Design Of Propulsion System For Autonomous Underwater Vehicle Considering Wake Field

Autonomous underwater vehicle has been widely used in many areas such as the seabed resource exploration,marine environmental survey,marine engineering and marine defense,etc.Then many ocean phenomena have the character of large scale,which requires the ocean monitoring system has the abilities to observe the ocean environment and collect the parameters of the ocean environment in real time,large scale and long range.However,AUV just can carry limited energy,which restricts its enhancement of range,thus reducing the resistance of its shape and increasing the efficiency of propulsion system becomes the direct way to enhance the range of AUV.In this paper,a optimized low-resistance AUV's shape is got,and according to the structure of the flow field around AUV,a proper and high efficient properller for AUV based on the lifting line theory has been designed.Finally,the performance of the propeller is stimulated and the option about how to choose a suitable motor for propeller is also proposed.The exact outcomes are as follows.1.The shell model of autonomous underwater vehicle is optimizied.In combination of engeneering practice,the resistance iterative optimization algorithm is given for the good performance and high volume ratio Myring shape.The optimized low-resistance shape and the trend of resistance varied with shape parameters are obtained through iterating resistance in the theory of optimization.After CFD simulation,the final shape model is established and the final resistance is got.2.According to circumfluence theory,a high efficiency propeller is designed.A method about how to choose the propeller's blade number,speed,hub diameter,type of blade section,thickness,and chord length for AUV's model is given.Through CFD simulation,the nominal wake at the location of propeller is abtained.Combined with the propeller design program,the influence of nominal wake on the performance of propeller is got.3.In order to further enhance the performance of the propeller,the relationship between the propeller's parameters and performance is discussed.By optimizing propeller's pamameters like aspect ratio,thickness and pitch,the efficiency and strength of propeller can be improved,and the vibration of AUV will be reduced.Then the performance curve,3D models and cavitation figure are given.4.The static pressure and velocity profiles which are got from simulation provide a reference to the study of cavitation performance.In order to prove the correctness of the design,CFD is used to simulate the propeller and get open water performance,and then the simulate results with the calculation results are compared.Finally,based on the type,parameters,formats and so on,this paper gives some methods to choose a suitable motor for propeller to improve optimum propulsion system efficiency.