How does a centrifugal compressor differ from an axial-flow compressor?

Centrifugal and axial-flow compressors differ significantly in their design, operation, and performance capabilities within gas-turbine engines.

Centrifugal Compressors

These devices use a high-speed impeller to increase the kinetic energy of the gas, which is then converted into pressure within a divergent passage known as a diffuser. While they are relatively simple and inexpensive to manufacture, they are limited to lower pressure ratios and are primarily used today in small industrial units.12

Axial-Flow Compressors

In these units, gas flows parallel to the axis of rotation through multiple rows of aerodynamically shaped blades. As the gas passes through, its velocity is alternately increased and decreased; the kinetic energy gained during velocity increases is converted into pressure during the subsequent decreases.1

Key distinctions include:
* Efficiency: Axial-flow compressors offer higher efficiencies than centrifugal models, making them the standard for jet aircraft engines.21
* Complexity: Because they handle only small pressure increases per stage, axial-flow compressors require many stages to achieve high overall pressure ratios, often necessitating complex "spooled" shaft designs.2
* Operation: Axial-flow designs are highly sensitive to flow separation and "stalling," requiring precise aerodynamic blade design to maintain efficiency.2