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The box can be quite small or it may be quite large and you can get in there and comfortably walk around. It may be aircooled, it may be watercooled, depends upon the design. It will have a control oil system installed nearby. Quite often the control oil system tank will be mounted directly underneath the turbine, so in this section here where my mouse is. And then well have several pumps that we use in order that we can pump the control oil around the system and well use it to actuate valves and move actuation pistons, etc. The gas turbine itself is relatively simple in terms of concept, although there is a lot of engineering that goes into it. We draw the air in on the left, you can see where the air is being drawn in, its indicated in blue. You can see our central shaft as well, its this item here. Thats going to connect to our generator. We draw the air in, it flows past a series of compressor blades and were going to increase the pressure as the air moves across each of these blades. And remember that each row of blades is called a stage. So at every stage, as we move from left to right, were going to increase the air pressure and correspondingly the temperature as well. For heavy frame gas turbine designs, youll be looking at compression ratios of about 15, maybe up to 18 to 1. So from here on the left, over to here, all the way on the right where my mouse is, where the air is discharged, the compression ratio will be up to 18 to 1. With aeroderivative engines, its actually higher. It might be 30 to 1. Those types of gas turbine are more focused on generating thrust compared to the heavy frame design where were focused on generating electrical power, or at least that is our end goal. Aircrafts require thrust in order to stay up in the air. Power plants require as much power as possible in order to be profitable. So we take the air, its discharged through these two channels, and then we reach our combustion zone. Were going to inject fuel into this space. The fuel is going to be injected here. We ignite the fuel, we get combustion, we get heat, and we use the heat to heat up the air. We go up to the top here. You can also have a look from the top. You can see the fuel lines coming along here, the mouses also along here, and along here, and the two on the bottom. And that fuel then is going to be sprayed and discharged into the combustion space. Initially, were going to need to have a spark in order to ignite the fuel. But once the gas turbine is up to speed, typically beyond 50, the temperature of the air is enough that we can keep combustion constant and we dont need any external ignition source, for example, from a spark plug or similar. The hot air thats being heated is then going to be discharged through nozzles, through these here. The nozzles are stationary. And we pass the hot air across the blades of our turbine. Lets see, here is one set, heres the next set, and here is the next set. Those turbine blades will rotate, the central shaft will rotate, and we can connect the central shaft to the generator to generate electricity. When we discharge the hot air at this end here, it may be 500, maybe 550, 600 degrees Celsius in extreme cases. And thats quite a lot of energy that were going to discharge just potentially straight to atmosphere out through this hole. So rather than do that, what we can do instead is connect the gas turbine to a steam system. This will increase the overall plant efficiency. Here is a combined cycle power plant. We call it a combined cycle power plant because gas turbines use whats called the Brayton cycle. The Brayton cycle is a type of thermodynamic cycle. The other type of cycle that youll see when looking at steam turbines is the Rankine cycle. Each of these cycles is named after the person who invented them. In engineering, youll also see the Otto thermodynamic cycle and the diesel thermodynamic cycle. Theyre all just describing different types of thermodynamic process. Because were using a gas turbine that is housed within this box here, and the steam turbine is housed over here, within one type of power plant, were essentially using a Brayton cycle and the Rankine cycle together. And thats why we call this type of power plant a combined cycle power plant. Very briefly, Ill explain to you how it works. Weve got our gas turbine here. It connects on a shaft to a generator, which is housed within this box. And then we have three phases of power, which are coming out here. They join to a transformer, and then we send that electrical power to our consumers. We draw air in through these levers here, and the air will pass through a series of filters before it gets to our gas turbine. We filter the air because we dont want any foreign particles being sucked into the turbine because that might damage our compressor blades.