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系統識別號 U0026-0812200915214554
論文名稱(中文) 濕砂模與金屬界面之熱傳模式研究暨鑄造充填的模擬分析
論文名稱(英文) Study on Heat Transfer Models at Mold-Metal Interface and Filling Simulation for Green Sand Mold Casting
校院名稱 成功大學
系所名稱(中) 工程科學系碩博士班
系所名稱(英) Department of Engineering Science
學年度 97
學期 2
出版年 98
研究生(中文) 孫憲琪
研究生(英文) Hsien-chi Sun
電子信箱 sun@hflow.es.ncku.edu.tw
學號 N9890114
學位類別 博士
語文別 中文
論文頁數 128頁
口試委員 口試委員-林健正
口試委員-黃登淵
口試委員-周榮華
口試委員-黃明哲
指導教授-趙隆山
中文關鍵字 砂模鑄造  模與金屬界面  熱傳分析  反算法  間隙 
英文關鍵字 heat transfer analysis  sand mold casting  gap  mold-metal interface  inverse method 
學科別分類
中文摘要 在濕砂模鑄造過程之熱傳模式分析中,砂模與金屬界面熱傳情形是一關鍵性的問題,若無法妥善地處理此界面條件,會直接影響分析的結果。由於濕砂模與鑄件間非為緊密接觸,在模與金屬界面之熱傳方析中,需要一界面熱傳係數h來估算金屬的界面熱束,但是界面熱傳係數是一個未知值,無法單純以實驗或理論的方法獲得,目前的研究都是使用逆運算法算出界面熱傳係數。不過在金屬凝固時之潛熱釋放與濕砂模中之水份的汽化和水蒸氣之凝結會造成溫度計算的困難,如果在凝固時有過冷產生,其計算的困難度就更高,因此本文提出總容量法、外插法、修正總容量法和銅塊法,以簡易之方式估算出砂模與金屬界面熱通量及界面熱傳係數,以利於鑄造凝固過程的熱傳分析。並利用FIDAP軟體模擬分析整個鑄件鑄造過程,在凝固熱傳分析方面可以驗證修正總容量法、總容量法和外插法的可行性。另外,也運用FIDAP模擬分析鑄件在澆注時的流場和充填情形,可作為澆鑄溫度和速度與排氣設計的參考,因而可避免產生充填不足或孔洞等缺陷。
英文摘要 In the heat-transfer analysis of a green sand mold casting process, how to grasp the heat-transfer condition at the sand-mold/metal interface is a key problem. Not manipulated properly, it will directly affect the final result of the analysis. Because it is not perfect contact at the interface, the analysis needs an interfacial heat transfer coefficient to compute the heat fluxes from the metal to the sand mold at the interface. The heat transfer coefficient for a given casting process is unknown. No general formulas or easy ways can be applied to obtain the heat transfer coefficient for any kinds of mold/metal interface. In the literature, inverse methods were generally applied to estimate the interfacial heat transfer coefficient. However, the latent-heat release of metal solidification and the evaporation heat of moisture and the condensation of vapor in the sand mold make the calculations of inverse methods difficult to compute interfacial heat transfer coefficients, especially for those solidification processes having a significant undercooling and recalescence phenomena. To overcome this difficulty, the lump capacitance and extrapolation and modified lump capacitance and copper chunk methods are proposed in this study to calculate the interfacial heat transfer coefficient for the casting process in a green sand mold. Moreover, the resulting interfacial heat transfer coefficients were put into the FIDAP software to compute the temperature fields of casting during the solidification processes. The computed complete solidification time and cooling curves are quite similar to the experimental ones. Besides, the FIDAP simulation of a filling process can help us to understand the flow field during the process, which can assist the mold design and the quality control of a casting process.
論文目次 摘要 I
英文摘要 II
誌謝 IV
目錄 V
圖目錄 IX
符號說明 XIV
第一章 緒論 1
第二章 理論與數值分析 9
2-1界面熱傳係數之分析 10
2-2鑄件表面溫度之逆運算法 11
2-3 金屬界面熱束之Beck逆運算法 13
2-3-1直接問題 13
2-3-2 Beck逆運算的處理模式 15
2-4總容量法 18
2-5修正總容量法 19
2-6銅塊法 21
2-7潛熱效應之計算方法 21
2-7-1純金屬(Al) 21
2-7-2鋁合金(A356) 26
2-7-3錫鉛合金( Sn-20wt%Pb ) 27
2-8 FIDAP數值分析方法 29
2-8-1溫度場數值分析 29
2-8-2流場數值分析 30
第三章 實驗設備與方法 31
3-1鑄造實驗設備 31
3-1-1熱電偶點焊與氫氧焰氣焊設備 31
3-1-2混砂造模設備 31
3-1-3熔解金屬設備 32
3-1-4溫度擷取設備 32
3-2鑄模之設計 32
3-2-1流路系統 32
3-2-2模型之設計與作 33
3-3實驗方法與步驟 33
3-3-1濕砂模鑄造實驗方法與步驟 33
3-3-2量測鑄件與砂模溫度分佈的方法 35
3-3-3合模與澆鑄 36
第四章 結果與討論 37
4-1鑄件之溫度量測 37
4-1-1純金屬鋁 38
4-1-2 A356鋁合金 39
4-1-3 Sn-20wt%Pb合金 40
4-2金屬界面溫度之分析 40
4-2-1逆運算法與外插法 41
4-2-2銅塊法 41
4-3金屬界面熱束之分析 41
4-3-1 Beck逆運算法 42
4-3-2總容量法(Lump capacitance method) 44
4-3-3修正總容量法(Modifiied lump capacitance method) 46
4-3-4銅塊法 47
4-4模與金屬界面熱傳係數之分析 47
4-5 FIDAP 模擬分析 51
4-5-1鑄件溫度場分析 51
4-5-2鑄件充填流場分析 53
第五章 結論 55
參考文獻 58
附錄A性質表 107
附錄B 溫度場之差分方程式 108
附錄C史蒂芬問題 112
附錄D錫鉛合金之潛熱式推導 119
附錄E天空線存取模式與LU分解法 122
附錄F流體體積法 (VOF法) 127
自述 128
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