CFD-aided prediction of the shape of abrasive slurry jet micro-machined channels in sintered ceramics
CFD-aided prediction of the shape of abrasive slurry jet micro-machined channels in sintered ceramics
复制标题
DOI：
10.1016/j.ceramint.2016.01.091
复制
发表时间：
2016-05
影响因子：
5.2
通讯作者：
K. Kowsari;H. Nouraei;B. Samareh;M. Papini;J. K. Spelt
中科院分区：
文献类型：
--
作者：
K. Kowsari;H. Nouraei;B. Samareh;M. Papini;J. K. Spelt
烧结陶瓷的极高硬度使其难以经济地加工。磨料浆体射流微加工（ASJM）是一种低成本的烧结陶瓷材料微加工方法，它利用含有细磨料颗粒的水的微射流冲击来腐蚀目标，而不会造成工具磨损和热损伤，也不需要使用图案化掩模。现有的轮廓预测模型不能解释在烧结陶瓷ASJM中观察到的流场的变化作为通道深度的增加。磨料颗粒流动的这些变化从根本上改变了通道轮廓，使得通道中心线的比侵蚀速率（每质量侵蚀剂去除的材料质量）随着深度的增加而降低，并且当以90°入射角加工时，轮廓改变形状。计算流体动力学（CFD）建模用于推导通道几何形状和侵蚀流（非线性函数）之间的广义关系，该关系用于现有的数值经验模型中，以预测烧结陶瓷中ASJM微通道的深度、宽度和形状;即氮化铝（AlN）、氧化铝（Al 2 O3）和钛酸锆锡（Zn-Sn-TiO 2）。将1 wt%、10 μ m直径的氧化铝浆体射流的比冲蚀率-颗粒撞击角和比冲蚀率-颗粒撞击速度关系用于首程通道的CFD模型中，以获得浅陶瓷通道内浆体射流的冲蚀模式（冲蚀效率分布）。然后，将这种浅的第一道侵蚀模式推广，并与非线性函数一起用于预测更深渠道的形状。对于90°和45°的喷嘴角度，在向前或向后通道加工配置中，在横截面上任何点处三种陶瓷中的每一种中的预测深度在测量通道的深度/宽度纵横比约为0.5的6%内。
The extreme hardness of sintered ceramics makes it difficult to machine them economically. Abrasive slurry-jet micro-machining (ASJM), in which a target is eroded by the impingement of a micro-jet of water containing fine abrasive particles, is a low-cost alternative for micro-machining of sintered ceramic materials without tool wear and thermal damage, and without the use of patterned masks. Existing profile prediction models could not account for changes in the flow field observed in the ASJM of sintered ceramics as channel depth increased. These changes in the flow of abrasive particles fundamentally altered the channel profiles so that the specific erosion rate (mass of material removed per mass of erodent) of the channel centerline decreased with increasing depth and, when machined at 90° incidence, the profiles changed shape. Computational fluid dynamic (CFD) modeling was used to derive a generalized relation between channel geometry and erosive flow (the nonlinearity function), which was used in an existing numerical-empirical model to predict the depths, widths, and shapes of ASJM micro-channels in sintered ceramics; i.e. aluminum nitride (AlN), alumina (Al2O3), and zirconium tin titanate (Zn–Sn–TiO2). The specific erosion rate-particle impact angle and specific erosion rate-particle impact velocity relations, measured for 1 wt%, 10 μm-diameter alumina slurry jet, were used in a CFD model of a first-pass channel to obtain the erosive pattern (erosive efficacy distribution) of the slurry jet within a shallow ceramic channel. This shallow, first-pass erosion pattern was then generalized and used with the nonlinearity function to predict the shapes of deeper channels. The predicted depths in each of the three ceramics at any point on the cross-section were within 6% of those of measured channels up to a depth/width aspect ratio of about 0.5 for nozzle angles of both 90° and 45° in both the forward or backward channel-machining configurations.