A turbine blade is a radial aerofoil mounted in the rim of a turbine disc and which produces a tangential force which rotates a turbine rotor. Each turbine disc has many blades. As such they are used in gas turbine engines and steam turbines. The blades are responsible for extracting energy from the high temperature, high pressure gas produced by the combustor. The turbine blades are often the limiting component of gas turbines. To survive in this difficult environment, turbine blades often use exotic materials like superalloys and many different methods of cooling that can be categorized as internal and external cooling, and thermal barrier coatings. Blade fatigue is a major source of failure in steam turbines and gas turbines. Fatigue is caused by the stress induced by vibration and resonance within the operating range of machinery. To protect blades from these high dynamic stresses, friction dampers are used.
Turbine blade from a Turbo-Union RB199 jet engine. This is a blade with an outer shroud which prevents gas leaking round the blade tip in which case it wouldn't contribute to the force on the aerofoil. The platform at the base of the aerofoil forms a continuous annulus ring which, together with cooling-air cavity purge flow prevents hot gas leakage onto the turbine discs. The short extension, or shank, between the platform and fir-tree fixing in the disc allows space for cooling-air entry to blade, may control blade vibration modes and heat transfer to disc rim.
The turbine blades have a golden colour in this engine cutaway.
A turbine blade with thermal barrier coating. This blade has no tip shroud so tip leakage is controlled by the clearance between the tip and a stationary shroud ring attached to the turbine case.
Laser-drilled holes permit film cooling in this first-stage V2500 nozzle guide vane
A gas turbine, gas turbine engine, or also known by its old name internal combustion turbine, is a type of continuous flow internal combustion engine. The main parts common to all gas turbine engines form the power-producing part and are, in the direction of flow:a rotating gas compressor
a combustor
a compressor-driving turbine.
Sketch of John Barber's gas turbine, from his patent
typical axial-flow gas turbine turbojet, the J85, sectioned for display. Flow is left to right, multistage compressor on left, combustion chambers center, two-stage turbine on right
An LM6000 in an electrical power plant application
Gateway Generating Station, a combined-cycle gas-fired power station in California, uses two GE 7F.04 combustion turbines to burn natural gas.