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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2015

ERL with non-scaling fixed field alternating gradient lattice for eRHIC

The proposed eRHIC electron-hadron collider uses a "non-scaling FFAG" (NS-FFAG) lattice to recirculate 16 turns of different energy through just two beam lines located in the RHIC tunnel. This paper presents lattices for these two FFAGs that are optimized for low magnet field and to minimize total synchrotron radiation across the energy range. The higher number of recirculations in the FFAG allows a shorter linac (1.322GeV) to be used, drastically reducing cost, while still achieving a 21.2 GeV maximum energy to collide with one of the existing RHIC hadron rings at up to 250GeV. eRHIC uses many cost-saving measures in addition to the FFAG: the linac operates in energy recovery mode, so the beams also decelerate via the same FFAG loops and energy is recovered from the interacted beam. All magnets will be constructed from NdFeB permanent magnet material, meaning chillers and large magnet power supplies are not needed. This paper also describes a small prototype ERL-FFAG accelerator that will test all of these technologies in combination to reduce technical risk for eRHIC.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Separated-orbit bisected energy-recovered linear accelerator

A separated-orbit bisected energy-recovered linear accelerator apparatus and method. The accelerator includes a first linac, a second linac, and a plurality of arcs of differing path lengths, including a plurality of up arcs, a plurality of downgoing arcs, and a full energy arc providing a path independent of the up arcs and downgoing arcs. The up arcs have a path length that is substantially a multiple of the RF wavelength and the full energy arc includes a path length that is substantially an odd half-integer multiple of the RF wavelength. Operation of the accelerator includes accelerating the beam utilizing the linacs and up arcs until the beam is at full energy, at full energy executing a full recirculation to the second linac using a path length that is substantially an odd half-integer of the RF wavelength, and then decelerating the beam using the linacs and downgoing arcs.

43 PARTICLE ACCELERATORS↗
DOE OSTI2015

Gas turbine engine with supersonic compressor

A gas turbine engine having a compressor section using blades on a rotor to deliver a gas at supersonic conditions to a stator. The stator includes one or more of aerodynamic ducts that have converging and diverging portions for deceleration of the gas to subsonic conditions and to deliver a high pressure gas to combustors. The aerodynamic ducts include structures for changing the effective contraction ratio to enable starting even when designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of two to one (2:1) or more, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2016

Gas turbine engine

A gas turbine engine with a compressor rotor having compressor impulse blades that delivers gas at supersonic conditions to a stator. The stator includes a one or more aerodynamic ducts that each have a converging portion and a diverging portion for deceleration of the selected gas to subsonic conditions and to deliver a high pressure oxidant containing gas to flameholders. The flameholders may be provided as trapped vortex combustors, for combustion of a fuel to produce hot pressurized combustion gases. The hot pressurized combustion gases are choked before passing out of an aerodynamic duct to a turbine. Work is recovered in a turbine by expanding the combustion gases through impulse blades. By balancing the axial loading on compressor impulse blades and turbine impulse blades, asymmetrical thrust is minimized or avoided.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2016

Supersonic compressor

A supersonic compressor including a rotor to deliver a gas at supersonic conditions to a diffuser. The diffuser includes a plurality of aerodynamic ducts that have converging and diverging portions, for deceleration of gas to subsonic conditions and then for expansion of subsonic gas, to change kinetic energy of the gas to static pressure. The aerodynamic ducts include vortex generating structures for controlling boundary layer, and structures for changing the effective contraction ratio to enable starting even when the aerodynamic ducts are designed for high pressure ratios, and structures for boundary layer control. In an embodiment, aerodynamic ducts are provided having an aspect ratio of in excess of two to one, when viewed in cross-section orthogonal to flow direction at an entrance to the aerodynamic duct.

42 ENGINEERING↗
DOE OSTI2016

Fermilab Recycler Collimation System Design

To provide 700 kW proton beams for neutrino production in the NuMI facility, we employ slip stacking in the Recycler with transfer to the Main Injector for recapture and acceleration. Slip stacking with 12 Booster batches per 1.33 sec cycle of the Main Injector has been implemented and briefly tested while extensive operation with 8 batches and 10 batches per MI cycle has been demonstrated. Operation in this mode since 2013 shows that loss localization is an essential component for long term operation. Beam loss in the Recycler will be localized in a collimation region with design capability for absorbing up to 2 kW of lost protons in a pair of 20-Ton collimators (absorbers). This system will employ a two stage collimation with a thin molybdenum scattering foil to define the bottom edge of both the injected and decelerated-for-slipping beams. Optimization and engineering design of the collimator components and radiation shielding are based on comprehensive MARS15 simulations predicting high collimation efficiency as well as tolerable levels of prompt and residual radiation. The system installation during the Fermilab 2016 facility shutdown will permit commissioning in the subsequent operating period.

43 PARTICLE ACCELERATORS↗
DOE OSTI2017

Evaluation of the Inertial Response of Variable-Speed Wind Turbines Using Advanced Simulation: Preprint

In this paper, we focus on the temporary frequency support effect provided by wind turbine generators (WTGs) through the inertial response. With the implemented inertial control methods, the WTG is capable of increasing its active power output by releasing parts of the stored kinetic energy when the frequency excursion occurs. The active power can be boosted temporarily above the maximum power points, but the rotor speed deceleration follows and an active power output deficiency occurs during the restoration of rotor kinetic energy. In this paper, we evaluate and compare the inertial response induced by two distinct inertial control methods using advanced simulation. In the first stage, the proposed inertial control methods are analyzed in offline simulation. Using an advanced wind turbine simulation program, FAST with TurbSim, the response of the researched wind turbine is comprehensively evaluated under turbulent wind conditions, and the impact on the turbine mechanical components are assessed. In the second stage, the inertial control is deployed on a real 600-kW wind turbine, the three-bladed Controls Advanced Research Turbine, which further verifies the inertial control through a hardware-in-the-loop simulation. Various inertial control methods can be effectively evaluated based on the proposed two-stage simulation platform, which combines the offline simulation and real-time hardware-in-the-loop simulation. The simulation results also provide insights in designing inertial control for WTGs.

17 WIND ENERGY↗
DOE OSTI2017

Real-Time Digital Simulation of Inertial Response with Hardware-in-the-Loop Implementation on the CART3 Wind Turbine at the National Wind Technology Center

With increasing penetrations of wind power on electric grids, the stability and reliability of interconnected power systems may be impacted. In some countries that have developed renewable energy sources and systems, grid codes have been revised to require wind power plants (WPPs) to provide ancillary services to support the power system frequency in case of severe grid events. To do this, wind turbine generators (WTGs) should be deloaded to reserve a certain amount of active power for primary frequency response; however, deloading curtails annual energy production, and the market for this type of service needs to be further developed. In this report, we focus on the temporary frequency support provided by WTGs through inertial response. WTGs have potential to provide inertial response, but appropriate control methods should be implemented. With the implemented inertial control methods, wind turbines are capable of increasing their active power output by releasing some of their stored kinetic energy when a frequency excursion occurs. Active power can be temporarily boosted above the maximum power points, after which the rotor speed decelerates, and subsequently an active power output reduction restores the kinetic energy. In this report, we develop two types of models for wind power systems: the first is common, based on the wind power aerodynamic equation, and the power coefficient can be regressed using nonlinear functions; the second is much more complicated, wherein the wind turbine system is modeled using the Fatigue, Aerodynamics, Structures, and Turbulence Modeling (FAST) tool with several degrees of freedoms. A nine-bus test power system is built in Simulink and the Real-Time Digital Simulator, respectively, which are used to evaluate the frequency support performance of the WPPs. We implement two distinct types of inertial control methods in the modeled wind turbines: frequency-based inertial control (FBIC) and stepwise inertial control (SIC). We compare the performances of the two methods in terms of their frequency nadirs, rates of change of frequency, and recovery times. We conclude the results under various wind speeds and penetration cases, which provide insight into designing the inertial response of WTGs. Further, we discuss the impact of the parameters on the performance of the inertial control methods. We evaluate both the scaling factors for the FBIC method and the slope values for the TLIC methods. The simulation work shows the characteristics of different inertial responses compared to conventional synchronous generators. Based on the simulation results, we modify, improve, and test the inertial control methods under a more realistic wind turbine model based on FAST. We then validate the inertial responses under highly turbulent wind conditions generated by TurbSim, and we examine their influences on the turbine mechanical components. The extensive simulation proves the effectiveness of the proposed inertial control methods as well as the nine-bus test power system. We then reconsider the parameters. We rebuild the same test power system using Real time Simulator Computer Aided Design (RSCAD), and we implement the inertial control methods in the real Controls Advanced Research Turbine (CART3), which is prepared for the hardware-in-the-loop field-test simulation. After the setups for the hardware and software hybrid simulation platform are complete, the inertial response is further tested on a real wind turbine for the first time, in which CART3 release the controlled inertial response against the emulated frequency excursion, provided by the real-time simulated power system test bed in RTDS.

17 WIND ENERGY↗
DOE OSTI2015

Low Adiabat Compression of Liquid Deuterium Filled Cylindrical Liners to 0.1?2 Gbar.

We report on experiments where cylindrical beryllium liners filled with liquid deuterium were compressed to extreme pressure and density with current pulse shaping. In one set of experiments the pressure at stagnation is inferred to be & 100 Mbar using penetrating radiography. A peak liner convergence ratio (initial radius over final radius) of 7.6 was measured resulting in an average deuterium density of 10 g=cm 3 and areal density of 0.45 g=cm 2 . The stagnation shock propagating radially outward through the liner wall was directly measured with a strength of ≈ 120 Mbar. In a second set of experiments the liner was imploded to a peak convergence of 19 resulting in a density of 55 g=cm 3 and areal density of 0.5 g=cm 2 . The pressure at stagnation in this experiment is estimated to be 2 Gbar. This platform enables the study of high-pressure, high-density, implosion deceleration and stagnation dynamics at spatial scales that are readily diagnosable (R ~ 0.1 -- 0.4 mm). Thus, these experiments are directly relevant to both Inertial Con nement Fusion and the study of material properties under extreme conditions.

Knapp, Patrick↗
DOE OSTI2017

Real-Time Measurement of Machine Efficiency during Inertia Friction Welding.

Process efficiency is a crucial parameter for inertia friction welding (IFW) that is largely unknown at the present time. A new method has been developed to determine the transient profile of the IFW process efficiency by comparing the workpiece torque used to heat and deform the joint region to the total torque. Particularly, the former is measured by a torque load cell attached to the non-rotating workpiece while the latter is calculated from the deceleration rate of flywheel rotation. The experimentally-measured process efficiency for IFW of AISI 1018 steel rods is validated independently by the upset length estimated from an analytical equation of heat balance and the flash profile calculated from a finite element based thermal stress model. The transient behaviors of torque and efficiency during IFW are discussed based on the energy loss to machine bearings and the bond formation at the joint interface.

42 ENGINEERING↗
DOE OSTI2017

REDTOP Beam Modeling for Raised Transition Energy and Third Integer Resonance Extraction

To explore physics beyond the Standard Model, the experiment called Rare Eta Decays with a TPC for Optical Photons (REDTOP) is in its proposal stage at Fermi National Accelerator Laboratory to study η decays. The existing delivery ring will destabilize the beam as it is decelerated for REDTOP’s use, so modifications to the magnet arrangement have been proposed and must be simulated.This work focused on using MAD-X to model the introduction of new quadrupoles and sextupoles to raise the transition energy and shape the beam for extraction.

43 PARTICLE ACCELERATORS↗
DOE OSTI2018

How Driving Volatility in Time to Collision Relates to Crash Severity in a Naturalistic Driving Environment

The sequence of instantaneous driving decisions and its variations, known as driving volatility, can be a leading indicator of unsafe driving practices. The research issue is to characterize volatility in instantaneous driving decisions in longitudinal and lateral direction and to seek an understanding of how driving volatility relates to crash severity. By using a unique real-world naturalistic driving database from the SHRP 2, a test set of 671 crash events featuring around 0.2 million temporal samples of real-world driving are analyzed. Based on different driving performance measures, 16 different volatility indices are created. The volatility indices are then linked with individual crash events including information on crash severity, drivers’ pre-crash maneuvers and behaviors, secondary tasks and durations, and other factors. As driving volatility prior to crash involvement can have different components, an in-depth analysis is conducted using the aggregate as well as segmented (based on time to collision) real-world driving data. To account for the issues of observed and unobserved heterogeneity, fixed and random parameter ordered models with heterogeneity in parameter means are estimated. The findings suggest that greater driving volatility (both in longitudinal and lateral direction) prior to crash occurrence increases the likelihood of police reportable or severe crash events. Importantly, compared to the effect of volatility in longitudinal acceleration on crash outcomes, the effect of volatility in longitudinal deceleration is significantly greater in magnitude. Methodologically, the random parameter models with heterogeneity-in-means significantly outperformed both the fixed parameter and random parameter counterparts. The relevance of the findings to the development of proactive behavioral countermeasures for drivers is discussed.

Wali, Behram↗
DOE OSTI2015

Data Driven Fuel Efficient Driving Behavior Feedback for Fleet Vehicles

Dependency of the transport sector on fossil fuels is encouraging a significant amount of research in to improving fuel efficiency in vehicles. Three primary techniques are identified for vehicle fuel efficiency improvement: 1) vehicle technology improvements such as drivetrain improvements, 2) traffic infrastructure improvements such as traffic flow management and route selection, and 3) driver behavior changes such as acceleration and deceleration profiles. Out of the 3 techniques, driver behavior changing has the least implementation cost and is able to provide immediate results. Thus, this paper presents a fuel efficient driving behavior identification and feedback architecture that is specific to fleet vehicles. The presented method utilizes historical data from fleet drivers on specific routes and generates fuel optimal velocity profiles that do not affect travel time. The identified velocity profile is the prompted to the driver via a low-cost plug-and-play style un-obstructive display. The display uses an intuitive and easily understandable visualization to prompt drivers on fuel efficient velocity. The presented architecture was tested on the Idaho National Laboratory (INL) bus fleet in real-world driving conditions and was shown to be able to increase the fuel economy by 9% and 20% in two different driving scenarios.

99 GENERAL AND MISCELLANEOUS↗
DOE OSTI2019

Evaluating Safety with Automated Vehicles at Signalized Intersections: Application of Adaptive Cruise Control in Mixed Traffic

Automated Vehicles (AV) can potentially improve the performance of transportation system by reducing human errors and enhancing mobility and safety. In lower levels of automation, humans are still controlling the vehicle and receiving some advisory information regarding their surrounding environment. This paper investigates the safety impact of low and high levels of AVs, and their interaction with conventional human-driven vehicles at intersections. In order to enhance our understanding of the future interactions between conventional vehicles with AVs, we developed a framework to simulate the mixed traffic environment. Different market penetration scenarios are simulated using VENTOS (VEhicular NeTwork Open Simulator) software. A modified Wiedemann car-following model was calibrated to represent the behavior of human drivers of both conventional and low-level AVs, while an Adaptive Cruise Control model was used to represent high-level AVs. Notably, this study investigates purely the automation improvement in the system. We modified the acceleration and deceleration regimes of the Wiedemann model and tuned it by harnessing real-world connected vehicle data. Next, the simulation was calibrated utilizing two measures of driving volatility to ensure it closely represents the volatility measures of the real-world data. To evaluate the safety performance of a representative intersection under different scenarios, the number of longitudinal conflicts and driving volatility are used as surrogate safety indicators. The results reveal that increase in market penetration rate of LAVs and HAVs substantially improves intersection safety performance by reducing the number of conflicts and driving volatility.

Arvin, Ramin↗
DOE OSTI2019

First Test Results of Superconducting Twin Axis Cavity for ERL Applications

Superconducting cavities with two beam pipes had been proposed in the past for energy recovery linac applications. The relatively complex geometry of those cavities presented a serious challenge for fabrication and surface processing. Main concerns have now been overcome with the production and successful RF testing of a new elliptical twin-axis cavity proposed by Jefferson Lab and optimized by the Center for Accelerator Science at Old Dominion University in the frame of a DoE accelerator stewardship program. The cavity design provides uniform accelerating or decelerating fields for both beams. This paper describes the cavity design, fabrication experience, and the first cold RF test results and explores potential applications especially for Jefferson Lab s EIC (JLEIC).

Park, H.-K.↗
DOE OSTI2022

Magnetically Levitated and Constrained Flywheel Energy Storage System

The concept of using linear induction motors to lift, constrain, accelerate, and decelerate a large-scale flywheel is proposed, and some of the advantages are investigated. Calculations for a Magnetically Levitated Energy Storage System (MLES) are performed that compare a single large scale MLES with a current state of the art flywheel energy storage system in order to show the relative differences and advantages of such a system. The system that is used for comparison is a typical Beacon Power flywheel energy system. This is currently one of the state-of-the-art flywheel energy storage systems and so it can be used to provide a basic data set to compare to an MLES system.

VanOsdol, John↗
DOE OSTI2022

PERLE A ‘STEPPING STONE’ FOR THE NEXT GENERATION ERLS

PERLE (Powerful ERL for Experiments) is a novel Energy Recovery Linac (ERL) test facility, which has been designed to validate choices for a 50 GeV ERL foreseen in the design of the LHeC and the FCC-eh, and to later serve a set of dedicated nuclear and particle physics experiments. Its main thrust is to probe high current, continuous wave (CW), multi-pass operation with superconducting cavities at 802 MHz (and perhaps testing other frequencies of interest). With very high transient beam power (~10 MW), PERLE offers an opportunity for controllable study of every beam dynamic effect of interest in the next generation of ERL design and become a ?stepping stone? between present state-of-art 1 MW ERLs and future 100 MW scale applications. PERLE design features flexible momentum compaction lattice architecture for six vertically stacked return arcs and a high current, 7 MeV, photo-injector. With only one pair of four cavity cryomodules, 500 MeV beam energy can be reached in three re-circulation passes, with beam currents of about 20 mA. The beam is decelerated in three consecutive passes back to the injection energy. Work on the engineering design of PERLE has just begun.

Bogacz, S.↗
DOE OSTI2022

PERLE AT ORSAY. LATTICE DESIGN OF 250MeV VERSION

The PERLE (Powerful Energy Recuperation Linac Experiment) collaboration is developing a high power (with a current of up to 20mA of 500MeV electrons) an energy recuperation linac machine with three acceleration and three deceleration passes through two cryo-modules. Here we present the design of the first stage of this machine with one cryo-module that would demonstrate the six-passes operation at a high current with a maximal energy of 250MeV. All the magnets and the cryo-module are chosen to be compatible with both stages to minimise the costs of upgrade to the final one. The low-beta experimental areas are foreseen in a twelve meters straight section at 250 MeV.

Fomin, Oleksiy↗