Partial Admission Effects on the Stability of a Heat Exchanger Tube Array

1988 ◽  
Vol 110 (2) ◽  
pp. 194-198 ◽  
Author(s):  
L. F. Waring ◽  
D. S. Weaver
Keyword(s):  
Heat Exchanger ◽  
Elastic Stability ◽  
Uniform Flow ◽  
Heat Exchanger Tube ◽  
Tube Arrays ◽  
Partial Admission ◽  
Theoretical Predictions ◽  
Pitch Ratio ◽  
The Stability ◽  
Exchanger Tube

An experimental study is reported of the effects of partial admission on the fluid elastic stability of a heat exchanger tube array. The array geometry was a parallel triangular configuration with a pitch ratio of 1.47. Tests were conducted in a wind tunnel with uniform flow over from 33 to 100 percent of single span tubes. In these experiments, the flow location was also varied from center-span to the end supports. Additionally, tests were conducted with uniform flow over one span of two and three-span tube arrays. These results are compared with theoretical predictions.

Spanwise Correlation of Surface Pressure Fluctuations in Heat Exchanger Tube Arrays

2010 ◽  
Author(s):  
John Mahon ◽  
Paul Cheeran ◽  
Craig Meskell
Keyword(s):  
Heat Exchanger ◽  
Surface Pressure ◽  
Pressure Fluctuations ◽  
Cross Flow ◽  
Fretting Wear ◽  
Heat Exchanger Tube ◽  
Tube Arrays ◽  
Pitch Ratio ◽  
Excitation Mechanisms ◽  
Exchanger Tube

An experimental study of the surface spanwise pressure on a cylinder in the third row of two normal triangular tube arrays (P/d = 1.32 and 1.58) with air cross flow has been conducted. A range of flow velocities were examined. The correlation of surface pressure fluctuations due to various vibration excitation mechanisms along the span of heat exchanger tubes has been assessed. The turbulent buffeting is found to be uncorrelated along the span which is consistent with generally accepted assumptions in previous studies. Vortex shedding and acoustic resonances were well correlated along the span of the cylinder, with correlations lengths approaching the entire length of the cylinder. Jet switching was observed in the pitch ratio of 1.58 and was found to be correlated along the cylinder, although the spatial behaviour is complex. This result suggests that the excitation force used in fretting wear models may need to be updated to include jet switching in the calculation.

Two-Phase Flow-Induced Vibration of Parallel Triangular Tube Arrays With Asymmetric Support Stiffness

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Paul Feenstra ◽  
David S. Weaver ◽  
Tomomichi Nakamura
Keyword(s):  
Two Phase Flow ◽  
Cross Flow ◽  
Phase Flow ◽  
Heat Exchanger Tube ◽  
Flow Induced Vibration ◽  
Two Phase ◽  
Tube Arrays ◽  
Tube Bundles ◽  
Pitch Ratio ◽  
Exchanger Tube

Laboratory experiments were conducted to determine the flow-induced vibration response and fluidelastic instability threshold of model heat exchanger tube bundles subjected to a cross-flow of refrigerant 11. Tube bundles were specially built with tubes cantilever-mounted on rectangular brass support bars so that the stiffness in the streamwise direction was about double that in the transverse direction. This was designed to simulate the tube dynamics in the U-bend region of a recirculating-type nuclear steam generator. Three model tube bundles were studied, one with a pitch ratio of 1.49 and two with a smaller pitch ratio of 1.33. The primary intent of the research was to improve our understanding of the flow-induced vibrations of heat exchanger tube arrays subjected to two-phase cross-flow. Of particular concern was to compare the effect of the asymmetric stiffness on the fluidelastic stability threshold with that of axisymmetric stiffness arrays tested most prominently in literature. The experimental results are analyzed and compared with existing data from literature using various definitions of two-phase fluid parameters. The fluidelastic stability thresholds of the present study agree well with results from previous studies for single-phase flow. In two-phase flow, the comparison of the stability data depends on the definition of two-phase flow velocity.

A Comparative Overview of Marine Risers and Heat Exchanger Tube Banks

1991 ◽  
Vol 113 (1) ◽  
pp. 30-36
Author(s):  
M. M. Zdravkovich
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Design Guidelines ◽  
Heat Exchanger Tube ◽  
Marine Risers ◽  
Tube Arrays ◽  
Flow Induced Vibrations ◽  
Satellite Clusters ◽  
Tube Banks ◽  
Exchanger Tube

This is neither an original paper nor a review, but a comparative overview of two seemingly unrelated engineering fields. There are some similarities and strong dissimilarities between multipipe risers and tube arrays employed in heat exchangers. For example, square arrays are used in both, whereas “satellite” clusters cannot be found in heat exchangers. The extensive research on flow-induced vibrations in heat exchanger arrays reveals several mechanisms of excitation and sustenance of tube vibration. Some of the mechanisms identified for tube arrays may be relevant for marine risers. The main object of this comparative overview is to compile and discuss heat exchanger data which may be applicable to marine risers. Design guidelines are specified for satellite clusters.

Effect of nonlinear cladding stiffness on the stability and Hopf bifurcation of a heat-exchanger tube subject to cross-flow

Meccanica ◽  
2020 ◽  
Vol 55 (1) ◽  
pp. 49-68
Author(s):  
Varun Vourganti ◽  
Ajinkya Desai ◽  
Surya Samukham ◽  
C. P. Vyasarayani
Keyword(s):  
Heat Exchanger ◽  
Hopf Bifurcation ◽  
Cross Flow ◽  
Heat Exchanger Tube ◽  
The Stability ◽  
Exchanger Tube

Prediction of Acoustic Vibration in Steam Generator and Heat Exchanger Tube Banks

1996 ◽  
Vol 118 (2) ◽  
pp. 221-236 ◽  
Author(s):  
F. L. Eisinger ◽  
J. T. Francis ◽  
R. E. Sullivan
Keyword(s):  
Heat Exchanger ◽  
Steam Generator ◽  
Acoustic Vibration ◽  
Heat Exchanger Tube ◽  
Acoustic Parameters ◽  
Transverse Acoustic ◽  
Theoretical Predictions ◽  
Tube Banks ◽  
Service Data ◽  
Exchanger Tube

Criteria are formulated for the development of acoustic vibration in transverse acoustic modes in steam generator tube banks, based on flow and acoustic parameters. Theoretical predictions are validated against available in-service data for nonvibrating and vibrating tube banks and published laboratory experimental data. The criteria can be used for the prediction of acoustic vibration in steam generator and heat exchanger tube banks both, in-line and staggered.

scholarly journals Analysis and Implementation of Thermal Heat Exchanger Tube Performance with Helically Pierced Twisted Tape Inserts Using ANFIS Model

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Faisal Altarazi ◽  
Sunil Kumar ◽  
Gaurav Gupta ◽  
Muhammad Gulzar ◽  
Yaé Ulrich Gaba ◽  
...  
Keyword(s):  
Heat Exchanger ◽  
System Modeling ◽  
Diameter Ratio ◽  
Twisted Tape ◽  
Heat Exchanger Tube ◽  
Anfis Model ◽  
Inference System ◽  
Relative Pitch ◽  
Pitch Ratio ◽  
Exchanger Tube

The present work used ANFIS, an adaptive neuro-fuzzy inference system modeling to analyze the effect of the variable parameters of helically pierced twisted tape inserts on the Nusselt number, friction factor, and thermo-hydraulic heat exchanger tube performance. The experimental data utilized for ANFIS modeling considered a diameter ratio ranging from 0.57 to 0.80, a relative pitch ratio ranging from 0.046 to 0.107, a perforation index ranging from 5% to 20% as variable twisted tape parameters and flow parameters. The Reynolds number varies from 4000 to 30000. The analysis showed that the maximum thermo-hydraulic performance was obtained at a diameter ratio of 0.65, a relative pitch ratio of 0.085, and a perforation index equal to 10%. The result predicts that the ANFIS model and experimental results are in good agreement as they have only ±0.53% deviations.

Fluidelastic Vibration of Heat Exchanger Tube Arrays

1978 ◽  
Vol 100 (2) ◽  
pp. 347-353 ◽  
Author(s):  
H. J. Connors
Keyword(s):  
Heat Exchanger ◽  
Flow Velocity ◽  
Cross Flow ◽  
Test Results ◽  
Excitation Mechanism ◽  
Heat Exchanger Tube ◽  
Flow Test ◽  
Tube Arrays ◽  
Instability Constant ◽  
Exchanger Tube

A basic fluidelastic excitation mechanism, of a type reported in an earlier paper, causes large whirling vibrations of tubes in model arrays when the flow velocity exceeds a critical value. The critical velocity is U = βfnDmoδn/ρoD2 where β, the threshold instability constant is a function of the tube pattern and spacing. Threshold instability constants are given that were obtained from wind tunnel and water tunnel tests on multirow tube arrays in uniform cross flow. Test results are discussed that demonstrate the effects of spanwise variations in flow velocity on fluidelastic whirling for both straight tubes and U-tubes. Design methods are provided for predicting the onset of fluidelastic whirling of heat exchanger tubes on multiple supports when spanwise variations in the cross flow exist.

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