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題 名 | 金屬永久模具中D型冷卻管內冷卻水的沸騰現象=Boiling Phenomena of Cooling Water within D-shaped Cooling Channel in the Permanent Mold |
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作 者 | 陳柏森; 許富淵; 林惠娟; 吳崇勇; | 書刊名 | 鑄造工程學刊 |
卷 期 | 38:4=155 2012.12[民101.12] |
頁 次 | 頁19-31 |
分類號 | 472.2 |
關鍵詞 | 冷卻水; 熱通量; 熱傳係數; 金屬永久模具; Water coolant; Heat flux; Heat transfer coefficient; Permanent mold; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究是進行永久模具中,D型冷卻管內,冷卻水的沸騰現象的探討。並且,採用具有週期性的加熱方式:高溫為1573K維持0.5ms,低溫473K維持了49.5ms,在1.5秒內,共計30個週期。發現,冷卻水的流速若低於一臨界流速(或流量)時,會有沸騰情況。當沸騰(雙相)時,系統給冷卻水加熱的能力(熱傳係數) 以及 冷卻水吸收熱的能力(熱通量)兩者皆會比無沸騰(單相)時數值還高。過冷度的增加會影響到初始沸騰時間延後。並且,熱通量與熱傳係數的關係圖中的斜率可以用來表示冷卻水帶走系統熱的能力。斜率正值越大,則指冷卻水從系統中帶走的熱越多,即冷卻水帶走熱的能力越好。其可以用來判斷是否有無沸騰,以及區分三種沸騰流譜狀態。 |
英文摘要 | The boiling phenomena of water coolant within D-shaped cooling channel in the permanent mold were studied. In the mold, the heating cycles of a high temperature (1573K) for 0.5ms and a low temperature(473K) for49.5ms, having 30 cycles within 1.5 seconds, was designed.The boiling of water coolant begins as the velocity of flow into the channel is under a critical velocity (or mass flow rate). In the boiling state, the values of heat transfer coefficient (i.e., heating capability to coolant) and heat flux (i.e., heat absorbed capability by coolant) are much greater than those in the un-boiling state. The degree of the subcoolingtemperature affects the initial time for boiling, which is time for bubble nucleate.In the diagram of heat flux as a function of heat transfer coefficient, the value of the slope represents the capability of the coolant removing the heat from the mold system. If the value is a positive one and high, the heat removed from the system is great. It implies that the coolant has great capability to remove heat. This value could be used to classify the states of boiling phenomena, which are boiling nucleation, bubble flow, and plug flow states. |
本系統中英文摘要資訊取自各篇刊載內容。