Research On Hydrodynamic Performances Of Full-revolving Propulsors

Full-revolving propulsor which rotates around the axis 360 degrees can get the maximal propulsive force at any direction. It can make the vessel in situ rotate, move along cross direction, fastness retropulsion, operate the rudder at a minifiactional arrange and so on. Installing the full-revolving propulsor can simplify the stern' shape, reduce resistance, and when something breakdown the whole machine can be moved out of the cabin without entering into the dock which can increase the oil engine's life length. This new type propeller which fit for various vessels such as tugboat, float lifting boat, excavating boat, ferry boat, flat bottom boat and so on has extensive market prospect and military purpose.This dissertation used numerical and model experimental methods to do some research on its hydrodynamic performance theoretically and testily. Calculated full-revolving propulsor's steady and unsteady hydrodynamic performances and also did some experiments on that.There are three kinds of full-revolving propulsor now, such as pull-type, push-type and pair propeller-type. Used panel method to establish the steady and unsteady calculation model, and also compile the corresponding FORTRAN program. The influence between propeller's lifting panel method and cabin and bracket's Hess-Smith method was done by iterative calculation.The calculation and experimental results of the three types full-revolving propulsor are so anastomotic that can prove the numerical method was effective and accuracy. On the basic of that, also found out that because of pod's blocking action the pull-type, push-type propeller's load increased; pod and bracket produced a high wake region at its rigging ahead and back.Installing the fin to some kind full-revolving propulsor's cabin, calculated its hydrodynamic performance and the compared the result with that without fin so as to analysis the fin's influence on it. Also analyzed the wake region's variation by comparing the fin-cabin's wake distribution and the one without fin's.This dissertation adopted CFD software FLUENT and steady numerical method to research the full-revolving propulsor's hydrodynamic performance in stern wake's field, for the stern wake made great influence on its performance and maneuverability. Used FLUENT to simulate the wake at the disk, and then took the circumferential average as the inlet. Compare the drag, moment and efficiency in wake and unwaked condition, the propeller's drag and moment were all increased, the efficiency curve also had some change.Predicting the navigation performance, judging the ship-engine- propeller' adaption and whether the velocity is satisfactory by the model experiment. Getting the main propeller 'normal cavitation character, induced impulsive pressure at the stern and noise grade by the corresponding experiments, so as to judge if the vessel superficial' pressure is satisfactory. Accomplished the open water test of the full-revolving unit device. With the optimization rudder and propeller, self-propelled experiment was done to determine the interacting parameter between the rudder and propeller. The 3-D stern wake field experiment at the speed of 18kn and the main propeller' cavitation in normal navigation werr calculated. The matching condition of the ship-engine-propeller by model experiment were predicted.The model experiments on some type full-revolving propeller were done to get the open water performance and its hydrodynamic character at different angles of deflection. Measured the left propeller' character when it was back swing 180. and 90. in sailing ahead and deviation to right.Based on the unsteady calculation method, the full-revolving propulsor' hydrodynamic performance in uniform flow was calculated, and the cabin's actual effect and nominal wake. the full-revolving propeller's unsteady performance in such two wakes were calculated. The performance when different wake components were ignored were calculated, so as to analysis the action of the wakes. Calculated full-revolving propulsor unsteady performance in tested stern wake flow, and talked about the influence between the wake and the propeller's unsteady performance.