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.

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.

Optimization of Loads in Piping Systems by the Realistic Calculation Method Applying Fluid-Structure-Interaction (FSI) and Dynamic Friction

2005 ◽  
Vol 127 (1) ◽  
pp. 1-6
Author(s):  
Tilman Diesselhorst ◽  
Ulrich Neumann
Keyword(s):  
Fluid Structure Interaction ◽  
Check Valve ◽  
System Behavior ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Fluid Forces ◽  
Piping Systems ◽  
Valve Function ◽  
Design Loads ◽  
Pressure Surge

To reduce costs and to extend the lifetime of piping systems their design loads due to valve action have to be optimized. To get the best effect the results of the fluiddynamic and structural calculations should be realistic as far as possible. Therefore, the calculation programs were coupled to consider the fluid structure interaction and the effect of dynamic fluid friction was introduced to get realistic results of oscillations due to pressure surges. Detailed modeling of check valve behavior allows minimizing the pressure surge loading by improving the valve function and adapting it to the system behavior. The method was validated at measurements of load cases in power plant piping systems. Results with different load cases show the effectiveness of reducing the fluid forces on piping. Examples are given to prove the reduction of supports.

scholarly journals Linear Stability Analysis and Validation of a Unified Solution Method for Fluid-Structure-Interaction on Structural Dynamic Problems

2005 ◽  
Author(s):  
C. G. Giannopapa ◽  
G. Papadakis
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Solution Method ◽  
Fluid Structure Interaction ◽  
Analytic Solutions ◽  
Computational Domain ◽  
Structural Dynamic ◽  
Fluid Structure ◽  
Structure Interaction

In the conventional approach for fluid-structure interaction problems, the fluid and solid components are treated separately and information is exchanged across their interface. According to the conventional terminology, the current numerical methods can be grouped in two major categories: Partitioned methods and monolithic methods. Both methods use two separate sets of equations for fluid and solid. A unified solution method has been presented [1], which is different from these methods. The new method treats both fluid and solid as a single continuum, thus the whole computational domain is treated as one entity discretised on a single grid. Its behavior is described by a single set of equations, which are solved fully implicitly. In this paper, 2 time marching and one spatial discretisation scheme, widely used for fluids’ equations, are applied for the solution of the equations for solids. Using linear stability analysis, the accuracy and dissipation characteristics of the resulting difference equations are examined. The aforementioned schemes are applied to a transient structural problem (beam bending) and the results compare favorably with available analytic solutions and are consistent with the conclusions of the stability analysis. A parametric investigation using different meshes, time steps and beam sizes is also presented. For all cases examined the numerical solution was stable and robust and proved to be suitable for the next stage of application to full fluid-structure interaction problems.

Free Vibration and Thermal Fluid Structure Interaction Simulation of Functionally Graded Pipe by Modeling As Layered Structure

2020 ◽  
Author(s):  
Ziyi Su ◽  
Kazuaki Inaba ◽  
Amit Karmakar ◽  
Apurba Das
Keyword(s):  
Free Vibration ◽  
Layered Structure ◽  
Volume Fraction ◽  
Fluid Structure Interaction ◽  
Functionally Graded ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Layered Model ◽  
Piping Systems ◽  
Complex Phenomena

Abstract Functionally graded materials (FGMs) are advanced class of composite materials which can be used as the thermal barrier to protect inner components from the outside high temperature environment. In FGMs, the volume fraction of each constituent can be tailored made across the thickness for desired applications. In this work, the simulation of FGMs in pipes is considered. Despite the wide application of pipes in machinery, those pipes would suffer from many safety problems, such as thermal stress, cavitation, fracture etc. Application of FGMs to the piping systems could lead to some new solutions accounting for safety measures and higher service life. However, the complex phenomena within the fluid structure interaction are hard to describe with the theoretical solution. The visualization of results from simulation will be helpful in understanding the distribution of kinds of physical quantities within the concerned model. For the simulation, FGMs are modeled as the layered structure in the standard finite element method (FEM) package based on FGM constituent law. The free vibration of the FG pipe is simulated and the accuracy of layered model is verified by numerical calculations. Further, based on the layered model, conjugate heat transfer simulations in a heat exchanger with FGMs are conducted.

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.

Frequency Domain Analysis of Vibrations in Liquid-Filled Piping Systems

1999 ◽  
Author(s):  
Zongxia Jiao ◽  
Qing Hua ◽  
Kai Yu
Keyword(s):  
Frequency Domain ◽  
Transfer Matrix ◽  
Fluid Structure Interaction ◽  
Viscous Friction ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Piping System ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Piping Systems

Abstract In the analysis of liquid-filled piping systems there are Poisson-coupled axial stress waves in the pipe and liquid column, which are caused by the dilation of the pipe. In some conditions the influence of viscous friction that is usually frequency-dependent should not be omitted, which in fact is another kind of coupled form. It directly influences the amplitude of vibration of piping systems to some degree. The larger the viscosity of the liquid is, the greater the influence will be. Budny (1991) included the viscous friction influence in time domain analysis of fluid-structure interaction, but did not give frequency domain analysis. Lesmez (1990) gave the model analysis liquid-filled piping systems without considering friction. If the friction is not included in frequency domain analysis, the vibration amplitude will be greater than that when friction is included, especially at harmony points, cause large errors in the simulation of fluid pipe network analysis, although it may have little influence on the frequency of harmony points. The present paper will give detail solutions to the transfer matrix that represents the motion of single pipe section, which is the basis of complex fluid-structure interaction analysis. Combined with point matrices that describe specified boundary conditions, overall transfer matrix for a piping system can be assembled. Corresponding state vectors can then be evaluated to predict the piping and liquid motion. At last, a twice-coordinate transformation method is adopted in joint coupling. Consequently, the vibration analysis of spatial liquid-filled piping systems can be carried out. It is proved to be succinct, valid and versatile. This method can be extended to the simulation of the curved spatial pipeline systems.

Coupled Calculation on Fluid Structure Interaction in Plate-Type Fuel Element

2018 ◽  
Author(s):  
Yiqi Yu ◽  
Elia Merzari ◽  
Jerome Solberg
Keyword(s):  
Fuel Element ◽  
Fluid Structure Interaction ◽  
Initial Step ◽  
University Of Missouri ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Coupled Calculation ◽  
Enriched Uranium ◽  
Type Fuel ◽  
Plate Type

In nuclear reactors that use plate-type fuel, the fuel plates are thermally managed with coolant flowing through channels between the plates. Depending on the flow rates and sizes of the fluid channels, the hydraulic forces exerted on a plate can be quite large. Currently, there is a worldwide effort to convert research reactors that use highly enriched uranium (HEU) fuel, some of which are plate-type, to low-enriched uranium (LEU). Because of the proposed changes to the fuel structure and thickness, a need exists to characterize the potential for flow-induced deflection of the LEU fuel plates. In this study, as an initial step, calculations of Fluid-Structure Interaction (FSI) for a flat aluminum plate separating two parallel rectangular channels are performed using the commercial code STAR-CCM+ and the integrated multi-physics code SHARP, developed under the Nuclear Energy Advanced Modeling and Simulation program. SHARP contains the high-fidelity single physics packages Diablo and Nek5000, both highly scalable and extensively validated. In this work, verification studies are performed to assess the results from both STAR-CCM+ and SHARP. The predicted deflections of the plate agree well with each other as well as exhibiting good agreement with simulations performed by the University of Missouri utilizing STAR-CCM+ coupled with the commercial structural mechanics code ABAQUS. The study provides a solid basis for FSI modeling capability for plate-type fuel element with SHARP.

scholarly journals Inflatable Leading Edge-Based Dynamic Stall Control considering Fluid-Structure Interaction

2020 ◽  
Vol 2020 ◽  
pp. 1-28
Author(s):  
Shi-Long Xing ◽  
He-Yong Xu ◽  
Ming-Sheng Ma ◽  
Zheng-Yin Ye
Keyword(s):  
Lift Coefficient ◽  
Fluid Structure Interaction ◽  
Leading Edge ◽  
Dynamic Stall ◽  
Elastic Membrane ◽  
Radius Of Curvature ◽  
Structural Dynamic ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Stall Control

The inflatable leading edge (ILE) is explored as a dynamic stall control concept. A fluid-structure interaction (FSI) numerical method for the elastic membrane structure is constructed based on unsteady Reynolds-averaged Navier-Stokes (URANS) and a mass-spring-damper (MSD) structural dynamic model. Radial basis function- (RBF-) based mesh deformation algorithm and Laplacian and optimization-based mesh smoothing algorithm are adopted in flowfield simulations to achieve the pitching oscillation of the airfoil and to ensure the mesh quality. An airfoil is considered at a freestream Mach number of 0.3 and chord-based Reynolds number of 3.92×106. The airfoil is pitched about its quarter-chord axis at a sinusoidal motion. The numerical results indicate that the ILE can change the radius of curvature of the airfoil leading edge, which could reduce the streamwise adverse pressure gradient and suppress the formation of dynamic stall vortex (DSV). Although the maximum lift coefficient of the airfoil is slightly reduced during the control process, the maximum drag and pitching moment coefficients of the airfoil are greatly reduced by up to 66% and 75.2%, respectively. The relative position of the ILE has a significant influence on its control effect. The control laws of inflation and deflation also affect the control ability of the ILE.

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