| Recently, the energy problem is becoming more and more serious with industrialprogress. Energy saving technologies are much accounted of in every walk of life.The International Marine Organization (IMO) is speeding up the process of carryingout Green-shipbuilding, and provides a series of energy index, such as EEDI etc.On this background,30.8w DWT VLCC is used as the main object in this paper,and various numerical simulation research is carried out on one of the energy savingdevice-stern duct. In this paper, the influence of duct on wake field, ship resistanceand power of self-propulsion in general has been studied.Firstly, for cases of E779A propeller and30.8w DWT VLCC propeller, researchon numerical simulation method of open-water performance was carried out.Influence of grid, computational zone, pressure discrete scheme, and convergenceprocess on results was studied. And open-water calculation method with highprecision was developed, by which the difference of computational and experimentalKt, Kqand η0are below2.5%in the range of common-used advance coefficient.Secondly, resistance and wake calculation have done for30.8w DWT VLCCnaked and with duck separately, and the result of wake goes well with the experiment.For the design and installation of stern duct in this paper, after carefully investigatingthe influence on the speed and powering of ship, it turns out there is no good effect toimprove the wake equality, but produces pre-swirl effect by interfering withbilge-vortex.Finally, the ship-propeller-rudder interaction calculation was performed in thispaper. Influence of Several different circumferential locations of propeller on the shipresistance and propeller thrust and torque was studied with and without duct by steadymethod. It shows that the duct has improved the propulsive performance of30.8wDWT VLCC. Besides adopting general power prediction method from model test, anew way of considering the pre-swirl effect was introduced to make the comparison. |
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