The main use of the inlet duct in the compressor is to convert:

• A. Kinetic energy to pressure
• B. Pressure to kinetic energy
• C. Chemical energy to electrical energy
• D. Heat to energy

Answer: (A)

The inlet duct mainly acts as a diffuser, decelerating the incoming air before it reaches the compressor. By slowing the flow, the air’s kinetic energy is converted into static pressure, raising the pressure at the compressor face. This helps deliver a steady, high-pressure air mass flow and improves compressor performance and stability. The other options describe energy conversions that don’t occur here: the duct does not turn pressure into kinetic energy, nor does it convert chemical energy to electrical energy, or heat into usable energy in this context.