Research on numerical calculation of vehicle water exit under different sailing conditions
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摘要: 航行器出水过程极其复杂, 伴随着多相流、空化、相变、湍流不稳定性, 其所受作用力呈现强的非定常、非线性。国内外对于航行器带空泡出水问题的研究, 多为航行器垂直或者倾斜出水, 关注点往往在于航行器运动轨迹及姿态, 超空泡航行器出水过程研究较少, 本文基于STAR-CCM+软件, 采用重叠网格技术进行网格划分, 使用VOF模型捕捉气液交界面, Schnerr-Sauer模型描述航行器周围的空化过程, 建立了航行器出水过程的数值计算模型。对航行器在不同航行条件(初始速度、初始水深、通气量)下的出水过程进行仿真计算, 得到了不同工况下的流场和空泡演化规律, 分析了超空泡航行器的流体动力特性与运动特性。仿真结果表明, 不同初始运动速度的航行器其水下运动呈现出2种不同的模式。不同水深下, 初始空化数不同, 在较深的水域航行器周围空泡更容易破裂; 加大通气量可以有效地改善空泡形态。Abstract: Vehicle exiting-water process is very complicated, accompanied by multiphase flow, cavitation, phase transition and turbulence instability, and the applied force is highly unsteady and nonlinear. Mostly, studies of vehicle exiting-water with cavitation focus on the vertical or oblique exiting-water internationally, and is focus on the trajectory and attitude of the vehicle.There are few studies on the exiting-water process of the supercavitation vehicle. In this paper, based on STAR-CCM+ software, overlapping grid technology is used to for meshing, VOF model is used to capture the gas-liquid interface, Schnerr-Sauer model describes the cavitation process around the vehicle, and a numerical calculation model of the exiting-water process is established. The flow field and cavitation evolution laws under different conditions that includes initial velocity, initial water depth and ventilate mass flow are obtained, and the hydrodynamic and kinematic characteristics of the supercavitating vehicle are analyzed. The simulation results show that the underwater motion of the vehicle with different initial motion velocity presents two different modes. Under different water depths, the initial cavitation number is different. Cavitation around the vehicle is more likely to rupture in deeper waters. The cavitation morphology can be improved effectively by increasing the ventilation flow rate.
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Key words:
- vehicles /
- water exit /
- overlapping grid /
- cavity form
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表 1 经验公式结果与仿真结果对比
Table 1. Comparison table between empirical formula results and simulation results
经验公式 仿真结果 误差(%) 最大空泡半径(m) 0.086 735 0.083 226 4.01 最大空泡长度(m) 2.17 2.27 773 4.73 表 2 不同初始速度工况表
Table 2. Table of different initial velocities conditions
工况标记 初始速度v(m/s) 通气量qM(kg/s) 空化器角度(°) 初始深度h(m) #1 90 0.1 10 3 #2 100 #3 110 #4 120 表 3 不同水深计算工况表
Table 3. Table of different water depth calculation working conditions
工况标记 初始水深h(m) 通气量qM(kg/s) 初始速度v(m/s) 空化器倾角(°) #1 3 0.1 100 10 #2 4 #3 5 #4 6 表 4 不同通气量计算工况表
Table 4. Table of different ventilation flow calculation working conditions
工况标记 通气量qM(kg/s) 初始速度v(m/s) 空化器角度(°) 初始深度h(m) #1 0.09 100 10 3 #2 0.10 #3 0.11 #4 0.12 -
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