In the dual axial-flow or twin-spool compressor system, the first stage turbine drives the

In the dual axial-flow or twin-spool compressor system, the first stage turbine drives the

• A. N(2) compressor
• B. N(1) compressor
• C. Both N(1) and N(2) compressors
• D. Neither compressor

Answer: (A)

In a twin-spool (dual axial-flow) engine, two separate rotating systems are used: a low‑pressure spool (N1) and a high‑pressure spool (N2), each driven by its own turbine. The low‑pressure turbine turns the low‑pressure spool to drive the fan and LP compressor. The high‑pressure turbine turns the high‑pressure spool to drive the HPC. The first stage of the high‑pressure turbine is the stage that provides the energy to drive the high‑pressure compressor, so it powers the N2 compressor. The N1 compressor is driven by the low‑pressure turbine, not by the first stage of the high‑pressure turbine.

In a twin-spool (dual axial-flow) engine, two separate rotating systems are used: a low‑pressure spool (N1) and a high‑pressure spool (N2), each driven by its own turbine. The low‑pressure turbine turns the low‑pressure spool to drive the fan and LP compressor. The high‑pressure turbine turns the high‑pressure spool to drive the HPC. The first stage of the high‑pressure turbine is the stage that provides the energy to drive the high‑pressure compressor, so it powers the N2 compressor. The N1 compressor is driven by the low‑pressure turbine, not by the first stage of the high‑pressure turbine.