What are the two basic types of compressors?

• A. Centrifugal and radial.
• B. Axial-flow and centrifugal-flow.
• C. Axial-flow and mixed-flow.
• D. Radial-flow and axial-flow.

Answer: (B)

Compressors in gas turbine engines are categorized into axial-flow and centrifugal-flow types. In an axial-flow compressor, air moves along the engine axis and is compressed progressively through multiple rotor–stator stages, giving high flow and high overall pressure rise—an arrangement favored in large, high-speed engines for efficiency and capacity. In a centrifugal-flow compressor, air enters an impeller and is flung outward by centrifugal force, then directed through a diffuser to convert velocity into pressure; this design is compact, rugged, and works well as a booster or in smaller engines, though it typically handles lower flow with moderate pressure ratios per stage. Other terms like radial-flow describe the same centrifugal concept, and mixed-flow isn’t a primary separate class, so axial-flow and centrifugal-flow are the two fundamental compressor types.