Damping of Heat Exchanger Tubes in Liquids: Review and Design Guidelines

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
M. J. Pettigrew ◽  
R. J. Rogers ◽  
F. Axisa
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Energy Dissipation ◽  
Design Guidelines ◽  
Squeeze Film ◽  
Viscous Damping ◽  
Shell Side ◽  
Squeeze Film Damping ◽  
Dissipation Mechanism ◽  
Semi Empirical

This paper addresses the question of damping of multispan heat exchanger tubes with liquids (mostly water) on the shell side. The different energy dissipation mechanisms that contribute to damping are investigated. The available experimental data from the literature and from our own measurements are reviewed and analyzed. Three important energy dissipation mechanisms emerge. These are viscous damping between the tube and liquid, squeeze-film damping in the clearance between the tube, and support and friction damping at the support. Viscous damping only accounts for approximately 25% of the total damping of a typical tube. Thus, about 75% of the damping energy is dissipated at the support. Squeeze-film damping appears to be the most important energy dissipation mechanism. Squeeze-film damping is related to the support width and is inversely proportional to the tube frequency. Damping is formulated in terms of tube and tube-support parameters. Semi-empirical formulations for damping of heat exchanger tubes in liquids are recommended for design purposes.

Vibration Damping in Multispan Heat Exchanger Tubes

1998 ◽  
Vol 120 (3) ◽  
pp. 283-289 ◽  
Author(s):  
C. E. Taylor ◽  
M. J. Pettigrew ◽  
T. J. Dickinson ◽  
I. G. Currie ◽  
P. Vidalou
Keyword(s):  
Heat Exchanger ◽  
Fretting Wear ◽  
Resonant Peak ◽  
Effect Of Temperature ◽  
Squeeze Film ◽  
Fluid Viscosity ◽  
Viscous Damping ◽  
Friction Damping ◽  
Flow Induced Vibration ◽  
Squeeze Film Damping

Heat exchanger tubes can be damaged or fail if subjected to excessive flow-induced vibration, either from fatigue or fretting-wear. Good heat exchanger design requires that the designer understands and accounts for the vibration mechanisms that might occur, such as vortex shedding, turbulent excitation or fluidelastic instability. To incorporate these phenomena into a flow-induced vibration analysis of a heat exchanger requires information about damping. Damping in multispan heat exchanger tubes largely consists of three components: viscous damping along the tube, and friction and squeeze-film damping at the supports. Unlike viscous damping, squeeze-film damping and friction damping are poorly understood and difficult to measure. In addition, the effect of temperature-dependent fluid viscosity on tube damping has not been verified. To investigate these problems, a single vertical heat exchanger tube with multiple spans was excited by random vibration. Tests were conducted in air and in water at three different temperatures (25, 60, and 90°C). At room temperature, tests were carried out at five different preloads. Frequency response spectra and resonant peak-fitted damping ratios were calculated for all tests. Energy dissipation rates at the supports and the rate of excitation energy input were also measured. Results indicate that damping does not change over the range of temperatures tested and friction damping is very dependent on preload.

Damping of Heat Exchanger Tubes in Two-Phase Flow: Review and Design Guidelines

2004 ◽  
Vol 126 (4) ◽  
pp. 523-533 ◽  
Author(s):  
M. J. Pettigrew ◽  
C. E. Taylor
Keyword(s):  
Heat Exchanger ◽  
Two Phase Flow ◽  
Cross Flow ◽  
Design Guidelines ◽  
Phase Flow ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Design Guideline ◽  
Fluid Properties ◽  
Semi Empirical

Two-phase flow exists in many shell-and-tube heat exchangers such as condensers, evaporators, and nuclear steam generators. Some knowledge on tube damping mechanisms is required to avoid flow-induced vibration problems. This paper outlines the development of a semi-empirical model to formulate damping of heat exchanger tube bundles in two-phase cross flow. The formulation is based on information available in the literature and on the results of recently completed experiments. The compilation of a database and the formulation of a design guideline are outlined in this paper. The effects of several parameters such as flow velocity, void fraction, confinement, flow regime and fluid properties are discussed. These parameters are taken into consideration in the formulation of a practical design guideline.

Squeeze Film Damping Models Compared With Tests on Microsystems

2006 ◽  
Author(s):  
Hartono (Anton) Sumali ◽  
David S. Epp
Keyword(s):  
Experimental Data ◽  
Damping Ratio ◽  
Laser Doppler Vibrometer ◽  
Squeeze Film ◽  
Parallel Plates ◽  
Squeeze Film Damping ◽  
Wide Range ◽  
Oscillation Frequencies ◽  
Oscillating Plate ◽  
The Continuum

This paper compares three models for computing forces caused by gas film squeezed between parallel plates. The models are used to calculate damping forces on an oscillating plate at different oscillation frequencies. The damping forces are then used to calculate nondimensional damping ratios. The damping ratios are used in making comparisons among the models and with experimental data. The experiment used an oscillating MEMS plate suspended by folded springs. The substrate (base) was shaken with a piezoelectric transducer. The plate vibrated as a result, especially at the resonant frequency. The velocities of the suspended plate and of the substrate were measured with a laser Doppler vibrometer and a microscope. Experimental modal analysis gave the damping ratio. To achieve a wide range of squeeze numbers, the experiment was repeated under several different pressures. The measurement was also repeated on an array of plates. Experimental data indicate that, for atmospheric and higher pressures, squeeze-film damping forces can be modeled accurately with a very simple model. For lower pressures in the continuum regime, a more complete model by Veijola (2004) predicts the damping ratio very well.

scholarly journals Experimental Validation of a Squeeze-Film Damping Model Based on the Direct Simulation Monte Carlo Method

2007 ◽  
Author(s):  
Hartono Sumali ◽  
David S. Epp ◽  
John R. Torczynski ◽  
Michael A. Gallis
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Experimental Validation ◽  
Tangential Velocity ◽  
Direct Simulation Monte Carlo ◽  
Squeeze Film ◽  
Direct Simulation ◽  
Parallel Plates ◽  
Squeeze Film Damping ◽  
Simulation Monte Carlo

A model for computing the force from a gas film squeezed between parallel plates was recently developed using Direct Simulation Monte Carlo simulations in conjunction with the classical Reynolds equation. This paper compares predictions from that model with experimental data. The experimental validation used an almost rectangular MEMS oscillating plate with piezoelectric base excitation. The velocities of the suspended plate and of the substrate were measured with a laser Doppler vibrometer and a microscope. Experimental modal analysis yielded the damping ratio of twelve test structures for several different gas pressures. Small perforation holes in the plates did not alter the squeeze-film damping substantially. These experimental data suggest that the model predicts squeeze-film damping forces accurately. From this comparison, it is seen that these structures have a tangential-velocity accommodation coefficient close to unity.

A simple expression for fluid inertia force acting on micro-plates undergoing squeeze film damping

2010 ◽  
Vol 467 (2126) ◽  
pp. 522-536 ◽  
Author(s):  
Shujuan Huang ◽  
Diana-Andra Borca-Tasciuc ◽  
John A. Tichy
Keyword(s):  
Separation Distance ◽  
Simple Expression ◽  
Squeeze Film ◽  
Inertia Force ◽  
Viscous Damping ◽  
Fluid Inertia ◽  
Inertia Effects ◽  
Viscous Forces ◽  
Squeeze Film Damping ◽  
Micro Plates

Squeeze film damping in systems employing micro-plates parallel to a substrate and undergoing small normal vibrations is theoretically investigated. In high-density fluids, inertia forces may play a significant role affecting the dynamic response of such systems. Previous models of squeeze film damping taking inertia into account do not clearly isolate this effect from viscous damping. Therefore, currently, there is no simple way to distinguish between these two hydrodynamic effects. This paper presents a simple solution for the hydrodynamic force acting on a plate vibrating in an incompressible fluid, with distinctive terms describing inertia and viscous damping. Similar to the damping constant describing viscous losses, an inertia constant, given by ρL 3 W / h (where ρ is fluid density, L and W are plate length and width, respectively, and h is separation distance), may be used to accurately calculate fluid inertia for small oscillation Reynolds numbers. In contrast with viscous forces that suppress the amplitude of the oscillation, it is found that fluid inertia acts as an added mass, shifting the natural frequency of the system to a lower range while having little effect on the amplitude. Dimensionless parameters describing the relative importance of viscous and inertia effects also emerge from the analysis.

Semi-Analytical Calculation of the Inlet Zone Performance of Ideal Shell and Tube Heat Exchangers

2010 ◽  
Author(s):  
K. Mohammadi ◽  
W. Heidemann ◽  
H. Mu¨ller-Steinhagen
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Numerical Data ◽  
Shell Side ◽  
Tube Heat Exchanger ◽  
Performance Factor ◽  
Shell And Tube ◽  
Inlet Zone

A semi-analytical model is presented for the evaluation of the performance factor of the inlet zone of an E type shell and tube heat exchanger without leakage flows. The performance factor is defined as the ratio of dimensionless heat transfer coefficients and pressure drops of both vertical and horizontal baffle orientation and therefore facilitates the decision between horizontal and vertical baffle orientation of shell and tube heat exchangers. The model allows the calculation of the performance factor of the inlet zone as a function of the baffle cut, the shell-side Reynolds number at the inlet nozzle and the Prandtl number of the shell-side fluid. The application of the model requires the knowledge of the performance factor of water at baffle cut equal to 24% of the shell inside diameter. For the development of the model a numerical data basis is used due to the lack of experimental data for shell and tube heat exchangers with different baffle orientations. The numerical data are obtained from CFD calculations for steady state conditions within a segmentally baffled shell and tube heat exchanger following the TEMA standards. Air, water and engine oil with Prandtl numbers in the range of 0.7 to 206 are used as shell-side fluids. The semi-analytical model introduced for the performance factor predicts the CFD results with a relative absolute error less than 5%. The presented model has to be validated with further experimental data and/or numerical results which explain the effect of baffle orientation on the shell-side heat transfer coefficient and pressure drop in order to check the general applicability.

Acoustic Resonance in Heat Exchanger Tube Bundles—Part II: Prediction and Suppression of Resonance

1987 ◽  
Vol 109 (3) ◽  
pp. 282-288 ◽  
Author(s):  
R. D. Blevins ◽  
M. M. Bressler
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Vortex Shedding ◽  
Empirical Model ◽  
Acoustic Resonance ◽  
Heat Exchanger Tube ◽  
Tube Bundles ◽  
Semi Empirical ◽  
Exchanger Tube

In the first part of this series, experimental data were presented which suggest that the acoustic resonance in heat exchanger tube bundles is tied to periodic vortex shedding from the tubes. In this paper, a semi-empirical model for predicting the onset of resonance is developed. This model is compared with experimental data and other models from the literature. Methods of suppressing the resonance are developed and experimental data on their effectiveness are presented.

A Novel Expression for the Effective Viscosity to Model Squeeze-Film Damping at Low Pressure

2013 ◽  
Vol 390 ◽  
pp. 76-80 ◽  
Author(s):  
Maria F. Pantano ◽  
Salvatore Nigro ◽  
Franco Furgiuele ◽  
Leonardo Pagnotta
Keyword(s):  
Experimental Data ◽  
Effective Viscosity ◽  
Squeeze Film ◽  
Navier Stokes ◽  
Fluid Viscosity ◽  
The Novel ◽  
Mems Devices ◽  
Navier Stokes Equation ◽  
Experimental Procedure ◽  
Squeeze Film Damping

The Navier-Stokes equation is currentlyconsidered for modelling of squeeze-film damping in MEMS devices, also when the fluid flow associated to it is rarefied.In order to include rarefaction effects in such equation, a common approach consists of replacing the ordinary fluid viscosity with a scaled quantity, known as effective viscosity.The literature offers different expressions for the effective viscosity as a function of the Knudsen number (Kn). Such expressions were shown to work well whenKn<1, but theyresulted to be lessaccurate in case ofKn>1. In this paper a new expression is proposed to evaluate the effective viscosity for 1<Kn<40with increased reliability. Such anexpression was derivedfrom an optimized numerical-experimental procedure,developed in MATLAB® environment, using a finite element code and experimental data extracted from the literature. A comparison is finally reported and discussed between the results, in terms of damping coefficient, obtained considering previously reported effective viscosity expressions and the novel one,with reference to different squeeze film damping layouts, for which experimental data are already available.

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