水下射弹典型空化器的超空泡形态特性分析

Analysis of Supercavity Shape for Underwater Projectile With Typical Cavitator

基于均匀多相流假设,建立了水下射弹自然超空泡流动的多相流CFD模型,研究了圆锥和圆盘2种头形空化器的超空泡形态特性,分析了空化数、头形、半锥角、空化器直径等对超空泡形态特性的影响,圆盘空化器有利于水下射弹形成超空泡流.在此基础上,通过FLUENT软件的自定义函数将边界条件的来流速度转化为时间的函数,数值模拟了圆盘空化器水下射弹的空泡流发展过程,分析了射弹在水下运行过程中空泡形态的变化特性.结果表明,射弹在水下航行中,表面形成的超空泡长径比很大,随着空化数的增加,超空泡流迅速衰减.

Based on homogeneous hypothesis, a multi-phase CFD model of natural supercavity flow for underwater projectile was built. Natural supercavity shapes of disk cavitator and coniform cavitator were calculated, and the influences of cavitation number, headforms, half cone angle and cavitator diameter on supercavity shape were analyzed. Disk cavitator makes for supercavitaty flow of underwater projectile. According to the model, user-defined function for the timedependent free stream velocity was implemented into FLUENT software. Supercavity flow around underwater projectile with disk cavitator was investigated by numerical simulation, and the variability of supercavitation was analyzed during underwater sailing. The results show that the ratio of length to diameter of supercavity of underwater projectile is very large, and the supercavity reduces rapidly with the increase of cavitation number.