International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 19

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1 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 19 Flow Velocity and Crack Angle Effect on Vibration and Flow Characterization for Pipe Induce Vibration Muhannad Al-Waily, Maher A.R. Sadiq Al-Baghdadi, Rasha Hayder Al-Khayat Abstract The flow through the pipe is effect on the vibration of the pipe and it is effect on the pipe frequency. The pipe frequency is therefore dependent on the velocity and properties of the liquid flow through the pipe. Then, the studying of flow induced vibration is very necessary of pipe structure application. In addition to, the crack found at the pipe influenced on the flow distribution and pipe frequency, therefore, the crack direction is very impartment factor its effect on the pipe frequency. Then, in this study investigate the effect of velocity flow and crack parameters as length and orientation, for crack in longitudinal direction, on the pipe frequency and effect of crack on the flow distribution, where it is supported as simply supported pipe condition. Where, results of vibration pipe behavior evaluate by using experimental and numerical technique by using finite element method (using CFD technique), and then, comparison the results with its. Also, the comparison of data shows that the maximum error between experimental and finite element method is not exact (10.5%). Finally, the results shown the pipe frequency is affect with various crack pipe length and orientation and the minimum effect of crack at longitudinal crack orientation. Also, the study included shown the effect of crack on the deformation and mode shape of pipe with different crack length and orientation. In addition to, the investigation shows the increase for flow velocity of flow cause decreasing the frequency of flow. Index Term-- Flow Induces Vibration, Crack Pipe, Longitudinal Crack, CFD Crack Pipe Vibration, Finite Element Vibration Pipe, Oblique Crack Effect, Velocity Effect on Pipe Vibration. I. INTRODUCTION Vibrations of pipes conveying fluid is an important problem present in chemical plants, hydraulic power systems and petroleum industry. A flowing with speed higher than critical may cause the loss of stability of pipe by divergence. In other words, the vibration with time is decreases at each applied disturbance of pipe. Also, shows that the vibration of system is increase with time by any value of a small disturbance, for fluid flow velocity higher than a certain value, [1]. Many researchers presented the studies about the flow induce vibration of pipe with different parameters effect, therefore in following can be shown same of these studies and then shown the different between publication researches and present work, Muhannad Al-Waily Department of Mechanical Engineering, Faculty of Engineering, Al-Kufa University, Iraq, muhanedl.alwaeli@uokufa.edu.iq Maher A.R. Sadiq Al-Baghdadi Department of Mechanical Engineering, Faculty of Engineering, Al-Kufa University, Iraq, mahirar.albaghdadi@uokufa.edu.iq Rasha Hayder Al-Khayat Department of Mechanical Engineering, Faculty of Engineering, Al-Kufa University, Iraq, rashah.alkhayat@uokufa.edu.iq At 2002 Ayman Al-Maaitah et. al. [2], presented the mathematical model of equation of motion for Y-shaped tube with clamed end conditions. The mathematical model is resolved by using Galerkin approach, and the, evaluated of the Eigen values and Eigen function, in addition to, calculated the modes of pipe with different geometrical and parameters flow. Also, 2002 Dezhong Li et al. [3], was presented mathematical model of unsteady, viscous, and incompressible flow vibration, by using basic theory. Where, the study included evaluated the pressure and velocity distributions with various conditions. In addition to, it s studied the vibration behavior of pipe with different pipe structure and fluid properties. Also at 2014 K. KarthIk Selvakumar & L. A. Kumarasw Amidhas [4],This paper studied the fluid flow characteristics and the possibilities of suppressing the flow induced vibration excitation in elastically mounted solid square structures of aluminum and brass., an experimental analysis was performed at different conditions in an open type low turbulence wind tunnel. The results observed from the experimental study is compared and analyzed. Then, at 2015 S.M Shankaraachhar et.al. [5], Presented the development of mathematical model to study the vibrations and stability of fluid conveying pipe. The vibration structure of pipe was modeled by using IDEAS software as per specifications and the effect of turbulence of fluid flow in the piping element was analyzed by using Abaqus Software Finally, at 2016 Amol E Suradkar et. al. [6] This paper deals with the numerical analysis of flow induced vibration in pipes considered the effects of vibrations due to flow in a pipeline. Finite element model for a pipe was studied and developed it for analysis of vibration pipe carrying fluid. Also, is implemented the above developed model to simply supported pipe configuration which carries fluid. Also, at 2016 Muhsin J. Jweeg and Thaier J.Ntayeesh [7], presented analytical investigation of critical buckling velocity of pipe with different boundary conditions, as pinned-pinned fixed-pinned, and fixed-fixed supported pipe. The analytical solution included derive the general equation of motion of pipe with flow induce vibration to getting the semi-analytical solution of buckling pipe. Also, investigation the buckling velocity by using experimental technique, and then, comparison the results are getting together. In this research, is investigation the crack angle influence on the vibration characterization and influence of crack on flow distribution, by experimental and numerical solution. The effect of crack was studded included investigation the length, location and crack orientation on vibration and flow distribution characterization. Also, the results are comparison with them and shown the presented error for the two ways.

2 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 20 II. EXPERIMENTAL INVESTIGATION The experimental part included investigation the influence for crack length and angle on the frequency of simply supported pipe. Also, a crack parameters are studied in this work can be listing as, 1. Crack length, where the crack length variable as, 0.005L, L, 0.02L, and 0.03L. 2. Crack angle, where the crack angle variable as, 0 o, 20 o, 45 o, 75 o, and 90 o. And the floe velocity of fluid is variable as, 0.5 m/s, 1 m/s and 1.5 m/s. Where, these velocities are given laminar flow through the pipe. And the pipe studied has the parameters as shown in Table I. And the dimensions and shape of crack length and angle are shos in Fig. 1. Where, Fig. 1, shown the modelling of pipe testing in experimental part, thus, from figure can be see the crack position used at the middle position of pipe and the 0 o crack angle is parallel with the x-axis of pipe and increasing to 90 o to become perpendicular on x-axis for pipe. Also, the depth of crack is dependent on the length of crack at 90 o, so, when the crack angle is 90 o must be the crack depth increasing to agreement it length. Therefore, the experimental stepping including, first fixed the pipe as simply supported pipe, and then fixed the vibration test machine at the pipe and then flow the water through the pipe, and measuring the flow velocity of water by ultrasonic flowmeter, and finally measuring the pipe frequency by output signal of digital oscilloscope, as shown in Fig. 2. Where, it figure shown the rig component of vibration pipe with effect of crack, and the component of vibration rig can be listing as, supported of pipe, pipe testing, water tank source, amplifier, digital oscilloscope to get out signal, and accelerometer, to measure the vibration response of pipe. Table I Material properties and dimensions of the pipe Mechanical Test value Pipe density 800 Kg/ m 3 Ultimate strength 40 N/mm 3 Ultimate elongation 800% Pipe modulus of elasticity 800 N/mm 2 Pipe length (m) 1 m Outer and inner diameters (m) 0.03 and 0.2 m Fluid flow Water Crack length Water source Fig.1. Modelling of pipe. Crack Pipe Supported Amplifier Oscilloscope Accelerometer Fig. 2. Vibration pipe rig. Output signal Time-domain a. Accelerometer output signal. First Peak Natural Frequency Frequency-domain After evaluating the output signal of vibration response by vibration rig machine, analysis the output signal by using Sig- View program with transformation the signal evaluated by (Accelerometer- Amplifier- Oscilloscope) from time-output function to frequency out-put function with using fast Fourier transformation technique (FFT), with Sig-View program. Finally, will evaluating the pipe frequency with different crack parameters effects, from maximum peak of FFT chart, [8, 9, 10], as shown in Fig, 3. Then, the results getting by experimental technique are comparison with results are evaluating by using numerical technique by using CFD technique. b. FFT signal, evaluated of Pipe Natural frequency. Fig. 3. Analysis of accelerometer output signal. III. NUMERICAL TECHNIQUE The numerical technique is presented two investigations, the first is evaluating the effect of crack on the flow distribution through the pipe, and second is evaluating the influence for crack parameters on vibration characterization (frequency and mode shape) of pipe with flow induce vibration. The computational domain in this study is considered to one pipe with 1 m length, 0.02 m, and 0.03 cm inner and outer diameters respectively, Fig. 4. The properties of pipe material used in this study are shown in Table I. The governing

3 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 21 equations were discretized and solved using Finite Element Method (FEM) in a commercial package COMSOL v5.2. Stringent numerical tests were performed to ensure that the solutions were independent of the grid size. A computational quadratic mesh consisting of a total of 7902 for domain elements, 4902 for boundary elements, also 984-edge for elements was found to provide sufficient spatial resolution Fig. 5. The coupled set of equations was solved iteratively, and the solution was considered to be convergent when the relative error was less than in each field between two consecutive iterations. Where, the numerical work included calculated the pipe frequency with angle crack influence on pipe with various flow velocities. Where, the velocity variable in this study are, 0.5, 1 and 1.5 m/sec. also, the velocity application it s given laminar flow of fluid through the pipe. In addition, the investigation included evaluated the influence of various crack angles on frequency pipe, where, the crack angles are variable from 0 o to 90 o. Fig. 4. Three-dimensional computational domain. a. Mash of pipe. without crack crack angle = 0 o crack angle = 20 o crack angle = 45 o crack angle = 75 o crack angle = 90 o b. Mach of pipe with different crack angle. Fig. 5. Computational mesh of the computational domain (quadratic). After this, comparison the results evaluated by numerical technique with results were evaluated by experimental technique to shows the agreement of technique used. Therefore, the comparison of results is given a good agreement between experimental and numerical technique with different flow velocity and crack angle effect. Therefore, can be using the numerical or experimental work to shown the dynamic characterization of pipe with various parameters effect of fluid flow or pipe defect. IV. RESULTS AND DISCUSSION The results of flow induced vibration of pipe, with properties of pipe and liquid flow through it are shown in table I, for pipe with middle crack location effect (for different crack orientation and length), included four parts, as, 1. Evaluated the flow distribution through the pipe with and without crack effect, can be calculating with using numerical technique by CFD technique. 2. Evaluated the crack orientation influence on the simply supported pipe frequency, can be calculated by using experimental and numerical techniques, and then, comparison the results. 3. Evaluated the effect of fluid flow velocity, using flow velocity (0.5, 1, and 1.5 m/s), on the pipe frequency with various crack influence, can be evaluated with numerical and experimental technique, and then, comparison the results together. 4. Evaluated the angle of crack influence on the mode shape behavior of pipe, can be calculated by using numerical technique with CFD technique. Therefore, the results shown in Fig. 6, illustrates the flow distribution through the pipe with and without crack, where, Fig. 6.a. illustrates the flow distribution without crack in pipe and Fig. 6.b. illustrates the flow distribution with crack effect. Then, form the figure seen that the flow distribution is making dis-continuous through pipe with crack, since the crack make sock point of flow due to irregular pressure through the pipe. So, will be turbulent the pressure through the pipe, which leads to increasing the vibration of the pipe. Also, due to decreasing the stiffness of pipe due to making the crack, then, the pipe frequency will be decreasing of pipe with crack effect for various fluid flow velocities, as shown in Figs. 7 to 13. Where, the pipe frequency with-out crack effect about ( Hz), and then, decreasing to about (17 Hz) with high effect of crack, for flow velocity 0.5 m/s. thus, the pipe frequency is decreasing with about (20%) with cark effect. Also, the pipe frequency with flow velocity about ( Hz), with-out crack, and the it s decrease to about (18.1 Hz) with increasing the flow velocity to 1.5 m/s. Therefore, the pipe frequency is decrease with about (15%) by increasing the flow velocity to 1.5 m/s, with various crack parameters effect. Therefore, to shown the fluid flow velocity influence, crack angle and length, first comparison the results evaluated by experimental and numerical methods to shown the agreement between its methods, as shown in Figs. 7, 8, and 9. Where, the figures shown the good agreement between experimental and numerical technique for different crack orientation and length effect and flow velocity 0.5, 1, and 1.5 m/s, respectively, with

4 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 22 maximum error about (10.5%). Second, will evaluating the influence of fluid flow velocity on the pipe frequency of flow induce vibration pipe, as shown in Fig. 10. So, from the figure show that the increase of flow velocity causes to decreasing the pipe frequency, since the increase of flow velocity leads to decrease the stiffness system of fluid-pipe structure, which leads to decreasing the pipe frequency. Third, will evaluating the effect of length for crack and orientation on the pipe frequency with different fluid flow velocities, as shows in Figs. 11, 12 and 13. Where, the figures shown that the pipe frequency at crack angle (0 o ) more than the pipe frequency with crack angle (90 o ), therefore, the pipe frequency is decrease by increasing the angle for crack, since, the crack effect on the stiffness of the pipe is increasing with increase of crack orientation (the crack is more effect when taken vertical shape). Also, the figures, shown the pipe frequency is decrease by increasing the length of crack, for the same reason, decrease the stiffness with increasing length of crack. Finally, the investigation included evaluated the effect of crack length and orientation on the pipe mode shape of pipe, as shown in Figs. 14, 15, 16, 17. Where the Figures are shown that the response of pipe is increase by increasing the length of crack and the maximum crack influence become at crack angle is 90 o (vertical crack). Since, the crack effect is increase by increasing angle for crack, therefore, the pipe stiffness is decrease by increasing the angle of crack. Thus, the increasing of crack angle given reduces of pipe mechanical properties and strength of pipe, leads to increasing the response of pipe with different crack length and various flow velocity effects. a. b. a. without crack effect c. b. with crack effect Fig. 6. Flow distribution through the pipe with and without crack effect. d. Fig. 7. Comparison between numerical and experimental pipe frequency with different crack length and various crack angle, for flow velocity 0.5 m/s.

5 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 23 a. a. b. b. c. c. d. Fig. 8. Comparison between numerical and experimental pipe frequency with different crack length and various crack angle effect, for flow velocity 1 m/s. d. Fig. 9. Comparison between numerical and experimental pipe frequency with different crack length and various crack angle, for flow velocity 1.5 m/s.

6 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 24 a. Crack Length = 0.005L Fig. 11. Pipe frequency with various crack length and angle effect, for flow velocity 0.5 m/s. b. Crack Length = L Fig. 12. Pipe frequency with various crack length and angle effect, for flow velocity 1 m/s. c. Crack Length = 0.02L d. Crack Length = 0.03L Fig. 10. Pipe frequency with different flow velocity effect and various crack parametric influence, it s evaluated by numerical technique. Fig. 13. Pipe frequency with various crack length and angle effect, for flow velocity 1.5 m/s.

7 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 25 a. Without Crack a. Without Crack b. Crack Angle=0 o b. Crack Angle=0 o c. Crack Angle=20 o c. Crack Angle=20 o d. Crack Angle=45 o d. Crack Angle=45 o e. Crack Angle=75 o e. Crack Angle=75 o f. Crack Angle=90 o Fig. 14. Effect of crack orientations on the mode shape for pipe, first and second modes with crack length 0.03L, for flow velocity 0.5 m/s and mode-1. f. Crack Angle=90 o Fig. 15. Effect of crack orientations on the mode shape for pipe, first and second modes with crack length 0.03L, for flow velocity 0.5 m/s and mode-2.

8 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 26 a. Without Crack a. Without Crack b. Crack Angle=0 o b. Crack Angle=0 o c. Crack Angle=20 o c. Crack Angle=20 o d. Crack Angle=45 o d. Crack Angle=45 o e. Crack Angle=75 o e. Crack Angle=75 o f. Crack Angle=90 o Fig. 16. Effect of crack orientations on the mode shape for the pipe, third and fourth modes with crack length 0.03L, for flow velocity 0.5 m/s and mode-3. f. Crack Angle=90 o Fig. 16. Effect of crack orientations on the mode shape for the pipe, third and fourth modes with crack length 0.03L, for flow velocity 0.5 m/s and mode-4.

9 International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:17 No:05 27 V. CONCLUSION From the presented work, that included evaluated the effect of crack with different parameters (length and angle) on flow distribution of water through the pipe and pipe vibration characterization (natural frequency and vibration response with various mode shapes), can be concluded the flowing list pints, 1. The experimental work is good tool to evaluate the influence for length and angle of crack on the pipe frequency with flow induce vibration, comparison with numerical technique by using CFD. Also, the numerical work by using CFD technique is good to evaluate the length and angle crack effect on the pipe frequency and vibration response with various mode shapes of simply supported pipe with flow induce vibration. 2. The comparison between experimental work and numerical technique, to evaluate the pipe frequency with flow induce vibration and crack effect, give the good agreement of pipe frequency results with maximum error about (10.5%), for different crack length and angle effect. 3. The increase of fluid flow velocity is cause decrease the pipe frequency with various crack influence parameters, as depth, location, and crack angel. 4. The crack causes shock in the flow distribution through the pipe, therefore, the flow distribution through pipe with put crack is continuous flow, but, the flow becomes discontinuous flow distribution through pipe with different crack length and angle. 5. The crack length decreasing the stiffness and the strength of pipe, therefore, with increasing of crack length the pipe frequency is decreasing, and, the vibration responses are increasing for different mode shapes of vibration simply supported pipe. 6. The increase of crack angle, from cark parallel to axis of pipe 0o to crack perpendicular on pipe axis 90o, cusses increasing of crack effect on stiffness and strength of pipe (decreasing the stiffness and strength of pipe), therefore, by increasing crack orientation decreasing the pipe frequency, also, it s increasing the vibration response of pipe with different mode shapes. REFERENCES 1- Peter Dorfler, Mirjam Sick, Andre Coutu Flow-Induced Pulsation and Vibration in Hydroelectric Machinery, Engineer s Guidebook for Planning, Design and Troubleshooting Springer-Verlag London, Ayman Al-Maaitah, Kamal Kardsheh Flow-Induced Vibration of Y-Shaped Tube Conveying Fluid Electronic Journal (Technical Acoustics), Vol. 2, Dezhong Li, Ning Mei, Defu Liu, Jianhui Lu, Xiang Shi, Dewei Li, Changqing Chen Numerical Study of Flow-Induce Vibration in Pipeline on Offshore Platform The 12th International Offshore and polar Engineering Conference, May, Kitakyushu, Japan, K. Karthik Selvakumar, L. A. Kumaraswamidhas A Study on Flow Induce Vibration Excition in Solis Square Structures International journal of Mechanical and Production Engineering Research and Development, Vol. 4, No. 4, S. M. Shankarachar, M. Radhakrishina, P. Ramesh Babu An Experimental Study of Flow Induce Vibration of Elastically Restrained Pipe Conveying Fluid Proceedings of the 15th International Mechanical Engineering Congress and Exposition IMECE15, November 13-19, Houston, Texas, USA, Amol E. Suradkar, Shubham R. Suryawanshi numerical Analysis of Fluid Flow Induce Vibration of Pipes-A Review International Journal of modern Trends in Engineering and Research, Vol. 3, No. 4, Muhsin J. Jweeg, Thaier J. Ntayeesh Determination of Critical Buckling Velocities of Pipes Conveying Fluid Rested on Different Supports Conditions International Journal of Computer Applications, Vol. 134, No. 10, Abdulkareem Abdulrazzaq Alhumdany, Muhannad Al-Waily, Mohammed Hussein Kadhim Al-jabery Theoretical and Experimental Investigation of Using Date Palm Nuts Powder into Mechanical Properties and Fundamental Natural Frequencies of Hyper Composite Plate International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS, Vol.16, No. 1, Muhannad Al-Waily, Thaier J. Ntayeesh Influence of Multi Wall Carbon Nanotube(MWCNTs) Reinforcement on the Mechanical Properties and Vibration Behavior of Composite Plates 1st International Conference on Recent Trends of Engineering Sciences and Sustainability, May, Abdulkareem Abdulrazzaq Alhumdany, Muhannad Al-Waily, Mohammed Hussein Kadhim Experimental investigation for powder reinforcement effect on mechanical properties and natural frequency of isotropic hyper composite plate with various boundary conditions International Journal of Energy and Environment, Vol. 6, No. 5, pp , Asst. Prof. Dr. Muhannad Al-Waily, Lecturer in Kufa University-Faculty of Engineering-Mechanical Engineering Department. Ph.D. in Mechanical Engineering-Applied Mechanics. Has published many academic oriented papers and books. Specialization: Vibration Analysis, Stress Analysis under Static and Dynamic Loading, Composite Materials, Fatigue Analysis of Engineering Materials, Mechanical Properties of Engineering Materials, Control and Stability of Mechanical Application, Damage (Crack and Delamination Analysis), Buckling Analysis, plate and shell study, vibration of composite beam; plate and shell analysis, flow induce vibration analysis, heat induce vibration analysis and other mechanical researches. Associate Editors of the International Energy and Environment Foundation (IEEF)-Applied Mechanics Research Center. Editor-in-Chief of International Journal of Energy and Environment (IJEE)-Issue on Applied Mechanics Research. And IEEE membership. Website: Contact: muhanedl.alwaeli@uokufa.edu.iq, muhannad.alwaily@ieee.org Dr. Maher A.R. Sadiq Al-Baghdadi is a lecturer in the Kufa University, Faculty of Engineering. He has published many academic and industrial oriented papers and books. His research interests include fuel cell technology; computational fluid dynamics (CFD); renewable energy; alternative fuels; and energy and environmental impact. President of the International Energy and Environment Foundation (IEEF). Editor-in-Chief of International Journal of Energy and Environment (IJEE). Contact: mahirar.albaghdadi@uokufa.edu.iq Asst. lecturer Rasha Hayder Al-Khayat, lecturer in the Kufa University, Faculty of Engineering, mechanical engineering department, M.Sc. in Mechanical Engineering-Power Mechanics. Specialization: computational fluid dynamics (CFD), renewable energy, heat transfer, fluid mechanics researches, internal combustion engines and other mechanical researches. Contact: rashah.alkhayat@uokufa.edu.iq