本文研究的目的在於利用數值方法模擬潔淨室內潔淨氣流流經工作機台時，造成流場與磁場的改變進行研究與分析。數值方法是以三階上風的有限體積法與二階中央差分法來求解二維磁流力學方程式（Magnetohydynamic Equations, MHD），並在連續方程式中加入人工壓縮因子法。其中在對流項（convection）中採用高階的上風有限體積法（high-order upwind finite volume techniques ），在黏滯項（viscous）中則採用二階有限體積法。在磁場方面，由於磁場的散度守恆性，採用二階的中央差分法來計算磁場的分佈。
在物理模型方面，當潔淨氣流流經工作機台時，會形成迴流區域，本文並以簡單的模型作測試。同時發現磁場參數的增加將抑止渦流的產生，降低作用在鈍形體（bluff body）上流體的各種力。

關鍵字：有限體積法、人工壓縮因子、磁流力學、散度守恆性

A numerical method is developed to simulate the change of the flow field and magnetic field when clear air passes through a working platform. The numerical method is used a third-order upwind finite-volume scheme and second-order central finite difference scheme to solve the two-dimensional Magnetohydynamic Equations. The artificial compressibility method is applied in the continuity equation. It uses a high order finite-volume scheme for the convective terms and a second-order finite-volume scheme for the viscous terms. In the magnetic field, because of divergence free condition of magnetic field, the second-order central finite difference scheme is applied.
When clear air passes through a working platform will generate non-uniform circulation zones. We found the magnetic parameter increasing can suppress vortex and to reduce the fluid force acting on a bluff body.

Keyword：Finite-Volume method, Artificial Compressibility,
Magnetohydrodynamics（MHD）,Divergence Free Condition

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