电工技术学报  2024, Vol. 39 Issue (17): 5508-5520    DOI: 10.19595/j.cnki.1000-6753.tces.231132
高电压与放电 |
可用于微型开关研发的液态金属桥拉伸断裂过程仿真研究
朱晓楠1, 杨飞2, 张云轩2, 孙晋茹2, 荣命哲2
1.中国船舶集团有限公司第705研究所 西安 710077;
2.西安交通大学电气工程学院 西安 710049
Simulation Analysis of Stretch Induced Breakup of a Liquid-Metal Bridge for the Development of Micro-Switches
Zhu Xiaonan1, Yang Fei2, Zhang Yunxuan2, Sun Jinru2, Rong Mingzhe2
1. The 705 Research Institute China State Shipbuilding Corporation Limited Xi'an 710077 China;
2. School of Electrical Engineering Xi'an Jiaotong University Xi'an 710049 China
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摘要 构建流体仿真模型可以有效地分析液桥拉伸断裂过程中的流体动力学特性,为基于液态金属桥拉伸断裂过程的电弧开断性能调控提供指导。已有的液桥仿真模型基于动网格或其他网格变形方法,无法仿真液桥的大范围拉伸形变和几何断裂。为此,该文提出了一种不依赖网格形变的液桥拉伸断裂有限元仿真方法。该方法对液体设置极大黏度值,以不可流动液体区域对固体进行近似,同时通过极大黏度值界线的移动配合计算域内液体的流出来等效液桥的拉伸,实现了对液桥拉伸断裂过程的仿真。基于该仿真模型探究了液桥体积、拉伸速度等对液桥拉伸断裂过程的影响,获得了全拉伸速度范围内液桥拉伸断裂特性的转变规律。最终,结合实验结果分析了液桥拉伸断裂特性转变对于电弧燃烧模式的影响,给出了全拉伸速度范围内电弧燃烧模式转变相图,为液桥式开关的电弧开断性能调控提供了依据。该文研究内容对微型继电器、接触器等基于液桥断裂原理的微型开关研发具有指导意义。
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朱晓楠
杨飞
张云轩
孙晋茹
荣命哲
关键词 电弧和电接触液态金属桥机械开关直流开断有限元仿真流体仿真    
Abstract:Traditional mechanical switches use a pair of solid-metal sheets as conductive contacts to achieve switch operations. Existence of conductive spots leads to a series of electrical contact stability problems such as the increase of contact resistance, electrodynamic repulsion force between closed contacts and the generation of switching arcs in current breaking, which seriously affect the service life of mechanical switches, especially microswitches like relays and miniature circuit breakers. Stretching a liquid-metal bridge to breakup could realize rapid arc breaking of low-voltage DC ampere-level currents, thereby eliminating the above electrical contact problems caused by solid conductive spots. Constructing a simulation model can effectively analyze the fluid dynamics of a liquid-metal bridge during the stretch induced breakup, providing guidance for the regulation of the liquid-metal bridge's arc breaking performance. Most existed models for liquid bridge's breakup simulation are based on moving mesh or other mesh deformation methods, which cannot simulate the wide range deformation or geometric rupture of a liquid bridge.
To address the above issue, a finite element simulation method that doesn't rely on grid deformation for liquid bridge's breakup is proposed here. This method approximates solids by setting a maximum viscosity for liquids, and simulates the liquid bridge's stretch process by moving the boundary of the maximum viscosity area cooperating with the liquid mass flowing out of the calculating domain. Fluid variations of the liquid bridge obtained from the model are in good agreement with experimental results, in terms of time scale and geometric shape. The model could be used to accurately track the boundary movement and profile development of a liquid bridge during the whole breakup process. Based on this model, fluid dynamics of a liquid bridge during stretch induced breakup could be accurately predicted.
Based on the model, the effects of liquid metal volume and stretching speed on the breakup characteristics of a liquid bridge are explored. Transition law of a liquid bridge's breakup characteristics within the full stretching speed range is also obtained. Liquid bridges with a larger volume have higher curvature tolerance towards external stretching effect, thus could develop larger rupture distances. Increasing the stretching speed can generally increase the rupture distance and bottom distance of a liquid bridge, which helps to create larger space for the development of single arc and double arc in series, shortening the arcing time and improving the breaking performance in the end. The stretching speed also affects the order of two times ruptures of the liquid bridge through competition with the effect of gravity. As the stretching speed increases, two times ruptures of the liquid bridge follow a transition pattern of firstly rupturing at the lower end, simultaneous rupturing at both ends, and firstly rupturing at the upper end.
Combined with experimental results, the influence of liquid bridge breakup characteristics' transition on the arc regimes was analyzed, and the phase diagram of the arc regimes' transition within the full stretching speed range was given, providing a basis for regulating the arc breaking performance of the liquid bridge-based switch. Within the full stretching speed range, electrical arc regimes' transition routes of the liquid bridge are more diverse. At the critical transition speed, breakup of the liquid bridge will directly give birth to the Regime Ⅱ where two electrical arcs elongate in series. At higher stretching speeds, “Regime Ⅱ Plus” of electrical arcs emerge due to multiple breakups of the liquid bridge. In the above two situations, electrical arc breaking performance of the liquid bridge is superior.
This study has strong reference significance for the study of both fluid simulation methods for liquid bridge breakup and the development of liquid bridge-based microswitches such as relays and contactors.
Key wordsElectric arc and electrical contacts    liquid-metal bridge    mechanical switches    DC interruption    finite element simulation    fluid simulation   
收稿日期: 2023-07-17     
PACS: TM501  
基金资助:国家自然科学基金(52077172)和陕西省三秦创新团队“先进直流电力装备关键技术及其产业化示范创新团队”资助项目
通讯作者: 杨 飞 男,1982年生,教授,博士生导师,研究方向为直流电力开关设备、电力设备数字化设计与智能制造、开关器件新原理及其应用等。E-mail:yfei2007@mail.xjtu.edu.cn   
作者简介: 朱晓楠 男,1995年生,博士,工程师,研究方向为装备电气性能综合测试技术和多物理场仿真分析。E-mail:zxnxjtu@163.com
引用本文:   
朱晓楠, 杨飞, 张云轩, 孙晋茹, 荣命哲. 可用于微型开关研发的液态金属桥拉伸断裂过程仿真研究[J]. 电工技术学报, 2024, 39(17): 5508-5520. Zhu Xiaonan, Yang Fei, Zhang Yunxuan, Sun Jinru, Rong Mingzhe. Simulation Analysis of Stretch Induced Breakup of a Liquid-Metal Bridge for the Development of Micro-Switches. Transactions of China Electrotechnical Society, 2024, 39(17): 5508-5520.
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https://dgjsxb.ces-transaction.com/CN/10.19595/j.cnki.1000-6753.tces.231132          https://dgjsxb.ces-transaction.com/CN/Y2024/V39/I17/5508