Two-Way Coupling Fluid–Structure Interaction Analysis and Tests of Shaft Vibration and Clearance Flow Across Plain Annular Seal

2019 ◽  
Vol 86 (10) ◽  
Author(s):  
Kenjiro Miyake ◽  
Tsuyoshi Inoue ◽  
Yusuke Watanabe
Keyword(s):  
Continuity Equation ◽  
Fluid Structure Interaction ◽  
Rotor System ◽  
Design Stage ◽  
Coupling Analysis ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Annular Seal ◽  
Clearance Flow ◽  
Shaft Vibration

Shaft vibration caused by rotor dynamic (RD) fluid force generated by the seal clearance flow has caused several problems. Because such vibration is a coupled phenomenon of clearance flow and shaft vibration, a coupling analysis is essential to solve these problems. In this study, a two-way coupling fluid–structure interaction (FSI) analysis of the seal clearance flow and shaft vibration of a rotor system was conducted and verified through experiments. The rotor system used was a vertical, flexible rotor system with a plain annular seal. In the numerical analysis of the seal clearance flow, the continuity equation and momentum equations, which were averaged across the film thickness, were numerically solved. To suppress the numerical instability, which is unique to the coupling analysis, and improve its numerical stability, a method of successively correcting pressure and shaft acceleration values was adopted so that the continuity equation and rotor equations of motion could be satisfied at every time step. By performing the coupling simulation, the frequency response characteristics of whirling amplitude and leakage flow were investigated. In regard to the stability of the system, the rotational speeds at which self-excited vibration occurs (onset speed of instability: OSI) in its increasing condition and ceases (onset speed of dropdown: OSD) in its decreasing condition were investigated. The coupling analysis results reasonably agree with the experimental results, which demonstrate the validity of the analysis method. In addition, the influence of static eccentricity and whirling amplitude on stability (OSI and OSD) was clarified, which are useful in the design stage of turbomachinery.

scholarly journals Fluid-Structure Interaction Analysis on Turbulent Annular Seals of Centrifugal Pumps during Transient Process

2011 ◽  
Vol 2011 ◽  
pp. 1-22 ◽  
Author(s):  
Qinglei Jiang ◽  
Lulu Zhai ◽  
Leqin Wang ◽  
Dazhuan Wu
Keyword(s):  
Transient Process ◽  
Transient Response ◽  
Fluid Structure Interaction ◽  
Rotor System ◽  
Centrifugal Pumps ◽  
Time Step ◽  
Fluid Structure ◽  
Rotor Systems ◽  
Structure Interaction ◽  
Annular Seal

The current paper studies the influence of annular seal flow on the transient response of centrifugal pump rotors during the start-up period. A single rotor system and three states of annular seal flow were modeled. These models were solved using numerical integration and finite difference methods. A fluid-structure interaction method was developed. In each time step one of the three annular seal models was chosen to simulate the annular seal flow according to the state of rotor systems. The objective was to obtain a transient response of rotor systems under the influence of fluid-induced forces generated by annular seal flow. This method overcomes some shortcomings of the traditional FSI method by improving the data transfer process between two domains. Calculated results were in good agreement with the experimental results. The annular seal was shown to have a supportive effect on rotor systems. Furthermore, decreasing the seal clearance would enhance this supportive effect. In the transient process, vibration amplitude and critical speed largely changed when the acceleration of the rotor system increased.

Numerical Study on Fluid Structure Interaction of Slug Flow in a Horizontal Pipeline

2016 ◽  
Vol 819 ◽  
pp. 319-325
Author(s):  
Abdalellah Omer Mohmmed ◽  
Mohammad Shakir Nasif ◽  
Hussain Hamoud Al-Kayiem ◽  
Zahid Ibrahim Al-Hashimy
Keyword(s):  
Slug Flow ◽  
Maximum Stress ◽  
Numerical Study ◽  
Fluid Dynamic ◽  
Fluid Structure Interaction ◽  
Water Velocity ◽  
Design Stage ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Model Code

It is well-known that when slug flow occurs in pipes it may result in damaging the pipe line. Therefore it is important to predict the slug occurrence and its effect. Slug flow regime is unsteady in nature and the pipelines conveying it are indeed susceptible to significant cyclic stresses. In this work, a numerical study has been conducted to investigate the interaction between the slug flow and solid pipe. Fluid Structure Interaction (FSI) coupling between 3-D Computational Fluid Dynamic (CFD) and 3-D pipeline model code has been developed to assess the stresses on the pipe due to slug flow. Time – dependent stresses results has been analyzed together with the slug characteristic along the pipe. Results revealed that the dynamic behavior of the pipelines is strongly affected by slug parameters. The FSI simulation results show that the maximum stresses occurred close to the pipe supports due to slug flow, where the pipe response to the exerted slug forces is extremely high. These stresses will subsequently cause fatigue damage which is likely reduce the total lifetime of the pipeline. Therefore a careful attention should be made during the design stage of the pipeline to account for these stresses. The system has been investigated under multiple water velocities and constant air velocity, the maximum stress was obtained at the water velocity of 0.505 m/s. Moreover, when the water velocity is increased from 0.502 to 1.003 m/s the maximum stress magnitude is decreased by 1.2% and when it is increased to 1.505 m/s the maximum stress is diminished by 3.6%.

Analysis of Coupled Water Hammer Vibration Equation of Improvement

2014 ◽  
Vol 926-930 ◽  
pp. 2986-2991
Author(s):  
Jian Bing Zhu ◽  
Zhi Min Su ◽  
Zhi Fang Tian ◽  
Xue Lu ◽  
Cheng Jie Jiang
Keyword(s):  
Continuity Equation ◽  
Fluid Structure Interaction ◽  
Water Hammer ◽  
Coupling Vibration ◽  
Fluid Structure ◽  
Vibration Equation ◽  
Structure Interaction ◽  
Continuity Equations

This paper further analyzes some existent problems of coupling vibration equations of water hammer, based on the improved continuity equation, it is derived simply for calculating coupled water hammer vibration, comparison with continuity equation that is to be used widely, the new continuity equation is basically consistent with commonly used continuity equations, so, the improved continuity equation can be used to calculate water hammer based on fluid-structure interaction (FSI).

Modelling of Hydrodynamic Forces on a Whirling Mixing Vessel Stirrer Including Fluid-Structure Interaction

2009 ◽  
Author(s):  
Khaled M. Mohamed ◽  
Andrew G. Gerber ◽  
Gordon A. L. Holloway
Keyword(s):  
Fluid Structure Interaction ◽  
Time Integration ◽  
Rotor System ◽  
Implicit Time ◽  
Arbitrary Lagrangian Eulerian ◽  
Governing Equations ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Rotordynamic Coefficients ◽  
Reported Data

In this paper, a modeling approach for strongly coupled Fluid-Structure Interaction (FSI) simulations of a mixing vessel stirrer is presented and discussed. A finite-volume Computational Fluid Dynamics (CFD) model is used to calculate the mixer flow field while the structural dynamics of the stirrer is based on a 2-DOF damped spring-mass oscillator system. The time integration of the stirrer response is carried out using the Newmark method, and is applied in conjunction with the implicit time integration of the fluid governing equations. The solution methodology employs a transient rotorstator interface to handle frame change between the rotor system and the baffles. Furthermore, mesh adaption around the rotor system is applied using an Arbitrary Lagrangian Eulerian (ALE) treatment of the fluid governing equations. The fluid forces acting on the impeller are analyzed and a method is proposed for extracting the added mass, damping, and stiffness coefficients, which are of significance in rotordynamic analysis. The computational results for the average stirrer deflections are in close agreement with experimental data, and the trends in the extracted rotordynamic coefficients align with other previously reported data for turbomachinery.

scholarly journals Prediction of flow induced vibrations in vertical turbine pumps using one-way fluid-structure interaction

2018 ◽  
Vol 211 ◽  
pp. 16002
Author(s):  
Ravindra Birajdar ◽  
Appasaheb Keste
Keyword(s):  
Test Data ◽  
Fluid Structure Interaction ◽  
Computational Effort ◽  
Design Stage ◽  
Centrifugal Pumps ◽  
Process Industries ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Turbine Pump ◽  
Major Factors

Centrifugal pumps/vertical turbine pumps are important and critical equipment for operation in the power generation, water supply, process industries and petrochemical industries. All centrifugal and vertical turbine pumps have rotors and structures that can vibrate in response to excitation forces. Mechanical and hydraulic unbalance are the two major factors which can create dynamic effects in terms of pump vibrations. In many cases the resulting hydraulic forces due to hydraulic unbalance has much the same effect as the mechanical unbalance. The vibrations in the pumps must be within acceptable limits of applicable standards. If there is higher level of vibrations, it not only leads to operational inefficiencies but also causes pump failures. Hence, it is very important for designers to understand the dominating fact of unbalance force and its origin. The prediction of vibrations in a vertical turbine pump due to the hydro dynamic forces, using numerical methods can help a designer to accomplish a successful design. The interaction between solid and fluid in present case can be completed by one-way coupling method. The one-way fluid-structure interaction approach is presented in present paper to predict the vibrations at specific operating condition which has good correlation with the test data. The advantage of reduced computational effort in this approach can be utilized during initial design stage. In this paper, a case study of one-way FSI approach of a vertical turbine pump is discussed. After detailed explanation about the CFD results, one-way coupling approach is explained with comparison of vibration displacements in both numerical and test data.

Application of Fluid-Structure Interaction Technique for Underwater Explosion Analysis of a Submarine Liquefied Oxygen Tank Considering Survivability

2008 ◽  
Author(s):  
Jae-Hyun Kim ◽  
Byung-Young Jeon ◽  
Jae-Hwang Jeon
Keyword(s):  
Structural Damage ◽  
Equations Of State ◽  
Fluid Structure Interaction ◽  
Underwater Explosion ◽  
Simple Calculation ◽  
Design Stage ◽  
Arbitrary Lagrangian Eulerian ◽  
Interaction Technique ◽  
Fluid Structure ◽  
Structure Interaction

The design of submarines has continually developed to improve survivability. Explosions may induce local damage as well as global collapse to a submarine structure. Therefore, it is important to realistically estimate the possible damage conditions due to underwater explosions in the design stage. In the present study, the Arbitrary Lagrangian-Eulerian (ALE) technique, a fluid–structure interaction approach is applied to simulate an underwater explosion and investigation of the survival capability of a damaged submarine with clamped liquefied oxygen tank. The Lagrangian-Eulerian coupling algorithm, the equations of state for explosives and seawater, and the simple calculation method for explosive loading were also reviewed. It is shown that underwater explosion analysis using the ALE technique can reasonably evaluate the structural damage caused by explosive load.

Sign in / Sign up

Export Citation Format

Share Document