近場光碟片與稀薄流場中空氣軸承之研究

Abstract

對於模擬具有單相和複合相的流體或包含複雜的物理性質的問題而言，晶格波茲曼法是一套效率很高而且又能平行化運算的方法，且晶格波茲曼法特別適用於處理複雜的邊界情形和多相的介面。近來晶格波茲曼法更擴展至能處理紊流及具有擴散效應的系統上。 旋轉中碟片發生振動變形甚至波動傳播。其運動方程式以偏微分方程式表示，本研究利用FEMLAB軟體求解，它是一套針對於能以偏微分方程式描述工程問題，以有限元素法進行分析和模擬的電腦輔助工程分析軟體。 因近場光學必須在極接近反射面約50奈米處做讀取的動作，故採用飛行讀寫頭的架構，由於之間的間隙非常的小，使得碟片上方飛行讀寫頭飛行的高度會被其中的稀薄氣體流場影響。因此本研究利用晶格波茲曼法分析介於飛行讀寫頭和碟片間的空氣軸承的壓力分佈，並且利用FEMLAB軟體計算承受點施力作用下碟片的變形，結果與文獻比較作驗證。

The lattice Boltzmann method (LBM) is an efficient algorithm for simulating single-phase and multiphase fluid flows and for combining physical complexities. The LBM is especially useful for modeling complicated boundary conditions and multiphase interfaces. Disk rotation causes disk deformation and even wave propagation. The disk equation of motion is expressed by partial differential equations. This study employs a FEMLAB software, based on the finite element method, to solves partial differential equations. A near-field optical disk drive uses near-field optics to read/write disk data with a flying height at about 50nm. However, the flying height is affected by pickup head vibration, disk vibration, and airflow between the flying head and disk. This study adopts LBM to compute pressure distribution for the air bearing between the pickup head and disk. Moreover, this study employs FEMLAB to solve disk equations of motion and obtain disk deformation subject to a point force that accounts for the air bearing force. Computational results are compared with the literature to validate the model.