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.

[1]Knight, R. W., Hall, D. J., Goodling, J. S. and Jaeger, R. C., “Heat Sink Optimization with Application to Micro-channels,” IEEE Trans- actions on Components Hybrids and Manufacturing Technology, Vol. 15, No. 5, pp. 832-842, 1992.
[2]Gopinath, D., Joshi, Y. K. and Azarm, S., “Multi-Objective Place- ment Optimization of Power Electronic Devices on Liquid Cooled Heat Sinks,” Seventeenth IEEE SEMI-THERM Symposium, pp.117 -119, 2001.
[3]Qu, W., Mudawar, I., “Experimental and Numerical Study of Pressure Drop and Heat Transfer in a Single Phase Micro-Channel Heat Sink,” International Journal of Heat and Mass Transfer, Vol. 45, pp. 2549 - 2565, 2002.
[4]Karim, O., Schaeffer, C., Mallet, B., Coyaud, M. and Gimet, E., “Power Module Integrated Cooling Design Using CFD Simulation,” pp. 1925 -1930, 2001.
[5]Dickinson, R., Novotny, S., Vogel, M., Dunn, J., “A System Design Approach to Liquid-Cooled Microprocessors,＂The Eighth Intersoci- ety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp.413-420, 2002.
[6]Ronald, L., Linton and Dereje Agonafer, “Coarse and Detailed CFD Modeling of a Finned Heat Sink”, IEEE Transactionson Components Packaging, and Manufacturing Technology, Vol. 18, No. 13, 1995.
[7]Babus, R. F., Haq, K., Akintunde and Probert, S. D., “Thermal performance of pin fin assembly”, Int. J. Heat and Fluid Flow, 1995.
[8]Andrea de Lieto Vollaro, Stefano Grignaffini, and Franco Guglierm- etti, “Optimum Design of Vertical Rectangular Fin Arrays”, Interna- tional Journal of Thermal Sciences, Vol.38, No.6, 1999.
[9]Bar-Cohen and Rohsenow, W. M. “Thermally optimum spacing of vertical, natural convection cooled, parallel plates”, J. Heat Transfer Vol.106, No.1, pp.116-123, 1984.
[10]Morrison, A. T., “Optimization of Heat Sink Fin Geometries for Heat Sinks in Natural Convection, “ Inter Societv Conference on Thermal Phenomena, pp. 145-148, 1992.
[11]Bar-cohen, A. and Jelinek, M., “Optimum Arrays of Longitudinal, Retangular Fins in Convective Heat Transfer,” Heat Transfer Eng. Vol.6, No.3, pp.68, 1985.
[12]Hans Jonsson and Björn Palm, “Thermal and Hydraulic Behavior of Plate Fin and Strip Fin Heat Sinks Under Varying Bypass Conditions" IEEE Transactions on Components and Packaging Technologies, Vol. 23, No.1, pp.47-54, 2000.
[13]Kamal, K., Sikka, Kenneth, E., Torrance, C. U., Scholler, Salan ova, “Heat Sinks With Fluted and Wavy Plate Fins in Natural and Low Velocity Forced Convection”, IEEE Transactions on Compo- nents and Packaging, Vol. 25, No.2, pp.283-292, 2002.
[14]吳德洋，“散熱座應用於水冷系統之效能評估”，大同大學，機械工程研究所，碩士論文，2003。
[15]Tanda, G., “Natural Convection Heat Transfer From a Staggered Vertical Plate Array, “ ASME Journal of Heat Transfer, Vol. 115., pp.938 -945, 1993.
[16]Lee, S., “How to select a heat sink “, Electronics Cooling, 1995.
[17]Chu, R. C., Hwang, U. P. and Simons, R. E., “Conduction Cooling for an LSI Package: A One-Dimensional Approach”, IBM J. RES.Deve- op. Vol.1, No.1 , 1982.
[18]Bar-Cohen, “Thermal Management of Air and Liquid Cool Mutichip
Modules”, IEEE Transactions on Components Hybrids and Manufa- cturing Technology, Vol.10, No.2 , 1987.
[19]Lee, T. Y. T., Andrews, J.A., Chow, P. and Saums, D., “Compact Liquid Cooling System for Small Moveable Electronic Equipment” , IEEE Transactions on Components Hybrids and Manufacturing Tech., Vol. 15, No.5, 1992.
[20]Vogel, M. R., “Liquid Cooling Performance for a 3D Multichip Mod- ule and Miniature”, Components Packaging and Manufacturing Tec- h. ,Part A, IEEE Transactions on see also Components, Hybrids, and Manufacturing Technology,Vol.18, No.1, pp.68-73, 1995.
[21]Gima, S., Romimura, T., Zhang, X. and Fujii, M., “An Experimental Study on Liquid Cooling of High-Power IC Chips”, Advances in Electronic Packaging , Vol.2, ASME 1999.
[22]Dickinson, R. D., Novotny, S., Vogel, M. and Dunn, J., “A System Approach to Liquid-Cooled Microprocessors”, Thermal and Thermo- mechanical Phenomena in Electronic Systems, pp.413-420, 2002.
[23]Hammoud, J. Y., Zhou and Abazarnia, N., “Effects of the Liquid Inlet Temperature on the Thermoelectric Cooler Performance in a Liquid Thermal System”, Proceedings ICT, 02. Twenty-First International Conference , pp.506-510, 2002.
[24]Zhang, H. Y., Pinjala, D. and Teo, P. S., “Thermal Management of High Power Dissipation Electronic Packages: from Air Cooling to Liquid Cooling”, Electronics Packaging Technology Conference, 2003.
[25]Lee, T. Y., “Design Optimization of an Integrated Liquid-Cooled IGBT Power Module Using CFD Technique”, IEEE Transactions Components and Packaging Technologies, Vol. 23 , No. 1, 2000.
[26]Cengel, Y. A., “Introduction to Thermodynamics and Heat Transfer”, McGraw-Hill, 1997.
[27]Tse, F. S. and Morse, I. E., “Measurement and Instrumentation in Engineering”, Marcel Dekker, Inc, 1989.
[28]Incropera, F. P. and David, P Dewitt, “Fundamentals of Heat and Mass Transfer”, John Wiles & Sons, 2002.
[29]國立清華大學http://ocw.nthu.edu.tw/ocw/upload/2/news/Heatsinks.pdf.
[30]宋志傑，“水冷式散熱座冷卻效益之研究”，大同大學，機械工程研究所，碩士論文，2010。