Estimation of Location and Discharge of Water Leak from Transient Pressure Waves in Pipelines

2018 ◽  
Vol 74 (4) ◽  
pp. I_613-I_618 ◽  
Author(s):  
Yohei ASADA ◽  
Masaomi KIMURA ◽  
Issaku AZECHI ◽  
Toshiaki IIDA ◽  
Naritaka KUBO
Keyword(s):  
Pressure Waves ◽  
Transient Pressure ◽  
Water Leak

Experimental investigation on multi-cycle two-phase spiral pulse detonation tube of two configurations

2018 ◽  
Vol 233 (11) ◽  
pp. 4166-4175
Author(s):  
Hua Qiu ◽  
Zheng Su ◽  
Cha Xiong
Keyword(s):  
Pressure Waves ◽  
Propagation Characteristics ◽  
Transient Pressure ◽  
Two Phase ◽  
Pulse Detonation ◽  
Compression Waves ◽  
Detonation Tube ◽  
Deflagration To Detonation Transition ◽  
Pulsed Detonation ◽  
Detonation Transition

The spiral tube structure is an effective method to shorten the axial length of the pulse detonation chamber. In this article, spiral pulsed detonation tube with two kinds of spiral configuration was experimentally investigated. Liquid gasoline and air were used as fuel and oxidant, respectively, and equivalence ratios were controlled to about 1.0. Based on the transient pressure along the tube, the propagation characteristics of the pressure waves in the multi-cycle spiral pulsed detonation tubes, such as pressure peaks, wave velocities and propagation process, were analyzed. Results showed that propagation of double compression waves was the common feature during the process of deflagration to detonation transition in the presented spiral tubes, and the onset of detonation was initiated by a local explosion in the second compression wave. The deflagration to detonation transition characteristics with detonation initiation and combustion characteristics without initiation in the spiral sections were both related to the dimensionless distance. Propagation characteristics of the pressure waves were influenced by the use of different spiral configuration. And some interesting phenomena were also found.

A Calculation Model for Leak Detection and Location of Single Pipeline With Two Leaks

2018 ◽  
Author(s):  
Xu Diao ◽  
Juncheng Jiang ◽  
Lei Ni ◽  
Yong Pan ◽  
Qiang Chen
Keyword(s):  
Linear Equations ◽  
Time Domain Analysis ◽  
Economic Loss ◽  
Calculation Model ◽  
Pressure Waves ◽  
Transient Pressure ◽  
Transient Event ◽  
Leak Location ◽  
Pipeline Valve ◽  
Transportation Modes

Pipeline, as one of the transportation modes, is playing an increasingly important role in national economy. But leakages in pipelines may cause severe problems, such as environmental damages and economic loss. Therefore, how to calculate the leak location and leak size has been investigated for last decades. This paper presents a calculation model based on time-domain analysis solution for detecting and locating two leaks in the pipeline. The model is based on a transient event that is generated by fast closure of the valve at the end of a reservoir-pipeline-valve (RPV) system. The presence of leak causes continuous drops in pressure waves and leak information can be revealed by analyzed the leak transient pressure waves. The time of reflection wave represents the leak location and the magnitude of the piezometric head represents the leak size. The governing equations for calculating the leak size are derived as a system of linear equations based on the Method of Characteristics (MOC). The first transient pressure wave was analyzed to obtain the calculation parameters. Then the applicability of this method is verified on simulated pressure data. The results indicate that this model can perfectly solve two leaks problem in a single pipeline.

A one-dimensional model for the propagation of transient pressure waves through the lung

2002 ◽  
Vol 35 (8) ◽  
pp. 1081-1089 ◽  
Author(s):  
Quentin Grimal ◽  
Alexandre Watzky ◽  
Salah Naili
Keyword(s):  
Pressure Waves ◽  
Dimensional Model ◽  
Transient Pressure ◽  
One Dimensional

scholarly journals Pressure Wave Transmission in a Fluid Contained in a Plastically Deforming Pipe

1974 ◽  
Vol 96 (4) ◽  
pp. 258-262 ◽  
Author(s):  
G. L. Fox ◽  
D. D. Stepnewski
Keyword(s):  
Plastic Deformation ◽  
Pressure Wave ◽  
Pipe Wall ◽  
Experimental Tests ◽  
Elastic Wave Velocity ◽  
Wave Transmission ◽  
Pressure Waves ◽  
Transient Pressure ◽  
Cooling Systems ◽  
Wall Deformation

The transmission of high pressure pulses through piping loops such as reactor cooling systems is usually studied with water hammer analysis techniques. Conventional wave analysis includes only elastic pipe wall deformation. However, plastic deformation of the pipe wall is effective in reducing the magnitude of transmitted pressure waves if the pressure is of sufficient magnitude to cause plastic yielding. This effect can be treated using a one-dimensional dynamic analysis by noting the similarity between the equations describing pressure wave induced plastic deformation in a solid bar and wave transmission causing plastic strain in a fluid filled pipe. The results of the analysis show that at fluid pressures less than the pipe yield pressure, waves are transmitted at elastic wave velocity; however, at pressures which exceed the pipe yield point, wave velocities are substantially reduced and the waves are dispersed. These results demonstrate that plastic deformation from transient pressure loading is limited to a relatively short length of piping near the source of the pressure pulse. The significance of this behavior with respect to reactor cooling systems is that pressures above those causing yield are not transmitted to primary loop components such as pumps and heat exchangers. The theoretical results are compared with experimental tests and show reasonable agreement.

Radial Pressure Wave Behavior in Transient Laminar Pipe Flows Under Different Flow Perturbations

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Tong-Chuan Che ◽  
Huan-Feng Duan ◽  
Pedro J. Lee ◽  
Silvia Meniconi ◽  
Bin Pan ◽  
...  
Keyword(s):  
Radial Pressure ◽  
Research Area ◽  
Laminar Flows ◽  
Generation Mechanism ◽  
Detection Methods ◽  
Pressure Waves ◽  
Pressure Gradients ◽  
Transient Pressure ◽  
Pipe Flows ◽  
2D Model

The study of transient pressure waves in both low- and high-frequency domains has become a new research area to provide potentially high-resolution pipe fault detection methods. In previous research works, radial pressure waves were evidently observed after stopping the laminar pipe flows by valve closures, but the generation mechanism and components of these radial pressure waves are unclear. This paper intends to clarify this phenomenon. To this end, this study first addresses the inefficiencies of the current numerical scheme for the full two-dimensional (full-2D) water hammer model. The modified efficient full-2D model is then implemented into a practical reservoir-pipeline-valve (RPV) system, which is validated by the well-established analytical solutions. The generation mechanism and components of the radial pressure waves, caused by different flow perturbations from valve operations, in transient laminar flows are investigated systematically using this efficient full-2D model. The results indicate that nonuniform changes in the initial velocity profile form pressure gradients along the pipe radius. The existence of these radial pressure gradients is the driving force of the formation of radial flux and radial pressure waves. In addition, high radial modes can be excited, and the frequency of flow perturbations by valve oscillation can redistribute the energy entrapped in each high radial mode.

Transient Impact of Valve Closure Times: Disagreements Between Design and Application

2017 ◽  
Author(s):  
Ilker T. Telci ◽  
Shesh R. Koirala
Keyword(s):  
Transient Analysis ◽  
Lag Time ◽  
Field Conditions ◽  
Dynamic Loads ◽  
Design Stage ◽  
Pressure Waves ◽  
Valve Closure ◽  
Pipe Network ◽  
Transient Pressure ◽  
Transient Event

Many pressurized liquid systems require emergency shut down procedures in order to prevent damage to the piping and components, environmental contamination and fire hazard. The emergency shutdowns (ESDs) are facilitated by fast closing on-off valves installed at various locations along the piping system. When these valves close they create transient pressure waves traveling through the pipe network. These waves can be reflected at the dead-ends or closed valves. At locations where the pressure decreases below the vapor pressure, liquid column separation followed by a rejoining can cause creation of new transient pressure waves. As these waves travel, they may meet and superpose. These complex surge pressure wave behaviors require modeling of the pipe network and simulation of the transient event as the first step of a transient analysis. The second step of the transient analysis is to pin point the problems such as excessive surge pressures and dynamic loads that may occur in the system. The third step is to provide recommendations to prevent undesired transient consequences. One of the most important components of these recommendations include valve closure times during ESDs. Recent field measurements on the valve closure rates showed that the valve closure times recommended by the transient analysis were not accurately implemented. One reason for this disagreement between the designed closure rates and the applied closure rates is that the actuators of the valves introduce a time lag between the shutdown signal and start of valve closure. Another reason comes from the decision taken by the operator adjusting the actuator timing. Some operators may adjust the actuators such that the valves close within the prescribed time including the lag time which may result in very fast valve closures depending on the lag of the actuators. Other operators may choose to close the valves within the prescribed time including the lag time or even slower than the recommended rates. This may impair the orchestrate of the valve closure events designed in the transient analysis resulting in excessive surge pressures or dynamic loads. This study investigates (i) the discrepancies between the recommendations from transient study made early in the design stage and (ii) the transient impact due to the deviation and/or misinterpretation of those recommendations. Specifically, in this study, these problems are demonstrated in a case study from LNG - Ship loading systems. The results indicated that transient analysis is the essential tool in finding critical components of the system in the field conditions providing a variety of solutions such as valve closure rate adjustments, flow rate reduction at the beginning of ESDs via pump trips and pipe size increase at dead legs. This study showed that the pressure piping systems can deviate from initial design under dynamic field conditions and frequent inspections of the ESD valves are crucial for safe operations of these systems.

On the Transient of Pressure Waves in Ducts for Systems Operating in Industrial Automation

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Arcangelo Messina ◽  
Giosué Rollo
Keyword(s):  
System Modeling ◽  
Practical Interest ◽  
Point Of View ◽  
Finite Volumes ◽  
Pressure Waves ◽  
Transient Pressure ◽  
Industrial Automation ◽  
Global Dynamic ◽  
Study Results ◽  
Experimental Validations

Within the frame of industrial automation, the mechanical power related to pneumatic actuator systems involves air flows along with mechanical component, such as valves, connecting tubes, cylinder chambers and possible linkages in order to finally actuate a specific objective. Gas dynamic of the air flowing into connecting ducts plays a fundamental role in the description of the global dynamic phenomena of these systems. Several studies deal with the dynamics of such pneumatic systems but through streamlined analysis where the influence of pressure-waves propagating in ducts is neglected or poorly described. The related models are even more complex when finite volumes are placed at the ends of connecting lines. In this paper, two different mathematical models describing transient pressure-waves propagating through lines closed by finite volumes are presented. The investigation regards pressure and velocity ranges normally operating in industrial pneumatic systems. Besides the value of new system modeling of different complexity, these models are compared from an analytical and numerical point of view; advantages, disadvantages, weakness, abilities, and inabilities are highlighted and, finally, the relevant analysis is corroborated through experimental validations of wave propagating pressure at fixed positions of ducts. This study results both in the presentation of models of practical interest, as well as in an attempt to provide an elucidation on the need to resort to an accurate model rather than a streamlined one with respect to the geometric and/or operative characteristics of industrial pneumatic systems.

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