Procedure for noise reduction for a turbo machine using a Phase shift/Phase superposition and method for execution of this procedure

The noise produced on a blower by the interaction of moving blades (1) with fixed blades downstream may be reduced by injecting compressed air jets (14) upstream of the moving blades. The compressed air is taken from the primary flow (12) and fed to a ring (10) with as many holes (11) as there are fixed blades. A motor (15) allows the ring to be rotated to find a position where the sound generated is in phase opposition to the interblade noise Independent claims are made for equipment which uses the method of counteracting interblade noise