Introduction to Practical Fluid Flow

R. Peter King

• Publisher: Butterworth-Heinemann
• Year: 2002
• ISBN:
  9780080495842
• Topic: Naturwissenschaften
• Subtopic: Strömungsmechanik

Introduction to Practical Fluid Flow provides information on the the solution of practical fluid flow and fluid transportation problems through the application of fluid dynamics.

Emphasising the solution of practical operating and design problems, the text concentrates on computer-based methods throughout, in keeping with trends in engineering. With a focus on the flow of slurries and non-Newtonian fluids, it will be useful for and engineering students who have to deal with practical fluid flow problems.

Emphasises flow of slurries and Non-Newtonian fluids.Covers the application of fluid dynamics to the solution of practical fluid flow and fluid transportation problems.

1

Introduction

1.1 Fluid flow in process engineering

Process engineering deals with the processing of large quantities of material. In order to process materials, they must be transported to the processing plant, and they must be transported from one unit operation to another within the processing environment. Materials are usually transported in a fluid phase, because this is generally much easier and more cost-effective than transportation as a solid. Liquids can be easily moved through pipelines or open channels, and the energy that is required can be conveniently delivered to the fluid using a pump. Gases too can be transported economically by pipeline, but this book deals exclusively with the transportation of incompressible fluids. These include pure liquids, both Newtonian and non-Newtonian, and suspensions of solid particles in liquids that form slurries or pastes. Non-Newtonian fluids and suspensions are commonly encountered by chemical, metallurgical, mining, and civil engineers.

This book does not start from the usual definition of the fluid as a continuum from which the application of differential mass and momentum balances leads to the equation of continuity and the Navier–Stokes equations. The approach taken is macroscopic with an emphasis of solving problems of practical engineering significance. The accompanying computational toolbox provides the tools that are necessary to solve these problems with convenience, and the reader is expected to become familiar with the toolbox and its contents.

1.2 Dimensions, units, and physical quantities

A variety of physical quantities of both the fluids and the equipment will be used throughout this book. These quantities must be described quantitatively, for which sets of dimensions and units are required. For example, the density of a fluid is an important quantity that will influence the behavior of the fluid in most situations. The dimensions of density are mass per unit volume M/L³. To give the density a numerical value, a set of units must be selected for all the dimensions that are to be used. In this book all units will be specified in the SI (Système International) system. There is a good reason for this: the SI is the only practical set of units that is coherent. This means that no conversion factors are ever required when solving problems. This is in stark contrast to all other systems of units, including the metric system, which require difficult-to-remember conversion factors in almost every problem except perhaps only the most elementary and trivial. These older incoherent systems of units are now regarded as being obsolete for the purposes of scientific and technical calculations.

The SI is based on a set of fundamental dimensions and units as shown in Table 1.1. The precise size of each of the fundamental dimensions is defined by reference to a unique physical entity. Because the size of the fundamental dimensions that are used in the SI do not always conveniently match those of the physical quantities that are encountered in practical problems, a set of prefixes is defined which specify powers of 10 which multiply the fundamental units as required for convenient specifications of the numerical quantities. These are given in Table 1.3.

Table ...