| With the exploration of abyssal sea resources and military needs around the world,the requirements for the maneuverability of submarines are also higher.Maneuverability is an important part of the comprehensive performance of submarines,especially since the change of depth is of great significance to the navigation safety of submarines.In the process of pitch-depth motion of the submersible in the vertical plane,the intuitive motion characteristics are of great sense the analysis and calculation of the submersible maneuverability.In this paper,the screw mixed-flow water-jet propulsion submersible is taken as the research.The(SST)k-? turbulence model and dynamic mesh technique are used to study the hydrodynamic characteristics of a submarine in the process of variable vector deflection angle,and the accuracy of the numerical method is verified by comparing the calculation results with the experiment.To study the pitching dynamic characteristics of the submersible,a mathematical model of motion is established by analyzing the underwater force of the submersible.Then,by using the numerical calculation method,the UDF is loaded by the dynamic mesh calculation method of Fluent software to numerically simulate the variable speed and pitch motion state of the submersible,and the hydrodynamic performance characteristics of the submersible in the complex flow field are studied.The main research contents of this paper are as follows:1.Firstly,numerical calculation and experimental verification are used to study the thrust and torque of the waterjet propulsion pump in the whole basin at five different impeller speeds of 1200 rpm,1500 rpm,2000 rpm,2500 rpm and 3000 rpm,respectively.The results show that the thrust,torque and speed of water-jet propulsion obey the quadratic function relationship,and the numerical calculation results are basically consistent with the experimental results.2.Based on the force analysis of the underwater motion of the submersible,the motion of the submersible is combined with the geometric parameters of the spiral mixing pump and the impeller speed,and the dynamic model of the underwater pitching motion of the submersible is established.The relationsh ip between the speed and the speed and thrust is obtained by numerical calculation.3.Through the analysis of the sub-aqua sport process of the submersible,the speed of the submersible corresponding to different impeller speeds is discrete,and the speed is loaded to the hull based on explicit UDF,and the drag and buoyancy of the submersible hull are numerically simulated.The research shows that the various laws of buoyancy and drag of submersibles under different motion states are similar,and the variation is the largest at the initial stage of motion.4.In the process of adjusting the pitch angle of the submersible,the angle between the nozzle of the screw mixed-flow pump and the central axis of the propeller,namely the vector deflection angle,is changed.The variation trend of pitching moment and resistance in the process of changing deflection angle is obtained by numerical calculation.The research shows that with the gradual increase of the vector yaw angle,the resistance of the submersible also increases.At the same time,the resistance of the submersible in the elevation motion state is larger than that in the pitch angle.5.Using a two-phase flow numerical simulation method to study the change of hydrodynamic characteristics of the submersible when the free surface floats to the near-surface.The research shows that the total res istance of the submersible increases first and then decreases gradually with the change o f wave excitation.The distance between the gas-liquid interface and the hull decreases,and the flow accelerates,resulting in the pressure difference on the hull surf ace so that the submarine is subjected to upward suction.By comparing the effects of di fferent elevation angles on the wave height,it can be found that the wave height of the free surface is the largest under the condition of 12° elevation angle. |
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