臺灣博碩士論文加值系統

本文搭配實驗與數值分析，研究中央處理器(Central Processing Unit)之相關散熱系統。CPU係個人電腦運跑中，執行指令與運算上必需的微處理器，隨著運算速度加快、尺寸越來越小，其單位面積的熱量變大，易造成處理器可靠度降低、使用之壽命縮短，因此現今對CPU之熱管理相關研究已日漸被重視。
許多散熱系統係用於帶走CPU所產生之熱量；其中一個增進散熱的方法，係利用風扇散熱器以增加散熱的效能。散熱鰭片易於製造，成本也相對較低，且重量輕，可成為一個合乎產業界需求的冷卻方式，並具有良好的可靠度。
於本研究中，藉功率為95瓦的CPU (Pentium D082 2.8GHz) 作為熱源，以研究風扇散熱器的效率。效率係衡量CPU與散熱器之間的熱阻值，其較高的散熱能力將具較低之熱阻值。實驗中，將研究散熱鰭片的材料性質、鰭片的形狀與數量對於熱阻值的效果。從自本研究結果顯示，散熱鰭片的熱阻值最主要是由散熱器的材料性質與散熱鰭片的形狀而定。
此外，散熱片的材料性質也是本研究的一部分。主要有下列三種材質：蒸氣胺(vapor chamber)，銅塊及鋁塊。結果顯示，蒸氣胺被證明是最有效的散熱材質。添加蒸氣胺與使用其他類型的散熱片比較起來是增加最多的散熱性能，且有最低的熱阻值。
數值分析軟體部分使用ANSYS-ICEPAK 12.1，此軟體內置可視化系統之溫度分佈便於與實驗進行比對，亦被證明係適合電子散熱系統分析之模擬軟件。研究顯示，實驗數據與模擬結果甚為吻合，誤差小於10%。

The Central Processing Unit (CPU) is the microprocessor within a personal computer that performs all instructions and operations necessary for the computer to function. Higher speed and smaller size in computer processors have resulted in an increased demand for thermal management systems. When driven at high clock speeds, they are capable of producing substantial amounts of heat and need to be cooled to prevent failure. Many cooling system is used to dissipate heat from CPU. One of the CPU’s heat dissipation methods is using fan heat sink. Heat sink is easily to be manufactured, relatively low in cost, light in weight, and can become an adequate cooling means with good reliability
In this study, 95-W of CPU Pentium D082 2.8GHz was used as a heat source for studying the effectiveness of fan heat sink. The effectiveness was measured by the thermal resistance value between the CPU and the heat sink. Lower thermal resistance value is needed for higher heat dissipation capability.
Through the experiments, the effects of heat sink material, number of fin, fin shape, and fin complexity on the thermal resistance values of the CPU were investigated. From this study it was shown that the thermal resistance was dominantly influenced by the heat sink material, followed by the heat sink fin type.
Moreover, the effect of heat spreader to the heat sink resistance value was also investigated. Three types of heat spreader used in this study were aluminum block, copper block, and vapor chamber. Each of these heat spreaders was inserted between the CPU and fan heat sink. The results showed that vapor chamber is proven to be the most efficient heat spreader. Adding vapor chamber would increase the heat sink heat dissipation performance, measured by having the lowest thermal resistance value compared with using other types of heat spreaders.
Numerical simulations of ANSYS ICEPAK 12.1 were used to analyze CPU and fan heat sink heat dissipation and to visualize the temperature distribution of the system. It was found that the results obtained from numerical simulations were in good agreement with those obtained from the experimental data, with a percentage difference of less than or equal to 10%. ANSYS ICEPAK 12.1 was also proven to be suitable software for electronics cooling simulations.

Contents

摘要………………………………………………………………………………………. I
Abstract.………………………………………………………………………………….. II
Acknowledgments……………………………………………………………………….. III
Contents………………………………………………………………………………….. IV
List of Figures……………………………………………………………………………. VI
List of Tables……………………………………………………………………………... X

Chapter 1 Introduction
1.1 Motivation………………………………………………………………………… 1
1.2 Literature Review.………………………………………………………………… 3
1.2.1 Thermal Management of CPU.……………………………………………. 3
1.2.2 Vapor Chamber Heat Dissipation System……………………………….... 4
1.3 About this study…………………………………………………………………… 6
1.3.1 Problem Statement and Scope........................................................................ 6
1.3.2 Organization of Thesis…………………………………………………….. 6

Chapter 2 Experimental Setup and Procedures
2.1 Experimental Setup……………………………………………………………….. . 8
2.1.1 Test Samples …………………………………………………………….... 8
2.1.2 Test Facilities …………………………………………………………….. 11
2.2 Procedures ………………………………………………………………………... 13
2.2.1 Temperature Measurement ……………………………………………….. 13
2.2.2 Uncertainty Analysis ……………………………………………………... 14

Chapter 3 Numerical Simulation
3.1 Mathematical Model ……………………………………………………………… 15
3.2 Numerical Simulation …………………………………………………………….. 17

Chapter 4 Results and Discussion
4.1 Fan Heat Sink without Heat Spreader……………………………………………... 23
4.1.1 CPU Heat Dissipation System Using First Heat Sink………………………. 24
4.1.2 CPU Heat Dissipation System Using Second Heat Sink…………………… 28
4.1.3 CPU Heat Dissipation System Using Third Heat Sink……………………... 32
4.2 CPU Heat Dissipation System using Heat Spreader and Fan Heat Sink ………… 36
4.2.1 CPU with Aluminum Block and Aluminum-Copper Crotch Fin Heat Sink.. 37
4.2.2 CPU with Copper Block and Aluminum-Copper Crotch Fin Heat Sink…… 41
4.2.3 CPU with Vapor chamber and Aluminum-Copper Crotch Fin Heat Sink…. 45
4.2.4 CPU with Aluminum Block and Aluminum Crotch Fin Heat Sink………... 49
4.2.5 CPU with Copper Block and Aluminum Crotch Fin Heat Sink……………. 53
4.2.6 CPU with Vapor Chamber and Aluminum Crotch Fin Heat Sink………….. 57
4.2.7 CPU with Aluminum Block and Aluminum Straight Fin Heat Sink……….. 61
4.2.8 CPU with Copper Block and Aluminum Straight Fin Heat Sink…………… 65
4.2.9 CPU with Vapor Chamber and Aluminum Straight Fin Heat Sink………… 69
Chapter 5 Conclusions and Recommendations for Future Work
5.1 Conclusions.………………………………………………………………………. 75
5.2 Recommendations for Future Work.……………………………………………… 76
References.…………………………………………………………………... 77
Resume.…………………………………………………………………….... 79

List of Figures

Figure 2.1 Experimental Setup ……………………………………………………...…... 8
Figure 2.2 Dimensions of Aluminum/Copper Block/ Vapor Chamber………….....…..... 9
Figure 2.3 Dimensions of Aluminum Circular Straight Fin Heat Sink…………...…….. 10
Figure 2.4 Dimensions of Aluminum/ Copper Crotch Fin Heat Sink……………....…... 10
Figure 2.5 CPU…………………………………………………………………….……. 10
Figure 2.6 Copper Block, Vapor Chamber and Aluminum Block..…………………….. 11
Figure 2.7 Aluminum and Copper Crotch Fin Heat Sink……………………………….. 11
Figure 2.8 Aluminum Circular Straight Fin Heat Sink………………………………….. 11
Figure 2.9 CPU Intel Pentium D082……………………………………………………. . 12
Figure 2.10 Intel Fan……………………………………………………………………... . 12
Figure 2.11 Experimental Apparatus: CPU Chamber and Thermocouples Reader………. 12
Figure 3.1 Principals of Thermal Resistance…………………………………….….…… 17
Figure 3.2 ANSYS ICEPAK 12.1 Program Structure……………………………….…... 17
Figure 3.3 ANSYS ICEPAK Basic Parameters and Settings……………………………. 19
Figure 3.4 ANSYS ICEPAK Mesh Control………………………………………...…… 20
Figure 3.5 ANSYS ICEPAK Hex-Dominant Mesh.………………………………..…… 20
Figure 3.6 ANSYS ICEPAK Solving Dialog Box …………..………………………..… 21
Figure 3.7 ANSYS ICEPAK Convergence Plot…............................................................. 22
Figure 4.1 Thermocouples Positions…….……………………………......…………….. . 23
Figure 4.2 Speed Fan Software…………………. ……………………………..……….. 26
Figure 4.3 CPU with First Heat Sink Experiment Temperature……………………....… 26
Figure 4.4 CPU and First Heat Sink Simulation…………………………...……….…… 27
Figure 4.5 First Heat Sink Temperature………………………………....…………......... 27
Figure 4.6 Convergence Plot of CPU with First Heat Sink Simulation……………........ . 28
Figure 4.7 CPU with Second Heat Sink Experiment Temperature …………………...… 30
Figure 4.8 CPU and Second Heat Sink Simulation ……………………………………... 30
Figure 4.9 Second Heat Sink Temperature ….……………………………....................... 31
Figure 4.10 Convergence Plot of CPU with Second Heat Sink Simulation …………….... 31
Figure 4.11 CPU with Third Heat Sink Experiment Temperature………………………... 34
Figure 4.12 CPU and Third Heat Sink Temperature……………………………….……... 34
Figure 4.13 Third Heat Sink Temperature….….……………………………....................... 35
Figure 4.14 Convergence Plot of CPU with Third Heat Sink Simulation………………… 35
Figure 4.15 Resistance Value of Heat Sink……………………………………………...... 36
Figure 4.16 Thermocouples position……………………………………………………… 37
Figure 4.17 CPU with Aluminum Block and First Heat Sink Experiment Temperatures… 39
Figure 4.18 CPU with Aluminum Block and First Heat Sink Temperature……..………... 39
Figure 4.19 Aluminum Block Temperature of CPU with Aluminum Block and
First Heat Sink Model……..…………………………………………………. 40
Figure 4.20 Heat Sink temperature of CPU with Aluminum Block and
First Heat Sink Model……..…………………………………………………. 40
Figure 4.21 Convergence Plot of CPU with Aluminum Block and
First Heat Sink Simulation…………………………………………………… 40
Figure 4.22 CPU with Copper Block and First Heat Sink Experiment Temperatures…….. 43
Figure 4.23 CPU with Copper Block and First Heat Sink Temperature……….………….. 43
Figure 4.24 Copper Block Temperature of CPU with Copper Block and
First Heat Sink Model……………………...………………………………... 44
Figure 4.25 Heat Sink temperature of CPU with Copper Block and
First Heat Sink Model………………………………………..………..……… 44
Figure 4.26 Convergence Plot of CPU with Copper Block and
First Heat Sink Simulation…………………………………………..……..... 44
Figure 4.27 CPU with Vapor Chamber and First Heat Sink Experiment Temperatures.…. 47
Figure 4.28 CPU with Vapor Chamber and First Heat Sink Temperature………………... 47
Figure 4.29 Vapor Chamber Temperature of CPU with Vapor Chamber and
First Heat Sink Model……..…………………………………………………. 48
Figure 4.30 Heat Sink temperature of CPU with Vapor Chamber and
First Heat Sink Model……..…………………………………………..……... 48
Figure 4.31 Convergence Plot CPU with Vapor Chamber and
First Heat Sink Simulation…………………………………………………... 48
Figure 4.32 CPU with Aluminum Block and Second Heat Sink Experiment
Temperatures………………………………………………………………… 51
Figure 4.33 CPU with Aluminum Block and Second Heat Sink Temperature..………….. 51
Figure 4.34 Aluminum Block Temperature of CPU with Aluminum Block and
Second Heat Sink Model……..………………………………………………. 52
Figure 4.35 Heat Sink temperature of CPU with Aluminum Block and
Second Heat Sink Model……..………………….…………………………… 52
Figure 4.36 Convergence Plot CPU with Aluminum Block and
Second Heat Sink Simulation……………………………………….……….. 52
Figure 4.37 CPU with Copper Block and Second Heat Sink Experiment
Temperatures………………………………………………………………… 55
Figure 4.38 CPU with Copper Block and Second Heat Sink Temperature……..………… 55
Figure 4.39 Copper Block Temperature of CPU with Copper Block and
Second Heat Sink Model……..………………………………………………. 56
Figure 4.40 Heat Sink temperature of CPU with Copper Block and
Second Heat Sink Model……..………………….…………………………… 56
Figure 4.41 Convergence Plot CPU with Copper Block and
Second Heat Sink Simulation………………………………………………... 56
Figure 4.42 CPU with Vapor Chamber and Second Heat Sink Experiment
Temperatures………………………………………………………………… 59
Figure 4.43 CPU with Vapor Chamber and Second Heat Sink Temperature……..……... . 59
Figure 4.44 Vapor Chamber Temperature of CPU with Vapor Chamber and
Second Heat Sink Model……..………………………………………………. 60
Figure 4.45 Heat Sink temperature of CPU with Vapor Chamber and
Second Heat Sink Model……..………………….…………………………… 60
Figure 4.46 Convergence Plot CPU with Vapor Chamber and
Second Heat Sink Simulation………………………………………………... 60
Figure 4.47 CPU with Aluminum Block and Third Heat Sink Experiment
Temperatures………………………………………………………………… 63
Figure 4.48 CPU with Aluminum Block and Third Heat Sink Temperature……..……..... 63
Figure 4.49 Aluminum Block Temperature of CPU with Aluminum Block and
Third Heat Sink Model……..………………………………………………… 64
Figure 4.50 Heat Sink temperature of CPU with Aluminum Block and
Third Heat Sink Model……..………………….…………………………...… 64
Figure 4.51 Convergence Plot CPU with Aluminum Block and
Third Heat Sink Simulation………………………………………………….. 64
Figure 4.52 CPU with Copper Block and Third Heat Sink Experiment
Temperatures………………………………………………………………… 67
Figure 4.53 CPU with Copper Block and Third Heat Sink Temperature…..……..……..... 67
Figure 4.54 Copper Block Temperature of CPU with Copper Block and
Third Heat Sink Model……..………………………………………………… 68
Figure 4.55 Heat Sink temperature of CPU with Copper Block and
Third Heat Sink Model……..………………….…………………………...… 68
Figure 4.56 Convergence Plot CPU with Copper Block and
Third Heat Sink Simulation………………………………………………….. 68
Figure 4.57 CPU with Vapor Chamber and Third Heat Sink Experiment
Temperatures………………………………………………………………… 71
Figure 4.58 CPU with Vapor Chamber and Third Heat Sink Temperature…..……..…….. 71
Figure 4.59 Vapor Chamber Temperature of CPU with Vapor Chamber and
Third Heat Sink Model……..………………………………………………… 72
Figure 4.60 Heat Sink temperature of CPU with Vapor Chamber and
Third Heat Sink Model……..………………….…………………………...… 72
Figure 4.61 Convergence Plot CPU with Vapor Chamber and
Third Heat Sink Simulation………………………………………………….. 72
Figure 4.62 Resistance Value for Heat Sink with Heat Spreader ………………………… 74

List of Tables

Table 2.1 Copper and Aluminum Material Properties…………………………………… 9
Table 2.2 Device Technical Data………………………………………………………... 9
Table 3.1 Typical Values of Dimensionless Parameters in Forced and Natural
Convection ………………………………………….......................................... 19
Table 4.1 Heat Sink Dimension………………………………………………………..… 23
Table 4.2 CPU with First Heat Sink Experiment Temperature Result
(T3=ambient temperature)…………………………..……………………….... 25
Table 4.3 Experiment and Numerical Simulation Results of CPU
with First Heat Sink……………………………………………………….…... 28
Table 4.4 CPU with Second Heat Sink Experiment Temperature Result
(T3=ambient temperature)………………………………………………..….... 29
Table 4.5 Experiment and Numerical Simulation Results of CPU
with Second Heat Sink……………………………………………………….. .. 31
Table 4.6 CPU with Third Heat Sink Experiment Temperature Result
(T3=ambient temperature)………………………………………………..….... 33
Table 4.7 Experiment and Numerical Simulation Results of CPU
with Third Heat Sink………………………………………………………….. 35
Table 4.8 CPU with Aluminum Block and First Heat Sink Experiment Temperature
Result (T4=ambient temperature)………………………………………..……. 38
Table 4.9 Experiment and Numerical Simulation Results of CPU
with Aluminum Block and First Heat Sink…………………………………… 41
Table 4.10 CPU with Copper Block and First Heat Sink Experiment Temperature
Result (T4=ambient temperature)………………………………………..…… 42
Table 4.11 Experiment and Numerical Simulation Results of CPU
with Copper Block and Aluminum-Copper Crotch Fin Heat Sink…………… 45
Table 4.12 CPU with Vapor Chamber and First Heat Sink Experiment Temperature
Result (T4=ambient temperature)………………………………………..…… 46
Table 4.13 Experiment and Numerical Simulation Results of CPU
with Vapor Chamber and Aluminum-Copper Crotch Fin Heat Sink………… 49
Table 4.14 CPU with Aluminum Block and Second Heat Sink Experiment Temperature
Result (T4=ambient temperature)…………………………………………….. 50
Table 4.15 Experiment and Numerical Simulation Results of CPU
with Aluminum Block and Aluminum Crotch Fin Heat Sink…..….………… 53
Table 4.16 CPU with Copper Block and Second Heat Sink Experiment Temperature
Result (T4=ambient temperature)…………………………………………….. 54
Table 4.17 Experiment and Numerical Simulation Results of CPU
with Copper Block and Aluminum Crotch Fin Heat Sink……………………. 57
Table 4.18 CPU with Vapor Chamber and Second Heat Sink Experiment Temperature
Result (T4=ambient temperature)…………………………………………….. 58
Table 4.19 Experiment and Numerical Simulation Results of CPU
with Vapor Chamber and Aluminum Crotch Fin Heat Sink…………………. 61
Table 4.20 CPU with Aluminum Block and Third Heat Sink Experiment Temperature
Result (T4=ambient temperature)…………………………………………….. 62
Table 4.21 Experiment and Numerical Simulation Results of CPU
with Aluminum Block and Aluminum Straight Fin Heat Sink………………. 65
Table 4.22 CPU with Copper Block and Third Heat Sink Experiment Temperature
Result (T4=ambient temperature)…………………………………………….. 66
Table 4.23 Experiment and Numerical Simulation Results of CPU
with Copper Block and Aluminum Straight Fin Heat Sink…………………... 69
Table 4.24 CPU with Vapor Block and Third Heat Sink Experiment Temperature
Result (T4=ambient temperature)…………………………………………….. 70
Table 4.25 Experiment and Numerical Simulation Results of CPU
with Vapor Chamber and Aluminum Straight Fin Heat Sink………………... 73
Table 4.26 Experiment and Simulation Results of Heat Sink with Heat Spreader……… 74

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