Gas turbines are used in many situations to generate circular motion from moving gases. Common uses are in power stations as part of an electricity generation process and in jet engines.

Mechanical Structure

Gas turbines can be thought of as a set of concentric disks, that is they all spin around the same central shaft. The disks get gradually bigger as they get further away from the gas inlet. Each disk is a ring of aerodynamic blades. All the disks are contained with in a structure that directs the gas through the blades. The motion of the gas from inlet to outlet through the blades puts a torque(turning force) on the shaft.

Fluid dynamics

The gas enters the turbine at high pressure. As it passes through the turbine it transfers energy to the blades and so the shaft. This loss of energy causes a loss of pressure and reduced temperature in the outlet gas.

Steam Turbines in Power Stations

Steam Turbines are used in power stations to turn a shaft that provides the rotation needed by the generator. It is common to have more than one turbine all on the same shaft. In many cases turbines are double sided with the steam entering at the centre and moving in both directions along the shaft. This is the same as two ordinary turbines back to back with the inlet in the middle and an outlet at both ends.