|
|
|
| A NOVEL MODEL FOR PREDICTING FLOW ACCELERATED CORROSION RATE IN REDUCER |
| LU Xiaofeng, ZHU Xiaolei, LING Xiang |
| School of Mechanical and Power Engineering, Nanjing University of Technology, Nanjing 210009 |
|
|
|
|
Abstract A new prediction model was proposed to calculate the flow accelerated corrosion (FAC) rate in reducer, which was coupled the steady-state mass transfer model electrochemical theory and one-dimensional galvanic corrosion model. Firstly, the steady-state mass transfer model was used to obtain the distribution of concentration polarization current density and the concentration polarization corrosion potential of velocity extreme point near the wall of reducer. The galvanic corrosion current density was calculated by substituting the potential into one-dimensional galvanic corrosion model. The new model was employed to calculate the reducer; the results showed that the corrosion current density of large-end was larger two orders than that of small-end. Compared with the FAC rate calculated by the wall shear stress theory, presented by Efird and Cheng, or by purely steady-state mass transfer theory, the results obtained by the new model have good agreement with the practical situation which were counted 2000 pipe fittings in Taiwan nuclear power plant by Kuen Ting. The statistical result showed that the large-end of reducer appeared the maximum of reduction of thickness.
|
|
Received: 19 November 2010
|
|
|
|
Corresponding Authors:
LU Xiaofeng
E-mail: xflu@njut.edu.cn
|
| [1] Smith C L, Shah V N, Kao T, Apotolakis G. Incorporating aging effects into probabilistic risk models [R]. US Nuclear Regulatory Commission, NUREG/CR-5632, 2001[2] Shoji T, Lu Z, Takeda Y, Sato Y. Towards proactive materials degradation management in NPP-today and future [A], CD Proceedings of the 14th Asia Pacific Corrosion Control Conference (APCCC)[C]. Shanghai, 2006: 21-24[3] Chexal V K, Horowitz J, Dooley K B, et al. Flow-accelerated-corrosion in power plants [R]. Electric Power Research Institute, EPRI, TR-10061R1, 1981[4] Berge J P. Effect of chemistry on corrosion-erosion of steels in water and wet stream[A], Proceeding of 2nd Conference on Water Chemistry[C]. BNES, 1980[5] Wu P C. Erosion/corrosion induced pipe wall thinning in US nuclear power plants [R]. NUREG-1344, 1989[6] Zheng Y G, Liu C B. Research progress on modeling and numerical simulation of flow-accelerated-corrosion [J]. Corros. Sci. Prot. Technol., 2008, 20(6): 436-439 (郑玉贵, 刘春波.核电行业中流动促进腐蚀的模型和数值模拟研究进展[J].腐蚀科学与防护技术. 2008, 20(6): 436-439)[7] Guimaraes A C F. A new methodology for the study of FAC phenomenon based on a fuzzy rule system [J]. An. Nucl. Energy, 2003,30: 853-864[8] Fleming K N. Markov models for evaluating risk-informed in service inspection strategies for nuclear power plant piping systems [J]. Reliab. Eng. Syst. Saf., 2004, 83-27[9] Uchida S, Naitoh M, Uehara Y, et al. Evaluation methods for corrosion damage of components in cooling analysis of corrosion and flow dynamics (III)-evaluation of wall thinning rate with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis[J]. J. Nucl. Sci. Technol., 2009, 46(1): 31-40[10] Matsumura M. A case study of a pipe line burst in the Mihama Nuclear Power Plant [J]. Mater. Corros., 2006, 57(11):872-882[11] Song G L. Potential and current distributions of one-dimensional galvanic corrosion systems [J]. Corros. Sci., 2010,52: 455-480[12] Liu Z, Liu C B, Zheng Y G. Numerical simulation of flow-accelerated-corrosion of carbon steel in single liquid phase flow [J]. Nucl. Power Eng., 2009, 30: 48-53 (刘忠, 刘春波,郑玉贵. 碳钢在单相流中流动加速腐蚀的数值模拟[J]. 核动力工程, 2009,30: 48-53)[13] Hayduk W, Minhas B S. Correlation for prediction of molecular diffusivities in liquids [J]. Can. J. Chem. Eng., 1982,60(2): 295-299[14] Efird K D, Wright E J, Boros J A, et al. Correlation of steel corrosion in pipe flow with jet impingement and rotation cylinder tests [J]. Corros. Eng., 1993, 49(2): 992-1004[15] Zhang G A, Cheng Y F. Electrochemical characterization and computational fluid dynamics simulation of flow-accelerated-corrosion of X65 steel in a CO2-saturated oilfield formation water [J]. Corros. Sci., 2010: 52: 2716-2724[16] Kuen T, Yin P M. The evaluation of erosion corrosion problems of carbon steel piping in Taiwan PWR nuclear power plant [J]. Nucl. Eng. Des., 1999, 191: 231-243 |
| No Suggested Reading articles found! |
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
