scholarly journals Experimental Study on Impact/Fretting Wear in Heat Exchanger Tubes

1987 ◽  
Vol 109 (3) ◽  
pp. 265-274 ◽  
Author(s):  
J. H. Cha ◽  
M. W. Wambsganss ◽  
J. A. Jendrzejczyk
Keyword(s):  
Heat Exchanger ◽  
Plate Thickness ◽  
Fretting Wear ◽  
304 Stainless Steel ◽  
Plate Interface ◽  
Wear Rates ◽  
Inconel 600 ◽  
Support Plate ◽  
Fluid Environment ◽  
Support Tube

The objective of this study is to provide qualitative impact/fretting wear information for heat exchanger tubes through the performance of a series of tests involving the pertinent parameters: force between the tube and its support; tube to support plate hole clearance; tube support plate thickness; preload; and tube vibration frequency. The characteristics of impact/fretting wear relative to material combinations and fluid environment were also investigated. The test apparatus consists of a cantilevered tube with a simulated tube support plate at the “free end.” Tube vibration is induced by an electromagnetic exciter to simulate the flow-induced tube motion occurring in a real heat exchanger at the tube/tube support plate interface. Tests are conducted in air, water, and oil, all at room temperature. Removable wear rings are attached to the tube free end and simulated support fixture. Wear ring materials include carbon steel, 304 stainless steel, Inconel 600 and brass. Wear is measured by a weight loss technique and wear rates are calculated and reported as functions of the various pertinent parameters. Based on the test results, general conclusions are drawn.

Fretting Wear of Heat Exchanger Tubes—Part II: Models

1979 ◽  
Vol 101 (4) ◽  
pp. 630-633 ◽  
Author(s):  
R. D. Blevins
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Relative Motion ◽  
Empirical Models ◽  
Fretting Wear ◽  
Support Plate

Conceptual and empirical models are developed for the fretting wear of heat exchanger tubes. The models based on the experimental data of Part I of this series and on the concept that fretting wear is the result of relative motion between the tube and the support plate.

Fretting Wear of Heat Exchanger Tubes—Part I: Experiments

1979 ◽  
Vol 101 (4) ◽  
pp. 625-629 ◽  
Author(s):  
R. D. Blevins
Keyword(s):  
Heat Exchanger ◽  
Empirical Model ◽  
Room Temperature ◽  
Fretting Wear ◽  
Support Plate ◽  
Air Atmosphere ◽  
The Mean

The results of a series of measurements made on the fretting wear of heat exchanger tubes and support plates at room temperature in a nitrogen/air atmosphere are presented. The fretting wear is shown to be a function of the amplitude and frequency of tube vibration as well as the gap between the tube and the support plate and the mean load supported by the tube. An empirical model is developed in Part II for predicting the fretting wear.

Non-Linear Time Domain Method to Predict Tube-to-Tube Support Plate Fretting Wear in Steam Generators

2006 ◽  
Author(s):  
J. A. Burgess ◽  
M. K. Au-Yang ◽  
C. K. Chandler
Keyword(s):  
Heat Exchanger ◽  
Time Domain ◽  
Time History ◽  
Fretting Wear ◽  
Design Stage ◽  
Superposition Method ◽  
Linear Interaction ◽  
Support Plate ◽  
Forcing Function ◽  
Non Linear

Fretting-wear of nuclear heat exchanger equipment is addressed at the design stage to demonstrate that the tube and tube support plate components will meet their design life. AREVA has developed a method to predict the progression of fretting-wear using a combination of the predicted work-rates determined from the non-linear interaction of the tube and tube support plates caused by turbulence-induced vibration and the forces associated with fluid-elastic instability. The wear rate is then computed based upon the work-rate and the experimentally determined wear coefficient of the material pair. This solution is performed with a time domain analysis using a time history modal superposition method. Time history forcing functions are first obtained by the inverse Fourier transform of the power spectral density function used in classical turbulence-induced vibration analysis. The fluid-structure coupling force, which is dependent on the cross-flow velocity, is linearly superimposed onto the turbulence forcing function. The tube responses are then computed by direct integration in the time domain. The results of the analysis show that the highest work-rates occur at the design tube-to-tube support plate clearance configuration and become progressively lower over the life of the heat exchanger. The work-rates and the turbulence-induced vibration response of the tube are computed at several mid-life time steps based upon the increased tube-to-tube support plate clearances resulting from the tube wear.

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.

Wear Characteristics of INCONEL 690 and INCONEL 600 in Elevated Temperature

2005 ◽  
Vol 297-300 ◽  
pp. 1424-1429 ◽  
Author(s):  
Sung Hoon Jeong ◽  
Young Ze Lee
Keyword(s):  
Wear Mechanisms ◽  
Nuclear Power ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Fretting Wear ◽  
Wear Characteristics ◽  
Inconel 600 ◽  
Wear Life ◽  
Inconel 690 ◽  
C 50

In this paper, the fretting wear characteristics of INCONEL 690 (I-690) and INCONEL 600 (I-600) was evaluated to verify the wear mechanism and the wear life. Because of the excellent corrosion-resistance of nickel-based alloy, those materials are used for steam generator tube in nuclear power plants. Sometimes the tubes are damaged due to small amplitude vibration, so called fretting wear. To verify the fretting wear mechanisms the wear experiment was carried with the crossed-cylinder wear tester, which used a cam to oscillate the specimen. The test was carried out at loads of 40N and 90N in elevated temperatures of water. The temperatures of water were 20°C, 50°C and 80°C. The increase of water temperature causes the oxidation of the contact area to be delayed, and the amount of wear on oxide layer to be reduced. The main wear mechanisms of fretting were abrasive wear and oxidation wear.

Fretting wear mechanisms of Zircaloy-4 and Inconel 600 contact in air

2001 ◽  
Vol 15 (9) ◽  
pp. 1274-1280 ◽  
Author(s):  
Tae-Hyung Kim ◽  
Seock-Sam Kim
Keyword(s):  
Wear Mechanisms ◽  
Fretting Wear ◽  
Inconel 600

Correlation of Support Impact Force and Fretting-Wear for a Heat Exchanger Tube

1984 ◽  
Vol 106 (1) ◽  
pp. 69-77 ◽  
Author(s):  
P. L. Ko ◽  
H. Basista
Keyword(s):  
Heat Exchanger ◽  
Impact Force ◽  
Computer Code ◽  
Oblique Impact ◽  
Dynamic Interaction ◽  
Fretting Wear ◽  
Heat Exchanger Tube ◽  
Dynamic Interactions ◽  
Realistic Assessment ◽  
Exchanger Tube

Flow-induced tube vibration can cause dynamic interactions between a tube and its supports. Both wear information and results from vibration analyses are needed to achieve a realistic assessment of long-term tube wear. Normal and oblique impact forces at the tube supports characterize dynamic interaction between tube and tube-support, and can be correlated to the rate of fretting-wear. A statistical analysis of the force signal provides an indication of the time distribution of various force levels during a vibration cycle. Different schemes for obtaining a weighted sum of these force levels were developed to account for changes in excitation levels, tube/support clearance, and the type of tube motion. With one of the schemes, the correlation to measured wear data was good. Therefore, fretting-wear can be estimated directly from the analytically predicted support impact force in a steam generator or heat exchanger tube. The effects of other support parameters, such as tube support land area, can be added to the empirical equation. A series of tests involving the three parameters mentioned were performed in room temperature water. Forces along two orthogonal axes at the support were recorded and analysed. The paper presents the results of these tests and shows the correlation between the wear results and the force functions. A computer code for predicting tube/support dynamic interaction is used to estimate wear damages from the experimental force-wear correlation.

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