Study On Propeller Characteristics Of Air Drag Reduction Ship And Interference Between Hull And Propeller

With the development of the world economy and shipping industry,high~speed boats are increasingly concerned by all the people.While the global warming and environmental pollution is serious,the significance energy conservation significance is particular important.Reduction of the resistance of sliding boat through the gas layer can reduce energy consumption while reducing the environmental pollution of the sailing water.As the speed of the jets increased,the resistance increased dramatically,and the cost of further improvement in the speed of the jets was a significant amount of energy consumption.Therefore,it is a feasible way to improve the comprehensive navigation performance of the sliding boat by reducing its resistance.It has obtained the general attention and consensus.At the same time,the pressure on the rear propeller surface of the high speed craft will gradually increase,and the rotation of the propeller itself will produce a lot of vacuoles,so that the efficiency of the propeller is reduced.It is not clear how the propeller and gas layer of the air drag reduction ship affect the hydrodynamic performance of the propeller.Therefore,it is necessary to study the mutual interference between the air drag reduction ship and its propeller.Based on the theory of viscous fluid mechanics,this paper discusses the hydrodynamic performance and the theoretical prediction method of multi ~ physical field mutual interference between airflow,sliding boat and its propeller.The turbulence model and the meshing method suitable for high speed rotating propeller performance prediction are discussed,and the theoretical forecasting method with good numerical prediction results is given.The influence of different gas groove shape on the drag reduction of the sliding boat is studied,and the gas groove shape is studied.The ship type research and optimizationgives a better drag reduction performance of the sliding boat type.The VOF model and Euler multiphase flow model were used to study the influence on the frictional resistance and total resistance of the sliding boat with the various ventilation and speed.The resistance characteristics of the air drag reduction ship were analyzed.Based on the theoretical prediction method,the propeller shape,the number and the layout of the propeller are studied.The numerical simulation of the open water performance of the three blades cavitating propeller is carried out and the hydrodynamic performance is analyzed.The total resistance,the shear resistance and the differential pressure resistance are calculated by CFD software(finite volume method),and the minimum total resistance and practical ship type are determined by adding different constraints.The calculation of the propeller and the bair drag reduction ship is carried out.The number,position and size of the propeller are determined by preliminary calculation and analysis of the distribution of the gas flow in the bottom of the ship.The study of the interdigital interference was carried out for the air drag reductionsliding boat with propeller.The results show that the shear resistance and total resistance of the sliding boat are gradually reduced and stabilized with the increase of ventilation.The effect of drag reduction after ventilation is obvious.The difference between the propeller numerical simulation and the experimental value is small,which proves the effectiveness of the theoreticalmethodforecasted.After the gas is introduced,the values of total resistance of the paddle are larger than that of the bare hull.The study of the influence of gas layer on the performance of the propeller of the sliding boat shows that,in general,the bottom ventilation of the hull causes the propeller thrust and torque to decrease,but there is ventilation caused the propeller thrust and the torque increase,which is instructive to the propeller design of the air drag reduction ship.