為因應巨量網路存取的需求所衍生的伺服器散熱問題，本文擬開發1U伺服器適用的CPU液冷式散熱座，首先採用數值模擬方法，找出散熱座的最適鰭片間距，並導入斷續型的鰭片設計，找出適當的分段數，以提高流體的擾動度，並避免過多斷續鰭片增加摩擦力。有鑑於小間距的連續式鰭片和多段分割式鰭片的加工成本較高，基於成本考量，必須在較大鰭片間距及較少分段數下，得到較佳的散熱效能，故導入交錯式設計鰭片，結果發現，在鰭片間距2.5mm的條件下，分割鰭片隨流長度為4段，且交錯排列的狀況下，可以得到比小間距(0.5mm)連續式鰭片更佳的散熱效果。 為了進一步驗證模擬計算結果，本文採用電腦數值控制加工製程實作鰭片間距0.5mm的連續式鰭片以及2.5mm的交錯式鰭片兩種散熱座樣品，並在實驗中量測兩種型式散熱座的散熱性能，再將實際測試數據與模擬計算結果作對照。結果發現，實作樣品與模擬計算結果有著相同的趨勢，且間距2.5mm的交錯式鰭片的散熱性能確實較鰭片間距0.5mm的連續式鰭片散熱座優異。最後，檢討各製程工法的限制與成本，以找出最佳性價比的量產設計參考。 ;In order to solve the thermal issues of servers arising from a large amount of network access, the present effort seeks to develop a liquid cooling CPU heat sink for 1U server. First, numerical analysis was used to find out the best fin space, and then the design of cross-cut pin fin was introduced. As a result, a proper number of the segmented sections was found to enhance the disturbance of flow and to avoid the frictions caused by too many segmented sections. In order to get better thermal performance under larger fin space and less segmented sections to save the cost, staggered fin was proposed to realize the aim. The results showed that with the fin space of 2.5mm and 4 segmented sections, the performance of staggered fin is better than the straight fin with the space of only 0.5mm.
To validate the simulation results, a staggered fin base and a straight fin base were fabricated via CNC machining process. Their thermal performances were measured respectively and then compared with numerical results. The experimental results show a coordinate tendency with numerical simulations and confirmed that the staggered one get better performance. Finally, a review on the limitations and cost of different manufacturing processes was conducted to find the best cost-effective mass production design.
