Fluid Mechanics for Chemical Engineers: with Microfluidics, CFD, and COMSOL Multiphysics 5

Chapter 3. Fluid Friction in Pipes

3.1 Introduction

IN chemical engineering process operations, fluids are typically conveyed through pipelines, in which viscous action—with or without accompanying turbulence—leads to “friction” and a dissipation of useful work into heat. Such friction is normally overcome either by means of the pressure generated by a pump or by the fluid falling under gravity from a higher to a lower elevation. In both instances, it is usually necessary to know what flow rate and velocity can be expected for a given driving force. This topic will now be discussed.

Fig. 3.1 shows a pipe fitted with pressure gauges that record the pressures p₁ and p₂ at the beginning and end of a test section of length L. A horizontal pipe ...