臺灣博碩士論文加值系統

習知的電子裝備主要係依靠被動式之熱交換器進行散熱，以避免溫度過高而引起損壞；如今因積體電路之功率密度不斷提高，傳統的被動式熱交換器受限於空間及重量的限制，將無法提供所需的冷卻功率。有鑒於此，本論文提出一種應用磁流動力學理以推動導電性冷媒之熱交換器，並經由相關的理論分析與實驗結果獲得驗證。基於理論分析方向，由假設之穩態、不可壓縮之完全發展層流條件下，推導出導電性流體於羅倫茲力作用下的統御方程式，進而使用有限差分法求數值近似解，定量化評估熱交換器之冷卻能力。另於實驗方向，進行磁流動力泵及其熱交換實驗裝置之設計製作，以驗證冷媒於羅倫茲力推動下的流動速率及其所產生的總冷卻容量，由實驗結果得知，當外加磁通密度為0.41特士拉及外加電流為3安培時，所測得之流速為1.09×10-1 米/秒；經進一步分析實驗數據後得知，此熱交換器能夠以1微瓦特之輸入電功率，輸出約1瓦特之等效冷卻功率。故由本論文之理論分析與實驗驗證得知，應用磁流動力學理之熱交換器具有高效率之節能優勢，對於高發熱量之電子產品散熱相關應用具有極佳之發展潛力。

Electronic devices have been mainly relying on passive heat exchangers to transfer heat away for preventing catastrophic thermal problems in the past. Nowadays, passive heat exchangers no longer provide ample cooling efforts due to stringent spatial limitations of high power-density systems. In this dissertation, a novel heat exchanger system, based upon magneto-hydrodynamic theory for pumping electrically conducting coolant, has been studied and experimentally verified in details. Governing equations of electrically conducting fluid driven by the Lorentz forces were first derived by assuming steady state, incompressible and fully developed laminar flow conditions. Then, numerical simulations were conducted via the explicit finite-difference method to evaluate the performance of the heat exchanger. Finally, an experimental apparatus was built for measuring the coolant flow-velocity and the total cooling capacity. Nominal flow velocity of 1.09×10-1 m/s at 3 Ampere of electric current was observed while the magnetic flux density was maintained at 0.41 Tesla. The experimental results concluded that the heat exchanger could provide equivalent cooling power of 1 Watt per 1 micro Watt of input electric power; hence, this high efficiency magneto-hydrodynamic cooling system is very promising for the cooling applications in future power electronic products.

摘 要
ABSTRACT
ACKNOWLEDGEMENT
TABLE OF CONTENTS Ⅰ
LIST OF TABLES AND FIGURES Ⅲ
NOMENCLATURES AND NOTATIONS Ⅹ
CHAPTER 1 INTRODUCTION 1
1.1 Challenges of Electronic Cooling 1
1.2 Problem Statement 3
1.3 Scope of Study 6
CHAPTER 2 LITERATURE REVIEWS 9
2.1 Cooling Techniques for Electronic Equipment 9
2.1.1 Passive Cooling Techniques 10
2.1.2 Active Cooling Techniques 11
2.2 MHD Engineering Applications 16
2.2.1 Electromagnetic Processing of Molten Metals 17
2.2.2 MHD Micro-pumps 22
2.2.3 Heat Removal Applications 24
2.3 MHD Theoretical Analysis 25
2.4 Concluding Remarks 29
CHAPTER 3 MHD CHANNEL FLOW ANALYSIS 37
3.1 Fundamentals of Electromagnetic Theory 37
3.2 One-dimensional MHD Flow Analysis 39
3.2.1 Inviscid Flow with Incompressibility 39
3.2.2 Viscous Flow with Incompressibility 41
3.2.3 Equivalent Circuit Models 46
3.3 Two-dimensional MHD Flow Analysis 53
3.4 Simulation Results and Discussions 56
3.4.1 Flow Rate Predictions 56
3.4.2 Effects of Channel Geometry 58
3.4.3 Experimental Verifications 59
CHAPTER 4 ELECTROMAGNETIC ANALYSIS 73
4.1 Introduction of CAE Systems 73
4.2 MHD Pump Design 76
4.3 Analysis of Magnetostatic Field 80
4.4 Analysis of Electrostatic Field 82
CHAPTER 5 EXPERIMENTAL VERIFICATIONS 99
5.1 Experimental Setups 99
5.1.1 Hydrostatic Measurement 100
5.1.2 MHD Pump Measurement 101
5.1.3 Heat Exchanger Measurement 103
5.2 Results and Discussions 105
5.2.1 Flow Velocity Measurements 106
5.2.2 Pump Efficiency Determination 107
5.2.3 Cooling Measurements 110
CHAPTER 6 CONCLUSIONS AND FUTURE WORKS 123
6.1 Conclusions 124
6.2 Future Works 125
BIBLIOGRAPHY 127
APPENDIX A 132

BIBLIOGRAPHY

Asai, S., 1988 "Metallurgical Aspects of Electromagnetic Processing of Materials," Liquid Metal Magneto-hydrodynamics, Kluwer Academic Publishers, Boston, M. A., pp.391-400.

Asai, S., 1989, “Birth and Recent Activities of Electromagnetic Processing of Materials,” ISIJ International, Vol. 29, No. 12, pp. 981-992.

Baker, R. S. and Tessier, M. J., 1987, Handbook of Electromagnetic Pump Technology, Elsevier Science Ltd., New York, N. Y., pp. 1-32.

Barkan, P., Kelley, Jr., F. W. and Shook, T. A., 1974, “Increasing the Initial Flow Rate in a Rectifier Assembly Employing Electromagnetically-pumped Liquid Metal for Cooling,” U.S. Patent No. 3,812,404.

Bart, S. F., Tavrow, L. S. and Mehregany, M., 1990, “Microfabricated Electro- hydrodynamic Pumps,” Sensors and Actuators, A21-A23, pp. 193-197.

Bergles, A. E., 1990, Heat Transfer in Electronic and Microelectronic Equipment, Hemisphere Publishing Corporation, New York, N. Y., pp, 3-60.

Chu, R. C., 2003, “The Challenges of Electronic Cooling: Past, Current and Future,” IMECE2003-42198, Proceedings of IMECE’03, 2003 ASME International Mechanical Engineering Congress, Nov. 15-21, Washington, D.C., USA.

Fox, R. W. and McDonald, A. T., 1994, Introduction to Fluid Mechanics, John Wiley and Sons, Inc., 4th Ed., New York, N.Y., pp. 304-387.

Garnier, M., 1990, “Electromagnetic Processing of Liquid Materials in Europe,” ISIJ International, Vol. 30, No. 1, pp. 1-7.

Hamilton, R. E., Kennedy, P. G. and Vale, C. R., 1998, “Non-mechanical Magnetic Pump for Liquid Cooling,” U.S. Patent No. 5,763,951.

Heng, K. H., Huang, L., Wang, W. and Murphy, M. C., 1999, “Development of a Diffuser/Nozzle Type Micropump Based on Magnetohydrodynamic (MHD) Principle,” Proceedings of SPIE – Microfluidic Devices and Systems II, Vol. 3877, pp. 66-73.

Heng, K. H., Wang, W., Murphy, M. C. and Lian, K., 2000, “UV-LIGA Microfabrication and Test of an AC-Type Micropump Based on the Magnetohydrodynamic (MHD) Principle,” Proceedings of SPIE – Microfluidic Devices and Systems III, Vol. 4177, pp. 174-184.

Holroyd, R. J. and Walker, J. S., 1978, “A Theoretical Study of the Effects of Wall Conductivity, Non-uniform Magnetic Fields and Variable-area Ducts on Liquid Metal Flows at High Hartmann Number,” Journal of Fluid Mechanics, Vol. 84, pp. 471-495.

Huang, L., Wang, W. and Murphy, M. C., 1999, “A Lumped-Parameter Model for a Micropump Based on the Magnetohydrodynamic (MHD) Principle,” Proceedings of SPIE – Design, Test and Microfabrication of MEMS and MOEMS, Vol. 3680, pp. 379-387.

Huang, L., Wang, W., Murphy, M. C., Lian, K. and Ling, Z. G., 2000, “LIGA Fabrication and Test of a DC Type Magneto-hydrodynamic (MHD) Micropump,” Microsystem Technologies, Vol. 6, pp. 235-240.

Hughes, M., Pericleous, K. A. and Cross, M., 1994, “The CFD Analysis of Simple Parabolic and Elliptic MHD Flows,” Applied Mathematical Modelling, Vol. 18, pp. 150-155.

Hughes, M., Pericleous, K. A. and Cross, M., 1995, “The Numerical Modeling of DC Electromagnetic Pump and Brake Flow,” Applied Mathematical Modelling, Vol. 19, Dec., pp. 713-723.

Hughes, W. F. and Young, F. J., 1966, The Electromagnetodynamics of Fluids, John Wiley & Sons, Inc., New York, N. Y., pp. 167-298.

Hunt, J. C. R. and Ludford, G. S. S., 1968, “Three-dimensional MHD Duct Flows with Strong Transverse Magnetic Fields. Part 1. Obstacles in a Constant Area Channel,” Journal of Fluid Mechanics, Vol. 33, pp. 693-714.

Jackson, J. D., 1962, Classical Electrodynamics, John Wiley and Sons, Inc., New York, N. Y., pp. 469-479.

Jang, J. and Lee, S. S., 2000, “Theoretical and Experimental Study of MHD Micropump,” Sensors and Actuators, A80, pp. 84-89.

Jeong, O. C., and Yang, S. S., 2000, “Fabrication and Test of a Thermo-pneumatic Micropump with a Corrugated p+ Diaphragm,” Sensors and Actuators A83, pp.249-255.

Jon Zuo, Z., North, M. T., and Wert, K. L., 2001, “High Heat Flux Heat Pipe Mechanism for Cooling of Electronics,” IEEE Transactions on Components and Packaging Technologies, Vol. 24, No. 2, pp. 220-225.

Krasu, A. D. and Bar-Cohen, A., 1983, Thermal Analysis and Control of Electronic Equipment, Hemisphere Publishing Corp., Washington, pp. 303-480.

Lemoff, A. V. and Lee, A. P., 2000, “An AC Magnetohydrodynamic Micropump,” Sensors and Actuators, B63, pp. 178-185.

Lillicrap, D. C., 1988, “Liquid Metal Flow Control Using AC Fields,” Liquid Metal Magneto-hydrodynamics, Kluwer Academic Publishers, Boston, M. A., pp. 363-370.

Maillefer, D., Van Lintel, H., Rey-Mermet, G., and Hirschi, R., 1999, “A High-performance Silicon Micropump for an Implantable Drug Delivery System,” Proceeding of IEEE MEMS Workshop, pp. 541-546.

Manz, A., Effenhauser, C. S., Burggraf, N., Harrison, D. J., Seiler, K., and Flurri, K., 1994, “Electro-osmotic Pumping and Electrophoretic Separations for Miniaturized Chemical Analysis Systems,” Journal of Micromechanics and Microengineering 4, pp. 257-265.

McBride, S. E., Moroney, R. M., and Chiang, W., 1998, “Electro-hydrodynamic Pumps for High-density Microfluidic Arrays,” Proceedings of Micro Total Analysis Systems Conference, Oct. 13-16, pp. 45-48.

Nguyen, N. T., Schubert, S., Richter, S., and Dotzel, W., 1998, “Hybrid-assembled Micro Dosing System Using Silicon-based Micropump/valve and Mass Flow Sensor,” Sensors and Actuators A69, pp.85-91.

Olsson, A., Enoksson, P., Stemme, G. and Stemme, E., 1997, “Micromachined Flat-Walled Valve-less Diffuser Pumps,” Journal of Microelectromechanical Systems , Vol. 6, No. 2, pp.161-166.

Olsson, A., Stemme, G. and Stemme, E., 1995, “A Valve-less Planar Fluid Pump with Two Pump Chambers,” Sensors and Actuators, A46-A47, pp.549-556.

Ramos, J. I. and Winowich, N. S., 1986, “Magnetohydrodynamic Channel Flow Study,” Physics of Fluids, Vol. 29(4), April, pp. 992-997.

Ramos, J. I. and Winowich, N. S., 1990, “Finite Difference and Finite Element Methods for MHD Channel Flows,” International Journal for Numerical Methods in Fluids, Vol.11, pp. 907-934.

Rapp, R., Schomburg, W. K., Mass, D., Schulz, J., and Stark, W., 1994, “LIGA Micropump for Gases and Liquids,” Sensors and Actuators A40, pp.57-61.

Seraphim, D. P., Lasky, R. C., and Li, C. Y., 1993, Principles of Electronic Packaging, McGraw-Hill, Inc., New York, N. Y., pp.127-156.

Sergent, J. and Krum, A., 1998, Thermal Management Handbook, McGraw-Hill, Inc., New York, N. Y., pp. 7.1-7.59.

Stemme, E. and Stemme, G., 1993, “A Valve-less Diffuser/Nozzle-based Fluid Pump,” Sensors and Actuators, A39, pp.159-167.

Szekely, J. and Chang, C. W., 1976, “Electro-magnetically Driven Flows in Metals Processing,” Journal of the Minerals, Metals and Materials Society, Sept., pp. 6-11.

Walker, J. S. and Ludford, G. S. S, 1972, “Three-dimensional MHD Duct Flows with Strong Transverse Magnetic Fields. Part 4. Fully Insulated, Variable-area Rectangular Ducts with Small Divergences,” Journal of Fluid Mechanics, Vol. 56, pp. 481-496.

Walker, J. S., Ludford, G. S. S. and Hunt, J. C. R., 1971, “Three-dimensional MHD Duct Flows with Strong Transverse Magnetic Fields. Part 2. Variable-area Rectangular Ducts with Conducting Sides,” Journal of Fluid Mechanics, Vol. 46, pp. 657-684.

Walker, J. S., Ludford, G. S. S. and Hunt, J. C. R., 1972, “Three-dimensional MHD Duct Flows with Strong Transverse Magnetic Fields. Part 3. Variable-area Rectangular Ducts with Insulating Walls,” Journal of Fluid Mechanics, Vol. 56, pp.121-141.

Webb, R. L., 2003, “Next Generation Devices for Electronic Cooling,” IMECE2003-42179, Proceedings of IMECE’03, 2003 ASME International Mechanical Engineering Congress, Nov. 15-21, Washington, D.C., USA.

Wiech, Jr., R. E., 1985, “Substrate Cooling,” U.S. Patent No. 4,519,447.

Yang, Y. S., Liu, Q. M., Jiao, Y., Ge, Y. L., Hu, Z. Q., Gao, Y. Y., Jia, G. L. and Zhang, J. S., 1995, “Application of Steady Magnetic Field for Refining Solidification Structure and Enhancing Mechanical Properties of 25Cr-20Ni-Fe-C Alloy in Centrifugal Casting,” ISIJ International, Vol. 35, No. 4, pp. 389-392.

Zengerle, R., Ulrich, J., Kluge, S., Richter, M., and Richter, A., 1995, “A Bi-directional Silicon Micropump,” Sensors and Actuators, A50, pp.81-86.

Zhang, W. Q., Yang, Y. S., Zhu, Y. F., Liu, Q. M. and Hu, Z. Q., 1998, “Structural Transition and Macro-segregation of Al-Cu Eutectic Alloy Solidified in the Electromagnetic Centrifugal Casting Process,” Metallurgical and Materials Transactions A, Vol. 29A, Jan., pp. 404-408.

Zhou, P., Hom, J., Upadhya, G., Goodson, K. and Mouch, M., 2004, “Electro-kinetic Microchannel Cooling System for Desktop Computers,” Semiconductor Thermal Measurement and Management, 2004 IEEE Twentieth Annual IEEE (SEMI THERM) Symposium, Mar. 9-11, pp.26-29.