本研究旨在利用數值方法分析蒸汽腔體的溫度梯度。文中利用拉普拉斯方程式(Laplace equation)定義上下板塊;運用連續方程式、動量方程式、與能量方程式定義蒸汽腔室,並配合熱傳導與熱對流理論設定邊界條件。數值運算方面則使用有限元素分析軟體ANSYS 9.0來模擬解析。模擬的蒸汽腔體尺寸大小為4cm×0.2cm的二維數值分析模型,工作流體假設為過熱蒸汽,解析其不同板塊材質與加熱面積的溫度分佈。 分析中比較銅、鋁、矽三種不同材質板塊的蒸汽腔體,結果顯示熱傳導係數越大的材質,可得到更為均勻的溫度分佈;而在同熱量不同加熱面積的比較中,因加熱面積小造成熱量集中,溫度分佈較不均勻。在散熱面的溫度分佈上可觀察到,蒸汽腔體除了能用於帶走熱量,作為熱傳遞的媒介之外,還能有效地將熱量均勻帶至散熱面,藉由散熱模組散熱,提高散熱效益。
The study investigates thermal performance of vapor chamber heat spreaders by numerical method. Two-dimensional flow and energy equations are solved in the vapor core, along with conduction in the wall. Numerical simulation is studied with the software ANSYS 9.0 to predict the temperature distribution on a 4cm x 0.2cm chamber area with variation in material and heat source size of the spreader. With comparison of the copper, aluminum, and silicon, result shows that wall thermal conductivity is a major factor in such thin, flat spreaders. The spreader performance also degrades with degrade in heat source size due to the heat centralization and uneven temperature distribution. In addition to heat transmission, vapor chamber can also bring heat to cooling surface, and heat sink effectively, and improve capability of heat dissipation.