本研究主要目的在探討使用不同材質的奈米等級厚度鍍膜表面，增強迷你型壓電片噴嘴的噴霧冷卻系統之冷卻性能。薄膜表面的奈米等級粗糙度將會增加反應面積並使核沸騰時產生核沸騰氣泡的成核點增加，藉此增強噴霧冷卻的沸騰熱傳。實驗中以銅為測試表面基底，在其表面鍍上不同之材質薄膜石墨烯(graphene)、多壁奈米碳管(MCNT)和類鑽石碳(DLC)，並使用噴嘴孔徑35µm、質量流量 5.33×10^(-4) kg/s、噴霧高度50mm的多孔壓電霧化片噴嘴將工作流體DI water噴灑在加熱的測試表面上做噴霧冷卻實驗，並使用T-type熱電偶測量溫度，之後計算其測試表面溫度和熱傳量等相關參數，使用計算得到的相關參數繪製其沸騰曲線和淬火曲線，並分析薄膜粗糙表面對噴霧冷卻熱傳特性之影響。

The objective of this study was to investigate the effect of coated thin films (several nanometers thick) made from different materials on enhancing the cooling performance of a spray cooling system that contained a spray nozzle with a mini piezoelectric piece. The roughness of the thin film surfaces increased the reaction areas as well as the number of nucleation sites (which formed bubbles during nucleate boiling), improving the boiling heat transfer performance of the spray cooling system. For the study experiment, copper was used as the base of the test surfaces, which were coated with thin films made from different materials (i.e., graphene, multiwall carbon nanotubes (MCNT), and diamond-like carbon (DLC). Next, a porous piezoelectric spray nozzle with an atomization piece, an aperture of 35µm, a mass flow rate of 5.33×10^(-4)kg/s, and a spray height of 50 mm was used to spray DI water as a working fluid on heated test surfaces, initiating the spray cooling experiment. A T-type thermocouple was used to measure the resulting temperatures, after which related parameters such as test surface temperatures and heat transfer amounts were calculated. The related parameters were used to generate boiling and quench curves to analyze the effect of thin film surface roughness on the ability of spray cooling to improve heat transfer properties.

CONTENTS
Page
誌謝................................................................................................................i
中文摘要………………………………………………………………...........…...ii
ABSTRACT...…………………………………………………………….............iii
CONTETS..………………………………………………………………............iv
LIST OF TABLES…..………………………………………………….........…...v
LIST OF FIGURES…..…………………………………………….........……...vii
NOMENCLATURE……………………………………………………..........…..x

CHAPTER 1 INTRODUCTION..……………………………………….......….1
1-1 Indroduction..……………………………………………………...............1
1-2 Background…………………………………………………..............…...2
1-3 Literature review…………………………………………..…............…...5
1-4 Research Objective….……………………………………….............…22
CHAPTER 2EXPERIMENT SYSTEM AND EQUIPMENT………….........23
2-1 Piezoelectric atomization..……………………………………..............23
2-2 Heating test device.…………………………………………….............23
2-3 Temperature measurement recording instrnments.………....……....24
2-4 AC power control system...…………………………………........…....24
2-5 Tool microscope.……………………………………………….............25
2-6 SEM……………………………………………………………..............25
2-7 AFM……………………………………………………...……...............26
CHAPTER 3EXPERIMENTAL METHODSAND PROCEDURES.……..32
3-1 Test surfacepreparation………………………………………............32
3-2 Experimental method..………………………………..……….............33
3-3 Aataanlysis…………...………………………………………...............34
CHAPTER 4 THEORETICAL ANALTSIS…………………………...…....40
4-1 The definition of Weber number(We)………………………..............40
4-2 The definition of Sauter mean diameter (SMD,d32)…………..........40
4-3 The definition of Reynolds number (Re)…………………….............41
4-4 Calculation of Heat flux (q") ……………………………….................42
4-5 Calculation of the surface temperature (TW)………………............ 43
4-6 Calculation of the heat transfer coefficient (HTC,h)………..............43
CHAPTER 5 UNCERTAINITY ANALYSIS………………………….........44
CHAPTER 6 RESULTSAND DISCUSSIONS………………………..…..49
6-1 Quench………………………………………………………................49
6-1-1 Quench curve of smooth copper surface…………………............49
6-1-2 Quench curve of nanotextured surface…………………...............50
6-1-3 h-t curve of smooth copper surface and nanotexured surface….55
6-2 Boiling curve………………………………………………………........55
6-2-1 Steady-state boiling curve……………………………………....…..55
6-2-2 HTC vs.ΔT curve……………………………………………......…...57
6-3 q"-h correlation of graphene surface……………………………..….58
6-4 Steady state and transient boiling curve………………………….....58
6-5 Nanotextured surface heat transfer effect enhancement……….....59
CHAPTER7CONCLUSION AND RECOMMENDATIONS………….....84
7-1 Conclusion……………………………………………………….........84
7-2 Recommendations and suggestions………………………………..85
REFERENCE………………………………………………………..….....86
APPENDIX A…………………………………………………………........91
 
LIST OF TABLES
Table 2-1 Parameters of nozzle….………………………………………..27
Table 3-1 Relevant parameters of typical nano-texted surface for three different materials...…35
Table3-2 Deionized water properties(DI water @ 25oC, 1 atm)……….....36
Table 3-3 Experimental parameters and variables of the study.…………..37
Table 5-1Measurement uncertainty for relevant parameters..…………….48
Table 6-1 Boiling curve parameter for smooth and nano-texted surface…61

LIST OF FIGURES
Fig.2-1 (a) PZT ultrasonic nozzle plate (b)SEMimage of PZT nozzle…...28
Fig.2-2 Heater……………………………………………………………........29
Fig.2-3 (a) NI9213 (b) Power supply(c)Tool microscope………………....30
Fig.2-4 (a) SEM (b) AFM………………………………………………......…31
Fig. 3-1 AFM image for four different surfaces with the associated morphology (a) polished copper (b) DLC (c)MCNT (d)graphene…..38
Fig.3-2Schematic of the experimental flow loop……………………...……39
Fig. 6-1 Quench curve of polished copper……………………………..…..62
Fig. 6-2 Quench curve of polished copper 0~450s………………………..63
Fig. 6-3 Quench curve of DLC surface (700 nm, 1000 nm)……………...64
Fig. 6-4 (a) Quench curve of DLC 700nm surface 0~200s (b) Quench curve of DLC 1000nm surface 0~450s………...65
Fig. 6-5 Quench curve of MCNT surface (50 nm, 100 nm,150 nm)……...66
Fig. 6-6 (a) Quench curve of MCNT 50 nm surface 0~300s (b) Quench curve of MCNT 100 nm surface 0~300s (c) Quench curve of MCNT 150 nm surface0~300s……………67
Fig. 6-7 Quench curve ofgraphene surface (1 nm, 2 nm,5 nm,10 nm)…...68
Fig. 6-8 (a) Quench curve ofgraphene 1 nm surface 0~150s (b) Quench curve ofofgraphene 2 nm surface 0~150s (c) Quench curve of ofgraphene 5 nm surface 0~250s (d) Quench curve of ofgraphene 10 nm surface 0~250s…………...69
Fig. 6-9 Transient h-t curve (a) polished copper (b) DLC………………...70
Fig. 6-10 Transient h-t curve (a) MCNT (b)graphene…………………….71
Fig. 6-11 Steady boiling curve of polished copper………………………..72
Fig. 6-12 Steady boiling curve (a) DLC (b)MCNT…………………….…73
Fig. 6-13 Steady boiling curve (a) graphene (b)all……………………….74
Fig. 6-14 HTC vs.ΔT curve (a) polished copper (b) DLC…..…………...75
Fig. 6-15 HTC vs.ΔT curve (a) MCNT (b) graphene……………………76
Fig. 6-16 h-q"correlation for graphene…………………………………...77
Fig. 6-17 Steady and transient boiling curve (a) polished copper (b)
DLC....................................................................................................78
Fig. 6-18Steady and transient boiling curve (a) MCNT (b) graphene……79
Fig. 6-19Steady and transient h-ΔT distribution (a) polished copper (b) DLC………………………………………………………………….80
Fig. 6-20Steady and transient h-ΔT distribution (a) MCNT (b) graphene……………………………………………………………..81
Fig. 6-21 havg/hs,avg-hCHF/hs,CHF for different nanotextured surfaces……....82
Fig.6-22 Contact angle (a) polished copper (b) DLC 700 nm (c) DLC 1000 nm (d) MCNT 50 nm (e) MCNT 100 nm (f) MCNT 150 nm (g) graphene 1 nm (h) graphene 2 nm (i) graphene 5 nm (j) graphene 10 nm……………………………………………………………………83

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