A Comparison of Axial and Centrifugal Compressor Gas Turbines: An Objective Examination of the Pros and Cons of a Much Debated Subject

THE first gas turbine propelled aircraft in this country were the result of Whittle's classic conception using a single‐stage centrifugal compressor. On the other hand the German turbo‐jets had, without exception, multi‐stage axial compressors. The two types are shown diagrammatically in FIG. 1 and the outstanding differences are apparent at a glance. The centrifugal is short and of large diameter and the air flow through the compressor is turned from the axial direction to the radial and then back to the axial. On the other hand, the axial compressor derives its name from the substantially unidirectional flow of the air. It is of relatively small diameter, but much longer because of its many stages, each stage consisting of a large number of moving blades and an equal number of fixed blades. Altogether there may be between one thousand and two thousand individual blades in the compressor. It is from these contrasting features that much argument has arisen.