With the continuously rising fuel price and the increasingly stricter Energy Efficiency Design Index (EEDI) regulations, the development of energy saving devices has become a kind of fashion in past few years. Meanwhile, higher demands of structural strength requirements for installing the energy saving devices have also caught worldwide attentions. The present work aims to design and develop an energy saving rudder-bulb-fin combination for a 208,000 DWT bulk carrier. The rudder with twisted leading edge is designed according to the inflow angle that can prevent the occurrence of cavitation and hence to reduce fuel consumption. A streamlined shape bulb is designed for bridging the gap between rudder and propeller hub which eliminates hub vortices and also retrieves energy from the propeller slipstream. A pair of horizontal fins mounted on the rudder bulb is designed to recover the energy loss from rotational turbulent flow and gain extra thrust to improve propulsive efficiency. Computational Fluid Dynamics technique is employed to optimize the design of the rudder-bulb-fin combination. The simulation shows that the designed twisted rudder with rudder bulb was found to have 1–2% power saving than using a conventional rudder with a straight-lined leading edge. With the addition of fins on the rudder, another 1.3% power saving has been proved by the model tests. To further assess the strength characteristic of fins, finite element (FEM) analysis is adopted to model the stress distribution on fin surfaces. The FEM analysis shows that the maximum von Mises stress is found at the girders and larger stress components are around the connection of fin and rudder, however, all these stress are under the yield strength of the steel and well handled by the design engineers.
Design and Development of the Energy Saving Rudder-bulb-fin Combination by Using Computational Fluid Dynamics Technique
Lecture Notes in Civil Engineering
Practical Design of Ships and Other Floating Structures ; 2019 ; Yokohama, Japan September 22, 2019 - September 26, 2019
2020-10-06
13 pages
Article/Chapter (Book)
Electronic Resource
English