【题目】波纹管泵中气蚀和剪切的分析瞬态CFD模拟和高速可视化

【作者】Tianyi Ge, Liang Hu, Rui Su & Xiaodong Ruan

【摘要】气动驱动波纹管泵（PDBPs）是半导体工业中一个重要的流体控制部件。然而，在处理特定的化学机械抛光（CMP）泥浆时，可能会发生颗粒团聚，导致晶片表面的划痕、颗粒残留、凹坑和其他缺陷。团聚的主要原因被认为是PDBPs中的空化和过度剪切。建立了高保真多相计算流体动力学（CFD）模型，充分解决了止回阀在水动力和其他外部载荷下的响应，以评估pdbp的空化行为和剪切分布。此外，还建立了一个可视化的空化流模式的测试平台，并验证了CFD模型的准确性。在高速可视化捕获的不同空化区域中，入口阀端环内前缘附近的区域占主导地位，其强度高，持续时间长，形态演化复杂。对优势区空洞的详细起爆过程和发育过程进行了数值分析。估算了pdbp不同区域的剪切速率，入口阀区域比较突出。在端环的前沿附近观察到最强的剪切速率。此外，对空化和剪切之间关系的分析表明，由于强剪切而产生的高强度涡旋是空化开始的原因。本研究有助于理解pdbp的内流细节，并为进一步优化类似泵提供了指导。

【关键词】空化、剪切、波纹管泵、高速可视化、计算流体动力学

[Title] Analysis of cavitation and shear in bellows pump: transient CFD modelling and high-speed visualization

[Authors] Tianyi Ge, Liang Hu, Rui Su and Xiaodong Ruan

[Abstract] Pneumatic drive bellows pumps (PDBPs) are a crucial fluid control component in the semiconductor industry. However, when dealing with specific chemical mechanical polishing (CMP) slurries, agglomeration of particles can occur, leading to scratches, particle residues, pits, and other defects on the wafer surface. The leading cause of agglomeration has been proposed to be cavitation and excessive shear in PDBPs. A high-fidelity multiphase computational fluid dynamics (CFD) model, which fully resolves the response of check valves under hydrodynamic and other external loads, was established to evaluate cavitation behaviour and shear distribution in PDBPs. Moreover, a test rig was built to visualize cavitating flow patterns in PDBPs and verify the accuracy of the CFD model. Among different cavitation regions captured by high-speed visualization, the region near the inner leading edge of the end-ring of the inlet valve is dominant, with high intensity, long duration, and complex morphology evolution. Detailed initiation and development process of cavities in the dominant region are analysed numerically. The shear rate in different domains of PDBPs is estimated, and the inlet valve domain stands out from the other. The strongest shear rate is observed near the leading edge of the end-ring. Furthermore, an analysis of the relationship between cavitation and shear indicates that the high-intensity vortices generated owing to strong shear account for the inception of cavitation. This study contributes to understanding inner flow details in PDBPs and provides a guideline for further optimization of similar pumps.

[Keywords] Cavitation; shear; bellows pump; high-speed visualization; computational fluid dynamics