水下高速航行体自然超空泡形态特性仿真研究

Simulation on Natural Supercavitation Characteristics of Underwater High-speed Vehicle

为使水下高速航行体获得减阻量,基于均匀多相流假设,建立了水下高速航行体自然超空化流动的多相流计算流体力学模型。应用商业软件Fluent 6.2进行了水下高速航行体自然超空泡计算,对比分析了带圆锥和圆盘空化器的两种高速航行体形成超空泡的空泡长度、空泡直径、空泡含汽率和航行体表面的空泡厚度等超空泡形态特性。数值模拟了带圆盘空化器头部航行体的超空泡流发展过程,获得了航行体的超空泡形态变化特性。仿真结果表明:圆盘头形空化器有利于航行体超空泡的形成;超空泡的相对直径与相对长度随空化数增加而减小;在水下高速航行过程中,航行体形成稳定超空泡的长细比非常高,随着航行体速度的衰减,其超空泡迅速出现不稳定状态。

Based on the homogeneous flow hypothesis, a multi-phase computational fluid dynamics model of natural supercavitation flow around underwater high-speed vehicle is developed to achieve drag reduction. The supercavitation flow of a vehicle is simulated numerically using the commercial software Fluent 6.2. The supercavitation characteristics of two vehicle models, namely disk cavitator and conical cavitator, are analyzed comparatively based on the length, diameter, gas volume fraction and thickness of their cavitations. The development process of supercavitation flow for a vehicle with a disk cavitator is shown, and the variation of the natural supercavitation characteristics of the high- speed vehicle is obtained. The results show that the disk cavitator is advantageous for supercavitation formation, and the relative diameter and length of supercavitation decreases with the increase of cav- itation number. The slenderness ratio for stable supercavitation formation of a high-speed underwater vehicle is very high, and the instable state occurs with the decrease of the vehicle speed.