Research On The Disturber Design And Vibration Control Of The Chemical Column

When a chemical column is exposed to the wind flow with a certain wind speed, aparticular vortex street is formed in the wake, which leads to the vibration of thecolumn in the across-wind direction. So it is desirable to research on disturbersspecially designed for columns in order to reduce the damage of wind-inducedvibration.This paper probes into the anti-vibration principle of the disturbers based on thetheory of mechanical vibration and vortex-induced vibration. The structures of thesound disturber and airstream disturber are designed to be: excitation source, controlsystem and the launcher. Wind tunnel experiments are set up to study the effect of thedisturbers on the wind-induced vibration of the columns. Experiments concerning thewind-induced vibration of the cases with and without disturbers are conducted and thevibration characteristics are obtained. It is found that the disturbers cause theboundary layer around the column to separate earlier, the vortex shedding frequencyto reduce and the wind-induced vibration amplitude to reduce.To further analyze the effect of the disturbers, an ANSYS-CFX fluid structureinteractional numerical model based on LES is established and contrastive analysis fornumerical results as well as wind tunnel experimental results are launched to examinethe predictive accuracy of numerical model. Wind-induced vibration is reduced as thenumber and the installation height of the disturbers increase. Six groups of disturberswith the installation height range of above4/5column height, the fluctuation velocityrange of0.75~1.30times the first critical velocity, the fluctuation frequencyapproaching the frequency of the unstable separated boundary layer are effective toreduce the wind-induced vibration.When the angle between the installation point and the upstream stagnation pointis fixed at90°, the fluctuation velocity equals to the first critical velocity, and thefluctuation frequency equals to the calculated value based on the empirical formulasuggested by Prasad&Williamson, the disturbers are the most effective. Andmulti-group disturbers with an intersection angle of60°are more effective than asingle group. Conclusion can be drawn after the simulations about the vibrationcontrol of three columns with varied slenderness ratios that the disturbers designed in this paper are suitable for the wind-induced vibration control of different columns.Researches in this paper provide foundations for the design and application of thedisturbers in column.