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Deterioration of the operational efficiency of radial fans resulting from rotational stalling |
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Deterioration of the operational efficiency of radial fans resulting from rotational stalling Author: S. Fortuna
Large diameter fans, as typically used in the mining and power industries have a considerably narrower range in comparison with fans intended for more general use operational range. The lower limit of the operational range could only attain the limit of hysteresis. This hysteresis is a result of rotating stalling. Rotating stalling is an interesting phenomenon that occurs in both axial and radial rotors. It is still poorly recognised in radial rotors. This stimulated investigations concerning pressure oscillation in streams of airflow, as well as on acoustic levels and flow rates in an attempt to find a means of eliminating the hysteresis set up by the entry vortex consistent with the direction of peripheral velocity. Experiments have confirmed the removal of hysteresis in the condition of forwarded whirl at a vane angle in excess of 30°. Results of tests are described in the paper.
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2011