Which is an advantage of a centrifugal-flow compressor compared to an axial-flow compressor?

• A. Higher peak efficiencies than axial
• B. Small frontal area for given airflow
• C. Straight-through flow with high ram efficiency
• D. High pressure rise per stage

Answer: (D)

A centrifugal-flow compressor delivers a high pressure rise in a single stage by using the impeller to accelerate the air outward and then a diffuser to slow it down, converting velocity into static pressure. This means you can achieve a relatively large pressure increase with one stage, so the overall pressure ratio can be reached with fewer stages than an axial-flow compressor. That per-stage head (pressure gain) advantage is the key reason centrifugal compressors are favored when a compact, high-pressure output is needed.

The other statements aren’t reliable advantages in general. Per-stage efficiency isn’t inherently higher for centrifugal units than for axial ones, and axial compressors are often more efficient at high flow rates. The notion of small frontal area and straight-through flow with high ram efficiency isn’t a defining benefit of centrifugal designs.