The engine diffuser is described as divergent and its primary function is to do what to the air?

• A. Divergent, converts kinetic energy to pressure
• B. Convergent, converts pressure to kinetic energy
• C. Divergent, converts pressure to kinetic energy
• D. Convergent, increases velocity

Answer: (A)

The main idea is that the diffuser’s job is to slow the air and raise its pressure before it reaches the compressor. A divergent duct expands the flow area, which reduces the air’s velocity. When the air slows, its kinetic energy is transformed into static pressure energy, increasing the pressure at the diffuser exit. This helps the engine compressor see a steadier, higher pressure inlet.

So the correct description is: the diffuser is divergent and converts kinetic energy to pressure. A convergent duct would speed the air up (converting pressure energy to kinetic energy), which is the opposite of what the diffuser is designed to do.