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A gas
turbine is a rotary machine, similar in principle to
a steam turbine. It consists of three main
components - a compressor, a combustion chamber and
a turbine. The air after being compressed into the
compressor is heated either by directly burning fuel
in it or by burning fuel externally in a heat
exchanger. The heated air with or without products
of combustion is expanded in a turbine resulting in
work output, a substantial part, about two-thirds,
of which is used to drive the compressor. The rest,
about one-third, is available as useful work output.
A gas turbine
extracts energy from a flow of hot gas produced by
combustion of gas or fuel oil in a stream of
compressed air. It has an upstream air compressor
(radial or axial flow) mechanically coupled to a
downstream turbine and a combustion chamber in
between. "Gas turbine" may also refer to just the
turbine element.
Energy is released when compressed air is mixed with
fuel and ignited in the combustor. The resulting
gases are directed over the turbine's blades,
spinning the turbine, and mechanically powering the
compressor. Finally, the gases are passed through a
nozzle, generating additional thrust by accelerating
the hot exhaust gases by expansion back to
atmospheric pressure.
Energy is extracted in the form of shaft power,
compressed air and thrust, in any combination, and
used to power aircraft, trains, ships, electrical
generators, and even tanks. |
