Numerical investigation of plume dispersion characteristics for various ambient flow velocities

Abstract

Floating LNG bunkering offshore terminal (FLBT) has been adopted as a floating unit by the marine industry equipped with the natural gas liquefaction plant on the ship’s deck with the practical interest in controlling the plume emission discharged from the ship. The downwash of emitted plumes has adverse consequences on the ship’s engine intake and ventilation system followed by the interference of the smoke with helicopter operations. Owing to this fact, understanding of the plume behavior is considered to be so significant in the aspect of ship design and thereby, flow visualization techniques assist to study the plume path ensuring the safety of the personnel and functioning system. The unignited flare gas emitted from the tower invites heat transfer due to the temperature difference between the atmospheric wind and the ship’s exhaust, which follows the examination of mixing enhancement of fluid mediums as well as the mitigation of plume concentration depending upon wind speeds. The parametric study is intended to investigate the plume dispersion pattern around a ship based on the flare motion and bending angle for light and strong wind speeds. It is observed that the plume gas rises higher and disperses over the larger area with wider streamline separation due to the effect of buoyancy for light wind speeds. On the other hand, the motion of flare gas is found to be narrow for strong winds restricting vertical movements due to dominant inertial forces than gravity pull. Thus, the current numerical investigation facilitates in understanding the configuration and plume distribution by the variation in streamline behavior with contours plots. In this work, the calculated results are analyzed systematically in pretty realistic conditions and simple measures are obtained, which will be applied to the preliminary design of plume stack depending on the ship’s deck arrangement.