Rotodynamic pump

A rotodynamic pump is a kinetic machine in which energy is continuously imparted to the pumped fluid by means of a rotating impeller, propeller, or rotor, in contrast to a positive-displacement pump in which a fluid is moved by trapping a fixed amount of fluid and forcing the trapped volume into the pump's discharge.^[1] Examples of rotodynamic pumps include adding kinetic energy to a fluid such as by using a centrifugal pump to increase fluid velocity or pressure.^[2][3]

Introduction

A pump is a mechanical device generally used for raising liquid from a lower level to higher one. This is achieved by creating a low pressure at the inlet and high pressure at the outlet of the pump. Due to low inlet pressure, the liquid rises from where it is to be stored or supplied. However, work has to be done by a prime mover to enable it to impart mechanical energy to the liquid which ultimately converts into pressure energy.^[4]

Considering the basic principle of operation, pumps can be classified into two categories:

1. Positive-displacement pumps.
2. Non-positive-displacement pumps.