ABSTRACT
A fluid machine is a device either for converting the energy held by a fluid into mechanical energy or vice versa. This chapter describes the internal workings of a number of different designs of fluid machine. It is concerned with the basic principles of mechanics of fluids that are brought into play, and starts by introducing the main categories of fluid machines. The initial mechanical movement is a reciprocating one the term engine or motor is used. Although a great variety of fluid machines is to be found, any machine may be placed in one of two categories: the positive-displacement group or the rotodynamic group. The functioning of a positive-displacement machine derives essentially from changes of the volume occupied by the fluid within the machine. All rotodynamic machines have a rotor, that is, a rotating part through which the fluid passes. Reciprocating pumps and positive-displacement pumps are most suitable for low rates of flow and particularly for high pressures.
