Which statement about the diffuser action of the compressor stators is true?

Which statement about the diffuser action of the compressor stators is true?

• A. Decrease velocity and increase pressure
• B. Increase velocity and decrease pressure
• C. Increase velocity and increase pressure
• D. Decrease pressure and velocity

Answer: (A)

The diffuser action of the compressor stators is about turning kinetic energy into pressure energy. As air leaves the rotor, it is moving fast and has lower static pressure. The stator vanes guide and slow the flow, increasing its cross-sectional area effectively and converting velocity (dynamic pressure) into static pressure. That deceleration raises static pressure for the next stage and helps improve overall pressure recovery, while keeping losses manageable. So the statement that best describes this action is that velocity decreases and pressure increases. If flow were to speed up in a diffuser, that would be the opposite of what a diffuser does (more like a nozzle), and if both decreased or both increased, it wouldn’t reflect the diffuser’s role of slowing the flow to raise pressure.

The diffuser action of the compressor stators is about turning kinetic energy into pressure energy. As air leaves the rotor, it is moving fast and has lower static pressure. The stator vanes guide and slow the flow, increasing its cross-sectional area effectively and converting velocity (dynamic pressure) into static pressure. That deceleration raises static pressure for the next stage and helps improve overall pressure recovery, while keeping losses manageable.

So the statement that best describes this action is that velocity decreases and pressure increases. If flow were to speed up in a diffuser, that would be the opposite of what a diffuser does (more like a nozzle), and if both decreased or both increased, it wouldn’t reflect the diffuser’s role of slowing the flow to raise pressure.