Vol. 2 (2012) No. 3 ISSN: 2088-5334 Blockage Detection in Circular Pipe Using Vibration Analysis N. L. T. Lile 1 , M. H. M. Jaafar 2 , M. R. Roslan 1 , M. S. Muhamad Azmi 1 1 School of Mechatronic Engineering, Universiti Malaysia Perlis, Malaysia E-mail: liyanatajul@unimap.edu.my, morafiq09@gmail.com, safwanazmi@unimap.edu.my 2 School of Manufacturing Engineering, Universiti Malaysia Perlis, Malaysia E-mail: hasnulhadi@unimap.edu.my Abstract— Pipe is an important medium used in most industrial and home applications for transferring liquid or gas from one end to the other. The efficiency of liquid flow is crucial to ensure proper and efficient delivering of medium carried. Liquid flow may be abrupt or ceased if blockage forms inside the circular pipe. This paper investigates the effect of blockage in circular pipe using vibration measurement. The main focus of this paper is to study the correlation of blockage levels to vibration signal. When fluid flow through an obstacle, the streamlines get closer which will increase the flow velocity and decrease the pressure. The vibration parameters are measured using accelerometer and the relationship between blockage levels to vibration signal are observed. It is found that vibration in pipe increases as the flow area gets smaller. This work expresses the potential of vibration analysis in assessing blockage inside a circular pipe with direct water flow. Keywords— vibration; blockage; circular pipe; fluid flow. I. INTRODUCTION Pipe is one of the means used widely to transport or send liquid or gas from a place to another. Pipes can be found in houses, buildings, sewage and industries where the needs of sending fluid without any obstructions are crucial. Sometimes for example in a piping system the liquid is not flowing continuously or even stop flowing due to impurities clogging on the internal area of the pipe. This would cause inefficiency in terms of delivering time and also the volume rate being transferred. In areas involving food processing, offshore pipelines and drainage system, where pipelines are very much in used, disturbance in pipe flows will create difficulties. Liquid with impurities and external objects entering the pipe will cause gradual built-up on the pipe surface area. Corrosion and rusting in pipes could also contribute to the irregularities in pipes where metal loss tends to deposit on the inner pipe surface. Apart from rusting, blockage precipitates inside pipes through supercooled water. Dendritic ice tends to form in water pipes under this condition since the nucleation of ice occurs between -4 to -6°C [1]. In some applications, small built up is not considered as major setback, yet if this phenomenon is not taken into deliberation in early stage, the flow of fluid will curtail. In some cases clogging could cause the pipe to burst due to internal pressure change. A number of researches have been conducted to identify blockage or obstacle in pipe to ensure the quality of medium being transferred. Reference [2] utilizes the rapid spectrum method to determine blockage in duct via single measurement of transfer function. Another investigation performed in [3] evaluates the effects of blockages on the nuclear power plant pressure transmitter sensing lines. Noticing the consequences of clogging, this paper discusses the impact of blockage in circular pipe. There are many ways of detecting faults in pipes and one of them is by non-destructive testing (NDT). This work focuses on determining the relationship of blockage levels towards the vibration pattern signal where the signals are generated from vibrating body of pipe. The changes in the vibration parameters with the varying blockage size are observed. II. METHODOLOGY The specimen used in this work is circular carbon steel pipe. This steel pipe of length 1000 mm and diameter of 30 mm is shown in Fig. 1. At the centre of the pipe, a blockage block is attached to create flow-blocking situation (Fig. 2). There are a total of four different blockage thicknesses of 5 mm, 10 mm, 15 mm and 20 mm attached inside the pipe. A. Simulation Simulation using SolidWorks Flow Simulation was conducted to observe the flow pattern inside the pipe. Water flow rate was set to 20 LPM (liter per minute). Five different 54