A Framework for Alternative Formulations of the Pipe Network Equations

The aim of this paper is to revisit the formulations of the equations for flows and heads in water distribution systems and provide clarity for a logical presentation of a framework for the different formulations. Five formulations are described including 1) flow equations where the equations are formulated only in terms of the unknown flows in a network 2) head equations 3) loop flow equations 4) flow and head equations and 5) the Todini and Pilati flow and head formulation. Graph theory is used to show how many unknowns are required to be solved for in each of the five formulations. A Newton solution method is derived for the flow formulation and the Todini and Pilati formulation. © 2009 ASCE.Angus R. Simpson and Sylvan Elha

Optimal design of hydraulic capsule pipelines transporting spherical capsules

Scarcity of fossil fuels is affecting efficiency of established modes of cargo transport within transportation industry. Extensive research is being carried out on improving efficiency of existing modes of cargo transport, as well as to develop alternative means of transporting goods. One such alternative method can be through the use of energy contained within fluid flowing in pipelines in order to transfer goods from one place to another. The present study focuses on the use of advanced numerical modelling tools to simulate the flow within Hydraulic Capsule Pipelines (HCPs) transporting Spherical Capsules with an aim of developing design equations. Hydraulic Capsule Pipeline is the term which refers to the transport of goods in hollow containers, typically of spherical or cylindrical shapes, termed as capsules, being carried along the pipeline by water. HCPs are being used in mineral industries and have potential for use in Oil & Gas sector. A novel modelling technique has been employed to carry out the investigations under various geometric and flow conditions within HCPs. Both qualitative and quantitative flow analysis has been carried out on the flow of spherical shaped capsules in an HCP for both on-shore and off-shore applications. Furthermore, based on Least-Cost Principle, an optimisation methodology has been developed for the design of single stage HCPs. The input to the optimisation model is the solid throughput required from the system, and the outputs are the optimal diameter of the HCPs and the pumping requirements for the capsule transporting system

Protocolo para la rutina en la deformación de la seccion transversal por alta temperatura en tuberías de agua caliente - CPVC

Trabajo de InvestigaciónEste trabajo de investigación presenta los análisis realizados al banco hidráulico de agua caliente de la Universidad Católica de Colombia, con el objetivo de realizar un protocolo para la rutina de la tubería CPVc (Policloruro de Vinilo Clorado) y la parametrización de una serie de ecuaciones que expresen de manera general el comportamiento de dichas tuberías a lo largo de su vida útil; se obtienen una serie datos mediante prácticas de laboratorio tales como: caudal, presión, volumen, temperatura, pérdidas de carga, entre otras, que permiten establecer a través de la organización de tablas dinámicas las condiciones que interfieren cotidianamente en las tuberías para agua caliente en redes domiciliarias. El análisis de los datos obtenidos durante la investigación se compara con un escenario real en el ámbito de la construcción ya que, la información contenida en la investigación es una herramienta práctica para colegas, docentes y estudiantes1.INTRODUCCIÓN 2.PROBLEMA DE INVESTIGACIÓN 3.ANTECEDENTES Y LIMITACIONES 4.OBJETIVOS 5.JUSTIFICACIÓN 6.MARCO TEORICO 7.ESTADO DEL ARTE 8.METODOLOGÍA 9.RESULTADOS 10.CONCLUSIONES 11lRECOMENDACIONES 12.ANEXOS 13.BIBLIOGRAFÍAPregradoIngeniero Civi

Development of a Design Methodology for Hydraulic Pipelines Carrying Rectangular Capsules

The scarcity of fossil fuels is affecting the efficiency of established modes of cargo transport within the transportation industry. Efforts have been made to develop innovative modes of transport that can be adopted for economic and environmental friendly operating systems. Solid material, for instance, can be packed in rectangular containers (commonly known as capsules), which can then be transported in different concentrations very effectively using the fluid energy in pipelines. For economical and efficient design of such systems, both the local flow characteristics and the global performance parameters need to be carefully investigated. Published literature is severely limited in establishing the effects of local flow features on system characteristics of Hydraulic Capsule Pipelines (HCPs). The present study focuses on using a well validated Computational Fluid Dynamics (CFD) tool to numerically simulate the solid-liquid mixture flow in both on-shore and off-shore HCPs applications including bends. Discrete Phase Modelling (DPM) has been employed to calculate the velocity of the rectangular capsules. Numerical predictions have been used to develop novel semi-empirical prediction models for pressure drop in HCPs, which have then been embedded into a robust and user-friendly pipeline optimisation methodology based on Least-Cost Principle

Jacobian matrix for solving water distribution system equations with the Darcy-Weisbach head-loss model

Corrected by:Erratum: Jacobian Matrix for Solving Water Distribution System Equations with the Darcy-Weisbach Head-Loss Model, in Vol. 143, Issue 9, 08217002. There is a typographical error in Table 5. The formula for Case 3, the turbulent region (R≥4,000) in that table of the published paper.The widely used Todini and Pilati method for solving the equations that model water distribution systems was originally developed for pipes in which the head loss is modeled by the Hazen-Williams formula. The friction factors in this formula are independent of flow. Rossman's popular program EPANET implements elements of the Todini and Pilati algorithm, but when the Darcy-Weisbach head-loss formula is used, it does not take into account the dependence of the friction factors on the Reynolds number, and therefore flow, in computing the Jacobian. We present the correct Jacobian matrix formulas, which must be used in order to fully account for the friction factor's dependence on flow when the Todini and Pilati method is applied with the Darcy-Weisbach head-loss formula. With the correct Jacobian matrix the Todini and Pilati implementation of Newton's method has its normally quadratic convergence restored. The new formulas are demonstrated with an illustrative example. © 2011 American Society of Civil Engineers.Angus Simpson and Sylvan Elha

Medium Access Control for Opportunistic Concurrent Transmissions under Shadowing Channels

We study the problem of how to alleviate the exposed terminal effect in multi-hop wireless networks in the presence of log-normal shadowing channels. Assuming node location information, we propose an extension of the IEEE 802.11 MAC protocol that sched-ules concurrent transmissions in the presence of log-normal shadowing, thus mitigating the exposed terminal problem and improving network throughput and delay performance. We observe considerable improvements in throughput and delay achieved over the IEEE 802.11 MAC under various network topologies and channel conditions in ns-2 simulations, which justify the importance of considering channel randomness in MAC protocol design for multi-hop wireless networks

Study of microvascular blood flow modulated by electroosmosis

An analytical study of microvascular non-Newtonian blood flow is conducted incorporating the electro-osmosis phenomenon. Blood is considered as a Bingham rheological aqueous ionic solution. An externally applied static axial electrical field is imposed on the system. The Poisson-Boltzmann equation for electrical potential distribution is implemented to accommodate the electrical double layer (EDL) in the microvascular regime. With long wavelength, lubrication and Debye-Hückel approximations, the boundary value problem is rendered non-dimensional. Analytical solutions are derived for the axial velocity, volumetric flow rate, pressure gradient, volumetric flow rate, averaged volumetric flow rate along one time-period, pressure rise along one wavelength and stream function. A plug width is featured in the solutions. Via symbolic software (MathematicaTM), graphical plots are generated for the influence of Bingham plug flow width parameter, electrical Debye length (thickness) and Helmholtz-Smoluchowski velocity (maximum electro-osmotic velocity) on the key hydrodynamic variables. An increase in plug flow width is observed to accelerate the axial flow, enhance volumetric flow rate and has a varied influence on the pressure rise depending on whether the flow is in the free pumping or pumping region. Increasing electrical Debye length consistently enhances axial flow, volumetric flow rate and also pressure rise (at any value of volumetric flow rate)

PTV measurement of drag coefficient of fibrous particles with large aspect ratio

The aerodynamic behaviour of long aspect ratio nylon fibrous particles has been investigated experimentally while settling in air under super dilute conditions without any influence of secondary flows and at fibre Reynolds numbers of 0.5-2 based on fibre diameter. A method for laser-based measurement of the orientations and velocities of fibrous particles is also presented. The experimental apparatus employs a two-dimensional Particle Tracking Velocimetry (PTV) to calculate orientation and velocity based on the two end-points. The controlling length scale in the relationship between Reynolds number and drag coefficient was investigated and the equivalent diameter of settling fibre in air was reported. Finally the influence of volume fraction and fibre straightness were assessed. © 2012.Guo Q. Qi, Graham J. Nathan, Richard M. Kels