Numerical Prediction Of Propeller Sheet Cavitation And Analysis Of The Effect Of Propeller Parameters On Its Cavitation Performance

Cavitation on marine propellers may be unavoidable due to the demand of heavily loaded propellers required in recent years. Accurate prediction of the cavitation extent on blade is very important in the design of propellers, working in nonuniform flows.The paper adopts perturbation potential based surface panel method to predict sheet cavitation on marine propellers, working at uniform inflow or nonuniform inflow conditions. The termination model is assumed by pressure recovery law and the detachment is specified at the leading edge of the blade. More complete 3-D boundary conditions for cavity flow are applied and the cavity extent is iterated and determined independently by the thickness at the end of cavity, which make the program more robust and faster convergence.The validation studies of a 5600 TEU container ship propeller, a standard propeller model PC456 of CSSRC and an INSEAN propeller model E779 A for steady cavitating flow are presented, and the calculation results of cavitation extent are in good agreement with the experimental data. The cavitation flow of 5600 TEU propeller is also simulated at unsteady flow condition, and the results are acceptable compared with the experiment observation.In this paper, effects of some parameters such as skew, rake distribution and blade sections on propeller cavitation performance are studied both for steady and unsteady cases. The two cases show the similar results that with the skew increasing, the cavity extent will decrease. The blade section has strong effect on its cavitation performance and optimal blade section design can obviously achieve better cavitation performance.Tip rake distribution curvature to pressure side can decrease the cavity extent near the tip region and thus can reduce the fluctuating pressure induced by propeller cavitation.