本研究針對平板式散熱模組，利用實數型基因演算法結合商用熱流分析軟體（CFD-ACE+）進行幾何外形參數最佳化。首先利用熱流分析軟體分別建構正向解全模組及單一流道模組，並進行參數分析，求出不同物理或幾何參數組合下之熱阻值，藉此了解幾何參數對散熱模組性能之影響；同時，架構一風洞實驗進行實驗量測以便獲得熱阻值，以實驗數據驗證正向解全模組與單一流道預測之準確性，其預測結果在合理範圍且穩定。
本研究考慮的條件為下吹式配置，並考慮空氣入口與散熱片頂端存在間隙。在不同速度、間隙、散熱片材料條件下，將散熱模組幾何參數組合（如散熱片厚度、散熱片間距、散熱片高度、散熱模組底板厚度等）視為設計變數，將散熱模組熱阻值視為目標函數，以熱阻值最小化為目的，進行幾何參數組合的最佳化搜尋。研究結果顯示，本研究所提出之最佳化設計架構，可以有效地在不同條件之下，得到最小化熱阻的幾何參數組合。

The study is concerned with optimization of the geometrical parameters with a parallel plate fin heat sink module by integrating the real-coded genetic algorithm（RCGA）with a commercial code, CFD-ACE+, which is regarded as the direct problem solver. Two simulation modules, namely the full module and the single-channel module, are built based on the framework of the commercial code. Firstly, numerical study of the performance of the heat sink has been performed to determine the thermal resistance of the heat sink at various physical and geometrical conditions. Parametric study is performed to evaluate the influence of the geometrical parameters of heat sink. Meanwhile, a wind tunnel has been constructed and experiments have been conducted. The experimental data for the thermal resistance have been collected to confirm the results of numerical simulation. The single-channel simulation module has further been combined with the RCGA method for seeking the optimal combination of designed geometrical parameters, including fin thickness, fin spacing, fin height, base plate thickness, and so on. In this study, the heat sink is referred to an impingement flow configuration and the effect of the gap between the air inlet and the fin tips is considered. The objective function is defined in term of the thermal resistance. The combination of the geometrical parameters is adjusted by the RCGA method such that the thermal resistance of the heat sink can be minimized. Optimal designs are presented for various incoming air velocities, gaps between fan and fin tips, and fin materials. Results show that the present approach is robust and can efficiently lead to the optimal combination of geometrical parameters under various conditions.

[1] R. W. Knight, J. S. Goodling and B. E. Gross, “Optimal thermal design of air cooled forced convection finned heat sinks-experimental verification,” IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 15(5), pp. 754-760, 1992.
[2] R. W. Knight, D. J. Hall, J. S. Goodling and R. C. Jaeger, “Heat sink optimization with application to microchannels,” IEEE Transactions on Components, Hybrids, and Manufacturing Technology, Vol. 15(5), pp. 832-842, 1992.
[3] K. Azar, R. S. McLeod and R. E. Caron, “Narrow channel heat sink for cooling of high powered electronic components,” Proceedings of Eighth Annual IEEE Semiconductor Thermal Measurement and Management Symposium, pp. 12-19, 1992.
[4] S. Lee, “Optimum design and selection of heat sinks,” IEEE Transactions on Components, Packaging, and Manufacturing Technology, Part A, Vol. 18(4), pp. 812-817, 1995.
[5] O. Braunshtein, H. Kalman and A. Ullmann, “Performance and optimization of composed fin arrays,” Heat Transfer Engineering, Vol. 25(4), pp. 4-12, 2004.
[6] J. R. Culham and Y. S. Muzychka, “Optimization of plate fin heat sinks using entropy generation minimization,” IEEE Transactions on Components and Packaging Technologies, Vol. 24(2), pp. 159-165, 2001.
[7] A. Bar-Cohen and M. Iyengar, “Design and optimization of air-cooled heat sinks for sustainable development,” IEEE Transactions on Components and Packaging Technologies, Vol. 25(4), pp. 584-591, 2002.
[8] C. L. Chapman, S. Lee and B. L. Schmidt, “Thermal performance of an elliptical pin fin heat sink,” Proceedings of Tenth IEEE Semiconductor Thermal Measurement and Management Symposium, pp. 24-31, 1994.
[9] P. Teertstra, M. M. Yovanovich, J. R. Culham and T. Lemczyk, “Analytical forced convection modeling of plate fin heat sinks,” Proceedings of Fifteenth Annual IEEE Semiconductor Thermal Measurement and Management Symposium, pp. 34-41, 1999.
[10]M. Saini and R. L. Webb, “Heat rejection limits of air cooled plane fin heat sinks for computer cooling,” IEEE Transactions on Components and Packaging Technologies, Vol. 26(1), pp. 71-79, 2003.
[11]H. Iwasaki and M. Ishizuka, “Forced convection air cooling characteristics of plate fins for notebook personal computers,” IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, pp. 21-26, 2000.
[12]J. A. Visser, D. J. de Kock and F. D. Conradie, “Minimisation of heat sink mass using mathematical optimisation,” Proceedings of Sixteenth Annual IEEE Semiconductor Thermal Measurement and Management Symposium, pp. 252-259, 2000.
[13]C. H. Huang, I. C. Yuan and H. Ay, “A three-dimensional inverse problem in imaging the local heat transfer coefficients for plate finned-tube heat exchangers,” International Journal of Heat and Mass Transfer, Vol. 46(19), pp. 3629-3638, 2003.
[14]W. B. Krueger and A. Bar-Cohen, “Optimal numerical design of forced convection heat sinks,” IEEE Transactions on Components and Packaging Technologies, Vol. 27(2), pp. 417-425, 2004.
[15]謝惠茹，整合電腦輔助分析軟體進行散熱模組最佳化設計，大同大學，碩士論文，2006。
[16]J. P. van Doormaal and G. D. Raithby, “Enhancements of the SIMPLE method for predicting incompressible fluid flows,” Numerical Heat Transfer, Vol. 7(2), pp. 147-163, 1984.
[17]http://www.esi-group.com/
[18]R. D. Mehta and P. Bradshaw, “Design rules for small low speed wind tunnels,” Aeronautical Journal, Vol. 83, pp. 443-449, 1979.
[19]J. H. Holland, Adaptation in natural and artificial systems, University of Michigan Press, Ann Arbor, 1975.
[20]D. E. Goldberg, Genetic algorithms in search, optimization and machine learning, Addison-Wesley, Boston, 1989.
[21]Z. Michalewicz, Genetic algorithms + data structures = evolution programs, Springer-Verlag, New York, 1998.
[22]K. Deb and R. B. Agrawal, “Simulated binary crossover for continuous search space,” Complex Systems, Vol. 9, pp. 115-148, 1995.
[23]R. L. Haupt and S. E. Haupt, Practical genetic algorithms, Wiley-Interscience, New Jersey, 2004.
[24]K. Krishnakumar, “Micro-genetic algorithms for stationary and non-stationary function optimization,” SPIE: Intelligent Control and Adaptive Systems, pp. 289-296, 1989.
[25]F. P. Incropera and D. P. DeWitt, Fundamentals of heat and mass transfer, Wiley, New York, 1996.
[26]ASM Handbook Volume 2, Properties and selection: nonferrous alloys and special-purpose materials, ASM International, 1990.