Multi-Step Homogenization of Thermoelastic Multi-Scale Tubes with Wavy Layers

In this paper we present a multi-step homogenization scheme of a tube made of numerous wavy cylindrical layers exhibiting periodicity with respect to both the radial and the angular direction. The proposed homogenization is a combination of successive semi-analytical, cell-problem-based, homogenization steps and a possible, micromechanics-based, homogenization in the interior of every layer. Every step of cell-problem based homogenization gives analytical expressions for the homogenized stiffness, thermal expansion and thermal conductivity

Design of a Novel In-Pipe Reliable Leak Detector

Leakage is the major factor for unaccounted losses in every pipe network around the world (oil, gas, or water). In most cases, the deleterious effects associated with the occurrence of leaks may present serious economical and health problems. Therefore, leaks must be quickly detected, located, and repaired. Unfortunately, most state-of-the-art leak detection systems have limited applicability, are neither reliable nor robust, while others depend on the user experience. In this paper, we present a new in-pipe leak detection system. It performs autonomous leak detection in pipes and, thus, eliminates the need for the user experience. This paper focuses on the detection module and its main characteristics. Detection in based on the presence of a pressure gradient in the neighborhood of the leak. Moreover, the proposed detector can sense leaks at any angle around the circumference of the pipe with only two sensors. We validate the concepts by building a prototype and evaluate the system’s performance under real conditions in an experimental laboratory setup.Center for Clean Water and Clean Energy at MIT and KFUPM (Project R7-DMN-08)Alexander S. Onassis Public Benefit Foundatio

Multiscale homogenization of multilayered structures

In this paper, the analytical solution of the multiple - step homogenization problem for multi - rank composites with generalized periodicity made of elastic materials is presented. The proposed homogenization scheme is combined with computational homogenization for solving more complex microstructures. Two numerical examples arepresented, concerning a “chevron” composite and a wavy fiber reinforced composite.European Union (European Social Fund ESF) and Greek national funds through the Operational Program ”Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: Thales

Multiscale homogenization of multilayered structures

In this paper, the analytical solution of the multiple - step homogenization problem for multi - rank composites with generalized periodicity made of elastic materials is presented. The proposed homogenization scheme is combined with computational homogenization for solving more complex microstructures. Two numerical examples arepresented, concerning a “chevron” composite and a wavy fiber reinforced composite.European Union (European Social Fund ESF) and Greek national funds through the Operational Program ”Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) - Research Funding Program: Thales

Design and Evaluation of an In-Pipe Leak Detection Sensing Technique Based on Force Transduction

Leakage is the major factor for unaccounted fluid losses in almost every pipe network. In most cases the deleterious effects associated with the occurrence of leaks may present serious economical and health problems and therefore, leaks must be quickly detected, located and repaired. The problem of leakage becomes even more serious when it is concerned with the vital supply of fresh water to the community. Leaking water pipelines can develop large health threats to people mostly because of the infiltration of contaminants into the water network. Such possibilities of environmental health disasters have spurred research into the development of methods for pipeline leakage detection. Most state of the art leak detection techniques have limited applicability, while some of them are not reliable enough and sometimes depend on user experience. Our goal in this work is to design and develop a reliable leak detection sensing system. The proposed technology utilizes the highly localized pressure gradient in the vicinity of a small opening due to leakage in a pressurized pipeline. In this paper we study this local phenomenon in detail and try to understand it with the help of numerical simulations in leaking pipelines (CFD studies). Finally a new system for leak detection is presented. The proposed system is designed in order to reduce the number of sensing elements required for detection. The main concept and detailed design are laid out. A prototype is fabricated and presented as a proof of concept. The prototype is tested in a simple experimental setup with artificial leakages for experimental evaluation. The sensing technique discussed in this work can be deployed in water, oil and gas pipelines without significant changes in the design, since the concepts remain the same in all cases.King Fahd University of Petroleum and Minerals (Project Number R7-DMN-08

Analysis and Design of an In-Pipe System for Water Leak Detection

In most cases the deleterious effects associated with the occurrence of leaks may present serious problems and therefore, leaks must be quickly detected, located and repaired. The problem of leakage becomes even more serious when it is concerned with the vital supply of fresh water to the community. In addition to waste of resources, contaminants may infiltrate into the water supply. The possibility of environmental health disasters due to delay in detection of water pipeline leaks has spurred research into the development of methods for pipeline leak and contamination detection. Leaking in water networks has been a very significant problem worldwide, especially in developing countries, where water is sparse. Many different techniques have been developed to detect leaks, either from the inside or from the outside of the pipe; each one of them with their advantages, complexities but also limitations. To overcome those limitations we focus our work on the development of an in-pipe-floating sensor. The present paper discusses the design considerations of a novel autonomous system for in-pipe water leak detection. The system is carefully designed to be minimally invasive to the flow within the pipe and thus not to affect the delicate leak signal. One of its characteristics is the controllable motion inside the pipe. The system is capable of pinpointing leaks in pipes while operating in real network conditions, i.e. pressurized pipes and high water flow rates, which are major challenges.Center for Clean Water for Clean Energy at MIT & KFUP

Multi-Step Homogenization of Thermoelastic Multi-Scale Tubes with Wavy Layers

In this paper we present a multi-step homogenization scheme of a tube made of numerous wavy cylindrical layers exhibiting periodicity with respect to both the radial and the angular direction. The proposed homogenization is a combination of successive semi-analytical, cell-problem-based, homogenization steps and a possible, micromechanics-based, homogenization in the interior of every layer. Every step of cell-problem based homogenization gives analytical expressions for the homogenized stiffness, thermal expansion and thermal conductivity

Effective behavior of thermo-elastic tubes with wavy layers

In the present article, the homogenization of a composite star-shaped tube with numerous thin, periodic, elastic wavy layers, is presented. The composite exhibits a multiscale periodicity allowing for a multistep asymptotic homogenization scheme starting from the finest scale. The scheme gives the complete effective thermoelastic behavior of the composite. By a numerical example of a two-phase composite with sinusoidal wavy walls, whose effective behavior is an orthotropic material, the above method is illustrated

Quantifying Acoustic and Pressure Sensing for In-Pipe Leak Detection

Experiments were carried out to study the effectiveness of using inside-pipe measurements for leak detection in plastic pipes. Acoustic and pressure signals due to simulated leaks, opened to air, are measured and studied for designing a detection system to be deployed inside water networks of 100 mm (4 inch) pipe size. Results showed that leaks as small as 2 l/min can be detected using both hydrophone and dynamic pressure transducer under low pipe flow rates. The ratio between pipe flow rate and leak flow rate seems to be more important than the absolute value of leak flow. Increasing this ratio resulted in diminishing and low frequency leak signals. Sensor location and directionality, with respect to the leak, are important in acquiring clean signal.King Fahd University of Petroleum and Mineral