In a dual-rotor axial flow compressor, which rotor is driven by the first stage turbine?

In a dual-rotor axial flow compressor, which rotor is driven by the first stage turbine?

• A. N-2
• B. N-1
• C. Both
• D. None

Answer: (A)

In a dual-rotor axial flow compressor, two rotors are on separate shafts so each can be powered by its own turbine stage. The first turbine stage is connected to the front (outer) rotor, which in this system is labeled N-2. Air encounters the N-2 rotor first, then passes to the rear rotor N-1 for additional compression, with the second turbine stage driving that rear rotor. So the rotor energized by the first stage turbine is the N-2 rotor. The other rotor (N-1) is driven by the subsequent turbine stage.

In a dual-rotor axial flow compressor, two rotors are on separate shafts so each can be powered by its own turbine stage. The first turbine stage is connected to the front (outer) rotor, which in this system is labeled N-2. Air encounters the N-2 rotor first, then passes to the rear rotor N-1 for additional compression, with the second turbine stage driving that rear rotor. So the rotor energized by the first stage turbine is the N-2 rotor. The other rotor (N-1) is driven by the subsequent turbine stage.