INTERNAL SURFACE PIPE ROUGHNESS CLASSIFICATION: AN ACOUSTIC EMISSIONS APPROACH ARIF JOHARI B MAT

Transcription

1 INTERNAL SURFACE PIPE ROUGHNESS CLASSIFICATION: AN ACOUSTIC EMISSIONS APPROACH ARIF JOHARI B MAT ALI@SALIM Thesis submitted in fulfillment of the requirements for the award of the degree of Bachelor of Mechanical Engineering Faculty of Mechanical Engineering UNIVERSITI MALAYSIA PAHANG NOVEMBER 2009

2 ii SUPERVISOR S DECLARATION I hereby declare that I have checked this project and in my opinion, this project is adequate in terms of scope and quality for the award of the degree of Bachelor of Mechanical Engineering. Signature Name of Supervisor: Mr. Mohd Hafizi b Zohari Position: Supervisor Date: November 2009

3 iii STUDENT S DECLARATION I hereby declare that the work in this project is my own except for quotations and summaries which have been duly acknowledged. The project has not been accepted for any degree and is not concurrently submitted for award of other degree. Signature Name: Arif Johari B Mat Ali@Salim ID Number: MA06075 Date: November 2009

4 iv I humbly dedicated this thesis to my lovely mom and late father, Aminah@Saidah Bt Ali and MatAli@Salim B Abdul Rahman and to all my beloved families who always trust me, love me and had been a great source of support and motivation.

5 v ACKNOWLEDGEMENT Alhamdulillah, thanks to Allah s.w.t for giving me strength in finishing this thesis within time given without any unsolved difficulties. The existence of this thesis is used to indicate that the journey of the study in obtaining my Bachelor Degree in Mechanical Engineering was going to complete soon. I have been accompanied and supported by many people both direct and indirectly during this thesis phase. It is a pleasant opportunity for me to express my gratitude for all of them now. Bundle of thanks you to my supervisor, Mr. Mohd Hafizi b Zohari for his great patient, helps and efforts to explain things clearly. He provided encouragements and contributes me lots of good ideas during the testing and thesis writing period. I would have been lost without his guidance and support. Besides, special thanks were dedicated those lecturers and lab instructor who lent their hands and shared their precious experiences with me. I am also indebted with the support of family and friends of mine. They accompanied me going through the up and down. Interdependence is certainly more valuable than independences.

6 vi ABSTRACT This project was carried out as a study of internal surface pipe roughness classification using single channel Acoustic Emissions (AE) technique. The objectives of this project are to detect Acoustic Emission (AE) signal from internal surface pipe and to classify smooth or rough of internal surface pipe using Acoustic Emission (AE). A test rig consists of the pipe with smooth internal surface and the pipe with rough internal surface using circumferential of a galvanized steel pipe used to run this experiment. Flow of water inside the pipe was controlled by a valve. The signal was captured using AE sensor with the help of Acoustic Emission Detector software. For all pipe conditions, the values of hits, counts and RMS (average, maximum and minimum) were recorded and analyzed. All the values recorded were compared between the internal smooth pipe and internal rough pipe (90 and 360 opening valve). The results were gained from 10 marked points each for both pipe conditions. The result show that the different value of AE parameter between high flow rate (360 opening valve) and low flow rate (90 opening valve) for smooth pipe is greater than rough pipe. The total of RMS value was plotted for each flow rate and surface pipe roughness at each point. Based on Bangi number (AB) the value for rough pipe is 1.75 and below, meanwhile for smooth pipe is 1.75 and above. This value can be used for the classification of internal surface pipe roughness.

7 vii ABSTRAK Projek ini dijalankan sebagai satu kajian tentang pengelasan permukaan dalaman menggunakan teknik pancaran akustik (AE) satu siaran. Objektif projek ini adalah untuk mengesan isyarat pancaran akustik daripada permukaan dalaman paip dan membuat pengelasan bahagian dalaman paip samada permukaan licin atau kasar menggunakn teknik pancaran akustik (AE). Satu rig ujikaji terdiri daripada permukaan paip licin dan permukaan paip kasar besi galvani berlilitan bulat telah digunakan untuk menjalankan eksperimen ini. Aliran air di dalam paip dikawal oleh injap. Isyarat telah dicerap dengan menggunakan penderia AE dengan bantuan paparan dari perisian Acoustic Emission Detector Untuk semua keadaan paip, nilai-nilai hits, counts dan RMS (purata, maksimum dan minimum) telah direkod dan dianalisis. Semua nilai yang direkod telah dibandingkan antara paip permukaan licin dan paip permukaan kasar (injap bukaan 90 dan injap bukaan 360 ). Keputusan diperoleh daripada 10 titik yang ditanda pada kedua-dua keadaan paip. Keputusan menunjukkan bahawa perbezaan nilai parameter AE antara aliran berkadar tinggi (injap bukaan 360 ) dan berkadar rendah (injap bukaan 90 ) bagi paip permukaan licin adalah lebih tinggi berbanding paip permukaan kasar. Jumlah RMS diplot bagi setiap kadar aliran dan jenis permukaan paip pada setiap titik. Berdasarkan kepada Angka Bangi (AB) nilai untuk paip permukaan kasar ialah 1.75 ke bawah manakala nilai untuk paip permukaan licin ialah 1.75 ke atas. Nilai ini boleh digunakan untuk mengelaskan kekasaran permukaan dalaman paip.

8 viii TABLE OF CONTENTS Page SUPERVISOR S DECLARATION STUDENT S DECLARATION ACKNOWLEDGEMENTS ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF SYMBOLS LIST OF ABBREVIATIONS ii iii v vi vii viii xi xii xiv xvi CHAPTER 1 INTRODUCTION 1.1 Introduction Objectives Scope Study Important of the Study 3 CHAPTER 2 LITERATURE REVIEW 2.1 Flow Analysis In a Circular Pipe Acoustic Emission (AE) Method A Brief History of Acoustic Emission (AE) Acoustic Emission Signals Type of Acoustic Emission (AE) Parameter Of Acoustic Emission (AE) Signal Root Means Square (RMS) Frequency analysis Crest factor analysis Kurtosis analysis 14

9 ix Counts Acoustic Emission (AE) in Pipes Distress pipes Critical pipes Whole pipes Construction zone The Advantages of Acoustic Emission (AE) Application of Acoustic Emission Corrosion Types of corrosion General corrosion Galvanic corrosion Intergranular corrosion Pitting corrosion Crevice corrosion Review Study about Acoustic Emission (AE) Testing 22 CHAPTER 3 METHODOLOGY 3.1 Introduction Flowchart Gantt Chart FYP 1 and FYP Test Rig And Tools Preparation Hardware Architecture Details Specification Test Rig Hydraulic Bench Acoustic Emission System Test s Procedure Reading Data 39

10 x CHAPTER 4 RESULTS AND DISCUSSION 4.1 Introduction Test Result and Discussion Fluid flow through smooth pipe with high and low flow 44 rate Fluid flow through rough pipe with high and low flow 45 rate High flow rate fluid flow in smooth pipe and rough pipe Low flow rate fluid flow in smooth pipe and rough pipe Average RMS values for smooth and rough pipe Bangi Number 49 CHAPTER 5 CONCLUSION AND RECOMMENDATIONS 5.1 Conclusion Recommendation 59 REFERENCES 61 APPENDICES 57 A1 Table data of rough surface pipe 63 A2 Point of Sensor versus 90 opened valve (rough pipe) 64 A3 Point of Sensor versus 360 opened valve (rough pipe) 65 A4 RMS value for each valve opening (rough pipe) 66 B1 Table data of smooth surface pipe 67 B2 Point of Sensor versus 90 opened valve (smooth pipe) 68 B3 Point of Sensor versus 360 opened valve (smooth pipe) 69 B4 RMS value for each valve opening (smooth pipe) 70 C1 Acoustic Emission Detector-2000V Rough Pipe,Point 10, C2 Acoustic Emission Detector-2000V Rough Pipe,Point 10, C3 Acoustic Emission Detector-2000V Smooth Pipe,Point 10, C4 Acoustic Emission Detector-2000V Smooth Pipe,Point 10,

11 xi LIST OF TABLES Table No. Title Page 2.1 Internal roughness (e) of common pipe materials Value of flow rate in several valve opening Average value of RMS for smooth inner surface Average value of RMS for rough inner surface Bangi number values for each point Description of each point of surface roughness Result of the analysis between the different type of pipe and flow 59 rate 5.2 Bangi number (AB) for rough and smooth pipe 59

12 xii LIST OF FIGURES Figure No. Title Page 2.1 Laminar and Turbulent flow The source of acoustic emission signal Burst signal Continuous signal Parameter of AE signal Acoustic Emission System Piping system Hydraulic Bench Volume water indicator AED2000V Integral preamp AE sensor Grease Computer built-in with ADC card and Physical Acoustic AE win software Acoustic Emission Detector Software Rough pipe Point location of sensor Controlled the valve of 90 opened position 37

13 xiii 3.13 Controlled the valve of 360 opened position RMS value for smooth pipe at each valve opening RMS value for rough pipe at each valve opening The fluid flow through smooth pipe with high flow rate and low flow rate 4.4 The fluid flow through rough pipe with high flow rate and low flow rate The high flow rate fluid flow in smooth pipe and rough pipe The low flow rate fluid flow in smooth pipe and rough pipe Bangi number plot for RMS Point location of point 1 and point Bangi number (AB) from point 3 to point Inner surface of smooth pipe 54

14 xiv LIST OF SYMBOLS µ Viscosity Č Roughness D d Diameter Inner diameter e f g L Q V ρ A Inner roughness Friction fator Gravity acceleration Length Volume flow rate Velocity Density Cross Sectional Area mm Millimetre h f frictional resistance s Second

15 xv t Thickness kurt( X ) R e Kurtosis Reynolds number

16 xvi LIST OF ABBREVIATIONS AB AE ADC AED AET FE FEA NASA NDT PC REACT RMS SCC X-ray Bangi number Acoustic Emission Analogue to Digital Converter Acoustic Emission Detector Acoustic Emission Testing Finite Element Finite Element Analysis National Aeronautic and Space Administration Non-destructive Test Personal Computer Research Engineering Applications Certificate Training Root Mean Square Stress Corrosion Cracking Radiographic

17 CHAPTER 1 INTRODUCTION 1.1 INTRODUCTION Pipes are use widely in our domestic and industries (G.Budenkov et al, 2006). Every pipe manufacturer supplies characteristic curves for their equipments illustration pipe performance under given condition. Pipe is the most important part in human life because it gives the basic of human need, such as for drink, bath, cooking and others. Piping system most important as the medium of delivering fluid such as water, gas, petroleum and other from tank to another tank. A few years ago, there also have many researches about to improve the monitoring system of piping in condition of piping line. There are a lot of methods that have involved in this research of monitoring pipe such as simulation, radiographic (Xray), ultrasonic test and Eddy current test (S. A.Stefani et all, 1996). But, normally of the company will mark on the non-destructive test (NDT) method because it have many advantages of saving time, more easy to inspected on many area and it s low cost methods (G.Martin and J.Dimopoulos, 2006). For this study, the acoustic emission (AE) technique was used to monitor the internal of pipe surface. This is almost in group of NDT and this method still newbie in contacts of piping system. This technique almost refers to transient elastic waves produce by a sudden redistribution of stress in materials ( M.Surgeon, 2004).

18 2 When subjected to external stimulus such as change in pressure, load, temperature, it will localized sources trigger and release of energy. The energy will be release in form of stress waves and it will propagate to the surface and recorded by the sensors. AE is commonly detects the sources from natural event like earthquakes and rock burst. In composites, AE can detect matrix cracking, fiber breakage and debonding. It also can detect any changes in polymers, wood and concrete (M.Surgeon, 2004). This method also gives low cost, high sensitivity and can be done by online. This method can proceed without interrupt the operation and breaking any part of components (G.Martin and J.Dimopoulos, 2006). This technique will use a sensor which is located at the components and will sense the elastic waves known as AE signal that can indicate the condition of component and parts that before it become catastrophic. The most commercial NDT method for this piping system is ultrasonic testing method but AE technique will give us the solution of detection and monitoring in piping systems. 1.2 OBJECTIVES For this project, the main objectives are: i. To detect Acoustic Emission (AE) signal from internal surface pipe ii. To classify smooth or rough of internal surface pipe using Acoustic Emission (AE) technique. 1.3 SCOPE OF STUDY For this project, the acoustic emission method will be use to detect a signal from internal surface pipe. From this technique also want to study a method to classify smooth or roughness surface of internal pipe with Acoustic Emission (AE) which is root mean square (RMS). Data from this parameter will be analyzed to get the characteristics of acoustic.

19 3 1.4 IMPORTANT OF THE STUDY This study is important to give the necessary method in determining internal pipe roughness. It also can use in analysis of AE characteristics or parameters to be used in pipe roughness analysis. It is more benefits than using non destructive testing (NDT) because of the operational can running without interruption the operation.

20 CHAPTER 2 LITERATURE REVIEW 2.1 FLOW ANALYSIS IN A CIRCULAR PIPE Fluids flow in a pipe depends largely on the pipe diameter D and on the physical characteristics of the fluid, velocity V, density ρ, and dynamic viscosity µ. Inside pipe, monophasic fluid flow is either turbulent or laminar flow. In laminar flow, the fluid layers slide smoothly over each other. Momentum exchange is at molecular scale. Instabilities are damped by viscosity, producing viscous shear forces that resist the relative motion of adjacent fluid layers. The velocity profile of laminar flow increases uniformly in a parabolic fashion from the pipe wall inward across the pipe. In turbulent flow, the fluid exhibits erratic motion with a violent exchange of momentum and locally circulating currents-vortices-resulting in a flatter velocity profile across the pipe. The different of the flow can be described as shown as the figure 2.1,

21 5 Figure 2.1: Laminar and Turbulent flow Source: PipeFlow.co.uk There are few parameters that can affect a flow characteristic such as flow velocity, diameter pipe, kinematics viscosity of fluid and the roughness parameter, Č. Most of the commercial pipes are come with their own roughness value. There are some of material roughness values can be described as shown in table 2.1, Table 2.1: Internal roughness (e) of common pipe materials Type of pipe e(mm) e(inch) Cast iron (Asphalt dipped) Cast iron Concrete Copper PVC Steel Steel (Galvanized) Source: PipeFlow.co.uk

22 6 A fluid character is determined by the dimensionless Reynolds number, the ratio of the fluid s inertial forces momentum to its static frictional forces viscosity. This dimensionless number can be determined using the equation 2.1, ρvd R e = µ (2.1) Where, ρ is fluid density, V is flow velocity, D is diameter pipe and µ is dynamic viscosity of fluid. If Re less than about 2000, the fluid flow will be laminar, and if Re is greater than 4000, the flow will be fully turbulent, with a transition region between. In the transition region, the flow profile depends on whether the fluid is free of disturbances, especially in the fluid inlet area. The flow of velocity can be determined using the equation 2.2, V= Α Q (2.2) Where, Q is volume flow rate and A is pipe cross section area. The friction factor, f for laminar flow can be calculated from the equation 2.3, f = 64 R e (2.3) Eddy currents concept that is induced inside the pipe body by a test coil. An alternating electrical is passed through the test coil to produce a magnetic field and currently are present within the flow and the ratio of the internal roughness of the pipe to the internal diameter of the pipe needs to be considered to be able to determine the friction factor (Ray T. Ko and Norman D. Schehl, 2008). In large diameter pipes the overall effect of the eddy currents is less significant. In small diameter pipes the internal roughness can have a major influence on the friction factor. The relative roughness of

23 7 the pipe and the Reynolds number can be used to plot the friction factor on a friction factor chart. The friction factor can be used with the Darcy-Weisbach formula to calculate the frictional resistance in the pipe using the equation 2.4, h f = f L D 2 v 2g (2.4) where h f is head loss (m), f is friction factor, L is length of pipe work (m),d is inner diameter of pipe work (m), v is velocity of fluid (m/s), g is acceleration due to gravity (m/s²) Between the Laminar and Turbulent flow conditions (Re 2300 to Re 4000) the flow condition is known as critical. The flow is neither wholly laminar nor wholly turbulent. It may be considered as a combination of the two flow conditions (Baranov.V et al, 2007). The friction factor for turbulent flow can be calculated from the Colebrook- White equation: 1 = log f 10 e D R f e for Re>4000 (2.5) Where f is friction factor, e is internal roughness of the pipe; D is inner diameter of pipe work. For this early hypothesis, have state that when reading of turbulent more higher, the intensity of Acoustic Emission (AE) signal parameter increases.

24 8 2.2 ACOUSTIC EMISSION (AE) METHOD A Brief History of Acoustic Emission (AE) The number of applications to which the Acoustic Emission (AE) technique has been successfully applied is vast. Acoustic include detecting and locating errors in pressure vessels, damage assessment in fiber-reinforced polymer-matrix composites, monitoring welding applications and corrosion processes, various process monitoring applications, global or local long-term monitoring of civil-engineering structures bridges, pipelines, offshore platforms and fault detection in rotating elements and reciprocating machines (J. Makar and N.Chagnon, 1999). The scientific application of AE first emerged in the 1950's, but the decline of heavy industry, nuclear power and defense spending in the 1980s, together with some poor publicity, resulted in a quiet period for AE research. Nevertheless the technique has developed significantly and emerged as a very powerful method for numerous measurement problems, far beyond conventional non-destructive testing (M. Wevers, 1997). There is a transition to waveform-based analysis, which has opened up a new approach to AE analysis. Due to advances in high-speed digital waveform based AE instrumentation there is large numbers of success, improvements in high fidelity, high sensitivity broadband sensors and advanced PC-based signal analysis. The researchers an enhanced understanding of AE signal propagation, enabling a departure from traditional reliance on statistical analysis had given, significantly improving the monitoring capabilities of AE. New developments have raised new problems, not least of which is sensor technology. Sensors with broader frequency characteristics were replaced resonant transducers are useful in many applications. Issues of flat response, sensitivity and calibration need to be addressed. Modern data transfer methods such as network