DESIGN OF WATER SUPPLY PIPE NETWORKS

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1 DESIGN OF WATER SUPPLY PIPE NETWORKS

2 DESIGN OF WATER SUPPLY PIPE NETWORKS Prabhata K. Swamee Ashok K. Sharma

3 Copyright # 2008 by John Wiley & Sons, Inc. All rights reserved Published by John Wiley & Sons, Inc., Hoboken, New Jersey Published simultaneously in Canada No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise, except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) , fax (978) , or on the web at Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) , fax (201) , or online at Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services or for technical support, please contact our Customer Care Department within the United States at (800) , outside the United States at (317) or fax (317) Wiley also publishes it books in a variety of electronic formats. Some content that appears in print may not be available in electronic formats. For more information about Wiley products, visit our web site at Library of Congress Cataloging-in-publication Data: Swamee, Prabhata K. (Prabhata Kumar), Design of water supply pipe networks / Prabhata K. Swamee, Ashok K. Sharma. p. cm. Includes bibliographical references and index. ISBN (cloth) 1. Water-pipes. 2. Water Distribution. 3. Water-supply Management. I. Sharma, Ashok K. (Ashok Kumar), II. Title. TD491.S B dc22 Printed in the United States of America

4 CONTENTS PREFACE xi NOTATIONS xiii 1 Introduction Background System Configuration Flow Hydraulics and Network Analysis Cost Considerations Design Considerations Choice Between Pumping and Gravity Systems Network Synthesis Designing a Piecemeal Subsystem Designing the System as a Whole Dividing the Area into a Number of Optimal Zones for Design Reorganization or Restrengthening of Existing Water Supply Systems Transportation of Solids Through Pipelines Scope of the Book 8 References 9 2 Basic Principles of Pipe Flow Surface Resistance Form Resistance Pipe Bend Elbows Valves Transitions Pipe Junction Pipe Entrance Pipe Outlet Overall Form Loss Pipe Flow Under Siphon Action 23 v

5 vi CONTENTS 2.3. Pipe Flow Problems Nodal Head Problem Discharge Problem Diameter Problem Equivalent Pipe Pipes in Series Pipes in Parallel Resistance Equation for Slurry Flow Resistance Equation for Capsule Transport 37 Exercises 41 References 41 3 Pipe Network Analysis Water Demand Pattern Head Loss in a Pipe Link Head Loss in a Lumped Equivalent Head Loss in a Distributed Equivalent Analysis of Water Transmission Lines Analysis of Distribution Mains Pipe Network Geometry Analysis of Branched Networks Analysis of Looped Networks Hardy Cross Method Newton Raphson Method Linear Theory Method Multi-Input Source Water Network Analysis Pipe Link Data Input Point Data Loop Data Node Pipe Connectivity Analysis Flow Path Description 74 Exercises 76 References 77 4 Cost Considerations Cost Functions Source and Its Development Pipelines Service Reservoir Cost of Residential Connection 86

6 CONTENTS vii Cost of Energy Establishment Cost Life-Cycle Costing Unification of Costs Capitalization Method Annuity Method Net Present Value or Present Value Method Cost Function Parameters Relative Cost Factor Effect of Inflation 92 Exercises 95 References 95 5 General Principles of Network Synthesis Constraints Safety Constraints System Constraints Formulation of the Problem Rounding Off of Design Variables Essential Parameters for Network Sizing Water Demand Rate of Water Supply Peak Factor Minimum Pressure Requirements Minimum Size of Distribution Main Maximum Size of Water Distribution Reliability Considerations Design Period of Water Supply Systems Water Supply Zones Pipe Material and Class Selection 109 Exercises 109 References Water Transmission Lines Gravity Mains Pumping Mains Iterative Design Procedure Explicit Design Procedure Pumping in Stages Long Pipeline on a Flat Topography Pipeline on a Topography with Large Elevation Difference 122

7 viii CONTENTS 6.4. Effect of Population Increase Choice Between Gravity and Pumping Systems Gravity Main Adoption Criterion 128 Exercises 130 References Water Distribution Mains Gravity-Sustained Distribution Mains Pumped Distribution Mains Exercises 139 References Single-Input Source, Branched Systems Gravity-Sustained, Branched System Radial Systems Branch Systems Pumping, Branched Systems Radial Systems Branched, Pumping Systems Pipe Material and Class Selection Methodology 159 Exercises 160 References Single-Input Source, Looped Systems Gravity-Sustained, Looped Systems Continuous Diameter Approach Discrete Diameter Approach Pumping System Continuous Diameter Approach Discrete Diameter Approach 177 Exercises 179 Reference Multi-Input Source, Branched Systems Gravity-Sustained, Branched Systems Continuous Diameter Approach Discrete Diameter Approach Pumping System Continuous Diameter Approach Discrete Diameter Approach 193

8 CONTENTS ix Exercises 195 References Multi-Input Source, Looped Systems Gravity-Sustained, Looped Systems Continuous Diameter Approach Discrete Diameter Approach Pumping System Continuous Diameter Approach Discrete Diameter Approach 206 Exercises 211 Reference Decomposition of a Large Water System and Optimal Zone Size Decomposition of a Large, Multi-Input, Looped Network Network Description Preliminary Network Analysis Flow Path of Pipes and Source Selection Pipe Route Generation Connecting Input Point Sources Weak Link Determination for a Route Clipping Synthesis of Network Optimal Water Supply Zone Size Circular Zone Strip Zone 235 Exercises 241 References Reorganization of Water Distribution Systems Parallel Networks Parallel Gravity Mains Parallel Pumping Mains Parallel Pumping Distribution Mains Parallel Pumping Radial System Strengthening of Distribution System Strengthening Discharge Strengthening of a Pumping Main Strengthening of a Distribution Main Strengthening of Water Distribution Network 254 Exercises 258 Reference 258

9 x CONTENTS 14 Transportation of Solids Through Pipelines Slurry-Transporting Pipelines Gravity-Sustained, Slurry-Transporting Mains Pumping-Sustained, Slurry-Transporting Mains Capsule-Transporting Pipelines Gravity-Sustained, Capsule-Transporting Mains Pumping-Sustained, Capsule-Transporting Mains 268 Exercises 273 References 273 Appendix 1 Linear Programming 275 Problem Formulation 275 Simplex Algorithm 276 Appendix 2 Geometric Programming 281 Appendix 3 Water Distribution Network Analysis Program 287 Single-Input Water Distribution Network Analysis Program 287 Multi-Input Water Distribution Network Analysis Program 322 INDEX 347

10 PREFACE A large amount of money is invested around the world to provide or upgrade piped water supply facilities. Even then, a vast population of the world is without safe piped water facilities. Nearly 80% to 85% of the cost of a total water supply system is contributed toward water transmission and the water distribution network. Water distribution system design has attracted many researchers due to the enormous cost. The aim of this book is to provide the reader with an understanding of the analysis and design aspects of water distribution system. The book covers the topics related to the analysis and design of water supply systems with application to sediment-transporting pipelines. It includes the pipe flow principles and their application in analysis of water supply systems. The general principles of water distribution system design have been covered to highlight the cost aspects and the parameters required for design of a water distribution system. The other topics covered in the book relate to optimal sizing of water-supply gravity and pumping systems, reorganization and decomposition of water supply systems, and transportation of solids as sediments through pipelines. Computer programs with development details and line by line explanations have been included to help readers to develop skills in writing programs for water distribution network analysis. The application of linear and geometric programming techniques in water distribution network optimization have also been described. Most of the designs are provided in a closed form that can be directly adopted by design engineers. A large part of the book covers numerical examples. In these examples, computations are laborious and time consuming. Experience has shown that the complete mastery of the project cannot be attained without familiarizing oneself thoroughly with numerical procedures. For this reason, it is better not to consider numerical examples as mere illustration but rather as an integral part of the general presentation. The book is structured in such a way to enable an engineer to design functionally efficient and least-cost systems. It is also intended to aid students, professional engineers, and researchers. Any suggestions for improvement of the book will be gratefully received. PRABHATA K. SWAMEE ASHOK K. SHARMA xi

11 NOTATIONS The following notations and symbols are used in this book. A A e A r a B C C 0 C A C c C D C e C m C ma C N C P C R C T C v c i D D e D min D n D o D s D d annual recurring cost, annuity annual cost of electricity annual installment capsule length factor width of a strip zone cost coefficient initial cost of components capitalized cost overall or total capitalized cost drag coefficient of particles capitalized cost of energy cost of pipe capitalized maintenance cost net cost cost of pump cost of service reservoir, replacement cost cost of pumps and pumping volumetric concentration of particles cost per meter of pipe i pipe link diameter equivalent pipe link diameter minimum pipe diameter new pipe link diameter existing pipe link diameter diameter of service connection pipe optimal pipe diameter confusor outlet diameter, spherical particle diameter, polynomial dual xiii

12 xiv NOTATIONS d E F F A F D F g F P F s F P F f f b f c f e f p g H h h a h b h c h f h j h L h m h mi h min h 0 h 0 h s I k I n I p I R I t I s i i L optimal polynomial dual establishment cost cost function annual averaging factor daily averaging factor cost of gravity main cost of pumping main cost of service connections optimal cost of pumping main optimal cost coefficient of surface resistance friction factor for intercapsule distance friction factor for capsule effective friction factor for capsule transportation friction factor for pipe annulus gravitational acceleration minimum prescribed terminal head pressure head allowable pressure head in pipes length parameter for pipe cost extra pumping head to account for establishment cost head loss due to surface resistance nodal head total head loss minor head losses due to form resistance minor head losses due to form resistance in pipe i minimum nodal pressure head in network pumping head; height of water column in reservoir optimal pumping head staging height of service reservoir pipe links in a loop input source supplying to a demand node pipe links meeting at a node compound interest, pipes in a route connecting two input sources flow path pipe input source number for a pipe pipe index total number of pipe links

13 NOTATIONS xv J 1, J 2 J s J t j j L k K 1, K 2 k f k fp k L k m k n k p k R k s k T kw k 0 L l M 1 M 2 MC m m P N R N n N p N t n n n L n s P P i P NC P NS P NA pipe link node input source node of a flow path for pipe i originating node of a flow path for pipe i node index total number of pipe nodes cost coefficient, loop pipe index, capsule diameter factor loops of pipe form-loss coefficient for pipe fittings form-loss coefficient for fittings in pth pipe total number of loops pipe cost coefficient modified pipe cost coefficient pump cost coefficient reservoir cost coefficient service pipe cost coefficient pump and pumping cost coefficient power in kilowatts capitalized cost coefficient pipe link length index first input point of route r second input point of route r cut-sets in a pipe network system pipe cost exponent pump cost exponent total pipes in route r number of input sources supplying to a demand node number of pipe links meeting at a node number of pipe links in flow path of pipe i input point index, number of pumping stages optimal number of pumping stages total number of input points number of connections per unit length of main power; population probability of failure of pipe i net present capital cost net present salvage cost net present annual operation and maintenance cost

14 xvi NOTATIONS P N P s p Q Q c Q e Q i Q s Q T Q Tn q q s R R s R R E r s s b s s T T u t c V V a V b V c V max V R V s w w x i1, x i2 z z o z L z n z x net present value probability of failure of the system number of pipe breaks/m/yr discharge critical discharge effective fluid discharge pipe link discharge sediment discharge, cargo transport rate total discharge at source (s) discharge at nth source nodal withdrawal service connection discharge Reynolds number Reynolds number for sediment particles, system reliability pipe bends radius cost of electricity per kilowatt hour rate of interest; discount rate ratio of mass densities of solid particles and fluid standby fraction ratio of mass densities of cargo and fluid fluid temperature, design period of water supply main life of component characteristic time velocity of flow average fluid velocity in annular space average fluid velocity between two solid transporting capsules average capsule velocity maximum flow velocity service reservoir volume volume of material contained in capsule sediment particles fall velocity, weights in geometric programming optimal weights in geometric programming sectional pipe link lengths nodal elevation nodal elevation at input point nodal elevation at supply point nodal elevation at nth node nodal elevation at point x

15 NOTATIONS xvii a valve closer angle, pipe bend angle, salvage factor of goods b annual maintenance factor; distance factor between two capsules b i expected number of failure per year for pipe i l Lagrange multiplier, ratio of friction factors between pipe annulus and capsule n kinematic viscosity of fluid 1 roughness height of pipe wall r mass density of water s peak water demand per unit area j length ratio h efficiency u capsule wall thickness factor u p peak discharge factor v rate of water supply DQ k discharge correction in loop k Superscript * optimal Subscripts e effective, spindle depth obstructing flow in pipe i pipe index i1 first section of pipe link i2 second section of pipe link L terminating point or starting point o entry point p pipe s starting node t track