The N2 compressor consists of how many stages and is connected to which turbine?

• A. 10 stages; 2 stage high pressure turbine
• B. 8 stages; 3 stage low pressure turbine
• C. 12 stages; 1 stage high pressure turbine
• D. 9 stages; 2 stage high pressure turbine

Answer: (A)

In a two-spool gas turbine, N2 is the high-pressure compressor on the HP spool, and it is driven by the high-pressure turbine. The number of stages in the HP compressor is set by the engine design, and 10 stages is a common training example for the HP compressor. The high-pressure turbine that drives it is often two-stage in this configuration, providing the necessary shaft power without being overly large.

So, the description of 10 stages for the N2 compressor and a two-stage high-pressure turbine aligns with how the HP spool typically units together, making it the best-fit configuration. The other options mix in low-pressure turbine connections or different stage counts that don't match this HP-spool arrangement.