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Status of GTA Gear Inspection after Testing in Sodium
The Mechanisms Engineering Test Loop (METL) is an intermediate-scale liquid metal experimental facility that provides purified reactor-grade (R-grade) sodium to various experimental test vessels. In these test vessels, components that are required to operate in an advanced fast reactor can be tested in a prototypical sodium environment. Experiments conducted in METL significantly assist in the development and maturation of systems and components for advanced reactors. The METL facility consists of multiple test segments including: a purification and diagnostic loop (cold trap was designed after EBR-II), two 18” diameter test vessels with 150 L capacities capable of operating in static or dynamic flow at 538°C, two 28” diameter test vessels with 644 L capacities capable of operating in static or dynamic flow at 650°C, a 3,180 L dump tank with 21 instrumentation ports, and the infrastructure to expand capacity in the future.
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Additional Data Focused on Phase 1 Geared Toward Computational Fluid Dynamics (CFD) validation
A new validation campaign was developed within the Offshore Code Comparison Collaboration, Continued, with Correlation and unCertainty (OC6) to better understand the complex interactions between components of a floating wind system (e.g., columns, pontoons, etc.) in a more generic sense, and to validate modeling approaches for a variety of floating designs. A set of cylinders based on the Offshore Code Comparison Collaboration Continuation (OC4)-DeepCwind semidesign were tested under wave loading, both individually and in different combinations (including the attachment of heave plates of different sizes). The cylinders were held rigid, and pressure sensors were used to measure the distributed loading on the structures, while load cells measured the total integrated hydrodynamic loads.
Multi-Objective Cycle Optimization of an Integrally Geared Waste Heat Recovery Unit for a Combined Cycle Power System
This paper has presented the cycle design and optimization details for a sCO2-based WHRS targeting the Solar Turbines Titan 130. The PreheatSR cycle layout was chosen to effectively address the issue of acid dew point corrosion and ensure high system performance is not significantly impacted by use of alternative fuels. The optimization process discussed uses a multi-objective optimization to discover a series of optimal cycle configurations given ambient temperature variability for a chosen site location while considering the initial capital cost of the cycle components. Cycle models built that incorporated off-design methods for the heat exchangers and turbomachinery allowed for the investigation of cycle operation that maximizes power output for individual cycle conditions. The resulting Pareto front serves as a guide for how to configure the WHRS cycle for the highest yearly energy extracted for a given investment.
Gearing Up for 2030: Building the Offshore Wind Supply Chain and Workforce Needed to Deploy 30 GW and Beyond
This webinar addresses the current state and future needs of the U.S. offshore wind energy workforce and supply chain. During this webinar, National Renewable Energy Laboratory researchers Matt Shields and Jeremy Stefek will present new research on the challenges of producing thousands of offshore wind energy technology components while creating tens of thousands of U.S. jobs - and the solutions that can help meet those challenges. Topics covered in the webinar include port facilities, vessels, component manufacturing, trades and roles in the industry, workforce development and training, and the coordination of supply chain and workforce efforts between states and regions.
Gearbox assembly
A gearbox assembly includes a first gear coupled to a first shaft, a second gear coupled to a second shaft, and a plurality of planet gears that mesh with the first gear and the second gear. The first shaft includes a first shaft stiff portion and a first shaft flexible portion that includes a greater flexibility than a flexibility of the first shaft stiff portion such that the first gear moves in a radial direction. The second shaft includes a second shaft stiff portion and a second shaft flexible portion that includes a greater flexibility than a flexibility of the second shaft stiff portion such that the second gear moves in the radial direction. The first gear and the second gear move to distribute loads substantially equally on the plurality of planet gears.
Results of ISO/TS 6336-22 Evaluating Full Contact Zone
ISO/TS 6336-22 (Calculation of load capacity of spur and helical gears - Part 22: Calculation of micropitting load capacity) is the ISO technical specification containing a proposal for calculations of the risk of micropitting in gear sets. Micropitting is a Hertzian fatigue phenomenon that appears as ultra-fine cracking and pitting on the flanks of gear teeth. Since progressive micropitting can lead to macropitting and flank damage, critical applications such as wind turbines, marine drives, and high-speed gear drives seek to accurately predict whether their designs are susceptible to this damage. ISO/TS 6336-22 assesses micropitting risk through a safety factor which is calculated as the minimum specific film thickness in the contact zone divided by a permissible specific film thickness. In the previous paper, the calculations were performed using the simplified method (Method B) that evaluates points on the path of contact. This was done for three gear sets that experienced micropitting in operation. The minimum specific film thickness for the two field cases was very high, which indicates that the gears were operating in the full elastohydrodynamic lubrication (EHL) regime. A more accurate calculation for these cases (Method A) calculates the specific film thickness across the entire contact zone. This paper applies this Method to the case study from the previous paper. The results are compared to micropitting observed in operation. Results are also compared to the results of the previous paper. Conclusions are made regarding the accuracy of both Methods compared to the field cases and relative to each other.
Investigating the Impact of Power-Take-Off System Parameters and Control Law on a Rotational Wave Energy Converter’s Peak-to-Average Power Ratio Reduction
Due to the irregular nature of real waves, the power captured in a wave energy converter (WEC) system is highly variable. This is an important barrier to the effective use of WECs. To address this challenge, this study focuses on a rotational WEC power-take-off system in which high-speed and high-efficiency generators along with a torque/power smoothing inertia element can be effectively utilized. In the first phase of this study, the U.S. Department of Energy’s reference model 3 (WEC-Sim RM3; two-body point absorber), along with a slider-crank WEC, were integrated for linear to rotational conversion. Relative motion between the float and spar in RM3 was the driving force for this slider-crank WEC, which is connected to a motor/generator set through a gearbox. RM3 geometry was scaled down by 25 times to work within the limits of the physical motor/generator set used in the experimentation. Once the integration in a hardware-in-the-loop simulation environment was successfully completed, data on the peak-to-average power ratio was collected for various wave conditions including regular and irregular waves. The control algorithm designed to keep the system in resonance with waves was able to maintain relatively high speed depending on the specific gear ratio and wave period. Initial results with hardware-in-the-loop simulations reveal that gear ratio and crank radius have a strong impact on the peak-to-average power ratio. In addition, it was found that output power from the generator was maximized at a larger gear ratio, as the crank radius was increased.
Optical matter machines: angular momentum conversion by collective modes in optically bound nanoparticle arrays
The creation of optically powered self-assembling nano-to-meso-scale machines that do work is a long-standing goal in photonics. We demonstrate an optical matter (OM) machine that converts the spin angular momentum (SAM) of light into orbital angular momentum (OAM) to do mechanical work. The specific OM machine we study is based on a sixfold symmetric hexagonally ordered nanoparticle array that operates as an OM “gear” that is assembled and made to rotate in a circularly polarized Gaussian beam. The rotational symmetry of the OM gear leads to a selection rule for the allowed scattering modes based on their angular momentum. Electrodynamics calculations show that the collective scattering modes with the largest angular momentum scatter strongly in the transverse direction. Simulations and experiments show that the angular momentum that accompanies the scattered light causes a “negative torque” response on the OM gear and drives a “probe” particle placed outside the OM gear around the gear in an asymmetric force field analogously to Brownian ratchets. The gear–probe OM machine concept can be expanded to applications in nanofluidics and particle sorting.
Gripper Test Assembly Status Report (FY2020)
Refueling systems for fast reactors are designed to handle fresh and used core assemblies (fuel, reflector, and shield core assemblies) within the reactor vessel in an opaque coolant environment without visual reference. These refueling machines are designed to work in a sodium (or other fast reactor coolant) and argon vapor space environment and are engineered with the rotatable plug system to allow for the movement of fresh and spent fuel into and out of the reactor core. The refueling machines are a critical component in any reactor and thus need to undergo extensive testing in a prototypic environment to ensure that they will meet all of the system functions and requirements. Argonne has developed an innovative compact refueling system design for the Advanced Fast Reactor-100 that is based upon some mechanisms used in previous reactor designs, such as the U.K.’s Prototype Fast Reactor (PFR) and some mechanisms that have not been used in sodium. This compact refueling machine supports the reduction in size of the AFR-100’s reactor vessel, and if fully developed, would support and inform the development of the in-vessel refueling machines for such commercial reactors as the GEH PRISM reactor plant, the ARC Clean Energy’s ARC-100 reactor, and the Natrium reactor, among others. This refueling system is a vital component of a fast reactor that supports reducing the cost of the reactor and increasing its reliability. During the development of the compact fuel handling machine conceptual design for the AFR-100, a lack of testing data for many mechanical components in sodium under typical in-reactor loads and conditions was discovered. The reduction in lifetime of the various mechanical components in the liquid sodium environment needs to be quantified versus the calculated component lifetimes under normal conditions in the testing while they are subjected to typical loading profiles experienced in the past. The Gripper Test Assembly discussed here includes a full-size gripper device with appropriate mechanical features that will be tested in sodium to provide this testing data. The Gripper Test Assembly is used to test various mechanical fuel handling components submerged in high temperature liquid sodium. These mechanisms are gears, bearings, gripper jaws and head, universal joints and shafts, ball screws, among others. These components will be tested under the typical sodium environmental conditions experienced during refueling operations with appropriate loading conditions that simulate the removal and insertion of core assemblies into a fast reactor grid plate structure. This Gripper Test Assembly is the second in a series of refueling system mechanisms developed for testing in sodium. The first test assembly is the Gear Test Assembly (GTA) which was used to test the performance of gears and bearings operating in sodium. Because of the successful testing conducted with the GTA, it was decided to continue with the development of the Gripper Test Assembly which uses the same gears and bearings tested in GTA. Using the data collected during operation of this gripper test assembly, lifetime reduction factors of the various mechanical components can be calculated for the material combinations selected. These lifetime reduction factors can be used in the design of future mechanical systems which operate in these environments to accurately predict component end of life. In addition, an understanding of the ability of these components and mechanisms to operate under-sodium with the chosen materials will be accomplished. Again, this Gripper Test Assembly is the follow-on test article to the Gear Test Assembly which was testing the ability of gears and bearings operating in a sodium environment. Once fabricated and qualified, it will be tested in the Mechanism Engineering Test Loop (METL) facility located in Building 308 at Argonne National Laboratory.
Results of ISO/TS 6336-22 Evaluating Full Contact Zone: Preprint
ISO/TS 6336-22 (Calculation of load capacity of spur and helical gears — Part 22: Calculation of micropitting load capacity) is the ISO technical specification containing a proposal for calculations of the risk of micropitting in gear sets. Micropitting is a Hertzian fatigue phenomenon that appears as ultra-fine cracking and pitting on the flanks of gear teeth. Since progressive micropitting can lead to macropitting and flank damage, critical applications such as wind turbines, marine drives, and high-speed gear drives seek to accurately predict whether their designs are susceptible to this damage. ISO/TS 6336-22 assesses micropitting risk through a safety factor which is calculated as the minimum specific film thickness in the contact zone divided by a permissible specific film thickness. In the previous paper, the calculations were performed using the simplified method (Method B) that evaluates points on the path of contact. This was done for three gear sets that experienced micropitting in operation. The minimum specific film thickness for the two field cases was very high, which indicates that the gears were operating in the full elastohydrodynamic lubrication (EHL) regime. A more accurate calculation for these cases (Method A) calculates the specific film thickness across the entire contact zone. This paper applies this Method to the case study from the previous paper. The results are compared to micropitting observed in operation. Results are also compared to the results of the previous paper. Conclusions are made regarding the accuracy of both Methods compared to the field cases and relative to each other.
Results of ISO/TS 6336-22 Evaluating Full Contact Zone
ISO/TS 6336-22 (Calculation of load capacity of spur and helical gears - Part 22: Calculation of micropitting load capacity) is the ISO technical specification containing a proposal for calculations of the risk of micropitting in gear sets. Micropitting is a Hertzian fatigue phenomenon that appears as ultra-fine cracking and pitting on the flanks of gear teeth. Since progressive micropitting can lead to macropitting and flank damage, critical applications such as wind turbines, marine drives, and high-speed gear drives seek to accurately predict whether their designs are susceptible to this damage. ISO/TS 6336-22 assesses micropitting risk through a safety factor which is calculated as the minimum specific film thickness in the contact zone divided by a permissible specific film thickness. In the previous paper, the calculations were performed using the simplified method (Method B) that evaluates points on the path of contact. This was done for three gear sets that experienced micropitting in operation. The minimum specific film thickness for the two field cases was very high, which indicates that the gears were operating in the full elastohydrodynamic lubrication (EHL) regime. A more accurate calculation for these cases (Method A) calculates the specific film thickness across the entire contact zone. This paper applies this Method to the case study from the previous paper. The results are compared to micropitting observed in operation. Results are also compared to the results of the previous paper. Conclusions are made regarding the accuracy of both Methods compared to the field cases and relative to each other.
Focal Fisheries Requirements for Floating Offshore Wind Co-Design in the Gulf of Maine and the Mid-Atlantic Bight
Floating offshore wind is an emerging renewable energy technology in U.S. waters and globally. Floating offshore wind technology is more complex than fixed-bottom installations, requiring platforms, moorings, and power cables that take up a larger footprint, both in the water column and along the seafloor. This complexity affects opportunities for compatibility between floating offshore wind and other ocean users, particularly fishermen, whose fishing gear also takes up space in the water column and along the seafloor. This report describes the results of semi-structured interviews with key fishing informants from two focal fisheries: (1) Gulf of Maine lobster (fixed gear) and (2) Mid-Atlantic Bight pelagic longline and recreational tuna (mobile gear). A total of six fishermen were interviewed: four from the Gulf of Maine and two from the Mid-Atlantic Bight. The interviews were designed to elicit information and opinions on the co-design of marine space for particular fishing gear and floating offshore wind infrastructure. Here, we provide an overview of participant fishing experience, the spatial requirements of specific gear types, self-reported comfort levels in different fishing scenarios, and concerns about accessing and operating within floating offshore wind arrays. This summary of fishermen s concerns around floating offshore wind infrastructure can guide future co-existence conversations.
Instantaneous mesh load factor ( K γ ) measurements in a wind turbine gearbox using fiber-optic strain sensors
The mesh load factor, K γ , describes how loads are shared between planet gears and has become one of the key design challenges in modern wind turbine gearboxes. Planet load sharing directly impacts tooth root stresses, a critical driver of torque density and gearbox reliability. Experimental evaluation of K γ is typically performed from sun gear tooth root strain gauge measurements, which are complex. Furthermore, such measurements can only provide an average value of load sharing. The present study describes an alternative method to evaluate the mesh load factor in wind turbine gearboxes based on fiber-optic strain sensors installed on the outer surface of the fixed ring gear. We present the results of an extensive measurement campaign to evaluate this novel sensing solution installed on the input planetary stage of a 2-MW wind turbine gearbox at the National Renewable Energy Laboratory's Flatirons Campus (Colorado, USA). The number of strain sensors on the ring gear was selected as an integer multiple of the number of planets, which has enabled an instantaneous evaluation of the mesh load factor. The effect of operating conditions on the planet load-sharing behavior of the gearbox has been investigated. The mesh load factor measured for operating conditions close to rated was below 1.05, well below IEC 61400-4 standard requirements.
Bioeconomic benefits of managing fishing effort in a coexisting small- and large-scale fishery game
Abstract Fishing systems provide employment, income generation, poverty alleviation, and food security. The coexistence of small-scale fisheries (SSFs) and large-scale fisheries (LSFs) increases management complexity. Management actions have ecological and social implications that must be addressed carefully. We applied a bioeconomic game-theoretical model to the four-gear mullet fishery in southern Brazil—one industrial LSF (purse seine) and three artisanal SSFs (gillnet, beach seine, and drift net). All fishing gears target adult individuals during mullet's reproductive migration. First, we explored whether the current fishing efforts of all fishing gears could persist over time. Second, we investigated their interactions through a non-cooperative game. Finally, we studied the response of these interactions when fishing effort was restricted. We found that when the current fishing effort was maintained, the stock reduced to 26.4% of its capacity in 25 years. In addition, under non-cooperation, the traditional beach seine fleet exited the fishery. Interestingly, the constrained scenario had a coexistence output with increasing values for the final stock size and the per capita labour income, suggesting that limiting fishing effort can maintain all fishing gears in the fishery with social and ecological benefits.
Linear differential
Apparatuses and methods of operating a linear differential (100, 600) are described herein. The linear differential (100, 600) contains a slide portion (102) with parallel right-hand and left-hand threaded rods (112, 114). Threaded onto the right-hand and left-hand threaded rods (112, 114) and attached to the slide portion (102) are right-hand and left-hand gears (116, 118). Meshed between the right-hand and left-hand gears (116, 118) and also attached to the slide portion (102) is a driven gear (200). An end effector (104) is attached to the driven gear (200) and is configured to translate along a translation axis (110) and rotate around a rotation axis (120).