scholarly journals Experimental Results for the Rotordynamic Characteristics of Leakage Flows in Centrifugal Pumps

1994 ◽  
Vol 116 (1) ◽  
pp. 110-115 ◽  
Author(s):  
A. Guinzburg ◽  
C. E. Brennen ◽  
A. J. Acosta ◽  
T. K. Caughey
Keyword(s):  
Flow Rate ◽  
Tangential Force ◽  
Fluid Structure Interaction ◽  
Centrifugal Pumps ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Leakage Flows ◽  
Clearance Face ◽  
Rotordynamic Forces

In recent years, increasing attention has been given to fluid-structure interaction problems in turbomachines. The present research focuses on just one such fluid-structure interaction problem, namely, the role played by fluid forces in determining the rotordynamic stability and characteristics of a centrifugal pump. The emphasis of this study is to investigate the contributions to the rotordynamic forces from the discharge-to-suction leakage flows between the front shroud of the rotating impeller and the stationary pump casing. An experiment was designed to measure the rotordynamic shroud forces due to simulated leakage flows for different parameters such as flow rate, shroud clearance, face-seal clearance and eccentricity. The data demonstrate substantial rotordynamic effects and a destabilizing tangential force for small positive whirl frequency ratios; this force decreased with increasing flow rate. The rotordynamic forces appear to be inversely proportional to the clearance and change significantly with the flow rate. Two sets of data taken at different eccentricities yielded quite similar nondimensional rotordynamic forces indicating that the experiments lie within the linear regime of eccentricity.

scholarly journals The Effect of Inlet Swirl on the Rotordynamic Shroud Forces in a Centrifugal Pump

1992 ◽  
Author(s):  
A. Guinzburg ◽  
C. E. Brennen ◽  
A. J. Acosta ◽  
T. K. Caughey
Keyword(s):  
Centrifugal Pump ◽  
Guide Vane ◽  
Tangential Force ◽  
Inlet Guide Vane ◽  
Fluid Forces ◽  
Leakage Flows ◽  
Leakage Path ◽  
Inlet Swirl ◽  
Rotating Impeller ◽  
Rotordynamic Forces

The role played by fluid forces in determining the rotordynamic stability of a centrifugal pump is gaining increasing attention. The present research investigates the contributions to the rotordynamic forces from the discharge-to-suction leakage flows between the front shroud of the rotating impeller and the stationary pump casing. In particular, the dependency of the rotordynamic characteristics of leakage flows on the swirl at the inlet to the leakage path was examined. An inlet guide vane was designed for the experiment so that swirl could be introduced at the leakage flow inlet. The data demonstrates substantial rotordynamic effects and a destabilizing tangential force for small positive whirl ratios; this force decreased with increasing flow rate. The effect of swirl on the rotordynamic forces was found to be destabilizing.

A Qualified Method for Fluid-Structure Interaction in Piping Design

2006 ◽  
Author(s):  
Miks Hartmann
Keyword(s):  
Fluid Structure Interaction ◽  
Substantial Contribution ◽  
Structural Dynamic ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Various Boundary Conditions ◽  
Coupled Calculation ◽  
Piping Systems ◽  
Hydraulic Load

In piping design hydraulic load cases and the resulting dynamic structural loads are induced and generated by strongly time dependent pressure surges and subsequent oscillations. Therefore, with liquid filled piping, the implementation of fluid-structure interaction by coupling the fluiddynamic and the structural dynamic codes gives a substantial contribution to more realistic loading results. Considering this effect, usually a load reduction due to energy losses and the phase and frequency shift from fluid to structure and vice versa is achieved. In cases of fluid structure resonance the results are more reliable and can help to develop an optimized support concept. To realize the coupled calculation of both codes they are bundled by a special user environment, where the coupling points are specified and marked. We describe the input of fluid forces at those points and the treatment of the liquid masses inside the piping, as well as the method of back-coupling the resulting structural displacements into the fluid calculation. The method was validated against measurements of load cases in power plant piping systems and experimental results for various boundary conditions. The most realistic results were obtained by combining the coupling with the application of dynamic friction in the fluid code.

scholarly journals Optimization and Analysis of Centrifugal Pump considering Fluid-Structure Interaction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Zhang ◽  
Sanbao Hu ◽  
Yunqing Zhang ◽  
Liping Chen
Keyword(s):  
Centrifugal Pump ◽  
Fluid Structure Interaction ◽  
Kriging Model ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Transient Vibration ◽  
Pump Impeller ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Vibration Performance

This paper presents the optimization of vibrations of centrifugal pump considering fluid-structure interaction (FSI). A set of centrifugal pumps with various blade shapes were studied using FSI method, in order to investigate the transient vibration performance. The Kriging model, based on the results of the FSI simulations, was established to approximate the relationship between the geometrical parameters of pump impeller and the root mean square (RMS) values of the displacement response at the pump bearing block. Hence, multi-island genetic algorithm (MIGA) has been implemented to minimize the RMS value of the impeller displacement. A prototype of centrifugal pump has been manufactured and an experimental validation of the optimization results has been carried out. The comparison among results of Kriging surrogate model, FSI simulation, and experimental test showed a good consistency of the three approaches. Finally, the transient mechanical behavior of pump impeller has been investigated using FSI method based on the optimized geometry parameters of pump impeller.

Fluid-Structure Interaction With S-TRAC and KWUROHR Due to Pressure Waves

2003 ◽  
Author(s):  
Ulrich Neumann
Keyword(s):  
Fluid Structure Interaction ◽  
Dynamic Program ◽  
Pressure Waves ◽  
Structural Dynamic ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Piping Systems

In the last years we have spent a lot of time to improve our programs and procedures, especially on the field of fluiddynamic investigations in piping systems. To get the best design of piping layout the results of fluiddynamic and structural calculations should be realistic as far as possible. In this connection a very important effect is the fluid-structure interaction (FSI) which we have implemented in S-TRAC in connection with our structural dynamic program KWUROHR. On the basis of different calculations we will show the influence of the coupling on the fluid forces and the piping layout.

Torque Analysis of IPMC Actuated Fin of a Micro Fish like Device Using Two-Way Fluid Structure Interaction Approach

2015 ◽  
Vol 25 ◽  
pp. 25-38
Author(s):  
Mazhar Ul Haq ◽  
Zhao Gang ◽  
Zhuang Zhi Sun ◽  
S.M. Aftab
Keyword(s):  
Numerical Simulation ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Pressure Profile ◽  
Three Dimensional Model ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Flow Speeds ◽  
Interaction Approach

In this paper, a numerical simulation of three dimensional model of IPMC actuated fin of a fish like micro device is presented using two-way fluid structure interaction approach. The device is towed by the surface vessel through a tow cable. Fin is acting as dorsal fin of the fish to control depth of the device and also acts as a stabiliser against its roll motion. Fin's displacement disturbs water flow streamlines around it, as a result velocity and pressure profile of fluid's domain changes around the actuated fin. As fin's position continuously changes throughout its actuation cycle, this makes it transient structural problem coupled with a fluid domain. Fin's displacement is received by the fluid and resulting fluid forces are received by the fin making it a two-way fluid structure interaction (FSI) problem. Such problems are solved by multi field numerical simulation approach. This multifield numerical simulation is performed in ANSYS WORKBENCH by coupling transient structural and Fluid Flow (CFX) analysis systems. It is desirous to determine the torque acting on the fin due to fluid forces through its actuation cycle by IPMC actuators. The objective of this study is to develop the methodology (two-way fluid structural interaction (FSI)) used to simulate the transient FSI response of the IPMC actuated fin, subjected to large displacement against different flow speeds. Efficacy of fin as depressor and riser is also required to be judged by monitoring the forces acting on wing in response to its displacement under IPMC actuation. Same approach is also applicable to the self-propelled systems.

Numerical Evaluation of Deformation and Stress in Impellers of Multistage Pumps by Means of Fluid Structure Interaction

2013 ◽  
Author(s):  
Andreas Schneider ◽  
Björn-Christian Will ◽  
Martin Böhle
Keyword(s):  
Numerical Evaluation ◽  
Fluid Structure Interaction ◽  
Hydrodynamic Pressure ◽  
Operational Reliability ◽  
Operating Conditions ◽  
Design Parameters ◽  
Centrifugal Pumps ◽  
Fluid Structure ◽  
Structural Part ◽  
Structure Interaction

The operational reliability of centrifugal pumps strongly depends on an adequate structural design of every single component. Therefore, the design process requires trustworthy information about the expected stresses and deformations. The numerical evaluation of the deformations and the stresses in the impellers of multistage centrifugal pumps is the topic of this report. The loads acting on the impeller under operating conditions can be subdivided into structural and hydrodynamic components, which are considered by means of one-way coupled fluid-structure interaction (FSI) simulations. For the investigations, an exemplary multistage pump with a specific speed of nq = 30 has been chosen. The hydrodynamic pressure loads on the impeller are derived from the CFD solution for a single stage of the pump. These pressure loads are imposed on the impeller in the structural part of the simulation. In order to determine the resulting deformations and stresses of the impeller, static structural analyses are performed. Different operating conditions, i.e. flow rates and temperatures, are analyzed. Furthermore, the influence of structural impeller design parameters on the resulting deformations and stresses is investigated in detail. The thickness of the impeller shrouds as well as the fillet radii between the blades and the shrouds are considered as design parameters.

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.

scholarly journals Stochastic fluid structure interaction of three-dimensional plates facing a uniform flow

2016 ◽  
Vol 794 ◽  
Author(s):  
O. Cadot
Keyword(s):  
Fluid Structure Interaction ◽  
Angular Position ◽  
Three Dimensional ◽  
Uniform Flow ◽  
Steady States ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Long Time ◽  
Order Of Magnitude

An experiment on a flat rectangular plate facing a uniform flow at $Re=264\,000$ shows the importance of the base pressure loading on the asymmetric static modes of the turbulent wake. The plate is free to rotate around its short symmetry axis. For plates with aspect ratio ${\it\kappa}<6$, the angular position exhibits strong random discontinuities between steady states of non-zero angles. The steady states have long time durations, more than one order of magnitude greater than the convective time scale. The discontinuities, comparable to rare and violent events, are due to strong fluid forces associated with a drastic global change of the three-dimensional wake – mainly the switching between the static asymmetric modes. A clear transition occurs at ${\it\kappa}=6$, for which the angular fluctuations are minimum, leading for ${\it\kappa}>6$ to a classical fluid structure interaction with periodic fluctuations. The transition is supported by a recent global stability analysis of rectangular fixed plates in the laminar regime.

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