A Study Of Hydrodynamic Performance Of Marine Propeller On Variable Parameters

Screw propellers are the most widely used marine propulsive devices at present. The ships are stepping forward to high speed and large-scale by the development of science and technology. With the power increasing of main engines, it is necessary to advance the performance of propellers. Many factors should be considered for obtaining a marine propeller which meet the requirements and possess excellent performance in the process of propeller design, such as efficiency, cavitations, vibration and strength.In the early theoretical research on the performance of propeller, lifting line theory, lifting surface theory and panel method are studied out in turn. But these theories are potential flow theoretical methods based on neglecting viscous effect. With the development of computer technology, CFD is becoming a new theoretical method to predict the hydrodynamic performance of propeller. In this paper, hydrodynamic performance of marine propeller on variable parameters is studied on CFD method using the commercial software Fluent.Firstly, a four-blade skewed propeller on an oil tanker is simulated on numerical method to obtain its thrust coefficients, torque coefficients and open water efficiencies at different advance coefficients. The reliability of CFD method on predicting the open water performance of propeller is verified by comparison the results of Fluent and tests. On the other hand, the influence of different turbulence models to the prediction accuracy is studied. RNG k-ε turbulence model is more suitable for the engineering prediction of open water performance of propeller in the consideration of calculational economic and accuracy.Secondly, the influence of the variable parameter of propeller, such as the rake, pitch of propeller and the camber of blade section, to hydrodynamic performance of propeller is studied. From the results, variation of rake angle has little effect on the hydrodynamic performance of propeller, while the thrust and torque increase with the increasing of pitch and camber. It is an important direction for the optimization design of propeller.Finally, a new six-blade high-skewed propeller is designed. From the numerical calculation results of hydrodynamic performance and finite element analysis, the thrust and torque of the high-skewed propeller is increased, while the open water efficiency decreased, the strength of blades don’t meet the requirement, they should be thicken. At the same time, the influence of different skewed parameters to hydrodynamic performance of propeller is studied and found the law of thrust, torque and open water efficiency changed with the variation of skewed angles.