From Power Generation Handbook: Selection, Applications, Operation, and Maintenance


When compared with axial compressors, centrifugal compressors have the following five advantages:

  1. They occupy a smaller length than the equivalent axial compressors.

  2. They are not liable to loss of performance by buildup of deposits on the surfaces of the air channel when working in a contaminated atmosphere.

  3. They are able to operate efficiently over a wider range of mass flow at any particular rotational speed (i.e., they alleviate problems of matching operational conditions with those of the associated turbine).

  4. They are used mainly in small power units because the higher isentropic efficiency of axial compressors cannot be maintained for small machines.

  5. Titanium is the preferable material because of its high resistance to corrosion.

Principle of Operation

The centrifugal compressor consists of a stationary casing containing a rotating impeller, which increases the velocity of the air, and a number of diffusers that decelerate the air converting a part of its kinetic energy to pressure. Figure 11.1 illustrates a centrifugal compressor.

Figure 11.1: Diagrammatic sketches of centrifugal compressors. ( a) Impeller and diffuser of a centrifugal compressor; ( b) impeller of a centrifugal compressor; ( c) different compeller of a centrifugal compressor; ( d) impeller shroud.

Compressor Characteristics

Figure 11.2 illustrates the variation in the pressure ratio when a valve placed in the delivery line of the compressor running at constant speed is slowly opened. When the valve is shut and the flow is zero, the pressure ratio will have...

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Products & Services
Impellers are rotating devices that force liquids, gases and vapors in a desired direction. They are widely used in pumping, blowing, and mixing applications.
Air Compressors
Air compressors are machines that compress air to higher than atmospheric pressures for delivery to pneumatic or robotic tools, industrial equipment, or direct-use applications.
Gas Compressors and Gas Compressor Systems
Gas compressors and gas compressor systems are used to circulate gas through a process, enhance conditions for chemical reactions, provide inert gas for safety or control systems, recover and recompress process gas, and maintain correct pressure levels by either adding and removing gas or vapors from a process system.
Turbine Pumps
Turbine pumps are centrifugal pumps that use pressure in combination with a rotary mechanism to transfer fluid.  They typically employ blade geometry, which causes fluid circulation around the vanes to add pressure from inlet to outlet. 
Centrifugal Pumps
Centrifugal pumps consist of a set of rotating vanes, enclosed within a housing or casing, that are used to impart energy to a fluid through centrifugal force.

Topics of Interest

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Overview From a historical viewpoint, the centrifugal compressor configuration was developed and used well before axial-flow compressors, even in the propulsion field. The common belief that such a...

5.8 Centrifugal Compressors As the name implies, a centrifugal compressor achieves part of the compression process by causing the fluid to move outward in the centrifugal force field produced by the...

OVERVIEW Centrifugal compressors are used extensively because of their smooth operation, large tolerance of process fluctuations, and their higher reliability compared to other types of compressors.

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