A multi-stage approach of simulating turbulence-induced vibrations in a wire-wrapped tube bundle for fretting wear prediction

2022 ◽  
Vol 109 ◽  
pp. 103460
Author(s):  
Henri Dolfen ◽  
Jeroen De Ridder ◽  
Landon Brockmeyer ◽  
Elia Merzari ◽  
Graham Kennedy ◽  
...  
Keyword(s):  
Tube Bundle ◽  
Fretting Wear ◽  
Wear Prediction ◽  
Multi Stage

Vibration Excitation Forces in a Rotated Triangular Tube Bundle Subjected to Two-Phase Cross Flow

2010 ◽  
Author(s):  
H. Senez ◽  
N. W. Mureithi ◽  
M. J. Pettigrew
Keyword(s):  
Steam Generator ◽  
Tube Bundle ◽  
Cross Flow ◽  
Fretting Wear ◽  
Experimental Program ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Fluid Forces ◽  
Vibration Excitation

Two-phase cross flow exists in many shell-and-tube heat exchangers. Flow-induced vibration excitation forces can cause tube motion that will result in long-term fretting wear or fatigue. Detailed flow and vibration excitation force measurements in tube bundles subjected to two-phase cross flow are required to understand the underlying vibration excitation mechanisms. Studies on this subject have already been done, providing results on flow regimes, fluidelastic instabilities, and turbulence-induced vibration. The spectrum of turbulence-induced forces has usually been expected to be similar to that in single-phase flow. However, a recent study, using tubes with a diameter larger than that in a real steam generator, showed the existence of significant quasi-periodic forces in two-phase flow. An experimental program was undertaken with a rotated-triangular array of cylinders subjected to air-water cross-flow, to simulate two-phase mixtures. The tube bundle here has the same geometry as that of a real steam generator. The quasi-periodic forces have now also been observed in this tube bundle. The present work aims to understand turbulence-induced forces acting on the tube bundle, providing results on drag and lift force spectra and their behaviour according to flow parameters, and describing their correlations. Detailed experimental test results are presented in this paper. Comparison is also made with previous measurements with larger diameter tubes. The present results suggest that quasi-periodic fluid forces are not uncommon in tube arrays subjected to two-phase cross-flow.

Fluidelastic Instability and Periodic Fluid Forces in a Normal Triangular Tube Bundle Subjected to Air-Water Flow

2010 ◽  
Author(s):  
G. Ricciardi ◽  
M. J. Pettigrew ◽  
N. W. Mureithi
Keyword(s):  
Two Phase Flow ◽  
Tube Bundle ◽  
Fatigue Cracks ◽  
Cross Flow ◽  
Fretting Wear ◽  
Phase Flow ◽  
Steam Generators ◽  
Two Phase ◽  
Fluid Forces ◽  
Void Fractions

Two-phase flow in power plant steam generators can induce tube vibrations, which may cause fretting-wear and even fatigue cracks. It is therefore important to understand the relevant two-phase flow-induced vibration mechanisms. Fluidelastic instabilities in cross-flow are known to cause the most severe vibration response in the U-bend region of steam generators. This paper presents test results of the vibration of a normal triangular tube bundle subjected to air-water cross-flow. The test section presents 31 flexible tubes. The pitch-to-diameter ratio of the bundle is 1.5, and the tube diameter is 38 mm. Tubes were flexible in the lift direction. Seven tubes were instrumented with strain gauges to measure their displacements. A broad range of void fractions (from 10% to 90%) and fluid velocities (up to 13 m/s) were tested. Fluidelastic instabilities were observed for void fractions between 10% and 60%. Periodic fluid forces were also observed. The results are compared with those obtained with the rotated triangular tube bundle, showing that the normal triangular configuration is more stable than the rotated triangular configuration.

Vibration Excitation Force Measurements in a Rotated Triangular Tube Bundle Subjected to Two-Phase Cross Flow

2005 ◽  
Author(s):  
C. Zhang ◽  
M. J. Pettigrew ◽  
N. W. Mureithi
Keyword(s):  
Tube Bundle ◽  
Cross Flow ◽  
Fretting Wear ◽  
Experimental Program ◽  
Force Measurements ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Drag Forces ◽  
Vibration Excitation ◽  
Excitation Force

Two-phase cross flow exists in many shell-and-tube heat exchangers. Flow-induced vibration excitation forces can cause tube motion that will result in long-term fretting-wear or fatigue. Detailed vibration excitation force measurements in tube bundles subjected to two-phase cross flow are required to understand the underlying vibration excitation mechanisms. An experimental program was undertaken with a rotated-triangular array of cylinders subjected to air/water flow to simulate two-phase mixtures over a broad range of void fraction and mass fluxes. Both the dynamic lift and drag forces were measured with strain gage instrumented cylinders. The experiments revealed somewhat unexpected but significant quasi-periodic forces in both the drag and lift directions. The periodic forces appeared well correlated along the cylinder with the drag force somewhat better correlated than the lift forces. The periodic forces are also dependent on the position of the cylinder within the bundle.

High temperature fretting wear prediction of exhaust valve material

2016 ◽  
Vol 100 ◽  
pp. 280-286 ◽  
Author(s):  
D. Kesavan ◽  
Vamshidhar Done ◽  
M.R. Sridhar ◽  
Ronald Billig ◽  
Daniel Nelias
Keyword(s):  
High Temperature ◽  
Exhaust Valve ◽  
Fretting Wear ◽  
Wear Prediction

Turbulence-Induced Vibration of Tube Bundle in Cross and Parallel Jet Mixed Flow

1989 ◽  
Vol 111 (4) ◽  
pp. 352-360 ◽  
Author(s):  
K. Kawamura ◽  
A. Yasuo
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Flow Field ◽  
Tube Bundle ◽  
Cross Flow ◽  
Jet Flow ◽  
Fretting Wear ◽  
Baffle Plate ◽  
Mixed Flow ◽  
The Cross

In the multi-tube type of heat exchanger, baffle plates are located at appropriate intervals to support the heat transfer tubes. Depending on the baffle plate type employed, the flow field in the tube bundle will consist of a mixture of the cross flow (the fluid flows at right angles to the tube bundle along the baffle plate surfaces) and the parallel jet flow (the fluid streams through channels such as the flow holes of the baffle plates in the form of jets and flows in parallel with the tube bundle). Vibrations induced by the flow can cause fretting wear and fatigue of the heat transfer tubes. Therefore, it it essential to establish a method of evaluating heat transfer tube vibrations induced by the mixed flow for the purpose of evaluating the integrity of heat exchanger tubes. In this paper, three different flows, that is, cross, parallel jet and mixed flows, were simulated in order to clarify the relationships between the flow conditions and vibration of the tube bundle, and to study a method for evaluating tube bundle vibrations induced by turbulence in the mixed flow field by using the vibration characteristics in the cross flow field and the parallel jet flow field.

Fluidelastic Instability Modeling of Loosely Supported Multispan U-Tubes in Nuclear Steam Generators

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Marwan Hassan ◽  
Atef Mohany
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Complex Dynamics ◽  
Tube Bundle ◽  
Design Guidelines ◽  
Fretting Wear ◽  
Contact Ratio ◽  
Steam Generators ◽  
Fluidelastic Instability ◽  
Wear Damage

Steam generators in nuclear power plants have experienced tube failures caused by flow-induced vibrations. Two excitation mechanisms are responsible for such failures; random turbulence excitation and fluidelastic instability. The random turbulence excitation mechanism results in long-term failures due to fretting-wear damage at the tube supports, while fluidelastic instability results in short-term failures due to excessive vibration of the tubes. Such failures may require shutdowns, which result in production losses, and pose potential threats to human safety and the environment. Therefore, it is imperative to predict the nonlinear tube response and the associated fretting-wear damage to tubes due to fluid excitation. In this paper, a numerical model is developed to predict the nonlinear dynamic response of a steam generator with multispan U-tubes and anti-vibration bar supports, and the associated fretting wear due to fluid excitation. Both the crossflow turbulence and fluidelastic instability forces are considered in this model. The finite element method is utilized to model the vibrations and impact dynamics. The tube bundle geometry is similar to the geometry used in CANDU steam generators. Eight sets of flat-bar supports are considered. Moreover, the effect of clearances between the tubes and their supports, and axial offset between the supports are investigated. The results are presented and comparisons are made for the parameters influencing the fretting-wear damage, such as contact ratio, impact forces, and normal work rate. It is clear that tubes in loose flat-bar supports have complex dynamics due to a combination of geometry, tube-to-support clearance, offset, and misalignment. However, the results of the numerical simulation along with the developed model provide new insight into the flow-induced vibration mechanism and fretting wear of multispan U-tubes that can be incorporated into future design guidelines for steam generators and large heat exchangers.

Development of a Numerical Model to Represent Two-Phase Flow Configurations in a Tube Bundle

2011 ◽  
Author(s):  
Hubert Senez ◽  
Ste´phane E´tienne
Keyword(s):  
Numerical Model ◽  
Tube Bundle ◽  
Cross Flow ◽  
Fretting Wear ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Flow Configuration ◽  
Drag Forces ◽  
Flow Configurations ◽  
Two Bubbles

Two-phase cross-flow exists in many shell-and-tube heat exchangers. Flow-induced vibration excitation forces can cause tube motion that will result in long-term fretting wear or fatigue. Studies on the subject, providing results on turbulence-induced displacement, fluid-elastic instabilities, and flow patterns have already been performed. It has been shown that the flow configuration plays an important role in the vibrations excitation mechanism. Previous studies showed the existence of unexpected quasi-periodic forces acting on a tube bundle subjected to two-phase cross-flow. The present work aims to understand the physical origin of these forces. A simple numerical model was developed to simulate two-phase cross-flow acting on a tube bundle. This model considers a continuous liquid potential flow across a tube bundle, with virtual bubbles being introduced in the flow. Three kinds of forces act on the bubbles: buoyancy forces, drag forces, and impact forces. These forces take place between two bubbles, or between a bubble and a cylinder. Two bubbles may coalesce if they hit each other, and conversely a bubble may split into two bubbles if the shear flow is strong enough. These local considerations on bubbles have global consequences on the flow configuration. Preliminary results show similarities between the numerical flow configuration and the experiments.

Flow-Induced Vibration and Fretting-Wear Performance of CANDU™ Steam Generator U-Tubes: Instrumentation

2009 ◽  
Author(s):  
Atef Mohany ◽  
Victor Janzen
Keyword(s):  
Steam Generator ◽  
Tube Bundle ◽  
Measurement Techniques ◽  
Fretting Wear ◽  
Process Conditions ◽  
Steam Quality ◽  
Steam Generators ◽  
Test Program ◽  
Two Phase ◽  
Support Design

This paper describes a test program that was developed to measure the dynamic response of a bundle of steam generator U-tubes with Anti-Vibration Bar (AVB) supports, subjected to Freon two-phase cross-flow. The tube bundle has similar geometrical conditions to those expected for future CANDU™ steam generators. Future steam generators will be larger than previous CANDU steam generators, nearly twice the heat transfer area, with significant changes in process conditions in the U-bend region, such as increased steam quality and a broader range of flow velocities. This test program is one of the initiatives that AECL is undertaking to demonstrate that the tube support design for future CANDU steam generators meets the stringent requirements associated with a 60 year lifetime. The main objective of the tests is to address the issue of in- and out-of-plane fluidelastic instability and random turbulent excitation of a U-tube bundle with AVB supports. Details of the test rig, measurement techniques and preliminary instrumentation results are described in the paper.

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