Simulative Dynamic Performance Analysis of Submarine Diesel Exhaust Deballasting System

Abstract

One dimensional dynamic performance model of submarine diesel exhaust deballasting system is developed. Cross section of outer shell of ballast tank is described as cylinder, one dimensional flow equations combined with webie combustion model and woschni heat transfer model are employed to describe diesels flow characteristic. Coupled effect between gas pressure in ballast tank and discharging performance of diesel is considered in the presenting model. Deballasting duration for one certain submarine model is calculated using the developed model, and the result agrees well with that obtained by using Chinese state code for submarine low pressure system design. For different cross section tank models as circular section model, parabolic section model and trapezoidal section model, dynamic performance of diesel exhaust deballasting system is studied using the validated model. Gas pressure in tank, dropping speed of tank water surface and draft of submarine are simulated, and the results show that little difference of deballasting duration is caused by changing tank cross section. The most stable deballasting process is achieved by using a circular section tank. Deballsting performance is also studied as tonnage of submarine and volume of ballast tank change and commonsense conclusions are obtained.