A Novel Axial Vibration Model of Multistage Pump Rotor System with Dynamic Force of Balance Disc

2019 ◽  
Vol 8 (5) ◽  
pp. 673-683
Author(s):  
Wenjie Zhou ◽  
Yuhua Cao ◽  
Ning Zhang ◽  
Bo Gao ◽  
Ning Qiu ◽  
...  
Keyword(s):  
Rotor System ◽  
Dynamic Force ◽  
Axial Vibration ◽  
Pump Rotor ◽  
Vibration Model ◽  
Multistage Pump

scholarly journals A coupling vibration model of multi-stage pump rotor system based on FEM

Mechanika ◽  
2016 ◽  
Vol 22 (1) ◽  
Author(s):  
Leqin Wang ◽  
Wenjie Zhou ◽  
Xuesong Wei ◽  
Lulu Zhai ◽  
Guangkuan Wu
Keyword(s):  
Rotor System ◽  
Coupling Vibration ◽  
Pump Rotor ◽  
Multi Stage ◽  
Vibration Model

Characteristics of Centrifugal Pump Rotor System Under Exciting Forces Generated by Shroud Leakage Flows

2010 ◽  
Author(s):  
Quan-zhong Liu ◽  
Ru-zhi Gong ◽  
Hong-jie Wang ◽  
Yang Yao
Keyword(s):  
Centrifugal Pump ◽  
Rotor System ◽  
Least Square ◽  
Force Model ◽  
Dynamic Force ◽  
Pump Rotor ◽  
Leakage Flows ◽  
Exciting Forces ◽  
Rotordynamic Forces ◽  
Turbo Pump

In order to investigate the flow-induced vibration in the impeller clearance of centrifugal pump, and make the rotordynamic prediction of the centrifugal pump rotor system, a rotordynamic force model is established which is indispensable to the impeller-rotor system dynamics analysis. The coefficient in the dynamic force model is solved by quasi-steady CFD solution. Multiple quasi-steady solutions of an eccentric three-dimensional model at a series of relative spin velocity yield the rotordynamic forces at different whirl frequency ratios, and a second-order least-square fitting of the rotordynamic forces generates the skew-symmetric stiffness, damping, and mass matrices. Based on the work, the finite element method is applied to establish the model of turbo pump impeller-rotor system. The phenomenon of the fluid oscillation and some typical features are explained from the perspective of oscillation fluid mechanics. The results show complicated frequency characteristics presents in the turbo pump rotor vibration due to the exciting forces generated by shroud leakage flows.

Static Structural Analysis of the Blood Pump Rotor System

2014 ◽  
Vol 533 ◽  
pp. 82-85
Author(s):  
Kang Sun ◽  
Jun Feng Wang ◽  
Xin Wu ◽  
Ji Ge ◽  
Zhong Yun
Keyword(s):  
Structural Characteristics ◽  
Axial Flow ◽  
Strain Analysis ◽  
Rotor System ◽  
Blood Pump ◽  
Pump Rotor ◽  
Axial Flow Blood Pump ◽  
Object Use ◽  
External Forces ◽  
The Impact

In order to study the impact of external forces of the influence of the structural characteristics of axial flow blood pump rotor system.Using the blood pump rotor system as the research object,use ANSYS software,Use the method of static structure.the stress and strain analysis nephogram of the blood pump rotor system was obtained under the external load.through the study: The deformation of the blood pump rotor system which under the action of external load was mainly concentrated in the external contact of blade wheel rotor and ceramic shaft,but the deformation is small.So the blood pump rotor system design is reasonable. The vulnerability part of the blood pump rotor system was obtained.it provide date support for the further optimization of the blood pump rotor system and it also lay the foundations for the subsequent dynamic analysis.

Calculating Cutoff Speeds of a Multistage Pump Rotor Taking into Account Lomakin Effect in the Front Seal of the Impeller

2020 ◽  
pp. 59-67
Author(s):  
D.G. Svoboda ◽  
A.A. Zharkovskii ◽  
E.A. Ivanov ◽  
I.O. Borshchev
Keyword(s):  
Hydrodynamic Forces ◽  
Centrifugal Pumps ◽  
Pump Rotor ◽  
Operating Modes ◽  
Flow Parameters ◽  
Ansys Cfx ◽  
Vibrational Characteristics ◽  
Shaft Deflection ◽  
Multistage Pump ◽  
Quantitative Impact

Studies of dynamic frequencies are an important stage in designing multistage vane pumps. This research aimed to confirm the rigidity and vibrational reliability of the pump rotor. Based on the recommendations of J.F. Gülich, the nominal rotational speed of the rotor shaft should differ from the cutoff speed by no less than 25 %. The Lomakin effect supposes taking into consideration the hydrodynamic forces acting in the gap seals and having a damping effect on the pump rotor. This research solved the problem of developing and verifying a numerical method of calculating hydrodynamic forces, which arise in seals of vane pumps at critical speeds. The studies were conducted on a ‘dry’ model of the rotor using ANSYS Mechanical software package. During computational modeling of bearings and seals, the COMBIT214 ele¬ment was used where the stiffness coefficient values were set. These values were determined by calculating the flow parameters in the gap seal using ANSYS CFX. The proposed method was verified using the experimental data obtained. The seal rigidity was calculated for different operating modes of the pump. It was shown that the hydrodynamic forces which arose in the gap seals had a significant influence on the rotor’s critical speed. Accounting for these forces increased the main own frequency of the rotor by approximately 44 %. This fact had a significant qualitative and quantitative impact on the vibrational characteristics of the pump. This study showed that the value of the hydrodynamic force was influenced by several factors: shaft deflection, differential pressure and geometry of the gap seal. The proposed method is recommended for use for multistage centrifugal pumps.

Dynamic Characteristics of Ball Bearing-Coupling-Rotor System with Angular Misalignment Fault

2021 ◽  
Author(s):  
Pengfei Wang ◽  
Hongyang Xu ◽  
Yang Yang ◽  
Hui Ma ◽  
Duo He ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Degrees Of Freedom ◽  
Ball Bearing ◽  
Element Model ◽  
Rolling Bearing ◽  
Rotor System ◽  
Radial Clearance ◽  
Axial Vibration ◽  
Restoring Force ◽  
Misalignment Fault

Abstract The rotor misalignment fault, which occurs only second to unbalance, easily occurs in the practical rotating machinery system. Rotor misalignment can be further divided into coupling misalignment and bearing misalignment. However, most of the existing references only analyze the effect of coupling misalignment on the dynamic characteristics of the rotor system, and ignore the change of bearing excitation caused by misalignment. Based on the above limitations, a five degrees of freedom nonlinear restoring force mathematical model is proposed, considering misalignment of bearing rings and clearance of cage pockets. The finite element model of the rotor is established based on the Timoshenko beam element theory. The coupling misalignment excitation force and rotor unbalance force are introduced. Finally, the dynamic model of the ball bearing-coupling-rotor system is established. The radial and axial vibration responses of the system under misalignment fault are analyzed by simulation. The results show that the bearing misalignment significantly influences the dynamic characteristics of the system in the low-speed range, so bearing misalignment should not be ignored in modeling. With the increase of rotating speed, rotor unbalance and coupling misalignment have a greater impact. Misalignment causes periodic changes in bearing contact angle, radial clearance, and ball rotational speed. It also leads to reciprocating impact and collision between the ball and cage. In addition, misalignment increases the critical speed and the axial vibration of the system. The results can provide a basis for health monitoring and misalignment fault diagnosis of the rolling bearing-rotor system.

Experimental and Numerical Analysis of Dynamics of the Rotor-Bearing-Seal System

2007 ◽  
Author(s):  
Xiaoyao Shen ◽  
Jianping Jing ◽  
Qimiao Gong
Keyword(s):  
Linear Equations ◽  
Experimental System ◽  
Rotor System ◽  
Force Model ◽  
Nonlinear Phenomena ◽  
Dynamic Force ◽  
Oil Film ◽  
Rotor Bearing ◽  
Linear And Nonlinear ◽  
Analysis Of Dynamics

Linear and nonlinear dynamics and stability of the rotor-bearing-seal system are investigated both theoretically and experimentally. First the system is modeled with the finite element method. The rotordynamic behavior of the journal bearing and the labyrinth seal are represented by eight linearized dynamic force coefficients. An experimental rotor-bearing-seal device is designed and tests are carried out. The experimental system is studied using the developed linear equations. Complex eigenvalues are solved. Corresponding critical speeds and logarithmic decrements to determine the thresholds of instability are calculated. Then the experimental rotor system is simplified as the Jeffcott rotor. The nonlinear oil-film forces are got under the short bearing theory and Muszynska nonlinear seal force model is used. Numerical method is utilized to solve the nonlinear governing equations. Bifurcation diagrams, Poincare´ maps, spectrum plots and rotor orbits are drawn to analyze various nonlinear phenomena and system unstable process. Theoretical results from the linear and nonlinear analysis are in good agreement with results from experiments. Conclusions are drawn and prove that this study will contribute to the further understanding of dynamics and stability of the rotor system with the fluid-induced forces from oil-film bearings and the seals.

scholarly journals Implementation of vibration and stability evaluation criteria for rotating machineries equipped with active magnetic bearings

2021 ◽  
Vol 13 (1) ◽  
pp. 168781402098734
Author(s):  
Kexiang Li ◽  
Cong Peng ◽  
Zhiquan Deng ◽  
Zhongming Zhang ◽  
Kaiwen Cai
Keyword(s):  
Controller Design ◽  
Evaluation Criteria ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Single Input Single Output ◽  
Single Output ◽  
Vibration Model ◽  
Rotor Balance ◽  
Rotating Machineries

Imbalance vibration is the main factor affecting the stability of rotating machineries equipped with active magnetic bearings (AMB). Accordingly, for safe and reliable operation, ISO 14839 standard sets out guidelines for measuring and evaluating the vibration and stability. However, technical approaches to realize fulfillment of the evaluation criteria have never been studied in theory. This paper presents insights of these criteria and proposes effective methods to simultaneously implement these evaluation criteria. Based on imbalance vibration model of AMB-rotor system, the theoretical connections between these evaluation indices are revealed. In order to obtain accurate vibration model of single-input single-output (SISO) AMB-rotor system, modal analysis is carried out and equivalent mass of SISO system is figured out. Afterwards, with the analysis of sensitivity function in theory, new indices of the evaluation criteria are proposed, which helps establish requirements of controller design and rotor balance quality. Finally, through experimental verification on a test rig, the limitations on the evaluation criteria can be negligible, and the proposed methods to simultaneously implement the evaluation criteria are validated.

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