Hydrodynamic Performance Of Bionic POD Propulsion

In recent years, with the increasingly serious of marine territory problem, the protectionof marine territory has become a hot topic. Many scholars devote into advanced navalequipment research and forwardly appeal to develop and strengthen the navy. The bionic podpropeller can be used for the development of stealth ship, military reconnaissance equipment,submarine weapon research, etc. Combined with the propulsion type of double bionichydrofoil pendulum and the concept of pod propulsion, a new type of bionic pod propulsion isdesigned, which has low noise, high stability, high mobility, flexibility installation and use,etc, and which is suitable for underwater or surface navigation vessels which drive in specialenvironment, such as mining area, narrow corner, algae intensive area, etc. At the beginningof the hydrodynamic performance study of flapping hydrofoil, the motive power drivemechanism and the shape design of pod are studied, and finally the hydrodynamicperformance prediction of the bionic pod propeller is completed.Firstly, the motion mode is defined that oscillating bar makes hydrofoil flap. And themovement rule and parameter definition of flapping hydrofoil are given. Based on the2-Dhydrofoil numerically computation of flapping hydrofoil’s new motion mode, flappinghydrofoil flow field characteristics are given, and different motion parameters (such asfrequency, phase difference, hydrofoil amplitude, oscillating bar length, flow velocity),different advance coefficient, Strouhal number influence on the hydrofoil hydrodynamicperformance of flapping hydrofoil.Secondly, based on the2-D hydrodynamic performance study of single flappinghydrofoil,2-D double symmetrical flapping hydrofoils are numerically calculated, and whichflow field characteristics are analyzed in detail. The distance influences on2-D doublesymmetrical flapping hydrofoils of hydrodynamic performance are analyzed with the differentphase difference. By comparing double symmetrical flapping hydrofoils with single flappinghydrofoil, the calculating result can be captured that the double symmetrical flappinghydrofoils can increase the average thrust coefficient and average moment coefficient, but ithas weak impact on propulsive efficiency.Thirdly, the propulsion drive mechanism and overall appearance of bionic pod propelleris preliminarily designed. Bionic pod propeller adopts gear drive and crank rocker mechanism to transfer motor torque into hydrofoil’s symmetrical flap. Pod is mainly composed ofcylindrical column and large disc hull.Finally, the hydrodynamic performance prediction of bionic pod propeller is completed.Reach a conclusion that the pod has beneficial effects on double symmetrical flappinghydrofoils, and makes the average thrust coefficient, average moment coefficient, propulsiveefficiency of double symmetrical flapping hydrofoils increase. The performance curve ofbionic pod propeller corresponding is obtained.Bionic pod propeller has agile arrangement, high maneuvering, low noise, goodreliability, etc. And it has the special military application prospect.