CFD modeling of flow induced vibration mechanism in sea water piping on a regasification terminal platform

Abstract

Vibration is a common problem in water piping system, particularly when it involves multiple elbows. One of the sources of vibration is the turbulent flow in the system. The objective of this project paper is to investigate the mechanisms that leads to excessive vibration in the sea water discharge piping experienced on floating LNG platform. The model is developed to simulate the actual conditions experienced at the platform. The simulations were done using selected turbulent models, because the Reynolds’s Number at any condition within the operating envelope is more than 4000. Upon completion of the simulations, focus on excitation at the wall is critical to be done. The major mechanism of vibration is pressure difference within the fluid flow. Thus, pressure and wall shear stress acting along the pipe wall need to be analyzed to pin point whether there is any mechanism at work which will induce vibration. The results show large pressure difference was observed between the inner and outer elbows thus prompting high inclination to vibration. It was observed that higher fluctuations of velocity and pressure near the wall as the Reynolds’s number increases. The amplitudes of the fluctuations for both pressure and velocity were seen to be close to linear in nature.