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The gas–liquid streams in valve columns are likely to surge at low gas velocities, which degrades tray performances and threatens production safety. Therefore, the gas–liquid surging mechanism and vibration properties were investigated in this article. First, the theory of gas–liquid unstable flow at the seal point was proposed based on the principle of lowest energy. Then, the evolution mechanism, gas–liquid flow characteristics, and essential condition of surging are proposed. Meanwhile, experiments were carried out in a Φ580 mm valve column; the frequency spectral and hydraulic characteristics of surging were in accordance with the expected surging mechanism. Moreover, the surging vanish point criterion and safe operating superficial gas velocity for valve columns were advanced. Finally, fundamental models for surging frequency and amplitude were established. The models are in close accordance with the experimental data, which suggests that they could accurately describe the surging behavior.

According to the sonofluorescence principle of ultrasonic cavitation oxidation suggested by the authors [Huamao Li et al., Acta Acust. 22 (1997)], the cavitation field distribution images in both analogous symmetrical and nonsymmetrical sonochemical reactors filled with aqueous Luminol–KOH alkaline solution have been taken when using an ultrasound with an operating frequency of 1.45 MHz and an ultrasonic electric power of 25 W. The images seem to show that the ultrasonic cavitation field in the analogous symmetrical sonochemical reactor appear symmetrical with uniform distribution, and the ultrasonic cavitation fields in the analogous nonsymmetrical sonochemical reactors appear nonsymmetrical with nonuniform distribution, but the nonsymmetrical cavitation field distribution can be guided along some curved way. The authors think that the sonofluorescence image method can be available for use in a sonochemical reactor designed for getting uniform or positioning cavitation field. [Work supported by the Natural Science Foundation of Jiangxi province and the Science Foundation of Ji’an Teachers’ College.]

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