Hydrodynamic Numerical Study Of New Energy-saving Appendage Behind Propeller

With the increasing scale of the world economy,the world’s energy consumption continues to grow,energy is increasingly tense,and the ship is a highly energy dependent means of transport,so the research on ship energy saving technology is of great significance.The application of ship energy saving appendages has become one of the main measures of ship energy saving.Energy saving appendages of ship have the advantages of simple structure,easy installation and so on,and play an irreplaceable role in improving the flow field around the ship and improving the propulsion efficiency,especially in the high energy consumption bulk carriers.In order to recover this part of energy loss and improve the propulsion efficiency of the propeller,a new type of energy-saving appendage of the vane wheel is proposed in this thesis.The open water performance prediction and energy-saving effect analysis of the new type of the hub vortex absorbed booster vane wheel behind are carried out,and the optimal structural parameters of the new type of energy-saving appendage are determined.Taking the optimized new type of the hub vortex absorbed booster vane wheel behind the propeller as the numerical simulation model,The energy-saving effect of self-propelled numerical calculation of ship and propeller with energy-saving appendage is further analyzed.The main research contents are as follows:(1)Numerical study on open water performance of energy saving appendage of a new type of the hub vortex absorbed booster vane wheel behind the propeller.Based on the sliding grid method,the open water performance of KP505 propeller is simulated by CFD software STAR-CCM+.The results are compared with the experimental data to verify the reliability of the calculation method.The open water numerical simulation method is used to predict the open water performance of the combined system of propeller and the hub vortex absorbed booster vane wheel.The thrust coefficient,torque coefficient and open water efficiency of the combined system are analyzed under different coefficients.The numerical results are compared with the test results of the propeller’s individual open water performance,and the energy saving effect of the hub vortex absorbed booster vane wheel is analyzed.According to the changes of the streamline,axial velocity,circumferential velocity vector and the surface pressure of the model before and after installation,the working principle of the new type of the hub vortex absorbed booster vane wheel is analyzed.(2)Numerical study on variable parameter open water performance of energy-saving appendage of a new type of the hub vortex absorbed booster vane wheel behind the propeller.The parametric numerical simulation of the open water performance of the combined system of propeller and the hub vortex absorbed booster vane wheel is completed by changing the structural parameters.The single parameters of the hub vortex absorbed booster vane wheel(the number of blades,the installation distance between the blades and the front propeller,the diameter and the number of the rectifying blades)are changed.The thrust coefficient,torque coefficient and open water efficiency of the combined system under different advance speed coefficient are calculated.The influence of the change of the structure parameters on the open water performance is analyzed.According to the comparison of open water efficiency,and a new type of energy-saving appendage of the hub vortex absorbed booster vane wheel with better energy saving effect is designed.(3)Numerical study on self propulsion hydrodynamic performance of coupling model of KCS ship,propeller and energy saving appendage of the hub vortex absorbed booster vane wheel.The sliding grid method is used to simulate the self-propelled performance of coupling model of KCS ship and KP505 propeller,and the calculation results and experimental values are compared and analyzed to verify the reliability of the self-propelled numerical simulation method.On the basis of the coupling model of ship and propeller,the new type of the hub vortex absorbed booster vane wheel was added.The self-propelled numerical simulation is carried out again.The energy-saving efficiency of the hub vortex absorbed booster vane wheel was evaluated by comparing numerical results before and after the installation,and the new type energy saving appendage of the hub vortex absorbed booster vane wheel was further revealed the influence on the hydrodynamic performance of the propeller.