Numerical modeling and experimental investigation of a two-phase sink vortex and its fluid-solid vibration characteristics

Abstract

A sink vortex is a common physical phenomenon in continuous casting, chemical extraction, water conservancy, and other industrial processes, and often causes damage and loss in production. Therefore, the real-time monitoring of the sink vortex state is important for improving industrial production efficiency. However, its suction-extraction phenomenon and shock vibration characteristics in the course of its formation are complex mechanical dynamic factors for flow field state monitoring. To address this issue, we set up a multi-physics model using the level set method (LSM) for a free sink vortex to study the two-phase interaction mechanism. Then, a fluid–solid coupling dynamic model was deduced to investigate the shock vibration characteristics and reveal the transition mechanism of the critical flow state. The numerical results show that the coupling energy shock induces a pressure oscillation phenomenon, which appears to be a transient enhancement of vibration at the vortex penetration state. The central part of the transient enhancement signal is a high-frequency signal. Based on the dynamic coupling model, an experimental observation platform was established to verify the accuracy of the numerical results. The water-model experiment results were accordant with the numerical results. The above results provide a reference for fluid state recognition and active vortex control for industrial monitoring systems, such as those in aerospace pipe transport, hydropower generation, and microfluidic devices. 目 的 汇流旋涡的实时监测可有效促进冶金精炼、 燃料系统、 水力发电等工业场景的提质增效. 本文旨在建立两相旋涡流固耦合模型, 获取壁面冲击振动信号和提取旋涡贯穿特征, 以期为工业防涡和抑涡提供理论参考与技术支持. 创新点 1. 建立了涡流力学模型, 得到了临界贯入状态的规律; 2. 建立了流固耦合模型, 得到了涡激振动信号; 3. 提出了一种基于四方程的振动响应求解方法. 方 法 1. 采用水平集方法, 建立自由汇流旋涡模型来研究气液两相作用机理; 2. 建立流固耦合动力学模型, 研究冲击振动特性, 并揭示临界流动状态的转变机理; 3. 搭建实验观测平台, 验证数值计算结果的准确性. 结 论 1. 涡流耦合能量引起的压力振荡是流固冲击振动产生的根本原因; 2. 旋涡达到临界穿透状态时, 两相耦合引起的压力振荡导致各频率信号显著增强, 且高频波段尤为明显; 3. 根据流体动力学相似理论搭建的实验平台可基于冲击振动特性实现对汇流旋涡的实时监测.