How are turbine blades attached to turbine discs?
Each of the turbine blades used in a steam turbine has a blade root 4 formed in a complex shape, and is attached to the turbine rotor by engaging the blade root 4 in a blade groove (or a disc slot in the turbine rotor) 5 having a shape complementary to that of the blade root 4.
What do you call where the blade is attached to the turbine?
Wind turbines consist of the blades attached to a hub, which is jointly called the rotor. The rotor is connected to a the nacelle, and the nacelle holds the key electrical and mechanical equipment at the top of the tower including the main shaft, gearbox and generator.
How do turbine blades rotate?
By using aerodynamically designed blades, the speed of the blades creates a negative pressure on the curved surface of the blades, thereby sucking the blade into rotation, in the same way the negative pressure on the top surface of aircraft wings keeps the aircraft in the air.
How is the turbine disk attached to turbine shaft?
The methods of connecting the shaft to the turbine disk vary. In one method, the shaft is welded to the disk, which has a butt or protrusion provided for the joint. Another method is by bolting. This method requires that the shaft have a hub that fits a machined surface on the disk face.
How are rotor blades attached to disk type rotors?
A series of grooves or notches, conforming to the blade root design, are broached in the rim of the disk. These grooves allow attachment of the turbine blades to the disk; at the same time, space is provided by the notches for thermal expansion of the disk.
What is a nacelle used for?
The nacelle of a wind turbine houses the drive train and other tower-top components. It sits on top of a yaw bearing that allows it to rotate as the wind direction changes. The nacelle must be accessible for maintenance and repair work. Access is usually via a lift and ladders within the tower.
What is a hub in a wind turbine?
Rotor Hubs. The rotor hub is the component that usually holds the blades and connects them to the main shaft of the wind machine. It is a key component not only because it holds the blades in their proper position for maximum aerodynamic efficiency, it also rotates to drive the generator.
What is the turbine rotation?
Large-scale turbines typically rotate at 20 rpm, while domestic sized turbines tend to revolve at roughly 400 rpm. In most large-scale turbines, the low speed shaft is connected to a gearbox. The gearbox increases the rotational speed of the shaft, up to 1200-1800 rpm.
What causes turbine to spin?
Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.
What is a blade in a turbine?
A turbine blade is the individual component which makes up the turbine section of a gas turbine or steam turbine. 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.
What are the four main types of turbines?
While turbines can be classed as either impulse or reaction according to the way they function, there are four broad types of turbines categorized according to the fluid that supplies the driving force: steam, gas, water, or wind.
What is a turbine disk?
The drum or the disc to which the turbine blades are attached. It is forged and then machined with an integral shaft or flange onto which the shaft may be bolted. To limit the effect of heat conduction from the turbine blades to the disc, a flow of cooling air is passed across both sides of each disc.
What is hub in wind turbine?
What is rotor in turbine?
The rotor connects to the generator, either directly (if it’s a direct drive turbine) or through a shaft and a series of gears (a gearbox) that speed up the rotation and allow for a physically smaller generator. This translation of aerodynamic force to rotation of a generator creates electricity.
What causes the turbines to spin?
Wind turbines work on a simple principle: instead of using electricity to make wind—like a fan—wind turbines use wind to make electricity. Wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, which creates electricity.
How are wind turbine blades made?
Turbine blades are made by heating a mix of glass or carbon fibres and sticky epoxy resin, which combines the materials, providing a strong light-weight composite material, but which also make it hard to separate the original materials for recycling.
What is a curved-blade disc turbine?
Curved-blade disc turbines such as that shown in Figure 8.25 generate primarily radial flow, similar to the Rushton turbine. However, changing the shape of the blades has a significant effect on the impeller power requirements and gas-handling characteristics.
What are the different parts of a turbine blade?
A turbine blade is inserted in a slot of a disc mounted on a rotating shaft, as shown in Figure 3.40 schematically. The blade can be divided into four parts: airfoil, platform, shank, and dovetail.
What are the excitations of a turbine blade?
More subtle excitations come from the non-uniformity of nozzle spacing, obstacles upstream and downstream of the blade row and non-uniformities due to connections into or out of the machine. Flow instability can also provide an excitation for compressors and for longer turbine blades (typically in the last stages of condensing machines).
What is the purpose of a turbo blade?
Turbine blades contain rows of hollow aerofoils for cooling to increase the engine operating temperature. Turbine blades are not normally a problem. However when troubles do occur they can be difficult to cure. This is partly because the rotating blades are exposed to quite high steady stresses.