Influence of ventilation parameters on water entry cavitation of disk cavitation vehicle

通气参数对圆盘空化器航行体入水空泡的影响

¹ School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China
² Military Representative Bureau of the Army Equipment Department in Xi'an, Xi'an 710032, China

Received: 13 October 2023

Abstract

In order to explore the impact of ventilation parameters on the characteristics of water entry cavitation, the VOF multi-phase flow model, the realizable k-ε turbulence model and the Singhal cavitation model are used to establish the high-speed water entry flow field simulation method. The comparison with the experimental results from open literature verifies the feasibility of the simulation method. The influence of ventilation parameters on the ventilation super-foam shape is studied. The results show that the ventilation from behind a cavitation device is conducive to the generation and development of a water entry super-foam and can promote the gas flow in the foam, extending the time for water entry foam closure and increasing its size. When the cavitation is not closed at the beginning of water entry, ventilation or not has little effect on the shape of the foam, whose maximum diameter difference is within 0.015D. In the continuous water entry process, the size of the foam increases with the increasing ventilation, which increases the foam size significantly. When the ventilation rate is 4.74, the length of the foam increases by 0.32D; its diameter increases by 25%. The ventilation from behind the cavitation device can delay water entry foam closure. The greater the amount of ventilation, the longer the time for foam closure. When the ventilation rate is 2.37, the closure time is 3.2 ms; when the ventilation rate is 4.74, the closure time is 4 ms, indicating that when the amount of ventilation doubles, the foam closure delays by 25%.

摘要

为探究通气参数对入水空泡特性的影响, 采用VOF多相流模型、Realizable k-ε湍流模型和Singhal空化模型, 建立了高速入水流场非定常数值仿真方法, 通过与文献公开的试验结果进行对比, 验证了仿真方法的可行性, 研究了通气参数对通气超空泡形态的影响规律。结果表明: 空化器后通气有利于入水超空泡的生成和发展并会改变泡内气体流动特性。通入空气能够促使泡内气体回旋流动, 使得入水空泡闭合时间得以延迟, 入水空泡尺寸增加。在入水初期空泡还未闭合, 是否通入空气对空泡形态的影响不大, 空泡最大直径差值在0.015D以内; 在持续入水过程中, 空泡尺寸随通气量的增加而增大, 通入空气使得空泡尺寸显著增加, 通气率为4.74时, 空泡长度增加了0.32D, 空泡直径增加了25%。在空化器后方通入空气可使得入水空泡闭合延迟, 通气量越大, 空泡闭合所需时间越长。通气率为2.37, 空泡3.2 ms闭合, 通气率为4.74, 空泡4 ms闭合, 可见通气量增加1倍, 空泡闭合时间在原来的基础上可延迟25%。