A centrifugal compressor is a type of dynamic compressor, or turbocompressor, with a radial design. Unlike displacement compressors that work at a constant flow, dynamic compressors work at a constant pressure and the performance is affected by external conditions such as changes in inlet temperatures.
So, how does a centrifugal compressor work?
Air is drawn into the center of a rotating impeller with radial blades and is pushed toward the center by centrifugal force. This radial movement of air results in a pressure rise and the generation of kinetic energy. Before the air is led into the center of the impeller, the kinetic energy is also converted into pressure by passing through a diffuser and volute.
Each stage takes up a part of the overall pressure rise of the compressor unit. Depending on the pressure required for the application, a number of stages can be arranged in a series to achieve a higher pressure. This type of multi-stage application is often used in the oil and gas and process industries. Alternately, in wastewater treatment plants, low pressure, single-stage applications are used to achieve the desired pressure ratio.
In modern configurations of centrifugal air compressors, ultra-high speed electric motors are used to drive the impellers. This results in a compact compressor without a gearbox and associated oil-lubrication system, thus making it oil-free and appropriate for applications that require 100 percent oil-free air