Rabu, 22 Februari 2012

How The Turbine Works

There are different types of Turbines:
1. Steam Turbine
You may have heard of a steam turbine. The majority of power plants using coal, natural gas, oil or nuclear reactor to create steam. Steam flowing through the large turbines and carefully designed multi-stage to rotate the output shaft that drives a generator factory.

2. Water Turbine
Hydroelectric dams use water turbines in the same way to generate power. Turbines used in hydroelectric plants look very different from the steam turbine because water is so much denser (and slower moving) than steam, but the same principles.

3. Wind Turbine
Wind turbines, also known as wind mills, using the wind as their motive force. A wind turbine does not look like a steam turbine or water turbine because the wind moves slowly and is very light, but again, the principle is the same.

4. Gas Turbine
A gas turbine is an extension of the same concept. In a gas turbine, a pressurized gas spins the turbine. In all modern gas turbine engine, the engine produces its own pressurized gas, and it does this by burning something like propane, natural gasoline, gas or jet fuel. The heat comes from burning fuel expands air, and high-speed rush of hot air spins the turbine.

In this blog I will discuss more in depth Gas Turbine:
How The Turbine Works pict

Parts of Gas Turbines:
Gas turbine engines are, theoretically, very simple. They have three parts:
Compressor - compresses the incoming air to high pressure.
Area of ​​Combustion - the burning of fuel and produces high-pressure gas, high speed.

Turbine - extracts energy from the high-pressure, high velocity gas flowing from the combustion chamber.

In this engine, the air sucked in from the right by the compressor. The compressor is basically a cone-shaped cylinder with small fan blades attached in rows (eight rows of blades are represented here). Assuming a light blue air at normal air pressure, so as air is forced through the compression stage its pressure increased significantly. On some machines, the air pressure can be increased by a factor of 30. High-pressure air from the compressor is shown in dark blue.

Gas Turbine Fuel Spaces:

How The Turbine Works pict

High pressure air then enters the combustion area, where the ring flow fuel injectors inject fuel. Fuel is generally kerosene, jet fuel, propane or natural gas. If you think about how easy it is to blow the candles out, then you can see the problem in the design of the combustion area - entering this area of high pressure air moving at hundreds of miles per hour. You want to keep the fire burning continuously in the environment. Part of solving this problem is called "people with fire."
The injectors are on the right. Compressed air entering through perforations. Flue gas exit on the left. You can see the previous image that a second set of cylinders wraps around the inner and outer perforated can, guiding the compressed intake air into the perforations.

How The Turbine Works pict

On the left side of the machine is part of the turbine. In this picture there are two sets of turbines. The first set of direct drive compressors. Turbine and compressor shaft all turn as one unit:
On the far left is the final turbine stage, shown here with a set of rotor blades. This makes the output shaft. The final stage turbine and output shaft unit, completely independent freewheeling. They spin freely without any connection to the rest of the machine. And it is an amazing part of the gas turbine engine - there is enough energy in the hot gas blowing through the blades of a turbine to produce the final output 1500 horsepower.
All of this area into a major technical problem due to tremendous temperatures, pressures and levels of spins on the machine. In the case of a tank or a turbine used in power plants, in fact nothing to do with the exhaust gases but vent them through an exhaust pipe, as shown. Sometimes the exhaust will go through some type of heat exchanger for extracting heat for other purposes or to preheat the air before it enters the combustion chamber.

Gas Turbine with a Variation  (Turbo fan and Turbo prop):
How The Turbine Works pict
Large jet aircraft using what is known as a turbofan engine, which is nothing more than a gas turbine combined with a large fan in front of the machine. Here is the layout (very simple) basic turbofan engines:
You can see that the core of the turbofan gas turbine engine as explained in the previous section. The difference is that the final stages of the turbine drive shaft that makes its way back to the front of the engine to an electric fan
The purpose of the fan is to dramatically increase the amount of air moving through the machine, and therefore increase the engine thrust. Fan moving air is called "bypass air" (shown in the purple) because it passes through the turbine engine and move straight to the back of the nacelle at high speed to provide thrust.

How The Turbine Works pict

A similar turboprop engine turbofan, but has a conventional propeller at the front of the machine. Connected to the gearbox output shaft to reduce speed, and output of the propeller gearbox.