THESIS ABSTRACT (ENGLISH)
NAME: MUFATIU MUSILIU BELLO
TITLE: Experimental and Numerical Investigations of Flow-Accelerated Corrosion Downstream Orifices
MAJOR: MECHANICAL ENGINEERING
DATE: 8th May, 2012
Flow-Accelerated Corrosion (FAC) is a form of corrosion that affects carbon steel or low-alloy steel piping and fittings in power plants. Piping degradation due to FAC, especially downstream of control valves and restricting orifices, is considered to be one of the major safety and reliability problems facing aging power plants, where piping rupture occurs in high pressure systems. Accurate prediction of the highest FAC wear rate locations enables the mitigation of sudden and catastrophic failures, and the improvement of the plant capacity factor. The objective of the present study is to evaluate the effect of the local flow and mass transfer parameters on flow accelerated corrosion downstream of orifices. Orifice to pipe diameter ratios of 0.25, 0.5 and 0.74 were investigated numerically, under single phase flow conditions, by solving the continuity and momentum equations at Reynolds number of Re = 20,000. Laboratory experiments, using test sections made of hydrocal (CaSO4.½H2O) were carried out under both single and two phase flow conditions, in order to determine the surface wear pattern and validate the numerical results. The maximum mass transfer coefficient found to occur at approximately 1- 4 pipe diameters downstream of the orifice. This location was also found to correspond to the location of elevated turbulent kinetic energy generated within the flow separation vortices downstream of the orifice. The FAC wear rates were correlated with the turbulence kinetic energy and wall mass transfer in terms of Sherwood number. The current study provides FAC engineers in power plants with very useful information for better preparation of plant inspection scope.
MASTER OF SCIENCE DEGREE
KING FAHD UNIVERSITY OF PETROLEUM & MINERALS
Dhahran, Saudi Arabia
Table of Contents
Contents
Page
Acknowledgement………………………………………………………
iv
List of Tables……………………………………………………………….
vii
List of Figures……………………………………………………………..
viii
Abstract (English)……………………………………………………….
xii
Abstract (Arabic)…………………………………………………………
xiii
1.0 Introduction………………………………………………………….
1.1 Background…………………………………………………………..
1.2 Flow-Accelerated Corrosion (FAC)…………………………………
1
1
2
2.0 Motivation and Objectives……………………………………….
2.1 Motivation……………………………………………………………
2.2 Objectives…………………………………………………………….
5
5
5
3.0 Literature Review…………………………………………………….
3.1 Experimental Investigations………………………………………….
3.1.1 FAC In Single Phase Flows………………………………………
3.1.2 FAC In Two Phase Flows…………………………………………
3.2 Numerical Investigations…………………………………………….
3.2.1 Single Phase Flow Modelling For FAC
Prediction..………………………………………………………
3.2.2 Two Phase Flow Modelling For FAC
Prediction…………………………………………………………
3.2.3 Mass Transfer Modelling For FAC
Prediction………………………………………………………….
3.2.4 Flow and Mass Transfer Modelling……………………………….
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8
8
11
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15
19
21
4.0 MATHEMATICAL FORMULATION……………………………………..
4.1 Problem Statement…………………………………………………..
1.2 Governing Equations………………………………………………..
1.3 Mass Transfer Calculations…………………………………………..
1.4 Boundary Conditions………………………………………………..
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23
25
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28
2.0 Numerical Solution…………………………………………………
2.1 Grids Independence Study…………………………………………..
2.2 Model Validation…………………………………………………….
2.3 Numerical Results and Discussions………………………………….
5.3.1 Flow Field……………………………………………………….
5.3.2 Mass Transfer…………………………………………………
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31
31
37
37
48
3.0 Experimental Analysis……………………………………………
3.1 Materials…………………………………………………………….
3.2 Experimental Setup and Procedure…………………………………..
3.3 Measurement techniques…………………………………………….
3.4 Experimental Results and Discussions……………………………….
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71
4.0 Validation OF Results………………………………………………
4.1 Comparison of Numerical With Correlation…………………………
4.2 Comparison of Numerical Results With Single Phase Experimental Results………………………………………………………………
88
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89
5.0 CONCLUSION AND RECOMMENDATIONS……………………………
5.1 Conclusions…………………………………………………………..
5.2 Recommendations and Future Work…………………………………
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95
NOMENCLATURE………………………………………………………………
96
References……………………………………………………………………
98
Bello, M. (2018). EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF FLOW-ACCELERATED CORROSION DOWNSTREAM ORIFICES. Afribary. Retrieved from https://tracking.afribary.com/works/mufatiu-musiliu-bello-msc-thesis
Bello, Mufatiu "EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF FLOW-ACCELERATED CORROSION DOWNSTREAM ORIFICES" Afribary. Afribary, 18 Apr. 2018, https://tracking.afribary.com/works/mufatiu-musiliu-bello-msc-thesis. Accessed 12 Nov. 2024.
Bello, Mufatiu . "EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF FLOW-ACCELERATED CORROSION DOWNSTREAM ORIFICES". Afribary, Afribary, 18 Apr. 2018. Web. 12 Nov. 2024. < https://tracking.afribary.com/works/mufatiu-musiliu-bello-msc-thesis >.
Bello, Mufatiu . "EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF FLOW-ACCELERATED CORROSION DOWNSTREAM ORIFICES" Afribary (2018). Accessed November 12, 2024. https://tracking.afribary.com/works/mufatiu-musiliu-bello-msc-thesis