Hydrodynamic Causes of Vibration in the Pipe Bend of Process Pipelines

Hydrodynamic vibrations can occur both in pump piping at local resistances and in the pump, for example, when it’s operated outside the working area. Vibrations occurring in the hydraulic section of the pumps and associated pipings are transmitted to the mechanical section and can lead to breakdowns. Oscillations of pump piping can be caused by both hydrodynamic reasons and vortex formation at local resistances, and resonance with the natural frequencies of the piping. In some cases, the vibration of pipelines exceeds the permissible norms by 1.5-2 times. The range of vibration frequencies of a hydrodynamic nature directly depends on the flow rate of the working medium. As the latter decreases, the range also decreases. In any elbow of the pipeline, with a sufficient flow rate of the liquid, vortex formation occurs, which is the cause of forced vibrations. The values of the Strouhal number characterizing hydrodynamic phenomena in unsteady flow regimes for the flow of liquids in local resistances of pipelines have been studied very little.