本文是針對在電子設備冷卻系統中以矩形渠道內裝置兩分離發熱元件的三維共軛熱傳數值研究。在紊流統御方程式，是採用控制體積法為基礎，配合有限差分法及冪次法則來解著名的 紊流模式與其相關之牆函數來描述紊流結構。
數值計算採用以下變數，雷諾數Re ，流線方向無因次兩元件間之距離S/H，跨距方向無因次兩元件間之距離Sh/H，無因次元件離壁面之距離E/H以及發熱元件熱通量 。
數值模擬結果顯示，如同預期，當雷諾數增加，在元件附近的空氣溫度將會下降，且元件之熱散失將更明顯，熱散失最大值發生在元件的角落。擺放位置有流線方向及跨距方向。元件跨距方向排列比流線方向排列有較佳的熱傳效率。本研究提供了典型的電子設備冷卻系統之設計與最佳化的參考。

關鍵詞:紊流；共軛熱傳；數值模擬

This study present the three-dimensional conjugate heat transfer in a rectangular duct with two discrete flush-mounted heat component in the context of cooling of electronic equipments. The turbulent governing equations are solved by a control-volume-based finite-difference method with power law scheme and the well know turbulence model and its associate wall function are used to describe the turbulent structure.
Numerical computations have been conducted with variations of Reynolds number Re, dimensionless streamwise spacing between components S/H, dimensionless spanwise spacing between components Sh/H, dimensionless distance to the side wall E/H and the heat flux from heat components.
The results of the numerical simulation show that, as expected, an increase in Re resulted in lower air temperature in the vicinity of the heat components, which increases the rate of heat removal from the protruding heat components, the maximum heat removal around the components corner. Interest lies in both streamwise and spanwise separation of components. The spanwise arrangement of heat components had in general a better heat transfer performance form basis for the design and optimization
of the cooling arrangement for typical electronic system.

Keywords: turbulent flow, conjugate heat transfer, numerical simulation

參考文獻

[1] Ramadhyani, S., Moffatt.D.F, and Incropera,F.P., ‘‘Conjugate Heat Transfer From Small Isothermal Heat Sources Embedded in a Large
Substrate,’’ Int. J. Heat Mass Transfer, Vol.28, pp. 1945-1952, 1985.

[2] Ghaddar.N.K., Korczak.K.Z., and MikicB.B., ‘‘Numerical Investigation of Incompressible Flow in Grooved Channels. Part 1: Stability and Self-Sustained Oscillations,’’ J. Fluid Mech., Vol. 163, pp. 99-127,
1986.

[3] Goldstein, Yoo and Chung, “Convevtive Mass Transfer from a Square Cylinder and Its Bass Plate,” Int.J. Heat Mas Transfer, Vol.33, No.1, pp.
9-18, 1990.

[4] Papanicolaou, and Jaluria, ‘‘Transition to a Periodic Regime in Mixed Convection in a Square Cavity,’’ J. Fluid Mech., Vol. 239, pp.
489-509, 1992.

[5] Nigen, and Amon, ‘‘Time-Dependent Conjugate Heat Transfer Characteristics of Self-Sustained Oscillatory Flows in a Grooved Channel,’’ ASME J. Fluids Eng., Vol. 116, pp. 499-507, 1994.

[6] Hwang, and Liou, “Augmented Heat Transfer in a Rectangilar Channel with Pemeable Ribs Mounted on the Wall”, ASME J. Heat Transfer,
Vol. 116, pp. 912-920, 1994.

[7] Nigen, and Amon, ‘‘Time-Dependent Conjugate Heat Transfer Characteristics of Self-Sustained Oscillatory Flows in a Grooved
Channel,’’ J. Fluids Eng., Vol. 116, pp. 449-507, 1994.

[8] Papanicolaou, and Jaluria, ‘‘Mixed Convection From Simulated Electronic Components at Varying Relative Positions in a Cavity,’’
ASME J.Heat Transfer, Vol. 116, pp. 960-970, 1994.

[9] Rahman, and Raghavan, ‘‘Transient Response of Protruding Electronic Modules Exposed to Horizontal Cross Flow,’’ Int. J. Heat Mass
Transfer, Vol. 20, pp. 48-59, 1999.

[10] Garimella, Schiltz, ‘‘Heat Transfer Enhancement in Narrow Channels Using Two and Three-dimensional Mixing Devices, ’’ ASME J. Heat
Transfer, Vol. 117, pp. 590-596, 1995.

[11] Sugavanam, Ortega, and Choi, ‘‘A Numerical Investigation of Conjugate Heat Transfer From a Flush Heat Source on a Conductive Board in Laminar Channel Flow,’’ Int. J. Heat Mass Transfer, Vol. 38,
pp. 2969-2984, 1995.

[12] Jubran, Swiety, Hamdan, ‘‘Convective Heat Transfer and Pressure
Drop Characteristics of Various Array Configurations to Simulate the
Cooling of Electronic Modules,’’ Int. J. Heat Mass Transfer, Vol. 39,
pp. 3519-3529, 1996.

[13] Nakayama, “Forced Convective/Conductive Conjugate Heat Transfer in Microelectronic Equipment,” Annu. Rev. Heat Transfer, Vol. 8, pp.
1-45, 1997.

[14] Chen and Wang, ‘’Experimental Study on the Forced Convective Flow
in a Channel with Heated Blocks on Tandem,’’ Experimental Thermal
and Fluid Science, Vol. 16, pp. 286-298, 1997.

[15] Sathe, and Sammakia, ‘‘A Review of Recent Developments in Some Practical Aspects of Air-Cooled Electronic Packages,’’ ASME J. Heat
Transfer, Vol. 120, pp. 830–839, 1998.

[16] Jaluria, ‘‘Design and Optimization of Thermal Systems,’’
McGraw-Hill,New York, NY, 1998.

[17] Wang, Vafai, ‘‘Heat Transfer and Pressure Loss Characterisation in a Channel with Discrete Flush-mounted and Protruding Heat Sources,’’
Experimental Heat Transfer, Vol. 12, pp. 1-16, 1999.

[18] Young, Vafai, ‘‘Experimental and Numerical Investigation of Forced Convective Characteristics of Array of Channel Mounted Obstacles,’’
ASME J. Heat Transfer, Vol. 121, pp.34-42, 1999.

[19] Nicolas, Luijkx, and Platten, ‘‘Linear Stability of Mixed Convection Flows in Horizontal Rectangular Channels of Finite Transversal Extension Heated From Below,’’ Int. J. Heat Mass Transfer, Vol. 43,
pp. 589-610, 2000.

[20] Rachedi, Chikh, “Enhancement of Electronic Cooling by Insertion of
Foam Materials,” Heat Mass Transfer Vol.37, 371-378, 2001.

[21] Qinghua Wang and Yogesh Jaluria, ‘’Instability and Heat Transfer in Mixed Convection Flow in a Horizontal Duct With Discrete Heat
Sources,’’ Numer. Heat Transfer, Vol. 42, pp. 445-463, 2002.

[22] Qinghua Wang and Yogesh Jaluria, “Three-Dimensional Conjugate Heat Transfer in a Horizontal Channel With Discrete Heating,” ASME
J. Heat Transfer, Vol. 126, pp. 642-647, 2004.

[23] Tunc Icoz, Yogesh Jaluria, “Design of Cooling Systems for
Electronic Equipment Using Both Experimental and Numerical
Inputs,” ASME. J. Electronic Packaging, Vol. 126, pp. 465-471,
2004.

[24] Abdelkader Korichi, Lounes Oufer, “Numerical Heat Transfer in a
Rectangular Channel with Mounted Obstacles on Upper and Lower
Walls,” Int. J. Thermal Sciences, Vol. 44, pp. 644-655, 2005.

[25] Bhowmik, Tso, Tou, “Analyses of Convection Heat Transfer From
Discrete Heat Sources in a Vertical Rectangular Channel,” ASME. J.
Electronic Packaging, Vol. 127, pp. 215-222, 2005.

[26] Launder, and Spalding, “The Numerical Computation of Turbulent Flow,” Computer Method in AppLied Mechanics and Engineering, Vol.
3, pp. 269-289, 1972.

[27] Jayatilleke, “The Influence of Prandtl Number and Surface Roughness on the Resistance of the Laminar Sublayer to Momentum and Heat
Transfer,” Prog. Heat Mass Transder, Vol. 1, pp. 193-329, 1969

[28] Patankar, “Numerical Heat Transfer and Fluid Flow, ” McGraw-hill,
New York,1980