Inlet Distortion Effects in Axial Compressors

Although uniform inlet conditions are highly desirable and system designers attempt to insure distortion-free flow entering compressors, situations frequently arise in which substantial total pressure, velocity, and angle variations exist at the compressor inlet. Aircraft gas turbines are particularly prone to inlet distortion problems due to changes in aircraft attitude and the effect of the airframe on the inlet flow conditions, but industrial insallations may also suffer from inlet distortion in cases where poorly designed bends have been installed upstream of the compressor. In this paper, problems associated with inlet distortion are discussed and some of the simpler techniques for analyzing the effects of circumferential inlet distortion are presented.