Vibrations: Noises Produced by Rotors and Eddy Current Probes

1997 ◽  
Author(s):  
The Tam Nguyen ◽  
Roland Bigret
Keyword(s):  
Noise Suppression ◽  
Diagnostic System ◽  
Magnetic Bearing ◽  
Synchronous Mode ◽  
Machine Reliability ◽  
General Rules ◽  
Validation Procedure ◽  
Modern Manufacturing ◽  
Manufacturing Techniques ◽  
Bearing Structure

Abstract • The rotating equipment monitoring, protection and diagnostic system is based mainly on the knowledge of bearing structure vibrations and shaft relative vibrations. The vibration measurements are performed respectively by seismic transducers and proximity probe transducers. • Measured signals are affected by uncertainties, the most significant sources of which could be mechanical and electrical runout. • These uncertainties are mentioned by well known standards which recommend or dictate general rules but do not give any advice or procedure in view of reaching the main objective, that is to optimize the efficiency of the monitoring, protection and diagnostic system to improve machine reliability. • This paper gives two examples showing the effect of inaccuracies, due to noise, on the interpretation of the machine vibrations. • One validation procedure identifying true noise will be given, using the rotor slow roll principle. • Noise suppression will be presented requiring sampling and resampling of time domain signals taken on a non synchronous mode. A newly designed software will be used. • Mechanical runout could induce inacurracies on rotors low speed balancing. • Noises could create harmful forces on the rotor in a magnetic bearing system. • Modern manufacturing techniques can minimize mechanical runout in order to avoid noise suppression which could generate additional incaccuracies.

scholarly journals Analytical Modeling and Simulation of S-Drive Piezoelectric Actuators

Actuators ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 87
Author(s):  
Nicholas A. Jones ◽  
Jason Clark
Keyword(s):  
Element Model ◽  
Mechanical Efficiency ◽  
Compact Model ◽  
High Frequency Response ◽  
Macro Scale ◽  
Piezoelectric Structure ◽  
Modern Manufacturing ◽  
Manufacturing Techniques ◽  
Piezoelectric Structures ◽  
Improve Device

This paper presents a structural geometry for increasing piezoelectric deformation, which is suitable for both micro- and macro-scale applications. New and versatile microstructure geometries for actuators can improve device performance, and piezoelectric designs benefit from a high-frequency response, power density, and efficiency, making them a viable choice for a variety of applications. Previous works have presented piezoelectric structures capable of this amplification, but few are well-suited to planar manufacturing. In addition to this manufacturing difficulty, a large number of designs cannot be chained into longer elements, preventing them from operating at the macro-scale. By optimizing for both modern manufacturing techniques and composability, this structure excels as an option for a variety of macro- and micro-applications. This paper presents an analytical compact model of a novel dual-bimorph piezoelectric structure, and shows that this compact model is within 2% of a computer-distributed element model. Furthermore it compares the actuator’s theoretical performance to that of a modern actuator, showing that this actuator trades mechanical efficiency for compactness and weight savings.

Pore design and engineering for filters and membranes

2005 ◽  
Vol 364 (1838) ◽  
pp. 161-174 ◽  
Author(s):  
Richard Holdich ◽  
Serguei Kosvintsev ◽  
Iain Cumming ◽  
Sergey Zhdanov
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Pore Size ◽  
Suspended Material ◽  
Slot Length ◽  
Depth Filtration ◽  
Flow Through ◽  
Pore Flow ◽  
Modern Manufacturing ◽  
Manufacturing Techniques

In filtration, the concept of pore size is not easy to define. In microfiltration, there are numerous advantages in employing a surface filtering membrane, rather than one relying on depth filtration mechanisms from a tortuous pore flow channel. Modern manufacturing techniques provide means to produce surface filtering membranes. For filtration, it is shown that a suitable pore design is an array of long thin slots. An analysis of fluid flow through the slots suggests that a short slot is adequate, but experimental data with suspended material indicates that slot length is important. Using long slots and careful control of the flow through the membrane it is possible to filter deforming particles such as oil drops from water.

Monitoring and Diagnostics of the Rotating System with an Active Magnetic Bearing

2013 ◽  
Vol 198 ◽  
pp. 547-552
Author(s):  
Małgorzata Gizelska ◽  
Dorota Kozanecka ◽  
Zbigniew Kozanecki
Keyword(s):  
Diagnostic System ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Rotating System ◽  
Automatic Mode ◽  
Actual Operation ◽  
Advanced Information Technology ◽  
Monitoring And Diagnostics ◽  
Proper Operation

In the paper, a concept and selected procedures of the specialized software using advanced information technology for the diagnostic system dedicated for systems of rotating machines with active magnetic bearings will be presented. It is used in the actual operation of the machine, enabling an increase of its reliability. The paper presents some selected results of control of the proper operation of the mechatronic rotating system, carried out in the automatic mode.

scholarly journals Design Optimization of Permanent Magnet Clutch with Ārtap Framework

2021 ◽  
Vol 65 (2) ◽  
pp. 106-112
Author(s):  
Ekaterina Andriushchenko ◽  
Jan Kaska ◽  
Ants Kallaste ◽  
Anouar Belahcen ◽  
Toomas Vaimann ◽  
...  
Keyword(s):  
Design Optimization ◽  
Permanent Magnet ◽  
Attraction Force ◽  
Effective Utilization ◽  
Linear Dimensions ◽  
Optimal Shapes ◽  
Torque Transmission ◽  
Optimization Parameters ◽  
Modern Manufacturing ◽  
Manufacturing Techniques

So far, Permanent Magnet (PM) clutches have been broadly used as torque transmission devices. With the aim of effective utilization of materials and energy in the manufacturing of PM clutches, design optimization has been widely applied. Generally, PM clutches are optimized applying linear dimensions as optimization parameters. On the contrary, optimization of PM clutch shapes has not been done extensively. Therefore, this paper performs optimization of PM clutch shapes with the following objectives: maximum tangential attraction force and minimum volume of utilized materials. To form optimal shapes, the points on the clutch surface are chosen as optimization parameters. The optimization is carried out using Ārtap framework in connection with COMSOL software, where the 3D model of the clutch has been created. After the optimization, the tangential attraction force has increased by 13 % and the volume of the clutch has been reduced by 24 %. Although the obtained shapes appear to be highly intricate, it does not pose an obstacle for modern manufacturing techniques.

Rotor Wake Variability in a Transonic Compressor Stage

2004 ◽  
Author(s):  
Nicole L. Key ◽  
Patrick B. Lawless ◽  
Sanford Fleeter
Keyword(s):  
Rotor Blades ◽  
Turbine Engines ◽  
Wake Structure ◽  
Piv Measurements ◽  
Transonic Compressor ◽  
Image Velocimetry ◽  
Forcing Functions ◽  
Modern Manufacturing ◽  
Manufacturing Techniques ◽  
The Individual

High Cycle Fatigue (HCF) is a fundamental weakness in the technology base for turbine engines. Modern compressor designs feature closely spaced blade rows of low aspect ratio increasing the strength and complexity of aerodynamic forcing functions. Also, modern manufacturing techniques produce blisks with low levels of mechanical damping. Thus, classic simplified views of the forcing functions may no longer be sufficient to accurately predict blade response. The concept of the “average wake” and the role that deviations from this average, or wake variability, plays as an HCF driver become important. Experiments are performed in the Purdue Transonic Research Compressor where two different but geometrically similar rotor blades from the same blisk are investigated; one that produces a near nominal wake and another that demonstrates significant variability according to thermal anemometry measurements. The Particle Image Velocimetry (PIV) measurements provide both phase-locked and instantaneous views of the wake structure showing variability in the individual wake structure.

Research on Auxiliary Bearing Structure With Buffer Shim Based on LS-DYNA for Helium Circulator of HTR-10

2018 ◽  
Author(s):  
Guojun Yang ◽  
Zhe Sun ◽  
Xingnan Liu ◽  
Zhengang Shi
Keyword(s):  
Stress Distribution ◽  
Impact Load ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Structure Characteristic ◽  
System A ◽  
Huge Impact ◽  
Auxiliary Bearing ◽  
The Impact ◽  
Bearing Structure

The active magnetic bearing (AMB) is introduced to the helium circulator of the 10 MW high temperature gas-cooled reactor (HTR-10). Auxiliary bearing bears huge instantaneous impact load when the AMB fails to work in the helium circulator. The huge load may cause serious damage to the auxiliary bearing. In order to reduce the impact load and protect the AMB and rotor system, a new type of auxiliary bearing with axial buffer shim is presented in this paper. There are two different structures of auxiliary bearing to be studied in the paper. One is the auxiliary bearing with the buffer shim and another one is without the buffer shim. The finite element method and LS-DYNA software are applied to analyze the structure characteristic of the auxiliary bearing. The rotor dropping trajectory and the stress distribution of the auxiliary bearing are analyzed by comparing two different auxiliary bearing structures during the rotor drop. The stress change of the auxiliary bearing in each impact course is mainly studied, and the law of stress variation in impact course is analyzed. Besides, the stress distribution and deformation of two auxiliary bearing is the focus research when impact force is maximum in the paper. Finally, the research shows the auxiliary bearing structure without the buffer shim can bear the huge impact of the rotor drop, and the addition of buffer shim can also reduce the damage of the rotor drop to the auxiliary bearing structure. These researches’ result provides an important reference for the experiment of rotor drop, and has laid a theoretical foundation for the practical application of this structure.

Introduction to Modern Manufacturing Techniques

2021 ◽  
pp. 1-46
Author(s):  
Jitendra Kumar Katiyar ◽  
Ranjeet Kumar Sahu
Keyword(s):  
Modern Manufacturing ◽  
Manufacturing Techniques
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