Analysis of the Leakage-Flow-Induced Vibration of a Slip Joint in a Jet Pump of a Boiling Water Reactor

2019 ◽  
Vol 390 ◽  
pp. 23-31 ◽  
Author(s):  
J. Cruz Castro ◽  
E. Hernández Palafox ◽  
I.A. Alarcón Sánchez ◽  
Luis H. Hernández-Gómez ◽  
Pablo Ruiz-López ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Natural Frequencies ◽  
Excitation Frequency ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Jet Pump ◽  
Flow Induced Vibration ◽  
Ansys Fluent ◽  
Pump Assembly ◽  
Fourth Mode

The purpose of this analysis is to evaluate the structural integrity of the jet pump assembly of a BWR during the performance of its operational and safety functions. The natural frequencies and vibration modes of the jet pump assembly immersed in water were determined. It was observed that the fourth mode shape was torsional, and its associated resonance frequency was 41.82 Hz. Also, the vibration induced by the flow in the leakage of the slip joint was analyzed with an axisymmetric model. The gap of the slip joint was varied from 0.2 mm until 0.65bmm. A gap between 0.6 and 0.64, would cause flow-induced vibration because this excitation frequency matches with the fourth natural frequency of the jet pump assembly. The above was carried out using computational fluid dynamics, as well as the finite element method, with ANSYS Structural and ANSYS Fluent codes.

Evaluation of the Structural Integrity of the Jet Pumps of a Boiling Water Reactor under Hydrodynamic Loading

2014 ◽  
Vol 348 ◽  
pp. 261-270 ◽  
Author(s):  
Noel M. Cuahquentzi ◽  
Luis H.H. Gómez ◽  
Pablo R. López ◽  
Guillermo Urriolagoitia-Calderón ◽  
Juan Alfonso Beltrán-Fernández ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Natural Frequencies ◽  
Boiling Water ◽  
Boiling Water Reactor ◽  
Main Function ◽  
Jet Pump ◽  
Water Reactor ◽  
Hydrodynamic Loading ◽  
Jet Pumps ◽  
Pump Assembly

The structural integrity of a jet pump assembly of a boiling water reactor (BWR) under hydrodynamic loading was evaluated. This arrangement, which has a riser joined with a couple of jet pumps by the transition piece, is part of the reactor recirculation system. It is submerged in water under pressure. The main function is to induce forced flow through the core of the reactor. A dynamic structural analysis was carried out with the finite element method. The first ten modes of vibration and their natural frequencies were calculated. The first five natural frequencies are in the range between 25 Hz and 40 Hz. In this analysis, it was considered that the jet pump assembly is supported at the riser brace. The restrainer bracket keeps together the riser with the two jet pumps and there is free movement at the slip joints.

scholarly journals Influence of the flexibility of beams and slabs in static response and dynamic properties

2016 ◽  
Vol 9 (6) ◽  
pp. 842-855 ◽  
Author(s):  
J. R. BUENO ◽  
◽  
D. D. LORIGGIO ◽  
Keyword(s):  
Finite Element Method ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Vibration Modes ◽  
Linear Regime ◽  
Static Response ◽  
The Finite Element Method ◽  
Standard Code ◽  
The Relationship ◽  
Brazilian Standard

Abstract This article examines numerically the flexibility influence of support beams in static response and dynamic properties of a symmetric plate formed by massive slabs of reinforced concrete in elastic linear regime, using the Finite Element Method. In the static response the variation of bending mo-ments and displacements are evaluated, which depend on the relationship between the flexibility of the slab and the beam. The evaluation of dynamic properties is held in undamped free vibration, through which the vibration modes and the values of the natural frequencies is obtained, which are compared with the limits of the Brazilian standard code for design of concrete structures. Results show that the response may show great variation due to the change in the relationship between bending stiffness of the slabs and the beams.

An Approach on Tuning the Frequency of a Rotating Blade

2008 ◽  
Author(s):  
L. Duong ◽  
K. Kazerounian ◽  
K. D. Murphy
Keyword(s):  
Structural Integrity ◽  
Natural Frequencies ◽  
Vibration Mode ◽  
The Finite Element Method ◽  
Turbine Engine ◽  
Rotating Blade ◽  
Alternative Approach ◽  
Excited Vibration ◽  
Speed Range ◽  
Analytical Expressions

In a gas turbine engine, the forced vibration of a turbine blade under resonant conditions is undesirable and may lead to premature high cycle fatigue failure. From the aspect of structural integrity, this demonstrates that it is extremely important to tune the excited vibration mode out of the operating speed range. This leads to the question: Is it possible to perform structural perturbations, namely to the mass and stiffness, in such a way that only the eigenvalue of choice significantly changes — while causing little or no change in the other natural frequencies? This is focus of the present paper. Due to the complexity of the blade structure, it is difficult to obtain an analytical solution from the eigenvalue perturbation theory. Nevertheless, the derived analytical expressions provide guidance from which the finite element method may successfully be applied as an alternative approach. This tuning approach is validated experimentally.

Fluid-Structural Interaction in a Slip Joint of a Jet Pump Assembly of a BWR-5

2020 ◽  
Vol 399 ◽  
pp. 105-114
Author(s):  
Juan Cruz Castro ◽  
Yunuén López Grijalba ◽  
Luis Héctor Hernández Gómez ◽  
Israel Abraham Alarcón Sánchez ◽  
Pablo Ruiz López ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Reactor ◽  
Mechanical Damage ◽  
Steel Plates ◽  
Jet Pump ◽  
Flow Induced Vibration ◽  
Structural Interaction ◽  
Pump Assembly ◽  
Volume Method

Flow-induced vibrations occur in some of the internal components of a nuclear reactor. When specific conditions are present, these vibrations may result in excessive deformations or fatigue that can generate mechanical damage. Several boiling water reactor (BWR) of nuclear power plants (NPP) have experienced failures in the jet pump assembly due to flow-induced vibration (FIV) which could be caused by acoustic pulsations derived from recirculation pumps, vibration induced by turbulence and vibration induced by leakage at the slip joint. The purpose of this paper is to establish a viable numerical methodology to evaluate the fluid-structural interaction at the slip joint of a jet pump. In this analysis, the fluid-structural interaction was evaluated with the finite element method and finite volume method with ANSYS® code in the case of two steel plates with a divergent gap. Results show that a critical velocity could cause fluidelastic instability, if only one flow in a two-way fluid-structural interaction was considered. This is one of the phenomena that could take place at the slip joint of a jet pump assembly.

scholarly journals Component Mode Synthesis Method Applied to Acoustic Resonators in Ducts for Structural Vibration Analysis

2020 ◽  
Vol 25 (4) ◽  
pp. 498-503
Author(s):  
Jose Manuel Bautista Ordóñez ◽  
Maria Alzira de Araújo Nunes
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Component Mode Synthesis ◽  
Structural Vibration ◽  
Structural Systems ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Element Method

Tubular structural systems appear in many industrial applications, such as heating, ventilation, and air conditioning systems, which are responsible for making any enclosed environment remain within a temperature, humidity, and cleanliness range. This kind of system has its applications in the internal environmental comfort of industrial spaces, buildings, and vehicles. Several of these spaces have industrial processes that generate high sound frequencies and mechanical vibrations that need to be adequately controlled to meet both environmental and health norms. With the intention to analyze the structural vibration of tubular systems, the modal analysis technique is a classical methodology for the extraction of natural frequencies and vibration modes. Among the various techniques of modal analysis, numerical methodologies such as the finite element method, and also analytical methodologies such as the Component Mode Synthesis (CMS) can be found. CMS is one of the leading modeling tools for complex systems that are applied to large systems. The method uses a modal superset and consists of separately modeling individual components of a structure and coupling them into a single system. The objective of this work is to demonstrate the application of the CMS technique through the estimation of natural frequencies and vibration modes in a simplified tubular structural system formed by two substructures, using MATLAB and ANSYS. The validation of the results was done through numerical modeling using the finite element method using and ANSYS software. The results obtained were satisfactory, thus demonstrating the feasibility of applying the CMS technique to an analysis of structural vibration in tubular structural systems.

scholarly journals Analysis of Excitation and Dead Vibration Modes of Quartz Resonators

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Zi-Gui Huang ◽  
Zheng-Yu Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Resonance Frequency ◽  
Plane Strain ◽  
Excitation Frequency ◽  
Three Dimensional ◽  
Vibration Modes ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Natural Vibrations

This study uses the finite element method (FEM) to analyze the excitation and dead vibration modes of two-dimensional quartz plates. We first simplify three-dimensional quartz plates with plane strain simplification and then compare the modes of the simplified three-dimensional plates to those of two-dimensional plates. We then analyze quartz vibrating elements of AT-cut plates and SC-cut plates. To understand the regularity of the resonance frequency of plates that are excitable by voltage loading, we compare the natural vibrations of quartz plates with the excitation frequency generated after the plates are excited by voltage loading.

scholarly journals Structural Modeling and Modal Analysis of Hot-line Work Across the Line Construction

2018 ◽  
Vol 232 ◽  
pp. 02011
Author(s):  
Li Xu ◽  
Yanyi Fu ◽  
Hui Li ◽  
Lihua Xiao ◽  
Hao Guo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
Nonlinear Structures ◽  
The Finite Element Method ◽  
Transient Dynamic Analysis ◽  
Initial Shape ◽  
Line Construction ◽  
Line Work

For the nonlinear structures such as traverse and mesh spanning structure, it is very difficult to analyze the traditional calculation method. The initial shape of the structure is determined by the finite element method and the accuracy of the model is verified. Based on this model, the natural frequencies and vibration modes of the structure are analyzed and determined, which can provide reference for transient dynamic analysis.

Vibration Localization in Plates With Misplaced Intermediate Supports in Two Orthogonal Directions

2003 ◽  
Author(s):  
Wei-Chau Xie ◽  
Zhihua Chen
Keyword(s):  
Forced Vibration ◽  
Natural Frequencies ◽  
Current Approach ◽  
Vibration Response ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Concentrated Load ◽  
Vibration Localization ◽  
Vibration Responses ◽  
Simple Supports

This paper investigates the effect of small misplacements on both the free vibration modes and forced vibration responses of a four-panel simply supported plate with two intermediate simple supports in two orthogonal directions. Kantorovich’s method is employed to obtain the natural frequencies and the corresponding vibration modes. Galerkin’s method is applied to determine the forced vibration response of the four-panel plate subjected to a harmonic concentrated load at the center of one of its four panels. Comparisons between numerical results obtained using the current approach and those using the exact solution and the finite element method are made to demonstrate the accuracy of the current approach. It is found that the small misplacements of the intermediate supports have dramatic effects on the vibration response of the plate. The larger the misplacement of the intermediate supports, the larger the degree of vibration localization. By judiciously introducing misplacements in the intermediate simple supports, the vibration of some of the four panels may be controlled.

scholarly journals Cross Flow Analysis over the Jet Pumps of a BWR-5 Reactor

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
G. Soto-Mendoza ◽  
A. Armenta-Molina ◽  
S. Pérez-Montejo ◽  
L.H. Hernández-Gómez ◽  
P. Ruiz-López ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Natural Circulation ◽  
Flow Analysis ◽  
Cross Flow ◽  
Numerical Approach ◽  
Main Function ◽  
Vortex Generation ◽  
Jet Pump ◽  
Jet Pumps ◽  
Pump Assembly

The recirculation system of a BWR-5 has 20 jet pumps. They are submerged in water in the cylindrical annular zone of the reactor. Their main function is the development of a forcing flow through the nuclear core. It increases the power of the reactor compared with the one obtained by natural circulation. These components have an important safety function in the operation of the reactor. In accordance with document BWRVIP-41 R4, it was concluded that the vibration induced by cross flow over the jet pump assemblies is one of the degradation mechanisms of such pumps. In this paper, the vibration induced by the cross flow at a jet pump assembly BWR-5 was analyzed. A numerical approach was developed. The natural frequencies were obtained, considering the Fluid-Structure Interaction (FSI). The first natural frequency was 25.7 Hz. A Computational Fluid Dynamics (CFD) analysis was carried, in conjunction with the Power Spectral Density (PSD). A frequency of vortex generation of 0.48 Hz was obtained. A vortex generation analysis was carried out with the Q-criteria. The results showed that resonance conditions are unlikely. Therefore, the structural integrity of the jet pump assemblies is maintained.

Vibration Internal Characteristics Research on the Turbocharger Rotor

2012 ◽  
Vol 516-517 ◽  
pp. 709-713
Author(s):  
Jun Sheng Zhao ◽  
Liao Ping Hu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Natural Frequencies ◽  
Vibration Modes ◽  
The Finite Element Method ◽  
Rotating Speed ◽  
Bearing Stiffness ◽  
Film Stiffness ◽  
Test Result ◽  
Element Method

In order to obtain the vibration characteristics of the turbocharger rotor system, its natural frequencies and vibration modes are approached by the experimental method and the finite element method. The modal parameters are obtained by modal tests, and are calculated by the finite element method with the software ANSYS8.0 at the meantime. The influence is approached mainly for the oil film stiffness of the floating-ring bearings and the rotor’s rotating speed. The FEM result is certificate compared with the modal test result. The influence of the rotating speed is greater on the rotor natural frequency than that of the bearing stiffness. It provides the theoretical basis for turbocharger’s vibration control and structure improve.

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