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now this is a frame 5 gas turbine, its about 14000 kilowatts, and it works like this
to start it up it uses a starting motor or turbine, to rotate the shaft of the turbine
The shaft of the turbine is here
This part is a compressor
This few stages is the turbine, all in one shaft
and out the end comes a coupling where you put your generator, compressor, or whatever you want to drive
the gas turbine, once it's up to speed, the air comes in
through the inlet hood, normally there would be a silencer up here
the air goes in and turns and goes past stationary and rotating blades of the compressor
the pressure goes from atmospheric and goes up to about (8 times the pressure)
keeps on going here, reverse flows around the combustion chamber
the combustion chamber have 10 of them around, the fuel is fed into a fuel nozzle
and the fire is here, the combustion chamber is cooled by the air around the outside and the inside gets heated and the temperature at this point here
on todays machines, about 2000 up to 2300 F, goes through these stages, it cools it down and takes the energy out that goes into the shaft
and goes out out here through the exhaust casing, through this diffusor and then on out and here would also be a silencer to reduce noise to the surroundings
the whole thing is built on a big I beam about 8 feet wide, and in here is lube oil tanks
and coolers and pumps that put the lubercation for the barings, the baring here, and the baring there
here are valves that take fuel flow and regulate it through the pressure, that the machine needs. it needs quite low pressure once you fire it to begin with, and you need to control that flow so you get the right temperatures
because otherwise you will burn up the hot parts, so there is a control panel
that tells the fuel system valves what to do, once it has started and gotten up to speed there is a governor
governor sits here on the shaft and knows what the speed is, and knows what speed you want and adjusts the fuel flow accordingly, once you are up to speed and get the generator, that's what it is
snychronized, get it online, then you put more and more fuel. Now you cannot change the speed anymore, but you can put more and more fuel in, and the torque increases
and the generator over here would generate more and more Kilowatts.
to not exceed the designed temperatures in these hot parts in here are temperature detectors that go to the control panel and then in turn cuts the fuel down to the amount that is correct, the max for the machine, that is how it works
When the machine hs been up by the starting means to about 20 percent speed, then it is ready to fire, and it is fired by spark plugs on a couple of combustion chambers,
and in between each combustion chamber, these 10 chambers, is a cross fire tube, and so when a chamber with a spark plug inside sees it
the pressure rises and the flame goes through the cross fire tube to the next one over and propagates all around
in addition to the ignition the ignitor here, is a flame detector, as soon as the flame detector sees the flame it says cut back. because we do not want to have the amount of fuel needed for firing to continue.
we would like to avoid heat shock, you want to cut it down to about half and you leave it there at what we call warm up.
the spark plugs are out of the picture because they are pressure ejected out of the way, as the flame detector keeps on sensing what is going on, and it's always tricky to make sure that we don't cut the fuel back too far
if we cut back too far the flame will go out and the flame detector enters protection and says hey! shut down again. Normally that doesn't happen, if it does we must shut down
otherwise we put fuel in, and no fire and pretty soon we have an explosion. so each flame detector is a very important part of the starting cycle. after the warm up for a couple of minutes, then control panel says stop putting fuel in.
in the mean time a little more fuel, the starting means still trying to get it up, and now the turbine helps start the machine, between the two of them it brings it up to about 70 percent speed.
at that point the clutch between the starting means and the shaft uncouples. the starting means shuts down, and the turbine accelerates up to the full speed point
then the control system takes over and governs the speed from that point on.