臺灣大學: 應用力學研究所陳發林林宜庭Lin, Yi-TingYi-TingLin2013-03-212018-06-292013-03-212018-06-292012http://ntur.lib.ntu.edu.tw//handle/246246/249752在研究平面流鑄製造非晶質薄帶中，以分析流體動力相關之操作參數為主，缺少對於熱傳效應方面的研究，但在薄帶固化過程中熱傳效應極為重要，所以本研究操控熱傳的操作參數(輥輪熱傳係數、進料溫度) ，利用熱流分析軟體Ansys-Fluent探討其對非晶質薄帶固化過程的影響。本研究設定鑄造材料為 ，設定進料壓力為41125Pa與輥輪速度為20m/s時，分析輥輪熱傳係數的範圍為120 至1 和進料溫度的範圍為1501K至1684K。 分析改變輥輪熱傳係數之模擬結果，發現影響薄帶厚度的因素可能為熔潭長度與冷卻速率，當輥輪熱傳係數在120至400 ，薄帶厚度會由39.8μm降低至36.3μm；當輥輪熱傳係數在400至1000 ，薄帶厚度會由36.3μ升高至37.2μm。在輥輪熱傳係數低於400 ，此時冷卻速率的差異不大，固化線會沿著熔潭長度延伸，熔潭長度越長，固化線越高，所以薄帶厚度會隨著輥輪熱傳上升而下降。當輥輪熱傳係數較高時，因為冷卻速率上升，熔潭長度影響不大，所以薄帶厚度會逐漸上升。 分析改變進料溫度之模擬結果，發現影響薄帶厚度的因素可能為液體黏度與冷卻速率，當進料溫度在15001~1548K，薄帶厚度由36.3μm升高至36.6μm；當進料溫度在1548~1683K，薄帶厚度由36.6μm降低至36.2μm。此外，也發現進料溫度較高時會造成下游熔潭區有較多的渦流產生，進而使薄帶厚度變化率較大。 經由此研究可歸納出當輥輪熱傳係數在400 以上，進料溫度介於1500K至1548K，熔潭流場與薄帶厚度皆有較穩定之情形，可供給未來平面流鑄相關實驗做參考。In the previous studies, the manufactured of amorphous ribbons by planar flow casting, which is mainly analyzed by operating parameters based on fluid dynamics but is seldom studied in the effect of heat transfer. However, the effect of heat transfer is extremely important in the process of ribbon solidification, thus this study focuses on the operating parameters of heat transfer (wheel heat transfer coefficient, molten jet temperature) and researches the effect of amorphous ribbon solidification with different operating parameter by Ansys-Fluent. The casing material is , molten jet pressure is 41125 Pa and the speed of wheel is 20 m/s in this study. The wheel heat transfer coefficient is set from 120 to 1 and molten jet temperature is set from 1501 K to 1684 K. From the simulated results of different wheel heat transfer coefficient, it is found that puddle length and cooling rate may affect thickness of ribbon. When the wheel heat transfer coefficient is set from 120 to 400 , the thickness of ribbon decreases from 39.8μm to 36.3μm; however, when the wheel heat transfer coefficient is set from 400 to 1000 , the thickness of ribbon increase from 36.3μm to 37.2μm. The cooling rate is no apparently different when wheel heat transfer coefficient lower than 400 , at this time the thickness of ribbon becomes thinner while the puddle length get shorter. When wheel heat transfer coefficient higher than 400 , puddle length has no significant influence on the thickness of ribbon, which gets thicker as cooling rate rises. From the simulated results of different molten jet temperature, it is found that viscosity of fluid and cooling rate may affect thickness of ribbon. When molten jet temperature is set from 1501K to 1548K, the thickness of ribbon rises from 36.3μm to 36.6μm. The thickness of ribbon decreases from 36.3μm to 36.2μm when molten jet temperature is set from 1548K to 1683K. In addition, it is found that molten jet temperature causes more eddy currents in downstream of puddle, which leads the changing rate of thickness of ribbon increase. From this study it can be summed up that the velocity field of puddle and the thickness of ribbon become stable when wheel heat transfer coefficient higher than 400 and molten jet temperature between 1500K and 1548K. This study could provide associated studies of planar flow casting as reference.2704670 bytesapplication/pdfen-US非晶質平面鑄造輥輪熱傳係數進料溫度Fe78B13Si9amorphousplanar flow castingwheel heat transfer coefficientmolten jet temperaturethesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/249752/1/ntu-101-R99543034-1.pdf