以ABAQUS探討熱探針法之試驗變因

Discussing the factors of thermal probe method with ABAQUS

游忠霖(Chung-lin Yu)

指導教授 ： 田永銘

國立中央大學/工學院/土木工程學系/碩士(2007年)

摘要

本研究根據熱探針法之試驗原理，藉由有限元素分析軟體(ABAQUS)，以合理的分析條件及適當的材料參數進行數值模擬，透過與理論解之比較，驗證數值模式之準確性與適用性。接著，逐一探討熱探針法之試驗變因(試體尺寸、淨空、填充導熱泥及輸入電壓等問題)，並配合張家銘(2006)之試驗結果，推求準確之量測值。最後進行材料之參數研究及非等向性岩石之數值模擬，以作為往後實驗者之考量依據。
數值結果顯示，試體之寬徑比應達12.5以上，以避免邊界效應之影響；隨著淨空值增加，會造成低估試體熱傳導係數，且由等值線圖可知，熱傳遞範圍明顯減少，建議填充適當之導熱泥；導熱泥使用應考量待測物之熱傳導係數，不宜填充過差而影響熱源傳遞；電壓輸入量不影響試體之熱傳導係數。參數研究方面，熱源材料比熱或密度對升溫曲線前半部(0～100秒)影響程度最大，建議採用100秒後直線段推求熱傳導係數；相同接觸熱阻條件下，接觸介面厚度較高者填充高熱導性之導熱泥，將提升試體熱傳導係數。
非等向性岩石之數值結果可知，數值模擬證實層狀岩石可等值為橫向等向性岩石；橫向等向性岩石不同異向性比之探討，數值解與Laplace方程式理論解皆有良好的一致性。

關鍵字

橫向等向性 ； 接觸熱阻 ； 等值線圖 ； ABAQUS ； 熱探針法

並列摘要

According to the experimental principle of thermal probe method, the research adopted the finite element analysis (ABAQUS), it carried on the numerical simulation with rational analysis condition and appropriate materal parameters. Through the comparison with theoretical solution, verify the accuracy and suitability of numerical model. Then, some factors of thermal probe method are investigated, including the relative size of the specimen, clearance, type of thermal grease, and inputting the voltage etc., and cooperate with the result of the experiment by Chang(2006) to inquire into the accurate value. Finally, it carried on parameter research and numerical simulation of non-isotropic rock, in order to take them into account for test subsequently.
The numerical result showed that the aspect ratio of the specimen up to 12.5, avoid the influence of boundary effect. If clearance increases, it will underestimate thermal conductivity of the specimen. According to the contour plot, the range of heat transfer will reduce obviously. So numerical result indicated that it need to pack the appropriate thermal grease. The respect of using thermal grease, it should be consider the thermal conductivity of the specimen, not pack too bad to influence the heat transmission. The value of inputting voltage will not influence the thermal conductivity of the specimen. The respect of parameter research showed that the specific heat or density of heat source material causes heavy influence on the range of 0~100 seconds in temperature rise curve. So it suggested to adopt the straight line section after 100 seconds to inquired into thermal conductivity. Under the same thermal resistivity, if the thickness of interface is thicker to pack higher thermal conductivity of grease, it will improve thermal conductivity of the specimen.
The numerical result of non-isotropic rock showed that the numerical simulation verifies two-phase layered rock can be equivalent to transversely isotropic rock. The discussion of transversely isotropic rock at anisotropic ratio, it can find that numerical solution well agreed with theoretical solution of Laplace’s equation.

並列關鍵字

contour plot ； ABAQUS ； transversely isotropic rock ； thermal probe method ； thermal resistivity

參考文獻

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