A Study on Design Investigation Method for Drainage Plan in Ship’s Ballast Tanks by Hydraulic Model Experiment

Abstract

　The performance of ballast water drainage systems has a significant impact on the profitability of shipping companies. Furthermore, the arrangement of the ballast system is closely related to the tank structure, affecting the production of ship components and structural strength. However, the current state is that the design knowledge and assessment method are mainly based on the experience of the designer, and the ambiguity of design factors makes it difficult to make definite design principle.

　This study uses hydraulic model experiments to analyze the complex flow phenomena in ballast tanks to provide design strategy for improving the drainage efficiency. The tank model design refers to a part of the ballast tank of a Panamax bulk carrier at a 1/10th scale, and some detailed structures are appropriately simplified. The hydraulic experiments are carried out from the small-scale ballast tank to clarify the flow phenomena between compartments, and further analysis for the impact of the drainage path on the drainage efficiency. Based on this study, a design policy for the drain course is established and verified in the hydraulic experiments based on the multi-compartment ballast tank model. The experiment results are compared with the case of the ballast tank model applying conventional design methods, and the effectiveness of the drain course is confirmed. This study provides the reference for the design and improvement of the ballast tanks design.