Editing Compressor (section)

====Axial compressors====
[[File:Axial compressor.gif|thumb|right|An animation of an axial compressor.]]
{{main|Axial compressor}}
'''Axial compressors''' are dynamic rotating compressors that use arrays of fan-like [[airfoil]]s to progressively compress a fluid. They are used where high flow rates or a compact design are required.

The arrays of airfoils are set in rows, usually as pairs: one rotating and one stationary. The rotating airfoils, also known as blades or ''rotors'', accelerate the fluid. The stationary airfoils, also known as ''stators'' or vanes, decelerate and redirect the flow direction of the fluid, preparing it for the rotor blades of the next stage.<ref name=Perry /> Axial compressors are almost always multi-staged, with the cross-sectional area of the gas passage diminishing along the compressor to maintain an optimum axial [[Mach number]]. Beyond about 5 stages or a 4:1 design pressure ratio a compressor will not function unless fitted with features such as stationary vanes with variable angles (known as variable inlet guide vanes and variable stators), the ability to allow some air to escape part-way along the compressor (known as interstage bleed) and being split into more than one rotating assembly (known as twin spools, for example).

Axial compressors can have high efficiencies; around 90% [[polytropic]] at their design conditions. However, they are relatively expensive, requiring a large number of components, tight tolerances and high quality materials. Axial compressors are used in medium to large [[gas turbine]] engines, natural gas pumping stations, and some chemical plants.