Prevention and Cure of Flow-Induced Vibration Problems in Tubular Heat Exchangers

1980 ◽  
Vol 102 (2) ◽  
pp. 138-145 ◽  
Author(s):  
F. L. Eisinger
Keyword(s):  
Heat Exchangers ◽  
Cross Flow ◽  
Acoustic Vibration ◽  
New Method ◽  
Flow Induced Vibration ◽  
Tube Bank ◽  
Vibration Resistance ◽  
Stability Diagrams ◽  
Vibration Problems ◽  
Prevention And Cure

Various methods for predicting and solving tube and acoustic vibration problems in heat exchangers in cross flow are presented: the use of stability diagrams comprising in-service experience of heat exchangers, for a general multispan tube model; a method of selecting efficient baffle configurations for prevention of acoustic vibration, a new method of fin barriers, an alternative to conventional baffling; a new method of enhancing the vibration resistance of a tube bank based on the use of a helical spacer; these methods, singly or in combination, can be used to design against flow-induced vibration.

Mesh Shape Preservation for Flow-Induced Vibration Problems

2002 ◽  
Author(s):  
R. M. C. So ◽  
Y. Liu ◽  
Y. G. Lai
Keyword(s):  
Numerical Technique ◽  
Three Dimensional ◽  
Cross Flow ◽  
Physical Space ◽  
Shape Preservation ◽  
Structural Vibration ◽  
Flow Induced Vibration ◽  
Time Step ◽  
Dimensional Flow ◽  
Vibration Problems

This paper describes a numerical technique that can prevent the mesh from severe distortion in flow-induced vibration calculations. An orthogonal transformed space that is related to the physical space through a Laplacian equation is introduced. At each time step, the mesh may deform significantly in the physical space due to structural vibration, but the mesh nodal value in the transformed space remains constant. As long as the coordinates in the physical space can be adjusted to render the transformed space independent of time, the mesh shape in the physical space is preserved, even though the mesh area may enlarge or reduce significantly. For simplicity, a two-dimensional flow-induced vibration problem is used to illustrate this method. Two side-by-side elastic cylinders in a cross flow are considered. The Reynolds number is fixed at 200 so that a laminar wake is still available. The mass ratio is chosen to be small so that large displacements of the cylinders can be realized. The predictions with and without mesh preservation are compared. The difference between the two results could be as large as 25% in the prediction of the mean transverse displacements of the cylinders. The method could be extended to three-dimensional flow-induced vibration problems without much difficulty.

Flow-Induced Vibration and Noise in Tube-Bank Heat Exchangers Due to von Karman Streets

1968 ◽  
Vol 90 (1) ◽  
pp. 134-146 ◽  
Author(s):  
Y. N. Chen
Keyword(s):  
Wind Tunnel ◽  
Vortex Shedding ◽  
Heat Exchangers ◽  
Flow Induced Vibration ◽  
Tube Bank ◽  
Von Karman ◽  
Von Kármán Streets ◽  
Von Kármán

This paper treats the problem of vibration and noise in tube-bank heat exchangers. The frequency of vortex shedding has been investigated by many authors, and their results have varied considerably. The author, in previous works, correlated these different data into a curve group of his own, and now proceeds to further analyze the problem. Results of experiments performed in a small wind tunnel are given, accompanied by typical graphs. Based on his findings, the author concludes with some design proposals for suppressing vibrations.

Fluid Elastic Whirling of a Tube Row

1974 ◽  
Vol 96 (4) ◽  
pp. 263-267 ◽  
Author(s):  
R. D. Blevins
Keyword(s):  
Natural Frequency ◽  
Analytical Model ◽  
Heat Exchangers ◽  
Free Stream ◽  
Cross Flow ◽  
Flow Induced Vibration ◽  
Adjacent Wall

An analytical model for flow-induced vibration of a tube row in a cross flow is formulated. A criterion for the onset of instability is developed. The tubes are modeled with different stiffnesses and damping normal and parallel to the free stream to simulate effects which arise in heat exchangers. The critical reduced velocity required for the onset of instability is shown to increase sharply with the separation of natural frequency between tubes. The effect of an adjacent wall and rows composed of a small number of tubes is explored. The model reduces to an experimentally validated criterion for symmetrically supported tubes.

A Study About Performance Evaluation Criteria of Tube Banks With Various Shapes and Arrangements Using Numerical Simulation

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Amin Jodaei ◽  
Kamiar Zamzamian
Keyword(s):  
Heat Transfer ◽  
Performance Evaluation ◽  
Heat Exchangers ◽  
Three Dimensional ◽  
Evaluation Criteria ◽  
Cross Flow ◽  
Transfer Coefficients ◽  
Tube Bank ◽  
Shaped Tube ◽  
Tube Banks

Tube bank heat exchangers are designed to efficiently transfer heat between two fluids. Shapes and arrangements of tubes in heat exchangers have significant effects in heat transfer and pressure drop of fluid. In this study, the three-dimensional (3D) numerical investigation is performed to determine heat transfer coefficients, friction factor, and performance evaluation criteria (PEC) of cam-shaped tube banks in aerodynamic and inverse aerodynamic directions in the cross flow air and compared with those of elliptical tube banks in heat exchanger. The arrangements of tubes are aligned and staggered with longitudinal pitch of 44.88 mm and transverse pitch of 28.05 mm. Reynolds number in the range of 11,500–18,500 was used, and the tube surface temperature was fixed and considered 352 K. Results indicate the superior heat transfer of elliptical tube bank over the cam-shaped tube banks in inverse aerodynamic and aerodynamic directions in both arrangements. Moreover, the PEC of the cam-shaped tube banks with inverse aerodynamic and aerodynamic directions and elliptical tube bank in aligned arrangement are approximately 1.4, 1.1, and 1.6, respectively. The obtained results for staggered arrangements are also 1.5, 1.3, and 1.8, respectively.

Prediction of Flow-Induced Vibrations in Tubular Heat Exchangers—Part II: Experimental Investigation

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
S. A. Al-Kaabi ◽  
Y. A. Khulief ◽  
S. A. Said
Keyword(s):  
Heat Exchangers ◽  
Complex Dynamics ◽  
Cross Flow ◽  
Analytical Models ◽  
Test Rig ◽  
Flow Induced Vibration ◽  
Tube Arrays ◽  
Tube Bundles ◽  
Flow Induced Vibrations ◽  
The Mathematical Model

It has become evident that the modeling of the complex dynamics of fluidelastic forces that give rise to vibrations of tube bundles requires a great deal of experimental insight. Accordingly, the prediction of the flow-induced vibration due to unsteady cross-flow can be greatly aided by semi-analytical models, in which some coefficients are determined experimentally. A laboratory test rig with an instrumented test bundle is constructed to measure the fluidelastic coefficients to be used in conjunction with the mathematical model derived in Part I of this paper. The test rig admits two different test bundles, namely, the inline-square and 45deg rotated-square tube arrays. Measurements were conducted to identify the flow-induced dynamic coefficients. The developed scheme was utilized in predicting the onset of flow-induced vibrations in two configurations of tube bundles, and results were examined in the light of Tubular Exchange Manufacturers Association (TEMA) predictions. The comparison demonstrated that TEMA guidelines are more conservative in the two configurations considered.

An Experimental Investigation of the Dynamics of a Loosely Supported Tube Array

2017 ◽  
Author(s):  
Amro Elhelaly ◽  
Marwan Hassan ◽  
Atef Mohany ◽  
Soha Moussa
Keyword(s):  
Experimental Investigation ◽  
Impact Force ◽  
Cross Flow ◽  
Open Loop ◽  
Diameter Ratio ◽  
Force Level ◽  
Steam Generators ◽  
Flow Induced Vibration ◽  
System Integrity ◽  
Tube Bundles

The integrity of tube bundles is very important especially when dealing with high-risk applications such as nuclear steam generators. A major issue to system integrity is the flow-induced vibration (FIV). FIV is manifested through several mechanisms including the most severe mechanism; fluidelastic instability (FEI). Tube vibration can be constrained by using tube supports. However, clearances between the tube and their support are required to allow for thermal expansion and for other manufacturing considerations. The clearance between tubes may allow frequent impact and friction between tube and support. This in turn may cause fatigue and wear at support and potential for catastrophic tube failure. This study aims to investigate the dynamics of loosely supported tube array subjected to cross-flow. The work is performed experimentally in an open-loop wind tunnel to address this issue. A loosely-supported single flexible tube in both triangle and square arrays subjected to cross-flow with a pitch-to-diameter ratio of 1.5 and 1.733, respectively were considered. The effect of the flow approach angle, as well as the support clearance on the tube response, are investigated. In addition, the parameters that affect tube wear such as impact force level are presented.

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