Siemens SGT-600


Thread Starter


Hi Gents,

I have a simple question regarding Siemens gas turbine SGT-600.

What is the principle of operation for the IGV (Inlet guide vane) and what is the main function of that valve?

Best regards,
Hi Gent,

Unfortunately, we don't seem to have a lot of contributors with Siemens GT experience.

Most heavy duty gas turbines use variable inlet guide vanes to control the amount of air entering the axial compressor. This is usually done to protect the axial compressor during starting and shutdown (at speeds below rated), and is also done to improve combustion at lower fuel flows/loads. The IGVs (they are usually a set of variable vanes located at the inlet to the axial compressor) can also be used to maximize exhaust temperature for gas turbines used for combined cycle application (where the GT exhaust is used to produce steam for a steam turbine or some other process/application).

Some units with combustors designed to limit air polluting emissions also use the IGVs to control air flow so as to maintain stable combustion over a wider operating range.

So, the function of the IGVs (there are effectively a control valve, but one with many variable "orifices") is to control or limit air flow through the axial compressor, and hence through the gas turbine and exhaust. They can be used for other purposes, as well. They are not usually ever fully closed (blocking all air flow), nor fully open--but that would depend on the manufacturer's designs.

Hope this helps!