Boiling induced macroscopic erosion of plasma facing components in fusion devices
Boiling induced macroscopic erosion of plasma facing components in fusion devices
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DOI：
10.1016/j.fusengdes.2010.10.002
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发表时间：
2011-03
影响因子：
1.7
通讯作者：
Y. Shi;G. Miloshevsky;A. Hassanein
中科院分区：
文献类型：
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作者：
Y. Shi;G. Miloshevsky;A. Hassanein
在托卡马克装置的等离子体不稳定过程中，面向等离子体的金属元件(PFC)会发生表面熔化和汽化。在这些不稳定性过程中形成的熔体层的宏观损失严重影响到PFC的寿命、附近组件的损坏以及潜在的堆芯等离子体污染。由于杂质和溶解气体的存在，沸腾发生在过热的熔体层中。不断增长的气泡在熔体层表面破裂，并诱导喷射液滴的喷射，因此对PFC的冲蚀起到了重要作用。本文采用一维移动边界模型研究了沸腾机理，该模型考虑了加热、熔融、汽化和再凝固过程。用计算流体力学数值模拟方法研究了单个气泡空穴的坍塌和射流的形成，结果表明，对于液态钨和铝，喷射液滴的数量约为初始气泡体积的∼1%。沸腾强度随熔体压力的增大而减小，随入射热流密度的增大而增大。模拟和实验表明，钨和铝的沸腾特性得到了类似的结果。本文给出的沸腾烧蚀的简单而真实的模型，可以更好地理解威胁金属PFC寿命的机制。
During plasma instabilities in tokamak devices, metallic plasma facing components (PFC) can undergo surface melting and vaporization. Macroscopic losses of melt layers developed during these instabilities are of a serious concern to the lifetime of PFC, the damage of nearby components, and potential core plasma contamination. Due to the presence of impurities and dissolved gas, boiling occurs in the superheated melt layer. The growing bubbles burst at the melt layer surface and induce the ejection of jet-droplets, therefore, contributing significantly to the erosion of PFC. In the present work, the boiling mechanism is investigated using a one-dimensional moving boundary model accounting for heating, melting, vaporization, and re-solidification. The collapse of a single bubble cavity and the jet formation, investigated numerically using computational fluid dynamics simulations, shows the amount of ejected jet-droplet is about ∼1% of the initial bubble volume for liquid tungsten and aluminum. The intensity of boiling decreases with the pressure in the melt layer and increases with the incident heat flux. Simulations and experiments show similar results on the boiling characteristics of tungsten and aluminum. The simple and realistic model of the boiling induced erosion, presented here, allows better understanding of the mechanisms threatening the lifetime of the metallic PFC.