- 作者: 崔燕勇; 陳建宏
- 作者服務機構: 國立交通大學機械工程學系
- 中文摘要: 本研究係以數值方法探討大尺寸垂直式化學氣相沉積反應器內的流場。描述流場傳輸現象的統御方程式被建構在軸對稱非正交曲線座標上,利用有限體積法將方程式離散化,計算網格係安排成非交錯形式,為避免非交錯網格所造成之速度與壓力相互不耦合的現象,網格面上的速度計算要加以特別處理。結果顯示當晶座加熱到夠高的溫度,流場受到浮力的影響在晶座上方產生迴流,此造成晶座上熱傳遞量的減弱及不均勻的熱通量。藉由旋轉晶座可以抑制迴流的產生,但是卻又會在晶座外緣產生和浮力驅動迴流方向相反的另一種型式迴流。因為浮力和離心力的大小正比於爐內壓力的平方值,所以降低反應器的操作壓力是消除這兩種迴流的有效方法。另外結果也顯示在某一特定的晶座溫度和轉速範圍內,可能存在多重解,此顯示CVD反應器內的流場可能和操作的起始程序有關。
- 英文摘要: This study is concerned with a numerical method to study the flow in large-size vertical chemicalvapor deposition (CVD) reactors. The governing equations that describe the transport phenomena in thereactors are constructed in axisymmetric, curvilinear coordinates to fit an irregular geometry. Discretizationis carried out using a finite-volume method. Since grids are arranged in a nonstaggered manner, specialtreatments are undertaken for calculation of face velocities such that decoupling between the velocity andpressure is avoided. The calculation shows that the buoyancy force resulting from the heated susceptormay cause recirculating flow above the susceptor when the temperature is high enough, leading to reductionof heat transfer and nonuniform distribution of heat flux. The recirculation can be suppressed by rotatingthe susceptor. However, a different kind of recirculation, rotating in the direction opposite to the buoyancy-driven recirculation, may be formed at the outer edge of the susceptor. An effective way to remove theserecirculating flows is to reduce the reactor pressure because the buoyancy force and centrifugal force areproportional to the square of the reactor pressure. It is also shown that multiple-flow solutions may existin certain temperature and rotational speed ranges Thus, the flow in the reactor may depend on the start-up procedure.
- 中文關鍵字: vertical CVD reactor flow; numerical simulation; chemical vapor deposition
- 英文關鍵字: --