Based On CFD Method To Research The Hydrodynamic Performance Of Transverse Thrusters

Transverse thrusters are widely used in ship and marine engineering especially inmanoeuvring aids, but the difference from propeller is that as a standard component deviceof dynamic positioning system, the study on hydrodynamic performance of transversethrusters is not sufficient. In the design and calculation, it mainly uses the rated thrustprovided by manufacturers or modified design of ducted propeller. Thus, it can’t reflect thetrue flow field, thrust structure, ship impact and can not compare the efficiency. So thehydrodynamic performance analysis of transverse thrusters is of both fundamental andapplied significance.In order to study the hydrodynamic performance of transverse thrusters, by using CFDmethod, the hydrodynamic performance of transverse thrusters with ship speed and bowthrusters is studied. The simulation and verification of thrusters with a four-leaf Ka-typecontrollable pitch propeller are compared with experimental data and good agreement isobtained. Average error is less than5%.In the no ship speed condition, the effects of pitch ratio, expanded area ratio, boss ratio,tunnel length, wall inclination and tip clearance are observed on the performance of thetransverse thrusters. The results show that pitch ratio, boss ratio and tip clearance have bigeffect on the performance; the tilt angle of the bow sides near the transverse thruster hassome effecet on the performance; tunnel length and expanded area ratio have only a littleeffect on the performance.The performance of bow thrusters has a strong dependence of their effectiveness onthe bow and ship speed. In order to accurately analyze the flow field around the thrusters, abow equipped by a thruster designed by NAPA is used to calculate the performance of bowthrusters with and without ship speed. After studying the change of performance underdifferent ship speeds, the thrusters’ failure mechanism is discussed. The result proves thattransverse thrusters are at the most effective when the vessel is stationary and the thrusterstend to lose effectiveness as the vessel increase its ahead. But the presence of ship speedwill increase the thrust and torque of the inner propeller. The reason of thrusters’ failure layto the pressure of the bow decreasing rapidly and reversing which balance out the thrustproduced by the inner propeller.