A Bearingless Motor with Passive Electrodynamic Suspension in Axial Direction

This paper investigates the vibration which caused by electromagnetic on the stator end-winding of the large dry submersible motor. Firstly, the electromagnetic field which included transition state and steady state is researched by 3-D FEM. Secondly, the electromagnetic force which lead to vibrations of end-winding is calculated by numerical method, it can be obtained that where endured the largest force density along the slant part of end-winding. Finally, the radial displacement and the axial displacement of the slant part which caused by vibrations is studied, the analysis results show that the axial displacement is larger than the amplitude of radial displacement. It indicates that the slant part of end-winding will be more easily damaged at axial direction than radial direction.

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Random pore structure and REV scale flow analysis of engine particulate filter based on LBM

Open Physics ◽

10.1515/phys-2020-0208 ◽

2020 ◽

Vol 18 (1) ◽

pp. 881-896

Author(s):

Chunrui Wu ◽

Tiechen Zhang ◽

Jiale Fu ◽

Xiaori Liu ◽

Boxiong Shen

Keyword(s):

Single Channel ◽

Flow Analysis ◽

Flow Characteristics ◽

Axial Direction ◽

Particulate Filter ◽

Random Structure ◽

Structure Generation ◽

Inlet Flow ◽

Random Structures ◽

Boltzmann Method

Abstract In this article, lattice Boltzmann method (LBM) is used to simulate the multi-scale flow characteristics of the engine particulate filter at the pore scale and the representative elementary volume (REV) scale, respectively. Four kinds of random wall-pore structures are considered, which are circular random structure, square random structure, isotropic quartet structure generation set (QSGS), and anisotropic QSGS, with difference analysis done. In terms of the REV scale, the influence of different inlet flow velocities and wall permeabilities on the flow in single channel is analyzed. The result indicates that the internal seepage laws of random structures constructed in this article and single channel are in accordance with Darcy’s law. Circular random structure has better permeability than square random structure. Isotropic QSGS has better fluidity than anisotropic one. The flow in single channel is similar to Poiseuille flow. The flow lines in the channel are complicated and a large number of vortices appear at the ends of channel with high inlet flow rate. With the increase of inlet velocity, the static pressure in channel gradually increases along the axial direction as well as the seepage velocity. The temperature field in the channel becomes more uniform as the flow velocity increases, and the higher temperature distribution appears on the wall of the porous media.

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Study on the atomization zones of the nozzle in the processes of material primary processing

Journal of Intelligent & Fuzzy Systems ◽

10.3233/jifs-189604 ◽

2021 ◽

pp. 1-8

Author(s):

Nan Pan ◽

Junbin Qian ◽

Chengjun Zhao

Keyword(s):

Axial Direction ◽

Liquid Distribution ◽

Primary Processing ◽

Nozzle Injection ◽

Injection Zone ◽

Liquid Atomization ◽

Whole Space ◽

Simulation And Experiment ◽

Jet Nozzle ◽

Atomization Zone

It can divide the atomization effect in the direction of the nozzle axial injection into the jet area and the non-jet area by using the second crushing theory. On this basis, according to the feed liquid atomization particles discrete degree index of characteristics particle size of feed liquid atomization, it divides the injection zone into the atomization area and the diffusion area, so as to realize the axial direction of jet nozzle injection zone, atomization zone and the diffusion zone accurately. Simulation and experiment are used to verify the three zones of atomization nozzle. The division of three zones drives the study from the whole space of liquid distribution in the roller to atomization zone, clears the key zone of the roller in tobacco primary processing, and provides a basis for further work.

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Probing bacterial cell wall growth by tracing wall-anchored protein complexes

Nature Communications ◽

10.1038/s41467-021-22483-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yi-Jen Sun ◽

Fan Bai ◽

An-Chi Luo ◽

Xiang-Yu Zhuang ◽

Tsai-Shun Lin ◽

...

Keyword(s):

Cell Wall ◽

Cell Shape ◽

Bernoulli Shift ◽

Protein Complexes ◽

Axial Direction ◽

Cell Wall Growth ◽

Flagellar Motors ◽

Shift Map ◽

Dynamic Assembly ◽

Wall Growth

AbstractThe dynamic assembly of the cell wall is key to the maintenance of cell shape during bacterial growth. Here, we present a method for the analysis of Escherichia coli cell wall growth at high spatial and temporal resolution, which is achieved by tracing the movement of fluorescently labeled cell wall-anchored flagellar motors. Using this method, we clearly identify the active and inert zones of cell wall growth during bacterial elongation. Within the active zone, the insertion of newly synthesized peptidoglycan occurs homogeneously in the axial direction without twisting of the cell body. Based on the measured parameters, we formulate a Bernoulli shift map model to predict the partitioning of cell wall-anchored proteins following cell division.

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Experimental and numerical investigations on novel models for mechanical behaviors of the elastic ring in aero-engine

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1177/09544062211013066 ◽

2021 ◽

pp. 095440622110130

Author(s):

Zhong Luo ◽

Lei Li ◽

Yang Yang ◽

Xiaojie Hou ◽

Jiaxi Liu ◽

...

Keyword(s):

3D Model ◽

Maximum Stress ◽

Simple Structure ◽

Experimental Testing ◽

Axial Direction ◽

Elastic Ring ◽

Load Range ◽

Aero Engine ◽

Stiffness Characteristics ◽

First Time

The elastic ring is widely used in elastic support structures of aero-engine because of its simple structure and convenient manufacturing. In this paper, two elastic ring models, 3D and 2D models, are proposed, where the fillets between the bulges and ring are considered. The 2D model is more efficient for the calculation of stiffness characteristics. The 3D model can be used to obtain the maximum stress position in the axial direction. Then the experimental testing is carried out to verify the accuracy and effectiveness of the proposed models. Based on the proposed models, the stiffness nonlinearity and critical load of the elastic ring are found for the first time, which can be used to determine the normal working load range. Moreover, the elastic ring models with and without fillets are developed, and the effect of the fillets on stress is discussed. The results show that the stress is reduced by considering the fillets, which are not considered in the existing literature.

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Optimized Growth and Laser Application of Yb:LuAG Single-Crystal Fibers by Micro-Pulling-Down Technique

Crystals ◽

10.3390/cryst11020078 ◽

2021 ◽

Vol 11 (2) ◽

pp. 78

Author(s):

Anye Wang ◽

Jian Zhang ◽

Shuai Ye ◽

Xiaofei Ma ◽

Baiyi Wu ◽

...

Keyword(s):

Single Crystal ◽

High Power ◽

Slope Efficiency ◽

Continuous Wave ◽

Beam Quality ◽

Axial Direction ◽

Optical Quality ◽

Central Wavelength ◽

High Power Lasers ◽

Crystal Fibers

Single-crystal fibers (SCFs) have a great application potential in high-power lasers due to their excellent performance. In this work, high-quality and crack-free Yb3+:Lu3Al5O12 (Yb:LuAG) SCFs were successfully fabricated by the micro-pulling-down (μ-PD) technology. Based on the laser micrometer and the X-ray Laue diffraction results, these Yb:LuAG SCFs have a less than 5% diameter fluctuation and good crystallinity along the axial direction. More importantly, the distribution of Yb ions is proved to be uniform by electron probe microanalysis (EPMA) and the scanning electron microscope (SEM). In the laser experiment, the continuous-wave (CW) output power using a 1 mm diameter Yb:LuAG single-crystal fiber is determined to be 1.96 W, at the central wavelength of 1047 nm, corresponding to a slope efficiency of 13.55%. Meanwhile, by applying a 3 mm diameter Yb:LuAG SCF, we obtain a 4.7 W CW laser output at 1049 nm with the slope efficiency of 22.17%. The beam quality factor M2 is less than 1.1 in both conditions, indicating a good optical quality of the grown fiber. Our results show that the Yb:LuAG SCF is a potential solid-state laser gain medium for 1 μm high-power lasers.

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Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽

10.3390/en14102760 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2760

Author(s):

Ruiye Li ◽

Peng Cheng ◽

Hai Lan ◽

Weili Li ◽

David Gerada ◽

...

Keyword(s):

Finite Element ◽

Temperature Distribution ◽

Design Methodology ◽

Large Scale ◽

Synchronous Generator ◽

Axial Direction ◽

Scale Model ◽

Element Analysis ◽

Axial Temperature ◽

Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

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The first observation of 4D tomography measurement of plasma structures and fluctuations

Scientific Reports ◽

10.1038/s41598-021-83191-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Chanho Moon ◽

Kotaro Yamasaki ◽

Yoshihiko Nagashima ◽

Shigeru Inagaki ◽

Takeshi Ido ◽

...

Keyword(s):

Steady State ◽

Three Dimensional ◽

Axial Direction ◽

Axial Position ◽

Entire Cross Section ◽

Helicon Plasma ◽

Emission Profile ◽

Dimensional Measurement ◽

Tomography System ◽

Three Dimensional Measurement

AbstractA tomography system is installed as one of the diagnostics of new age to examine the three-dimensional characteristics of structure and dynamics including fluctuations of a linear magnetized helicon plasma. The system is composed of three sets of tomography components located at different axial positions. Each tomography component can measure the two-dimensional emission profile over the entire cross-section of plasma at different axial positions in a sufficient temporal scale to detect the fluctuations. The four-dimensional measurement including time and space successfully obtains the following three results that have never been found without three-dimensional measurement: (1) in the production phase, the plasma front propagates from the antenna toward the end plate with an ion acoustic velocity. (2) In the steady state, the plasma emission profile is inhomogeneous, and decreases along the axial direction in the presence of the azimuthal asymmetry. Furthermore, (3) in the steady state, the fluctuations should originate from a particular axial position located downward from the helicon antenna.

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