Internal Flow Analysis of FPU Oil Separator Considering Six Degrees-of-Freedom Ship Movement

摘要

A practical sloshing analysis for a top side equipment of a FPU (Floating Production Unit) is presented considering six degrees of freedom of motion for the FPU. Since a FPU has various kinds of oil separator, it is important to stabilize the free surface level of the fluid filled in the oil separator tank in order to produce of crude oil without interruption. In the present work, the effect of the floating body motion on the free surface in the tank is investigated. The motion of FPU is calculated according to the three dimensional panel method. The motion response in the frequency domain is converted to the time domain by inverse Fourier transform. The six-DOF motion of the FPU is used as a time variant boundary condition in the CFD analysis. The internal flow is assumed as laminar for the sake of the concise computation. The VOF model with geometrical reconstruction is applied for simulating the free surface in the tank. The first order of upwinding and time marching scheme are used. To evaluate the free surface level in the tank, the distance between the tank bottom and the free surface in a specified position is picked up. From the analysis, it is concluded that the effect of the floating body motion could be negligible in a sloshing point of view under the given ocean environmental condition.