Turbomachinery, in mechanical engineering, describes machines that transfer energy between a rotor and a fluid, including both turbines and compressors. While a turbine transfers energy from a fluid to a rotor, a compressor transfers energy from a rotor to a fluid.

These two types of machines are governed by the same basic relationships including Newton’s second Law of Motion and Euler’s pump and turbine equation for compressible fluids. Centrifugal pumps are also turbomachines that transfer energy from a rotor to a fluid, usually a liquid, while turbines and compressors usually work with a gas.

·         A turbomachine is basically a rotating machine

·         The rotating wheel is called a rotor / runner / impeller

·         The rotor will be immersed in a fluid continuum

·         The fluid medium can be gas / steam / water / air

·         Energy transfer takes place either

Ø  From rotor to fluid, or

Ø  From fluid to rotor

Turbomachine – Definition

Any device that extracts energy from or imparts energy to a continuously moving stream of fluid can be called a turbomachine. Elaborating, a turbomachine is a power or head generating machine which employs the dynamic action of a rotating element, the rotor; the action of the rotor changes the energy level of the continuously flowing fluid through the machine. Turbines, compressors and fans are all members of this family of machines.

In contrast to positive displacement machines (particularly of the reciprocating type which are low speed machines based on the mechanical and volumetric efficiency considerations), the majority of turbomachines run at comparatively higher speeds without any mechanical problems and volumetric efficiency close to one hundred percent.

·         A turbomachine is a device where A turbomachine is a device where mechanical energy in the form mechanical energy in the form of shaft work, is transferred either to or from a continuously flowing fluid by the dynamic action of rotating blade rows.

·         The interaction between the fluid and the turbomachine blades also results in fluid dynamic lift.

A turbomachine produces change in enthalpy of the fluid passing through it.