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Ayed Lazhar Lamjed Hadj-Taïeb Ezzeddine Hadj-Taïeb 《Journal of Loss Prevention in the Process Industries》2013,26(6):1341-1351
This paper presents a technique for detecting and locating leaks in a single viscoelastic pipe, by means of transient analysis. The system studied is a reservoir-pipe-valve structure. The viscoelastic behavior of the pipe wall material is modeled by a generalized KelvinVoigt model. To determine the leak location, the mathematical formulation has been solved by the method of characteristics. The approach by the method of characteristics is often chosen because it is based on the concept of acoustic wave propagation which is the main mechanism of all transient events considered. The presence of the two leaks in a pipe partially reflects pressure waves initiated by the sudden closure of a downstream shut-off valve. These waves affect the shape and the amplitude of the time-history-pressure. The computed results describe the influence of the presence of two leaks on pressure time-history and the effect of leaks locations and sizes on the pressure signal behavior. The effect of the pipe wall viscoelasticity on the two leaks detection and sizing is also discussed. The leaks discharges are determined by resolving two independent equations derived from literatures and based on transient analysis. The friction and leaks depths effects on two leaks locations and sizing are involved. 相似文献
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Sami Elaoud Lamjed Hadj-Taïeb Ezzeddine Hadj-Taïeb 《Journal of Loss Prevention in the Process Industries》2010,23(5):637-645
This paper presents a technique for detection and location of leaks in a single pipe, by means of transient analysis, of hydrogen–natural gas mixtures flows. The method uses transient pressure waves initiated by the sudden closure of a downstream shut-off valve. The presence of a leak in a pipe partially reflects these pressure waves and allows for the location of the leak. Pressure waves are governed by two coupled non-linear, hyperbolic partial differential equations with pressure dependent coefficients. The fluid pressure and velocity are considered as two principal dependent variables. To determine the leak location, the mathematical formulation has been solved by the characteristics method of specified time intervals. The computed results describe the influence of the leak on pressure time-history and the effect of hydrogen mass fraction in the mixture on the leak discharge behaviour. It was found that transient pressure is much important in the case of hydrogen than that in the case of natural gas. 相似文献
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Allouche Mohamed Nasri Ahmed Harrath Abdel Halim Mansour Lamjed Beyrem Hamouda Boufahja Fehmi 《Environmental science and pollution research international》2021,28(6):6866-6876
Environmental Science and Pollution Research - Meiobenthic nematodes are well-known bioindicators in aquatic ecosystem health programs. However, the explored taxa are still limited and practically... 相似文献
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Allouche Mohamed Nasri Ahmed Harrath Abdel Halim Mansour Lamjed Alwasel Saleh Beyrem Hamouda Plăvan Gabriel Rohal-Lupher Melissa Boufahja Fehmi 《Environmental science and pollution research international》2021,28(23):29484-29497
Environmental Science and Pollution Research - Numerous studies have focused on the response of meiofauna after exposure to polycyclic aromatic hydrocarbons (PAHs), but none has been devoted to... 相似文献
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