I read that the velocity of the air is increased at the nozzle guide vanes of a turbine before it actually hits the turbine blades, then compresses, and the process repeats. My question is, what’s the reasoning behind this? The way I’m thinking of it is like this:
Let’s compare compressed air to a sumo wrestler.
And then let’s compare just a normal guy.
If the sumo wrestler (compressed air) runs at you with a somewhat slow speed, he’ll apply a lot of force to you, but if a normal guy runs at you with a much faster speed, you’ll feel a lot of force too. I’m wondering where the logic is behind this, because can’t the same force be applied both as compressed air and sped up air if both mass and velocity contribute to momentum?
Thanks
In: 1
Okay, first we need to clarify some things. Not all the blades in a gas turbine engine are “turbine blades”. Only the blades in the actual turbine section are referred to as such. The blades in the compressor section are compressor blades. Based on your question, I am assuming you are asking about ambient air entering the compressor section, and not exhaust gas entering the turbine section.
The compressor section compresses ambient air by first accelerating it and then decelerating it. The rotor blades accelerate the air, and then the stator blades slow it down, increasing pressure. As the air moves through the compressor, the cross-sectional area decreases in order to maintain an ideal Mach number.
Inlet guide vanes are used in multi-stage axial compressors to help manage the flow and allow for higher compression ratios than would otherwise be possible.
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