本研究係利用CFD模擬5G天線陣列之液體冷卻散熱器的內部流道設計與流道內流體有無相變化之比較。首先，利用驗證原型進行3種流道設計比較，再來利用前者得出之結果進行全尺寸模擬，最後再以驗證原型進行二相流模擬。在所有模擬中，選用水作為工作流體，紊流模型採用k-ε標準型或k-ω標準型，並且有考慮共軛熱傳。在驗證原型模擬中，以雙進出水口之流道設計溫度表現最佳，再將此設計放入全尺寸模擬，比較不同之進水溫度與流量。最終研究結果發現，彎曲次數愈少之流道構型，能有效減少流體滯留現象，進而增強散熱效果，且進水口溫度與散熱效能成反比、流量與壓差成正比。而若在相同流道設計下以兩相流來進行散熱，因其相變化所需之潛熱，讓流體所能吸收之熱量增加，使散熱器可以獲得更佳的散熱效果。

This research uses CFD to simulate the comparison of the internal flow channel design of the liquid cooling radiator of the 5G antenna array and the phase change of the fluid in the flow channel. First, use the verification prototype to compare the three pipeline designs, then use the results of the former to perform full-scale simulation, and finally use the verification prototype to perform two-phase flow simulation. In all simulations, water is selected as the working fluid, and the turbulence model adopts standard k-ε or standard k-ω, and considers conjugate heat transfer. In the prototype simulation, the double inlet and outlet pipe design temperature performed the best, and then put this design into a full-scale simulation to compare different inlet water temperatures and flow rates. The final research results found that the flow channel configuration with fewer turns can effectively reduce fluid retention, thereby enhancing the heat dissipation effect, and the inlet temperature is inversely proportional to the heat dissipation efficiency, and the flow rate is proportional to the pressure difference. However, if two flows are used for heat dissipation under the same flow channel design, a better heat dissipation effect can be obtained.

目錄
第一章 緒論	1
1.1 前言	1
1.1.1 5G	1
1.1.2 散熱	4
1.2 關鍵字分析	6
1.3 文獻回顧	8
1.4 研究動機	16
第二章 數學與理論模式	17
2.1 概論	17
2.2 FLUENT	18
2.3 基本假設	20
2.3.1 無相變化模擬	20
2.3.2 有相變化模擬	20
2.4 統御方程式	20
2.5 k-ɛ紊流模型方程式	22
2.6 k-ω紊流模型方程式	24
2.7 熱傳簡介	25
2.8 多相流模型概論	28
2.9 有限體積法	37
第三章 數值計算方法	38
3.1 模型建立	38
3.1.1 驗證原型模擬	38
3.1.2 全尺寸模擬	41
3.1.3	相變化模擬	43
3.2 網格建立	44
3.3 邊界條件給定	45
3.4求解器設定	46
3.5 求解步驟	47
第四章 結果與討論	49
4.1 數值驗證	49
4.1.1 無相變化模擬之數值驗證	49
4.1.2 相變化模擬之數值驗證	53
4.3 網格獨立性分析	54
4.3 結果	56
4.3.1 驗證原型模擬	56
4.3.2 全尺寸模擬	67
4.3.3 相變化模擬	73
第五章 總結與未來展望	79
5.1 總結	79
驗證原型模擬	79
全尺寸模擬	81
相變化模擬	83
5.2 建議與未來展望	86
參考文獻	87
附錄A	92

 
圖目錄
圖 1多層式網路	2
圖 2 Massive MIMO示意圖	3
圖 3 Laitinen研究之散熱器模型	9
圖 4 Laitinen等人研究之數值模型圖	10
圖 5 Yasser與Ahmed研究之數值模擬結果圖	12
圖 6 Bandar、Luiz與Hussam研究之數值模擬圖(R134a)	15
圖 7 FLUENT結構圖	19
圖 8驗證原型物理模型	38
圖 9 type1構型	40
圖 10 type2構型	40
圖 11 type3構型	40
圖 12全尺寸物理模型	41
圖 13全尺寸流道設計圖	42
圖 14全尺寸對稱模型	42
圖 15相變化模擬之延伸計算域	43
圖 16全尺寸模擬之進口區域網格	44
圖 17流程圖	48
圖 18數值驗證物理模型	50
圖 19 Laitinen, Alpo.模型之速度場(單位：m/s)	51
圖 20數值模擬之速度場(單位：m/s)	51
圖 21 Laitinen, Alpo.模型之流體區溫度場(單位：K)	52
圖 22數值模擬之流體區溫度場(單位：K)	52
圖 23相變化模擬之數值驗證模型	53
圖 24壓力梯度與乾度之折線圖(模擬與實驗)	54
圖 25網格獨立性分析圖	55
圖 26 case1之速度場(單位：m/s)	58
圖 27 case2之速度場(單位：m/s)	58
圖 28 case5之速度場(單位：m/s)	59
圖 29 case6之速度場(單位：m/s)	59
圖 30 case9之速度場(單位：m/s)	60
圖 31 case10之速度場(單位：m/s)	60
圖 32 case1之晶片溫度圖(單位：K)	61
圖 33 case2之晶片溫度圖(單位：K)	61
圖 34 case3之晶片溫度圖(單位：K)	62
圖 35 case4之晶片溫度圖(單位：K)	62
圖 36 case5之晶片溫度圖(單位：K)	63
圖 37 case6之晶片溫度圖(單位：K)	63
圖 38 case7之晶片溫度圖(單位：K)	64
圖 39 case8之晶片溫度圖(單位：K)	64
圖 40 case9之晶片溫度圖(單位：K)	65
圖 41 case10之晶片溫度圖(單位：K)	65
圖 42 case11之晶片溫度圖(單位：K)	66
圖 43 case12之晶片溫度圖(單位：K)	66
圖 44 case1之速度場(單位：m/s)	69
圖 45 case3之速度場(單位：m/s)	69
圖 46 case5之速度場(單位：m/s)	70
圖 47 case1之晶片溫度圖(單位：K)	70
圖 48 case2之晶片溫度圖(單位：K)	71
圖 49 case3之晶片溫度圖(單位：K)	71
圖 50 case4之晶片溫度圖(單位：K)	72
圖 51 case5之晶片溫度圖(單位：K)	72
圖 52 case6之晶片溫度圖(單位：K)	73
圖 53 case1之流道內部截面乾度圖	75
圖 54 case2之流道內部截面乾度圖	76
圖 55 case1之晶片溫度圖	76
圖 56 case2之晶片溫度圖	77
圖 57 case3之晶片溫度圖	77
圖 58 case4之晶片溫度圖	78
圖 59 驗證原型各case之晶片最高溫(單位：K)	80
圖 60 驗證原型各case之晶片溫差(單位：K)	80
圖 61全尺寸模擬兩種進口溫度下晶片最高溫與不同流量之折線圖	81
圖 62全尺寸模擬兩種進口溫度下晶片溫差與不同流量之折線圖	82
圖 63全尺寸模擬兩種進口溫度下壓差與不同流量之折線圖	82
圖 64有/無相變化模擬之晶片最高溫與流量比較圖	84
圖 65有/無相變化模擬之晶片溫差與流量比較圖	84
 
 
表目錄
表 1 fifth generation technology mobile communication歷年相關文獻篇數	7
表 2 5G heat transfer CFD歷年相關文獻篇數	7
表 3數據常規化比較表	8
表 4驗證原型各case之參數表	57
表 5全尺寸模擬各case之參數表	67
表 6相變化模擬各case之參數表	75

[1] Gubbi, J., Buyya, R., Marusic, S., & Palaniswami, M. (2013). Internet of Things (IoT): A vision, architectural elements, and future directions. Future generation computer systems, 29(7), 1645-1660.
[2] Rappaport, T. S. (2016). Spectrum frontiers: The new world of millimeter-wave mobile communication. Invited keynote presentation, The Federal Communications Commission (FCC) Headquarters, 10.
[3] Rappaport, T. S., Sun, S., Mayzus, R., Zhao, H., Azar, Y., Wang, K., ... & Gutierrez, F. (2013). Millimeter wave mobile communications for 5G cellular: It will work!. IEEE access, 1, 335-349.
[4] Rappaport, T. S., Xing, Y., MacCartney, G. R., Molisch, A. F., Mellios, E., & Zhang, J. (2017). Overview of millimeter wave communications for fifth-generation (5G) wireless networks—With a focus on propagation models. IEEE Transactions on antennas and propagation, 65(12), 6213-6230.
[5] Fettweis, G. P. (2014). The tactile internet: Applications and challenges. IEEE Vehicular Technology Magazine, 9(1), 64-70.
[6] Mecklenbrauker, C. F., Molisch, A. F., Karedal, J., Tufvesson, F., Paier, A., Bernadó, L., ... & Czink, N. (2011). Vehicular channel characterization and its implications for wireless system design and performance. Proceedings of the IEEE, 99(7), 1189-1212.
[7] Gozálvez, J., Sepulcre, M., & Bauza, R. (2012). IEEE 802.11 p vehicle to infrastructure communications in urban environments. IEEE Communications Magazine, 50(5), 176-183.
[8] Bhushan, N., Li, J., Malladi, D., Gilmore, R., Brenner, D., Damnjanovic, A., ... & Geirhofer, S. (2014). Network densification: the dominant theme for wireless evolution into 5G. IEEE Communications Magazine, 52(2), 82-89.
[9] Maeder, A., Rost, P., & Staehle, D. (2011, August). The challenge of M2M communications for the cellular radio access network. In Proc. Würzburg Workshop IP, Joint ITG Euro-NF Workshop “Vis. Future Gener. Netw.” EuroView (pp. 1-2).
[10] Nikravesh, A., Guo, Y., Qian, F., Mao, Z. M., & Sen, S. (2016, October). An in-depth understanding of multipath TCP on mobile devices: Measurement and system design. In Proceedings of the 22nd Annual International Conference on Mobile Computing and Networking (pp. 189-201).
[11] Deng, S., Netravali, R., Sivaraman, A., & Balakrishnan, H. (2014, November). WiFi, LTE, or both? Measuring multi-homed wireless Internet performance. In Proceedings of the 2014 Conference on Internet Measurement Conference (pp. 181-194).
[12] Andrews, J. G., Buzzi, S., Choi, W., Hanly, S. V., Lozano, A., Soong, A. C., & Zhang, J. C. (2014). What will 5G be?. IEEE Journal on selected areas in communications, 32(6), 1065-1082.
[13] 方士豪。林敬衒。劉俊男 & 魏鴻富 (2016)。5G 小型基地台關鍵元件與平台之探索。電腦與通訊(168)26-33。
[14] Aslan, Y., Puskely, J., Janssen, J. H. J., Geurts, M., Roederer, A., & Yarovoy, A. (2018). Thermal-aware synthesis of 5G base station antenna arrays: an overview and a sparsity-based approach. IEEE Access, 6, 58868-58882.
[15] Tomasic, B., Wisniewski, D., Schmier, R., Steffen, T., & Phillips, G. (2019, July). Cold Plate Design, Fabrication, and Demonstration for High-Power Ka-Band Active Electronically Scanned Arrays. In 2019 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting (pp. 35-36). IEEE.
[16] Liu, Y., & Yang, Y. (2012, August). Numerical Simulation on the Water-cooled Heat Sink for High-power Semiconductor. In Proceedings of the 2012 International Conference on Computer Application and System Modeling. Atlantis Press.
[17] Laitinen, A. (2018). Computational fluid dynamics simulations of liquid cooling for electronics.
[18] Laitinen, A., Saari, K., Kukko, K., Peltonen, P., Laurila, E., Partanen, J., & Vuorinen, V. (2020). A computational fluid dynamics study by conjugate heat transfer in OpenFOAM: A liquid cooling concept for high power electronics. International Journal of Heat and Fluid Flow, 85, 108654.
[19] Al-Waaly, A. A., Paul, M. C., & Dobson, P. (2017). Liquid cooling of non-uniform heat flux of a chip circuit by subchannels. Applied Thermal Engineering, 115, 558-574.
[20] Chiu, H. C., Jang, J. H., Yeh, H. W., & Wu, M. S. (2011). The heat transfer characteristics of liquid cooling heatsink containing microchannels. International Journal of Heat and Mass Transfer, 54(1-3), 34-42.
[21] Yasser, Z. K., & Hamad, A. J. (2019). Experimental and Numerical Analyses of R134a Flow Boiling Heat Transfer Characteristics in an Evaporator Tube of Refrigeration System. International Journal of Air-Conditioning and Refrigeration, 27(03), 1950024.
[22] Cuan, Z., & Chen, Y. (2017). Analyze of laminar flow and boiling heat transfer characteristics of R134a in the horizontal micro-channel under low temperature condition. Procedia Engineering, 205, 2933-2939.
[23] Chen, L., Li, X., Xiao, R., Lv, K., Yang, X., & Hou, Y. (2020). Flow Boiling of Low-Pressure Water in Microchannels of Large Aspect Ratio. Energies, 13(11), 2689.
[24] Gao, L., Zhang, L., Ma, Z., Xu, C., Xiao, Z., & Du, M. (2012, March). The Numerical Simulation of Flow and Boiling Heat Transfer of Two Phases in Horizontal Tube. In 2012 Asia-Pacific Power and Energy Engineering Conference (pp. 1-4). IEEE.
[25] Wu, H. L., Peng, X. F., Ye, P., & Gong, Y. E. (2007). Simulation of refrigerant flow boiling in serpentine tubes. International Journal of Heat and Mass Transfer, 50(5-6), 1186-1195.
[26] Greco, A., & Vanoli, G. P. (2006). Experimental two-phase pressure gradients during evaporation of pure and mixed refrigerants in a smooth horizontal tube. Comparison with correlations. Heat and mass transfer, 42(8), 709-725.
[27] Fadhl, B., Wrobel, L. C., & Jouhara, H. (2015). CFD modelling of a two-phase closed thermosyphon charged with R134a and R404a. Applied Thermal Engineering, 78, 482-490.
[28] Cuan, Z., & Chen, Y. (2017). Analyze of laminar flow and boiling heat transfer characteristics of R134a in the horizontal micro-channel under low temperature condition. Procedia Engineering, 205, 2933-2939. 
[29] Gholampooryazdi, B., Hämmäinen, H., Vijay, S., & Savisalo, A. (2017, November). Scenario planning for 5G light poles in smart cities. In 2017 Internet of Things Business Models, Users, and Networks (pp. 1-7). IEEE.
[30] Zhang, H. Y., Pinjala, D., & Teo, P. S. (2003, December). Thermal management of high power dissipation electronic packages: From air cooling to liquid cooling. In Proceedings of the 5th Electronics Packaging Technology Conference (EPTC 2003) (pp. 620-625). IEEE.
[31] INC, A. (2013). ANSYS Fluent Theory Guide 15.
[32] 李人憲 (2008)。有限體積法基礎。北京：國防工業出版社。