A Critical Review of Stall Control Techniques in Industrial Fans
Figure 4
The effect of a pressure pulse on a tunnel ventilation fan. Industrial fan designers have historically assumed that a fan runs up and down its characteristic in the presence of a pressure pulse (black symbols). Unsteady computational results for both a positive and negative pressure pulse indicate that the fan’s operating point departs from its steady state characteristic during the transient associated with a pressure pulse (red and blue symbols). This departure results in unsteady aerodynamic forces increasing by a factor of two compared to those associated with operation of the fan at its duty point [47].