Numerical Research on Establishing Optimum Design Criterion of Ship’s Funnel

Abstract

Exhaust gases of a vessel from a main engine, a diesel generator and an incinerator contain very harmful substances like soot, SO2 and NOx. It is necessary to have the proper design of funnel shape to prevent those harmful exhaust gases influencing on accommodation and a fan room. The exhaust gases are also hot enough to damage electronic devices like radar. Therefore the funnel should be designed in the way that electronic devices are not directly exposed to the exhaust gas. This study provides guidelines for the funnel design to prevent the thermal damage of the electronic devices from the exhaust gases, and to block them re-circulating near accommodation and inflowing into fan room intakes. From CFD analyses, it is certain that the major factors affecting the exhaust gas dispersion are the large scale mixing by separation vortices and the sluggish flow in the recirculation region. And also the standards of the funnel design to minimize the exhaust gas dispersion have been established by adjusting the funnel shape, the position of the exhaust pipe, the shape of bulwark, the exhaust direction of air ventilated an engine room and the angle of the exhaust pipe.