ABSTRACT
As opposed to radial compressors, axial compressors are most suitable for high flow rates as required in aircraft engines. The compression process proceeds in stages, as each stage produces a limited pressure rise due to adverse pressure gradients. The thermodynamics of flow are analyzed using the Mollier diagram, and the definitions of degree of reaction and blade loading and flow coefficients are revisited in the contest of axial compressors. The difference between stage efficiency and adiabatic compressor efficiency are discussed next, and it is shown that the adiabatic compressor efficiency is less than the stage efficiency, in contrast to axial flow turbines. The concept of the “work done factor” which arises due to the adverse pressure gradient is explained briefly. The chapter ends with design features for axial flow compressors.
