An Experimental Study on the Flow Behavior near the Read-And-Write Arm in a Hard Disk Drive Model with a Shroud Opening
An Experimental Study on the Flow Behavior near the Read-And-Write Arm in a Hard Disk Drive Model with a Shroud Opening
复制标题
带护罩开口的硬盘驱动器模型中读写臂附近流动行为的实验研究
DOI：
10.1007/s00542-013-1847-3
复制
发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Shinnosuke Obi
中科院分区：
文献类型：
--
作者：
Katsuaki Shirai;Lars Büttner;Jürgen Czarske;Shinnosuke Obi
为了阐明流激振动的机理，采用简化的3.5″模型对硬盘驱动器内部的复杂流动进行了研究。与作者过去的相关研究相比，我们的模型具有非轴对称的几何形状，配备了护罩开口和读/写臂（RWA）。该模型的目的是作为一个基准来研究HDD流在实验和数值模拟。研究了将RWA插入盘间空间后，盘间空间内复杂的流动行为。流量测量进行了一个由透明盘，RWA和覆盖物组成的试验台。测量是在磁盘雷诺数Red = 1.2 × 105下进行的，这对应于真实的3.5“HDD的7，700 rpm的转速。进行了两组流量测量--第一组雷诺应力分量沿沿着四条不同的线测量，RWA以浅角度插入（实验I），另一组平均和均方根速度统计沿沿着几条选定的线测量，RWA以两个不同的插入角度插入（实验II）。沿沿着8条垂直于圆盘表面的不同直线，以30 μm的空间分辨率获得平均速度和速度方差。使用激光多普勒速度轮廓传感器实现了结果的高空间分辨率，其物理分辨率为微米，速度不确定度为0.2%。在实验I中，平均速度和速度方差统计数据与使用轴对称模型的其他研究中的常见结果基本一致，但围带开口处径向的流动行为除外。二次流行为可能是由过去大多数模型中不包括的围带开口引起的。在实验II中，平均速度和速度方差成功地测量通过检查以上和以下的RWA在旋转盘之间的空间中的流动。由此产生的速度统计数据显示，在磁盘和RWA之间的狭窄的1 mm的空间中的湍流Couette样的流动。
Complex flow inside a hard disk drive (HDD) was investigated using a simplified 3.5″ model for clarifying the mechanism causing flow-induced vibration. In contrast to the authors’ related study in the past, our model had a non-axisymmetric geometry equipped with a shroud opening and a read/write arm (RWA). The model is designed to serve as a benchmark to study HDD flows both in experiments and in numerical simulations. The complex flow behavior in the disk-to-disk space was investigated with the RWA inserted into the inter-disk space. Flow measurements were carried out with a test rig which consisted of transparent disks, RWA and covers. The measurements were performed at the disk Reynolds numberRed= 1.2 × 105which corresponds to the rotation speed of 7,700 rpm of a real 3.5″ HDD. Two sets of the flow measurements were performed—the first Reynolds stress components measured along four different lines with the RWA inserted at a shallow angle (experiment I), and the other mean and rms velocity statistics along several selected lines with two different RWA insertion angles (experiment II). The mean velocity and velocity variance were obtained at a spatial resolution of 30 μm along eight different lines perpendicular to the disk surfaces. The high spatial resolution of the results was achieved using a laser Doppler velocity profile sensor with a physical resolution in micrometers and a velocity uncertainty of 0.2 %. In the experiment I, the mean velocity and velocity variance statistics were mostly consistent with the common findings in other studies using axisymmetric models except for the flow behavior in the radial direction at the shroud opening. The secondary flow behavior was likely caused by the shroud opening which was not included in most of the models in the past. In experiment II, the mean velocity and velocity variance were successfully measured through examination of the flow above and below the RWA in the space between the rotating disks. The resulting velocity statistics exhibit turbulent Couette-like flow in the narrow 1 mm space between the disks and the RWA.