由於液晶顯示器的普及，因此用於顯示器內的無鹼玻璃基板需求相對增加，玻璃基板製程中的窯爐製程左右熔融玻璃的澄清度，與生產高品質無缺陷的的薄板玻璃有著密不可分的關係。玻璃窯爐為不透明耐火磚所架構，製程溫度處於1400-1600℃之高溫，進行現場性質量測及內部行為的觀察則耗時且危險性高。若藉由全尺寸或縮小尺寸之物理模型實驗或數學模型計算方式，來探討玻璃窯爐內部流動及熱傳行為，則相對容易觀察、省時、低成本與危險性低。玻璃窯爐的最終目的是要得到高品質的熔融玻璃，而熔融玻璃的品質主要依賴窯爐內熔融玻璃區的熔解、澄清與均質化的能力，也就是與熔融玻璃區內流體的流動與熱傳現象有著密不可分的關係。本研究利用縮小尺寸之物理模型及以SOLA-VOF為基礎的數值模型，來觀測並探討窯爐內之流體流動與熱傳現象，分析窯爐內的設計和各種操作條件的對玻璃品質的影響，進而找出較合適的設計及操作條件，期望提供窯爐設計者及操作者重要的參考資訊。在物理模型方面，利用輻射加熱、電極加熱與底吹攪拌等效應來探討其對窯爐內流體流動的影響，以最小滯留時間與平均滯留時間來作為玻璃品質的評估指標，評估各個效應對玻璃品質的影響，並數值模型的結果來輔助說明物理模型中所觀測到的現象。

在輻射加熱、電極加熱與底吹氣體攪拌效應方面，僅開啟輻射加熱的條件下，模型前段會有類似熱點的現象產生此熱點現象會在模型前段造成環流，使追蹤粒子在前段滯留時間增加並減少粒子越過熱點直接流向出口，此流動型態能夠幫助確保固體玻璃原料在穩定的區域內熔化，避免尚未熔化的原料越過熱點直接流向出口，但後半段窯爐設計對於澄清與均質化的過程則比較不利。僅開啟電極加熱的條件下，本研究中的電極排列設計可造成雙熱點的現象而在第一排電極前與第三排電極後產生雙環流的現象。環流能加速入口處固態玻璃原料熔解效率與滯留時間，並有助於熔融玻璃的澄清與均質化。而第二排與第四排電極能增加玻璃流動路徑與停留時間，並使熔融玻璃內部的氣泡更容易由液面逸出。僅開啟底吹氣體攪拌的操作條件下，在第三排與第四排電極間會造成大範圍的區域環流，滯留時間與攪拌範圍隨著底吹流量增加而增加。本研究底吹氣體設計不僅能增加熱點回流玻璃液的數量，有利於熔化並且降低能耗，並且不會有一般底吹後移所造成澄清效果下降的情形。

在輻射加熱、電極加熱與底吹氣體攪拌效應對滯留時間的影響方面，僅開啟單一操作效應的情況下，開啟底吹氣體攪拌的效應會比開上方輻射或電極加熱的效應大很多，而上方輻射加熱效應又比電極加熱的效應高一些。耦合兩操作效應的情況下，耦合兩操作效應會比單一操作效應大。同時開啟底吹攪拌與輻射加熱的效應，比同時開啟底吹攪拌與電極加熱時的效應高，並且兩者又比同時開啟電極與輻射加熱效應高。在同時開啟底吹氣體攪拌、輻射加熱與電極加熱的情況下，在本研究所使用之1/10物理模型中，最好的操作條件為底吹流量0.667 cm3/sec、電極加熱溫度50℃與輻射加熱溫度100℃。

The production of glass is a very complicated process which involves a number of physical and chemical phenomena. The quality requirement of glass substrate for liquid crystal display (LCD) is much higher and the design requirements of a glass furnace are of a critical and complex nature. The cleanliness of alkali-free glass is one of the most critical qualities of the LCD glass. Due to high temperature operation, it is extremely difficult to observe the glass flow patterns and temperature fields inside the glass-melting furnace. The number of defects in glasses is considered to directly depend on flow and heat transfer behaviors in the molten glass zone. The full-scale experiments in an actual furnace are then very costly and dangerous because of the severe environment. The physical modeling and mathematical modeling methods allow for a clear picture of mass exchange in the glass-melting furnace and enables for recommendations to be made on furnace operation.

In this study, the effects of process conditions such as air bubbling, top radiation heating and electrode heating in a melting furnace on the cleanliness of alkali-free glass, which is characterized by the residence time and trajectories of tracer particles, is investigated by reduced physical models and mathematical model based on the SOLA-VOF technique. For the effects of top radiation heating, hot spot was observed in the front part of physical model. The effects of radiation heating can enhance the effects of glass melting. For the effects of electrode heating, two small zones of circulation were observed in the vicinity of the electrodes. The first one was in the region between the inlet and the first row of electrodes, and the other one was in the region between the third row of electrodes and the bubblers. The circulations can increase the melting efficiency, residence time and the effects of fining and homogenization. For the effects of gas bubbling, the stirring range, the particle trajectory and residence time increased with gas flow rate. This promotes the effects of refining and homogenization in the glass melting tank and finally enhances the quality of the glass melt.

The results showed that the effect of bubbling on residence time is larger than that of top radiation heating which is then larger than that of electrode heating when one single process variable is considered. For the effect of the coupling of two process variables, the dual effect of bubbling and radiation is better than that of bubbling and electrode which is in turn better than that of radiation and electrode. As all three devices were all turned on, it was found that the most desirable condition to obtain clean glass is bubbling with electrode temperature of 50℃ and radiation temperature of 100℃.

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