In a centrifugal flow compressor, where is the air pushed after acceleration?

• A. Into diffuser, which increases pressure
• B. Back to inlet
• C. Into combustion chamber
• D. Out through exhaust

Answer: (A)

After acceleration in the impeller, air exits with high velocity and relatively low static pressure. It is pushed into the diffuser, whose expanding geometry slows the flow and converts that kinetic energy into static pressure, raising the pressure for the next stage or the combustion chamber. This diffusion process is how the compressor builds pressure. Returning air to the inlet would waste energy, and sending air straight to the combustion chamber or exhaust would bypass the needed pressure rise.