Shafting Vibration Simulation for Hydro Turbine Generating Sets

2013 ◽  
Vol 444-445 ◽  
pp. 1171-1176
Author(s):  
Yun Zeng ◽  
Li Xiang Zhang ◽  
Jing Qian ◽  
Cheng Li Zhang
Keyword(s):  
Vibration Amplitude ◽  
Angular Speed ◽  
Transient Model ◽  
Integrated Simulation ◽  
Hydro Turbine ◽  
Equivalent Damping ◽  
Generating Sets ◽  
Mass Eccentricity ◽  
Equivalent Damping Coefficient ◽  
Vibration Simulation

Based on the transient model of hydro turbine generating sets (HTGS), the integrated simulation system of HGTS is built to study shafting stability. Given different bearing stiffness, equivalent damping coefficient and mass eccentricity, the change characteristics of shafting vibration at rated angular speed in steady and maximum angular speed in transient are simulated, and which are applied to study inferences shafting parameters and angular speed on shafting vibration. Simulation results show that the relationship between shafting vibration amplitude and angular speed is linear. however, the vibration amplitude increment produced by angular speed error will be amplified while the shafting stiffness is weaker, mass eccentricity of the runner and rotor is larger.

Extraction Shafting Oscillation Characteristic of Hydro Turbine Generating Sets Based on Prony Algorithm

2014 ◽  
Vol 889-890 ◽  
pp. 563-568
Author(s):  
Zhe Wu ◽  
Yun Zeng ◽  
Yan Yan Zeng ◽  
Shi Ge Yu
Keyword(s):  
Optimization Design ◽  
Attenuation Factor ◽  
Vibration Signal ◽  
Simulation Method ◽  
Structure Design ◽  
Operating Conditions ◽  
Transient Model ◽  
Hydro Turbine ◽  
Generating Sets ◽  
Prony Algorithm

Hydro turbine generating sets vibration is an important factor affecting the safe operation of hydropower stations. The research on the vibration characteristics is basic for the unit structure design, control design and hydropower station powerhouse structure optimization design. Based on built transient model of the hydropower turbine generating sets shafting, this paper constructed the whole hydropower turbine generating sets operating system by combine the hydro turbine, the generator object model, the governor and the excitation controller. Using numerical simulation method to obtained the shafting vibration data under different operating conditions. And then used Prony algorithm to extract the oscillation characteristics of amplitude, frequency, attenuation factor and phase angle from the vibration signal of hydro turbine generating sets shafting parameters. The simulation results show that the proposed method is effective.

Impact of the Unbalanced Magnetic Pull on the Shafting Vibration of Hydro Turbine Generating Sets

2014 ◽  
Vol 644-650 ◽  
pp. 406-411
Author(s):  
Yan Yan Zeng ◽  
Yun Zeng ◽  
Zhe Wu ◽  
Shi Ge Yu
Keyword(s):  
Hydraulic Turbine ◽  
Good Method ◽  
Transient Model ◽  
Hydro Turbine ◽  
Unbalanced Magnetic Pull ◽  
Generating Sets ◽  
Governing System ◽  
Prony Algorithm ◽  
Actual Operation ◽  
Different Characteristics

The unbalanced magnetic pull (UMP) of hydro turbine generating sets (HTGS) is one of the main reason induced vibration of the HTGS and the power plant. To study the effects of UMP on the shaft vibration characteristics of HTGS, this article constructs whole HTGS system which include hydraulic turbine and its hydraulic system, generator, transient model of the HTGS shafting, excitation and governing system, to simulate the actual operation of HTGS. The shafting vibration is simulated under different characteristics of UMP, simulation shows that the frequency resonance zone of the UMP has large influence on the shafting vibration. And then, the improved Prony algorithm is applied to extract the shafting oscillation characteristics of HTGS, and is effective. It provides a good method to research the effect of frequency and amplitude changes of UMP on the shafting vibration.

The Calculation of the Equivalent Linear Damping Coefficient of the Magnetorheological Damper

2013 ◽  
Vol 336-338 ◽  
pp. 475-479 ◽  
Author(s):  
Yao Hui Guo ◽  
En Wei Chen ◽  
Qun Wu ◽  
Yi Min Lu ◽  
Zeng Qiang Xia
Keyword(s):  
Mr Damper ◽  
Magnetorheological Damper ◽  
Damping Coefficient ◽  
Control Voltage ◽  
Characteristic Analysis ◽  
Equivalent Damping ◽  
Equivalent Linear ◽  
Linear Damping ◽  
Damper Control ◽  
Equivalent Damping Coefficient

MR damper (magnetorheological damper) has broad application prospects, and equivalent damping coefficient is very important of its dynamic characteristic analysis. Based on the modified Bouc_Wen model, the performance of MR damper was analyzed and the equivalent linear damping coefficient of MR damper was calculated. Based on simulation date of the modified Bouc_Wen model, the relationships between the equivalent linear damping coefficient of MR damper and the parameters of control voltage and MR dampers movement amplitude were established by the curve fitting regression analysis method. Verification results prove that the equivalent linear damping coefficient model has higher accuracy. For the vibration systems using strongly nonlinear MR damper, new model can effectively improve the efficiency of calculating the vibration analysis and the stability of the system in a certain frequency. At the same time, the model provides a theoretical basis for the application of MR damper control.

EVALUATIONS OF CLUSTER STRUCTURE AND MAGNETO-RHEOLOGY OF MR SUSPENSIONS

2005 ◽  
Vol 19 (07n09) ◽  
pp. 1437-1442 ◽  
Author(s):  
HIDEYA NISHIYAMA ◽  
KAZUNARI KATAGIRI ◽  
KATSUHISA HAMADA ◽  
KAZUTO KIKUCHI ◽  
KATSUHIKO HATA ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Cluster Formation ◽  
Cluster Structure ◽  
Mr Damper ◽  
Magnetic Flux Density ◽  
Equivalent Damping ◽  
Damping Characteristics ◽  
Mr Fluids ◽  
Equivalent Damping Coefficient ◽  
Particle Shapes

In the present study, we sysnthesize two types of MR fluids with different particle shapes and sizes. The magnetic functions are evaluated circulatingly by the analysis of cluster formation, rheological properties in the applied magnetic field and damping characteristics in the MR damper, comparing with those of commercial MR fluids. Final objective is to provide the fundamental data for the development of newly advanced MR fluids. The main topics consist of geographycal cluster formation depending on particle shapes and sizes, relating to the apparent viscosity and yield stress with magnetic flux density and further equivalent damping coefficient of two newly sysnthesised MR fluids comparing with those of LORD MR fluid.

Fabrication and characterization of highly controllable magnetorheological material in compression mode

2020 ◽  
Vol 31 (14) ◽  
pp. 1641-1661 ◽  
Author(s):  
Amin Fereidooni ◽  
Afonso Martins ◽  
Viresh Wickramasinghe ◽  
Afzal Suleman
Keyword(s):  
Magnetic Fields ◽  
Loss Factor ◽  
Magnetorheological Fluid ◽  
Loading Frequency ◽  
Magnetorheological Elastomer ◽  
Magnetorheological Elastomers ◽  
Equivalent Damping ◽  
Magnetorheological Effect ◽  
Equivalent Damping Coefficient

This article is focused on the development and characterization of highly controllable magnetorheological materials for stiffness and damping control in semi-active control applications. Two types of magnetorheological materials are developed in-house: magnetorheological elastomer with soft base elastomer, and magnetorheological fluid encapsulated in regular elastomer, namely magnetorheological fluid-elastomer. In both cases of magnetorheological elastomers and magnetorheological fluid-elastomers, the samples are evaluated using in-house-developed shear and compression test rigs, which are equipped with electromagnets and Hall effect sensors for measuring the magnetic field. These features provide the capability to precisely control a wide range of magnetic fields during the experiments. In the case of magnetorheological elastomers, the experimental results of the in-house magnetorheological elastomers are compared with commercially available counterparts made of hard base elastomer. It is shown that the controllability of the material, that is, the relative magnetorheological effect, is significantly improved in the case of magnetorheological elastomer with soft base elastomer. In addition to various magnetic fields, the samples are subjected to a range of loading amplitudes and frequencies. A general trend is observed where the frequency and strain amplitude cause an opposite effect on both the shear and compressive moduli: the increase in frequency gives rise to a higher value of modulus whereas the increase in amplitude reduces the modulus. Furthermore, the effect of bonding on the performance of the magnetorheological elastomers in compression mode is evaluated and the results indicate a significant increase in the modulus and decrease in the loss factor. In all the cases, however, the change of loss factor does not exhibit a predictable trend as a function of magnetic fields. In order to investigate a magnetorheological-based solution for controlling the damping of a semi-active system, magnetorheological fluid-elastomer samples are made in-house. These samples are fabricated using three different iron concentrations, and are tested in compression (squeeze) mode. The results of these experiments confirm that the equivalent damping coefficient of the material rises with the increase in magnetic field, and this effect becomes stronger as the iron concentration of magnetorheological fluids increases. It is also demonstrated that the magnetorheological effect is highly dependent on the loading frequency and amplitude, where the equivalent damping coefficient decreases with the increase in loading frequency and amplitude. In all the aforementioned cases, the stiffness of magnetorheological fluid-elastomers exhibits minor changes, which offers the in-house-developed magnetorheological fluid-elastomers as a damping only control option, a development that is different from the magnetorheological fluid-elastomers reported in the literature.

A new type of damper combining eddy current damping with rack and gear

2020 ◽  
pp. 107754632093711
Author(s):  
Yafeng Li ◽  
Shouying Li ◽  
Jianzhong Wang ◽  
Zhengqing Chen
Keyword(s):  
Eddy Current ◽  
Permanent Magnets ◽  
Air Gap ◽  
Damping Coefficient ◽  
Apparent Mass ◽  
Damping Force ◽  
Equivalent Damping ◽  
Eddy Current Damping ◽  
New Type ◽  
Equivalent Damping Coefficient

A new type of damper combining eddy current damping with rack and gear, which can simultaneously export damping and inertial forces, is proposed. Eddy current damping with rack and gear is supposed to be installed between the building superstructure and foundation to mitigate the seismic response of the building. First, the concept of eddy current damping with rack and gear is introduced in detail and its apparent mass and equivalent damping coefficient are both theoretically investigated. Second, a prototype of eddy current damping with rack and gear is manufactured, and a series of tests on the prototype are carried out to verify its structural parameters. The experimental and theoretical results of the apparent mass of the prototype agree well with each other. The experimental result of the equivalent damping coefficient of the prototype is slightly lower than the numerical results obtained from COMSOL Multiphysics and its maximum relative differences are 11.3% and 13.6% for α = 0° and 45°, respectively. Third, detailed parametric studies on the damping force, including the effects of the thickness of the conductor plate, air gap, and number and location of permanent magnets, are conducted. The results show that the damping force keeps a linear relationship with velocity if it is lower than 0.15 m/s, and with the increase of the velocity, a strong nonlinear relationship between the damping force and the velocity is observed. The available maximum damping force can be increased by decreasing the thickness of the conductor plate and the air gap, increasing the number of permanent magnets. There is an optimal location about the permanent magnets for the available maximum damping force. In addition, the hysteretic curves of the eddy current damping with rack and gear obtained from the test indicate that the ability of energy dissipation is considerable.

Dynamic investigation of a spatial multi-body mechanism considering joint clearance and friction based on coordinate partitioning method

2021 ◽  
pp. 095440622110255
Author(s):  
Gao Hua ◽  
Zhai Jingyu ◽  
Zhang Hao ◽  
Han Qingkai ◽  
Liu Jinguo
Keyword(s):  
Lagrange Equation ◽  
Contact Point ◽  
Stable State ◽  
Constraint Equation ◽  
Friction Model ◽  
Dynamic Equations ◽  
Joint Clearance ◽  
Equivalent Damping ◽  
Equivalent Damping Coefficient ◽  
Coordinate Partitioning

The dynamic response of the model, which is the series connection of a planar four-bar mechanism and a spatial RSSR mechanism, is analyzed considering revolute joint clearance and friction. A non-holonomic constraint equation is proposed to solve the Euler angles. The dynamic equations are established by combining the Lagrange equation with the modified contact model and the LuGre friction model. A dynamic solution program based on the coordinate partitioning method is designed to solve the dynamic equations. The paper verifies the correctness and applicability of the solution program by comparing the numerical calculation results with Adams simulation. Compared with the results of eccentricity, it is found that the maximum penetration is very sensitive to the change of the slider speed rather than the clearance. The equivalent damping coefficient proposed by authors not only represents whether a collision occurs, but reflects the hysteresis caused by damping. The macroscopic manifestation of the up and down oscillation of eccentricity is the swing of the contact point. Besides, the system quickly changes from the collision into the stable state due to considering friction, and the peak value of each collision reduces greatly. Therefore, when the clearance is unavoidable, the clearance joint should be coated with a material with a large friction coefficient and not easy to wear.

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