Effect of Orientation on Two-phase Slug Flow Induced Vibrations

Multiphase flow induced vibrations is a serious safety issue in oil and gas industries due to its undesirable vibration. Currently, there is a lack of usable data that could help to predict the magnitude of multiphase flow induced vibration in pipe inclined at various angles. The objective of this paper is to determine the magnitude of vibration in two-phase flow in pipe at inclination angle of 0°, 30°, 45°, 60°, and 90°. Air to water superficial velocity ratio of 1.25 was selected for this purpose because it is the value that causes the flow to change abruptly from slug to churn flow and vice versa, depending on the orientation angle. The flow conduit is selected to be a stainless-steel pipe with an internal diameter of 52.5 mm (2 inches). The vibrations are monitored at the pipe section of length 38D from the inlet. Maximum longitudinal vibrations were observed in 0° orientation. 60° encountered the maximum amplitude vibrational frequency in transverse direction but being at a higher frequency. The suggested model can be used to evaluate the FSI impact of unstable vibrations for any piping orientation and diameter.