高热流密度回路型重力热管蒸发器传热特性的数值分析
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摘要
本文首先对热管的历史、发展以及现状作了一些概括和总结，对热管在电子器件尤其是计算机CPU方面的散热问题的文献作了比较详细的综述。对高热流密度电子器件散热，回路型热管散热器是很重要的方式之一。
针对回路型热管散热器，分析其传热过程，蒸发器部分的传热特性研究是主要的，在进行数值模拟计算之前，必须先对问题进行简化，然后再建立合适的物理模型。在建立好物理模型后，对能量方程、动量方程、连续性方程等进行离散，以便于计算。对网格的划分本文采用Gambit，而数值模拟则由CFD软件Fluent来完成。
根据数值计算的结果，对蒸发器的传热特性进行分析，计算所获得的蒸发器底部及其蒸汽出口表面的温度场，计算过程中考虑散热功率、蒸汽饱和温度以及充液量对性能的影响。根据对所获得的温度场的分析得出如下结论：在文中给出蒸发器的尺寸(长×宽×高，65×65×15mm)下，最佳充液量在40％左右，最大散热功率为160W，蒸汽饱和温度较低利于传热性能的改善。在得出蒸发器底面和蒸汽出口表面的平均温度后，运用换热热阻串连模型对各个部分的热阻进行了分析计算，蒸发器的热阻主要集中在发热元件和蒸发器底部之间的接触热阻，占整个蒸发器总热阻的80％左右，其次就是汽—液界面相变换热热阻，从而提出强化传热的一些具体措施，如保持发热元件和蒸发器底部的接触良好以及在热管蒸发段内表面采用烧结金属粉末、加工槽道等措施，以便于进一步改善热管的性能，期望能对热管的设计和优化起一定的指导意义。
The generalization and sum on the history, development and present status of heat pipe are presented at first. The literatures about using heat pipes for heat emission on electronical devices especially on the CPU of computers are summarized.
At first the problems should be simplified. Then the qualifying and right physical models for computing can be constructed. After the model is made, the Energy equations, Momentum equations and Continuity equations should be dispered for programming and computing. In the paper Gambit is selected for grid demarcation and Fluent of CFD Softwares is selected for numerical simulations. The analysis made on the heat transfer characters in the evaporator of Loop Thermosyphon is based on the temperature distribution of the bottom and top of the evaporator. During the computing course, Heat Power, filling ratio of liquid and Saturation Temperature are taken into account. From the temperature distribution the following conclusions are obtained: In the conditions of given size (Length X Width X Height, 65 X 65 X 15mm) the optimum filling ratio of liquid is 40% or so, the maximal Heat power is 160W and the smaller saturation temperature is in favor of the better heat transfer characters. After the average temperature o
f the bottom and top of the evaporator is got, the thermal resistance of each parts of the evaporator can be computed by using linking heat resistance model. Thus some measures of reinforcing heat transfer are advanced for the purpose of improving the heat transfer characters of heat pipe . The above works can be of some value for the design and optimizations of heat pipe.
针对回路型热管散热器，分析其传热过程，蒸发器部分的传热特性研究是主要的，在进行数值模拟计算之前，必须先对问题进行简化，然后再建立合适的物理模型。在建立好物理模型后，对能量方程、动量方程、连续性方程等进行离散，以便于计算。对网格的划分本文采用Gambit，而数值模拟则由CFD软件Fluent来完成。
根据数值计算的结果，对蒸发器的传热特性进行分析，计算所获得的蒸发器底部及其蒸汽出口表面的温度场，计算过程中考虑散热功率、蒸汽饱和温度以及充液量对性能的影响。根据对所获得的温度场的分析得出如下结论：在文中给出蒸发器的尺寸(长×宽×高，65×65×15mm)下，最佳充液量在40％左右，最大散热功率为160W，蒸汽饱和温度较低利于传热性能的改善。在得出蒸发器底面和蒸汽出口表面的平均温度后，运用换热热阻串连模型对各个部分的热阻进行了分析计算，蒸发器的热阻主要集中在发热元件和蒸发器底部之间的接触热阻，占整个蒸发器总热阻的80％左右，其次就是汽—液界面相变换热热阻，从而提出强化传热的一些具体措施，如保持发热元件和蒸发器底部的接触良好以及在热管蒸发段内表面采用烧结金属粉末、加工槽道等措施，以便于进一步改善热管的性能，期望能对热管的设计和优化起一定的指导意义。
The generalization and sum on the history, development and present status of heat pipe are presented at first. The literatures about using heat pipes for heat emission on electronical devices especially on the CPU of computers are summarized.
At first the problems should be simplified. Then the qualifying and right physical models for computing can be constructed. After the model is made, the Energy equations, Momentum equations and Continuity equations should be dispered for programming and computing. In the paper Gambit is selected for grid demarcation and Fluent of CFD Softwares is selected for numerical simulations. The analysis made on the heat transfer characters in the evaporator of Loop Thermosyphon is based on the temperature distribution of the bottom and top of the evaporator. During the computing course, Heat Power, filling ratio of liquid and Saturation Temperature are taken into account. From the temperature distribution the following conclusions are obtained: In the conditions of given size (Length X Width X Height, 65 X 65 X 15mm) the optimum filling ratio of liquid is 40% or so, the maximal Heat power is 160W and the smaller saturation temperature is in favor of the better heat transfer characters. After the average temperature o
f the bottom and top of the evaporator is got, the thermal resistance of each parts of the evaporator can be computed by using linking heat resistance model. Thus some measures of reinforcing heat transfer are advanced for the purpose of improving the heat transfer characters of heat pipe . The above works can be of some value for the design and optimizations of heat pipe.
引文
[1] 谢德仁．《微电子设备的温度控制》．电子机械工程，1991．4
[2] 胡志勇．《当今电子设备冷却技术的发展趋势》．电子机械工程，1999(1)
[3] 庄骏，张红．《热管技术及其工程应用》．化学工业出版社，2000年6月
[4] 邱海平．电子元器件及仪器的热控制技术．北京：电子工业出版社，1991
[5] Gaugler R S. Heat transfer device. U. S. Patent2350348. Dec. 21, 1942, June6, 1944
[6] Trefethen L. On the surface tension pumping of liquid or a possible role of the candlewick in space exploration.G.E.Tech.Info.Serial No.615 D115
[7] Grover G M, Cotter T P And Erikson G F. Structure of very high thermal conductance. J.Appl.Phys. 1964,35(6)
[8] Cotter T P. Theory of heat pipes.Los Alamos Scientific Lab:Report No.LA-3246-MS, 1965
[9] Tien C L, Sun K H. Minimum meniscus radius of heat pipe wicking materials. Int.J.Heat Mass Transfer. 1971,14(11)
[10] 马同泽．《热管》．科学出版社，1983
[11] 曹剑峰，侯增祺，米珉．回路热管在不同姿态下的启动与运行．第八届全国热
管会议论文集，2002年7月，成都，pp65
[12] Lashley C, Krein S, Barcomb P. Deployable Radiators-A Multi-Discipline Approach, Soeity of Automotive Engineers, pp981691,July 1998
[13] Nikitkin M, Cullimore B. CPL and LHP Technologies:What are the Differences. What are the similarities?.Soeity of Automotive Engineers,pp9815487,July 1998
[14] Dickey J T, Peterson G E An Experimental and Analytical Investigation of the Operational Characteristics of a Capillary Pumped Loop, Journal of Thermophysics and Heat Transfer, Vol.8,No.3,1994,pp602-607
[15] Wirsh PJ,Thomas S K. Performance Characteristics of a Stainless Steel/Ammonia Loop Heat Pipe, Journal of Thermophysics and Heat Transfer, Vol. 10,No.3,1996,pp326-333
[16] Maidanik Y F, Fershtater Y F, Solodovnik N N. Design and Investigation of Regulation of Loop Heat Pipes for Terrestrial and Space Applications, Soeity of Automotive Engineers, pp941407,June 1994
[17] Kiseev V M, Belonogov AG., Pogorelov N P. Development of Two-Phase Loops with Capillary Pumps. Soeity of Automotive Engineers, pp972482,July 1997
[18] Bienert WB, Wolf D A. Temperature Control with Loop Heat Pipes:Analytical Model and Test Results. Proceedings of the 9th International Heat Pipe Conference. Los Alamos National Lab,NM, 1995
[19] Mulholland G., Gerhart C, Gluck D, Stanley S. Comparison Between Analytical Predictions and Experimental Data for a Loop Heat Pipe. American Institute of Physics Conference Proceedings 458.edited by M.S.E1-Genk. American Inst.of Physics,New York, 1999,pp805-810
[20] V V Maziuk, A L Rak. Heat Flow Distribution in Capillary Structures of Loop Heat Pipes. 12th International Heat Pipe Conference. May 19-24,2002,Moscow, Kostroma, Russia, voll.A1-5
[21] Jie Yi, Zhen-Hua Liu, Jing Wang. Heat Transfer characteristics of the evaporator section using small helical coiled pipes in a looped heat pipe. Applied Thermal Engineering 23(2003) 89-99
[22] V G Pastukhov, Yu F Maidanik, C V Vershinin, M A Korukov. Miniature loop heat pipes for electronics cooling. 12th International Heat Pipe Conference. May 19-24,2002,Moscow, Kostroma, Russia,vo12. F-2
[23] Satio Y, Mochizuki M, goto K, Nauyen T et al. The application for personal computer using heat pipe technology. 10th IHPC Preprints of Sessions e6 Stuttgart Sep.21～25,1997
[24] 林唯耕，陈绍文．微小化毛细泵吸环路(miniature CPL)应用于笔记本计算机传热之研究．工程热物理学报，Vol23．NO．5，Sep2002
[25] C S Chang, B J Huang,Yuri F Maidanik. Feasibility Study of a Mini LHP for CPU Cooling of a Notebook PC. 12th International Heat Pipe Conference, May 19-24,2002,Moscow, Kostroma,Russia, vo12.F-5
[26] Huang B J. " A network heat pipe for remote heat transport", 12th International Heat Pipe Conference, May 19-24,2002,Moscow, Russia, vo12.F-3
[27] Thang Nguyen, Masataka Mochizuki, et al. Advanced Cooling System Using Miniature Heat Pipes in Mobile PC. IEEE TRANSACTIONS ON COMPONENTS TECHNOLOGY, 23 (1)(2000) pp86-90
[28] Murakami M, Ogushi T, Sakurai Y, Masunoto H, Furukawa M, Imai R. Heat pipe heat sink, in:Proc.6th International Heat Pipe Conference,Grenoble,France, 1987,pp257-261
[29] Peterson G P. Duncan A B, Ahmed A S, Malik A K, Weichold M H. Experimental investigation of micro heat pipes in silcon wafers. Micromechanical Sensors. Actuators and Systems ASME-DEC 32(1991) pp341-348
[30] Peterson G P, Duncan A B. Experimental investigation of micro heat pipes fabricated in silcon wafers. J.Heat Trans, -T ASME 115(8) (1993) 751-576
[31] Peterson G P, Malik A K. Transient response characteristics of vapor deposited micro heat pipe arrays. J.Electron. Pack. 117(3) (1995) 82-87
[32] Malik A K, Peterson G P, Steady-state investigation of vapor deposited micro eat pipe arrays. J.Electron. Pack. 117(3) (1995)75-81
[33] Malik A K, Peterson G P, Weichold M H. On the use of micro heat pipes as an integral part of semi-conductor devices. J.Electron. Pack. 114(4) (1992) 436-442
[34] Khrustalev D, Faghri A. Thermal analysis of a micro heat pipe. J.Heat Trans-T.ASME 116(2)(1994) 189-198
[35] Dr. Altman E I, Mrs.Mukminova M Ia, The Loop Heat Pipe Evaporators theoretical analysis. 12th International Heat Pipe Conference, May 19-24,2002,Moscow, Kostroma,Russia, voll .A2-8
[36] Zhuang Jun. Research on CPU Heat Pipe Coolers, 12th International Heat PipeConference, May 19-24,2002,Moscow, Kostroma, Russia, vo12.F-6
[37] 廖光亚，江村．三维外肋重力热管散热器的实验研究．第八届全国热管会议论文集(成都，2002年7月)
[38] 吴存真，刘光铎合编．《热管在热能工程中的应用》．水利电力出版社，1993
[39] 陶文铨著．计算传热学的近代发展．科学出版社，2001
[40] 陶文铨，数值传热学．西安：西安交通大学出版社，1988．70-72，444，442
[41] Versteeg H K, Malalasekera W. An introduction to computational fluid dynamics. The finite volume method. Essex: Longman Scientific & Technical, 1995.72
[42] M Shiraishi, K Kikuohi and T Yamanishi Inveatigation of Heat Transfer Characteristics of a Two-Phase Closed Thermosyphon.6th Int .Heat Pipe Conf. 1987.
[43] Imura H, Sasaguchi K, Kozaj H. Critical Heat Flux In A Two-Phase Thermosyphon, Int.J.Heat Mass Transfer 26, 8(1983),p1181
[2] 胡志勇．《当今电子设备冷却技术的发展趋势》．电子机械工程，1999(1)
[3] 庄骏，张红．《热管技术及其工程应用》．化学工业出版社，2000年6月
[4] 邱海平．电子元器件及仪器的热控制技术．北京：电子工业出版社，1991
[5] Gaugler R S. Heat transfer device. U. S. Patent2350348. Dec. 21, 1942, June6, 1944
[6] Trefethen L. On the surface tension pumping of liquid or a possible role of the candlewick in space exploration.G.E.Tech.Info.Serial No.615 D115
[7] Grover G M, Cotter T P And Erikson G F. Structure of very high thermal conductance. J.Appl.Phys. 1964,35(6)
[8] Cotter T P. Theory of heat pipes.Los Alamos Scientific Lab:Report No.LA-3246-MS, 1965
[9] Tien C L, Sun K H. Minimum meniscus radius of heat pipe wicking materials. Int.J.Heat Mass Transfer. 1971,14(11)
[10] 马同泽．《热管》．科学出版社，1983
[11] 曹剑峰，侯增祺，米珉．回路热管在不同姿态下的启动与运行．第八届全国热
管会议论文集，2002年7月，成都，pp65
[12] Lashley C, Krein S, Barcomb P. Deployable Radiators-A Multi-Discipline Approach, Soeity of Automotive Engineers, pp981691,July 1998
[13] Nikitkin M, Cullimore B. CPL and LHP Technologies:What are the Differences. What are the similarities?.Soeity of Automotive Engineers,pp9815487,July 1998
[14] Dickey J T, Peterson G E An Experimental and Analytical Investigation of the Operational Characteristics of a Capillary Pumped Loop, Journal of Thermophysics and Heat Transfer, Vol.8,No.3,1994,pp602-607
[15] Wirsh PJ,Thomas S K. Performance Characteristics of a Stainless Steel/Ammonia Loop Heat Pipe, Journal of Thermophysics and Heat Transfer, Vol. 10,No.3,1996,pp326-333
[16] Maidanik Y F, Fershtater Y F, Solodovnik N N. Design and Investigation of Regulation of Loop Heat Pipes for Terrestrial and Space Applications, Soeity of Automotive Engineers, pp941407,June 1994
[17] Kiseev V M, Belonogov AG., Pogorelov N P. Development of Two-Phase Loops with Capillary Pumps. Soeity of Automotive Engineers, pp972482,July 1997
[18] Bienert WB, Wolf D A. Temperature Control with Loop Heat Pipes:Analytical Model and Test Results. Proceedings of the 9th International Heat Pipe Conference. Los Alamos National Lab,NM, 1995
[19] Mulholland G., Gerhart C, Gluck D, Stanley S. Comparison Between Analytical Predictions and Experimental Data for a Loop Heat Pipe. American Institute of Physics Conference Proceedings 458.edited by M.S.E1-Genk. American Inst.of Physics,New York, 1999,pp805-810
[20] V V Maziuk, A L Rak. Heat Flow Distribution in Capillary Structures of Loop Heat Pipes. 12th International Heat Pipe Conference. May 19-24,2002,Moscow, Kostroma, Russia, voll.A1-5
[21] Jie Yi, Zhen-Hua Liu, Jing Wang. Heat Transfer characteristics of the evaporator section using small helical coiled pipes in a looped heat pipe. Applied Thermal Engineering 23(2003) 89-99
[22] V G Pastukhov, Yu F Maidanik, C V Vershinin, M A Korukov. Miniature loop heat pipes for electronics cooling. 12th International Heat Pipe Conference. May 19-24,2002,Moscow, Kostroma, Russia,vo12. F-2
[23] Satio Y, Mochizuki M, goto K, Nauyen T et al. The application for personal computer using heat pipe technology. 10th IHPC Preprints of Sessions e6 Stuttgart Sep.21～25,1997
[24] 林唯耕，陈绍文．微小化毛细泵吸环路(miniature CPL)应用于笔记本计算机传热之研究．工程热物理学报，Vol23．NO．5，Sep2002
[25] C S Chang, B J Huang,Yuri F Maidanik. Feasibility Study of a Mini LHP for CPU Cooling of a Notebook PC. 12th International Heat Pipe Conference, May 19-24,2002,Moscow, Kostroma,Russia, vo12.F-5
[26] Huang B J. " A network heat pipe for remote heat transport", 12th International Heat Pipe Conference, May 19-24,2002,Moscow, Russia, vo12.F-3
[27] Thang Nguyen, Masataka Mochizuki, et al. Advanced Cooling System Using Miniature Heat Pipes in Mobile PC. IEEE TRANSACTIONS ON COMPONENTS TECHNOLOGY, 23 (1)(2000) pp86-90
[28] Murakami M, Ogushi T, Sakurai Y, Masunoto H, Furukawa M, Imai R. Heat pipe heat sink, in:Proc.6th International Heat Pipe Conference,Grenoble,France, 1987,pp257-261
[29] Peterson G P. Duncan A B, Ahmed A S, Malik A K, Weichold M H. Experimental investigation of micro heat pipes in silcon wafers. Micromechanical Sensors. Actuators and Systems ASME-DEC 32(1991) pp341-348
[30] Peterson G P, Duncan A B. Experimental investigation of micro heat pipes fabricated in silcon wafers. J.Heat Trans, -T ASME 115(8) (1993) 751-576
[31] Peterson G P, Malik A K. Transient response characteristics of vapor deposited micro heat pipe arrays. J.Electron. Pack. 117(3) (1995) 82-87
[32] Malik A K, Peterson G P, Steady-state investigation of vapor deposited micro eat pipe arrays. J.Electron. Pack. 117(3) (1995)75-81
[33] Malik A K, Peterson G P, Weichold M H. On the use of micro heat pipes as an integral part of semi-conductor devices. J.Electron. Pack. 114(4) (1992) 436-442
[34] Khrustalev D, Faghri A. Thermal analysis of a micro heat pipe. J.Heat Trans-T.ASME 116(2)(1994) 189-198
[35] Dr. Altman E I, Mrs.Mukminova M Ia, The Loop Heat Pipe Evaporators theoretical analysis. 12th International Heat Pipe Conference, May 19-24,2002,Moscow, Kostroma,Russia, voll .A2-8
[36] Zhuang Jun. Research on CPU Heat Pipe Coolers, 12th International Heat PipeConference, May 19-24,2002,Moscow, Kostroma, Russia, vo12.F-6
[37] 廖光亚，江村．三维外肋重力热管散热器的实验研究．第八届全国热管会议论文集(成都，2002年7月)
[38] 吴存真，刘光铎合编．《热管在热能工程中的应用》．水利电力出版社，1993
[39] 陶文铨著．计算传热学的近代发展．科学出版社，2001
[40] 陶文铨，数值传热学．西安：西安交通大学出版社，1988．70-72，444，442
[41] Versteeg H K, Malalasekera W. An introduction to computational fluid dynamics. The finite volume method. Essex: Longman Scientific & Technical, 1995.72
[42] M Shiraishi, K Kikuohi and T Yamanishi Inveatigation of Heat Transfer Characteristics of a Two-Phase Closed Thermosyphon.6th Int .Heat Pipe Conf. 1987.
[43] Imura H, Sasaguchi K, Kozaj H. Critical Heat Flux In A Two-Phase Thermosyphon, Int.J.Heat Mass Transfer 26, 8(1983),p1181