Regelung der Kompressoren

Noise generation in vane axial fans due to rotating stall and surge

“…†. Eckert and Schnell [8] and Schultz [9], who studied the generation of blade stall in an axial compressor and axial pumps, found that stall can occur within a part of, or even within entire channels of, the blade row.…”

“…The discrete frequency of the peak, corresponding to the one or two cell stalls, depends on the speed of rotation of the stall cells. This speed depends on the geometry, speed and load of the fan and is, in general, within 10± 90 per cent of the rotational frequency [10], the lower values being valid for the more intensive stalling [8]. The real values for the rotational frequencies of the stall cells for the fans discussed were established experimentally.…”

“…Experiments have shown that, at the inception of stall, two independent rotating stall cells appear on the suction side of the blade: at the blade root (A) and at the blade tip (B) (Fig. 2a) [8,9]. These two stall cells are a consequence of throttling and of increase in the angle of attack,¯.…”