本研究探討渦流產生器應用於3吋垂直式的半導體廢氣排放管路，藉由CFD軟體Fluent執行流場模擬，將計算結果製作圖表以便觀察其流場缺失；並依動態光散射儀(Dynamic Light Scattering)檢測結果，將廢棄粒子之直徑訂為100nm，由穩態離散相模組之模擬數據清楚呈現其排放效率。首先針對配置氣體噴注器(Gas Injector)之管路設計作模擬，發現氣體噴注器之注入氣流於彎管處往管壁外側流動，且於管壁內側產生局部逆流現象，同時對主氣流形成阻礙而有亂流產生，導致在上游流場出現迴流現象；也觀察到廢棄粒子沉積於彎管和管壁處，其廢棄粒子排放率僅為26%，推測原因乃彎管之迴流現象以及近管壁之黏滯性和低速氣流分佈所致。為解決此問題，本文選定管路進行加熱與增加注入氮氣量兩種規劃，計算結果顯示加熱管路僅改善排放率約3%，而增加流量可強化排放率達13%；可見加熱管路並未能改善粒子沉積之問題，而增加注入量之效果很好，但改良方案之粒子排放率僅為41%。
接著本研究將渦流產生器(Vortex Generator)應用在此廢氣管路系統，渦流產生器具有多個注入孔可使氣流均勻分布於管壁，令注入高壓氣體沿著管壁形成渦流往下游移動，而得以去除粒子沉積於管壁之現象，同時因氣流沿管壁注入，可有效避免掉氣體噴注器所產生之迴流現象。為優化渦流產生器之設計，本研究在總注入流量固定下，選定注入斜孔之直徑與數量作系統化的參數分析；相對應之數值模擬結果顯示，斜孔總面積變化會使注入流速隨之改變，若斜孔出口流速越慢，則對上游之阻礙變小而使迴流現象減少，自然對廢棄粒子之排放率越高，因此推測注入氣體流速即為影響排放效率之主要因素。綜合歸納計算結果得知渦流產生器確實能有效改善沉積現象而順利排出粒子，其中本研究中排放率最高的16個斜孔直徑1.8mm的渦流產生器，規劃配置於排放廢氣管路為最優化設計方案，其排放率高達84.5%。

This study investigates the application of vortex generator on a 3-inch vertical pipeline for discharging the waste products of the semiconductor fabrication process. At first, the CFD software Fluent is used to simulate the flow field and identify the adverse flow pattern associated with the common-used pipeline equipped with three gas injectors and a high-temperature exhaust-gas treatment unit. Also, with the aids of the discrete phase module (DPM) under steady and non-interactive condition, efficiency of waste particle emission is calculated by releasing waste particles with 100nm-in-diameter, which is determined based on the size distribution report of dynamic light scattering test. The numerical results show that the non-uniform velocity distribution and the backflow near inner side are observed around three elbow regions. In addition, an obvious recirculation appears in the upstream of gas injector since the injecting gas forms an obstacle for the main flow. It follows that many waste particles are accumulated in the circulation and near the pipe wall. And, the discharge efficiency of waste particles is calculated as 26%. To solve this problem, heating the pipe wall and increasing the injection Nitrogen flow rate are proposed and evaluated numerically. The outcomes reveal that a significant 13% and a minor 3% enhancements are found for a larger flow rate and a heating pipe, respectively. Thus, the best discharge efficiency is 41% for the pipe systems with traditional gas injectors.
Thereafter, a vortex generator is proposed and installed at the inlet end of this exhausting-gas pipeline to generate a series of apparent vortices moving along the wall for effectively eliminating the phenomenon of particles depositing on the pipe wall. These vortices are formed by the high-temperature, high-pressure air streams via the injection holes distributed evenly over the outer circle of vortex generator. Clearly, the injecting gas is divided equally into several small circulating air flows, which can diminish the undesirable resistance to the main stream. Moreover, parametric study on diameter and number of injector holes are executed for enhancing the discharge efficiency of pipeline under a fixed injection flow rate. As a result, the corresponding CFD simulations indicate that the injecting flow velocity via the hole is the dominant factor effecting the discharge efficiency of waste particles. Furthermore, 16 slant injection holes with a 1.8mm diameter is the optimal design combination for vortex generator. The exhaust-gas pipeline with this optimum vortex generator yields an excellent particle-emission efficiency at 84.5%.

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