Investigation of Flow Phenomena and Improvement of Drain Course in Ship Ballast Tank Based on Two Phase Flow Model

Abstract

　The efficiency of the ballast water drainage system affects the profitability of shipping companies when loading and unloading. Moreover, the arrangement of the ballast system is closely related to the tank structure, which affects the component production and structural strength of ship. However, there is no mature design and evaluation method to balance the relationship between drainage efficiency and tank structure.

　This study utilizes hydraulic experiments and computational fluid dynamics (CFD) methods to verify the flow phenomenon during the drainage process in the ballast tank, so as to discuss the drainage efficiency. The model designed for the experiment data collection is a part of ballast tanks of a typical bulk carrier with the scale of 1:10. The experimental results are then validated and verified by conducting a two-phase flow model based on the volume of fluid (VOF) simulation. The research follows the order from simple to complex, starting from the single-arranged small-scale tank, and gradually expanding to the complex large-scale model. Therefore, the VOF method has been recognized in the ballast tank drainage simulation, and based on the simulation results, the drain course to improve the drainage efficiency is proposed. The results provide the reference for the design and improvement of the ballast system.