Optimasi Preliminer pada Desain Propeller Wageningen B-Screw Series dengan Menggunakan Metode Multi Objective Optimization
Propulsion system is one of ship systems which require more attention, especially on propeller design. Propeller design will have a serious impact on ship performance because the propeller greatly affects the ship speed. As a matter of KCR 60M (high speed missile vessel), where the service speed that is requires by the owner is 28 knots while at sea trial the service speed was not reached which was only 27 knots. The slight speed difference has a big impact on the company where the ship were built. The company will get a penalty due to time delay of delivery because they have to solve the problem within a certain time period. The amount of the penalty fee reached up to 2.5% of ship price per day. On the other hand the designers do not have much time to do research on propeller designs which are able to provide optimal performance due to another work deadlines that must be completed. Therefore there are many shipbuilding companies turn over the propeller design to outsourcings with the aim of removing the failure risk to them. From this problem, this study will discuss about preliminary optimization method of KCR 60M propeller design, especially by using the Wageningen B-screw series propeller with the multiobjective optimization method. The propeller that will be optimized is expected to be able to have maximum value of thrust coefficient (KT) and efficiency (η). The optimization is done to each propeller number start with Z=3 up to Z=6. The population of design space was obtained after running the optimization program. The final optimal design parameter was taken using crowding distance technique and the result for each propeller number are respectively Z=3 (B3-787, B3-314, B3-560), Z=4 (B4-478, B3-308, B3-428), Z=5 (B5-416, B5-501, B5-476), and Z=6 (B6-570, B6-727, B6-709. Computational Fluid Dynamics analysis (CFD) was done to obtained the thrust value of each propeller model. The final optimum design is obtained from Z=5 population run-3 with smallest MSE value.