送風機のサージングに関する実験的研究(第1報) : 管路内の気柱の自由振動

概要

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The phenomena of surging of a blower is the self-excited vibration of air colum in the pipeline. To obtain a fundamental understanding of the vibrating air column, free vibrations are studied experimentally. The influence of the valve, the opening, and the blower are also tested. The results : 1. The values of natural frequencies calculated on the basis of the acoustic theory hold sufficient accuracy even for a pipe-line of large scale. 2. When the amplitude of pressure variation is small (about 150 mm Aq.), a valve inserted into the pipe has little effect on natural frequency even if the opening ratio is about 0.1. 3. When either the valve or the blower is in the pipe-line, the damping ratio of vibration of air column increases with the amplitude. 4. The damping effect of an opening on any mode of vibration of air column is the greatest, when its position coincides with a node of the mode.
1957-01-25