臺灣博碩士論文加值系統

本研究是針對導熱係數量測不準做討論，其量測系統是透過兩片厚度不同但材質相同的測試片與三塊相同導熱係數的圓柱經由串聯方式組成，在外圍利用隔熱棉包覆著參考圓柱使其為絕熱狀態。該設備經由手動或是外接電腦設定加熱溫度直到溫度達到穩態的狀態時，即可擷取溫度並計算材料的導熱係數。材料的導熱係數是依據傅立葉定律推算出修正比較法；此法是假設測試片與圓柱所接觸的每一面之接觸面熱傳係數均為相同，利用熱阻原理所推導的公式算出材料之導熱係數。
經由實驗量測結果與實際材料的導熱係數的比較發現兩者有相當大的差異。造成差異的原因為接觸熱阻不相等和隔熱棉並非在絕熱條件下量測。為了探索其原因，本研究使用熱阻理論與有限元素分析法計算溫度分佈，希望能重現實驗的結果。此外，使用膜厚量測計來量測膜厚並計算出接觸面熱傳係數，透過理想的熱阻模型和有限元方法計算的溫度分佈。結果顯示，此兩種方式無法重現量測結果。其原因在於有顯著的熱量從橫向流失；隔熱棉的熱傳性質未能有效掌握是分析失敗的原因。

This study discusses the cause of the inaccuracy for a Thermal Conductivity Measurement System, which is composed of two test discs of the same material with different thickness and three identical copper cylinders assembled in series. The serial assembled test samples and standard copper cylinders are insulated with glass wool to ensure an adiabatic condition. The temperature setup and measurement can be made manually or by computer. The thermal conductivity is calculated using the modified comparison method based on Fourier’s law. This modified comparison method assumes that the four thermal contact resistance are equal. Significant errors may result from this assumption.

There are significant differences in the thermal conductivity between the measured results and the actual value. This may be due to the fact that the thermal contact resistances are not equal, and that the glass wool enclosure is not thermal insulation. To explore the cause, this study uses the ideal thermal resistance theory and finite element method in a hope to reproduce the experimental results. We use a film-thickness gauge to measure the film-thickness and than calculate the heat transfer coefficient of the contact surface. With the heat transfer coefficient of contact surface, we are able to calculate the temperature distribution using the ideal thermal resistance model and finite-element method. This study shows that both models cannot reproduce the temperature distribution of the measurement system. We find that the significant amount of heat is lost from the lateral direction. The thermal properties of glass wool is not property modeled causing the difference between the simulation and measurement.

摘要 i
Abstract ii
致謝 iii
目錄 iv
表目錄 v
圖目錄 vi
符號表 viii
第一章 　緒論與研究原理 1
第二章 　導熱係數設備 10
2.1 導熱係數原理 10
2.2 導熱係數量測設備 13
2.3 導熱係數量測 22
第三章 　數值模擬分析軟體 28
3.1 SALOME-MECA 28
3.2 前處理器介紹 28
3.3 處理器介紹 30
3.4 後處理器介紹 33
第四章 　建模及分析 34
4.1 幾何外形建構 35
4.2 網格點建立 38
4.3 邊界條件設定 43
第五章 結果與討論 46
5.1 膜厚量測 47
5.2 理論熱阻公式 48
5.3 數值模擬分析 50
第六章 結論 58
參考文獻 59
附錄A SALOME-MECA指令 61
A.1 Mesh模組指令介紹 61
A.2 Code_Aster運算訊息檔 65
附錄B 標準銅柱幾何外型建構 67
附錄C 膜厚計簡介與使用方法 70
附錄D 相關發表論文資料 71

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