How Gas Turbine Generators Work

Purpose

• Gas turbine generators are also known as combustion turbines as their purpose is to draw energy from a flow of continuously combusting gas. At present, gas turbine generators have one of the highest power-to-weight ratios in the world. This means that--for their size--they can produce the most mechanical energy. Their uses are many, and they come in all sizes and variations. Among the first ever to be produced were the turbines for jet-propelled aircraft. From there, they have been used as secondary electricity generators aboard aircraft, sources of energy on both maritime and naval military vessels, tanks, and even concept cars and motorcycles used to set and break land speed records.
  
  

Structure

• There are three main chambers to most gas turbine generator designs. There is the compressor, the combustion area and the turbines. The compressor is an open cylinder at one end which contains a series of fan blades attached around a central spindle. The combustion area has a ring of fuel injectors surrounding it, which leads into an inverted cone-shaped device called a candle holder. The candle holder is filled with perforations, like a colander. The turbines are almost identical to the compressor, being another series of fan blades attached to the same spindle.
  
  

Function

• Though it is actually in the middle of the generator, the combustion area is the first to start functioning. The candle holder contains a continuously lit fire which ignites fuel from the fuel injectors and the surrounding air. Because of the way the generator is shaped, this combustion serves to pull more air in through the compressor and force the compressor blades to turn. Slowly, the blades speed up as more fuel is burnt, increasing the compressor's rate of air intake to such a degree that the air pressure it contains can often be 30 times that of the surroundings. The air shoots through the compressor at speeds in excess of several hundred miles an hour at full burn, passing through the combustion chamber and into the turbines. The turbines, spinning as fast as they are because of the air passing through, generate thousands of pounds worth of thrust for jet flight. Also, if the generator is stationary, the spindle connecting the compressor through to the turbine may also be carried on to a friction generator and battery to create electricity.