% mullite by volume. This material would be suitable for 3D printing of the rotor. At the end of the project a vacuum mixer was under construction to produce the bubble-free material needed to achieve the highest strength composite after 3D printing. Rotor testing at 60,000 rpm would have commenced immediately following the additive manufacturing process. The project abruptly ended when key personnel left the project without notice.

42 ENGINEERING↗
NASA NTRS1972

High speed, high performance /Hg,Cd/Te photodiode detectors.

The current performance of high speed photodiode detectors for the 1 to 10 micron spectral region is discussed. The (Hg,Cd)Te photodiode configuration, detector properties, integration in laser receiver modules, and frequency response are considered for near infrared and far infrared wavelengths. The recent advances in (Hg,Cd)Te material and device development are indicated by the realization not only of exceptionally high speed detectors but of detectors that exhibit excellent detectivities. The performance improves substantially when the detector is cooled. This detector junction technology has been extended to other compositions of (Hg,Cd)Te for peak spectral responses at 5 and 10 micron.

Soderman, D. A.↗
NASA NTRS2013

Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests

high speed imaging↗
NASA NTRS2013

Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests.

composite materials↗
NASA NTRS2013

Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static tests.

Kohlman, Lee↗
DOE OSTI2020

A High-Speed High-Power-Density Non-Heavy Rare-Earth Permanent Magnet Traction Motor

There has been a global push for higher torque density and lower cost traction motors. The use of non-heavy rare-earth (non-HRE) permanent magnet materials in traction motors are being investigated for the sustainability, profitability and affordability of electric vehicles and to broaden their adoption. A 20,000-rpm permanent magnet traction motor using non-HRE magnet materials is proposed. A dual three-phase winding configuration driven by a segmented dual three-phase drive is proposed to reduce the current ripple, and as a result, the DC Link capacitor, as well as to ease the voltage constraint at high speed and eliminate any risk of uncontrolled regeneration. Furthermore, the dual winding configuration enables a fault tolerant design which is useful for reliability. The paper presents comprehensive electromagnetic, thermal and mechanical designs and analyses using an integrated approach. The results have shown that the design is robust against demagnetization and confirmed its thermal and mechanical viability.

47 OTHER INSTRUMENTATION↗
DOE OSTI2016

High speed high dynamic range high accuracy measurement system

A measuring system includes an input that emulates a bandpass filter with no signal reflections. A directional coupler connected to the input passes the filtered input to electrically isolated measuring circuits. Each of the measuring circuits includes an amplifier that amplifies the signal through logarithmic functions. The output of the measuring system is an accurate high dynamic range measurement.

47 OTHER INSTRUMENTATION↗
DOE OSTI2017

High speed, high current pulsed driver circuit

Various technologies presented herein relate to driving a LED such that the LED emits short duration pulses of light. This is accomplished by driving the LED with short duration, high amplitude current pulses. When the LED is driven by short duration, high amplitude current pulses, the LED emits light at a greater amplitude compared to when the LED is driven by continuous wave current.

42 ENGINEERING↗
NASA NTRS1987

Rupture testing for the quality control of electrodeposited copper interconnections in high-speed, high-density circuits

Printed Wiring Multilayer Board (PWMLB) structures for high speed, high density circuits are prone to failure due to the microcracking of electrolytic copper interconnections. The failure can occur in the foil that makes up the inner layer traces or in the plated through holes (PTH) deposit that forms the layer to layer interconnections. It is shown that there are some distinctive differences in the quality of Type E copper and that these differences can be detected before its use in a PWMLB. It is suggested that the strength of some Type E copper can be very low when the material is hot and that it is the use of this poor quality material in a PWMLB that results in PTH and inner layer microcracking. Since the PWMLB failure in question are induced by a thermal stress, and since the poorer grades of Type E materials used in these structures are susceptible to premature failure under thermal stress, the use of elevated temperature rupture and creep rupture testing is proposed as a means for screening copper foil, or its PTH equivalent, in order to eliminate the problem of Type E copper microcracking in advanced PWMLBs.

Zakraysek, Louis↗
NASA NTRS2009

Enhancement of USM3D Unstructured Flow Solver for High-Speed High-Temperature Shear Flows

Large temperature and pressure fluctuations have a profound effect on turbulence development in transonic and supersonic jets. For high-speed, high-temperature jet flows, standard turbulence models lack the ability to predict the observed mixing rate of a shear layer. Several proposals to address this deficiency have been advanced in the literature to modify the turbulence transport equations in a variety of ways. In the present study, some of the most proven and simple modifications to two-equation turbulence models have been selected and implemented in NASA's USM3D tetrahedral Navier-Stokes flow solver. The modifications include the addition of compressibility correction and pressure dilatation terms in the turbulence transport equations for high-speed flows, and the addition of a simple modification to the Boussinesq's closure model coefficient for high-temperature jets. The efficacy of the extended models is demonstrated by comparison with experimental data for two supersonic axisymmetric jet test cases at design pressure ratio.

Pandya, Mohagna J.↗
NASA NTRS2010

Low Speed and High Speed Correlation of SMART Active Flap Rotor Loads

Measured, open loop and closed loop data from the SMART rotor test in the NASA Ames 40- by 80- Foot Wind Tunnel are compared with CAMRAD II calculations. One open loop high-speed case and four closed loop cases are considered. The closed loop cases include three high-speed cases and one low-speed case. Two of these high-speed cases include a 2 deg flap deflection at 5P case and a test maximum-airspeed case. This study follows a recent, open loop correlation effort that used a simple correction factor for the airfoil pitching moment Mach number. Compared to the earlier effort, the current open loop study considers more fundamental corrections based on advancing blade aerodynamic conditions. The airfoil tables themselves have been studied. Selected modifications to the HH-06 section flap airfoil pitching moment table are implemented. For the closed loop condition, the effect of the flap actuator is modeled by increased flap hinge stiffness. Overall, the open loop correlation is reasonable, thus confirming the basic correctness of the current semi-empirical modifications; the closed loop correlation is also reasonable considering that the current flap model is a first generation model. Detailed correlation results are given in the paper.

Kottapalli, Sesi B. R.↗
DOE OSTI2018

Transient dynamics of powder spattering in laser powder bed fusion additive manufacturing process revealed by in-situ high-speed high-energy x-ray imaging

Powder spattering is a major cause of defect formation and quality uncertainty in the laser powder bed fusion (LPBF) additive manufacturing (AM) process. It is very difficult to investigate this with either conventional characterization tools or modeling and simulation. The detailed dynamics of powder spattering in the LPBF are still not fully understood. Here, we report insights into the transient dynamics of powder spattering in the LPBF process that were observed with in-situ high-speed high-energy x-ray imaging. Powder motion dynamics, as functions of time, environment pressure, and location, are presented. The moving speed, acceleration, and driving force of powder motion that are induced by metal vapor jet/plume and argon gas flow are quantified. A schematic map showing the dynamics and mechanisms of powder motion during the LPBF process as functions of time and pressure is constructed. In conclusion, potential ways to mitigate powder spattering during the LPBF process are discussed and proposed, based on the revealed powder motion dynamics and mechanisms.

36 MATERIALS SCIENCE↗
NASA NTRS2013

High-Speed, High-Resolution Time-to-Digital Conversion

This innovation is a series of time-tag pulses from a photomultiplier tube, featuring short time interval between pulses (e.g., 2.5 ns). Using the previous art, dead time between pulses is too long, or too much hardware is required, including a very-high-speed demultiplexer. A faster method is needed. The goal of this work is to provide circuits to time-tag pulses that arrive at a high rate using the hardwired logic in an FPGA - specifically the carry chain - to create what is (in effect) an analog delay line. High-speed pulses travel down the chain in a "wave." For instance, a pulse train has been demonstrated from a 1- GHz source reliably traveling down the carry chain. The size of the carry chain is over 10 ns in the time domain. Thus, multiple pulses will travel down the carry chain in a wave simultaneously. A register clocked by a low-skew clock takes a "snapshot" of the wave. Relatively simple logic can extract the pulses from the snapshot picture by detecting the transitions between logic states. The propagation delay of CMOS (complementary metal oxide semiconductor) logic circuits will differ and/or change as a result of temperature, voltage, age, radiation, and manufacturing variances. The time-to-digital conversion circuits can be calibrated with test signals, or the changes can be nulled by a separate on-die calibration channel, in a closed loop circuit.

Katz, Richard↗