Abstract
Stall stagnation phenomena in the system of axial-flow compressors and ducts are studied on the basis of analytical
results. The stall stagnation boundary was found to be formed mainly by two zones, B- and A-boundaries in the first and
second reports of this study. The B-boundary tends to occur for plenum-type delivery ducts with fat and very short configuration. The A-boundary tends to occur for narrow and long delivery ducts in the case of relatively short suction ducts. The
boundaries were found in the second report to be given by definite values of the relative duct lengths normalized by the resonance wave length and the effective plenum area ratios.
In this third report, it is found that, for the B boundary and the A boundary, the reduced frequencies with respect to the
suction duct length and the delivery duct length, respectively, appear to have definite values. It means that the fluid movements thereabout affect the stagnation in addition to the effect of the acoustical-geometrical conditions.
