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.

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.

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.

scholarly journals Experimental analysis and ANN prediction on performances of finned oval-tube heat exchanger under different air inlet angles with limited experimental data

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 968-980
Author(s):  
Xueping Du ◽  
Zhijie Chen ◽  
Qi Meng ◽  
Yang Song
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Correlation Equation ◽  
Tube Heat Exchanger ◽  
Flow Friction ◽  
Air Inlet ◽  
Comparison Results ◽  
Wide Range ◽  
Oval Tube

Abstract A high accuracy of experimental correlations on the heat transfer and flow friction is always expected to calculate the unknown cases according to the limited experimental data from a heat exchanger experiment. However, certain errors will occur during the data processing by the traditional methods to obtain the experimental correlations for the heat transfer and friction. A dimensionless experimental correlation equation including angles is proposed to make the correlation have a wide range of applicability. Then, the artificial neural networks (ANNs) are used to predict the heat transfer and flow friction performances of a finned oval-tube heat exchanger under four different air inlet angles with limited experimental data. The comparison results of ANN prediction with experimental correlations show that the errors from the ANN prediction are smaller than those from the classical correlations. The data of the four air inlet angles fitted separately have higher precisions than those fitted together. It is demonstrated that the ANN approach is more useful than experimental correlations to predict the heat transfer and flow resistance characteristics for unknown cases of heat exchangers. The results can provide theoretical support for the application of the ANN used in the finned oval-tube heat exchanger performance prediction.

scholarly journals Numerical Analysis of Liquid–Liquid Heat Pipe Heat Exchanger Based on a Novel Model

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 589
Author(s):  
Qilu Chen ◽  
Yutao Shi ◽  
Zhi Zhuang ◽  
Li Weng ◽  
Chengjun Xu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Heat Exchanger ◽  
Heat Pipe ◽  
Temperature Change ◽  
Current Model ◽  
Change Trend ◽  
Liquid Heat ◽  
Novel Model ◽  
Pipe Heat ◽  
Vapor Temperature

Heat pipe heat exchangers (HPHEXs) are widely used in various industries. In this paper, a novel model of a liquid–liquid heat pipe heat exchanger in a countercurrent manner is established by considering the evaporation and condensation thermal resistances inside the heat pipes (HPs). The discrete method is added to the HPHEX model to determine the thermal resistances of the HPs and the temperature change trend of the heat transfer fluid in the HPHEX. The established model is verified by the HPHEX structure and experimental data in the existing literature and demonstrates numerical results that agree with the experimental data to within a 5% error. With the current model, the investigation compares the effectiveness and minimum vapor temperature of the HPHEX with three types of HP diameters, different mass flow rates, and different H* values. For HPs with a diameter of 36 mm, the effectiveness of each is improved by about 0.018 to 0.029 compared to HPs with a diameter of 28 mm. The results show that the current model can predict the temperature change trend of the HPHEX well; in addition, the effects of different structures on the effectiveness and minimum vapor temperature are obtained, which improve the performance of the HPHEX.

Composite Fretting Wear of Aluminum Alloy

2007 ◽  
Vol 353-358 ◽  
pp. 868-873 ◽  
Author(s):  
Min Hao Zhu ◽  
Zhong Rong Zhou
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Relative Motion ◽  
Wear Mechanism ◽  
Normal Force ◽  
Fretting Wear ◽  
Test Results ◽  
Contact Configuration ◽  
Inclined Angle ◽  
Flat Contact

A complex relative motion of fretting combined by dual motions of radial and tangential fretting was achieved on a modified fretting tester. The composite fretting motion was induced by the action of an oscillating normal force in a sphere-on-inclined flat contact (52100 steel ball against 2091 aluminum alloy). Two types of inclined angles (45° and 60°) were used in the tests. Variations of veridical force vs displacement have been recorded and analyzed as a function of cycles. Effects of the cyclic normal force and the inclined angle were discussed. The test results showed that wear, cracking and plastic deformation accumulation with a strong dissymmetry in damage morphology was observed. A transformation of fretting mode from composite to radial fretting mode occurred due to a strong modification at local contact configuration. As a conclusion, a physical model for wear mechanism of composite fretting was presented.

Characterization of fretting wear experiments on spline couplings by principal component analysis

2016 ◽  
Vol 231 (7) ◽  
pp. 860-868 ◽  
Author(s):  
Waqar Qureshi ◽  
Francesca Cura ◽  
Andrea Mura
Keyword(s):  
Experimental Data ◽  
Principal Component Analysis ◽  
Principal Component ◽  
Component Analysis ◽  
Fretting Wear ◽  
Aircraft Industry ◽  
Surface Movement ◽  
Noisy Measurements ◽  
Quasi Static Process

Fretting wear is a quasi-static process in which repeated relative surface movement of components results in wear and fatigue. Fretting wear is quite significant in the case of spline couplings which are frequently used in the aircraft industry to transfer torque and power. Fretting wear depends on materials, pressure distribution, torque, rotational speeds, lubrication, surface finish, misalignment between spline shafts, etc. The presence of so many factors makes it difficult to conduct experiments for better models of fretting wear and it is the case whenever a mathematical model is sought from experimental data which is prone to noisy measurements, outliers and redundant variables. This work develops a principal component analysis based method, using a criterion which is insensitive to outliers, to realize a better design and interpret experiments on fretting wear. The proposed method can be extended to other cases too.

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.

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