Loss Sources and Magnitudes in Axial-Flow Compressors

Abstract

A method is presented for calculating the design point efficiency potential of a multistage compressor. Design parameters that affect the efficiency are vector diagram shape, aerodynamic loading level, aspect ratio, solidity, clearances, airfoil maximum and edge thicknesses, annulus area contraction, Mach number, Reynolds number, airfoil surface finish, and part-span shroud placement. Losses associated with off-design operation, blading unsuited to the aerodynamic environment, or poor hardware quality are not considered. The loss model is constructed using rational fluid-dynamic elements, such as boundary layer theory, whenever feasible in an attempt to minimize empirical influences, although some empiricism inevitably enters. The resulting formulation is found to be in satisfactory agreement with multistage compressor experience that covers a wide range of the design parameters.