LIST OF SYMBOLS a af A b C C* D e / FJ h /Z0 H / k L M MJ Axial-flow land width Pad load coefficient Area Circumferential-flow land width Clearance Specific heat Diameter Eccentricity Coefficient of friction Friction on journal Film thickness Minimum film thickness Dimensionless film thickness Mechanical equivalent of heat Permeability Bearing width Rotor mass at bearing Frictional torque on journal
This book is based on an introductory turbomachinery course at Durham University. This course
was taught by Dr David Gregory-Smith and Professor Li He over a number of years and I am extremely
grateful to them for providing a clear and lucid set of principles on which to base this work.
My current colleagues at Durham Dr Rob Dominy and Dr David Sims-Williams have also provided
invaluable help (even if they didn’t realise it!) in preparing this work.
A centrifugal pump is a rotating machine in which flow and pressure are generated
dynamically. The inlet is not walled off from the outlet as is the case with positive dis-
placement pumps,whether they are reciprocating or rotary in configuration. Rather, a cen-
trifugal pump delivers useful energy to the fluid or “pumpage” largely through velocity
changes that occur as this fluid flows through the impeller and the associated fixed pas-
sageways of the pump; that is, it is a “rotodynamic” pump.