Large-Eddy Simulations of Flow Induced Vibrations in a Vacuum Flasher Unit

Large-eddy simulations of flow through a vacuum flasher are conducted to study unsteady flow dynamics and resulting flow-induced vibrations. The objective of this study is to isolate energetic vibrational modes encountered in the vessel, and also study the effect of a “Vibration Reducer” (VR), which is found to be highly effective in practice. An energetic mode at 3 Hz is found to exist in tile overhead lines coming out of the dome of the flasher vessel. These simulations show that by placing the VR, a perforated pipe, in tile dome region, the amplitude of the 3 Hz mode can be reduced by a factor of 5, provided that the effective open area of the VR is optimized. In addition, by stabilizing the flow, these simulations predict that the VR also decreases the overall pressure drop by 35%.