Impulse turbine stages

[namihabib]

Hi,
I am confused about stages in an impulse turbine.
Generally in industry i have seen that an impulse turbine with single rotor having 2 rows of buckets is called a single stage.(curtis stage)
My concept is that nozzle + rotor is a stage.
if we have one set of nozzles and 3 rotors then it is one stage..
but if we have 2 nozzles & 2 rotors we have 2 stages.am I right?

 

[stgrme]

A Curtis Stage is a special case of an impulse stage. It is designed to be compact and produce a relatively large power output. A Curtis Stage is usually employed as the only stage in mechanical drive turbines (for applications like small pump and compressor drives) or as the control (governing) stage in multi-stage turbines. A Curtis Stage consists of a set of stationary nozzles (nozzle block or nozzle plate), the first rotating row of blades, a row of stationary blades and a second rotating row of blades.

For multi-stage turbines of impulse design, the stages downstream of the control stage will be Rateau Stages. Each Rateau Stage consists of a set of stationary nozzles (diaphragm) and one rotating row of blades.

Best of luck!

 

[JJPellin]

I agree with stgrme with one exception. We have single stage turbines that have a Curtis stage with one stationary set of nozzles, three rotating sets of blades and two reversing rings. The main point I would make is that the stages are not determined by the rotating blades, but by the stationary nozzles. Each set of nozzles defines a stage. The first stage could include one, two or three sets of rotating blades on the same wheel or on separate wheels.

To the OP, you are correct. The diagram you attached would be a single stage.

Johnny Pellin