3 replies to this topic

[Riaz01]

Why gear box is placed b/w compressor and steam turbine?? what is benefit??

 

Riaz 

[Saml]

Because if you place it on the ends it won't work :-)

 

Now, going to the point. Designing a turbine and a compressor requires a lot of compromises.

You have to select speed, diameter, staging, etc. Sometimes, you can make a design for both compressor and turbine running at the same speed. However, in many cases the optimum design gives you a different speeds. Modifying the design to have the same speed might be flat out impossible or result in an inefficient/expensive design. In this case, installing a gear box (reducer or multiplier) to match the optimum speed of both turbine and compressor is what makes more sense.

[Riaz01]

Thanks for reply.

 

I want to know why some machine compressor and turbine have same speed, and some have placed gear box?? why is advantage and disadvantage?? can any body explain in detail

[Art Montemayor]

Riazo1:

 

There is no "advantage" to employing a gear reducer on a compressor driver.  There is a NEED for the compressor designer/manufacturer to reduce (or at times, increase) the compressor speed.  In those cases, a gear reducer is sometimes employed as you describe.

 

Saml explains very well the application with regards to a centrifugal machine.  I have used gear reducers on reciprocating compressors as well.  You seem to be making the assumption that the gear reducer is employed for gaining an advantage - whether economic or efficiency, I don't know.  But that is not the case.