Abstract

Although accidental bunker oil spills at seaway are relatively rare events, they can be pose real threat to the natural marine environment. One of the reasons for the bunker spill to occur is a design failure; one of the ways it can demonstrate is an improper location or height of vent heads, leading to a bunker oil discharge during heavy rolling, due to sloshing phenomenon. Design of a ship and her systems is guided by various formal conventions and ensuing requirements by classification societies, as a result of past experience and background knowledge. Nevertheless, the requirements are not always fully effective and up to date. An example of such situation is an accidental spill from a deep bunker tank, that has been arranged and designed according to the valid rules and regulations, however not accounting for dynamic physical phenomena that when occur lead to discharging the fuel through the vent. Therefore, the contemporary regulation of vent arrangement for some specific bunker tanks design options seems insufficient and requires scientific insight. To this end, we propose science-based regulatory framework modification. This is done through examining the location of the deep tank vent with regard to dynamics of the oil sloshing phenomenon, adopting CFD-based approach that is suitable for the purpose of onboard tank design. Moreover, an experimental validation of numerical simulations outcome is presented which makes the study credible. The proposed approach is both scientifically valid and practically feasible. Some CFD simulations of liquid sloshing need to be carried out for certain bunker tank design options. The additional burden at the design stage is not significantly time consuming thus remains justified, especially nowadays when CFD has become an industrial standard in some branches. The proposed solution attempts to improve the contemporary regulations in the area of bunker oil overflow prevention, reducing the negative impact of maritime transportation on the environmental safety.

Citations

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