顏家鈺陳炳煇臺灣大學：李亞偉Lee, Ya-WeiYa-WeiLee2007-11-282018-06-282007-11-282018-06-282006http://ntur.lib.ntu.edu.tw//handle/246246/60945無Among the novel electronic cooling devices, miniature heat pipes (MHP) have been received attention in recent years. For understanding the thermal mechanism of MHPs completely, two types of MHPs have been investigated in this dissertation. One is a disk-shaped miniature heat pipe (DMHP) and the other is a multi-loop pulsating heat pipe (MLPHP). A mounting base integrated with DMHP is designed for laser diode TO can package. For understanding the temperature distribution and physical phenomenon of DMHP, a CFD model is made using the commercial code, Fluent 6.1.18. Combining the applications of this package and user defined C++ program, two-phase heat/mass transfer mechanism is built. The modeling results and the experimental data are reported and are in good agreement with each other. Mathematical modeling of the MLPHP is a contemporary problem that remains quite elusive. Simplifications and assumptions made in all the modeling approaches developed so far render them unsuitable for engineering design. In this dissertation, a more realistic modeling scheme is presented which proves considerable information for thought toward the next progressive step. At different operational conditions, the MLPHP experience bulk internal flow circulations. A time average model based on design parameters for predicting thermal performance has been developed, and from which the optimal suggestions could be provided. In addition, the non-linear auto-regressive moving average model with exogenous inputs (NARMAX) approach is employed to analyze the dynamics of the MLPHP. The nonlinearity would be represented in both time and frequency domains. High speed flow visualization for the MLPHP is provided. It is identified that there exists the bulk circulation flow that lasts longer and the local flow direction switch flow. Dispersed bubbles, vapor plugs and the transition flow patterns from the dispersed bubbles to the vapor plugs are the major flow patterns in the MLPHP. By increasing the heating power, vapor plugs observed became shorter and more uniformly dispersed due to the vapor plug deformation and breakup mechanism. Bubble sizes have unsymmetrical distributions among various tubes. The complex combined effects of bubble nucleation, coalescence and condensation are responsible for the oscillation flow in the MLPHP. From analyzing the effect of operational parameters on thermal performance of MLPHP, the vertical bottom heating mode is regarded as the optimal operational condition. In addition, a comprehensive description of the effect for each combination of conditions (charge ratio, heating power, heating mode, orientation) is provided by experiment.Contents Acknowledgement I Abstract III Contents VI List of Tables XI List of Figures XIV Nomenclature XXII Chapter 1 : Introduction 1 1.1 General Remarks 1 1.2 Historical Development of Heat Pipe 3 1.3 Limitations in Heat Pipe 7 1.4 Motivation and Applied Method 7 1.4.1 Construction of Heat/Mass Transfer Model to Analysis Two-Phase Flow 8 1.4.2 Multiple Analysis of MLPHP for Revealing Operational Mechanism and System Dynamics 10 1.4.3 Confirmation of the Predicted Dynamic Behaviors of MLPHP with Visualizations of Flow Patterns at Different Operational Conditions 11 1.4.4 Effect of Operational Parameters on Thermal Performance of the MLPHP 12 1.5 Present Study 13 1.6 Dissertation Organization 14 Chapter 2: Numerical Simulation of Conjugate Heat Transfer in a Disk-Shaped Miniature Heat Pipe 16 2.1 Motivation 16 2.2 Description of DMHP 19 2.3 CFD Simulation of DMHP 21 2.4 Results and Discussion 27 2.5 Summary 33 Chapter 3 : Various Analyses of Multi-Loop Pulsating Heat Pipe 34 3.1 Working Principle of Pulsating Heat Pipe (PHP) 34 3.2 Thermal Oscillation of PHP 37 3.3 Time Average Analysis of MLPHP 40 3.3.1 Experimental Setup 40 3.3.2 Establishment of Prediction Models 43 3.3.3 Experimental Results and Optimal Design Suggestions 48 3.4 Application of Power Spectral Density (PSD) Approach in Thermal Instability Analysis 53 3.4.1 PSD Analysis of LHP 55 3.4.2 PSD Analysis of MLPHP 57 3.4.2.1 Low Heating Power Condition (30W) 57 3.4.2.2 High Heating Power Condition (110W) 59 3.5 Time and Frequency Domain Identification of Two-Phase Flow Motion in MLPHP 61 3.5.1 NARMAX Approach 61 3.5.2 Analysis and Interpretation of Higher-order Generalized Frequency Response Functions (GFRF) of a Nonlinear System 64 3.6 System Description and Modeling Strategies 69 3.7 Time Domain Analysis of MLPHP 71 3.7.1 Low Charge Ratio Condition (20%) 71 3.7.2 Medium Charge Ratio Condition (60%) 72 3.7.3 High Charge Ratio Condition (90%) 73 3.8 Frequency Domain Analysis of MLPHP 74 3.8.1 Low Charge Ratio Condition (20%) 75 3.8.2 Medium Charge Ratio Condition (60%) 76 3.8.3 High Charge Ratio Condition (90%) 77 3.9 Energy Transfer along the cooling section of MLPHP 78 Chapter 4: Flow Visualization of Two-Phase Flow in MLPHP 81 4.1 Dominant Flow Patterns in MLPHP 82 4.1.1 Bubbly flow 82 4.1.2 Slug flow 83 4.1.3 Mist flow 83 4.2 Correlations of Flow Pattern Transition 84 4.3 Experimental Setup 87 4.4 Analysis of Long Duration Observations 89 4.4.1 Low Heating Power Conditions (30W) 90 4.4.2 Medium Heating Power Conditions (70W) 92 4.4.3 High Heating Power Conditions (110W) 93 4.5 The Momentary Transitions of Flow Patterns 94 4.6 Summary 96 Chapter 5: Effects of Operational Parameters on Thermal Performance of MLPHP 100 5.1 Experimental Procedure 100 5.2 Effect of Orientation Angle 102 5.3 Effect of Heating Mode 103 5.4 Effect of Charge Ratio 104 5.5 Normal Operational Possibility of MLPHP at Different Orientation 106 5.6 Summary 108 Chapter 6: Conclusions and Future Prospects 110 References 247 Appendix 25718948489 bytesapplication/pdfen-US多迴路脈衝熱管兩相流能量頻譜密度非線性系統識別multi-loop pulsating heat pipetwo-phase flow oscillationNARMAXpower spectral densitythesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/60945/1/ntu-95-D91522007-1.pdf